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28,188 Article Results

Notice of Retraction Power Transformer Incipient Faults Diagnosis Based on Dissolved Gas Analysis

10.11591/ijeecs.v1.i1.pp10-16
Osama E. Gouda , Saber M. Saleh , Salah Hamdy El-hoshy
Notice of Retraction-----------------------------------------------------------------------After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IAES's Publication Principles.We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.The presenting author of this paper has the option to appeal this decision by contacting info@iaesjournal.com.-----------------------------------------------------------------------Incipient fault diagnosis of a power transformer is greatly influenced by the condition assessment of its insulation system oil and/or paper insulation. Dissolved gas-in-oil analysis (DGA) is one of the most powerfull techniques for the detection of incipient fault condition within oil-immersed transformers. The transformer data has been analyzed using key gases, Doernenburg, Roger, IEC and Duval triangle techniques. This paper introduce a MATLAB program to help in unification DGA interpretation techniques to investigate the accuracy of these techniques in interpreting the transformer condition and to provide the best suggestion for the type of the fault within the transformer based on fault percentage. It proposes a proper maintenance action based on DGA results which is useful for planning an appropriate maintenance strategy to keep the power transformer in acceptable condition. The evaluation is carried out on DGA data obtained from 352 oil samples has been summarized  into 46 samples that have been collected from a 38 different transformers of different rating and different life span.
Volume: 1
Issue: 1
Page: 10-16
Publish at: 2016-01-01

On the Impact of Timer Resolution in the Efficiency Optimization of Synchronous Buck Converters

10.11591/ijpeds.v6.i4.pp693-702
Pedro Amaral , Cândido Duarte , Pedro Costa
Excessive dead time in complementary switches causes significant energy losses in DC-DC power conversion. The optimization of dead time prevents the degradation of overall efficiency by minimizing the body diode conduction of power switches and, as a consequence, also reduces reverse recovery losses. The present work aims at analyzing the influence of one of the most important characteristics of a digital controller, the timer resolution, in the context of dead-time optimization for synchronous buck converters. In specific, the analysis quantifies the efficiency de-pendency on the timer resolution, in a parameter set that comprises duty-cycle and dead-time, and also converter frequency and analog-to-digital converter accuracy. Based on a sensorless optimization strategy, the relationship between all these limiting factors is described, such as the number of bits of timer and analog-to-digital converter. To validate our approach experimental results are provided using a 12-to-1.8V DC-DC converter, controlled by low- and high-resolution pulse-width modulation signals generated with an XMC4200 microcontroller from Infineon Technologies. The measured results are consistent with our analysis, which predicts the power efficiency improvements not only with a fixed dead time approach, but also with the increment of timer resolution.
Volume: 6
Issue: 4
Page: 693-702
Publish at: 2015-12-01

Performance Measurement of a Compact Generator - Hydro Turbine System

10.11591/ijece.v5i6.pp1252-1261
Pudji Irasari , Priyono Sutikno , Puji Widiyanto , Qidun Maulana
This study aims to investigate the characteristic of a compact generator – hydro turbine system. The generator is of permanent magnet type and the turbine operates in a very low head. The integration of the two components is conducted in such a way that simplifies the construction of the conventional turbine generator. The method is by mounting the generator stator to the turbine casing and the permanent magnets are assembled in the perimeter of the turbine blade rotor. This simple construction is approached by making the stator from individual teeth and yoke. The permanent magnet generator (PMG) is designed to produce the nominal power of 300 Watt 50 Hz at 83 rpm of turbine shaft. All components of the integrated turbine- generator are totally immersed in the water stream. The stator has to be hermitic to avoid water entering the spool. Another issue investigated is the influence of the type of the stator inner casing material to the generator performance. The results show, the PVC material for inner casing has a good influence to the generator performance compared with the mild steel material.
Volume: 5
Issue: 6
Page: 1252-1261
Publish at: 2015-12-01

Ohmic Contact characterization Using Image Processing

10.11591/ijece.v5i6.pp1347-1353
Shashikala B.N. , Nagabhushana B.S.
The Ti/Al/Ni/Au films deposited by electron beam evaporation on n type GaN was demonstrated as a suitable solution for low resistive and thermally stable contact to n-type GaN. The surface morphology of Ti/Al/Ni/Au and Ti/Al contacts were studied as a function of the annealing process conditions using image processing techniques. The algorithm was implemented using the MATLAB software. Using the algorithm made, the area occupied by the pores and porosity in the ohmic contact structures were obtained.
Volume: 5
Issue: 6
Page: 1347-1353
Publish at: 2015-12-01

Dynamic Time Slice Calculation for Round Robin Process Scheduling Using NOC

10.11591/ijece.v5i6.pp1480-1485
G Siva Nageswara Rao , N. Srinivasu , S.V.N. Srinivasu , G. Rama Koteswara Rao
Process scheduling means allocating a certain amount of CPU time to each of the user processes.  One of the popular scheduling algorithms is the “Round Robin” algorithm, which allows each and every process to utilize the CPU for short time duration.  Processes which finish executing during the time slice are removed from the ready queue.  Processes which do not complete execution during the specified time slice are removed from the front of the queue, and placed at the rear end of the queue. This paper presents an improvisation to the traditional round robin scheduling algorithm, by proposing a new method. The new method represents the time slice as a function of the burst time of the waiting process in the ready queue. Fixing the time slice for a process is a crucial factor, because it subsequently influences many performance parameters like turnaround time, waiting time, response time and the frequency of context switches.  Though the time slot is fixed for each process, this paper explores the fine-tuning of the time slice for processes which do not complete in the stipulated time allotted to them.
Volume: 5
Issue: 6
Page: 1480-1485
Publish at: 2015-12-01

Comparing Performance of Data Mining Algorithms in Prediction Heart Diseases

10.11591/ijece.v5i6.pp1569-1576
Moloud Abdar , Sharareh R. Niakan Kalhori , Tole Sutikno , Imam Much Ibnu Subroto , Goli Arji
Heart diseases are among the nation’s leading couse of mortality and moribidity. Data mining teqniques can predict the likelihood of patients getting a heart disease. The purpose of this study is comparison of different data mining algorithm on prediction of heart diseases. This work applied and compared data mining techniques to predict the risk of heart diseases. After feature analysis, models by five algorithms including decision tree (C5.0), neural network, support vector machine (SVM), logistic regression and k-nearest neighborhood (KNN) were developed and validated. C5.0 Decision tree has been able to build a model with greatest accuracy 93.02%, KNN, SVM, Neural network have been 88.37%, 86.05% and 80.23% respectively. Produced results of decision tree can be simply interpretable and applicable; their rules can be understood easily by different clinical practitioner.
Volume: 5
Issue: 6
Page: 1569-1576
Publish at: 2015-12-01

Electromagnetic Performance due to Tooth-tip Design in Fractional-slot PM Brushless Machines

10.11591/ijpeds.v6.i4.pp860-868
Mohd Luqman Mohd Jamil , Zulfikri Zaki Zolkapli , Auzani Jidin , Raja Nor Firdaus Raja Othman , Tole Sutikno
Permanent Magnet (PM) machines are favorable as an alternative to other machine topologies due to simpler construction and high torque density. However, it may result hight torque ripple due to an influence of cogging torque and electronic commutation. In this paper, comparisons of phase back-emf, static torque and cogging torque due to influence of tooth-tip asymmetry in 12-slot/10-pole double-layer and 12-slot/10-pole single layer winding machines are carried out using 2D Finite-Element Analysis. At rated condition, the stator asymmetry has great influence on the torque performance as there is significant reduction of torque ripple in 12-slot/10-pole mahine equipped with single layer winding than one equipped with double layer winding machine. It si confirmed that an optimum torque performance is desirable via stator iron modification in PM machines.
Volume: 6
Issue: 4
Page: 860-868
Publish at: 2015-12-01

A Novel Power Factor Correction Rectifier for Enhancing Power Quality

10.11591/ijpeds.v6.i4.pp772-780
Bindu K V , B Justus Rabi
In this paper, the disturbances in power system due to low quality of power are discussed and a current injection method to maintain the sinusoidal input current which will reduce the total current harmonic distortion (THD) as well as improve the power factor nearer to unity is proposed. The proposed method makes use of a novel controlled diode rectifier which involves the use of bidirectional switches across the front-end rectifier and the operation of the converter is fully analyzed. The main feature of the topology is low cost, small size, high efficiency and simplicity, and is excellent for retrofitting front-end rectifier of existing ac drives, UPS etc. A novel strategy implementing reference compensation current depending on the load harmonics and a control algorithm for three-phase three-level unity PF rectifier which draws high quality sinusoidal supply currents and maintains good dc link- voltage regulation under wide load variation. The proposed technique can be applied as a retrofit to a variety of existing thyristor converters which uses three bidirectional switches operating at low frequency and a half-bridge inverter operating at high frequency .The total power delivered to the load is processed by the injection network, the proposed converter offers high efficiency and not only high power factor but also the Total Harmonic Distortion is reduced. Theoretical analysis is verified by digital simulation and a hardware proto type module is implemented in order to confirm the feasibility of the proposed system. This scheme in general is suitable for the common variable medium-to high-power level DC load applications.
Volume: 6
Issue: 4
Page: 772-780
Publish at: 2015-12-01

Development of Predictive Current Controller for Multi-Port DC/DC Converter

10.11591/ijpeds.v6.i4.pp683-692
Santhosh T K , Govindaraju C
This paper investigates the utilization of a predictive current control for a fourport DC/DC power electronic converter with an input port, two storage portsand a load port suitable for a Hybrid Electric Vehicle. Being a power converterwith multiple ports, it has different operating modes. While the Stateflow con-troller is employed to handle mode selection, the predictive current controller isemployed for the inductor current control. The control laws governing each op-erating mode is derived out for valley current control. By making the inductorcurrent in the upcoming switching cycle equivalent to the reference, the duty cycleis predicted. Simulation and experimental results show improvements in currentripple minimization, faster dynamic performance and comparable to traditionalcontrol method.
Volume: 6
Issue: 4
Page: 683-692
Publish at: 2015-12-01

Effect of Height of the Substrate and Width of the Patch on the Performance Characteristics of Microstrip Antenna

10.11591/ijece.v5i6.pp1441-1445
R. Mishra , P. Kuchhal , A. Kumar
The demand for broad-band antennas has been increased in the recent years. They find to be extensively used in high frequency and high speed data communication. The factors affecting the bandwidth of the microstrip antenna is discussed in this paper. There are two main parameter responsible for the broadening of the antenna. One is the height of the dielectric substrate and another one is the width of the patch.  In this paper, we study the performance characteristics of rectangular patch antenna with variable thickness of the substrate and width of the patch. One of the parameter is varied keeping the other fixed and the characteristic effects on resonant frequency, band width and gain are studied.
Volume: 5
Issue: 6
Page: 1441-1445
Publish at: 2015-12-01

Clutter Reduction in Parallel Coordinates using Binning Approach for Improved Visualization

10.11591/ijece.v5i6.pp1564-1568
Swathy Sunil Kumar , Teenu Krishnan , Sreeja Ashok , M.V. Judy
As the data and number of information sources keeps on mounting, the mining of necessary information and their presentation in a human delicate form becomes a great challenge. Visualization helps us to pictorially represent, evaluate and uncover the knowledge from the data under consideration. Data visualization offers its immense opportunity in the fields of trade, banking, finance, insurance, energy etc. With the data explosion in various fields, there is a large importance for visualization techniques. But when the quantity of data becomes elevated, the visualization methods may take away the competency. Parallel coordinates is an eminent and often used method for data visualization. However the efficiency of this method will be abridged if there are large amount of instances in the dataset, thereby making the visualization clumsier and the data retrieval very inefficient. Here we introduced a data summarization approach as a preprocessing step to the existing parallel coordinate method to make the visualization more proficient.
Volume: 5
Issue: 6
Page: 1564-1568
Publish at: 2015-12-01

Implementation of Space Vector Modulator for Cascaded H-Bridge Multilevel Inverters

10.11591/ijpeds.v6.i4.pp906-918
Syamim Sanusi , Auzani Jidin , Tole Sutikno , Kasrul Abdul Karim , Mohd Luqman Jamil , Siti Azura Ahmad Tarusan
The Space Vector Modulation (SVM) technique has gained wide acceptance for many AC drive applications, due to a higher DC bus voltage utilization (higher output voltage when compared with the SPWM), lower harmonic distortions and easy digital realization. In recent years, the SVM technique was extensively adopted in multilevel inverters since it offers greater numbers of switching vectors for obtaining further improvements of AC drive performances. However, the use of multilevel inverters associated with SVM increases the complexity of control algorithm (or computational burden), in obtaining proper switching sequences and vectors. The complexity of SVM computation causes a microcontroller or digital signal processor (DSP) to execute the computation at a larger sampling time. This consequently may produce errors in computation and hence degrades the control performances of AC motor drives. This paper presents a developement of SVM modulator for three-level Cascaded H-Bridge Multilevel Inverter (CHMI) using a hybrid controller approach, i.e. with combination between the DS1104 Controller Board and FPGA. In such way, the computational burden can be minimized as the SVM tasks are distributed into two parts, in which every part is executed by a single controller. This allows the generation of switching gates performed by FPGA at the minimum sampling time 〖DT〗_2=540 ns to obtain precise desired output voltages, as can be verified via simulation and experimental results.
Volume: 6
Issue: 4
Page: 906-918
Publish at: 2015-12-01

Resource Sharing in Libraries on Cloud Landscape: Potentials and Paradoxes

10.11591/ijict.v4i3.pp98-110
Mayank Yuvaraj
The initial hype of any development can eclipse its practical applications. The present paper attempts to separate the hype of cloud computing and explores the possibilities of resource sharing in libraries through Cloud Computing. The present study is based on the usage pattern of cloud computing in libraries and explores a model for resource sharing. It also proposes a cloud based resource sharing framework for moving from ground to the cloud. Although a lot of work has been done on cloud computing yet none of the works has been dedicated to the cause of libraries. With the development of electronic resources and shift in user’s preference of online services there is an urgent need of change in library practices.
Volume: 4
Issue: 3
Page: 98-110
Publish at: 2015-12-01

EASR: Graph-based Framework for Energy Efficient Smart Routing in MANET using Availability Zones

10.11591/ijece.v5i6.pp1381-1395
Ramanna Havinal , Girish V Attimarad , M N Giriprasad
Energy consumption in MobileAdhoc Network (MANET) is a topic of research from more than a decade. Althoughthere are multiple archival of literatures, that have proposed variousenergy-efficient algorithms for reducing the energy consumption to improveenergy efficiency. Establishing correct and reliable route is important designissue in MANET, but a more challenging goal is to provide energy efficientroute. But, it was observed that majority of such energy efficient routingprotocols just give symptomatic solution which addresses and mitigated theenergy issues overlooking various associated issues like quality of services.Moreover, in majority of research previous studies it is found that AODV andDSDV are highly in adoption rate among the researcher for solving energy issuesusing routing protocols. This manuscript after reviewing some of thesignificant literatures in past explored issues in existing AODV and DSDVand  proposes a novel energy efficientrouting protocols by incorporating a new actor called availability zone. Theproposed model shows better energy efficiency and QoS compared to AODV andDSDV.
Volume: 5
Issue: 6
Page: 1381-1395
Publish at: 2015-12-01

Anti-Phishing Techniques in Cryptography

10.11591/ijece.v5i6.pp1511-1515
Akshey Nanda , Himanshu Gupta
Phishing is a process in which Phishers try to leak out the credentials of users by hosting a fake web page on user's browser. To save users from phishing attacks, many researchers have dug deep and presented their insights. Nowadays, in the era of 21st century,  banks are using the OTP and visual cryptography for the authentication of both sides i.e. user and the bank. In this paper, we are proposing a methodology in which a user will need to give his finger prints as an authentication.
Volume: 5
Issue: 6
Page: 1511-1515
Publish at: 2015-12-01
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