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Issue 1, Volume 8,
January 2009
Title
of the Paper: Effect of Strong Linear Polarization Anisotropy on
Geometrical Modes Characteristics of Optical Fiber
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Authors:
Mohammed Yousef Al-Gawagzeh, Mohammed Rasoul Al-Hadidi
Abstract: The geometric polarization in single mode optical fibers is
investigated theoretically and experimentally and the measurement results are
reported. This paper consider the geometrical measurement method of weights
the own modes of poorly directing optical fiber with strong linear anisotropy.
This given method is based on definition the geometrical parameters lines with
equal intensity in a vicinity of zero radiation image from fiber output. The
modes weights have been received as a result of computer processing of
experimental images of intensity distribution at displacement of laser spot
concerning the center of fiber input. It is found that neglecting the
geometrical birefringence, even under the weakly guiding approximation, can
lead to significant errors in the calculation of PMD and the zero PMD
wavelengths. It is also found that one can obtain zero PMD in the single-mode
region even by applying a suitable differential stress along the major axis.
This is very attractive since then the geometrical and stress birefringence
adds up to give increased total birefringence.
Keywords: Anisotropy, double-refraction, polarization, mode weigh, displacement,
intensity distribution
Title
of the Paper: Polarized Modes Dispersion in Anisotropic Optical Fiber
Communication Lines
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Authors:
Mohammed Yousef Al-Gawagzeh, Mohammed Rasoul Al-Hadidi, Rami Al-Rzooq
Abstract: Equations are derived for calculation of the propagation constants
and of the dispersion of the fundamental modes in anisotropic waveguides .This
work shows how to obtain approximate analytic expressions which can be used to
calculate with sufficient accuracy for practical applications the waveguide
and polarization dispersion of the dominant orthogonally polarized modes in
anisotropic optical fiber waveguides and distributions of electric and
magnetic fields of these modes are obtained in a transverse cross section of
the waveguide. It is shown that the anisotropy of a dielectric in the
transverse cross section and the elliptical of the shape of this cross section
alter the waveguide dispersion of modes in such waveguides compared with an
isotropic waveguide. In the case of waveguides which conserve the state of
polarization of the transmitted signal the changes in the waveguide dispersion
due to the transverse anisotropy of the refractive index are considerably
greater than the changes due to the elliptical of the shape of the transverse
cross section of the waveguide. In a waveguide with a transverse anisotropy of
the refractive index the maximum waveguide dispersion of two mutually
orthogonal modes occurs at different frequencies.
Keywords: Dispession, Anisotropy, isotropic dielectric, polarization, Transverse
cross section, Perturbation
Title
of the Paper: Dialectial System Approach and Education Supporting
Environmental Protection
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Authors:
Davorin Kralj
Abstract: Most of the environmental challenges we face could be resolved if
each individual and organization slightly changed their habits and practices.
The key to achieving this is education. The global economic system needs to
show a more human and environment friendly face. Companies must ensure that
their traditional focus on corporate profits and shareholder value is
accompanied by equal concern for the needs of society and the environment. The
article focuses on system approach and education as an influence on
environmental care and protection. Integrated system approach and education
management integrate the requirements of sustainable development and
environmental care. Environmental protection and sustainable development are
result of education and dialectical system approach.
Keywords: Environmental care, environmental education, system approach,
sustainable development
Title
of the Paper: The Performances of the SSC Combiner Output Signal in the
Presence of Log-Normal Fading
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Authors:
Dragana Krstic, Petar Nikolic, Marija Matovic, Ana Matovic, Mihajlo
Stefanovic
Abstract: Level crossing rate, outage probability and average time of fade
duration of the SSC combiner output signal are determined in this paper.
Log-normal fading at the input is present. The results are shown graphically
for different variance values, decision threshold values and fading parameters
values.
Keywords: Diversity reception, Fade Duration, Level Crossing Rate, Log-normal
fading, Outage Probability, SSC Combining
Title
of the Paper: Matching of Interfirm Network and Organizational Learning:
Implications for Technological Innovation
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Authors:
Xinmin Peng
Abstract: There has been a burgeoning literature about interfirm network and
innovative performance. However, in reviewing the extant literature we find
different interpretations regarding how firms should be tied to one another in
networks. The paper employs case study to explore and explain the relative
propositions of interfirm network, different organizational learning and
technological innovation. It addresses two critical research questions. First,
strong ties or cohesive network are valuable in environments that require
exploitation, while weak ties or sparse network would be more appropriate for
exploration. Second, the benefits of each type of interfirm network vary
across each other such that certain types of interfirm network will matter
more or less under different conditions and objectives. Therefore, exploration
and exploitation are two essential organizational learning models, under which
firms need make a reasonable choice between them according the development
stage, environment requirements and innovative targets.
Keywords: Interfirm network, Organizational learning, Exploration, Exploitation,
Network Density, Tie strength, Technological innovation
Title
of the Paper: Study on Significant Technology of H.264 in Mobile Network
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Authors:
Yun-Peng Liu, San-Yuan Zhang, Shu-Chang Xu, Yin Zhang
Abstract: The characteristics of the mobile wireless network are limited
bandwidth and high error rate, at same time the computing and storage capacity
of the mobile devices are limited too. In order to ensure effective video
compression and transmission, H.264/AVC standard provides the significant
technologies and strategies in error resilience strategies?rate control?mode
decision and scalable extension. On the basis of the detailed study in the
strategies, a combination method is proposed, and experiment proves the
quality of video transmission is improved at the same time the rate is
reduced.
Keywords: Video transmission, H.264, Mobile network, Wireless transmission, Rate
control, Error resilience, Mode decision, Scalable extension
Title
of the Paper: An Algorithm Reliability of Wireless Networks for Sum of
Disjoint Poroduct and Topological Structure
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Authors:
Fei Gao, Chen Zhao, HaoLiang Hu, JiangGang Yang
Abstract: A new formula for computing ST reliability of wireless networks from
Source to Terminal t was presented. The formula is a combination of IE and
SDP, and the Satyaranayanna’s formula is its special case. The new formula
contains terms which correspond one by one to a class Special subnetworks ,
For a given networks, the terms of the new formula are fewer than those
corresponding Satyaranayanna’s formula. An algorithm for computing ST
reliability was presented, it computed ST reliability or produced a ST
reliability expression by enumerating a class of Special networks of given
networks. Because the structure of this class of new networks which need to be
enumerated was relativity small, the new algorithm’s performance was better
than Satyaranayanna’s algorithm .Finally an example illustrates our
conclusion.
Keywords: Reliability, Reliability expression, inclusion exclusion principle,
wireless network
Title
of the Paper: Research of Utility Prepayment System based on Wireless
Communication
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Authors:
Pan Tie-Jun, Zheng Lei-Na, Zhang Hua-Jun, Fang Chen-Bin
Abstract: This paper seeks to clarify differences and similarities among
impressive array of radio access technologies which can be used in utility
prepayment, analyzes the requirements of wireless prepayment utility meter
system. It present a set of mobile prepayment solution in which the prepayment
meter (PM) system is implemented without smart card and user need not go to
agency by oneself for prepayment. For the purpose of solving the difficult
problem of utility meter prepayment at the specific location in person, mobile
payment client (MPC) with graph user interface (GUI) located on mobile device
which is responded for business initiation. PM is connected to PS via Zigbee
network or WLAN in short range access network and via the 3rd generation
wireless communication infrastructure (3G) in long range access network, and
utility meter may connect Zigbee node via RS485 bus. By means of
identification and mutual authentication which generating different session
key with time stamps every time, the cross validation mechanism among PM, MPC
and PS improve the security of mobile prepayment system. The security
mechanism is given in the end including user identification, mutual
authentication, and data integrity and data confidentiality. In the end,
ZigBee node hardware design and meter interface design is introduced and a
practical application is given. The result of the present work implied that
mobile phone is gradually becoming a data access and exchange platform of
mobile payment, and WiMax is another competitive technology which will be used
in the utility wireless prepayment solution.
Keywords: Mobile payment, OTA, Zigbee, WiMax, 3G, meter, RS485
Title
of the Paper: Combining Web Services Toward Innovative Design of Agile
Virtual Enterprise Supported by Web 3.0
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Authors:
Pan Tie-Jun, Zheng Lei-Na, Zhang Hua-Jun, Fang Chen-Bin, Lou Jie, Shao
Zhong
Abstract: With the Internet dominating the business world, the need to have an
effective web3.0 service has increased among Agile Virtual
Enterprise(AVE)emerging out of the context of globalization manufacturing,
Innovative design is seen as the core competitiveness of AVE which need the
knowledge engineering method urgently. However, the current human readable web
can not meet the demands of complexity, flexibility and Real-time for
innovation design. Until the emergence of the web 3.0, it is possible for
intelligent software agent based on machine accessible SOA services which can
be combined to higher level of enterprise web services. We give a new
innovative design platform by combining enterprising Web Services based on Web
3.0. This paper gives ontology for innovative design which including design,
process, skill, application domain and organization sub ontology and the OWL
description of environmental production domain. Then we complete the
innovative design service model by Protege tools, setup the design service web
platform based on J2EE with Protege-OWL API, and give a practical case in the
domain of environmental protection device manufacturing. In the end, we points
the performance of knowledge database is important in the future.
Keywords: Knowledge, innovative design, Agile Virtual Enterprise, semantic,
ontology, web services
Title
of the Paper: Research on the Application of Education Information Service
Platform Based on WebGIS
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Authors:
Zheng Yue-Feng, Ma Wei-Feng, Mao Ke-Ji
Abstract: Along with the development of education, it becomes more and more
important to issue and gain the education information day by day. According to
the education information’s characteristic, we can change the single attribute
query type to a better one which can satisfies the requirement of education
information service through the Web Geographic Information System(WebGIS).This
paper proposes a new design for education information service platform based
on WebGIS, and analyses the key technologies including MapXtreme’s basic work
principle, the architecture and so on. At the same time, the paper introduces
the function of service platform, data structure and the implementation method
of MapXtreme in detail by ASP.
Keywords: Education information service platform, WebGIS, MapXtreme
Title
of the Paper: On the Importance of Securing Telephony Systems
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Authors:
Iosif I. Androulidakis
Abstract: In the following work we present an easy to read essay about the
array of threats that modern telephony systems face, that will prove,
hopefully, useful for both administrators and simple users. We have
taxonomized these threats and we have further provided some useful tips for
safeguarding these systems in order to keep enjoying one of the most valuable
goods: That of communication.
Keywords: Telephony Threats, Telephony Fraud, Communication Systems Security
Title
of the Paper: Generating a Set of Rules to Determine the Gender of a
Speaker of a Japanese Sentence
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Authors:
Kanako Komiya, Chikara Igarashi, Kazutomo Shibahara, Koji Fujimoto,
Yasuhiro Tajima, Yoshiyuki Kotani
Abstract: Some work has been reported on the problem of automatically
determining the gender of a document’s author as a part of researches to
extract features of a document’s author. Japanese language has expressions
called masculine/feminine expression, and they can often indicate the gender
of a speaker of a conversational sentence. The computer system needs this
mechanism in order to make or understand natural Japanese conversational
sentences.
The authors made a system that determines the suitable gender of a speaker of
a single conversational sentence and named it gender-determining system (GDS).
It generates a set of rules to determine the more suitable gender of a speaker
of a sentence automatically, by decision tree learning. The authors employed
six linguistic features for each of two morphemes at the end of a sentence and
presence or absence of morphemes whose part of speech is a miscellaneous
pronoun or a particle for ending as features of decision tree learning. The
authors calculated the accuracy of GDS using the cross validation method and
it was approximately 69.3% when human could answer the same problem with
approximately 71.7%. The authors showed decision tree learning is more
suitable than multiple regression analysis or Bayesian estimation in order to
classify the gender of the speaker of Japanese sentences and generate a set of
rules to determine them, and selected the suitable features as the inputs of
GDS. The set of rules GDS generated indicates, for example, women speak more
politely than men in Japan.
Keywords: Natural language processing, rule generation, decision tree learning,
gender-determining, knowledge acquisition, data mining
Title
of the Paper: A Cross-Layer Based Joint Algorithm for Power Control and
Scheduling in CDMA Wireless Ad-Hoc Networks
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Authors:
Rekha Patil, A. Damodaram
Abstract: In CDMA wireless ad-hoc networks; an important goal is, permitting
the requested calls of different users maintaining the quality of service.
Because of interference and power, the CDMA capacity is restricted in general.
The interference will increase as soon as the number of users rises by the
reason of non-orthogonal factor. Consequently, there is a limit to the maximum
number of users. In this paper, a cross-layer based joint scheduling and power
control algorithm has been proposed with the objective of minimizing the
interference level and call rejection rate. For achieving this, the algorithm
determines the optimum set of admissible users with suitable transmitting
power level. We introduce the notion of power control as part of a
contention-based multiple access protocol that characterizes successful
transmissions depending on a set of signal-to-interference-and-noise ratio (SINR)
constraints (which directly translates to quality of service (QoS) constraints
on the bit-error rate (BER) at individual receivers). The performance of our
algorithm in a set of admissible and non-admissible users has been assessed
using simulation results. Moreover, it is exposed that power control algorithm
converges for a set of admissible users.
Keywords: Ad-hoc networks, CDMA, SINR (signal-to-interference-and-noise ratio),
QoS (Quality of service), BER (bit-error rate), Cross layer design
Title
of the Paper: The Communication Unit of Measuring Device in Power
Engineering
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Authors:
Petr Mlynek, Martin Koutny, Jiri Misurec
Abstract: Various devices, for example electrometers, can be connected to the
Internet by means of the communication unit. Thanks to the communication unit,
remote acquisition of power consumption data is enabled. This article focuses
on the design of the communication unit for remote data acquisition. The
article also deals with the design and implementation of the authentication,
secure data transmission, and transmission block integrity. Finally describes
the system for testing robustness of the communication unit.
Keywords: Communication unit, remote data acquisition, RCM3700, Internet,
measuring device, authentication, transmission block, Dynamic C, attack
Title
of the Paper: Flexible Authentication Framework with Bound Authentication
and Authorization
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Authors:
Jan Hajny, Tomas Pelka, Vaclav Zeman
Abstract: User authentication is an important part of computer network
cryptography. It becomes more and more essential for security with the latest
progress in the field of computer science. We analyze latest trends in the
article. Our goal is to answer the question whether these trends reflect
current state in computer networks. We are focused on security and from this
point of view we find the progress unsatisfactory. The reason is that most of
current work is focused on operational parameters more than on security.
That’s why we give an example of less known authentication methods which can
solve the most important issues of current protocols – security and protocol
flexibility. The main advantage of one of these methods is its mathematical
model which can prove security. As the flexibility of the method is also vital
for modern multi domain networks we provide a modification of this method to
improve the process of authentication and authorization.
Keywords: Cryptography, Authentication, Authorization, Security, Zero-Knowledge,
Password-based authentication
Title
of the Paper: On the Design of an Ohmic RF MEMS Switch for Reconfigurable
Microstrip Antenna Applications
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Authors:
M. Spasos, N. Charalampidis, N. Mallios, D. Kampitaki, K. Tsiakmakis, P.
Tsivos Soel, R. Nilavalan
Abstract: This paper presents the analysis, design and simulation of a direct
contact (dc) RF MEMS switch specified for reconfigurable microstrip array
antennas. The proposed switch is indented to be built on PCB via a monolithic
technology together with the antenna patches. The proposed switch will be used
to allow antenna beamforming in the operating frequency range between 2GHz and
4GHz. This application requires a great number of these switches to be
integrated with an array of microstrip patch elements. The proposed switch
fulfills the switching characteristics as concerns the five requirements
(loss, linearity, voltage/power handling, small size/power consumption,
temperature), following a relatively simple design, which ensures reliability,
robustness and high fabrication yield.
Keywords: Ohmic, resistive, direct contact, switch, RF MEMS, PCB,
reconfigurable, microstrip antenna array
Title
of the Paper: Methodological Issues in Cross-Cultural and Interdisciplinary
Research on Sustainable Development
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Authors:
Anita Trnavcevic, Davorin Kralj
Abstract: One of the perspectives is to understand and place sustainable
development within broader picture of globalization and paradigm shift. As
long as we ‘neatly’ divide education, sustainable development and politics we
can discuss them as separate ‘fields’ of work. Globalization is associated
with processes, such as internationalization, international relationships,
unification and diversity, local and global and similar. It ‘occurs’ in all
areas of social life and from some points of view in all scientific
disciplines.
The purpose of this article is to present methodological issues related to
interdisciplinary and cross-cultural research and sustainable development. We
can observe cross-cultural research in management, education, and in other
disciplines of social sciences. Cross-cultural research, however, requires
translation. If research is understood as a form of communication then
cultural dimension play role in data collection stage as well as in other
stages of research design. When questionnaires, tests and other instruments of
data collection are used in different cultural and linguistic groups a
question of equivalence becomes essential. Our consideration is that
questionnaires like ours are subjected to double translations: from one field
or discipline to other and from one language to other. In these double
translations cultural equivalence basically cannot be ensured. Qualitative
studies, however, can embrace cultural dimension.
Keywords: Cultural equivalence, cross-cultural research, education,
interdisciplinary research
Title
of the Paper: An Efficient Partition and Matching Algorithm for
Query-Set-based Broadcasting in Multiple Channel Mobile Environment
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Authors:
Jing-Feng Lin, Guang-Ming Wu, Derchian Tsaih
Abstract: Broadcast is an efficient and scalable method for resolving the
bandwidth limitation in a wireless environment. In many applications, mobile
clients might need more than one data item. However, most previous researches
on query-set-based broadcasting are restricted to a single broadcast channel
environment. The results are limited applicability to the upcoming mobile
environments. In this paper, we relax this restriction and explore the problem
of query-set-based broadcasting in multiple broadcast channels. In
multi-channel query-set-based broadcasting, we discover data collision (two
data items in the same query set are arranged on two channels at the same time
slot) is an important factor to affect users’ access time. In this paper, we
introduce the new data collision problem motivated by multi-channel
query-set-based broadcasting environment. We then present a two-stage scheme
of data partitioning and data matching to solve the new data collision
problem. Experiments are performed to justify the benefit of our approach.
Keywords: Access time, data broadcast, mobile environment, multi-channel,
query-set-based broadcasting
Title
of the Paper: An Investigation on User Communication Behavior in an
Interactive Whiteboard Technology Environment
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Authors:
Chia-Cheng Shen, Huan-Ming Chuang
Abstract: Interactivity is the key characteristic in interactive whiteboard
technology (IWT). This study aims to provide a better understanding of
communication behavior in IWT. This research’s objective is to investigate the
effects of the interactivity level on a user’s attitude and intention toward
the use of IWT. As a result, we cite the technology acceptance model (TAM) to
support this research. Specifically speaking, our test consisted of system
characteristics (interactivity) and extrinsic motivation (TAM), in an
integrated theoretical framework of IWT behavior. A survey of 340 elementary
school students found strong support for the model. We used the confirmatory
factor analysis (CFA) to examine the measurement model, and applied structure
equation modeling to access the empirical strength of the relationships in the
proposed framework. Overall, the conclusions were placed into two categories:
methodological and theoretical. On the methodological front, we demonstrate
the development of a reliable and valid measure that captures a critical
construct to understand IWT behaviors. On the theoretical front, the results
reveal that attitude and behavioral intention are directly/indirectly affected
by interactivity, perceived ease of use, and perceived usefulness.
Keywords: Interactive whiteboard technology (IWT), Interactivity, Technology
Acceptance Model (TAM)
Title
of the Paper: Adaptive MMSE Rake-Equalizer Receiver Design with Channel
Estimation for DS-UWB System
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Authors:
Yi-Jen Chiu
Abstract: In this paper, a robust adaptive MMSE Rake-equalizer receiver scheme
is presented with channel estimation that has been transmitted in Direct
Sequence-Ultra Wideband (DS-UWB) system. The DS-UWB has a fine path resolution
by transmitting information with ultra short pulses. The Rake receiver is
known as a technique that can effectively combine paths with different delays
and obtain the path diversity gain. Due to sub-nano seconds narrow pulse and
the large transmission bandwidth in the systems, we therefore use equalizer to
overcome the resulting ISI and a long delay spread in the characterization of
the UWB channel. The proposed receiver structure reduces intense multi-path
destruction and severe inter-symbol interference (ISI) by using a combined
adaptive Rake and equalizer structure referred to as the MMSE (minimum mean
square error) algorithm. Channel information is obtained through the use of a
least mean square (LMS) adaptive algorithm on the training sequence of a
preamble. The indoor environment is represented by dense multipath channel
models proposed by IEEE 802.15.3a. Simulation results show that the new scheme
employing the energy of a few paths to obtain better performance than the
traditional maximum ratio combining (MRC) Rake receiver.
Keywords: Least mean squares (LMS), minimum mean square error (MMSE), adaptive
receiver, direct sequence ultra wideband (DS-UWB)
Issue 2, Volume 8,
February 2009
Title
of the Paper: A Wide-Beam Array Antenna Using Shorted-End Curved Dipoles on
a Reflector Plane
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Authors:
Rangsan Wongsan
Abstract: This paper presents a wide-beam array antenna for broadcasting
station by using two curved dipoles, which its both ends of each dipole are
electrically shorted on the surface of a square conducting reflector and
connected to the ground system and the feed point is excited at the center of
each one. Advantage of this antenna should possess physically strong
structure, easy fabrication, and cost effectiveness. Because of the elements
of array are made of the straight dipoles, which their arms are curved for
enlarging the beamwidth and shorted on a metallic reflector for increasing
total directive gain and robusting the structure. The Method of Moment (MoM)
is utilized to solve numerically the electrical currents that distribute along
the curved dipole, which are used to determine the impedance characteristics
and the radiation patterns of this antenna. The beamwidth of azimuth pattern
of the proposed antenna is around 12, which is suitable for achieving
omnidirectional pattern for TV broadcasting station by placing them around the
tower at least three panels. Having confirmed the validity of this approach,
the UHF-band antenna prototype is fabricated, tested experimentally and shows
good performance.
Keywords: Curved dipole, array antenna, wide-beam antenna, broadcasting antenna,
method of moment
Title
of the Paper: Constructing a New Communication System by Integrating the
GSM to the Satellites Infrastructure
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Authors:
Muzhir Sh. Al-Ani, Basil M. Al-Kasasbeh, Rafa E. Al-Qutaish, Mohammad I.
Muhairat
Abstract: The current researches and industries are looking forward to
integrate different technologies to get a global technology that offers all of
the intended services in a simple way. In this paper, a new communications
system is proposed to integrate the use of GSM over the available satellites
infrastructures. The proposed communications system could be used to
facilitates and get benefits of both systems (the GSM and Satellites) to
achieve competitive services over the world. The proposed system is
concentrated on a global communications system that served all over the world
and gives some specialization and privacy for each country. Furthermore, this
paper shows an algorithm on how to implement the GSM over satellite systems in
an efficient, flexible, and cost-effective manner.
Keywords: GSM, GSM over Satellite, Mobile Communications, Satellite
Communications
Title
of the Paper: Enhancing DSR Protocol Performance in Mobile Ad Hoc Network
Using ACK Reply
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Authors:
Abdullah Gani, Qi Han, Nor Badrul Anuar, Omar Zakaria
Abstract: This paper presents a new method to improve performance of DSR in Ad
Hoc Network. We present an analysis of DSR protocol and propose our algorithm
to improve the performance of DSR protocol by using ACK reply path as a backup
route when an original route fails in Mobile Ad Hoc networks. In the
traditional DSR protocol, a backup route will be initiated to transfer data in
route cache when a route is broken. However, if the backup route is also
failed, it will affect the overall network performance. We modify the DSR
so-called Modified DSR protocol (MDSR) with the aim that the source node can
still receive the ACK reply from destination node when an original route is
broken, which means data packets can be transferred along with the ACK path.
MDSR deploys the idea of TCP-BuS to solve unnecessary resending of lost data
packets. We simulate our proposed model in NS2, compare the MDSR with DSR in
the performance of end-to-end delay and packet delivery ratio. The result
shows that the performance of MDSR is better than the traditional DSR
protocol.
Keywords: Ad Hoc, Wireless Network, DSR protocol, ACK, Performance
Title
of the Paper: Functioning the Intelligent Programming to find Minimum
Dispersion Wavelengths
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Authors:
Maan M. Shaker, Mahmood Sh. Majeed, Raid W. Daoud
Abstract: A new method based on genetic concepts is suggested to analyze and
determine the transmission (propagation and dispersion) characteristics for
conventional fibers as well as photonic crystal fibers. The power and the
advantage of this work, lie in the fact that it could be applied to any
optical fibers type with any refractive index profile and the method computes
its proper and accurate propagation constant which leads to investigate the
desired dispersion and minimizes it to the least possible value.
Keywords: Optical fibers, PCF, dispersion and genetic algorithm
Title
of the Paper: Theoretical Optimum Designation of Distributed Raman
Amplifiers in Different Media
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Authors:
Farzin Emami, Amir H. Jafari
Abstract: Raman Amplifiers (RAs) are a group of amplifiers which have various
applications in optical communications. Data transmission media utilized for
RAs are optical fibers operating in nonlinear regime. We present the
performances and characteristics of RAs by utilizing a set of coupled
differential equations and numerical simulations. Two types of fibers with
different gain characteristics, germanium-doped and silica fibers are used in
our numerical simulations. So, the optimum initial values of the pump powers
for a system with 10 pumps are recalculated and optimized again. We did our
simulation to have a flat gain and low noise characteristics. Another aspect
of the fiber media is their effective areas and we studied the effects of this
parameter on the net gain of the RAs. Finally, the noise figure computations
are discussed for our 10 pumps bidirectional amplifier which is optimized.
Keywords: Raman amplifiers, Noise figure, Nonlinear gain, Numerical simulation,
Optimization
Title
of the Paper: Behavioral Modeling and Simulation of Underwater Channel
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Authors:
Nejah Nasri, Laurent Andrieux, Abdennaceur Kachouri, Mounir Samet
Abstract: The Ocean is a dynamic and complex environment; it is a very
complicated transmission channel that can change rapidly with the
environmental conditions. Hence, to avoid failure of underwater monitoring
missions, it’s crucial to predict the behavior of underwater acoustic channel.
In this paper, several fundamental key aspects of underwater acoustic channel
are investigated. A model characterizing the underwater acoustic channel is
introduced, and how underwater channel can be simulated is discussed. In
addition, this paper describes a methodology for top-down design, modeling,
and simulation of underwater channel using hardware description language
VHDL-AMS. The following analysis may provide precious guidelines for the
design of underwater communication systems.
Keywords: Underwater communication, underwater channel model, behavior modeling
acoustic signal, VHDL-AMS language
Title
of the Paper: A Distributed Adaptive Scheme for Detecting Faults inWireless
Sensor Networks
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Authors:
Jae-Young Choi, Sung-Jib Yim, Yoon Jae Huh, Yoon-Hwa Choi
Abstract: This paper presents a distributed adaptive scheme for detecting
faults in wireless sensor networks. Each sensor nodes makes a local decision
based on the comparisons of its own readings with those of neighbors, along
with the dissemination of the decision to them, if necessary. At the end of
each fault detection cycle, each node dynamically adjusts critical parameters
in the distributed fault detection algorithm, such as node degree and
thresholds, resulting in high performance for a wide range of fault
probabilities. By extensive computer simulation the scheme is shown to be
scalable with the number of faulty sensor nodes except for sparse networks
where the average node degree is extremely low.
Keywords: Sensor networks, distributed, adaptive, fault detection, fault
diagnosis
Title
of the Paper: Wide-Band Beamformer with Integrated Antennas
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Authors:
Amirhossein Fereidountabar
Abstract: As part of the development of a new international radio-telescope
SKA (Square Kilometer Array), three phased-array prototypes with increasing
complexity have been developed. The final SKA telescope will consist of more
than one million receiving antenna elements and will operate in the frequency
range of 200 to 2000 MHz. One of the challenges of the next generation radio
telescopes for astronomy is its capacity to cope with the increasing problem
of Radio Frequency Interference (RFI). The application of phased-array
beamforming techniques opens the possibility to spatially null RFI in the
digital domain prior to correlation. This paper presents results from the
third phased-array experimental demonstrator that is being developed at NFRA,
the THousand Element Array (THEA), on the RF Beamformer boards with integrated
antenna array.
Keywords: Beamforming, Antenna arrays, Wideband beamformer, Sensitivity,
Integrated antennas, Dual beam, Measurement, Testing
Title
of the Paper: Energy Level and Link State Aware AODV Route Request
Forwarding Mechanism Research
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Authors:
Hao Jutao, Zhao Jingjing, Li Minglu
Abstract: Ad-hoc On-demand Distance Vector (AODV) provides scalable and
effective solution for packet routing in mobile wireless ad hoc networks,
however, the path generated by this protocol may derivate far from optimal
because of inconsideration of node power ,load unbalance and link
state,resulting in energy consumption of each nods is imbalanced and reduce
the lifetime of whole networks. Based on the basic AODV protocols, an improved
protocol is presented in this paper. When the protocol is selecting a route,
node power, load status and link state between nodes are all considered. The
proposed protocol can improve the network performance. Through the simulation
on NS2, it is confirmed that the improved AODV protocol has higher package
delivery ratio, lower end to end delay and lower routing overhead than basic
AODV protocol.
Keywords: On demand distance vector routing,Mobile Ad hoc networks , Link state,
Energy aware routing
Title
of the Paper: The Implementation of Satellite Images and Associated Digital
Image Processing in Addition to GIS Modelling for Urban Mapping in Amman area,
Jordan
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Authors:
Eyad H. R. Fadda, Maher Kakish, Tariq A. Al Azab
Abstract: Thematic maps and geo-spatial database are important tools that can
be used for many purposes, such as mapping urban features, agricultural area
and road network; they are also useful in urban planning and city planning.
Many urban features were depicted from topographic maps and satellite digital
images covering west of Amman area. GIS, remote sensing and associated digital
image processing techniques have been applied on the satellite digital images
in order to enhance the images. On screen digitizing techniques for both
topographic and satellite images were applied to delineate Urban areas,
agricultural areas, road networks. Several new maps for the western part of
Amman area were produced from the topographic maps and satellite images (IKONOS
2002 and 2006). The resultant maps are: urban areas, road networks and
agricultural area. The produced layers and their attributes were stored as
geo-spatial database for west of Amman area using GIS technology by Arc GIS
software. The produced maps and layers can be used for urban planning.
Keywords: Digital image processing techniques, Digital mapping, GIS modelling,
Spatial domain filters, Geospatial database and Urban mapping
Issue 3, Volume 8,
March 2009
Title
of the Paper: Parallel Tabu Search for Optimizing the OSPF Weight Setting
Problem
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Authors:
Sadiq M. Sait, Mohammed H. Sqalli, Syed Asadullah
Abstract: The problem of setting the Open Shortest Path First (OSPF) weights
on links such that congestion can be avoided is proved to be NP-hard. Many
iterative heuristics have been applied to solve the OSPF weight setting (OSPFWS)
problem. As the size of any combinatorial optimization problem increases, it
becomes more difficult to find an optimum solution using sequential
algorithms. Parallelization of modern iterative heuristics has been proven to
produce improved solution precision and timing. In this paper, we investigate
the parallelization of Tabu Search and apply two variants of a Parallel Tabu
Search (PTS) heuristic on the OSPFWS problem. It is shown through experimental
results that both PTS approaches produced better solutions quality compared to
the sequential heuristics; specifically for larger topologies. In one
approach, we propose a new design for our parallel cooperative search
algorithm, which performs better than the conventional parallel heuristic. The
purpose of this new design is to induce diversification into the search to
explore a larger search space. We also show that the new approach performs
better than the conventional parallel heuristic.
Keywords: Open Shortest Path First (OSPF), OSPF Weight Setting Problem, NP-hard,
Iterative Heuristics, Parallel Tabu Search
Title
of the Paper: Processing Data for Colored Noise Using a Dynamic State
Estimator
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Authors:
Marius-Constantin Popescu, Onisifor Olaru, Nikos Mastorakis
Abstract: This paper treats data reduction in array processing for the
spatially colored noise case. The purpose is to reduce the computational
complexity of the applied signal processing algorithms by mapping the data
into a space of lower dimension by means of a linear transformation. We
discuss ways to implement the transformation and show that it suffices to
estimate the array covariance matrix instead of the noise covariance matrix in
the design process of the optimal transformation. Computer simulations are
given that illustrate the problem of interference from out-of-band-sources
that result when a beamspace transformation is designed to focus on a
particular sector. The presents an dynamic state estimator. The method uses
ANN based bus load prediction for the prediction step in the DSE.
Keywords: Adaptive data reduction, Colored noise, Dynamic state estimation, Load
prediction
Title
of the Paper: Sustainable Business and Environmental Indicators
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Authors:
Uros Ogrin, Davorin Kralj
Abstract: This article focuses primarily on the research in Sustainable
Business and Environmental Indicators of 120 Slovenian companies, in view of a
general environmental management model. The research for this paper is based
on the collection and analysis of quantitative and qualitative data. From
research results, we can conclude that at a declarative level, environmental
care is reflected in leadership and policy, strategy and organizational
culture in the area of environmental management, where as the actual care is
implemented in the processes related to this area. System thinking and multi
view approaches, which are a must for a successful establishment of a
sustainable business and environmental indicators, are of great importance. It
is essential for the real effectiveness of environmental management to have
appropriate leadership and keep well-regulated interpersonal relations in an
enterprise. Congenial and stimulating atmosphere, promoting relaxed free and
unimpeded activities, work satisfaction and satisfaction with co-operation
with others, are all elements distinguishing excellent performance. When
implementing changes, employees should be motivated adequately. Environmental
indicators are powerful tools that serve many purposes, useful as tools for
performance evaluation and public information. The development of indicators
is a dynamic process that is constantly subject to updating and improvement.
Keywords: Environment, environmental indicator, management, sustainable
business, sustainable development
Title
of the Paper: An OFDM-based Transmission Scheme for Underwater Acoustic
Multimedia
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Authors:
Chin-Feng Lin, Chen-Hsiang Shih, Cheng-Pin Chen, Shao-Wei Leu, Jiing-Kae
Wu, Ching-Hsiang Tseng, Hsien-Sen Hung, Fu-Sheng Lu, Ivan A. Parinov, Shun-Hsyung
Chang
Abstract: In this paper, we propose an orthogonal frequency division
multiplexing–based (OFDM-based) underwater acoustic multimedia system. An
essential feature of this system is that it offers greater power and schemes
with significant error protection for the transmission of sensor data
information requiring a higher quality of service (QoS). To realize maximum
resource utilization or minimum total transmission power, we also include an
adaptive modulation strategy into the system. The proposed underwater acoustic
multimedia system employs high power, low speed modulation, and schemes
providing significant error protection for the transmission of sensor data
messages requiring a stringent bit-error rate (BER). In contrast, low power,
high speed modulation, and less capable error protection schemes are provided
for messages that can tolerate a high BER. A simulation was carried out to
verify the functionality of the proposed system in a practical underwater
acoustic multimedia scenario.
Keywords: Underwater multimedia, acoustic, OFDM, QoS, power assignment, unequal
error protection, adaptive modulation
Title
of the Paper: Analysis of a Fixed-Complexity Sphere Decoding Method for
Spatial Multiplexing MIMO
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Authors:
M. Haridim, H. Matzner, V. Neder, D. Ezri
Abstract: A new detection algorithm for decoding multiple-input
multiple-output (MIMO) transmission is proposed and analyzed. The method is
based on combining sphere decoding (SD) and zero forcing (ZF) techniques. The
proposed method performs a fixed number of operations to detect the signal,
independent of the noise level, and hence provides a fixed complexity near
optimal performance. The algorithm is especially suited for systems with a
large number of transmit antennas and allows efficient implementation in
hardware. The high efficiency of this algorithm is obtained by limiting the
number of overall SD iterations. Moreover, in the proposed method matrices
with high condition number are more likely to undergo SD.
Keywords: MIMO, detection complexity, spatial multiplexing, sphere decoding,
zero forcing, maximumlikelihood
Title
of the Paper: Communication and Processing Consideration for Alerting
Systems Implemented through Mobile Sensor Networks
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Authors:
Dan Popescu, Radu Dobrescu, Maximilian Nicolae, Alexandru Iordan
Abstract: At the beginning of the paper it is presented an alerting system
architecture based on mobile sensor network. Then it is analyzed the current
available radio communication infrastructure which can be used for
implementation of alerting systems in conjunction with the alerting systems
requirements. Further we shown how the digital signal processor (DSPs) are the
best fit for the processing level. We propose some ideas of selection
criterion based on this analyze and an implementation of a mobile sensor
network with applicability in alerting systems. Built with the purpose of
surveillance, data gathering and warning, alert systems could benefit from the
increase flexibility offered by a mobile sensor network. In order to ensure a
low cost and an extended battery life, for communication between nodes the
ZigBee standard was chosen. For the prompt response of the system we design a
software kernel with real time operation and implement on DSP architecture.
Keywords: Mobile sensor networks, Alert system, Communication protocols, Digital
signal processing, Power consumption, Software structure
Issue 4, Volume 8,
April 2009
Title
of the Paper: Practical Horizon Plane and Communication Duration for Low
Earth Orbiting (LEO) Satellite Ground Stations
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Authors:
Shkelzen Cakaj
Abstract: Communication via satellite begins when the satellite is positioned
in the desired orbital position. Ground stations can communicate with LEO (Low
Earth Orbiting) satellites only when the satellite is in their visibility
region. The visibility region is in fact the horizon plane. Because of natural
barriers or too high buildings in urban areas, practical horizon plane differs
from the ideal one. The duration of the visibility and so the communication
duration varies for each satellite pass at the ground station, specifically
for LEO satellites which do move too fast over the Earth. This paper discusses
the satellites motion detection, the difference in between ideal and practical
horizon and further the variations of the communication duration between the
ground station and LEO satellites. Main objective is determination of
practical horizon plane and critical maximal elevation angle related to
communication duration. For this paper, data recorded at the Vienna satellite
ground station within the Canadian space observation project “MOST” (Micro
variability and Oscillations of Stars) are applied. Vienna ground station
system was set up at the Institute for Astronomy of the University of Vienna
in cooperation with the Institute of Communications and Radio- Frequency
Engineering of the University of Technology in Vienna.
Keywords: LEO, satellite, ground station, elevation, azimuth, horizon plane,
communication duration
Title
of the Paper: Computer Network Routing Based on Imprecise Routing Tables
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Authors:
Milan Tuba
Abstract: This paper examines problems that arise from the fact that dynamic
routing never relies on the precise, current information about the network
state. It is a normal expectation that dynamic routing has to give better
results than a static one. However, it takes some time to collect information
about the network current state, and optimization is always done with that
imprecise information. This situation is examined by a complete mathematical
analysis of a simple network. We show that dynamic routing gives better
results than static, as expected, but that the margin is much smaller then
intuitively expected. Further analysis shows that that minor advantage can
easily be lost if there is even a small error in the dynamic routing tables,
and actually dynamic routing can easily become worse than static. Quantitative
analysis shows that delays in building routing tables can affect dynamic
routing performance unexpectedly strongly. The conclusion is that dynamic
routing should not try to adapt to traffic changes very fast.
Keywords: Computer network routing, Static optimization, Dynamic optimization,
Modeling
Title
of the Paper: On-line PBL System Flows and User's Motivation
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Authors:
Hsieh-Hua Yang, Lung-Hsing Kuo, Hung-Jen Yang, Jui-Chen Yu, Li-Min Chen
Abstract: Problem-based learning is the bridge to connect learners with real
world and is the trigger setting for high level thinking skill. On-line
technology is supporting our learning in many ways. There is a need to
understand not only what framework could help conduct on-line problem-based
learning but also the learner’s motivation. The purpose of this study was to
draw up a framework of on-line problem-based learning. Based on literature
review, a theoretical framework was identified. An implementation of this
framework was conducted to verify the feasibility based upon the learner’s
motivation. Motivation survey was conducted to explore the learner’s response.
Concerning the framework of on-line PBL, the results of the evaluation
conducted in this study implied that the feasibility existed. Pertaining to
motivation, learners suggested that their motivations were from both the
on-line social network and real world problem.
Keywords: Problem-based learning, On-line system flow, Motivation
Title
of the Paper: Creating a Virtual Information Center for Industrial Design
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Authors:
Manlai You, Li-Min Chen, Lung-Hsing Kuo, Hung-Jen Yang, Hsieh-Hua Yang, Jui-Chen
Yu
Abstract: The purpose of this study was to propose a layout of an on-line
information center for industrial design. Based upon literature review, the
major component was revealed. The design information center should be a
multimedia database which was designed to support the activities of industrial
product designers globally. In this study, user data services were created.
The multimedia data types, user interface issues, database construction, and
intended audience were discussed. This paper provides a general outline of
designing an on-line information center for industrial design. Its aims and
objectives, the innovative application of technology, and the underlying
network structures were also proposed.
Keywords: On-line information center, industrial design
Title
of the Paper: Assessing and Managing Mobile Technostress
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Authors:
Jui-Chen Yu, Lung-Hsing Kuo, Li-Min Chen, Hung-Jen Yang, Hsieh-Hua Yang,
Wen-Chen Hu
Abstract: From time to time, new technology brings people impacts. Mobile
information system provides new way for manipulating information in both
directions, sending out and bringing in. Anywhere and anytime are both the
characteristics of mobile technology that people could get rid of. The purpose
of this study was to explore mobile technostress and bring up the discussion
of assessing and managing. A balance theory was concluded and how to cope with
mobile technostress was also discussed.
Keywords: Mobile technostress, characteristics of mobile technology, balance
scale
Issue 5, Volume 8,
May 2009
Title
of the Paper: Equalization of Energy Consumption at Cluster Head for
Prolonging Lifetime in Cluster-based Wireless Sensor Networks
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Authors:
Yung-Fa Huang, Neng-Chung Wang, Chin-Ling Chen, Jong-Shin Chen, Zong-Min
Guo
Abstract: In cluster-based wireless sensor networks (WSN), the most of energy
is consumed in cluster head which performs data aggregations and relaying. The
lifetime in cluster-based WSN is subjected by the lifetime of cluster heads.
Therefore, in this paper, we equalize the energy consumption of the cluster
heads to prolong the lifetime of WSN. After equalization, we obtain the length
of sides of cluster area. Numerical results show that the length of far site
cluster is shorter than the nearest cluster to perform equalization for all
three routing schemes. Moreover, simulation results show that the three-hop
scheme can obtain the most energy efficiency than other two schemes.
Keywords: Wireless sensor network, Clustering, energy efficiency, Cluster head,
Energy consumption equalization, Network lifetime
Title
of the Paper: Remote Control Technique with OFDMA Based Approach for
Biologically Inspired Robots in a Mobile Ad hoc Network (MANET)
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Authors:
R. P. Chatterjee, B. Sutradhar, Uma Dutta
Abstract: Wireless communication is adding improvements in remote controlling
techniques of vehicles or mobile robots day by day. From mission based AGVs to
biologically inspired robots each area of robotic research is being enriched
from time to time with the advent of Wi-Fi technologies like 1G, 2G, and 3G
etc. This paper reflects a novel approach to control a mobile ad hoc network
built with a number of snake robots to monitor an area like coal mines. Each
agent of this network is having DSP based controller for processing files and
instructions from remote computer through a wireless network structured in
orthogonal frequency division access approach. DSP controllers redirect the
segments of the robot to exhibit snake-like locomotion. Desired transfer
function for lateral undulation is derived using two controller design
approach such as, graphical domain approach and frequency response approach
and the impulse response of each controller are loaded segment-wise in each
agent. Length and segment-wise distinction for every robot is considered for
wireless file transfer and instruction from remote station within a limited
bandwidth. Problems due to inter-symbol interference (ISI), multipath fading
and limitation of ISM band have also been overcome.
Keywords: Biologically inspired robot, snake robot, OFDMA, MANET
Title
of the Paper: Perceptual Evaluation of Speech Quality for iLBC Vocoder with
Uneven Level Protection over Narrow Band MSK Radio
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Authors:
Shih-Kai Lee, Lu-Ping Keng
Abstract: Narrow band MSK(Minimum Shift Keying) radio is applied for high
receiving sensitive wireless communications like “walky-talky”. iLBC (internet
Low Bit-rate Codec) is widely used in VoIP (Voice over IP) applications like “Skype”.
This paper is concerned with the speech quality by using iLBC in narrow band
MSK wireless communication. Several ULP (Uneven Level Protection) strategies
to protect different part of iLBC coded payloads are evaluated under AWGN
(Additive White Gaussian Noise). We utilize PESQ (Perceptual Evaluation of
Speech Quality) to evaluate the perceptual speech quality. Simulation results
show that significant improvement of PESQ scores are obtained by using
appropriate ULP strategies so that our proposed MSK radio system can also
achieve high receiving sensitivity.
Keywords: MSK, iLBC, VoIP, ULP, PESQ
Title
of the Paper: Multi-carrier Transmission Techniques for Wireless
Communication Systems: A Survey
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Authors:
Haitham J. Taha, M. F. M. Salleh
Abstract: The next generation wireless communications systems require higher
data rates transmission in order to meet the higher demand of quality
services. Research in wireless digital communications techniques have been
expending very rapidly in the last few decades, resulting more reliable
wireless communication systems that operate at higher spectral efficiency.
Since there have been an increased in demand for higher data rate
transmission, the systems are incorporating the multi-carrier transmission
techniques. Therefore, Orthogonal Frequency Division Multiplexing (OFDM) is
one of the leading candidates for future wireless systems. The objective of
the paper is to provide a survey on multi-carrier transmission techniques i.e.
OFDM and the combination of OFDM with Code Division Multiple Access (CDMA).
The review on this rapidly expending area of wireless communication field is
carried out on research works for the past 15 years. And in this survey also
we Trying to explain how to use Discrete Wavelet Transform based OFDM (DWT-OFDM)
Instead of using Fast Fourier Transform based OFDM Fast Fourier Transform
based OFDM (FFT-OFDM). This study outlines the state-of-the art of OFDM novel
technique as well as the methods of multi-carrier - Code Division Multiple
Access (MC-CDMA) and MC- Direct Sequence-CDMA (MC-DS-CDMA).
Keywords: Multi-carrier-CDMA (MC-CDMA), Multi-carrier - Direct Sequence-CDMA
(MC-DS-CDMA)
Title
of the Paper: Large-scale Communication Network Behavior Analysis and
Feature Extraction Using Multiple Motif Pattern Association Rule Mining
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Authors:
Weisong He, Guangmin Hu, Xingmiao Yao
Abstract: Minimize false positive and false negative is one of the difficult
problems of network behavior analysis. This paper propose a large-scale
communications network behavior feature analysis method using multiple motif
pattern association rule mining, analyze multiple behavior feature time series
as a whole, produce valid association rules of abnormal network behavior
feature, characterize the entire communication network security situation
accurately. Experiment with Abilene network data verifies this method.
Keywords: Network behavior analysis, principal components analysis, time
frequency analysis, multiple motif pattern association rule mining
Title
of the Paper: Fast Detection of Specific Information in Voice Signal over
Internet Protocol
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Authors:
Hazem M. El-Bakry, Nikos Mastorakis
Abstract: The world Telecommunications industry caters to both Wireline and
Wireless business. In the present Fourth Generation (4G) wireless world rapid
change is the only constant factor. The biggest paradigm change being the move
from Circuit Switched to Packet Switched technologies. Voice over Packet (VoP)
is transforming telephony by rapidly replacing the legacy circuit-switched
technology. The VoP technology unites the telephony and data worlds allowing
voice, facsimile, and video traffics to be relayed over managed IP networks or
corporate intranets around the world. In this paper, various aspects of Voice
over Internet Protocol (VoIP) are discussed, including the architecture for
the NGMN, challenges, standards and the application areas. In addition a new
approach for fast detecting certain information in VOIP is presented. The
entire data are collected together in a long vector and then tested as a one
input pattern. Proposed fast time delay neural networks (FTDNNs) use cross
correlation in the frequency domain between the tested data and the input
weights of neural networks. It is proved mathematically and practically that
the number of computation steps required for the presented time delay neural
networks is less than that needed by conventional time delay neural networks (CTDNNs).
Simulation results using MATLAB confirm the theoretical computations.
Keywords: Voice over IP, Next Generation Mobile Networks, Fast Information
Detection, Cross Correlation, Frequency Domain
Issue 6, Volume 8,
June 2009
Title
of the Paper: An Adaptive Coded Modulation with Multi-Levels QoS Analysis
in Multimedia Environment
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Authors:
Lamia Chaari, Mohamed Fourati, Nouri Masmoudi, Lotfi Kamoun
Abstract: This article proposes an adaptive coded modulation (ACM) with
multi-levels qualities of service analysis, which can be used to perform
physical layer functions in software radio receivers for beyond third
generation systems. ACM approche employs multiple coding and modulation
schemes in order to adapt instantaneously spectral efficiency to the
signal-to-noise ratio variations SNR. The idea is to study transmission
schemes performance which allow dynamic bandwidth sharing among various
services in multimedia mobile and wireless networks in different channel
environments. The aim is to select the appropriate modulation and channel
coding modes based on signal quality measurement via a decision feedback block
(DFB). Decision taken by the DFB block is based on different QoS parameters
that depend in class and type of multimedia traffic. The DBF block is
introduced in order to mitigate the channel quality fluctuations. The channel
coded adaptive modulation schemes can be viewed as a lower complexity
alternative of mitigating the channel quality fluctuations in comparison to
multiple-transmitter and multiple-receiver. Implementing DFB necessitate to
simulate and analyze different combinations between modulation and channel
coding blocs for different data types.
Keywords: Channel coding, adaptive modulation, Signaling, image, Multimedia, SDR
Title
of the Paper: Selection Combining Receiver in the Presence of Ricean Fading
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Authors:
Petar Spalevic, Mihajlo Stefanovic, Dusan Stefanovic, Stefan Panic
Abstract: This paper focuses on comparing performances of the selection
combining (SC) diversity system in the presence of independent and correlated
Ricean fading. For the case of correlated fading, we have presented closed
form expressions for probability density function (PDF), and cumulative
density function (CDF), at the output of dual branch SC. Also we have
presented closed form expressions for system performances such as: average bit
error-rate (ABER), outage probability (OP) and average output moments, which
is the main contribution of our work. For the case of independent fading
between the diversity branches, we have analyzed performances of SC diversity
system which consists of two and four input branches. All obtained results are
graphically presented.
Keywords: Ricean fading, Selection combining, System performances
Title
of the Paper: Multiple Selection Diversity over Exponentially Correlated
Nakagami-m Fading Channels in the Presence of Cochannel Interference
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Authors:
Dragana Krstic, Stefan Panic, Aleksandar Mosic, Mihajlo Stefanovic
Abstract: The system performances of selection combining over exponentially
correlated Nakagami-m channels are analyzed in this paper. Selection diversity
based on the signal to interference ratio (SIR) is very efficient technique
that reduces fading and cochannel interference influence. Fading between
diversity branches and between interferers is correlated and Nakagami-m
distributed with exponential correlation model. Very useful closed-form
expressions for the output SIR’s probability density function (PDF),
cumulative distribution function (CDF), and outage probability are obtained,
which are the main contributions of this paper. Also, the conclusions about
influence of fading severity and correlations between received desired signals
and interferences on the system performances, such as outage probability,
average-output SIR and amount of fading (AoF), are presented.
Keywords: Cochannel Interference; Signal to Interference Ratio (SIR);
Exponential Correlated Nakagami-m fading; Selection Combinig
Title
of the Paper: Adaptive Estimation/Compensation Scheme of IQ Imbalance with
Frequency Offset in Communication Receivers
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Authors:
Yi-Jen Chiu, Chien-Sheng Chen, Shao-Ping Hung
Abstract: IQ signal processing is widely utilized in today’s communication
system. However, it usually faces a common problem of front-end distortion
such as IQ imbalance and frequency offset. Effective algorithms exist for
estimating and compensating for IQ imbalance as well as frequency offset, when
the two problems are treated separately. With both effects present, such
algorithms do not lead to useful estimates of the related parameters. In this
paper, we propose a robust technique to estimate and compensate for the IQ
imbalance in the presence of carry frequency offset (CFO) by using a known
preamble of repeated training sequence. In addition, to solve the problem of
performance degradation when CFO is small we developed an adaptive scheme with
small residual degradations. The performance of such a scheme has been
validated by computer simulations on IEEE 802.11a signals. And it is shown
that the proposed method is more robust and renders better performance than
existing algorithm.
Keywords: IQ imbalance, carrier frequency offset (CFO), IEEE 802.11a
Title
of the Paper: Using Concepts of Control Charts to Establish the Index of
Evaluation for Test Quality
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Authors:
Chiu-Yao Ting, Chwen-Tzeng Su
Abstract: The purpose of this research employs concepts of control charts to
establish a new evaluation standard for a test quality index. First, this
study establishes criteria for assessing test quality by exploring the item
discrimination index (D) in the general test areas. Further, data of this one
index are normalized, and standard deviation is applied for the control limit
of the control chart. Thus, the zone rules for the standardized D (SD) control
chart proposed in this study are found to be an excellent evaluation method
for test quality from the perspective of control charts.
Keywords: Test quality, control charts, item discrimination, standard deviation,
control limit, zone rules
Issue 7, Volume 8,
July 2009
Title
of the Paper: An Adaptive Cross-layer Bandwidth Scheduling Strategy for the
Speed-Sensitive Strategy in Hierarchical Cellular Networks
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Authors:
Jong-Shin Chen, Mei-Wen Li, Neng-Chung Wang, Yung-Fa Huang
Abstract: Efficient bandwidth scheduling of wireless bandwidth is critical to
cellular system performance. Bandwidth scheduling methods can be divided into
cell-layer channel allocation and call-layer channel assignment. Previous
studies are focused on the latter type of method. Some problems, such as
traffic-load variations among base stations (BSs) and BSs failed to provide
wireless communication service, are the cell-layer problems and are difficult
to handle using the call-layer methods. Therefore, this study presents an
adaptive cross-layer bandwidth scheduling strategy for hierarchical cellular
networks. This strategy is implemented to solve the traffic-adaptation and the
fault tolerance problem according to the speed-sensitive call-layer method.
Keywords: Cross-layer, speed sensing, traffic adaptation, and fault tolerance
Title
of the Paper: Cross-Layer Design and Performance Analysis of TDMA-based
Backhaul Network
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Authors:
Rashid A. Saeed, Zulkalnain Mohd Yusof, Anuar Bin Musa
Abstract: The needs for bridging of digital divide in rural communities and
the economics of currently available broadband access technologies motivate
for innovate and deploy new system designs and applications. The widely
available and flexible WiFi technique meets the cost and suitability targets
for rural broadband applications. To cope with the special requirements of
rural communication, amendments of 802.11 standards at the MAC protocol level
has been introduced. These amendments were important due to the shortcomings
of WiFi over long distances under the power constraints. This paper proposes a
new 802.11 point-to-multipoint (PMP) technique based on TDD/TDMA technique,
this by using one of the access points in the system as centralized/gateway
point to the others APs. The discussion includes the TDMA design, architecture
on top of the conventional 802.11 MAC. The protocol convergence at the gateway
between the access network and the backhaul is also presented. The simulation
results present the performance analysis and validate the efficiency of the
proposed scheme.
Keywords: Point-to-multipoint (PMP), TDMA, MAC, 802.11 WiFi, rural
communications, Cross-Layer Design, WiMAX, network allocation vector
Title
of the Paper: Performance Improvement of Double-Layer Networks with
Holographic Optical Switches
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Authors:
Chi-Ping Lee, Chien-Ping Chang, Jiun-Shiou Deng, Ming-Feng Lu, Yang-Tung
Huang
Abstract: In our previous research, combining the unique features of the
double-layer network and holographic optical switches not only reduces the
volume of the whole system and eliminates all interconnection lines and
crossovers significantly, but also reduces the number of drivers from
N2/4+2Nlog2N-2N to 2Nlog2N. In this paper, modifying the structures of the
holographic optical switches to satisfy the characteristics of the
double-layer network, the system insertion loss can be minimized significantly
from (2log2N-1)(LPBS+2LEOHWP) to (2log2N-2)LPBS+2(log2N)LEOHWP (dB). After
rearranging the channels, the number of electro-optic halfwave plates can be
decreased significantly from 2N2-2N to 2Nlog2N.
Keywords: Holographic optical switch, polarization beam splitter, double-layer
network, optical interconnection network, system insertion loss,
signal-to-noise ratio
Title
of the Paper: Hopfield Neural Network for UWB Multiuser Detection
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Authors:
Chia-Hsin Cheng, Guo-Jun Wen, Yung-Fa Huang
Abstract: The Hopfield neural network (HNN) is introduced in the paper and is
proposed as an effective multiuser detection in direct sequence-ultra-wideband
(DS-UWB) systems. It can approximate to maximum likelihood (ML) detector by
mathematical analysis. According to the HNN-based technique, the computer
simulation results show that they have good performances and much lower
computational complexity in a multiuser environment.
Keywords: Maximum likelihood, Neural network, Hopfield
Title
of the Paper: An Adaptive Load Balance Allocation Strategy for Small
Antenna Based Wireless Networks
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Authors:
Jong-Shin Chen, Neng-Chung Wang, Zeng-Wen Hong, Young-Wei Chang
Abstract: Technological advances and rapid development in handheld wireless
terminals have facilitated the rapid growth of wireless communications. Since
this tremendous growth of wireless communication requirements is expected
under the constraint of limited bandwidth. The small antenna frameworks that
can provide more flexible to handle the limited bandwidth will be the
mainstream for wireless networks. The antenna divided a cell into several
sections. Each section contains a part of the system codes used to provide
wireless communications. Therefore, the system codes allocated to each section
will effect the system capacity and a reasonable allocation should provide
more codes to a section with heavy traffic than a section with light traffic.
However, the large number of sections increases the difficult to allocate
system codes to sections. Especially, when there are variations in the traffic
loads among sections will lessen the traffic-carrying capacity. This study
proposes an adaptive load balance allocation strategy for small antenna based
wireless networks. This strategy is implemented to solve traffic-adaptation
problem that can enhance the traffic-carrying capacity for variations in
traffic. Furthermore, the simulation results are presented to confirm the
efficiency of the proposed strategy.
Keywords: Small antenna, wireless network, load balance, and traffic-adaptation
Title
of the Paper: Fast Convergence Algorithm for Decoding of Low Density Parity
Check Codes
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Authors:
Jin Xie, Liuguo Yin, Ning Ge, Jianhua Lu
Abstract: In this paper, a fast-convergence algorithm is proposed for the
decoding of low-density parity-check (LDPC) codes. By putting more weight on
the message update from check node to variable node in current iteration, the
proposed method speeds up the decoding significantly. Simulation results show
that compared with the standard layered min-sum decoding algorithm, the
proposed scheme may reduce about 1/6 iteration numbers for LDPC codes used in
DVB-S2, with hardware complexity overhead less than 2%.
Keywords: LDPC code, fast convergence decoding algorithm, layered decoding,
min-sum algorithm, hardware implementation
Title
of the Paper: New Code Construction Method and High-Speed VLSI Codec
Architecture for Repeat-Accumulate Codes
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Authors:
Kaibin Zhang, Liuguo Yin, Jianhua Lu
Abstract: Repeat-Accumulate code has been widely used in various practical
communication systems due to its special structure that can be encoded with a
low complexity turbo-like encoder and decoded with a high-speed parallel
algorithm. However, the construction of RA codes with large girth is still a
challenging problem. In this paper, the girth upper bound of RA codes is
analyzed and a novel RA code construction scheme is proposed. This scheme
generates the parity-check matrix with superimposed structured interleavers,
guaranteeing the resulting matrix to be globally optimized. Compared with the
RA codes constructed with traditional structured interleavers such as
?-rotation interleavers, pseudo-random interleavers, combinatorial
interleavers, and modified L-type interleavers, the codes constructed with the
proposed method exhibit better error-correcting performance. Moreover, a
parallel VLSI codec architecture is proposed for the RA codes generated with
the proposed method in this paper. Modifying the conventional RA encoder
architecture, the codec for RA codes from our proposed method may have the
same hardware implementation complexity as that for traditional RA codes,
while the data throughput of our codec may achieve up to 450Mbps, which may be
of great value for practical applications.
Keywords: Repeat-Accumulate (RA) codes, low-density parity-check (LDPC) codes,
superimposed structured interleaver (SSI), hardware implementation
Title
of the Paper: A New Method for Indoor Location Base on Radio Frequency
Identification
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Authors:
Rung-Ching Chen, Sheng-Ling Huang
Abstract: In recent years, there has dramatic proliferation of research
concerned with Radio Frequency Identification (RFID). The RFID technologies
are getting considerable attentions not only academic research but also the
applications of enterprise. One of most important issues of applications is
the indoor position location. Many researchers have used varied technologies
to perform the tracking of indoor position location. In this paper, we will
purpose a new method using RFID tags to perform indoor position location
tracking, too. This method uses Received Signal Strength (RSS) to collect
signal strength from reference tags beforehand. Next, signal strength is used
to set up Power Level areas of ranges by reference tags. And then, using
signal strength from reference tags to match signal strength by track tags.
Finally, when track tags is set up into indoor environments, it will find out
the position of neighboring reference tags, and using arithmetic mean to
calculate the location values. A preliminary experiment proves that our method
provides a better precision than LANDMRC system.
Keywords: RFID, indoor position location, RSS, Powel Level, location
identification, LANDMRC
Title
of the Paper: Design and Analysis of New Digital Modulation Classification
Method
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Authors:
Anna Kubankova
Abstract: In this paper, a new method of digital modulation classification is
described. The method was applied to signals with FSK, BPSK, MSK, QAM-16 and
QPSK modulations. The spectrogram analysis was used for the modulation type
recognition. This classification method was examined on signals corrupted by
Gaussian noise, phase noise and on signals after their transmission through
multipath Rayleigh fading channel. The Matlab program is used for the
analysis.
Keywords: Digital modulation, Classification, Spectrogram, Modulation
recognition, noise, interference
Title
of the Paper: Using Simulated Annealing Algorithm for Maximizing Social
Utility in Dynamic Spectrum Management
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Authors:
Yu-Cheng Lin, Ming-Hua Lin, Hsin-Hsiung Huang, Lu-Yao Lee
Abstract: Thousands of equipments of the wireless local access network and the
mobile devices are widely used and the demand of dynamic spectrum resources is
significantly growing. How to maximize the social utility in modern technique
becomes an important issue. In this paper, the simulated annealing based
approach which dynamically allocates the power spectrum is proposed to enhance
the system efficiency. The objective is to maximize the sum of individual
Shannon utilities in a multi-user communication system. Experimental result
shows that our approach obtains the acceptable result within an acceptable
amount of run time for the larger test cases.
Keywords: Simulated annealing, Social utility maximization, Shannon utility,
Dynamic spectrum management, Multi-user communication system, Power spectrum
Title
of the Paper: Study on the Technology of Tracking Noise Jamming with
Monopulse Radar and Analysis on its Tracking Errors
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Authors:
Yanhua Zhang, Zhongjie Zhang, Jian Wang
Abstract: Under self-protecting noise jamming, mono-pulse radar can track the
target by tracking noise jamming because noise jamming comes from the same
direction as echo of target. In order to reduce angular tracking error, a
method of introducing pulse modulation circuit and adjusting the bandwidth of
intermediate frequency amplifier and video amplifier is proposed based on the
main causes of angular error. Simulation studies verifies its effectiveness.
In order to solve the problem of arranging stations in direction-finding
cross-location technology, a method of station distribution arrangement is put
forward based on the principle analysis of direction finding location with two
stations. The receiving angle range to achieve higher location accuracy and
the distance between two stations to meet the range of receiving angle are
chosen. At last the easier calculation method of location accuracy in passive
tracking is given. The studies show that the proposed methods can effectively
improve tracking accuracy in tracking noise jamming with mono-pulse.
Keywords: Noise jamming, Mono-pulse radar, Angular error, Cross-location,
Arrangement, Tracking error
Title
of the Paper: A Forwarding Station Integrated the Low Energy Adaptive
Clustering Hierarchy in Ad-hoc Wireless Sensor Networks
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Authors:
Chao-Shui Lin, Ching-Mu Chen, Tung-Jung Chan, Tsair-Rong Chen
Abstract: An ad-hoc wireless sensor network is also called self-organized
networking that wireless sensor nodes can automatically communicate for each
other. Therefore, each sensor node is no need for the information such as
location of each sensor. Similarly, it consumes much energy on the information
exchanged of each sensor node in order to maintain the entire ad-hoc wireless
sensor network alive. Therefore, there are totally three phases in this paper.
First, the setup phase is that all sensor nodes are randomly deployed and the
ad-hoc wireless sensor network is divided into many clusters in each round.
Therefore, every cluster has only one cluster head. Second, each sensor node
transmits its message to the cluster head where it belongs to and then the
cluster head transmits the messages coming from sensor nodes and deliver it to
forwarding station. Finally, the forwarding station forwards the integrated
messages from all cluster heads back to the base station. However, it consumes
less energy for all cluster heads to transmit directly back to the base
station. Hence, the far away location of the base station usually consumes the
cluster head much energy to transmit the message to the base station. With the
proposed three-phase scheme, the ad-hoc wireless network lifetime can be
extended very well. Also, the simulation results show the entire ad-hoc
wireless network lifetime can be extended very well.
Keywords: Ad-hoc Wireless sensor networks, Network lifetime, Three-phase scheme,
Forwarding station, Self-organized, Cluster
Title
of the Paper: Successive Interference Cancellation for Optical CDMA
Systems: Fundamental Principles
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Authors:
Tawfig Eltaif, Hossam M. H. Shalaby, Sahbudin Shaari, Mohammad M. N.
Hamarsheh
Abstract: In this paper successive interference cancellation (SIC) based on
optical code division multiple access (O-CDMA) systems has been investigated.
SIC scheme refers to a family of low complexity multi-user detection (MUD)
methods for direct sequence CDMA systems. Performance of optical CDMA system
is influenced by multiple access interference (MAI) resulted from the
overlapping between the users. This kind of noise is became a primary concern
in optical CDMA systems. To overcome this problem, we applied successive
interference cancellation technique to a spectral amplitude coding (SAC)
system that uses modified quadratic congruence (MQC) codes as signature
sequence codes, taking into account the effect of all major noise sources,
such as phase-induced intensity noise (PIIN), shot noise, and thermal noises.
Furthermore, in SIC scheme we have taken into account the impact of imperfect
interference cancellation. The system is analyzed for two cases: same
effective power for all the users and different effective power from each
user. We have successfully shown that under ideal effective power the SIC/SAC
optical CDMA systems have potential to suppress the intensity noise and
mitigate multiple access interference. Hence, using SIC/SAC cancellation
scheme, the system can accommodate much more number of users as compared to
the one without cancellation. Further, under ideal power the system using SIC
scheme with direct sequence encoding (SIC/DS) shows much lower BER performance
as compared to the one without cancellation (i.e. conventional receiver) or to
SIC/SAC cancellation scheme. Hence, much more number of users can be
accommodated by SIC/DS receiver system. Furthermore, SIC/DS scheme still shows
much lower BER performance as compared with SIC/SAC scheme under different
effective power.
Keywords: Optical code division multiple access (O-CDMA); successive
interference cancellation (SIC); spectral amplitude coding (SAC); multiple
access interference (MAI); modified quadratic congruence (MQC)
Title
of the Paper: Simulation and Applications of Nonlinear Fiber Bragg Gratings
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Authors:
Farzin Emami, Amir H. Jafari
Abstract: We have simulated the behaviors of nonlinear fiber Bragg gratings (FBGs).
The generalized nonlinear equations governing these structures are solved by a
method which uses a Fourier series procedure and a simple iterative method.
All of the nonlinear effects are considered. Bragg soliton generation in
intrinsic media and birefringence effects in FBGs are studied. We found that
the first order dispersion can causes time shifting in the input pulse peak.
It is shown that FBGs are proper for optical switching too. They can use in
filters, nonlinear fiber optical applications, soliton propagations etc.
Keywords: Nonlinear Fiber Bragg gratings, Modulation intensity, Solitons,
Birefringence, Optical switches, Simulation
Title
of the Paper: The First Millimeter-wave Point-to-Point Wireless Gigabit
Ethernet Communication System at TMR&D
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Authors:
Azzemi Ariffin, Young Chul Lee, Mohd. Fadzil Amiruddin, Suhandi Bujang,
Salizul Jaafar, Noor Aisyah Mohd. Akib
Abstract: In this paper, a millimeter-wave point-to-point (PTP) Wireless
Gigabit Ethernet Communication System is presented and the first been
developed by TMR&D. A 60 GHz Low Temperature Co-Fired Ceramics (LTCC)
System-On-Package (SoP) Transceiver capable of gigabit data rate has been
built and demonstrated with a size of 17.76 x 17.89 mm2. A direct
Amplitude-Shift Keying (ASK) modulation and demodulation scheme is adopted for
the 60GHz-band transceiver. A BER of 1?10-12 for data rate of 1.25
gigabit-per-second (Gbps) on 2.2 GHz bandwidth at 1.4 km was demonstrated.
This paper reports a new PTP link that has been installed at TMR&D site to
demonstrate wireless gigabit operation and performance of its key components.
The link will operate at the 57.65-63.35 GHz band incorporating TMR&D’s
designed millimeter-wave LTCC SoP RF Transceiver module. This LTCC SoP RF
Transceiver is suitable for short-range wireless networking systems, security
camera TV, video conferencing, streaming video like HDTV (high definition
television) and wireless downloading systems for small power application.
Outdoor wireless link test shows that the transmission range of PTP system
using the SoP Transceiver is 1.4 km.
Keywords: PTP link, Wireless gigabit, LTCC, SoP, RF Transceiver
Title
of the Paper: Social Networks and Job Satisfaction of Nurses
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Authors:
Hsieh-Hua Yang, Yi-Horng Lai, Wan-Ching Chao, Shu-Fen Chen, Mei-Hua Wang
Abstract: The research examines the relationship between propensity to connect
with others, social networks and job satisfaction. Social networks serve as a
social resource which affects job satisfaction through the provision of
supportiveness. The characteristics of nursing are life-related and
emotion-consumed job. It is argued that both advice and friendship networks
are important in a work setting. The research team developed a questionnaire
and administered during an on-job training of the nurses. To derive the
participants’ advice and friendship networks, they were asked to list the
names whom they consulted when they needed to know something about work and
whom they considered to be their friends. Job satisfaction and the propensity
to connect with others were also measured. The results showed that propensity
to make acquaintance and outdegree were correlated with job satisfaction. Most
of all, the advice and friendship networks were partially overlapped. It was
concluded that the human resource professional shoud care about both formal
and informal relationships.
Keywords: Social networks, nurses, propensity to connect with others, job
satisfaction, advice network, friendship network
Title
of the Paper: WiMAX Integration in NGN Network, Architecture, Protocols and
Services
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Authors:
Arianit
Maraj, Ilir Imeri
Abstract: With growing demands for fast provision of new and complex services,
imposed by life and business dynamic in general, service providers are forced
to adopt open technologies and advanced business models in their solutions.
These enable a fast response to market demands and maximum utilization of the
network. A big challenge for operators today is how to deliver broadband
services in rural areas. Today, the broadband services in urban areas are
served by DSL and cable modems. However, it is too difficult and very
expensive for operators to deploy wired network in rural areas. BWA technology
can overcome this problem. Today, the most popular BWA technology is WiMAX
(commonly referred as IEEE 802.16), which supports fixed, nomadic, portable,
and mobile operations. WiMAX is based on IP network. As a result, many
operators around the world are interested to integrate WiMAX in existing
networks to facilitate the move to an all IP.
Keywords: Integration, WiMAX technology, NGN network, protocols, security
Title
of the Paper: Optimal Combining, Partial Cancellation, and Channel
Estimation and Correlation in DS-CDMA Systems Employing the Generalized
Detector
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Authors:
Vyacheslav Tuzlukov
Abstract: The symbol-error rate (SER) of a quadrature subbranch hybrid
selection/maximal-ratio combining scheme for 1-D modulations in Rayleigh
fading under employment of the generalized detector (GD), which is constructed
based on the generalized approach to signal processing in noise, is
investigated. At the GD, N dive-rsity branches are split into 2N in-phase and
quadrature subbranches. Traditional hybrid selection/maximal-ratio combining
is then applied over 2N subbranches. M-ary pulse amplitude modulation,
including coherent bi-nary phase-shift keying (BPSK), with quadrature
subbranch hybrid selection/maximal-ratio combining is investigat-ed. The SER
performance of the GD under quadrature subbranch hybrid
selection/maximal-ratio combining and hybrid selection/maximal-ratio combining
schemes are investigated and compared with the conventional hybrid
selection/maximal-ratio combining receivers. The obtained results show that
the GD with quadrature su-bbranch hybrid selection/maximal-ratio combining and
hybrid selection/maximal-ratio combining schemes out-perform the traditional
hybrid selection/maximal-ratio combining receiver. Procedure of selecting the
partial cancellation factor for the first stage of a hard-decision partial
parallel interference cancellation of the GD emp-loying in direct-sequence
code-division multiple access (DS-CDMA) systems is proposed. A range of the
opti-mal partial cancellation factor, where the lower and upper boundary
values can be explicitly calculated from the processing gain and the number of
users of the DS-CDMA system, is derived based on the Price’s theorem. Co-mputer
simulation results confirmed that, using the average of these two boundary
values as the partial cancell-ation factor for the first stage, we are able to
reach the bit error rate (BER) performance that is very close to the
potentially achieved BER performance using the GD and surpasses the BER
performance of the real partial ca-ncellation factor for DS-CDMA systems
discussed in literature. Channel estimation errors have to be taken into
account under analysis of receiver in order to the system performance will be
not degraded under practical cha-nnel estimation. In this paper, we propose
the GD, which takes the estimation error of maximum likelihood (ML)
multiple-input multiple-output (MIMO) channel estimation and receiver
spatially correlation into account in computation of the minimum mean square
error (MMSE) GD and log-likelihood ratio (LLR) of each coded bit. Comparative
analysis and simulation results show that the proposed MMSE GD can obtain
sizable perform-ance gain and outperforms the existing soft-output MMSE
vertical Bell Lab Space Time (V-BLAST) detector and its modification versions.
Keywords: Generalized detector, Diversity combining, Symbol error rate, Fading
channel, Hybrid selection/ maximal-ratio combining, Partial cancellation
factor
Title
of the Paper: RFID Encryption/Decryption Technology Aided Multimedia and
Data Intellectual Property Protection
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Authors:
Ming-Shen Jian, Ta-Yuan Chou, Shu Hui Hsu
Abstract: In this paper, a RFID Encryption/Decryption Technology Aided
Multimedia and Data Intellectual Property Protection is proposed. The
encryption code for each multimedia or data is embedded in the existing
encryption algorithm. Furthermore, the unique ID of RFID tag can guarantee the
legality of each RFID tag. Two types of RFID tag is implemented for
multimedia/digital content and normal user. The encryption code is recorded
and locked in the data slot of RFID tag which embedded in the digital content
storage hardware. Only normal user provides the corect RFID tag with legal key
for unlocking thedata slot, he encryption code can be gained. The verification
shows the proposed technology is realistic and only users who have the legal
RFID tag can gain the digital multimedia content.
Keywords: RFID, Multimedia, Intellectual Property, Digital Label, System
Integration
Issue 8, Volume 8,
August 2009
Title
of the Paper: Extended Kalman Filtering and Phase Detector Modeling for a
Digital Phase-Locked Loop
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Authors:
Tsai-Sheng Kao, Sheng-Chih Chen, Yuan-Chang Chang, Sheng-Yun Hou,
Chang-Jung Juan
Abstract: The realization of a digital phase-locked loop (DPLL) requires to
choose a suitable phase detector and to design an appropriate loop filter;
these tasks are commonly nontrivial in most applications. In this paper, the
phase detector is examined, and a simple model is given to describe the
characteristics of the timing function. The DPLL system is then formulated as
a state estimation problem; then an extended Kalman filter (EKF) is applied to
realize this DPLL for estimating the sampling phase. Therefore, the phase
detector and loop filter are simply realized by the EKF. The proposed DPLL has
a simple structure and low realization complexity. Computer simulations for a
conventional DPLL system are given to compare with those for the proposed
timing recovery system. Simulation results indicate that the proposed
realization can estimate the input phase rapidly without causing a large
jittering.
Keywords: Digital phase-locked loop (DPLL), phase detector, state estimation,
extended Kalman filter (EKF)
Title
of the Paper: Multiband Antenna for Low-Frequency Radio Telescope
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Authors:
Radial Anwar, Norbahiah Misran, Mohammad Tariqul Islam, Geri Gopir
Abstract: Radio astronomical instrumentation has become a fascinating field of
research in astronomy. In this paper, a design of multiband novel antenna for
low-frequency radio telescope is proposed. The multiband has been achieved by
combining V-shape half-wavelength dipole, traps and parasitic elements. The
low return loss, multiband and maximum gain within the zenith direction is
provided by V-shape half-wavelength dipole, traps and parasitic elements
respectively. The study showed return loss of about -20 dB, -17 dB and -13.6
dB for three different frequencies with maximum achievable gain of about 10.28
dBi. Measurement result shows that the proposed antenna can work properly and
meet well to be used in a transient radio telescope which is operated in the
urban centers.
Keywords: Radio Telescope, V-shape Antenna, Trap, Parasitic Element
Title
of the Paper: Inter-Channel Interference Cancellation in Wireless Mesh
Network
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Authors:
Wadhah Al-Mandhari, Nobuo Nakajima
Abstract: Interference is one of the challenges that limit the performance of
Wireless Mesh Networks (WMN). It became a major issue with new devises being
equipped with more than one radio interface. This research emphasizes on
impact of interference in multi-hop/ multi-radio WMN’s throughput as a result
of utilizing dual radios in WMN’s station. Various laboratory experiments in
this research indicates that the IEEE802.11 noninterfering channels for the
2.4GHz band still exhibit some level of interference. Furthermore, we proposed
an interference cancellation circuit that showed a noticeable throughput
enhancement in our experiments. This validates the proposed solution for
interference suppression and throughput enhancement.
Keywords: Wireless Mesh Network (WMN), Access point (AP), Netperf, Signal to
Interference Ratio (SIR), Non-overlapping channels, UDP throughput
Title
of the Paper: GIS Supporting the Plan of BTS (Base Transceiver Stations)
for Mobile Network in Urban Context
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Authors:
Vincenzo Barrile, Giuseppe Armocida, Giuliana Bilotta
Abstract: In recent years the technological development in general and the
spread on the territory of antennas for mobile phones urged a state of
widespread public concern repeatedly verging the social alarm. The need for a
greater territorial coverage of mobile telephone service, due to the
continuous request of users and to the presence of more operators in the
market, led an intensification of the installations that not only made to a
progressive decrease the power radiated from individual installations, it also
required that they be placed closer to homes with consequent concern of the
population for their own health. It is known that for assessing the levels of
electromagnetic field in a particular place or around a given source (thus
assessing the potential risk for the population nearby living) should be
campaigns to measure or apply the theoretical methods (analytical or
numerical). The Municipality of Reggio Calabria in 2006 started a project
having as its main purpose the development of a GIS (Geographic Information
System), capable of "storing" the results of measurement campaigns and also to
apply a theoretical model for developing scenarios of exposure to
electromagnetic field. The aim is to assess whether the presence of fixed
installations for cellular phone is compatible with the health of citizens, or
if the values of exposure to electromagnetic fields produced by them are
within the limits set by law. This was achieved through the implementation of
a Geographical Information System able to manage, store, process all data
(both alphanumeric that geographical) relating to devices GSM, GPRS, UMTS with
also the possibility to update the database (Technical data characteristics
antennas) and insert new installations. In addition to the management, GIS is
able to calculate the electromagnetic field produced by the antennas. The SIT
is therefore the final collector, performing in a single "container" the
stacking phase and the monitoring of electromagnetic radiation (in operational
band of GSM, GPRS, UMTS), and finally support the phases related to the
remediation of areas with anomalous values of the electromagnetic field, thus
supporting the planning phase of the distribution of antennas in urban
context.
Keywords: Electromagnetic fields – Base Transceiver Stations – Mobile
Communications – Model for calculating EF – Geographical Information Systems
Title
of the Paper: Study Cases on eLearning Technologies Used by Universities in
Romania and Worldwide
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Authors:
Iasmina Ermalai, Diana Andone, Radu Vasiu
Abstract: eLearning is a term broadly used to describe the process of learning
with the use of informational technologies and tools, usually through a web
page. Nowadays it is hard to speak about eLearning without implicitly
including an eLearning management system and new informational technologies. A
learning management system (LMS or LCMS) is used to deliver educational
material and manage interaction between students and tutors. LMSs can be open
source, commercial or developed in-house by the universities. Tools like
audio/ video conferencing, streaming, podcasting, social software, RSS feeds,
can be incorporated into the LMS or can be subsequently added to the learning
system as individual modules. This present paper seeks to establish the
current state of eLearning technologies, both worldwide as well as in Romania.
Keywords: LMS, CMS, LCMS, VLE, eLearning, informational technologies, podcasting,
RSS
Title
of the Paper: A Local Information Based Protocol for Networks Data Exchange
with Application to Mobile Sensor Networks
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Authors:
Paolo Di Giamberardino, Ivano Bergamaschi, Andrea Usai
Abstract: The paper presents a new protocol for multi hop data transmission
between nodes in a mobile sensor network. The only requirement for the network
is to be connected. The routing is handled locally on the basis of
informations contained in the data transmitted. Global (time dependent)
routing table as well as knowledge on the position of the nodes are not
required, since the protocol itself contains an Hand-Shake phase for the
neighbour detection. This allow to have high mobility for the nodes and,
moreover, it is dynamically reconfigurable once the number of the nodes
varies. A innovative data structure called “the Postman Bag” is introduced to
spread data collected by sensor quickly and simply. Some considerations about
the computational complexity and the performances of the proposed approach are
reported on the basis of some simulations and some initial tests on small
dimension networks.
Keywords: Mobile sensor network, Data transmission, Protocol, Wireless
communications, Local management, Dynamic reconfiguration
Title
of the Paper: A Compositional Technique for Hand Posture Recognition: New
Results
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Authors:
Georgiana Simion, Vasile Gui, Marius Otesteanu
Abstract: New results obtain with the compositional technique for hand posture
recognition is presented. Compositional methods are a powerful approach in
image understanding. Most papers using this concept address image
categorization problems. We recently propose a hand pose recognition method
using the compositional approach. In this paper we present further development
of our method and new results.
Keywords: Compositional technique, hand posture recognition, sparse, clustering
Title
of the Paper: Dimensioning Rules Regarding Radio Resources in GSM/GPRS
Networks
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Authors:
Cornel Balint, Georgeta Budura, Adrian Budura, Eugen Marza
Abstract: Many works have studied traffic modeling in GSM/GPRS networks trying
to establish different performance parameters needed for dimensioning
purposes. An important element of these networks is the radio resources.
Sharing resources between different users and different services is a key
concept of radio resources dimensioning in GSM/GPRS networks. In this paper we
focus on the problem of performance evaluation in GSM/GPRS networks. We
consider different resources allocation strategies such as: CP (Complete
Partitioning) and PP (Partial Partitioning) and we study the influence of
different operational details concerning TS (time-slots) assignment: FR (full
rate), HR (half rate) and packing. Finally, we establish dimensioning rules
based on traffic evaluation and quality of service level for GSM/GPRS users.
For voice users the quality of service is given by the blocking probability
calculated according to the proposed packing rule and for GPRS users the
individual throughput and the blocking probability represent the performance
parameters. We consider also the preemption probability of voice over data
users.
Keywords: GSM/GPRS, modeling, Erlang-B law, packing, blocking probability,
Engset law, throughput
Title
of the Paper: Traffic Models and Associated Parameters in GSM/(E)GPRS
Networks
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Authors:
Georgeta Budura, Cornel Balint, Adrian Budura, Eugen Marza
Abstract: GSM/(E)GPRS networks support a mixture of traffic consisting of
voice and data. A key concept of dimensioning radio resources in such networks
is represented by sharing resources between different users and different
services. In this paper we address the problem of voice and data traffic
models according to different resources allocations strategies: CP (Complete
Partitioning) and PP( Partial Partitioning) and define specific parameters in
each case. The proposed traffic model depend in each case on the resources
allocation strategy: for voice traffic it is based on both cases, CP and PP,
on Erlang law meanwhile for data traffic we build different models depending
the scheme used for resources allocation. For CP scheme we propose two models:
the model based on Erlang law and those based on modified Engset law. For PP
scheme we also proposed two models: one is based on the bi-dimensional Markov
chain and the other on the modified Engset law. Both consider voice-data
interaction according to the PP scheme. In all cases we define specific
performance parameters. We also implement the studied models and evaluate the
proposed performance parameters. Finally we compare the results in order to
find the adequate model to use for dimensioning purposes.
Keywords: GSM/(E)GPRS, blocking and preemption probability, Erlang-B law, Engset
law, average throughput, cell utilization
Title
of the Paper: Design of Switched Multiband Filters for IEEE 802.11a/b/g
WLANs
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Authors:
S. Raghavan, Sion. P
Abstract: Switched Multiband Microstrip bandpass filters for IEEE 802.11a/b/g
WLANs are presented. Cross coupled square open loop resonator type of filter
is used as the basic design. These filters were selected since there was a
tuning parameter available in the structure which changed the center frequency
without change in performance. Two MEMS reconfigurable filter structures are
proposed. Static simulations for each position of the MEMS switches were
performed for S11 and S12 to observe the bandwidth and insertion loss of the
filter. The simulations were performed on IE3D 10.06.
Keywords: WLAN, MEMS, ISM, UNII, Microstrip Filter
Title
of the Paper: Microstrip Patch Antenna for a Retinal Prosthesis and RF MEMS
Technology
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Authors:
S. Raghavan, G. Anantha Kumar
Abstract: This paper is about the investigation of a novel approach for
establishing a data telemetry link in a dual-unit retinal prosthesis at
microwave frequencies (1.4GHz and 2.35GHz) using a pair of Microstrip patch
antennas. Approximately sized extraocular (25 mm x 25 mm) and intraocular (6
mm x 6 mm) antennas are simulated using IE3D and compared with reference
experimental results which was designed and fabricated using the Finite
Difference Time Domain Method. Simulation results show frequency shift in the
resonant frequency by changing the capacitor height from 2 μm to 1 μm.
However, the major drawback of this configuration is as Microstrip antenna is
loaded with radial stub, which makes the structure is not suitable for loading
with large number of capacitors. Because the dimensions of the radial stub
determine the separation between the MEMS capacitors. Hence, the overall
dimensions of the structure grow as more MEMS capacitors are used for loading,
which is a problematic issue in terms of fabrication.
Keywords: Epiretinal, Subretinal, Telemetry link, Retinal Prosthesis
Title
of the Paper: Design of Planar Inverted -F Antenna for Wireless
Applications
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Authors:
S. Raghavan, N. Jayanthi
Abstract: The design of single feed dual band PIFA operating at 2.25and 3.546
GHz is presented. Two dimensional method of moments (MOM) electromagnetic
simulator, IE3D version: 12, is used in the design simulation of this dual
band antenna. The results exhibit a proper operation of the antenna in terms
of return loss, bandwidth, efficiency, gain at both bands.ISM,Bluetooth,Wi-max,
IEEE 802.11b, 802.11g, 802.11n, 802.16e, WiFi, Wi-max are the most important
applications within the above mentioned frequency bands. Simulation tool,
based on the method of moments (ZELAND IE3D version 12.0) has been used to
analyze and optimize the antenna. The measured and simulated results are
presented and all are acceptable to the standard antennas.
Keywords: ISM, Bluetooth, Wi-max, PIFA, Method of Moments, NLOS, WiFi
Title
of the Paper: Fusion of Technology in Analysis, Design and Comparison of
Numerical Techniques for Rectangular Microstrip Patch Antenna
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Authors:
S. Raghavan, T. Shanmuganantham
Abstract: In today’s scenario higher integration and smaller layout size are
the two major trends in RF and Microwave industry, lead to more prominent role
in electromagnetic high order effects. Recent years the important in the
development of numerical techniques has been the versatility of the method. In
this paper, we have present the various numerical techniques to compute such
effects in Microwave Integrated Circuit based designs, highlighting their
specific features with comparison of numerical techniques for design of
rectangular Microstrip Patch Antenna. Here we are compared few numerical
techniques, in this Finite Element Method is a more powerful and versatile,
more storage requirement, less CPU time. Numerical characterizations and
modelings of guided wave passive components have been an important research
topic in the recent years. This is due to increased research and development
in millimeter-wave integrated circuits and monolithic integrated circuits.
Another aspect important in the development of numerical techniques has been
the versatility of the method. Higher integration and smaller layout size, two
major trends in today’s RF/microwave industry, lead to more prominent
electromagnetic high order effects. In this paper, the authors present a
survey of existing Numerical techniques to compute such effects in microwave
integrated circuits, highlighting their specific advantages/disadvantages and
comparison for a circuit designers and simulation results also compared.
Keywords: Microwave Integrated Circuits, Numerical Techniques, Artificial Neural
Networks
Title
of the Paper: Study on MIMO Schemes for 3G-LTE Downlink
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Authors:
Guocai Li, Yaohuan Gong
Abstract: The combination of MIMO and OFDM becomes a key standardization work
for the downlink channel in 3G Long-Term Evolution (3G-LTE). This paper
studies one of the core techniques of 3G-LTE downlink: the coding and decoding
schemes in a time-variable multipath environment. It discusses the MIMO
schemes for 3G-LTE downlink, the STBC/SFBC, SFTC/STTC and Group layered SFC
coding-decoding schemes. This paper also discusses channel estimation scheme
based on pilot symbol assistance (PSA), including the pilot pattern and the
channel tracking algorithms. The computation complexity, frequency efficiency,
BER performance and the effects of channel estimation are analyzed under
multi-path fading channel environments. Then we give computer simulation
results for the coding-decoding schemes. We believe that results will provide
beneficial information to design the 3G-LTE downlink channels.
Keywords: 3G long-term Evolution(3G-LTE), MIMO-OFDM- STBC/SFBC, SFTC/STTC, Group
layered SFC
Title
of the Paper: A Burst Assembly Method to Reduce End-To-End Delay in Optical
Burst Switching Networks
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Authors:
Yukinobu Fukushima, Wenjie Chen, Yasuyuki Fujiwara, Tokumi Yokohira
Abstract: Although the offset-time-based scheme can differentiate loss rates
of packets according to their QoS levels in optical burst switching networks,
it also increases end-to-end delay of packets with higher QoS level. This is
because it increases offset time of bursts in proportional to QoS levels of
packets which are included in the bursts. In this paper, we propose a burst
assembly method that reduces end-to-end delay. Our proposed method includes
packets that arrive during the offset time into the currently assembled bursts
while the conventional method includes them into the burst assembled next
time. Simulation results show that our method offers 12–23% delay reduction
for packets with the highest QoS level.
Keywords: Optical Burst Switching (OBS), Offset-time-based scheme, end-to-end
delay, burst assembly method
Title
of the Paper: The Role of Branch-Correlation for an MC-CDMA System
Combining with Coherent Diversity over Frequency Selective Channels
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Authors:
Ta-Sheng Lan, Joy Iong-Zong Chen, Chieh Wen Liou, I. Mai Huang
Abstract: The diversity schemes include EGC (equal gain combining) and MRC
(maximal ratio combining) diversity combining with an MC-CDMA (multi-carrier
coded-division multiple-access) system operating in the cases of either
correlated or uncorrelated frequency selective fading channels are invested in
this paper. The sum of Nakagami-m variates (envelope intensity) is applied for
deriving the closed-form solution with arbitrarily correlated channels which
is for the purpose of avoiding the difficulty of explicitly calculating the
pdf (probability density function), for example, looking for the CF
(characteristic function), for the SNR (signal-to-noise ratio) at the output
of MRC or EGC scheme . Moreover, an alternative method utilized to obtain the
jpdf (joint pdf) with arbitrary correlation coefficient in terms of the
generalized Laguerre polynomial is adopted for the derivative. The analytical
results of the new derived BER (bit error rate) formulas are validated by an
example of the intensive Monte Carlo computer work in which consider a dual
correlated branch MC-CDMA system with several assumed system parameters. It
obviously shows that the well consideration and elimination the impact of
correlation between fading channels for MRC or EGC diversity scheme will
obtain the better system performance for an MC-CDMA system working in the
environment with frequency selective fading.
Keywords: Correlated frequency selective channels, EGC diversity, Nakagami-m
fading, MC-CDMA system, MRC diversity
Title
of the Paper: The Performance Analysis of an Multi-carrier System with
Correlated-and Uncorrelated-Nakagami-m Statistics
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Authors:
Joy Iong-Zong Chen, Kai-Chih Chuang, Ta-Sheng Lan
Abstract: In this letter the system performance of error rate probability
closed-form for an multi-carrier spread-spectrum, e. g., coded-division
multiple-access (MC-CDMA) system with linear diversity operating in frequency
selective fading channels are evaluated. The sum of correlated-Nakagami-m and
uncorrelated-Nakagami-m variates are adopted to derive the closed-form
solution with arbitrarily correlated channels which is for the purpose of
avoiding the difficulty of explicitly calculating the probability density
function (pdf), for instance, to search the characteristic functions (CF) of
the signal-to-noise ratio (SNR) at the MRC or EGC output. The analytical
results of the new derived bit error rate (BER) formulas are validated by an
example of the intensive Monte Carlo computer work in which consider a dual
correlated branch MC-CDMA system with some of assumed system parameters.
Keywords: Characteristic functions, frequency selective fading, MC-CDMA system,
linear diversity, correlated-Nakagami-m fading
Title
of the Paper: Design and Analysis of a Novel Dielectric Loaded Helical
Antenna
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Authors:
A. A. M Ezanuddin, P. J. Soh, A. A. H Azremi, R. B. Ahmad
Abstract: Helical antennas have been a popular antenna configuration for
various applications for its simple structure. This work describes the study
on a novel, custom-shaped dielectric loaded helical antenna incorporated on an
advanced material, which is Barium Strontium Titanate (BST). This material,
which presents the researcher with an advantage in size reduction due to its
high relative permittivity, is most suitably used when desiring a miniaturized
antenna compared to its conventional design of the same type. In the process
of designing, a parametric study was carried out by varying the antenna
geometrical parameters and the dielectric loading using the transient solver.
The detailed understanding of the sensitive parameters of the proposed antenna
will allow for ease of design reuse. Finally, an extended exploration was also
carried out in order to determine the design’s suitability for operation with
two of the WLAN Access Points (APs) already available in the market.
Observation from this investigation found out that the three most sensitive
parameters in the design are dielectric load’s height, radius of ground plane
and the helical height, with the dielectric load’s height as the main design
criteria. On the other hand, examination on the APs’ integration found out
that several factors influencing the radiation performance of the design are
the material used, internal spacing available and overall shape of the APs.
While both APs are proven to work with the designed antenna in the desired
frequency range, a degradation of up to 1 dB in gain have been observed, when
applying the antenna to the less suitable AP.
Keywords: Helical antenna, dielectric resonator, wireless local area network,
advanced material, Barium Strontium Titanate (BST)
Title
of the Paper: LMS Algorithm with an Adaptive Neural Network Cost Function
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Authors:
Jeng-Kuang Hwang, Yuan-Ping Li
Abstract: We propose a new LMS algorithm with an adaptive neural network cost
function (ANNCFLMS) for application to unknown channel estimation or system
identification. The algorithm employs the weighted average of a neural network
with two input signals—the squared errors at adjacent time intervals—to modify
the cost function and update the respective weight according to a gradient
descent algorithm designed to track the minimum mean squared error (MSE). For
fast convergence, the step-size updates recursively until the modified cost
function attains its minimum value. Simulation results demonstrate that the
proposed algorithm converges faster and is especially robust in low-SNR or
colored input environments.
Keywords: Adaptive filters, neural network, least mean square (LMS), variable
step-size, channel estimation
Title
of the Paper: An Efficient MIMO Detection Algorithm Employed in Imperfect
Noise Estimation
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Authors:
Chien-Hung Pan
Abstract: An efficient multiple-input multiple-output (MIMO) detection (MD)
algorithm includes novel, low-complexity, near-optimal and robust scheme is
proposed in wireless communications when imperfect noise estimation is
considered. By using MIMO technique, capacity increases proportionally as the
number of antennas is increased, but the introduced inter-antenna interference
(IAI) degrades system performance. To better mitigate IAI, we propose a
two-stage procedure to achieve maximum likelihood (ML) performance while
keeping at acceptable level of computational complexity. A novel two-stage
procedure is proposed as follows that is suitable for either in an
overdetermined or an underdetermined MIMO system. In an overdetermined system,
interference cancellation is first processed at Stage-1 using sorted QR
decomposition (SQRD) followed by Stage-2 that performs a genetic algorithm (GA).
In terms of computational complexity, this procedure provides three
significant advantages: 1) The SQRD scheme provides excellent interference
cancellation so as to largely improve initial setting of GA. 2) By using QRD,
fitness value evaluation of GA involves less complexity due to reducing the
matrix multiplication. 3) In aspect of diversity knowledge, lately decoded
sub-streams expect to have lower error probabilities by using SQRD. In this
paper, each mutated gene is decoded from the various diversity gains, termed
as a diversity mutation (DM) scheme. To achieve the fore-mentioned three
significant advantages in an underdetermined system, on the other hand, we
propose zero forcing (ZF) assisted SQRD GA-MD (ZF-SQRD GA-MD) to achieve ML
performance. Beside, the proposed two-stage detection procedure is quite
robust as it does not rely on noise information. Simulation results show that
the proposed two-stage detection procedure can achieve a near-ML performance,
but at a low-complexity level.
Keywords: Multiple-input multiple-output, inter-antenna interference, maximum
likelihood detector, sorted QR decomposition, genetic algorithm,
underdetermined
Title
of the Paper: Complexity Reduction by Using Triangular Matrix
Multiplication in Computing Capacity for an Optimal Transmission
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Authors:
Chien-Hung Pan
Abstract: Multiple-input-multiple-output (MIMO) technique is often employed to
increase capacity in comparing to systems with single antenna. However, the
computational complexity in evaluating channel capacity or transmission rate
(data rate) grows proportionally to the number of employed antennas at both
ends of the wireless link. Recently, the QR decomposition (QRD) based
detection schemes have emerged as a low-complexity solution. After conducting
QRD on a full channel matrix that results in a triangular matrix, we claim
that computational complexity can be simplified by the following ways. First,
to simplify channel capacity calculation, we prove that eigenvalues of the
full channel matrix multiplication equals eigenvalues of the triangular
channel matrix multiplication. Second, to simply evaluate optimal transmission
rate constrained constellation, we propose a simplified multiplication of the
resulted simple triangular matrix and a transmitted signal vector. Then, we
also propose a modified mutual information calculation (MMIC) to reduce the
multiplication complexity in combinational multiplication processes via the
divided calculation. This divided calculation is employed in the parallel
architecture for the field-programmable gate array (FPGA) implementation. That
is, the number of multiplications can be reduced via increasing the number of
additions in the FPGA implementation. By using the computer and FPGA
implementation, simulation results show that the proposed QRD-based schemes
are capable of achieving conventional performance, but at a low-complexity
level.
Keywords: Multiple-input multiple-output, channel capacity, QR decomposition,
eigenvalues, mutual information, field-programmable gate array
Title
of the Paper: An Improved Location-Aided Routing Protocol for Mobile Ad Hoc
Networks with Greedy Approach
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Authors:
Neng-Chung Wang, Yung-Fa Huang, Jong-Shin Chen, Si-Ming Wang, Chin-Ling
Chen
Abstract: A mobile ad hoc network (MANET) is a dynamically reconfigurable
wireless network that does not have a fixed infrastructure. Due to the high
mobility of nodes, the network topology of MANETs always changes. This makes
it more difficult to find the routes that message packets use when they are
routed. In this paper, we propose an efficient greedy location-aided routing (GLAR)
scheme to improve the efficiency of location-aided routing (LAR) scheme for
MANETs. In this scheme, we first decide a baseline, which is the line between
the source node and the destination node, for route discovery. The request
packet is broadcasted in a request zone based on the baseline to determine the
next broadcasting node. The neighboring node with the shortest distance to the
baseline is chosen as the next broadcasting node. We also propose a partial
reconstruction process that maintains a routing path. When a node on a routing
path finds that a link is broken, the node starts the process of routing
maintenance. Simulation results show that the proposed GLAR can reduce the
control overhead and increase the route lifetime than LAR.
Keywords: Expected zone, Global positioning system, Location-aided routing,
Mobile ad hoc networks, Request zone
Issue 9, Volume 8,
September 2009
Title
of the Paper: Energy-Aware Secure Routing for Large Wireless Sensor
Networks
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Authors:
Theodore Zahariadis, Helen C. Leligou, Stamatis Voliotis, Sotiris Maniatis,
Panagiotis Trakadas, Panagiotis Karkazis
Abstract: Wireless Sensor Networks (WSN) are vulnerable to a wide set of
attacks which threaten the network operation. Although communication and
security technologies for computer networks have reached a mature stage, their
applicability in WSNs is disputable due to their infrastructure-less operation
and the limited node and network resources. Focusing on the routing procedure,
this relies in the cooperation among neighboring nodes and a long list of
attacks that can cause serious damage have already been identified. The
situation is futher aggravated as the next generation wireless sensor network
will be larger and larger. To face this problem, we propose a secure routing
protocol (Ambient Trust Sensor Routing, ATSR) which adopts the geographical
routing principle to cope with the network dimensions and part of the routing
attacks, while it relies on a distributed trust model for the detection of
another part of the routing attacks. Both direct and indirect trust
information is taken into account to evaluate the trustworthiness of each
neighbour. An important feature of the proposed routing solution is that it
takes into account the remaining energy of each neighbour, thus allowing for
better load balancing and network lifetime extension. Based on computer
simulation results we evaluate the additional energy consumption caused by the
exchange of indirect trust information and the benefits stemming from the
adoption of our algorithm.
Keywords: Wireless Sensor Networks, routing, security, trust model, energy
awareness
Title
of the Paper: The Performance of Macrodiversity System in the Presence of
Long-Term and Short-Term Fading
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Authors:
Caslav Stefanovic, Dragana Krstic, Ana Pesic, Mihajlo Stefanovic, Dejan
Petkovic
Abstract: Probability density function (PDF), moments of signal and amount of
fading (AF) at the output of macrodiversity system in closed form are
obtained. Moreover, level crossing rate (LCR) of signal at output of macro
diversity system is analytically derived and used to study average fade
duration (AFD) of the proposed system. Dual maximal-ratio combining (MRC) is
implemented at the micro level (single base station) and selection combining
(SC) with two base stations (dual diversity) is implemented at the macro
level. This model assumes a Nakagami-m density function for the envelope of
the received signal and a gamma distribution to model the average power to
account for the shadowing. The results are shown graphically for different
signal and fading parameters values.
Keywords: Shadowing, Nakagami-m Fading, Microdiversity, Macrodiversity,
Probability Density Function, Amount of Fading
Title
of the Paper: Analyze of the MPEG-4 Compressed Streams
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Authors:
Iulian Udroiu, Ioan Tache, Corneliu Salisteanu, Ion Caciula
Abstract: In this paper, an analysis of video quality of compressed MPEG-4
stream is performed. The video quality is performed using a test system
composed by two metering devices: TEKTRONIX PQA500 Picture Quality Analyzer
and TEKTRONIX MTS4EA Elementary Stream Analyzer. The measured parameters of
compressed MPEG-4 signal are: macro block measurements and PSNR.
Keywords: Video quality signal, macro block measurements, MPEG-4, PSNR, DMOS
Title
of the Paper: QoS Management in Experimental Environment
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Authors:
Drago Zagar, Goran Martinovic, Slavko Rupcic
Abstract: New applications usually combine interactivity and multimedia
resulting in a huge diversity of possible services. The negotiated quality of
service should be result of application/user requirements and network
possibilities. The most important topic in QoS provision is how to efficiently
manage network resources. This paper describes an experimental implementation
of the QoS network management for serving the users by some defined QoS
characteristics. The applications developed for negotiation and maintenance of
the desired quality of service between the server and clients are analyzed.
The main classes of developed applications as well as the connections between
applications/ objects are described. Finally, some results describing
functionality of QoS management in experimental environment are shown.
Keywords: Quality of Service, negotiation, network resources, IP networks, QoS
Management, QoS Parameters
Title
of the Paper: An Image Encryption using Pseudo Random Bit Generator based
on a Non-Linear Dynamic Chaotic System
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Authors:
Algimantas Citavicius, Audrius Jonavicius
Abstract: This paper deals with the image encryption scheme based on
non-linear dynamic chaotic system in stream cipher architecture. The narrowing
of the numbers domain interval to [0.2, 0.8] and a double precision floating
point format to encode float numbers to binary format were used for pseudo
random stream generator. The results of the NIST statistical test suite and
security analysis are given. The results show very good cryptographic
properties and high security.
Keywords: Image encryption, Non-linear chaotic dynamic system, Stream generator,
Security analysis, Cryptography
Title
of the Paper: Analysis and Design of Applicator System for Regional
Induction Heating 2.45 GHz
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Authors:
Chumpon Patummakasorn, Chanchai Thongsopa
Abstract: In this paper, the design of applicator system for regional
induction heating at 2.45 GHz and using noninvasive method. The distribution
of the lossy medium was analyzed using the finite difference time domain
method(FDTD). The objective is to determine the area which the heat is
uniformly distributed. The result from this paper was believed to be
effectively when it was applied to the cancer treatment. The applicator
utilized was the inducting spiral coils which were sets of two coils and four
coils, and each coil has its own power-supply unit. It was fabricated by using
magnetron sources operating at frequency of 2.45 GHz. The energy supplied to
the induction coil was timely controlled. The results from the simulation and
experimental of heating area from lossy medium were compared. Both simulation
and experimental results showed good no conflict. The activation of supply
units one at a time generated more heating wide area than the one when all
units were activated at the same time. The results showed that the applicator
with four coils generates more heating wide area than the one with two coils.
Another interesting point is that the activation each power supply unit was
turned on one by one generates more heating wide area than the activation all
power supply units were turned on. In this study, both two coils and four
coils were capable of producing a temperature rise of 7 Celsius degrees for 10
min. Moreover, the results from this investigation can be applied to various
designs of heating wide area applicator and another advantage is its cost
effectiveness.
Keywords: Applicator, Hyperthermia, Induction heating, lossy medium, finite
difference time domain, agar phantom
Title
of the Paper: Analytical Description of a Parameter-based Optimization of
the Quality of Service for VoIP Communications
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Authors:
Leopoldo Estrada, Deni Torres, Homero Toral
Abstract: In this work, the perceived quality of VoIP communications is
studied. The distributions of the number of consecutive received and lost
packets, respectively named gap and burst, of a VoIP communication are modeled
with discrete two-state and four-state Markov chains. Algorithms for
estimating the transition probabilities between states and from these, the
packet loss rate and the respective gap and burst length distributions, are
described. Through a study of monitored VoIP calls, it is shown that these
models can adequately represent the geometric-type decay of these
distributions and that although two-state model performs well for homogeneous
losses, for non-homogeneous losses the four-state model fits better. An
analysis of the performance of a packet-level FEC scheme, based on ??-packet
redundancy, is presented. The perceived packet loss rate that results of
applying this correction scheme is quantified. For the studied measurements,
1-packet redundancy is sufficient to decrease the perceived loss rate below
1%. Also, the impairments of the perceived quality of voice after the FEC
technique and a de-jitter buffer is quantified. The resulting equations can be
used to optimize the adjust parameters of the VoIP call, e.g., level of
redundancy, type of codec used and de-jitter buffer size. The proposed
methodology can be extended if other types of improvements are included.
Keywords: VoIP, Packet loss distribution, Packet reception distribution, ??-packet
FEC, QoS
Issue 10, Volume 8,
October 2009
Title
of the Paper: Simulation and Modeling of Packet Loss on VoIP Traffic: A
Power-Law Model
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Authors:
Homero Toral, Deni Torres, Leopoldo Estrada
Abstract: In this paper, through an extensive analysis it is shown that VoIP
traffic jitter exhibits self-similar and heavy-tail characteristics. From this
analysis, we observed that α-stable distribution particularly gives the best
goodness of fit; this fact has implications on the design of de-jitter buffer
size. On the other hand, we investigate the packet loss effects on the VoIP
jitter, and present a methodology for simulating packet loss on VoIP jitter
traces. In order to represent the packet loss process, the two state Markov
model or Gilbert model is used. We proposed two new models for VoIP traffic;
these models are based on voice traffic measurements, and allow relating the
Hurst parameter and α parameter with the packet loss rate. We found that the
relationship between these parameters and packet loss rate obeys a power-law
function with three fitted parameters.
Keywords: VoIP, QoS, Packet Loss Rate, Jitter, Heavy-Tail Distributions, Self-Similar,
α Parameter, Hurst Parameter, De-Jitter Buffer, Two-State Markov Model
Title
of the Paper: A Diachronic Study of POP Album Cover from 1980 to 1992 in
Taiwan
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Authors:
Manlai You, Li-Min Chen
Abstract: Based on the color attributes of pop album cover, a diachronic study
was conducted. It was argued that the denotation is significant related to the
color attributes and the connotation is not necessary significant related to
the color attributes. The population of this study was those pop albums
published from 1980 to 1989. In those years, this country was gradual opening
up of political and economic stability. The sampled representative pop album
covers were collected and put on the computer screen for conducting content
analysis. The denotation and color attributes of each sampled album cover were
also identified for statistical test. A logit regression was used to predict
denotation of pop album cover from mean value of color channel Red, Green, and
Black. The C5.0 model was used to build a rule set and a decision tree for
further illustrate the relation between color attribute and denotation.
Keywords: POP album cover, diachronic study, color attribute, denotation
Title
of the Paper: An Efficient Direct Anonymous Attestation Scheme with Forward
Security
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Authors:
Deng-Guo Feng, Jing Xu, Xiao-Feng Chen
Abstract: Direct Anonymous Attestation (DAA) is a cryptographic mechanism
adopted by the Trusted Computing Group in its specifications for trusted
computing platforms (TCP). In this paper, we propose a new DAA scheme and
prove it is secure under the strong RSA assumption and the decisional
Diffie-Hellman assumption. While satisfying all the security properties
proposed in previous DAA schemes, our scheme provides a new desired security
property, forward security: compromise of the current private key of TPM does
not enable an adversary to forge signatures pertaining to the past. Such
forward security is important to mitigate the damage caused by private key
exposure.
Keywords: Trusted computing platform, Direct anonymous attestation, Forward
security, Trusted platform module
Title
of the Paper: M-MENTOR: A Design Algorithm for IP Networks with Mixed
Traffic
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Authors:
Annop Monsakul, Pisit Charnkeitkong
Abstract: The design of IP networks to support traffic engineering for both
unicast and multicast traffic is a very difficult problem. This paper proposes
a heuristic design algorithm called M-MENTOR that concern routing of both
types of traffic. However, since multicast traffic model could be employed in
many situations and could be managed by various kinds of multicast routing
protocols, this paper consider only the design process of the IP networks with
following features: (1) network of within the same Autonomous System (AS), (2)
routing protocol support multiple weight on each link, (3) the multicast
traffic from different sources share the same multicast tree. The efficiency
of M-MENTOR is evaluated for various traffic demands and networks of 10, 30
and 50 node and compared with MENTOR-II. The experimental results show that,
in almost all cases, M-MENTOR give better performance in term of installation
cost.
Keywords: IP Network Design, MENTOR Algorithm, Unicast/Multicast Traffic,
Traffic Engineering
Title
of the Paper: Performance Evaluation Model of Optimization Methods for
Wireless Sensor Networks
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Authors:
Goran Martinovic, Josip Balen, Drago Zagar
Abstract: Wireless sensor networks are often composed of large number of
wireless sensor nodes that are mostly using battery supplies. Nodes are small
and equipped with sensors that cooperatively monitor physical world.
Communication, sensing and computing have the most influence on performance
and power consumption of wireless sensor networks. Various optimization
methods are used to decrease power consumption and improve performance of
wireless sensor networks. One of the novel methods is cross-layer approach. In
this paper, first we present the advantages of cross-layer approach. The
articles that are using a cross-layer approach for improving performance and
energy preservation in wireless sensor networks are reviewed and state of the
art is presented. In their work, scientists propose various optimization
methods that are improving performance and decreasing power consumption. One
of the fundamental problems is how to systematically make the performance
evaluation and get the real contribution of these proposed optimization
methods. In this paper, we develop benchmark methodology and performance
evaluation model of various optimization methods for wireless sensor networks.
Furthermore, we present the benchmark application for collecting and comparing
performance measurement results of various optimization methods.
Keywords: Benchmark Application, Benchmark Methodology, Cross-Layer, Metrics,
Performance Evaluation Model, Wireless Sensor Networks
Title
of the Paper: Efficient Key Management Scheme for Hierarchical Access
Control in Mobile Agents
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Authors:
Hsing-Bai Chena, Chun-Wei Liaob, Chang-Kuo Yehc
Abstract: Mobile agents have great potential for increasing the realized
benefit for a variety of e-commerce applications. However, enabling the mobile
agent to safely travel over the open and uncontrollable Internet is necessary
to protect the contents of a mobile agent. Recently, many agent structures
that manage the keys needed to provide the access control mechanism for mobile
agents have been developed. Nevertheless, these structures require either
large amount of mobile codes or heavy computation loads. In this paper, a
lightweight key management method for hierarchical access control in mobile
agent environments is proposed. This method not only provides access control
for mobile agents but also reduces the agent size as well as cuts down the
computations cost.
Keywords: Access control, Information security, Key management, Mobile agent
Title
of the Paper: Modern Communications used New Formulation to the Proporation
of Laplace Transforms
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Authors:
Igried Dib Al-Khawaldeh
Abstract: Laplace transforms was introduced long time ago, it had explained
better afterward, and had many Engineering applications like (control,
signals, circuits, etc.), unfortunately it still has a lot of ambiguity and is
difficult to be understood by the beginners. In this paper the transformation
laws are re-formulated in a brief and unforgettable form, and then a
conclusion has been reached for the first time that the transformation laws
are symmetric.
Keywords: Congestion Control, Signals, Transformation
Issue 11, Volume 8,
November 2009
Title
of the Paper: High Range Resolution Synthesized by Non-linear
Stepped-Frequency Chirp Pulse Train
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Authors:
Yingrui Hu, Xuegang Wang
Abstract: Traditional stepped frequency chirp pulse train methods suffer from
high sidelobes and ambiguous peaks, known as grating lobes and difficulty in
compensating Doppler effect caused by target motion. This paper investigates a
class of non-linear stepped frequency chirp pulse train with low sidelobes and
capability to cancel clutter and to compensate motion. We present analytic
expression for its autocorrelation function (ACF) and propose an improved
method to produce the non-linear stepped frequency chirp pulse train with
small grating lobes and small overlap ratio for sub-pulse of large time
bandwidth product. A method for estimation a target’s radial velocity is
developed, which avoids multiple bursts required by other methods. The high
signal-to-noise (SNR) ratio as a result of sub-pulse compression assures the
accuracy of estimation. The Cramer-Rao bound for lower limit on the velocity
estimation of the pulse train is derived to demonstrate its performance.
Keywords: Non-linear stepped-frequency chirp pulse train, Autocorrelation
function, Grating lobes suppression, Motion compensation, Cramer-Rao bound,
One-dimensional range profile
Title
of the Paper: An Efficient Zone-Based Multicast Routing Protocol for Ad Hoc
Network
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Authors:
Tain-Sao Chang, Jyh-Horng Wen, Tzu-Ting Wu
Abstract: This study presents a forwarding nodes selection scheme for
zone-based multicast routing protocols to reduce transmission routing control
overhead. The feasibility of the proposed scheme is demonstrated over mobile
ad hoc networks (MANETs), and compared with the multicast zone routing
protocol (MZR) in terms of the routing control overhead and packet delivery
ratio. In this work, the proposed scheme represents a good reduction of
forwarding packets. Furthermore, simulation results show that the proposed
scheme presents effective forwarding nodes selection for reduction routing
control overhead and increasing packet delivery ratio.
Keywords: Forwarding node selection, multicast routing, mobile ad hoc network,
multicast zone routing protocol, routing control overhead, packet delivery
ratio
Title
of the Paper: Certificateless Authenticated Group Key Agreement Protocol
for Unbalanced Wireless Mobile Networks
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Authors:
Chung-Fu Lu, Tzong-Chen Wu, Chien-Lung Hsu
Abstract: In 2004, Bresson et al. proposed a mutual authentication and group
key agreement protocol for unbalanced wireless networks. Tseng recently
proposed a novel secure protocol to improve Bresson et al.’s protocol.
However, both protocols are based on certificate-based public key systems and
insecure against the so-called impersonation attacks. They might be unsuitable
for unbalanced wireless mobile networks from the viewpoints of security,
computational complexities, and communication overheads. This paper proposes a
certificateless authenticated group key agreement (cAGKA) protocol based on
elliptic curve discrete logarithms. The proposed cAGKA protocol is more secure
and efficient than previously proposed protocols for unbalanced wireless
mobile networks due to the following facts: (i) The entity authentication and
the authenticity of the intended public keys can be simultaneously verified in
a logically single step without requiring any public key certificates. (ii)
Bit sizes of the keys and the related messages are relatively smaller than
those of the previously proposed protocols for the same security level. (iii)
It saves the required communication overheads, and computational complexities.
(iv) It achieves mutual authentication, impersonation attack resistance,
explicit key confirmation, forward secrecy, contributory key agreement, and
group key updating.
Keywords: Group key agreement, Certificateless, Elliptic curve, Unbalanced
wireless networks, implicitly-certified
Title
of the Paper: QPPS : Qos Provision Packet Scheduling Algorithm in High
Speed Downlink Packet Access
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Authors:
Ying-Hong Wang, Kuo-Feng Huang
Abstract: The 3rd Generation WCDMA standard has been enhanced to offer
significantly increased performance for packet data. But coming application
such as multimedia on desiring data rates will urge the UMTS support. To
support such high data rates, High Speed Downlink Packet Access (HSDPA)
labeled as 3.5G wireless system, has been published in UMTS Release 5. Under
the HSDPA system, it will have to support high speed transmission and promises
a peak data rate of up to 10Mb/s. To achieve such high speed rate, system
provides the information of Channel Quality Indicator (CQI) information to
detect the air interface condition. Then, there are many channel condition
related scheduling schemes have been proposed to attend achievement of high
system performance and guarantee the quality-of-service (QoS) requirements.
However, there is no solution of packet scheduling algorithm can consider
differences of data-types priority management under the hybrid automatic
repeat (HARQ) scenario. In this paper, we propose the weight combination
packet scheduling algorithm to target to enhance the system efficiency and
balance QoS requirements. The proposed schemes is simulated with OPNET
simulator and compared with the Max CIR and PF algorithms in fast fading
channel. Simulation result shows that the proposed algorithm can both increase
the cell throughput effectively and meet user’s satisfaction base on QoS
requirements.
Keywords: HSDPA, UMTS, Scheduling, QOS
Title
of the Paper: An Interference Suppression Scheme for MIMO-OSTBC System
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Authors:
Jie Wang, Zhonghao Zhang, Yuehuan Gong, Tao Liu
Abstract: Multiple Input Multiple Output (MIMO) technique is considered as a
cost-effective and promising technique for the next generation wireless
system. Orthogonal Space-Time Block Codes (OSTBC) scheme is one of the most
important coding schemes for MIMO system. The performance of an MIMO system
using OSTBC (MIMO-OSTBC), however, degrades significantly in presence of
strong interferences. In this paper, an interference suppression scheme for
MIMO-OSTBC system in strong interference scenario is presented. The proposed
scheme is based on simplified Maximum Likelihood (ML) decoding and noise
subspace projection. The scheme has the following advantages: realizing ML
decoding of the OSTBC and greatly reducing searching calculations by simple
linear processing; avoiding matrix-inversion computation needed in ordinary
suppression schemes through noise subspace projection. The paper also
discusses the method of obtaining the efficient channel state information
(CSI) needed in the proposed scheme in strong interference scenario.
Simulation results are given to verify the interference suppression ability of
the proposed scheme and our theoretical analysis. Compared with other
suppression scheme, the proposed scheme has better SER performance and is more
flexible in practical applications.
Keywords: MIMO, OSTBC, ML Decoding, Interference Suppression, Noise Subspace
Projection
Issue 12, Volume 8,
December 2009
Title
of the Paper:
Network Coding: An Excellent Approach for Overloaded Communication Era
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Authors:
Marium Jalal Chaudhry, Farhat Saleemi, Fatima Jalal Chaudhry
Abstract: Data flow in graphs is one of the most principle challenges faced by
computer scientists and mathematicians. The problem of data flow in a graph
has many practical applications e.g. routing in internet and wireless
networks, where major purpose is to provide quality of service guarantees
improved throughput, delay reduction etc. we will be using novel technique of
network coding to device strategy to achieve theoretically maximum possible
data flow in a network. Network is a new paradigm which in contrast to
traditional routing allows mixing of data elements. This paper will present
the developed algorithms of network coding, their performance analysis,
simulation results and gains in terms of quality of service. Our results will
particularly focus on improving throughput and reducing number of
retransmissions, better network management by using network coding approach,
we also show our experimental setup and experimental results which naturally
graph up the network coding in this overloaded era.
Keywords: Wired Network Coding, Routing, Gain
Title
of the Paper:
Performance of Blind Successive Interference Canceller for Multi-Carrier CDMA
Systems
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Authors:
P. A. Haris, E. Gopinathan, C. K. Ali
Abstract: An efficient multiple user access over the wireless channel
necessitates a communication system design that can overcome the adverse
impact of multipath propagation such as Inter Symbol Interference (ISI) and
Multiple Access Interference (MAI). This being the objective, a Multi Carrier
Code Division Multiple Access (MC-CDMA) communication system is considered in
this paper. MC-CDMA, being a combination of DS-CDMA and OFDM converts a
frequency selective fading channel into multiple flat fading channels thereby
mitigating ISI. To overcome the effect of MAI, Multi User Detection (MUD)
based receiver is addressed. The performances of Blind successive Interference
Cancellation (BIC) techniques are compared with Matched filter receiver and
BMMSE receiver by simulating the entire system. The BIC is a multi-user
detection technique that uses knowledge of only the desired user's signature
sequence and his timing to estimate his information. This is done by executing
interference cancellation in a successive manner, starting from the most
dominant component and successively canceling the weaker ones. Simulation
results show that BIC scheme outperforms conventional MF receiver and BMMSE
receiver.
Keywords: Inter symbol interference, Multiple Access interference, Multi user
detection, Single user lower bound, Maximum mean energy
Title
of the Paper:
The Effect of an Enhanced Channel Assignment Algorithm on an IEEE 802.11 WLAN
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Authors:
Mohamad Haidar, Hussain Al-Rizzo, Robert Akl, Zouhair El-Bazzal
Abstract: In this paper, a channel-assignment algorithm at the Access Points (APs)
of a Wireless Local Area Network (WLAN) is proposed in order to maximize
Signal-to-Interference Ratio (SIR) at the user level. We start with an initial
channel assignment based on minimizing the total interference between APs.
Based on this assignment, we calculate the SIR for each user. Then, another
channel assignment is performed based on maximizing the SIR at the users. The
algorithm can be applied to any WLAN, irrespective of the users’ and load
distributions. Simulation results showed that the proposed algorithm is
capable of significantly increasing the SIR over the WLAN, which in turn
improves throughput. Finally, several scenarios were constructed using OPNET
simulation tool to validate our results.
Keywords: Signal-to-Interference Ratio, WLAN, Channel Assignment, Access Points,
OPNET
Title
of the Paper:
Tag Anti-Collision Algorithms in RFID Systems - A New Trend
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Authors:
Majid Alotaibi, Adam Postula, Marius Portmann
Abstract: RFID is a wireless communication technology that provides automatic
identification or tracking and data collection from any tagged object. Due to
the shared communication channel between the reader and the tags during the
identification process in RFID systems, many tags may communicate with the
reader at the same time, which causes collisions. The problem of tag collision
has to be addressed to have fast multiple tag identification process. There
are two main approaches to the tag collision problem: ALOHA based algorithms
and tree based algorithms. Although these methods reduce the collision and
solve the problem to some extent, they are not fast and efficient enough in
real applications. A new trend emerged recently which takes the advantages of
both ALOHA and tree based approaches. This paper describes the process and
performance of the tag anti-collision algorithms of the tree-ALOHA trend.
Keywords: RFID, Collision, Frame, Algorithm, Aloha, Tree, Tag
Title
of the Paper:
Characterization of Advanced Round Robin Scheduler
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Authors:
Tamas Marosits, Sandor Molnar
Abstract: In this paper we show that Advanced Round Robin (ARR) scheduler is
in the class of Latency Rate servers and it also belongs to the class of
Guaranteed Rate servers. We present the latency parameter and the error term
of ARR. Next, we evaluate the fairness characteristic. Finally, we describe
the relationship between ARR and Generalized Processor Sharing. All of these
results can make the comparison of ARR easily to other known schedulers and
help designers to apply ARR.
Keywords: Round Robin scheduling, Latency Rate servers, GPS, fairness
Title
of the Paper:
Software Defined Adaptive Codec for Cognitive Radio
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Authors:
Rajeshree D. Raut, Kishore D. Kulat
Abstract: Recently, Cognitive Radio has been proposed as a promising
technology to improve spectrum utilization. A highly flexible SDR (Software
defined Radio) system needs to configure each of its blocks to give optimum
performance over the available bandwidth. Present work discusses an approach
for software defined adaptive coder yielding minimum BER (Bit error rate) for
emergency services over cognitive radio. The results verify the efficiency of
the algorithm which configures the convolution encoder to produce a lower BER
for increased Bandwidth available. This can be readily implemented in the SDR
library functions. This has been tested by FPGA implementation of the
convolution encoder using Matlab HDL coder. The coder output of the FPGA
implemented VHDL code has also been presented. Various WiMax Systems to be
included in the SDR Library are puttforth. SDR adapts to the best suitable
design, yielding lower BER in available channel conditions.
Keywords: Cognitive Radio, SDR library, Rate Adaptive Coder, BER, FPGA
implementation
Title
of the Paper:
Performance Measurement and Queueing Analysis at Medium-High Blocking
Probability of Parallel Connection Servers with Identical Service Rates
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Authors:
Chung-Ping Chen, Ying-Wen Bai
Abstract: In this paper we propose a performance measurement and queueing
analysis for medium-high blocking probability where the service rate is less
than equal to the arrival rate of parallel connection servers, and for which
we can estimate the system response time. First, we calculate the system
response time of the parallel network. Second, we simulate the queueing model
of the parallel network and calculate the system response time. Third, we
measure the system response time by using different numbers of ASP
multiplication loops to represent the different service rates of the parallel
network. Fourth, we take 30,000 data for imitation as the foundation and use
linear regression to compare the measurements of both the system response time
and the search service rates of the actual system under different service load
conditions. Fifth, we compare the system response time of a single server with
up to ten parallel connection servers and compute the discrepancy in their
efficiency.
Keywords: Parallel Network, Web Servers, Service Rate, Parallel Connection
Servers, Queueing Anallysis
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