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28,188 Article Results

A Unified Quality Control Model for E-Learning Systems

10.11591/ijece.v7i3.pp1355-1366
Khalid Hamed Allehaibi , Nasser Nammas Albaqami
Defining, measuring, and achieving quality of e-learning systems are not an easy task. Accordingly, one of the most essential goals for the higher educational institutes is how to reach a high and satisfied level of quality in their learning systems. Achieving such level needs adequate and continuous improvements for the whole e-learning environment elements. Therefore, we aim in our work to construct a unified framework for total quality management system (TQMS) that attempt to satisfy the quality requirements, needs, and standards. The objective of this paper is to present a quality control model for e-learning system that adopts the e-learning platform according to the on-line determination of both user's requirements and global standards. This paper proposed software architecture of quality Management framework for e-learning that could be adopted by different higher education institutes to control the quality of the e-learning process, and assure the quality of the e-learning process outcome. The proposed framework is based on a tri-dimensions quality model. The three dimensions are set of quality requirements for e-learning environment represented in Quality Assurance (QA) policies that will be formalized by using policy based approach, the specifications of e-learning platform that provide learning and teaching activities, and quality control process loop. The architecture for monitor and ensure quality control of the QA policies for e-learning system will deliver the whole learning services in an optimal way. It is also flexible and can be implemented over any e-learning system.
Volume: 7
Issue: 3
Page: 1355-1366
Publish at: 2017-06-01

Three-Phase Three-Level Soft Switching Dc-Dc Converter for Industrial Applications

10.11591/ijpeds.v8.i2.pp785-794
J. Sivavara Prasad , Y.P. Obulesh , Ch. Sai Babu
In high power DC applications, the single-phase DC-DC converter will face large voltage and current stress in each control switch and thereby the power handling capacity is less. To overcome this problem, three-phase DC-DC converter is used and it is suitable for high power applications with reduced number of switches as compared with the conventional topologies. The asymmetrical duty cycle control is considered to operate the switches under soft switching and hence the switching losses are reduced. The transformer leakage inductances are used along with junction capacitances in order to form resonance and hence ZVS commutation is possible in a wider load range. The modified phase shift control method is used for the proposed converter.The operational modes and design equations of the proposed converter have been observed. The simulation is carried out with a load of 1000W for validating the proposed work.
Volume: 8
Issue: 2
Page: 785-794
Publish at: 2017-06-01

Improved Sensorless Direct Torque Control of Induction Motor Using Fuzzy Logic and Neural Network Based Duty Ratio Controller

10.11591/ijai.v6.i2.pp79-90
Sudheer H , Kodad SF , Sarvesh B
This paper presents improvements in Direct Torque control of an induction motor using Fuzzy logic with Fuzzy logic and neural network based duty ratio controller. The conventional DTC (CDTC) of induction motor suffers from major drawbacks like high torque and flux ripples and poor transient response. Torque and flux ripples are reduced by replacing hysteresis controller and switching table with Fuzzy logic switching controller (FDTC). In FDTC the selected switching vector is applied for the complete switching time period. The FDTC steady state performance can be improved by using duty ratio controller, the selected switching vector is applied only for the time determined by the duty ratio (δ) and for the remaining time period zero switching vector is applied. The selection of duty ratio using Fuzzy logic and neural networks is projected in this paper. The effectiveness proposed methods are evaluated using simulation by Matlab/Simulink.
Volume: 6
Issue: 2
Page: 79-90
Publish at: 2017-06-01

Improving Voltage Profile and Reducing Network Losses by Integration of Wind Farm and Thyristor-Switched Series Capacitors

10.11591/ijaas.v6.i2.pp145-155
Milad Gheydi , Farshid Abdolahnejad Baroogh
This paper aims at improving voltage profile and reducing the losses of active and reactive powers. The impact of wind turbines on voltage profile and power losses in critical buses is evaluated. Wind turbines, reactive power resources, i.e. thyristor-switched series capacitors, are connected to the network in mentioned states. In this study different conditions are individually and simultaneously considered with/without the wind turbines and thyristor-switched series capacitors in normal states of the network. Next, voltage profile, active power, reactive power, and the network losses are dealt with in the presence/absence of wind turbines and thyristor-switched series capacitors considering a sudden fault occurred in one power line, and the simulation results are compared with each other. The results indicate that using thyristor-switched capacitors together with the wind farm can provide enough active and reactive power for the network which increases the network capacity and decreases its losses using genetic algorithms.
Volume: 6
Issue: 2
Page: 145-155
Publish at: 2017-06-01

Design of Converters for PV System Under Partial Shading Conditions

10.11591/ijaas.v6.i2.pp77-88
M. Kowsalya , K. Balsubramanyam
This paper presents a maximum power generation with the interconnection of photovoltaic modules under partially shaded and/or mismatching conditions. The partial shading condition reduces power level of each module. The reduction in power due to the partial shading will be compensated by the bidirectional converter. The proposed system consisting of two and three PV modules connected in series under partial shading conditions which are capable of increasing the power levels up to 50% compared to conventional by-pass diode structure. In general ‘n’ number of modules connected in series so that the maximum power gain will be expected to (100/n) %. This is achieved by developing the new control strategy in which the correct adjustment of converter duty ratio under partially shading conditions. The novel control scheme is developed by using analysis of the power converters. The proposed scheme was verified in MATLAB/SIMULINK.
Volume: 6
Issue: 2
Page: 77-88
Publish at: 2017-06-01

Voltage Stability Improvement in Fourteen Bus System during Line Interruption using DPFC

10.11591/ijpeds.v8.i2.pp705-711
Akhib Khan Bahamani , G.M. Sreerama Reddy , V. Ganesh
DPFC is proposed in the present work to improve voltage stability of fourteen bus system during line interruption. The voltage across the load decreases due to the interruption of the line. State space method is used to calculate Line currents and bus voltages. The ability of DPFC to bring voltage, real power and reactive power to normal level is presented in this paper. The simulation results for healthy system, line interrupted system without DPFC and with DPFC are presented. The results of comparative study are presented to show the improvement in power quality. The simulation studies indicate that the power flow with DPFC during line outage is almost equal to the power during healthy condition.
Volume: 8
Issue: 2
Page: 705-711
Publish at: 2017-06-01

Students’ Critical Thinking Improvement Through PDEODE and STAD Combination in The Nutrition and Health Lecture

10.11591/ijere.v6i2.7589
Tabitha Wulandari , Mohamad Amin , Siti Zubaidah , Mimien IAM
Students’ critical thinking skills are very important in the 21st century. Learning strategies can play a role in enhancing students’ critical thinking skills in the Nutrition and Health lecture. The results of a survey in 2013 showed that the implementation of learning strategies had not given students the opportunity to practice their critical thinking skills optimally. The new strategy, a combination of PDEODE and STAD, can be used to overcome the occurring problems. The purpose of this research was to determine the increase in students’ critical thinking skills in the nutrition and health lecture after they were taught using a combination of PDEODE and STAD. This was a pre-experimental research using a one group pretest-posttest research design. The samples of this research were one class consisting of 41 university students. The results of the test were analyzed with quantitative methods, by using statistical analysis, paired samples T-test, and to know the effectiveness using gain scores. The results showed that the significance was 0.000 (p <0.05) and the gain score was 0.58. Thus, it can be concluded that the strategy of combining PDEODE and STAD can effectively improve the students’ critical thinking skills in the nutrition and health lecture.
Volume: 6
Issue: 2
Page: 110-117
Publish at: 2017-06-01

Classification of Partial Discharge Sources using Statistical Approach

10.11591/ijeecs.v6.i3.pp537-543
L. W. Ren , M. S. Abd Rahman , A. Mohd Ariffin
In high-voltage (HV) power equipment, degradation of insulation has been main concern for protection of equipment. This is due to occurrence of partial discharges (PD) activity within HV insulating systems which can be initiated from different types of local internal or external defects. Thus, partial discharge (PD) identification and classification are important for diagnostic insulation systems problems in order to ensure maintenance process can be carried out effectively and hence improve reliability and durable operation of HV equipment. In this work, the relation of the observable statistical characteristics from PD data with the characteristic of the defect is an important factor to determine the defect inside insulation system. Ultimately, the statistical parameters obtained from PD data can be used to classify different PD sources occur inside HV insulation system. Thus, the objective of this paper is to produce a unique pattern according to discharge source using statistical method. Several statistical parameters such as mean, variance, standard deviation, skewness and kurtosis have been used and analysed.
Volume: 6
Issue: 3
Page: 537-543
Publish at: 2017-06-01

The Modeling of SVC for the Voltage Control in Power System

10.11591/ijeecs.v6.i3.pp513-519
Nor Adni Binti Mat Le , W Mohd Nazmi bin W Musa , Nurlida binti Ismail , Nurul Huda binti Ishak , Nur Ashida binti Salim
One of the major causes of voltage instability in power system is the reactive power limit. Therefore, this paper aims to analyze the effect of Static Var Compensator (SVC) on voltage stability of a power system. There are many ways to control the voltage, but in this paper only focus on the SVC and IEEE-9 buses. The SVC circuit and IEEE-9 buses were designed and modelled in Power World. The Newton Raphson method was applied to compute the load flow solution. Then, the reactive power (Q) was injected to SVC and the effect of SVC on IEEE 9-buses were studied. The analysis of voltage control was considered the conditions of fault occurred at the bus. The simulation results obtained in Power World demonstrate that the improvement voltage in the IEEE 9-buses when the Q was injected into SVC circuit. Besides, the QV curve was plotted to show the sensitivity and variation bus voltages with respect to the Q injection.
Volume: 6
Issue: 3
Page: 513-519
Publish at: 2017-06-01

A Monitoring System of Battery LiFePO4 for Assessment Stand-Alone Street Light Photovoltaic System Based on LabVIEW Interface for Arduino

10.11591/ijpeds.v8.i2.pp926-934
Anif Jamaluddin , Anafi Nur’aini , Arif Jumari , Agus Purwanto
The paper presents monitoring and assessment system of battery LiFePO4 performance that applied on a stand-alone photovoltaic system. A stand-alone photovoltaic system is constructed by photovoltaic module 50 Watt Peak, Pulse Width Modulation solar controller, battery module LiFePO4 battery (12 Volt 21 Ah), and street light 10 watt. To overcome the data acquisition, a simple monitoring system has been designed using LabVIEW Interface for Arduino. The voltage divider, current sensing type ACS712, temperature and humidity sensor, and light intensity sensor were used to collect the data. The data processed by a dual microcontroller (ATmega-2560 and ATmega-328) and LabVIEW software on Personal Computer. The assessment of stand-alone photovoltaic system includes battery LiFePO4 performance (State of Charge, voltage, and current) during charging and discharge condition, the power efficiency, and environmental condition (temperature, humidity and solar radiation). In the discharge condition, voltage battery and State of Charge decreased about 40% after 12 hours operated. In the charge condition, the current battery fluctuated in the range of 0.10 A-1.95 A and the State of Charge increased up to 25% after 8 hours operated. It indicates that the power of the battery has always lacked.
Volume: 8
Issue: 2
Page: 926-934
Publish at: 2017-06-01

Teaching New Vocabulary to Iranian Young FL Learners: Using Two Methods Total Physical Response and Keyword Method

10.11591/ijere.v6i2.7593
Amir Toghyani Khorasgani
Early language learning for children is increasingly common, and the majority of parents and the public do not see it as superfluous or overburdening children. Moreover, teaching a foreign language to very young children has been an increasingly dominant trend in most globalized societies. While there is abundant literature that supports teaching a foreign language at an early age through language immersion programs, little is known about the efficiency of strategies used to explicitly teach new vocabulary words in a foreign language to young learners. This empirical investigation aimed to assess and compare the efficiency of two mnemonics that have been traditionally used to explicitly teach new foreign language words: the Keyword Method (KWM) and the Total Physical Response (TPR). Results indicate that the KWM is more effective than TPR in teaching new vocabulary words in a foreign language to early elementary school children.
Volume: 6
Issue: 2
Page: 150-156
Publish at: 2017-06-01

Speed and Position Estimator of Dual-PMSM for Independent Control Drives using Five-Leg Inverter

10.11591/ijpeds.v8.i2.pp612-622
Jurifa Mat Lazi , Zulkifilie Ibrahim , MD Hairul Talib , Auzani Jidin , Tole Sutikno
Nowadays, A lot of industry requires Multi Motor System (MMS) applications such as propulsion and traction power, HEV, conveyer and air-conditioner. The Conventional arrangement for MMS usually done by cascading the motors drives which each drives has individual inverter. Part of MMS, Dual-Motor drives fed by a single inverter is being paid attention by the researchers. Dual-motor drives using a single three-leg inverter has its limitation in the case of different operating conditions and independent speed control requirement. Therefore, dual-Motor drives using a single Five-leg Inverter (FLI) was proposed for independent control for both motors. In PMSM drives, the information of the feedback speed and rotor angular position is compulsory for variable speed drives. Conventional solution is by using speed sensor which will increase size, cost, extra hardwire and feedback devices, especially for the case of dual-PMSM drives. The best solution to overcome this problem is by eliminating the usage of speed and position sensors for Dual-motor drives. This paper presents a new sensorless strategy using speed and position estimator for Independent Dual- Permanent Magnet Synchronous Machine (PMSM) drives which utilize Five-Leg Inverter (FLI). The proposed strategy is simulated using MATLAB/Simulink to evaluate the overall motor drive performance. Meanwhile the experimental set-up is connected to dSPACE 1103 Board. The experimental results demonstrate that the proposed estimator is successfully managed to control the Dual-PMSM drives for variation of speed and for different direction applications.
Volume: 8
Issue: 2
Page: 612-622
Publish at: 2017-06-01

Performance Analysis of Modified SVPWM Strategies for Three Phase Cascaded Multi-level Inverter fed Induction Motor Drive

10.11591/ijpeds.v8.i2.pp835-843
Ravikumar Bhukya , P. Satish Kumar
This paper presents new modified space vector pulse width modulation techniques (Phase disposition-Space vector pulse width modulation, Alternative Phase Opposition disposition- Space vector pulse width modulation and Phase Opposition disposition-Space vector pulse width modulation) are analyzed for three-phase cascaded multi-level inverter fed induction motor from the point of view of the Phase voltages, line voltage, stator current,speed,torque and Total harmonic distortion.in the proposed modified technique the reference signals are generated by adding offset voltage to the reference phase voltages.This modified SVPWM technique does not involve region indentification,sector identification for switching vector determination as are required in the conventional multi level SVPWM technique,it is also reduces the computation time compared to the conventional space vector PWM technique.The necessary calculations for generation of new modified SVPWM for the modulation strategies have presented in detail.  It is observed that the modified SVPWM modulation ensures excellent, close to optimized pulse distribution results and THD is compared to for five-level, seven-level, nine-level and eleven-level Cascaded H-Bride Multi-level Inverter fed to Induction motor. Theoretical investigations were confirmed by the digital simulations using MATLAB/SIMULINK software.
Volume: 8
Issue: 2
Page: 835-843
Publish at: 2017-06-01

Idiosyncratic Shocks, Child Labor and School Attendance in Indonesia

10.11591/ijere.v6i2.7588
Bayu Kharisma
This paper investigates the effect of various idiosyncratic shocks against child labor, child labor hour and school attendance. Also, the role of the assets held by households as one of the coping strategies to mitigate the effects of shocks. The results show that various idiosyncratic shocks that encourage child labor is generally caused by crop loss, a disease suffered by the head or member of the household, a decrease in household income due to lower prices and the quantity produced and the death of the head or a family member. This indicates that households are not sheltered from the idiosyncratic shocks and restricted access to formal and informal institutions. Other findings show a variety of idiosyncratic shocks does not affect child labor hour and the school attendance. Additionally, household assets play an important role in reducing the number of child labor and increase school attendance but do not affect the child labor hour during a variety of idiosyncratic shocks.
Volume: 6
Issue: 2
Page: 100-109
Publish at: 2017-06-01

Improved Fully Differential Low Power Active Filter

10.11591/ijpeds.v8.i2.pp747-754
Imane Halkhams , Mahmoud Mehdi , Said Mazer , Moulhime El Bekkali , Wafae El Hamdani
This paper relates the new topology and simulations of a fully differential CMOS active filter for mm wave band applications. The advantages of the differential topology over the single ended one are discussed and the quality factor is tuned to insure application requirements, including narrow bandwidth and high selectivity due to a differential negative resistance that reuses the filter’s current. Using this topology enables independent tuning of the quality factor and low power consumption while compensating the resistive loss of the filter. Very high filter performance was obtained with the simulated active inductor based active filter that was designed using CMOS 0.35 µm technology from AMS foundry and that resonates at 30 GHz with a high quality factor of Q > 500.
Volume: 8
Issue: 2
Page: 747-754
Publish at: 2017-06-01
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