Iranian Journal of Electrical & Electronic Engineering
http://ijeee.iust.ac.ir
Iranian Journal of Electrical and Electronic Engineering - Journal articles for year 2005, Volume 1, Number 2Yektaweb Collection - http://www.yektaweb.comen2005/4/12New adaptive interpolation schemes for efficient meshbased motion estimation
http://ijeee.iust.ac.ir/browse.php?a_id=45&sid=1&slc_lang=en
Motion estimation and compensation is an essential part of existing video coding
systems. The mesh-based motion estimation (MME) produces smoother motion field, better
subjective quality (free from blocking artifacts), and higher peak signal-to-noise ratio
(PSNR) in many cases, especially at low bitrate video communications, compared to the
conventional block matching algorithm (BMA). However, the iterative refinement process
of MME is computationally much costly and makes the method impractical in real- (or near
real-) time systems. Also, eliminating the iterative refinement step deteriorates the motion
estimation result. In this paper, we propose motion adaptive interpolation schemes for noniterative
MME, which use BMA to compute the motion vectors (MVs) of mesh nodes. The
proposed algorithm aims at compromising the MME and BMA by modifying the
interpolation patterns (IPPs) of the MME in an adaptive manner, based on the MVs of
mesh nodes. Experimental results show notable rate-distortion improvement over both
BMA and conventional non-iterative MME, with acceptable visual quality and system
complexity, especially when applied to sequences with medium to high motion activities. Shohreh KasaeiAdaptive search area for fast motion estimation
http://ijeee.iust.ac.ir/browse.php?a_id=46&sid=1&slc_lang=en
In this paper a new method for determining the search area for motion estimation
algorithm based on block matching is suggested. In the proposed method the search area is
adaptively found for each block of a frame. This search area is similar to that of the full
search (FS) algorithm but smaller for most blocks of a frame. Therefore, the proposed
algorithm is analogous to FS in terms of regularity but has much less computational
complexity. To find the search area, the temporal and spatial correlations among the
motion vectors of blocks are used. Based on this, the matched block is chosen from a
rectangular area that the prediction vectors set out. Simulation results indicate that the
speed of the proposed algorithm is at least 7 times better than the FS algorithm. Shadrokh SamaviGeneration scheduling in a competitive environment
http://ijeee.iust.ac.ir/browse.php?a_id=47&sid=1&slc_lang=en
Electric power restructuring offers a major change to the vertically integrated
monopoly. The change manifests the main part of engineers’ efforts to reshape the three
components of today’s vertically integrated monopoly: generation, distribution and
transmission. In a restructured environment, the main tasks of these three components will
remain the same as before, however, to comply with FERC orders, new types of unbundling,
coordination and rules are to be established to guarantee competition and non-discriminatory
open access to all users.
This paper provides the generation schedule of a GENCO in a deregulated power system. It is
shown that the goal of generation schedule in the new structure is different from the traditional
centralized power systems. The modeling of generation scheduling problem in a competitive
environment is demonstrated by taking into account the main purposes of GENCOs which are
selling electricity as much as possible and making higher profit. The GENCOs of an area are
introduced via a model whose objective function consists of hourly spot market price as income
and different kinds of costs. The constraints are the general ones of such a problem e.g.
minimum up/down time, minimum and maximum generation and ramp rate. Using one of the
classical optimization methods, the hourly generation schedule of the generating units will be
obtained in this competitive environment. The results of this section will be used by ISO. The
ISO will finalize the schedules of GENCOs by taking into account the technical considerations
like the power flow of transmission lines. The model and the optimization methods are
implemented on IEEE-RTS benchmark with 24 buses and 32 generating units. H. MonsefEffective transient stability assessment based on composite indices
http://ijeee.iust.ac.ir/browse.php?a_id=48&sid=1&slc_lang=en
This paper presents a new composite index to analyze power system transient
stability. Contingency ranking in power system transient stability is a complicated and time
consuming task. To prevail over this difficulty, various indices are used. These indices are
based on the concept of coherency, transient energy conversion between kinetic and
potential energy and three dot products of the system variables. It is well known that some
indices work better than others for a particular power system. This paper along with test
results using two practical 230 kV Sistan and 400 kV Khorasan power system in Iran, and 9
bus IEEE test system demonstrates that combination of indices provides better ranking than
a single one. In this paper two composite indices ( CI ) is presented and compared. One
composite index is based on Least Mean Square algorithm (LMS) and other based on
summing indices by equal weights. Numerical simulations of the developed index,
demonstrate that composite index is more effective than other indices. S.JadidAnalysis of converter-permanent magnet synchronous machine set by improved average-value modeling
http://ijeee.iust.ac.ir/browse.php?a_id=49&sid=1&slc_lang=en
Dc excitation of the field winding in a synchronous machine can be provided by
permanent magnets. Permanent magnet synchronous machine (PMSM) can offer simpler
construction, lower weight and size for the same performance, with reduced losses and higher
efficiency. Thanks to the mentioned advantages these motors are widely used in different
application, therefore analysis and modeling of them, is very important. In this paper a new, fast
and simple method is presented to study performance of a PMSM connected to the converter.
For this purpose, average-value modeling and related analytical relations which leads to the
desired characteristics such as electromagnetic torque, dc current and dc voltage is presented
and applied to PMSM & converter system. The advantage of this model lie in reduction of
computation time compares to the other dynamic models while keeping accuracy quite
acceptable. This model is applicable for studying the steady-state performance of systems as
well as dynamic performance. A.VahediA comprehensive model using modified Zeeman model for generating ECG signals
http://ijeee.iust.ac.ir/browse.php?a_id=50&sid=1&slc_lang=en
Developing a mathematical model for the artificial generation of
electrocardiogram (ECG) signals is a subject that has been widely investigated. One of its
uses is for the assessment of diagnostic ECG signal processing devices. So the model
should have the capability of producing a wide range of ECG signals, with all the nuances
that reflect the sickness to which humans are prone, and this would necessarily include
variations in heart rate variability (HRV). In this paper we present a comprehensive model
for generating such artificial ECG signals. We incorporate into our model the effects of
respiratory sinus arrhythmia, Mayer waves and the important very low frequency
component in the power spectrum of HRV. We use the new modified Zeeman model for
generating the time series for HRV, and a single cycle of ECG is produced using a radial
basis function neural network. A AyatollahiImpedance bandwidth optimization of double slots circular patch antenna using genetic algorithm and the Interface Fuzzy Logic
http://ijeee.iust.ac.ir/browse.php?a_id=51&sid=1&slc_lang=en
A modified circular patch antenna design has been proposed in this paper, the
bandwidth of this antenna is optimized using the genetic algorithm (GA) based on fuzzy
decision-making. This design is simulated with HP HFSS Program that based on finite element
method. This method is employed for analysis at the frequency band of 1.4 GHz- 2.6 GHz. It
gives good impedance bandwidth of the order of 15.5% at the frequency band of 1.67GHz-
1.95GHz and 10.6% at 2.23GHz- 2.48GHz. It means that impedance bandwidth increases above
4.9% than the impedance bandwidth of ordinary circular patch antennas and band width rise
from 1.78GHz- 1.98GHz (10.6%) to 1.67GHz- 1.95GHz (15.5%) and 2.23GHz- 2.48GHz
(10.6%). The antenna fabricated with two slots on circular patch antenna. The measured results
of the optimized antenna validate a high compatibility between the simulation and the
measurements. F. Hojjat Kashani