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29,758 Article Results

Risk assessment for ancillary services

10.11591/ijece.v9i3.pp1561-1568
Omer Hadzic , Smajo Bisanovic
The power trading and ancillary services provision comprise technical and financial risks and therefore require a structured risk management. Focus in this paper is on financial risk management that is important for the system operator faces when providing and using ancillary services for balancing of power system. Risk on ancillary services portfolio is modeled through value at risk and conditional value at risk measures. The application of these risk measures in power system is given in detail to show how to using the risk concept in practice. Conditional value at risk optimization is analysed in the context of portfolio selection and how to apply this optimization for hedging a portfolio consisting of different types of ancillary services.
Volume: 9
Issue: 3
Page: 1561-1568
Publish at: 2019-06-01

Testing embedded system through optimal mining technique (OMT) based on multi-input domain

10.11591/ijece.v9i3.pp2141-2151
J. K. R. Sastry , M. Lakshmi Prasad
Testing embedded systems must be done carefully particularly in the significant regions of the embedded systems. Inputs from an embedded system can happen in multiple order and many relationships can exist among the input sequences. Consideration of the sequences and the relationships among the sequences is one of the most important considerations that must be tested to find the expected behavior of the embedded systems. On the other hand combinatorial approaches help determining fewer test cases that are quite enough to test the embedded systems exhaustively. In this paper, an Optimal Mining Technique that considers multi-input domain which is based on built-in combinatorial approaches has been presented. The method exploits multi-input sequences and the relationships that exist among multi-input vectors. The technique has been used for testing an embedded system that monitors and controls the temperature within the Nuclear reactors.
Volume: 9
Issue: 3
Page: 2141-2151
Publish at: 2019-06-01

Wind turbine doubly-fed asynchronous machine diagnosis defects using stator and rotor currents lissajous curves

10.11591/ijpeds.v10.i2.pp961-970
Fatima El Hammouchi , L. El Menzhi , A. Saad , Y. Ihedrane , B. Bossoufi
In the current paper, a method is developed to diagnose potential electrical defects attacking doubly fed induction generator in Moroccan wind turbines firms. The proposed method is based on stator and rotor currents Lissajous curves analysis. Firstly, we focus on modeling of a non-defected wind conversion systems based on mathematic model created in Matlab Simulink which is able to reflect the behaviour of the wind turbine during asynchronous generator defects-free operation. After that, an indirect stator field vector oriented control is applied to obtain the wind system performance. Finally, stator and rotor currents Lissajous curves are analyzed in case of a non-defected generator that represents the system reference curves for diagnosing defects. The simulations had been realized by Matlab Simulink. Their results showed the effectiveness of the proposed method.
Volume: 10
Issue: 2
Page: 961-970
Publish at: 2019-06-01

Flood disaster indicator of water level monitoring system

10.11591/ijece.v9i3.pp1694-1699
Wan Haszerila Wan Hassan , Aiman Zakwan Jidin , Siti Asma Che Aziz , Norain Rahim
The early warning systems for flood management have been developed rapidly with the growth of technologies. These system help to alert people early with the used of Short Message Service (SMS) via Global System for Mobile Communications (GSM). This paper presents a simple, portable and low cost of early warning system using Arduino board, which is used to control the whole system and GSM shields to send the data. System has been designed and implemented based on two components which is hardware and software. The model determines the water level using float switch sensors, then it analyzes the collected data and determine the type of danger present. The detected level is translated into an alert message and sent to the user. The GSM network is used to connect the overall system units via SMS.
Volume: 9
Issue: 3
Page: 1694-1699
Publish at: 2019-06-01

The telecom value chain, opportunities and revenues created by the nigerian telecom boom

10.11591/ijece.v9i3.pp2018-2024
Nsikan Nkordeh , Uzairue Stanley Idiake , Ibinabo Bob-Manuel , Francis Anyasi
In Nigeria today, we face a serious economic challenge which is as a result of our swindling primary source of revenue (oil), there is fear amongst our economists which is can Nigeria bounce back to what she once was? Can there be an alternative source to serve as a buffer to what we already have. This study aims to bring to prime focus, an industry which has begun blooming in the background. Despite the publicity and popularity enjoyed by today’s telecom giants in the country, there is very little knowledge pertaining to the tremendous impact that it has had directly or indirectly on our economy over the years. Since the liberalization of the telecom industry that brought about the involvement of private investors into the sector, the opportunities and revenues generated has brought about a tremendous effect on the economy. The telecom sector is only second after the oil and gas industry in the amount of finance it contributes to the federal account. This paper discusses some of the value chains, opportunities, revenue that the telecom industry has brought to Nigeria. It uses data obtained from relevant authorities.
Volume: 9
Issue: 3
Page: 2018-2024
Publish at: 2019-06-01

Image watermarking based on integer wavelet transform-singular value decomposition with variance pixels

10.11591/ijece.v9i3.pp2185-2195
Ferda Ernawan , Dhani Ariatmanto
With the era of rapid technology in multimedia, the copyright protection is very important to preserve an ownership of multimedia data. This paper proposes an image watermarking scheme based on Integer Wavelet Transform (IWT) and Singular Value Decomposition (SVD). The binary watermark is scrambled by Arnold transform before embedding watermark. Embedding locations are determined by using variance pixels. Selected blocks with the lowest variance pixels are transformed by IWT, thus the LL sub-band of 8×8 IWT is computed by using SVD. The orthogonal U matrix component of U3,1 and U4,1 are modified using certain rules by considering the watermark bits and an optimal threshold. This research reveals an optimal threshold value based on the trade-off between robustness and imperceptibility of watermarked image. In order to measure the watermarking performance, the proposed scheme is tested under various attacks. The experimental results indicate that our scheme achieves higher robustness than other scheme under different types of attack.
Volume: 9
Issue: 3
Page: 2185-2195
Publish at: 2019-06-01

Pre-service teachers’ web pedagogical content knowledge and online information searching strategies

10.11591/ijere.v8i2.18771
Güler Tuluk , İbrahim Kepceoglu
This study aimed to investigate the relationship between pre-service teachers’ web pedagogical content knowledge and online information searching strategies. In accordance with the aim, the correlational comparative survey method is used. The participants of the study are 220 university students from a faculty of education of a state university. The data of the study is gathered by Turkish versions of “Teachers’ Self-Efficacy toward the Web Pedagogical Content Knowledge Scale” and “Online Information Searching Strategy Inventory”. Canonical correlation analysis is used to determine the relationship between these two scales. As a result of the study, 17.3% common variance is determined between web pedagogical content knowledge and online information searching strategies.
Volume: 8
Issue: 2
Page: 229-236
Publish at: 2019-06-01

Exploring obstacles in language learning: Prospective primary school teacher in Indonesia

10.11591/ijere.v8i2.16700
Asrial Asrial , Syahrial Syahrial , Dwi Agus Kurniawan , May Subandiyo , Nur Amalina
In the implementation of educational practices, Indonesian is used as the language of instruction. Teacher candidates are prepared to have language competence as their knowledge in carrying out classroom learning. Important language competence is owned by a prospective elementary school teacher to facilitate communication with students and design learning about language. In an effort to improve material understanding and mastery of good language competence, prospective teachers in Primary School Teacher Education have constraints in the learning process in tertiary institutions that are identified based on 9 indicators. These indicators consist of curriculum, practicum activities materials/tools, books/modules, initial abilities of prospective teachers, learning resources from outdoor learning, learning resources from outdoor language learning, learning resources from indoor learning, learning environments, motivating teacher candidates, and the ability to judge yourself. This study uses a qualitative research approach. This study aims to analyze the constraints students face in Indonesian language competence. The sample in this study were students in Primary School Teacher Education with a total of 30 respondents. Data collection using interview and documentation techniques.
Volume: 8
Issue: 2
Page: 249-254
Publish at: 2019-06-01

Embedded real-time system for detecting leakage of the gas used in iraqi kitchens

10.11591/ijeecs.v14.i3.pp1171-1176
Husam Kareem
A major issue that happens in kitchens of houses and/or restaurants is the leakage of gas used as a fuel for cooker stove, which is commonly referred to as LPG (liquefied petroleum gas). LPG leakage may lead to a serious fire or even a deadly explosion that might affect the surrounding people. A substantial solution to avoid such disasters is by stopping its main cause. Therefore designing a device capable of monitoring and detecting such gases can minimize the dangerous and unwanted incidents by LPG leakage. This paper introduces a low cost and energy efficient real-time monitoring system that able to sense different dangerous gases, specifically those used for stove cooker. This system considers the pros of the previously introduced systems and fixes the cons available in those systems. In addition, the manufacturing cost has been taken into consideration. If the system senses any type of LPG gas (there is a gas leakage), it will react by making three different actions. It will make an alert sound to notify the people around the leakage place, send an SMS to two cell phones, and show, on an LCD screen, the leakage location.
Volume: 14
Issue: 3
Page: 1171-1176
Publish at: 2019-06-01

Reengineering framework for open source software using decision tree approach

10.11591/ijece.v9i3.pp2041-2048
Jaswinder Singh , Kanwalvir Singh , Jaiteg Singh
A Software engineering is an approach to software development. Once software gets developed and delivered, it needs maintenance. Changes in software incur due to new requirements of the end-user, identification of bug in software or failure to achieve system objective. It has been observed that successive maintenance in the developed software reduces software quality and degrades the performance of software system. Reengineering is an approach of retaining the software quality and improving maintainability of the software system. But the question arises “when to reengineer the software”. The paper proposed a framework for software reengineering process using decision tree approach which helps decision makers to decide whether to maintain or reengineer the software systems.
Volume: 9
Issue: 3
Page: 2041-2048
Publish at: 2019-06-01

Development of square wave inverter using DC/DC boost converter

10.11591/ijpeds.v10.i2.pp636-644
M. Z. Aihsan , N. I. Ahmad , W. A. Mustafa , N. A. Rahman , J. A. Soo
This paper proposes an alternative topology of an inverter to the existing topologies available in the market. A prototype is intended with the purpose of investigates the possibility of designing an inverter using two Boost Converters. This project initialized with a series of simulations using Matlab in order to determine the feasibility of the proposed topology. The next step is the design and development of the proposed prototype where suitable electronics components are chosen based on the simulation result. A PIC microcontroller is used to control the proposed prototype where a control scheme is created based on the programming in the microcontroller. The performance of the proposed prototype has been verified to be optimum by several practical testing using different values of capacitor, inductor and duty cycle. Lastly, data and analysis are presented in a proper mannered way. In the end, this project intends to produce stepped-up square wave output voltage waveform by proper controlling of two Boost Converters.
Volume: 10
Issue: 2
Page: 636-644
Publish at: 2019-06-01

Data mining techniques application for prediction in OLAP cube

10.11591/ijece.v9i3.pp2094-2102
Asma Lamani , Brahim Erraha , Malika Elkyal , Abdallah Sair
Data warehouses represent collections of data organized to support a process of decision support, and provide an appropriate solution for managing large volumes of data. OLAP online analytics is a technology that complements data warehouses to make data usable and understandable by users, by providing tools for visualization, exploration, and navigation of data-cubes. On the other hand, data mining allows the extraction of knowledge from data with different methods of description, classification, explanation and prediction. As part of this work, we propose new ways to improve existing approaches in the process of decision support. In the continuity of the work treating the coupling between the online analysis and data mining to integrate prediction into OLAP, an approach based on automatic learning with Clustering is proposed in order to partition an initial data cube into dense sub-cubes that could serve as a learning set to build a prediction model. The technique of data mining by regression trees is then applied for each sub-cube to predict the value of a cell.
Volume: 9
Issue: 3
Page: 2094-2102
Publish at: 2019-06-01

Economical and efficient technique for a static localized maximum sun lux determination

10.11591/ijpeds.v10.i2.pp777-784
Ahmed H. Ali , Adel S. Nada , Ahmed S. Shalaby
Solar energy is one of the most promising renewable sources that is currently being used worldwide to contribute for meeting rising demands. In this paper solar irradiance measurement will experimentally carried out in two different regions in Egypt; Cairo and Luxor cities. This paper proposes a simple solar lux measurement using a light dependent resistor (LDR) with an arduino kit. This technique is based on two approaches which are coarse and fine maximum sun lux determination. This is based on the predetermined 260 vertical slop of the LDR. Coarse tuning determines one of the reach sun lux quarter (900) of horizontal quad. The fine tuning allocates the optimized 100 in which; the maximum sun lux can be obtained. The optimal values of sun lux were found between the (90o–180o) quarter. This study confirms that the narrow ten degrees (95o-105o) are the optimized static sun lux extraction for the two site field measurements. This novel technique can be used for locating the angle of best installations for the solar cell at which maximum solar energy can be extracted. 
Volume: 10
Issue: 2
Page: 777-784
Publish at: 2019-06-01

Adaptive resources assignment in OFDM-based cognitive radio systems

10.11591/ijece.v9i3.pp1935-1943
Shirin Razmi , Naser Parhizgar
Spectrum efficiency of orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) systems can be improved by adaptive resources allocation. In resources allocation, transmission resources such as modulation level and transmission power are adaptively assigned based on channel variations. The goal of this paper is maximize the total transmission rate of secondary user (SU). Hence, we investigate adaptive power and modulation allocation to achieve this purpose. For power allocation, we investigate optimal and conventional methods and then introduce a novel suboptimal algorithm to calculate the transmission power of each subcarrier. In addition, for adaptive modulation, we consider two kinds of modulations including multi-quadrature amplitude modulation (MQAM) and multi-phase-shift keying (MPSK). Also, simulation results are indicated the performance of our algorithm.
Volume: 9
Issue: 3
Page: 1935-1943
Publish at: 2019-06-01

PID controller using rapid control prototyping techniques

10.11591/ijece.v9i3.pp1645-1655
Odair A. Trujillo , Nicolás Toro-García , Fredy E. Hoyos
To analyze the performance of the PID controller in a buck type converter implemented in real time. We begin by designing a continuous controller using the analytical method for calculating PIDs. Pulse width modulation is then used and bifurcation diagrams analyzed to reveal some problems of switching and sampling time. The model converter is then implemented with a PID controller in dSPACE. The experimental results provide detailed requirements of sampling frequency and switching speed, and show the performance of the PID controller. Converters are used in power generation solar systems and conmuted power sources for feed telecommunication devices, smart grids, and other applications.
Volume: 9
Issue: 3
Page: 1645-1655
Publish at: 2019-06-01
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