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29,922 Article Results

PMU-Based Transmission Line Parameter Identification at China Southern Power Grid

10.11591/ijape.v3.i3.pp190-198
Zhou Huafeng , Zhao Xuanyu , Shi Di , Zhao Huashi , Jing Chaoyang
China Southern Power Grid Company (CSG) recently developed and implemented an online PMU-based transmission line (TL) parameter identification system (TPIS). Traditionally, TL parameters are calculated based on transmission tower geometries, conductor dimension, estimates of line length, conductor sags, etc. These parameters only approximate the effect of conductor sag and ignore the dependence of impedance parameters on temperature variation. Recent development in PMU technology has made it possible to calculate TL parameters accurately. The challenges are that such application requires highly accurate PMU data while the accuracy of PMU measurements under different working/system conditions can be uncertain. With a large number of PMUs widely installed in its system, CSG plans to improve and update the EMS database using the newly developed TPIS. TPIS provides an innovative yet practical problem formulation and solution for TL parameter identification. In addition, it proposes a new metric that can be used to determine the credibility of the calculated parameters, which is missing in the literature. This paper discusses the methodologies, challenges, as well as implementation issues noticed during the development of TPIS.
Volume: 3
Issue: 3
Page: 190-198
Publish at: 2014-12-01

Clustering Algorithm Combined with Hill Climbing for Classification of Remote Sensing Image

https://ijece.iaescore.com/index.php/IJECE/article/view/5510
B.Sai Chandana , K. Srinivas , R. Kiran Kumar
Clustering is an unsupervised classification method widely used for classification of remote sensing images.  As the spatial resolution of remote sensing images getting higher and higher, the complex structure is the simple objects becomes obvious, which makes the classification algorithm based on pixels being losing their advantages. In this paper, four different clustering algorithms such as K-means, Moving K-means, Fuzzy K-means and Fuzzy Moving K-means are used for classification of remote sensing images. In all the traditional clustering algorithms, number of clusters and initial centroids are randomly selected and often specified by the user. In this paper, a hill climbing algorithm for the histogram of the input image will generate the number of clusters and initial centroids required for clustering.   It overcomes the shortage of random initialization in traditional clustering and achieves high computational speed by reducing the number of iterations. The experimental results show that Fuzzy Moving K-means has classified the remote sensing image more accurately than other three algorithms.DOI:http://dx.doi.org/10.11591/ijece.v4i6.6608
Volume: 4
Issue: 6
Page: 923-930
Publish at: 2014-12-01

An Application of Ulam-Hyers Stability in DC Motors

10.11591/ijape.v3.i3.pp149-156
Abasalt Bodaghi , Naser Pargali
In this paper, a generalization to nonlinear systems is proposed and applied to the motor dynamic, rotor model and stator model in DC motor equation. We argue that Ulam-Hyers stability concept is quite significant in design problems and in design analysis for the class of DC motor’s parameters. We prove the stability of nonlinear partial differential equation by using Banach’s contraction principle. As an application, the Ulam-Hyers stability of DC motor dynamics equations is investigated. To the best of our knowledge this is the first time Ulam-Hyers stability is considered from the applications point of view.
Volume: 3
Issue: 3
Page: 149-156
Publish at: 2014-12-01

Enhancing Photoelectric Conversion Efficiency of Solar Panel by Water Cooling

10.11591/ijape.v3.i3.pp199-204
M Mohamed Musthafa
Photovoltaic solar cell generates electricity by receiving solar irradiance. The electrical efficiency of photovoltaic (PV) cell is adversely affected by the significant increase of cell operating temperature during absorption of solar radiation. This undesirable effect can be partially avoided by cooling the back side of the photovoltaic panel using water absorption sponge which  was fixed on of PV panel and maintain wet condition by circulation of drop by drop water. The objective of the present work is to reduce the temperature of  the solar cell in order to increase its electrical efficiency.  Experiments were performed with and without water cooling. A linear trend between the efficiency and temperature was found. Without cooling, the temperature of the panel was high and solar cells were achieved an efficiency of 8–9%. However, when the panel was operated under water cooling condition, the temperature dropped maximally by 40C leading to an increase in efficiency of solar cells by 12%.
Volume: 3
Issue: 3
Page: 199-204
Publish at: 2014-12-01

The Automatic Recognition of Large Ball Valve Sealing Bolt Based on Digital Image

10.11591/ijeecs.v12.i12.pp8152-8160
Song Qingjun , Xiao Xingming , Jiang Haiyan , Zhao Xieguang
In this paper, we adopted the area filling method of the mathematical morphology to fill the holes of the nut. In addition, the bimodal method and multi-threshold method were combined for the image segmentation. Furthermore, the image edge was detected by mathematical morphology algorithm. Finally, the angle between the bolt and manipulator was calculated using the rotation conversion matrix. With the systematic error and correlation coefficient, the calculated angle was verified. Experimental results show that the method can protect the edge integrity of the nut image, with fast processing speed and strong anti-noise ability. The work in this paper provides a theoretical basis for the automatic recognition in the large ball valve sealing bolt system.
Volume: 12
Issue: 12
Page: 8152-8160
Publish at: 2014-12-01

Knowledge Management System for Zakat

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3955
Aulia Rahman Nasution , Irman Hermadi , Wisnu Ananta K. , Irfan Syauqi B.
Zakat is one of the Islamic pillars that has strategic contribution to the society. Zakat is one of the  Muslim obligation. It is also a form of social solidarity. The collaborative research conducted by Badan Amil Zakat Nasional (BAZNas) and Institut Pertanian Bogor (IPB) estimated the potential of zakat collection in Indonesia could reach about Rp 217 trillion every year that has not been achieved yet. Researchers and practitioners have advised to implement a Knowledge Management System (KMS) to optimize the collection and BAZNas’s objectives. The objective of this research is to develop web-based Zakat Knowledge Management System (ZKMS). The KMS development methodology is done with using Knowledge Management System Life Cycle (KMSLC). Knowledge has been captured from experts consisting of practitioners and scientists from BAZNas of Bogor City, muzakki, documents, books and journals. ZKMS was developed using ASP.NET framework, C# programming language and MySQL database management system. The system has menu that are user, zakat knowledge, questions and answers with experts, interaction between members, about us, profiles and knowledge sources. This system is designed be user friendly to get, know, make, share, store and disseminate actual and contemporary of zakat knowledge. http://dx.doi.org/10.11591/telkomnika.v12i12.6842 
Volume: 12
Issue: 12
Page: 8349-8356
Publish at: 2014-12-01

Improving Light-Load Efficiency by Eliminating Interaction Effect in the Grid Connected Doubly-Fed Induction Generator

10.11591/ijape.v3.i3.pp157-165
Seyed Esmaeel Mirhosseini Niri , Abdolhossain Tahani , Mohammad Yazdani-Asrami , S. Asghar Gholamian
A wind turbine equipped with doubly-fed induction generator (DFIG) is used in wind power plant industry. This paper studies the maximum power extraction of DFIG via evaluation of state-space equations in closed loop control condition for improving light-load efficiency. The DFIG state-space equations have been considered in the form of a multi-input- multi output (MIMO) system. Also, the tracing table has been used to determine the speed which the generated power will be proportional to the maximum load. The tracing table input is the generator speed, and its output is the optimum active power that has been considered as the reference power of the active power control system of the convertor. A controller is presented for the tracing table and the extracted power is able to follow the reference power with minimum ripple. Then, the results are compared with the single-input and single-output (SISO) case, for the values up to 0.2 times of the rated load. Therefore, in MIMO modeling, in the case that the DFIG connected to the grid, by eliminating the interaction effect, the efficiency in light-load can be increased.
Volume: 3
Issue: 3
Page: 157-165
Publish at: 2014-12-01

Application of Chaotic Particle Swarm Optimization in Wavelet Neural Network

10.12928/telkomnika.v12i4.533
Cuijie; Tianjin University of Finance and Economics Zhao , Guozhen; Bohai Professional and Technical College Wang
Currently, the method of optimizing the wavelet neural network with particle swarm plays a certain role in improving the convergence speed and accuracy; however, it is not a good solution for problems of turning into local extrema and poor global search ability. To solve these problems, this paper, based on the particle swarm optimization, puts forward an improved method, which is introducing the chaos mechanism into the algorithm of chaotic particle swarm optimization. Through a series of comparative simulation experiments, it proves that applying this algorithm to optimize the wavelet neural network can successfully solve the problems of turning into local extrema, and improve the convergence speed of the network, in the meantime, reduce the output error and improve the search ability of the algorithm. In general, it helps a lot to improve the overall performance of the wavelet neural network.
Volume: 12
Issue: 4
Page: 997-1004
Publish at: 2014-12-01

A New Algorithm for Detecting Local Community Based on Random Walk

10.12928/telkomnika.v12i4.438
Yueping; Shenzhen Polytechnic Li , Weikun; Shenzhen Institute of Information Technology Zheng
This paper presents one new algorithm for local community discovery. It employs a new vertex selection strategy which considers not only the boundary structure of candidate local community but also the probability which the investigated vertex will return to the candidate local community. A local random walk is adopted to compute this return probability which does not require the global information. We choose four algorithms for comparison which are the best ones existed by far. For better evaluation, the datasets include not only the computer generated graphs in standard benchmark but also the real-world networks which are classical ones in global community discovery. The experimental results show our algorithm outperforms the other ones on the computer generated graphs. The performance of our algorithm is approximately the same with the algorithm proposed by Luo, Wang and Promislow on real-world networks.
Volume: 12
Issue: 4
Page: 1005-1016
Publish at: 2014-12-01

Dynamic DEMATEL Group Decision Approach Based on Intuitionistic Fuzzy Number

10.12928/telkomnika.v12i4.787
Hui; University of Science and Technology Xie , Wanchun; University of Science and Technology Duan , Yonghe; University of Science and Technology Sun , Yuanwei; University of Science and Technology Du
With respect to the problems of aggregation about group experts’ information and dynamic decision in DEMATEL(decision making trial and evaluation laboratory), a dynamic DEMATEL group expert decision-making method on intuitionistic fuzzy number(IFN) is presented. Firstly using IFN instead of original point estimates to reflect the experts’ preference, the group experts’ information are integrated horizontally at each period. Then the aggregation information at different periods are aggregated vertically again by dynamic intuitionistic fuzzy weighted averaging (DIFWA) operator so as to obtain the dynamic intuitionistic fuzzy DEMATEL total relation matrix. Thirdly, through the analysis of center and reason degree, the positions of the various factors in the system are clear and definite, and the inner structure of system has been revealed. Finally, the feasibility and practicability of the proposed method is shown through an illustrative example of a process of course selection in a school.
Volume: 12
Issue: 4
Page: 1064-1072
Publish at: 2014-12-01

Optical Tomography Sensor Configuration for Estimating the Turbidity Level of Water

10.11591/ijict.v3i3.pp153-161
Mohd Taufiq Mohd Khairi , Sallehuddin Ibrahim , Mohd Amri Md Yunus , Mohd Najmi Mohd Sulaiman , Mahdi Faramarzi
This paper presents an investigation on an optical sensor configuration to estimate the turbidity level in a sample of water based on tomography technique. The optical sensors consist of infrared light - emitting diodes (LED) as transmitters and photodiodes as the receivers where the projections of the sensors are designed in fan beam mode. The promising results obtained from the analysis of light path detection demonstrated the accuracy of the proposed technique in estimating the turbidity level of water. The approach has potential to contribute and utilize for monitoring the quality level of water in water treatment industries.
Volume: 3
Issue: 3
Page: 153-161
Publish at: 2014-12-01

Review of Local Descriptor in RGB-D Object Recognition

10.12928/telkomnika.v12i4.388
Ema; Bandung Institute of Technology Rachmawati , Iping Supriana; Bandung Institute of Technology Suwardi , Masayu Leylia; Bandung Institute of Technology Khodra
The emergence of an RGB-D (Red-Green-Blue-Depth) sensor which is capable of providing depth and RGB images gives hope to the computer vision community. Moreover, the use of local features began to increase over the last few years and has shown impressive results, especially in the field of object recognition. This article attempts to provide a survey of the recent technical achievements in this area of research. We review the use of local descriptors as the feature representation which is extracted from RGB-D images, in instances and category-level object recognition. We also highlight the involvement of depth images and how they can be combined with RGB images in constructing a local descriptor. Three different approaches are used in involving depth images into compact feature representation, that is classical approach using distribution based, kernel-trick, and feature learning. In this article, we show that the involvement of depth data successfully improves the accuracy of object recognition.
Volume: 12
Issue: 4
Page: 1132-1141
Publish at: 2014-12-01

A Review of Parabolic Dish-Stirling Engine System Based on Concentrating Solar Power

10.12928/telkomnika.v12i4.1132
Liaw Geok; Universiti Teknikal Malaysia Melaka Pheng , Rosnani; Universiti Teknikal Malaysia Melaka Affandi , Mohd Ruddin; Universiti Teknikal Malaysia Melaka Ab Ghani , Chin Kim; Universiti Teknikal Malaysia Melaka Gan , Zanariah; Universiti Teknikal Malaysia Melaka Jano , Tole; Universitas Ahmad Dahlan Sutikno
A solar thermal technology which is also known as concentrating solar power (CSP) uses thermal energy from the sun to generate electricity. The electricity generation from solar thermal can be produced with four technologies of concentrating solar systems which are parabolic trough, linear Fresnel reflector, solar tower, and parabolic dish-Stirling engine system. This paper reviews the parabolic dish-stirling based on CSP technology by taking into account the performance, the global performance, site for parabolic dish and levelized cost of energy (LCOE). Generally, the parabolic dish applications have barriers in terms of the technology and the high capital cost compared to the others CSP technologies. 
Volume: 12
Issue: 4
Page: 1142-1152
Publish at: 2014-12-01

Sparsity Properties of Compressive Video Sampling Generated by Coefficient Thresholding

10.12928/telkomnika.v12i4.296
Ida Wahidah; Institut Teknologi Bandung Hamzah , Tati Latifah; Institut Teknologi Bandung R. Mengko , Andriyan; Institut Teknologi Bandung B. Suksmono , Hendrawan; Institut Teknologi Bandung Hendrawan
We study the compressive sampling (CS) and its application in video encoding framework. The video input is firstly transformed into suitable domain in order to achieve sparser configuration of coefficients. Then, we apply coefficient thresholding to classify which frames to be sampled compressively or conventionally. For frames chosen to undergo compressive sampling, the coefficient vectors will be projected into smaller vectors using random measurement matrix. As CS requires two main conditions, i.e. sparsity and matrix incoherence, this research is emphasized on the enhancement of sparsity property of the input signal. It was empirically proven that the sparsity enhancement could be reached by applying motion compensation and thresholding to the non-significant coefficient count. At the decoder side, the reconstruction algorithm can employ basis pursuit or L1 minimization algorithm.
Volume: 12
Issue: 4
Page: 897-904
Publish at: 2014-12-01

A Novel Technique for Vector Control of Single-Phase Induction Motors Based on Rotor Field-Oriented Control

10.11591/ijeecs.v12.i12.pp8104-8113
Mohammad Jannati , Sajad Abdollahzadeh Anbaran , Nik Rumzi Nik Idris , Mohd Junaidi Abdul Aziz
Due to asymmetrical characteristics of single-phase IMs, conventional vector control methods for three-phase IMs cannot be directly applied to single-phase IMs. This study aims to improve performance of the single-phase IMs drive system. Hence, a novel control approach based on Rotor Field-Oriented control (RFOC) was developed for single-phase IMs. For this purpose, transformation matrices are applied to the machine equations. It is shown by applying these transformation matrices to the unbalanced equations of single-phase IM results in set of balanced equations with backward and forward components. Therefore, by some modifications in the conventional RFOC method for three-phase IM, vector control of single-phase IM can be done. The proposed method demonstrates reasonably good speed and torque responses with satisfactory tracking capability. It is shown the effect of using this supposition is reflected on the motor torque and hence speed oscillations. Due to good tracking capability of proposed drive system, this control technique can be a well-suited candidate for application where precise move of IM in required such as cutting, knurling and deformation processes.
Volume: 12
Issue: 12
Page: 8104-8113
Publish at: 2014-12-01
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