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27,762 Article Results

Research Designs and Methods in Self-assessment Studies: A Content Analysis

10.11591/ijere.v6i4.8921
Serafina Pastore
This paper focuses on self-assessment practices in the higher education field. In the assessment for learning perspective, self-assessment is related to reflection, metacognition, and self-regulation: all these aspects are considered as fundamental prerequisites for students’ future professional development. Despite the recognition of self-assessment educational benefits and implications, research so far lags behind the rise in the rates of align literature review, research design, and methodology. The study attempts to address this gap in the literature. Based on a critical review of institutional changes in the European higher education context, the paper reflected on main issues and problems faced by educational research on self-assessment. It then tried to identify future research pathways on this topic.
Volume: 6
Issue: 4
Page: 257-264
Publish at: 2017-12-01

Evaluating Aggregate Functions of Iceberg Query Using Priority Based Bitmap Indexing Strategy

10.11591/ijece.v7i6.pp3745-3752
Kale Sarika Prakash , P.M. Joe Prathap
Aggregate function and iceberg queries are important and common in many applications of data warehouse because users are generally interested in looking for variance or unusual patterns. Normally, the nature of the queries to be executed on data warehouse are the queries with aggregate function followed by having clause, these type of queries are known as iceberg query. Especially to have efficient techniques for processing aggregate function of iceberg query is very important because their processing cost is much higher than that of the other basic relational operations such as SELECT and PROJECT. Presently available iceberg query processing techniques faces the problem of empty bitwise AND,OR  XOR operation and requires more I/O access and time.To overcome these problems proposed research provides efficient algorithm to execute iceberg queries using priority based bitmap indexing strategy. Priority based approach consider  bitmap vector to be executed as per the priority.Intermediate results are evaluated to find probability of result.Fruitless operations are identified and skipped in advance which help to reduce I/O access and time.Time and iteration required to process query is reduced [45-50] % compare to previous strategy.  Experimental result proves the superiority of priorty based approach compare to previous bitmap processing approach.
Volume: 7
Issue: 6
Page: 3745-3752
Publish at: 2017-12-01

Implementation of Cloud Connected Smart Robot for Environmental and Industrial Platform

10.11591/ijeecs.v8.i3.pp645-647
Senthil Kumar M. , V. Mathivanan
Cloud robotics is an emerging field that is centred on the benefits of converged infrastructure and shared services of a cloud computing environment. In this paper, a system is designed with an autonomous Pick and Place robot to sense environmental data such as temperature and Motion, along with GPS coordinates and sends them on the cloud. The mobile robot is controlled using an LPC1764 microcontroller and communicates with the cloud via a CC3200 Launchpad. A private cloud is set up using Open Stack that provides Infrastructure as a Service. The collected data are stored in a cloud server which could be viewed through a mobile app and can be used to create awareness about the environmental changes of the location under study. A proof-of-concept prototype has been developed to illustrate the effectiveness of the proposed system.
Volume: 8
Issue: 3
Page: 645-647
Publish at: 2017-12-01

Performance Analysis of 12Slot with Various Rotor Pole Numbers HE-FSM for HEV Application

10.11591/ijpeds.v8.i4.pp1886-1893
Siti Khalidah Rahimi , Zarafi Ahmad , Erwan Sulaiman , Enwelum Mbadiwe I , Syed Muhammad Naufal Syed Othman
This paper presents performance analysis of 12Slot with various rotor pole numbers Hybrid Excitation Flux Switching Machine (HEFSM) for Hybrid Electric Vehicles (HEVs) application. HEFSM has carried out by combining the advantage of Permanent Magnet (PM) machines and DC Field Excitation Coil (FEC) synchronous machines. Previously, most of HEFSM structure having FEC windings in theta direction that create a problem of flux cancellation that will affect the performances of the machine.  Thus, a design of 12Slot HEFSM with FEC wounded in radial direction is proposed to eliminate the flux cancellation effect.  At first, armature coil arrangement test at no-load condition is conducted to analyze PM flux. Furthermore, induced voltage and cogging torque at open circuit condition are investigated based on 2D finite element analysis (FEA). Finally, torque and power performances are also examined at maximum FEC and armature current densities. The outcomes demonstrate that 12S-14P configuration has the highest PM flux linkage, torque, power and less distortion of back-emf waveform which are required to be used as a motor in HEVs. The highest torque and power achieved are 220.15Nm and 92.45kW, respectively.
Volume: 8
Issue: 4
Page: 1886-1893
Publish at: 2017-12-01

Maximizing Energy Efficiency for Consumption Circuit Power in Downlink Massive MIMO Wireless Networks

10.11591/ijece.v7i6.pp2977-2985
Adeeb Salh , Lukman Audah , Nor Shahida M. Shah , Shipun A. Hamzah
Massive multi-input–multi-output (MIMO) systems are crucial to maximizing energy efficiency (EE) and battery-saving technology. Achieving EE without sacrificing the quality of service (QoS) is increasingly important for mobile devices. We first derive the data rate through zero forcing (ZF) and three linear precodings: maximum ratio transmission (MRT), zero forcing (ZF), and minimum mean square error (MMSE). Performance EE can be achieved when all available antennas are used and when taking account of the consumption circuit power ignored because of high transmit power. The aim of this work is to demonstrate how to obtain maximum EE while minimizing power consumed, which achieves a high data rate by deriving the optimal number of antennas in the downlink massive MIMO system. This system includes not only the transmitted power but also the fundamental operation circuit power at the transmitter signal. Maximized EE depends on the optimal number of antennas and determines the number of active users that should be scheduled in each cell. We conclude that the linear precoding technique MMSE achieves the maximum EE more than ZF and MRTbecause the MMSE is able to make the massive MIMO system less sensitive to SNR at an increased number of antennas.
Volume: 7
Issue: 6
Page: 2977-2985
Publish at: 2017-12-01

Potential and Electric Field Characteristics of Broken Porcelain Insulator

10.11591/ijece.v7i6.pp3114-3123
H. Rosli , N. A. Othman , N. A. M. Jamail , M. N. Ismail
Overhead line insulators can be damaged for various reasons during their service life. Porcelain or glass insulators once damaged can affect the reliability of power system networks. This paper presents the study of voltage and electric characteristics along the surface of a broken porcelain insulator located in a string of 10 unit insulators. Three models of broken porcelain insulators were being proposed and the analysis results on voltage and electric characteristics were individually collected. The broken porcelain insulator with the most significant effect were then being investigated in the strings of 10 unit insulators. The finite element software of Quickfield was used to analyze the voltage and electric characteristics. Form the presented results, it is proven that the single porcelain insulators with broken shed at the nearest to the electrode terminal gave the most significant effect of voltage and electric field distribution pattern along the creepage distance. However, when this type of broken insulator was included in a string of 10 unit insulators, maximum average value of voltage achieved once the broken insulator was located at the HV terminal. Meanwhile, the highest electric field strength was recorded when the broken insulator was located in the middle of the string.
Volume: 7
Issue: 6
Page: 3114-3123
Publish at: 2017-12-01

Enhanced Zeta Converter for DC Bus Voltage Regulation

10.11591/ijpeds.v8.i4.pp1503-1511
P. Suresh , D. Kirubakaran
In this paper, an Enhanced Zeta Converter (EZC) along with a high voltage gain converter is presented for DC Bus voltage regulation. The enhanced zeta converter consists of capacitors connected in parallel with the conventional zeta structure. The proposed zeta converter is applied to the Photo Voltaic system (PV) The well known Maximum Power Point Tracking (MPPT)     P & O algorithm is used to extract maximum power from the photovoltaic system. The increased voltage is obtained with reduced number of switches using the proposed structure. The results to the proposed structure are compared with the conventional topology. The proposed converter is simulated using MATLAB and the same is verified with the hardware.
Volume: 8
Issue: 4
Page: 1503-1511
Publish at: 2017-12-01

A Complete Modeling and Control for Wind Turbine Based of a Doubly Fed Induction Generator using Direct Power Control

10.11591/ijpeds.v8.i4.pp1954-1962
Fawzi Senani , Abederrezak Rahab , Hocine Benalla
The paper presents the complete modeling and control strategy of variable speed wind turbine system (WTS) driven doubly fed induction generators (DFIG). A back-to-back converter is employed for the power conversion exchanged between DFIG and grid. The wind turbine is operated at the maximum power point tracking (MPPT) mode its maximum efficiency. Direct power control (DPC) based on selecting of the appropriate rotor voltage vectors and the errors of the active and reactive power, the control strategy of rotor side converter combines the technique of MPPT and direct power control. In the control system of the grid side converter the direct power control has been used to maintain a constant DC-Link voltage, and the reactive power is set to 0. Simulations results using MATLAB/SIMULINK are presented and discussed on a 1.5MW DFIG wind generation system demonstrate the effectiveness of the proposed control.
Volume: 8
Issue: 4
Page: 1954-1962
Publish at: 2017-12-01

Modeling of Lightning Strike Events, and it’s Correlational with Power Outages in South-West Coast, Nigeria

10.11591/ijece.v7i6.pp3262-3270
Melodi A. O. A. O. , Olayinka Matthew Oyeleye
This paper aimed to model lightning strike events and evaluate its correlation with power outages in a Nigerian power distribution system. A specified coastal distribution network of southwest Nigeria was selected as a case study. Zone-specific records of cloud-to-ground lightning strikes for 84 months were obtained from the Nigerian Meteorological Agency (NiMet); records of power outage frequencies and durations for 36 months were obtained at the substations of the selected distribution network. Using numerical statistical analysis techniques, lightning activity in the system area were characterized in relative frequency terms, and correlation statistics were evaluated and analyzed for power outages and lightning events on the 11kV, 33kV, and 132kV voltage levels. An analysis of the results shows that the modelled lightning strike events patterns are closely related but the expected frequencies vary from one zone to another; and there is correlation between lightning strike and power outages in the distribution networks, which is strong and positive at the 33 kV and 132 kV circuits. In essence, the results provided salient information, useful for power systems lightning protection review, management and planning in the area.
Volume: 7
Issue: 6
Page: 3262-3270
Publish at: 2017-12-01

VHDL Based Maximum Power Point Tracking of Photovoltaic Using Fuzzy Logic Control

10.11591/ijece.v7i6.pp3454-3466
Doaa M. Atia , Hanaa T. El-madany
It is important to have an efficient maximum power point tracking (MPPT) technique to increase the photovoltaic (PV) generation system output efficiency. This paper presents a design of MPPT techniques for PV module to increase its efficiency. Perturb and Observe method (P&O), incremental conductance method (IC), and Fuzzy logic controller (FLC) techniques are designed to be used for MPPT. Also FLC is built using MATLAB/ SIMULINK and compared with the FLC toolbox existed in the MATLAB library. FLC does not need knowledge of the exact model of the system so it is easy to implement. A comparison between different techniques shows the effectiveness of the fuzzy logic controller techniques.  Finally, the proposed FLC is built in very high speed integrated circuit description language (VHDL). The simulation results obtained with ISE Design Suite 14.6 software show a satisfactory performance with a good agreement compared to obtained values from MATLAB/SIMULINK. The good tracking efficiency and rapid response to environmental parameters changes are adopted by the simulation results.
Volume: 7
Issue: 6
Page: 3454-3466
Publish at: 2017-12-01

The Combination of Newton-Raphson Method and Curve-Fitting Method for PWM-based Inverter

10.11591/ijpeds.v8.i4.pp1919-1931
Majdee Tohtayong , Sheroz Khan , Mashkuri Yaacob , Siti Hajar Yusoff , Nur Shahida Midi , Musse Mohamud Ahmed , Fawwaz Wafa , Ezzidin Aboadla , Khairil Azhar Aznan
This paper presents the combination of two different methods to perform the waveform analysis for PWM-operated inverter. The two techniques are Newton-Raphson method and Curve-Fitting as a PWM concept to operate PWM-based inverter, the proper solutions of switching angles can valuate the initial values by using the Newton-Raphson method with the wide-step calculation of modulation indices. The solutions are then compared using a curve in order to study the behavior. Then, the Curve-Fitting method is used to estimate the missing solutions between any points of wide-step calculation. This combination method can estimate the probable solutions that cannot be solved by Newton-Raphson method in a wide-ranging of the modulation index and reduce the calculation time. PWM-based inverter, which is obtained the switching angles by Newton-Raphson method and the combination of two different methods, is verified by the simulation results showing faster performance with improved Total Harmonic Distortion (THD) than both methods alone when compared the same values of switching angles.
Volume: 8
Issue: 4
Page: 1919-1931
Publish at: 2017-12-01

Reviewing the Effectivity Factor in Existing Techniques of Image Forensics

10.11591/ijece.v7i6.pp3558-3569
Shashidhar TM , KB Ramesh
Studies towards image forensics are about a decade old and various forms of research techniques have been presented till date towards image forgery detection. Majority of the existing techniques deals with identification of tampered regions using different forms of research methodologies. However, it is still an open-end question about the effectiveness of existing image forgery detection techniques as there is no reported benchmarked outcome till date about it. Therefore, the present manuscript discusses about the most frequently addressed image attacks e.g. image splicing and copy-move attack and elaborates the existing techniques presented by research community to resist it. The paper also contributes to explore the direction of present research trend with respect to tool adoption, database adoption, and technique adoption, and frequently used attack scenario. Finally, significant open research gap are explored after reviewing effectiveness of existing techniques.
Volume: 7
Issue: 6
Page: 3558-3569
Publish at: 2017-12-01

MRAS-based Sensorless Speed Integral Backstepping Control for Induction Machine, using a Flux Backstepping Observer

10.11591/ijpeds.v8.i4.pp1650-1662
Mohamed Horch , Abdelmadjid Boumediene , Lotfi Baghli
This paper presents a study concerning a sensorless vector control of an induction machine fed by a voltage source inverter. The aim is to provide a scheme to control the speed and the rotor flux using a sensorless integral backstepping control approach. The rotor speed estimation is done by an observer using the model reference adaptive system (MRAS) technique whereas the nonlinear backstepping observer is used to get the rotor flux. The main objective is to achieve a robust control, adaptive and efficient, which will allow us to test and evaluate the performance of the proposed observer, combined with a sensorless control of the induction machine. Tests and validation are done using numerical simulations with MATLAB/SIMULINK-PSB (Power System Block set) toolbox. The results show good performance in terms of robustness regarding machine parameter variations and show the excellent quality of the control law associated with the observer, despite the observability problems when the machine operates at low speed.      
Volume: 8
Issue: 4
Page: 1650-1662
Publish at: 2017-12-01

A Survey on Automatically Mining Facets for Web Queries

10.11591/ijece.v7i6.pp3700-3704
Duhita Pawar , Vina M. Lomte
In this paper, a detailed survey on different facet mining techniques, their advantages and disadvantages is carried out. Facets are any word or phrase which summarize an important aspect about the web query. Researchers proposed different efficient techniques which improves the user’s web query search experiences magnificently. Users are happy when they find the relevant information to their query in the top results. The objectives of their research are: (1) To present automated solution to derive the query facets by analyzing the text query; (2) To create taxonomy of query refinement strategies for efficient results; and (3) To personalize search according to user interest.
Volume: 7
Issue: 6
Page: 3700-3704
Publish at: 2017-12-01

Simulation of an Indirect Rotor Flux Oriented Induction Motor Drive using Matlab/Simulink

10.11591/ijpeds.v8.i4.pp1693-1704
Vivek V. Puranik , Vijay N. Gohokar
Indirect Field Oriented Control (IFOC) is very popular technique in industries due to its simple designing and structure, in comparison to the direct method since it requires flux and torque estimators. This paper presents detail calculation of all values needed for the development of an indirect rotor flux oriented induction motor model fed by a current-controlled voltage source inverter. With the calculated values for 1 hp 50 Hz 3 phase induction motor; an indirect rotor flux oriented model is developed using MATLAB/Simulink. The simulation results are outlined and discussed.
Volume: 8
Issue: 4
Page: 1693-1704
Publish at: 2017-12-01
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