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29,922 Article Results

Design and analysis of a multi-agent e-learning system using prometheus design tool

10.11591/ijai.v10.i1.pp9-23
Kennedy E. Ehimwenma , Sujatha Krishnamoorthy
Agent unified modeling languages (AUML) are agent-oriented approaches that supports the specification, design, visualization and documentation of an agent-based system. This paper presents the use of prometheus AUML approach for the modeling of a Pre-assessment System of five interactive agents. The Pre-assessment System, as previously reported, is a multi-agent-based e-learning system that is developed to support the assessment of prior learning skills in students so as to classify their skills and make recommendation for their learning. This paper discusses the detailed design approach of the system in a step-by-step manner; and domain knowledge abstraction and organization in the system. In addition, the analysis of the data collated and models of prediction for future pre-assessment results are also presented.
Volume: 10
Issue: 1
Page: 9-23
Publish at: 2021-03-01

Finite frequency H∞control design for nonlinear systems

10.11591/ijpeds.v12.i1.pp567-575
Zineb Lahlou , Abderrahim EL-Amrani , Ismail Boumhidi
The work deals finite frequency H∞ control design for continuous time nonlinear systems, we provide sufficient conditions, ensuring that the closed-loop model is stable. Simulations will be gifted to show level of attenuation that a H∞ lower can be by our method obtained developed where further comparison.
Volume: 12
Issue: 1
Page: 567-575
Publish at: 2021-03-01

Investigation of faulty behavior of the sensorless control switched reluctance motor drives

10.11591/ijpeds.v12.i1.pp88-98
Alexander Krasovsky
The paper presents the results of studies of abnormal conditions in a switched reluctance drive (SRD) due to failures in control algorithms. It discusses one of the most common control algorithms for these drives without the use of sensors, which is simple and easy to configure. The practical application of this algorithm of control showed that various anomalous phenomena could occur in it, expressed, for example, in a sharp increase in the amplitude of the phase current of the motor, and violation of the switching mode. The reasons for these phenomena are not evident and hard to analyze due to the nonlinearity of this drive. To identify these causes and search for measures to eliminate them, we used simulation in the environment of MATLAB/Simulink. The adequacy and effectiveness of the application of the developed simulation models we confirmed by a comparison of the simulation results and the full-scale experiment on real equipment. Theoretical studies and simulation results are in good agreement with the experimental results.
Volume: 12
Issue: 1
Page: 88-98
Publish at: 2021-03-01

Crucial problems in arranged the lesson plan of vocational teacher

10.11591/ijere.v10i1.20604
Muhammad Nurtanto , Nur Kholifah , Alias Masek , Putu Sudira , Achmad Samsudin
This study aimed to explore the implementation of the 2013 curriculum in vocational schools, Banten in terms of the readiness and quality of the learning tools that have been prepared. A total of 957 respondents from 2017 to 2018, consisting of four cities and three districts in Banten Province were involved in the training and mentoring program, namely vocational teachers and vice-principals in the curriculum field. Data were collected using questionnaire sheets, FGD notes, and observation check dates. The data obtained are analyzed and interpreted based on the specified categories. The results showed that: 1) Teacher readiness for learning tools in the components a) Core Competencies (CC) and Basic Competencies (BC) analysis of 45.31%, b) Program mapping of 38.37%, learning plan preparation of 39.45% and c) Learning evaluation of 36.78%; 2) The quality of lesson plan (LP) the science lesson plan analysis instrument (SLPAI) based is divided into two groups. The category "Quality" in the instructional program and instructional plan aspects, and the category "Moderate" in the instructional media and assessment and others aspects; and 3) The difficulty of learning device components, including authentic assessment, use of methods, literacy approaches, and lesson planning. The implementation of training, mentoring, and supervision programs are adjusted to the experience of vocational teachers taking into account the teacher's involvement in the implementation of the curriculum, age, and school readiness.
Volume: 10
Issue: 1
Page: 345-354
Publish at: 2021-03-01

Fault diagnosis of a squirrel cage induction motor fed by an inverter using lissajous curve of an auxiliary winding voltage

10.11591/ijeecs.v21.i3.pp1299-1308
Yakout Khadouj Jelbaoui , El Menzhi Lamiaà , Abdallah Saad
The development of electronic power components has allowed the increase of the induction machine performance. Indeed, monitoring squirrel cage induction motors driven through rectifiers and inverters has been a major concern. This paper presents a new method to diagnose the combination inverter-machine faults. This technic considers an auxiliary winding which is a small coil inserted between two stator phases. It is based on Lissajous curve of this auxiliary winding voltage Park components. For this purpose, modeling the electromechanical conversion chain is necessary. The focus will particularly be on modeling both the squirrel cage induction machine and the inverter in a non-defected case which is a reference. Moreover, the explicit expressions developed for the inserted winding voltage and its Park components will be presented. The simulation results show the effectiveness of the proposed method.
Volume: 21
Issue: 3
Page: 1299-1308
Publish at: 2021-03-01

Effect of blade pitch angle on the aerodynamic characteristics of a twisted blade horizontal axis wind turbine based on numerical simulations

10.11591/ijpeds.v12.i1.pp511-519
Rajendra Roul , Awadhesh Kumar
The present work includes a study of the impact of varying pitch angles and angular velocity on the performance parameters of a horizontal axis wind turbine using computational fluid dynamics. Simulations have been made using commercial Ansys 15 software. Seven pitch angles are chosen for study, i.e., 0° , 5 ° , 10° , 15° , 20° , 25° , and 28°, and two angular velocity values of 1.57 rad/sec and 2.22 rad/sec are used for simulation. The turbulence model used is shear stress transport (SST) K-ω. A detailed study of the influence of pitch angle on the aerodynamic characteristics of the wind turbine is highlighted. Performance parameters like torque and power have been found to exhibit random variability with a change in wind velocity and pitch angle. The verification of computational fluid dynamics (CFD) with the standard empirical formula is highlighted. The best pitch angle is noted for the best power coefficient.
Volume: 12
Issue: 1
Page: 511-519
Publish at: 2021-03-01

A hybrid de-noising method for mammogram images

10.11591/ijeecs.v21.i3.pp1435-1443
Rashid Mehmood Gondal , Saima Anwar Lashari , Murtaja Ali Saare , Sari Ali Sari
In general, mammogram images contaminated with noise which directly affect images quality. Several methods have been proposed to de-noise these images, however, there is always a risk of losing valuable information. In order to overcome the loss of information, the present study proposed a hybrid denoising method for mammogram images. The proposed hybrid method works in two steps: Firstly, preprocessing with mathematical morphology was applied for image enhancement. Secondly, global unsymmetrical trimmed median filter (GUTM) is applied to de-noise image. Experimental results prove that proposed method work well for mammogram images. Hence, the study provided an alternative method for denoising mammogram images.
Volume: 21
Issue: 3
Page: 1435-1443
Publish at: 2021-03-01

Assessing students’ errors in mathematical translation: From symbolic to verbal and graphic representations

10.11591/ijere.v10i1.20819
Nurrahmawati Nurrahmawati , Cholis Sa'dijah , Sudirman Sudirman , Makbul Muksar
Translation skills are very important possessed by students, but currently, there are still many students who have difficulty in translating between representations. The purpose of this study is to analyze students' errors in translating from symbolic representations to verbal and graphic representations. This research was descriptive study with qualitative approach. Tests are given to junior high school students. From the results of data analysis, it is obtained that in translating from symbolic to verbal forms (problems in daily life) that are following the given system of equations, students are still unable to make representations correctly. When students are asked to translate into graphical form, students are still unable to draw complete graphs and errors made by students are misinterpretation and implementation errors, so they cannot maintain the semantic congruence between source representation and target representation. Based on this, it is necessary to make a learning plan that can improve students’ ability to translate between representations.
Volume: 10
Issue: 1
Page: 115-125
Publish at: 2021-03-01

Load flow analysis using Newton-Raphson method in presence of distributed generation

10.11591/ijpeds.v12.i1.pp489-498
Tebbakh Noureddine , Labed Djamel
Distributed generations (DG), specially including renewable sources such as wind and sun are offering several opportunities for the currently in existence distribution networks and becoming one of the keys of treatment of its problems. Knowing the effects of each kind of DG on distribution networks is a primordial task because DG impacts differ from one kind to another. In this paper, we have analyzed and compared the effects of two kinds of DG, DG which provides real power only and DG which provides real power and reactive power at the same time connected at the critical bus in DN on the voltage profile, real and reactive power losses. We have proposed Newton Raphson method using Matlab to investigate the impacts of these two kinds of DG on 57-bus IEEE distribution test system. The obtained results have been exposed in detail at the end of this paper.
Volume: 12
Issue: 1
Page: 489-498
Publish at: 2021-03-01

Harmonics elimination for DC/DC power supply based on piezoelectric filters

10.11591/ijpeds.v12.i1.pp356-363
Hasan Ma Almgotir , Enaam A. Khaliq Ali , Wedian H. Abd al ameer , Mustafa A. Fadel Al-Qaisi
This research presents a study, modelling and simulation of the piezoelectric material work as filters (piezoelectric filter) used to eliminate the harmonics in power electronic circuits, high order harmonics are generating due to the high switching frequencies and circuit equipment, detailed simulation is achieved for the piezoelectric filter tested in full-bridge DC/DC converter circuit with resistive load works as dc power supply (12 to 48 volt). As a result, the uses of piezoelectric filters have a great impact on harmonics elimination, which leads to reduce the overall total harmonic distortion leads to increase the efficiency, as well as the output voltage from the dc power supply remain constant by varying the load resistance over a wide range. The dc power supply circuit including the piezoelectric filter has been simulated using PSIM (V9.1) power electronic circuit simulation software.
Volume: 12
Issue: 1
Page: 356-363
Publish at: 2021-03-01

Sectoral dual-polarized MIMO antenna for 5G-NR band N77 base station

10.11591/ijeecs.v21.i3.pp1611-1621
Muhsin Muhsin , Afina Lina Nurlaili , Aulia Saharani , Indah Rahmawti Utami
Massive internet of things (IoT) in 5G has many advantages as a future technology. It brings some challenges such as a lot of devices need massive connection. In this case, multiple-input multiple-output (MIMO) systems offer high performance and capacity of communications. There is a challenge of correlation between antennas in MIMO. This paper proposes three-sectors MIMO base station antenna for 5G-New Radio (5G-NR) band N77 with dual polarized configuration to reduce the correlation. The proposed antenna has a maximum coupling of -16.90 dB and correlation below 0.01. The obtained bit error rate (BER) performance is very close to non-correlated antennas with bandwidth of 1.87 GHz. It means that the proposed antenna has been well designed.
Volume: 21
Issue: 3
Page: 1611-1621
Publish at: 2021-03-01

Validating the teaching, learning, and assessment quality of Malaysian ECCE instrument

10.11591/ijere.v10i1.20857
Hishamuddin Ahmad , Nordin Mamat , Mazlina Che Mustafa , Syahida Iryani Mohd Yusoff
Several instruments that measure the teaching, learning, and assessment quality have been developed and published. However, a psychometrically sound instrument to measure teaching, learning, and assessment quality in early childhood care and education that suitable for the Malaysian context needs to be validated. Therefore, this study aimed to validate on teaching, learning, and assessment quality in early childhood care and education instrument, which contains 68 items. The sample comprised 3,498, selected by stratified random sampling from a population of all Malaysian kindergarten teachers. Data were analyzed based on the Polytomous Item Response Theory (IRT) using the Xcalibre software. Samejima's Graded Rating Model (SRGM) was found to be the fit model with the data. Unidimensionality assumption and local independence were tested using the exploratory factor analysis and were fulfilled. The instrument’s reliability was overall very good (α=0.966) and the construct validity was also fairly fulfilled with the value of 58.17% total variance explained. Therefore, this instrument is suggested to be used as fairly to measure the quality of Malaysian early childhood care and education among teachers so that appropriate follow-up actions can be implemented towards the betterment of early childhood education quality.
Volume: 10
Issue: 1
Page: 135-141
Publish at: 2021-03-01

Multilevel level single phase inverter implementation for reduced harmonic contents

10.11591/ijpeds.v12.i1.pp314-324
Taha Ahmed Hussein
Selective harmonic elimination technique SHE is adopted in this work to reduce the harmonic contents in single phase cascaded multilevel inverter. The firing instants for the electronic switches MOSFETs in the inverter are calculated off line for five level to thirteen level inverter. An Arduino microcontroller is programmed to cope with different topologies of the multilevel inverter. The implemented multi-level (MLI) inverter results are compared with Simulink simulation program and are found very close to each other. SHE technique works at system frequency (50 Hz or 60 Hz) and the switching losses are very small. The sinusoidal pulse width modulation SPWM requires a carrier frequency not less 20 times the system frequency so SHE approach is found to be superior compared with SPWM. Also, SHE technique shows significant reduction in THD as the number of levels increased. Results for the output voltages and currents along with their frequency spectrum are shown and compared with traditional SPWM.
Volume: 12
Issue: 1
Page: 314-324
Publish at: 2021-03-01

The correlation between self-efficacy and peer interaction towards students’ employability in vocational high school

10.11591/ijere.v10i1.20573
Fatwa Tentama , Muhammad Zulfikar Nur
Employability is an important factor that can determine the quality of prospective graduates, especially in vocational high schools. Therefore, vocational high schools, as one of the educational institutions that prepare workforce resources, need to pay attention to factors that can increase their students' employability. This study aims to empirically examine the role of self-efficacy and the peer interaction on student employability. The subjects of this study were 132 students at Vocational High School Muhammadiyah Prambanan. The data were collected through an employability scale, a self-efficacy scale, and a peer interaction scale. The data were then analyzed with multiple linear regression techniques. The results showed that: 1) Simultaneously, there was a very significant role that self-efficacy and peer interaction have on employability with p=0.000 (p<0.01); 2) Partially, there was also a very significant role that self-efficacy has on employability with p=0.000 (p<0.01); 3) Peer interaction also had a partially significant role on employability with p=0.001 (p<0.01). Both self-efficacy and peer interaction simultaneously contributed 40.8% to employability, but self-efficacy had a more dominant role (26.7%) than peer interactions (14.1%).
Volume: 10
Issue: 1
Page: 8-15
Publish at: 2021-03-01

Optimal placement of facts devices to reduce power system losses using evolutionary algorithm

10.11591/ijeecs.v21.i3.pp1271-1278
Mahmood Khalid Zarkani , Ahmed Sahib Tukkee , Mohammed Jasim Alali
The rapid and enormous growths of the power electronics industries have made the flexible AC transmission system (FACTS) devices efficient and viable for utility application to increase power system operation controllability as well as flexibility. This research work presents the application of an evolutionary algorithm namely differential evolution (DE) approach to optimize the location and size of three main types of FACTS devices in order to minimize the power system losses as well as improving the network voltage profile. The utilized system has been reactively loaded beginning from the base to 150% and the system performance is analyzed with and without FACTS devices in order to confirm its importance within the power system. Thyristor controlled series capacitor (TCSC), unified power flow controller (UPFC) and static var compensator (SVC) are used in this research work to monitor the active and reactive power of the carried out system. The adopted algorithm has been examined on IEEE 30-bus test system. The obtained research findings are given with appropriate discussion and considered as quite encouraging that will be valuable in electrical grid restructuring.
Volume: 21
Issue: 3
Page: 1271-1278
Publish at: 2021-03-01
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