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Issue 1, Volume 10,
January 2011
Title of the Paper: New General
Transformations for 2-D FIR and IIR Filters’ Design
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Authors: Nikos E.
Mastorakis
Abstract: In this paper, new general transformations for designing 2-D
(Two-Dimensional) FIR and IIR filters are provided. The present methodology
can be viewed as an extension of the McClellan Transformations and can be
applied in several cases of 2-D FIR and IIR filter design. Numerical examples
illustrate the validity and the efficiency of the method.
Keywords: 2-D Filters, FIR
Filters, IIR Filters, Multidimensional Systems, Multidimensional Filters,
Filter Design, McClellan Transformations
Title of the Paper: Transformations for
Direct Design of 2-D Filters from Appropriate 1-D Functions
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Authors: Nikos E.
Mastorakis
Abstract: In this paper, general transformations for designing 2-D
(Two-Dimensional) IIR filters are provided. The present approach can be viewed
as an extension of the classical method of magnitude approximation and can be
applied in several cases of 2-D filter design. Numerical examples illustrate
the validity and the efficiency of the method.
Keywords: 2-D Filters, FIR
Filters, IIR Filters, Multidimensional Systems, Multidimensional Filters,
Filter Design, McClellan Transformations
Title of the Paper: Nonlinear
Integrator Backstepping for Traffic Flow Speed Control of Automated Freeway
System
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Authors: Xu-Hua Yang,
Sheng-Yong Chen, Wan-Liang Wang
Abstract: In an automated freeway system environment, computers replace
artificial driving and control vehicles accompany movement, which can greatly
reduce randomness. In this paper, we propose a traffic flow speed controller
with lower complexity which can send speed commands to regulate the speeds of
vehicles in each section of a freeway. On the basis of the theory of nonlinear
integrator backstepping, the controller can guarantee exponential convergence
of the traffic flow speed at each section to the desired speed. Compared with
former method, the establishment of this controller need not solve inverse
matrix, and therefore, reduces algorithm’s complexity, improves the algorithm
efficiency and automatically satisfies the controllability condition.
Simulations show that this controller can effectively reduce congestion and
helps to achieve a smooth traffic flow on a congested freeway.
Keywords: Speed
controller, automated freeway system, traffic control, nonlinear integrator
backstepping, traffic flow model, exponential convergence
Title of the Paper: An Evaluation for
the design of Asynchronous Systems
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Authors: Sun-Yen Tan,
Wen-Tzeng Huang
Abstract: The asynchronous circuit style is based on micropipelines, a style
used to develop asynchronous microprocessors at Manchester University. This
paper has presented some engineering work on developing a technique of sharing
resources for micropipeline circuits. The work presented in this paper shows a
comparison of 2-phase and 4-phase implementations in transistor count, speed,
and energy. Though the nature of the work is mainly engineering, there are
some significant new insights gained in the course of the work. In resource
sharing the 2-phase implementations have better performance than the
four-phase implementations. There is no “return to zero” problem. Fork and
join cost nothing to the two-phase implementations. With some additional
buffer stages the 4-phase implementations using the fully decoupled and long
hold latch control circuits can also implement resource sharing. However, the
four-phase implementations using the simple and semi-decoupled latch control
circuits require more buffer stages to avoid deadlock.
Keywords: Asynchronous
design, Micropipelines, Processor, Sharing resources, Synthesis
Issue 2, Volume 10,
February 2011
Title of the Paper: Design,
Implementation and Evaluation of an Optimal Iterative Learning Control
Algorithm
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Authors: V. Vita, A.
Vitas, G. E. Chatzarakis
Abstract: Iterative learning control (ILC) is used to control systems that
operate in a repetitive mode, improving tracking accuracy of the control by
transferring data from one repetition of a task, to the next. In this paper an
optimal iterative learning algorithm for discrete linear systems is designed
and implemented. The design and implementation that have been done using
Matlab® 7 and Simulink are described in detail. The algorithm is applied on
several representative discrete systems cases in order to be evaluated and to
reveal its capabilities and limitations.
Keywords:
Discrete linear systems; iterative learning control; Matlab® 7; simulation
Title of the Paper: Application of
Neural Networks for Control of Inverted Pendulum
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Authors: Valeri Mladenov
Abstract: The balancing of an inverted pendulum by moving a cart along a
horizontal track is a classic problem in the area of automatic control. In
this paper two Neural Network controllers to swing a pendulum attached to a
cart from an initial downwards position to an upright position and maintain
that state are described. Both controllers are able to learn the demonstrated
behavior which was swinging up and balancing the inverted pendulum in the
upright position starting from different initial angles.
Keywords:
Neural networks, inverted pendulum, nonlinear control, neural network
controller
Title of the Paper: Identification of
Impending Interturn Faults in Random Wound Induction Motors Used in Adjustable
Speed Drives
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Authors: S. Ponnuswamy
Rajkumar, J. Sudesh Johny, A. Ebenezer Jeyakumar
Abstract: Diagnosis of stator current has been presented by several authors
for identifying various bearing and rotor faults in an induction motor.
However, there is very limited literature covering the effect of interturn
faults on the stator current pattern. This is due to the reason that the
effect of motor interturn insulation faults in the initial stages being not
discernable and any changes in the capacitive current components are
negligibly very small and of very high frequency content. This paper deals
with a simple technique, utilizing the effect of the interturn fault in
modifying the high frequency components of the applied pulse width modulated
(PWM) voltage. Insulation Resistance (IR) and Polarization Index (PI) are two
universally accepted diagnostic tests for insulation tests. The change in
insulation strength between the turns affects the capacitive component of the
stator line current. Resulting changes in wave shapes of applied voltage have
been studied with respect to both the distance of interturn faults from line
end and reduction in the insulation strength; and hence in the insulation
resistance value. The studies have been made by computer simulation and
validated by experiments. There is ample evidence that an impending and
progressing interturn fault can be identified in Adjustable Speed Drives
driven by frequency converters by studying line end coil voltage waveforms.
Keywords:
Repetitive switching surges, Stator line current, PWM Voltage, Adjustable
speed drives, Motor insulation, Interturn faults, High-frequency capacitive
current components
Title of the Paper:
Unbalanced-Grid-Fault Ride-Through Control for a Doubly Fed Induction
Generator Wind Turbine with Series Grid-Side Converter
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Authors: Yong Liao, Hui
Li, Jun Yao
Abstract: The grid codes now require doubly fed induction generator (DFIG)
wind turbines having the “low voltage ride-through (LVRT)” capability.
However, a traditional DFIG with a partially rated back-to-back converter has
inherent difficulties to ride through the grid faults, especially for the
unbalanced grid faults. Modifications to the traditional DFIG configuration
for ride-through have become necessary. A DFIG system with series grid-side
converter (SGSC) has an excellent potential for voltage dips tolerance. This
paper analyzes the reasons of a DFIG system with SGSC for ride-through and
presents a control scheme for operation under unbalanced grid faults
conditions. During grid faults, the each component of the generator’s stator
flux is effectively controlled through the SGSC. Also, the stator and rotor
currents are further restricted by controlling the rotor-side converter (RSC)
to reduce the absorbing energy from wind turbine. Then, successful
ride-through of a DFIG system with SGSC under all types of severe unbalanced
grid faults at the point of common coupling (PCC) are achieved with reduced
electromagnetic torque oscillation. The proposed control scheme is validated
by means of simulations.
Keywords:
Doubly fed induction generator (DFIG), series grid-side Converter (SGSC),
unbalanced grid fault, wind turbine, low voltage ride-through (LVRT), wind
power generation, voltage dips, voltage sags
Issue 3, Volume 10,
March 2011
Title of the Paper: An Analyze on a
Wood Processing Automatic Machine
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Authors: Gabriel Nicolae
Popa, Corina Maria Dinis, Sorin Ioan Deaconu, Angela Iagar
Abstract: In this work is presenting an automatic machine used in the wood
processing industry. These machines have the advantage of flexibility in
achieving of some diverse finished products, by using the same processing
tools, the single modification being made on the machine’s program. As
accurate drive elements are also used stepping motors that can be supplied and
controlled in different modes. Hereby is presenting a unipolar control mode of
a 4-coil stepping motor controlled by 4 transistors with field effect. For
this circuit, there is the possibility of its control by the development mode
with microcontroller or PC.
Keywords:
Automatic machine, control, stepping motor, unipolar
Title of the Paper: Interleaved
Soft-Switching Buck Converter with Coupled Inductors
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Authors: Cheng-Tao Tsai,
Chih-Lung Shen
Abstract: This paper presents an interleaved soft-switching buck converter
with coupled inductors to extend duty ratio for high step-down voltage
applications. In the proposed converter, a single-capacitor turn-off snubber
is introduced to limit voltage rising rate of active switches to reduce
turn-off loss. To handle the energy trapped in the leakage inductance of the
coupled inductors, simple passive-clamp circuits are added to the proposed
converter, which can effectively recycle the energy and suppress voltage
spike. To highlight the merits of the proposed converter, its performance
indexes, such as voltage gain function and component stresses, are analyzed
and compared with those of the conventional interleaved buck converter. In
this study, a prototype of the proposed converter, of which input voltage
range is 127-177 Vdc, output voltage is 12 Vdc, and power capacity rates at
240 W, has been designed and implemented to verify the feasibility. From
experimental results, it has been shown that conversion efficiency up to 85%
can be achieved at full load condition.
Keywords:
Interleaved, soft-switching, coupled inductors, leakage inductance,
passive-clamp circuits
Title of the Paper: A Transfer Method
of Public Transport Network Based on Adjacency Matrix Multiplication Searching
Algorithm
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Authors: Bo Wang, Xu-Hua
Yang
Abstract: In this paper, we model the public transport network (PTN) to an
unweighted network by space L and space P method. The adjacency matrix is used
to express this network, in which 1 denotes connection between two vertices
and 0 denotes disconnection. According to the complex theory, the statistical
characteristics (including average clustering coefficient, average shortest
path length, and so on) of the real PTN of Hangzhou are analyzed. By the
shortest path algorithm of matrix multiplication, all the least transfer
routes between any two bus stations of Hangzhou are gotten. Then the PTN of
Hangzhou is modeled to a weighted network using the straight-line distances
between the bus stations which are computed by every station’s longitudes and
latitudes as the weights. To compare the weights (namely the straight-line
distances) of all the least transfer routes, the transfer routes between any
two bus stations which not only have the least transfer times but also the
shortest straight-line distances are obtained. Finally, by some practical bus
stations of Hangzhou, this transfer method is validated.
Keywords:
Public transport network; Small-world; Weighted network; Transfer route;
Matrix multiplication
Issue 4, Volume 10,
April 2011
Title of the Paper: Robots
Implementation for Odor Source Localization Using PSO Algorithm
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Authors: Jatmiko W,
Jovan F, Dhiemas R.Y.S, T. Fukuda, K. Sekiyama
Abstract: Research topics in robotic application is quite varies but one of
the most interesting topic is odor source localization. This research combine
the robot ability to recognize odor and track the movement so that robotcan
find the source. Most of the research are done to improve the algorithm to
localize the source by using simulation software. This paper tries to verify
the robustness of one of the localization method known as Particle Swarm
Optimization (PSO) in the real-world implementation. This paper will shows
robot model that used in the experiment and also discuss the architecture to
implement robot behavior. A group of mobile robots equipped with wireless
communication device and odor sensors is employed. The experiment is conduct
in area of 488cm x 488cm with dynamic odor source in one end. The experiment
also used a set of camera to track robots position. The experiement result
verifies that PSO is technically sound for real-world odor source
localization. In this experiment, PSO can localized the source in 360 seconds
or bellow.
Keywords:
PSO, Al-Fath, Odor Source
Title of the Paper: A Doubly-Excited
DC- to- 3-Phase AC Buck-Boost Converter Gives Sinusoidal Waveforms: Design,
Simulation & Control
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Authors: M. Ezzat
Abstract: This paper presents a new topology for converting a DC voltage to a
3-phase AC one. The proposed converter is excited from two separate DC
supplies so the term "Doubly-Excited". The most important features of the
proposed converter are the output voltage (AC Voltage) is lower or higher than
the input one (DC Voltage), controllable voltage and frequency, and the output
voltage and current are approximately sinusoidal which means low harmonics
content. Also, the paper presents the simulation of the proposed converter in
different modes of operation under control to show the effectiveness of the
proposed control strategy.
Keywords:
Boost, Control, DC- to -3-phase AC Converter, Design, Simulation
Title of the Paper: An Enhanced Load
Transfer Scheme for Power Distribution Systems Connected with Distributed
Generation Sources
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Authors: Wen-Chih Yang,
Wei-Tzer Huang
Abstract: This paper presents an enhanced load transfer scheme for power
distribution systems connected with distributed generation sources. Load
transfer is an important approach to improve the reliability of power
distribution systems. The proposed load transfer scheme takes into account the
effects of distributed generation sources on power distribution systems.
Hence, it is more useful than conventional load transfer scheme. In this
paper, the procedures of conventional and proposed load transfer scheme are
addressed in detail. Two example systems for computer simulation were
constructed and several simulation scenarios were carried out by this work.
Simulation results shown in this paper clearly indicate the troubles of
conventional load transfer scheme and the practicability of the proposed load
transfer scheme.
Keywords:
Load transfer, Distribution system, Distribution feeder, Distributed
generation source, Interconnection
Issue 5, Volume 10,
May 2011
Title of the Paper: A Preventive
Control Model for Static Voltage Stability and Thermal Stability based on
Power Transfer Capabilities of Weak Branches
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Authors: Wei Yan,
Xiuqiong Hu, Juan Yu, Wenyuan Li
Abstract: A preventive control model for static voltage stability and thermal
stability is presented using the apparent power constraints on weak branches
as both static voltage stability constraints and thermal stability
constraints. Firstly, a localized line-based voltage stability index is
selected to determine the weak branches as well as their power transfer
capabilities and the critical contingencies. A static security analysis
method, which is based on PQ decouple method, is adopted to obtain the
quadratic apparent power expressions of weak branches following each critical
contingency. Then, the apparent power constraints on weak branches are
established combining the power transfer capabilities and the apparent power
expressions of weak branches. The proposed preventive control model has a
quadratic form and can be solved by the predictor-corrector primal dual
interior method. The simulation results for three IEEE test systems
demonstrate the correctness and effectiveness of the proposed preventive
control model.
Keywords:
Preventive control, Static voltage stability, Thermal stability, Weak branch,
Apparent power constraint, Quadratic optimal model
Title of the Paper: About the
Definition of Parameters and Regimes of Active Two-Port Networks with Variable
Loads on the Basis of Projective Geometry
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Authors: Penin Alexandr
Abstract: Disadvantages of some well- known methods of analysis of electric
circuits with variable loads are analyzed. To interpret a mutual influence of
the loads, some methods of the projective geometry are used. The application
of the projective coordinates allows receiving the equation of the active
two-port network in a normalized or relative form as well as defining the
scales for the currents and conductivity of the loads. Such approach makes it
possible to estimate the qualitative characteristics of the current regimes,
to compare the regime efficiency of the different circuits. The formulas of
the recalculation of the currents, which possess the group properties at
change of conductivity of the loads, are obtained. It allows expressing the
final values of the currents through the intermediate changes of the currents
and conductivities. The generalized equivalent generator of the active
two-port network in the form of the passive two-port network and a set of the
sources of a current and voltage is proposed. The parameters of these sources
do not depend on certain conductivities of the passive two-port network.
Keywords:
Thevenin’s theorem, load characteristics, projective geometry, two-port
networks
Title of the Paper: SVC Implementation
Using Neural Networks for an AC Electrical Railway
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Authors: Saeid Veysi
Raygani, Bijan Moaveni, Seyed Saeed Fazel, Amir Tahavorgar
Abstract: This paper presents an on-line method for implementation of a static
var compensator (SVC) in a real ac autotransformer (AT)-fed electrical railway
for reactive power compensation using Neural Networks (NN). Genetic algorithm
(GA) can be the off-line minimizing function for reactive power compensation.
Consequently, the nonlinear auto-regressive model with exogenous Inputs
networks in series-parallel arrangement (NARXSP) is implemented as a predictor
and methodology in order to diminish calculation time and making this method
practicable. To study load flow and reactive power compensation for this
unique system, forward/backward sweep (FBS) load flow method is applied.
MATLAB software is used for programming and simulations.
Keywords:
Neural network (NN), reactive power compensation, static var compensator
(SVC), genetic algorithm (GA), AC electrical railways load flow,
forward/backward sweep (FBS)
Issue 6, Volume 10,
June 2011
Title of the Paper: Investigation Life
Time Model of 22 kV XLPE Cable for Distribution System Applications in
Thailand
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Authors: Boonruang
Marungsri, Anucha Rawangpai, Nimit Chomnawang
Abstract: Cross-linked polyethylene (XLPE) high voltage cables have been
widely used in power transmission and distribution systems. Ageing
deterioration of XLPE insulating material can not be avoided because it is
made of polymeric material. This paper present results of artificial ageing
test of 22 kV XLPE cable for a distribution system application in Thailand.
XLPE insulating material of 22 kV cable was sliced to 60-70 ìm in thick and
subjected to AC high voltage stress at 23?C, 60?C, 75?C and 90?C. The
specimens were tested under different electrical stress levels varying from
50kV/mm to 130kV/mm. Testing voltage was constantly applied to the specimen
until breakdown. Five specimens were tested at each temperature and voltage
stress level. Breakdown voltage and average time to breakdown were used to
evaluate life time of insulating material. Furthermore, the physical model by
J. P. Crine for prediction life time of XLPE insulating material was adopted
as life time model and was determined in order to compare with the
experimental results. In addition, Fourier transform infrared spectroscopy
(FTIR) for chemical analysis and scanning electron microscope (SEM) for
physical analysis were conducted on the tested specimens.
Keywords:
Artificial accelerated ageing test, XLPE cable, distribution system,
insulating material, life time, life time model
Title of the Paper: Development of an
Advanced Embedded System for Description of Electrophysiological Phenomena in
Ornamental Plants by Biosignals Processing
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Authors: Kalovrektis K.,
Ganetsos Th., Shammas N. Y. A., Taylor I., Lykas Ch., Andonopoulos I., Lekakis
I.
Abstract: Extracellular electrical signals that are produced from plants have
different patterns depending on factors that may cause stress such as water
deficiency, nutrient shortages, high salinity level in the root environment
etc. In practice, growers and greenhouse control systems acts against the
stress factor when visible symptoms are observed, or when the measured values
of parameters related to the stress are outside certain limits during a
pre-defined period. However, the decrease in plant growth has already begun
during this period with consequences for production. The objective of this
work is the development of an advanced embedded wireless sensor to detect
electrophysiological phenomena in order to investigate the correlation of
biosignal patterns to salinity stress in ornamental plants. This embedded
system could be used to improve the efficiency of irrigation control systems
especially in soilless cultures. For this reason an integrated embedded
hardware was designed for plant biosignal measurements. In order to avoid
white Gaussian noise (WGN caused from 50 Hz power line noise as well as the
noise of the electrical devices operating inside the greenhouse), the IEEE
802.15.4 protocol was used for wireless communication to the embedded systems.
Electrical potential difference in leaves of single stem Chrysanthemum
(Chrysanthemum moriflorum) plants grown in soilless culture and irrigated with
low and high electrical conductivity (EC) nutrient solution were measured
using the embedded wireless system and a traditional wire data acquisition
system (DAQ). The measurements are recorded for a period of 4 days, via a data
acquisition system and processed using LabVIEW code. The results show that
biosignal measurements on plants, obtained with the use of the design wireless
embedded system have a negligible error in contrast to wired data acquisition,
since these are not affected by RF and other similar signal noise. The
experimental measurements showed that there is a significant correlation
between the mean voltage value of the measured biosignal ( )and the EC level
of the substrate where the plants were grown.
Keywords:
Biosignal, chrysanthemum, Ag/AgCl, wireless sensor, amplifier, salinity
stress, electrical conductivity
Title of the Paper: Possible Solution
of Decoupling and Invariance of Multi-variable Control Loop by Using Binding
and Correction Members
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Authors: Pavel Navratil,
Libor Pekar
Abstract: The paper describes one of possible methods how to control of
multi-variable control loops. In this case the used method of control uses the
so called main controllers, binding members and correction members. This
control method combines classical approach for ensuring decoupling of
multi-variable control loop by means of binding members and the use of the
correction members for ensuring invariance of multi-variable control loop by
means of two approaches. Main controllers can be proposed by arbitrary
single-variable synthesis method. Simulation verification of the used control
method is carried out for example of three-variable loop of a steam turbine.
Keywords:
Decoupling of control loop, control, invariance of control loop, simulation
Issue 7, Volume 10,
July 2011
Title of the Paper: A Robust
Asynchronous Early Output Full Adder
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Authors: Padmanabhan
Balasubramanian
Abstract: A robust asynchronous full adder design corresponding to early
output logic, synthesized using the elements of a standard cell library is
presented in this paper. As the name suggests, the adder ensures gate orphan
freedom and neatly fits into the self-timed system architecture. In comparison
with many of the indicating full adder designs, which can be embedded in the
self-timed system, it is found that the proposed full adder enables reduction
in latency by 20.7%, occupies lesser area by 15.4% and features minimized
average power dissipation by 8.6% against the best design metrics of its
counterparts. These design estimates correspond to simulation results of the
32-bit carry-ripple adder circuit; derived by targeting a high-speed 130nm
bulk CMOS process technology. Also, the proposed full adder facilitates a
faster reset and the return-to-zero for the fundamental carry-propagate
topology is achieved with only two full adder delays.
Keywords:
Full adder, Asynchronous design, Early propagation, Indication, Standard
cells, CMOS process
Title of the Paper: An Efficient EPI
and Energy Consumption of 32 bit ALU Using Shannon Theorem Based Adder
Approach
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Authors: C. Senthilpari,
G. Ramanamurthy, P. Velrajkumar
Abstract: This paper proposed two full adder circuits such as mixed Shannon
and Shannon theorem based adder circuits. The mixed adder circuit developed by
using MCIT for the sum operation and Shannon technique for carry and other one
designed completely by using Shannon theorem. The ALU circuit consists of AND,
OR, multiplexer and adder circuits that are designed by using proposed Shannon
theorem. The 32-bit ALU circuits are analyses by BSIM 4 parameter analyzer.
The power dissipation of total circuit, propagation delay and area are
analyzed for 32 bit ALU. The binvert Shannon adder based ALU circuit gives
better performance in terms of power dissipation, propagation delay, and
throughput than bit-sliceALU circuit.
Keywords:
ALU, MCIT, Shannon theorem, CPL, Power Dissipation, Throughput
Title of the Paper: Comparison of
Lyapunov Function for Different Strategies of Optimization of Analogue
Networks using Parallel Computing
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Authors: Alexander
Zemliak, Antonio Michua
Abstract: The problem of designing of analog network for a minimal computer
time has been formulated as the functional minimization problem of the control
theory. The design process in this case is formulated as the controllable
dynamic system. The optimal sequence of the control vector switch points was
determined as a principal characteristic of the minimal-time system design
algorithm. The conception of the Lyapunov function was proposed to analyze the
behavior of the process of designing. The special function that is a
combination of the Lyapunov function and its time derivative was proposed to
predict the design time of any strategy by means of the analysis of initial
time interval of the process of network optimization. The parallel computing
serves to compare the different strategies of optimization in real time and to
select the best strategy that has the minimal computer time. This approach
gives us the possibility to select the quasi optimal strategy of network
optimization by analyzing the initial part of the total design process only.
Keywords:
Minimal-time system designing, control theory application, network
optimization, Lyapunov function, parallel computing
Issue 8, Volume 10,
August 2011
Title of the Paper: On Brayton-Moser
Network Decomposition and State-Space Energy based Generalization Of
Nose-Hoover Dynamics
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Authors: Josef Hrusak,
Milan Stork, Daniel Mayer
Abstract: This paper deals with generalization of the Brayton-Moser network
decomposition and related structural properties to a relatively large class of
finite dimensional strictly causal systems, which can be described in the
state-space representation form. The resulting energy-metric function is
defined for dissipative systems and is induced by the output signal
dissipation power. It is demonstrated that such a power-oriented approach
determines both, the structure of a system representation as well as the
corresponding system state space topology. A special form of physically
correct internal structure of an equivalent state space representation has
been derived as a natural consequence of strict causality, the state-space
energy conservation, dissipativity assumption and the state minimality
requirement.
Keywords:
State-space energy, decomposition, dissipation power, active power, reactive
power
Title of the Paper: Full-Graph Solution
of Switched Capacitors Circuits by Means of Two-Graphs
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Authors: Bohumil Brtnik
Abstract: Circuits with switched capacitors are described by a capacitance
matrix. As there are also graph methods of circuit analysis in addition to
algebraic methods, it is clearly possible in theory to carry out an analysis
of the whole switched circuit in two-phase switching exclusively by the graph
method as well. The phase of switching are called even (E) and odd (O), not 1
and 2 to avoid confusion between the sign of the phases and of the nodes. For
this purpose it is possible to plot a Mason graph of a circuit, use two graphs
to reduce oriented graphs for all the four phases of switching, and then plot
a summary MC-graph from charge and voltage graphs. Summary MC-graph is now
constructed by the incomplete common skeletons of the V-graph and the Q-graph
in all four phases, branches obtained for EO and OE phase are drawn between
these nodes, while their resulting transfer is multiplied by 2 1 -z to express
the delay between the two phases. This summary MC-graph can then be
interpreted by the Mason’s relation to provide transparent voltage transfers,
and so it is possible to reach the final result a quite fully graphically.
This method can be used for circuits containing operational amplifier with the
break point frequency, too, but summa graph is rather complicated in this
case, because this description is based on the modified nodal method, where
the number of nodes is remains.
Keywords:
Switched capacitors, two-graphs, Mason-Coates graph, summa graph, Mason/s
rule, break point frequency
Title of the Paper: ASIC Implementation
of High Speed Processor for Calculating Discrete Fourier Transformation using
Circular Convolution Technique
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Authors: P. Saha, A.
Banerjee, A. Dandapat, P. Bhattacharyya
Abstract: The improvement in speed and power for calculating discrete Fourier
transformation using circular convolution is well established, but all the
work so far been reported are at FPGA (gate) level. In this paper ASIC
implementation of high speed processor for calculating Discrete Fourier
Transformation (DFT) based on circular convolution architectures is reported
for the first time. The IEEE-754 single precision format was considered for
the representation of the twiddle factors. The improvement of the speed for
floating point multiplication/addition was achieved by canonical sign digit
implementation methodology, which reduced the stages of operation
significantly. The functionality of these circuits was checked and performance
parameters such as propagation delay, dynamic switching power consumptions
were calculated by spice spectre using standard 90nm CMOS technology. The
implementation methodology ensure substantial reduction of propagation delay
in comparison with systolic array and memory based implementation, most
commonly used architectures, reported so far, for DFT processors. The
propagation delay of the resulting 16 point DFT processor is only 23.79µs
while the power consumption of the same was 14.32mW only for a layout area of
~12mm2. Almost 50% improvement in speed from earlier reported DFT processors,
e.g. systolic array and memory based implementation methodology, has been
achieved.
Keywords:
DFT, FFT, Circular convolution, Multiply and accumulate (MAC), Canonical sign
digit (CSD) adder, CSD Multiplier
Issue 9, Volume 10,
September 2011
Title of the Paper: A New CMOS Current
Controlled Oscillator with Minimum Phase Noise Based on a Low Parasitic
Resistance CCII
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Authors: Samir Ben
Salem, Achwek Ben Saied, Dorra Sellami Masmoudi, Mourad Loulou
Abstract: In this paper we present a design of a minimum phase noise current
controlled oscillator in CMOS technology. Owing to their high degree of
controllability, the second generation current conveyer is used as a basic
block for our oscillator. Thus, the first step in our design was to improve
static and dynamic behaviour of second generation current conveyers. We
present therefore a design of CMOS class AB second generation current
conveyors. The translinear implementation in CMOS technology was first studied
and then a considerable improvement of the parasitic series resistance on port
X is done by presenting a structure of CCII. With a control current of 300 ìA,
a reduction of RX by a factor of 10 is observed leading to a notable
improvement of the frequency behaviour. This improved CCII version was used as
a basic building block in the design of a new current controlled oscillator
covering [100MHz-600MHz] frequency is presented. Phase noise characteristics
of the presented oscillator are investigated. We present then a new
methodology of modelling and optimisation of phase noise of current controlled
oscillators for CMOS process. This optimization strategy leads to a minimum
phase noise acting on device geometries and design sources. PSpice simulation
results are performed using CMOS 0.35 ìm process of AMS.
Keywords:
Current Controlled Oscillators, Standard CMOS current conveyor, CCII, cascode
structure, Conveyor characterization, RF application, Phase noise optimisation
Title of the Paper: Investigation of
Some Quite Interesting Divisibility Situations in a Signature Analyzer
Implementation
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Authors: Afaq Ahmad
Abstract: When designing error detecting and correcting systems, cryptographic
apparatus, scramblers and other secure, safe and authenticated communication
and digital system response data compression devices, the division of
polynomials are frequently involved. Commonly, the process of division is
implemented by using hardware known as Linear Feedback Shift Registers
(LFSRs). In digital system testing the technique of Built-In Self Test (BIST)
uses this LFSR based division process for response data compression and is
popularly known as Signature Analyzer (SA). This paper presents a simulation
experiment on the effectiveness study of the SA schemes. The finding of the
results of the simulation study reveals that in SA implementation; in general
the uses of primitive characteristic polynomials are the best. However, the
study further investigates that the use of some critical primitive
characteristic polynomials may reverse the effectiveness of the SA schemes
i.e. lead to observe maximum aliasing errors.
Keywords:
Signature Analyzer, Linear Feedback Shift Registers, Built-In Self-Test, VLSI,
Aliasing Errors, Characteristic Polynomial, Primitive Polynomials, Polynomial
Division, Cyclic Redundancy Check
Title of the Paper: Simulation and
Research on Three-Phase Parallel PFC with Feed-Forward Compensation
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Authors: Chen Qian, He
Mingzhi, Trillion Q. Zheng
Abstract: In order to enhance the power factor and minimize the complexity of
control strategy, the analysis of a novel three-phase parallel power factor
correction with feed-forward compensation is presented. According to the
working principle of the topology, hysteresis current control strategy has
been proposed for the bi-boost crossing converter. The simulation results
verify the stability of the system. As a result, the time sequence of the
system is so simple that the switches can be easily controlled to achieve
stable output voltage, ideal power factor and current harmonic, while only
twenty percents of the total power passes through the Boost converter. In
order to achieve ideal power factor and low current harmonic, the output power
should be constant.
Keywords:
Three-phase power factor correction, Feed-forward compensation, Low current
harmonic, Hysteresis current control, Bi-boost crossing converter,
Constant-power load
Issue 10, Volume
10, October 2011
Special Issue: Fuzzy Systems and
Applications
Editors: Nikos E. Mastorakis, Valeri Mladenov
Title of the Paper: Advanced Modelling
of Complex Processes by Fuzzy Networks
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Authors: Alexander
Gegov, Nedyalko Petrov, Boriana Vatchova, David Sanders
Abstract: This work presents an application of the novel theory of rule based
networks for building models of processes characterised by uncertainty,
non-linearity, modular structure and internal interactions. The application of
the theory is demonstrated for a flotation process in the context of
converting a multiple rule based system into an equivalent single rule based
system by linguistic composition of the individual rule bases. During the
conversion process, the transparency of the multiple rule based system is
fully preserved while its accuracy is improved to a level comparable with the
accuracy of the single rule based system.
Keywords:
Hierarchical model, network model, data simulation, fuzzy logic, fuzzy
systems, process model, input/output models, systems evaluation, knowledge
base
Title of the Paper: Hierarchical
Clustering in Power System Based on Fuzzy Transitive Closure
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Authors: Shu-Chen Wang
Abstract: This paper presents the applications of hierarchical clustering to
the generators in a power system. A useful application of fuzzy mathematics is
that the correction of clustering results and determination of whether it can
obtain correct transitive closure. Thus, the fuzzy transitive closure plays an
important role in hierarchical clustering. Based on the fuzzy relation matrix,
the hierarchical cluster analysis can be achieved by using firstly computing a
transitive closure matrix on which serial á-cut operations are to be
performed. A specific feature of the proposed method is that the hierarchical
clustering work can be performed in parallel with the algorithm. The proposed
method retains the correctness of transitive closure by reducing the
computation complexity. Results from applying the method to a power system are
demonstrated to show the validity and effectiveness of the proposed method.
Keywords:
Hierarchical Clustering, Power System, Fuzzy Transitive Closure, Fuzzy
Similarity Relation, á-cut Operation, Complexity
Title of the Paper: The Optimal
Interval Partition and Second-Factor Fuzzy Set Bi on the Impacts of Fuzzy Time
Series Forecasting
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Authors: Chi-Chen Wang,
Yueh-Ju Lin, Yu-Ren Zhang, Hsien-Lun Wong
Abstract: This study uses two sets of Taiwanese data, the export values as the
prediction varialbe and its foreign exchange spot rates as the auxiliary
variable, to discuss two important issues of forecasting effects in the fuzzy
time series analysis by using One- and Two-factor models. The first issue is
the relation between the optimum number of partition equal intervals and
forecasting error. The second issue is the setting of fuzzy matrix (Bi) in the
model to compare its impacts on forecasting error when it is static or
dynamic. The above two issues are investigated with the empirical results.
First, the optimum number of partition equal intervals is to select 14
intervals for the information to have the smallest forecasting error in all
models for one- or two-factor, or different number of window basis selected.
However, if partitioning the information into more than 14 equal intervals,
the forecasting error can not be reduced but presents a waving pattern.
Second, when the information period is longer and if the selecting window
basis is two, under any number of partition intervals, the forecasting error
is always smaller for the dynamic Bi than for the static one. However, when
the information period is shorter and the window basis is two or three, only
partitioning into five or eight equal intervals, the forecasting error will
also be smaller for the dynamic Bi.
Keywords:
Fuzzy tine series, Two-factor model, Interval partition, Fuzzy relationship
matrix, Window base, Taiwan exports, MSE
Title of the Paper: Determination of
Crystallizer Service Life on Continuous Steel Casting by Means of the
Knowledge System
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Authors: Jiri David,
Milan Vrozina, Zora Jancikova
Abstract: In this paper there is described the input analysis of the
crystallizer service life control problem for creation and exploitation of the
software product in order to apply the knowledge systems complemented by the
continuous diagnostics that will significantly reduce the human factor
involvement in providing the manufacturing equipments inspection, in
identification of technical condition and failures of equipments,
specification of failures prediction and possibly also in failures elimination
through a partial or total automation.
Keywords:
Knowledge system, fuzzy systems, prediction, reliability, lifetime, steel
industry
Issue 11, Volume
10, November 2011
Title of the Paper: Study on the New
Topology of Power Electronic Transformer
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Authors: Zhibing Wang,
Kushan Yu, Xiaoxin Zhou
Abstract: This paper presents a mixed topology of Power Electronic Transformer
based on Three-Level converter and H-Bridges. It does take into account two
conditions, which includes the development of power electronic devices and
manufacturing level of high-frequency transformer in the future. First the
paper introduced the fundamentals of PET, and then studied on the mathematical
model of the new topology in detail. In order to verify the validity of the
new topology, the model of Power Electronic Transformer was simulated by
MATLAB/PST toolbox, and indicated the inherent problem, which is unbalance of
the neutral point voltage. Therefore, the paper proposed control strategies to
maintain the balance, and suppress the effect of ripple voltage on common DC
bus. Eventually simulations and experimental results validate the feasibility
of the new topology and control strategies.
Keywords:
Distributed Generations (DGs), Intelligent Universal Transformer (IUT), Power
Electronic Transformer (PET), Solid State Transformer (SST), Space Vector
Modulation (SVM), Power Factor Correction (PFC), Renewable Energy Source
(RES), Smart Grid (SG)
Title of the Paper: Investigation of
Transient Models and Performances for a Doubly Fed Wind Turbine under a Grid
Fault
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Authors: Mingyu Wang,
Bin Zhao, Hui Li, Chao Yang, Renjie Ye, Z. Chen
Abstract: In order to investigate the impacts of the integration of wind farms
into utilities network, it is necessary to analyze the transient performances
of wind turbine generation systems (WTGS) with the appropriate transient
models. According to the grid code requirements for a wind turbine with doubly
fed induction generator (DFIG), the assessments of the impact on the
electrical transient performances were investigated for the doubly fed wind
turbine with different representations of wind turbine drive-train dynamics
models, different initial operational conditions and different active crowbar
trip time. Firstly, the different mathematical models of the doubly fed wind
turbine were presented, including the electromagnetic transient models of
DFIG, a one-mass lumped model, a two-mass shaft flexible model of the wind
turbine drive train system, and the power decoupling control strategies of the
grid-side converter and the rotor-side converter of DFIG. Secondly, the
transient performances of the presented doubly fed wind turbine under a grid
fault were compared and evaluated with different equivalent models, parameters
and initial operational conditions. And thirdly, the effects of the active
crowbar on the transient performances of the doubly fed wind turbine were also
investigated, with the possible reasonable trip time of crowbar. The
investigation have shown that the transient performances are closely
correlated with the wind turbine drive train models, initial operational
conditions, key parameters of wind turbine, and trip time of the crowbar
circuit.
Keywords:
Wind power, Doubly fed induction generator, Drive train, Transient
performance, Crowbar
Title of the Paper: A Fast Iterative
Shrinkage-Thresholding Algorithm for Electrical Resistance Tomography
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Authors: Zhang Lingling,
Wang Huaxiang, Xu Yanbin, Wang Da
Abstract: Image reconstruction in Electrical Resistance Tomography (ERT) is an
ill-posed nonlinear inverse problem. Considering the influence of the sparse
measurement data on the quality of the reconstructed image, the l1 regularized
least-squares program (l1 regularized LSP), which can be cast as a second
order cone programming problem, is introduced to solve the inverse problem in
this paper. A normally used method of implementing the l1 regularized LSP is
based on the interior point method whose main drawback is the relatively slow
convergence speed. To meet the need of high speed in ERT, the fast iterative
shrinkage-thresholding algorithm (FISTA) is employed for image reconstruction
in our work. Simulation results of the FISTA and l1_ls algorithm show that the
l1 regularized LSP is superior to the l2 regularization method, especially in
avoiding the over-smoothing of the reconstructed image. In addition, to
improve the convergence speed and imaging quality in FISTA algorithm, the
initial guess is calculated with the conjugate gradient method. Comparative
simulation results demonstrate the feasibility of FISTA in ERT system and its
advantage over the l1_ls regularization method.
Keywords:
Electrical resistance tomography; l1 regularization method; interior-point
method; iterative shrinkage-thresholding algorithm; linear inverse problem
Issue 12, Volume
10, December 2011
Title of the Paper: A Novel Technique
to Reduce Write Delay of SRAM Architectures
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Authors: Swapnil Vats,
R. K. Chauhan
Abstract: This paper presents a novel circuit technique for improving the
write delay of an SRAM cell. The technique is common for all the SRAM
architecture. It utilizes a PMOS between power supply rail and the SRAM cell
and an NMOS between SRAM cell and ground. The simulation results for write
delay, SNM and power dissipation were presented with and without application
of proposed technique on two different SRAM architectures. Significant
improvements on write delay and power dissipation were noticed for the
proposed modified SRAM architectures with less impact on SNM.
Keywords:
SRAM, SNM, NMOS, PMOS, DRAM, Butterfly curve
Title of the Paper: Comparative Study
of Three Shapes of DGS Pattern and Design of Compact Microstrip Low-Pass and
Band-Pass Filters
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Authors: Mouloud
Challal, Frederick Labu, Mokrane Dehmas, Arab Azrar
Abstract: In this paper, three types of defected ground structure (DGS) units
which are triangular-head (TH), rectangular-head (RH) and U-shape (US) are
investigated and their characteristics are compared each other. Further, they
are used in the design of low-pass filters (LPF) and band-pass filters (BPF)
and the obtained performances are examined. The LPF employing RS-DGS geometry
presents the advantages of compact size, low-insertion loss and wide stopband
compared to the other filters. It provides a cutoff frequency at 2.5 GHz, a
largest rejection band width of 20 dB from 2.98 to 8.76 GHz, a smallest
transition region and a smallest sharpness response at the cutoff frequency.
The BPF based on RS-DGS has the highest bandwidth (BW) of about 0.74 GHz and
the lowest center frequency of 3.24 GHz whereas the other BPFs have BWs less
than 0.7 GHz.
Keywords:
Defected ground structure (DGS), low-pass filter (LPF) and band-pass filter
(BPF)
Title of the Paper: Transmission Line
Protection based on Travelling Waves
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Authors: Anuradha S
Deshpande, Grishma S. Shah
Abstract: Major problem of tripping signal of a relay based on steady state
component does not warranty faster tripping schemes for protection of extra
high voltage transmission lines. Proposed work has made an attempt to find
solution to the problem of fault detection and location by relay using post
fault high frequency signals. Transmission line protection using travelling
waves generated at the time of fault are used as trip signals of a travelling
wave relay.Paper has made an attempt to obtain travelling waves components in
the form of forward wave and backward waves from post fault components of
voltage and current. These have been used for getting 0, á and â components
using clarke’s transformation which further reduces to df and dr respectively
forming trip signals for tripping travelling wave relay. The proposed
methodology is tested on a 500KV test system for different types of fault and
different fault locations.Results obtained by proposed methodology are in
total comparison to those obtained by co-relation technique described in [1].
Keywords:
Travelling waves, transmission line protection, postfault voltage, surge
impedence, relaying signals
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