OTHERS_CITABLE
A Unified Framework for Delineation of Ambulatory Holter ECG Events via Analysis of a Multiple-Order Derivative Wavelet-Based Measure
In this study, a new long-duration holter electrocardiogram (ECG) major events detection-delineation algorithm is described which operates based on the false-alarm error bounded segmentation of a decision statistic with simple mathematical origin. To meet this end, first three-lead holter data is pre-processed by implementation of an appropriate bandpass finite-duration impulse response (FIR) filter and also by calculation of the Euclidean norm between corresponding samples of three leads. Then, a trous discrete wavelet transform (DWT) is applied to the resulted norm and an unscented synthetic measure is calculated between some obtained dyadic scales to magnify the effects of low-power waves such as P or T-waves during occurrence of arrhythmia(s). Afterwards, a uniform length window is slid sample to sample on the synthetic scale and in each slid, six features namely as summation of the nonlinearly amplified Hilbert transform, summation of absolute first order differentiation, summation of absolute second order differentiation, curve length, area and variance of the excerpted segment are calculated. Then all feature trends are normalized and superimposed to yield the newly defined multiple-order derivative wavelet based measure (MDWM) for the detection and delineation of ECG events. In the next step, a α-level Neyman-Pearson classifier (which is a false-alarm probability-FAP controlled tester) is implemented to detect and delineate QRS complexes. To show advantages of the presented method, it is applied to MIT-BIH Arrhythmia Database, QT Database, and T-Wave Alternans Database and as a result, the average values of sensitivity and positive predictivity Se = 99.96% and P+ = 99.96% are obtained for the detection of QRS complexes, with the average maximum delineation error of 5.7 msec, 3.8 msec and 6.1 msec for P-wave, QRS complex and T-wave, respectively showing marginal improvement of detection-delineation performance. In the next step, the proposed method is applied to DAY hospital high resolution holter data (more than 1,500,000 beats including Bundle Branch Blocks-BBB, Premature Ventricular Complex-PVC and Premature Atrial Complex-PAC) and average values of Se=99.98% and P+=99.97% are obtained for QRS detection. In summary, marginal performance improvement of ECG events detection-delineation process in a widespread values of signal to noise ratio (SNR), reliable robustness against strong noise, artifacts and probable severe arrhythmia(s) of high resolution holter data and the processing speed 163,000 samples/sec can be mentioned as important merits and capabilities of the proposed algorithm.
http://ijeee.iust.ac.ir/article-1-238-en.pdf
2013-12-30
1
18
ECG Detection-Delineation
First-Order Derivative
Second-Order Derivative
Discrete Wavelet Transform
Multi Lead Analysis
Hilbert Transform
Curve Length
Variance
Neyman-Pearson Hypothesis Test
False Alarm Probability
M. R.
Homaeinezhad
mrezahomaei@yahoo.com
1
AUTHOR
A.
Ghaffari
ghaffari@kntu.ac.ir
2
AUTHOR
H.
Najjaran Toosi
hamid.toosi@gmail.com
3
AUTHOR
M.
Tahmasebi
mrezahomaei@yahoo.com
4
AUTHOR
M. M.
Daevaeiha
m_davaeiha@yahoo.com
5
AUTHOR
OTHERS_CITABLE
Calculation of Stray Capacitances of MCG Coil include One Turn, Single-Layer and Conductor Wire Filaments in Rectangular form
This paper presents a new method called vespiary regular hexagonal (VRH) model in order to calculate parasitic capacitance between conductor wire filaments of one turn of coil (OTC) and between conductor wire filaments and liner and also total capacitance of one turn of the helix magneto flux cumulative generator (MCG) coil include single-layer conductor wire filaments in form of rectangular cross-section. In this paper, wire filaments of the coil are separated into many very small similar elementary cells. In this structure, an equilateral lozenge-shape basic cell (ELBC) with two trapezium-shape regions is considered between two adjacent conductor wire filaments in one turn of the generator coil. This method applies to calculate stray capacitance of one turn of the coil with multi conductor wire filaments (CWFs).
http://ijeee.iust.ac.ir/article-1-306-en.pdf
2013-12-30
19
27
Magneto Flux Cumulative Generator
Single-Layer
Stray Capacitance
Vespiary Model
M.
Mosleh
besmi@shahed.ac.ir
1
Shahed University
AUTHOR
M. R.
besmi
omidezati2000@yahoo.com
2
Shahed University
AUTHOR
OTHERS_CITABLE
Design Optimization for 4.1-THZ Quantum Cascade Lasers
We present an optimized design for GaAs/AlGaAs quantum cascade lasers operating at 4.1THz. This was based on a three-well active module with diagonal radiative transition. This was performed by modifying the existing model structure, to reduce the parasitic anticrossings (leakage currents) as well as the optical gain linewidth. While the gain FWHM was reduced by more than 50% the gain peak was increased by about 23.3%.
http://ijeee.iust.ac.ir/article-1-349-en.pdf
2013-12-30
28
32
Quantum Cascade Laser
Resonant Tunneling Transport
Parasitic Current Channel
M.
Moravvej-Farshi
farshi_k@modares.ac.ir
1
Tarbiat Modares University
AUTHOR
F.
Esmailifard
f_esmailifard@modares.ac.ir
2
Tarbiat Modares University
AUTHOR
K.
Saghafi
saghafi@shahed.ac.ir
3
Shahed University
AUTHOR
OTHERS_CITABLE
Improving Voltage Stability Margin Using Voltage Profile and Sensitivity Analysis by Neural Network
This paper presents a new approach for estimating and improving voltage stability margin from phase and magnitude profile of bus voltages using sensitivity analysis of Voltage Stability Assessment Neural Network (VSANN). Bus voltage profile contains useful information about system stability margin including the effect of load-generation, line outage and reactive power compensation so, it is adopted as input pattern for VSANN. In fact, VSANN establishes a functionality for VSM with respect to voltage profile. Sensitivity analysis of VSM with respect to voltage profile and reactive power compensation extracted from information stored in the weighting factor of VSANN, is the most dominant feature of the proposed approach. Sensitivity of VSM helps one to select most effective buses for reactive power compensation aimed enhancing VSM. The proposed approach has been applied on IEEE 39-bus test system which demonstrated applicability of the proposed approach.
http://ijeee.iust.ac.ir/article-1-281-en.pdf
2013-12-30
33
41
Voltage Stability Margin
Voltage Profile
Feature Extraction
Neural Networks
Sensitivity Analysis
M.
Aghamohammadi
Aghamohammadi@pwut.ac.ir
1
Assisstan Prof.
AUTHOR
S. S.
Hashemi
sina_hashemi_86@yahoo.com
2
AUTHOR
M. S.
Ghazizadeh
ghazizadeh@pwut.ac.ir
3
Assisstan Prof.
AUTHOR
OTHERS_CITABLE
Investigation and Control of Unstable Chaotic Behavior Using of Chaos Theory in Two Electrical Power Systems: 1-Buck Converter2- Power Transformer
This paper consist of two sections: control and stabilizing approach for chaotic behaviour of converter is introduced in first section of this paper for the removal of harmonic caused by the chaotic behaviour in current converter. For this work, a Time- Delayed Feedback Controller (TDFC) control method for stability chaotic behaviour of buck converter for switching courses in current control mode is presented. This behaviour is demonstrated by presenting a piecewise linear discrete map for this converter and then combining the feedback equation to obtain the overall equation of the converter. A simple time-delay feedback control method is applied to stabilize the Unstable Periodic Orbits (UPOs). In second section is studied the effect of a parallel metal oxide surge arrester on the ferroresonance oscillations of the transformer. It is expected that the arresters generally cause ferroresonance drop out. Simulation has been done on a three phase power transformer with one open phase. Effect of varying input voltage has been studied. The simulation results reveal that connecting the arrester to the transformer poles, exhibits a great mitigating effect on ferroresonant over voltages. Phase plane along with bifurcation diagrams are also presented. Significant effect on the onset of chaos, the range of parameter values that may lead to chaos and magnitude of ferroresonant voltages has been obtained, shown and tabulated.
http://ijeee.iust.ac.ir/article-1-352-en.pdf
2013-12-30
42
51
TDFC Method
Buck Converter
Fuzzy Diagram
Bifurcation Diagram
Power Transformer
Chaotic Ferroresonance
H.
Abbasi
hamid2005444@yahoo.com
1
iran university of science and technology
AUTHOR
A.
Gholami
hamidrezaabbasi1365@gmail.com
2
iran university of science and technology
AUTHOR
A.
Abbasi
ataollah_abbasi@yahoo.com
3
shahed university
AUTHOR
leghaallah@yahoo.com
4
AUTHOR
OTHERS_CITABLE
An Optimal Design Approach for Resistive and Inductive Superconducting Fault Current Limiters via MCDM Techniques
The design process of a superconducting current limiter (SFCL) requires simulation and definition of its electrical, magnetic and thermal properties in form of equivalent circuits and mathematical models. However, any change in SFCL parameters: dimension, resistance, and operating temperature can affect the limiting mode, quench time, and restore time. In this paper, following the simulation of electrical and thermal behavior of resistive and inductive SFCLs and investigation on their performance variation responded to change parameters, the best design cases will be selected by using multiple criteria decision making (MCDM) techniques. As a case study, to evaluate proposed MCDM approaches in design of superconducting fault current limiter, a model in which a SFCL is located at an outgoing feeder in a 20 kV distribution substation will be considered and best designs will be presented for both resistive and inductive type.
http://ijeee.iust.ac.ir/article-1-266-en.pdf
2013-12-30
52
59
Superconducting Fault Current Limiter
Multiple Criteria Decision Making
Analytic Hierarchy Process
H.
Heydari
heydari@iust.ac.ir
1
IUST
AUTHOR
R.
Sharifi
sharifi@ee.iust.ac.ir
2
IUST
AUTHOR
OTHERS_CITABLE
Controlling Both the DC Boost and AC Output Voltage of Z-Source Inverter Using Neural Network Controller with Minimization of Voltage Stress Across Devices
This paper presents a method to control both the dc boost and the ac output voltage of Z-source inverter using neural network controllers. The capacitor voltage of Z-source network has been controlled linearly in order to improve the transient response of the dc boost control of the Z-source inverter. The peak value of the line to line ac output voltage is used to control and keep the ac output at its desired value. A modified space vector pulse-width-modulation method is also applied to control the shoot-through duty ratio for boosting dc voltage. This modified method lets the dc voltage stress across the inverter switches be minimized. The neural network control technique is verified by simulation results. The results are compared with that of the traditional PI controller.
http://ijeee.iust.ac.ir/article-1-311-en.pdf
2013-12-30
60
69
Z-Source Inverter
Space Vector
Neural Network
D.
Arab Khaburi
khaburi@iust.ac.ir
1
Iran University Of Science and Technology
AUTHOR
H.
Rostami
rostami96@gmail.com
2
Iran University of Science and Technology
AUTHOR