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27,404 Article Results

Application of Coupled Inductors for Reducing Switching Stresses in a Hybrid Power System

10.11591/ijeecs.v16.i3.pp463-472
Dharani M , Usha P
This paper presents a novel methodology using coupled inductor for hybridizing multi input sources. A four port three input dc-dc converter is chosen, two photovoltaic sources and a storage medium are interfaced with the converter. The two sources can supply the load as well as charge the battery. Four independently controlled switches are employed to provide dc regulated output. The hybridization of the sources and converter is achieved by coupled inductors. The results show that the presence of coupled inductors increases the voltage gain and reduces the switching stress. The proposed system is verified and validated in MATLAB environment under various operating condition.
Volume: 16
Issue: 3
Page: 463-472
Publish at: 2015-12-01

An Optimistic Approach for Clustering Multi-version XML Documents Using Compressed Delta

10.11591/ijece.v5i6.pp1472-1479
Vijay R Sonawane , D. Rajeswara Rao
Today with Standardization of XML as an information exchange over web, huge amount of information is formatted in the XML document. XML documents are huge in size. The amount of information that has to be transmitted, processed, stored, and queried is often larger than that of other data formats. Also in real world applications XML documents are dynamic in nature. The versatile applicability of XML documents in different fields of information maintenance and management is increasing the demand to store different versions of XML documents with time. However, storage of all versions of an XML document may introduce the redundancy. Self describing nature of XML creates the problem of verbosity,in result documents are in huge size. This paper proposes optimistic approach to Re-cluster multi-version XML documents which change in time by reassessing distance between them by using knowledge from initial clustering solution and changes stored in compressed delta. Evolving size of XML document is reduced by applying homomorphic compression before clustering them which retains its original structure. Compressed delta stores the changes responsible for document versions, without decompressing them. Test results shows that our approach performs much better than using full pair-wise document comparison.
Volume: 5
Issue: 6
Page: 1472-1479
Publish at: 2015-12-01

The Dynamic of Synchronous Generator under Unbalanced Steady State Operation: A Case of Virtual Generator Laboratory

10.11591/ijece.v5i6.pp1292-1303
Sugiarto Kadiman , Arif Basuki , Mytha Arena
The purpose of this study is to design and develop a synchronous generator virtual laboratory for undergraduate student courses, which can be treated as an accessorial tool for enhancing instruction. Firstly, the study reviews the general concept and algorithm of synchronous generator model. Secondly, the simulation method of this system is discussed. Finally, the paper introduces its example and analysis. One of the major objectives of this project is the dynamics of synchronous generators connected to the 500 kV EHV Jamali (Jawa-Madura-Bali) System under unbalanced steady state condition that could be modeled as a balanced synchronous generator’s model with unbalanced voltage inputs. The balanced synchronous generator model based on the rotor’s qd0 reference frame was chosen to substitute generator’s model embeded in loadflow analysis. The verification of the proposed generator’s model was checked by comparing it with a PSS Tecquiment NE9070 simulator. The unbalanced voltage inputs of generator were derived utilizing the loadflow analysis by determining the phase and sequence currents, and average bus voltages of the 500 kV EHV Jamali grid considering unbalanced portion variations. Meanwhile, the load locations having significant effect on the test generators are obtained by using the electricity tracing method. The developed virtual laboratory with a given example demonstrated the usefulness of the tool for studying synchronous generator under unbalanced steady-state operation.
Volume: 5
Issue: 6
Page: 1292-1303
Publish at: 2015-12-01

Compact Integrated Bluetooth UWB Antenna with Quadruple Bandnotched Characteristics

10.11591/ijece.v5i6.pp1433-1440
Rekha P Labade , Shankar B Deosarkar , Narayan Pisharoty
In this paper,a compact printed dualband antenna for Bluetooth and UWB applications with WiMax(3.3-3.7 GHz), C-band satellite downlink(3.7-4.2GHz), WLAN(5.15-5.825GHz) and DSRC(5.5-5.925GHz) bandnotched characteristics is proposed and investigated. By etching two half-wavelength L-shaped slots in the radiating patch and an inverted U-shaped slot in the microstrip feedline quadruple bandnotched characteristics is obtained. Further, by embedding quarter wavelength parasitic strip at two edges of U-shaped radiating patch dualband characteristics with desired bandwidth is obtained. the proposed antenna is designed and fabricated on a FR4 substrate of dimensions 24mm X 35mm that operates over a 2.4-11GHz with S11<-10dB except over notch bands of 3.3-3.7GHz, 3.7-4.2GHz,5.15-5.625GHz and 5.625-6GHz. Directional pattern in E-plane and nearly omnidirectional pattern in H-plane are observed over a UWB band except at desired bandnotched freqencies. Less variation in group delay and pulse deformation shows good time domain characteristics. In addition, the structure exhibits stable gain over the desired band.
Volume: 5
Issue: 6
Page: 1433-1440
Publish at: 2015-12-01

Recommender Systems in Light of Big Data

10.11591/ijece.v5i6.pp1553-1563
Khadija A. Almohsen , Huda Al-Jobori
The growth in the usage of the web, especially e-commerce website, has led to the development of recommender system (RS) which aims in personalizing the web content for each user and reducing the cognitive load of information on the user. However, as the world enters Big Data era and lives through the contemporary data explosion, the main goal of a RS becomes to provide millions of high quality recommendations in few seconds for the increasing number of users and items. One of the successful techniques of RSs is collaborative filtering (CF) which makes recommendations for users based on what other like-mind users had preferred. Despite its success, CF is facing some challenges posed by Big Data, such as: scalability, sparsity and cold start. As a consequence, new approaches of CF that overcome the existing problems have been studied such as Singular value decomposition (SVD). This paper surveys the literature of RSs and reviews the current state of RSs with the main concerns surrounding them due to Big Data. Furthermore, it investigates thoroughly SVD, one of the promising approaches expected to perform well in tackling Big Data challenges, and provides an implementation to it using some of the successful Big Data tools (i.e. Apache Hadoop and Spark). This implementation is intended to validate the applicability of, existing contributions to the field of, SVD-based RSs as well as validated the effectiveness of Hadoop and spark in developing large-scale systems. The implementation has been evaluated empirically by measuring mean absolute error which gave comparable results with other experiments conducted, previously by other researchers, on a relatively smaller data set and non-distributed environment. This proved the scalability of SVD-based RS and its applicability to Big Data.
Volume: 5
Issue: 6
Page: 1553-1563
Publish at: 2015-12-01

Performance of Fractional-Slot Winding PM Machines due to Un-even Coil Turns and Asymmetric Design of Stator Teeth

10.11591/ijpeds.v6.i4.pp853-859
Mohd Luqman Mohd Jamil , Syed Muhammad S. A. Al-Habshi , Md Nazri Othman , Tole Sutikno
PM machines in which slot number and pole number combination differs by one have to be configured with asymmetric winding pattern in order to maximize it back-emf performance. However, this asymmetric winding configuration inherently results an unwanted Unabalanced Magnetic Force (UMF). Investigations of electromagnetic performance of fractional-slot asymmetric winding PM machines using 2-D Finite-Element Analysis are presented. The investigations are mainly driven by the effort of minimizing the UMF. By employing techniques such as non-uniform number of coil turns in every tooth and asymmetric design of stator tooth, the UMF are expected can be minimized. The investigations show that the radial component of UMF has greater effect than the tangential component on the UMF itself. In all proposed techniques, a slight reduction of machine torque performance is inevitable.
Volume: 6
Issue: 4
Page: 853-859
Publish at: 2015-12-01

The Camparison of Harmonic Distortion Self-Excited Induction Generator with Isolated Synchronous Generator under Non-linear Loads

10.11591/ijpeds.v6.i4.pp759-771
Refdinal Nazir , Krismadinata Krismadinata , Rizka Amalia
In this paper, the harmonic distortion for Self-Excited Induction Generator (SEIG) and an isolated synchronous generator (ISG) under non-linear load during steady state conditions are analyzed. The voltage and current harmonics distortion for both generators are calculated using the transfer function method in frequency domain for SEIG and phasor diagram method for ISG. This analysis is done independently one by one component for all harmonic components appear. The analysis results for both generators are verified to the laboratory test results. For loading with the same non-linear load to both generators, the harmonics distortion on the stator windings of SEIG was smaller than compare ISG. In addition, the harmonic distortion effects on other loads connected to PCC point of SEIG was lower than the other loads connected to ISG.
Volume: 6
Issue: 4
Page: 759-771
Publish at: 2015-12-01

Sociopsychotechnological Predictors of Individual’s Social Loafing in Virtual Team

10.11591/ijece.v5i6.pp1500-1510
Juneman Abraham , Melina Trimutiasari
The rapid development of technology and the demands of the workers to be productive have made efficiency and effectiveness of virtual team collaboration is becoming increasingly urgent lately. Therefore, it is important to identify the variables undermining the efficiency and effectiveness. This study aimed to investigate the role of perceived usefulness, perceived ease of use, and perceived playfulness of online collaboration tool (as elements of technology acceptance) and xenophobia in predicting social loafing (at the individual level)─a social psychological phenomenon that shows the declining performance of the individual when working in the group. The contribution of this research is its attempt to combine social psychological and technological factors in explaining human performance in the context of the group when interacting with technology. The research design was correlational predictive, with multiple linear regression data analysis technique. Participants of this study were 80 students and employees (43 males, 37 females; mean of age = 25.58 years of old, standard deviation of age = 4.92 years) who work using online collaboration tool in a virtual team. The results showed that the perceived playfulness, perceived ease of use, and xenophobia were able to predict an individual’s social loafing, but the perceived usefulness is not able to predict it. Implications of the results of research in order to prevent social loafing are stated in the Discussion section.
Volume: 5
Issue: 6
Page: 1500-1510
Publish at: 2015-12-01

Co-Simulation Interfacing Capabilities in Device-Level Power Electronic Circuit Simulation Tools: An Overview

10.11591/ijpeds.v6.i4.pp665-682
Wentao Wang , Wenying Yang , Venkata Dinavahi
Power electronic circuit simulation today has become increasingly more demanding in both the speed and accuracy. Whilst almost every simulator has its own advantages and disadvantages, co-simulations are becoming more prevalent. This paper provides an overview of the co-simulation capabilities of device-level circuit simulators. More specifically, a listing of device-level simulators with their salient features are compared and contrasted. The co-simulation interfaces between several simulation tools are discussed. A case study is presented to demonstrate the co-simulation between a device-level simulator (PSIM) interfacing a system-level simulator (Simulink), and a finite element simulation tool (FLUX). Results demonstrate the necessity and convenience as well as the drawbacks of such a comprehensive simulation.
Volume: 6
Issue: 4
Page: 665-682
Publish at: 2015-12-01

Evaluation of PV, Wind, Diesel Hybrid Energy Potential for GSM Tower in Myanmar

10.11591/ijece.v5i6.pp1245-1251
Zin Mar Nyo
Not only GSM, WCDMA but also CDMA technology can be used in Myanmar but GSM pre-dominates in the market. There are over million unique subscribers across the country in 2013. Power supply for telecom becomes main challenges in Myanmar where the electricity can not access in rural area. To minimize deficit of power, the government has set a target to covert some of tower sites to renewable solutions by 2015. This paper proposes the use of a PV, wind and diesel generator hybrid system with storage element in order to determine the optimal configuration of renewable energy in Myanmar.  This paper discusses the development of a renewable energy sources (RES)  that  can  be  used  for  electric  power  supply  of  GSM  base  station  site  at  any  given  time and  considers  the  feasibility  of  developing  Solar  (photovoltaic)-Wind-Diesel  hybrid power  systems  for  supplying  electricity  to  off-grid  rural telecommunication.  The Hybrid Optimization Model for Electric Renewables (HOMER) was used  to  simulate  and  generate  feasible  solution  through  combinations of photovoltaic, Wind Turbines and Diesel  Generator with  a  minimum  levelised  cost  of  electricity supply and to  determine  the  technical feasibility of the system.
Volume: 5
Issue: 6
Page: 1245-1251
Publish at: 2015-12-01

Metamaterial Inspired Patch Antenna for ISM Band by Adding Single-Layer Complementary Split Ring Resonators

10.11591/ijece.v5i6.pp1328-1335
Rajni Rajni , Gursharan Kaur , Anupma Marwaha
In this work, we propose the design of metamaterial inspired compact circular patch antennas loaded with complementary split-ring resonators (CSRRs) for ISM band operation. CSRRs have been incorporated horizontally inside the dielectric. The various models of CSRR loaded antennas with different patch radius are produced and are evaluated numerically with Ansoft HFSS software. The results of the suggested antenna designs are presented that reveal a comparable impedance match and radiation characteristics with those of a normal patch antenna without CSRR. The proposed antennas yield high levels of miniaturization and similar performance to the conventional patch antenna at the 2.45GHz.
Volume: 5
Issue: 6
Page: 1328-1335
Publish at: 2015-12-01

Ontologies and Bigram-based approach for Isolated Non-word Errors Correction in OCR System

10.11591/ijece.v5i6.pp1458-1467
Aicha Eutamene , Mohamed Khireddine Kholladi , Hacene Belhadef
In this paper, we describe a new and original approach for post-processing step in an OCR system. This approach is based on new method of spelling correction to correct automatically misspelled words resulting from a character recognition step of scanned documents by combining both ontologies and bigram code in order to create a robust system able to solve automatically the anomalies of classical approaches. The proposed approach is based on a hybrid method which is spread over two stages, first one is character recognition by using the ontological model and the second one is word recognition based on spelling correction approach based on bigram codification for detection and correction of errors. The spelling error is broadly classified in two categories namely non-word error and real-word error. In this paper, we interested only on detection and correction of non-word errors because this is the only type of errors treated by an OCR. In addition, the use of an online external resource such as WordNet proves necessary to improve its performances.
Volume: 5
Issue: 6
Page: 1458-1467
Publish at: 2015-12-01

Modified Synchronous Reference Frame Based Harmonic Extraction for Shunt Active Filter

10.11591/ijpeds.v6.i4.pp897-905
C.S. Subash Kumar , V. Gopalakrishnan
This paper presents the modified synchronous reference frame based Shunt Active Filter (SAF) for the instantaneous compensation of harmonic current present at the Point of Common Coupling. The harmonics generated by the non linear load are extracted using the positive frame and negative frame of the input signal using the modified synchronous reference frame theory with extended Multiple Reference Frame based PLL (EMRFPLL). Based on the harmonics extracted, pulse width modulation signals are generated using Artificial Neural Network based Space Vector Pulse width Modulation technique (ANNSVPWM). Using this switching technique the losses can be reduced and compensation can be done more accurately The concept was verified using MATLAB / Simulink Simulation and the results confirm the THD at point of common coupling is below the required standards.
Volume: 6
Issue: 4
Page: 897-905
Publish at: 2015-12-01

Low Voltage Ride-through Capability Enhancement of Doubly Fed Induction Generator Based Wind Turbines under Voltage Dips

10.11591/ijpeds.v6.i4.pp808-818
Youness Boukhris , Aboubakr El Makrini , Hassan El Moussaoui , Hassane El Markhi
Based on the advantages of doubly fed induction generator (DFIG)-based wind turbine (WT). This paper proposes a new control strategy to improve the ride-through capability of DFIG-based WTs in the event of a grid fault. The proposed method is performed by using the DFIG converters control and the addition of the damping resistances connected to the DC circuit, to follow the requirements defined by the grid codes. The proposed ride-through solution limits the peak values of the DC link voltage, the rotor inrush current, electromagnetic torque and DFIG transient response at the times of occurrence and clearing the fault. The proposed solution is simulated and compared with the crowbar solution using MATLAB/Simulink environment.
Volume: 6
Issue: 4
Page: 808-818
Publish at: 2015-12-01

A Novel Method for Vector Control of Faulty Three-Phase IM Drives Based on FOC Method

10.11591/ijece.v5i6.pp1284-1291
Mohammad Jannati , Nik Rumzi Nik Idris , Mohd Junaidi Abdul Aziz , Tole Sutikno
This paper proposes a novel method for vector control of faulty three-phase Induction Motor (IM) drives based on Field-Oriented Control (FOC) method. The performance characteristics of the presented drive system are investigated at healthy and open-phase fault conditions. The simulation of the case study is carried out by using the Matlab/M-File software for a star-connected three-phase IM. The results show the better performance of the proposed drive system especially in reduction of motor speed and torque oscillations during open-phase fault operating.
Volume: 5
Issue: 6
Page: 1284-1291
Publish at: 2015-12-01
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