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27,404 Article Results

Design and Implementation of a Microcontroller Based Buck Boost Converter as a Smooth Starter for Permanent Magnet Motor

10.11591/ijeecs.v1.i3.pp566-574
S. Ravi , Vitaliy Mezhuyev , K. Iyswarya Annapoorani , P. Sukumar
This proposal proposes a DC/DC Buck Boost converter which has been used as a smooth starter for a DC Permanent Magnet Motor. In the existing system the DC/DC Buck Converter is used which provide the output less than the input Signal. Using buck converter it is difficult to increase the value of the input signal. Hence DC/DC Buck- Boost Converter used from which it is possible to get both the increased and decreased output from the given input. Previously pulse width modulation signals with respective to motor voltage is used. However they produce variations in the voltage and current of the motor. The above problem is overcome by using DC/DC Power converter. The proposed system with reduction in size, reduced ripples and increase in speed makes the system to operate at both low and high power applications. The proposed system results in higher efficiency, reduces the ripple content and the stress. The results are validated through MATLAB/Simulink and real time implementation.
Volume: 1
Issue: 3
Page: 566-574
Publish at: 2016-03-01

A Cellular Automata Modeling for Visualizing and Predicting Spreading Patterns of Dengue Fever

10.12928/telkomnika.v14i1.2404
Puspa Eosina; Bogor Agriculture University Hosen , Taufik; Bogor Agriculture University Djatna , Helda; University of Indonesia Khusun
A Cellular Automata (CA) model is used for visualizing and predicting spreading pattern of the disease. The main problem of this model is how to find a function that represents an update rule that changes the state of a cell in time steps affected by neighborhood. This research aims to develop visualization and prediction model of the spreading patterns of Dengue Hemorrhagic Fever. The contribution of our study is to introduce a new approach in defining a probabilistic function that represents CA transmission rule by employing Von Neumann neighborhood and the Hidden Markov Model (HMM). This study only considered an infective state which dedicated particular attention to the spatial distribution of infected areas. The infected data were devided into four categories and change the definition of a cell as an area. The evaluation was conducted by comparing the results of the proposed model to that of one yielded by a Susceptible-Infected-Recovered (SIR) model. The evaluation result showed that the CA model was capable of generating patterns that similar to the patterns generated by SIR models with a similarities value of 0.95.
Volume: 14
Issue: 1
Page: 228-237
Publish at: 2016-03-01

Analysis of Handover Trigger Scheme Based on Distance for LTE High-speed Railway Networks

10.12928/telkomnika.v14i1.2742
Rui; Beijing University of Posts and Telecommunications Zhang , Muqing; Beijing University of Posts and Telecommunications Wu , Yifan; Beijing University of Posts and Telecommunications Zhang
In high-speed railway environment, frequent handovers and high handover failure probability result in serious communication interruptions and call drops, which become pressing problem to be solved. Alternative reference point based handover scheme can be an applicative solution for high-speed rail. This paper analyzes the impact of handover location on the handover performance. And numerical analysis is utilized to give a method to determine the distance from the serving eNodeB and the adjacent one to the mobile terminal when handover is triggered. Handover failure probability is used as criteria for performance. Simulation results show that the proposed scheme has a better performance than typical event based scheme in high speed environment.
Volume: 14
Issue: 1
Page: 129-135
Publish at: 2016-03-01

A Simple Checking Algorithm with Perturb and Observe Maximum Power Point Tracking for Partially Shaded Photovoltaic System

10.12928/telkomnika.v14i1.1356
Rozana; Universiti Teknologi Malaysia Alik , Awang; Universiti Teknologi Malaysia Jusoh , Tole; Universitas Ahmad Dahlan Sutikno
This paper presents a simple checking algorithm for maximum power point tracking (MPPT) technique for Photovoltaic (PV) system using Perturb and Observe (P&O) algorithm. The main benefit of this checking algorithm is the simplicity and efficiency of the system whose duty cycle produced by the MPPT is smoother and changes faster according to maximum power point (MPP). This checking algorithm can determine the maximum power first before the P&O algorithm takes place to identify the voltage at MPP (VMPP), which is needed to calculate the duty cycle for the boost converter. To test the effectiveness of the algorithm, a simulation model of PV system has been carried out using MATLAB/Simulink under different level of irradiation; or in other words partially shaded condition of PV array. The results from the system using the proposed approach prove to have faster response and low ripple. Besides, the results are close to the desired outputs and exhibit an approximately 98.25% of the system efficiency. On the other hand, the system with conventional P&O MPPT seems to be unstable and has higher percentage of error. In summary, the proposed method is useful under varying level of irradiation with higher efficiency of the system.
Volume: 14
Issue: 1
Page: 14-20
Publish at: 2016-03-01

Carrier Aggregation Technique to Improve Capacity in LTE-Advanced Network

10.12928/telkomnika.v14i1.2668
Iskandar; Bandung Institute of Technology Iskandar , R.; Bandung Institute of Technology Galih
Carrier aggregation (CA) is a major feature in LTE-advanced technology that allows network provider to use more than one carrier simultaneously to increase capacity. CA uses two or more individual component carriers (CCs) of the same (intra-band) and different (inter-band) frequency bands. In this paper, we evaluate CA techniques with the test parameter using BLER and throughput inside the tested area of LTE network. The tested area is designed to represent most common environment in which LTE will be deployed. We use 30 MHz frequency bandwidth in the simulation to evaluate intra-band and inter-band CA technique performance. Two CCs is allocated for primary serving cell (PCell) and secondary serving cell (SCell). Simulation result shows for the downlink, BLER tend to increase, as the frequency configuration is increase. However, for the uplink BLER is zero. We found that for CA configuration with wider PCell bandwidth resulting better throughput. In CA intra-band, the throughput of non-contiguous CA is better than CA contiguous. Then in the inter-band CA, CC combination with a lower frequency produces higher throughput.
Volume: 14
Issue: 1
Page: 119-128
Publish at: 2016-03-01

Improving Multi-Document Summary Method Based on Sentence Distribution

10.12928/telkomnika.v14i1.2330
Aminul; Institut Teknologi Sepuluh Nopember Wahib , Agus Zainal; Institut Teknologi Sepuluh Nopember Arifin , Diana; Institut Teknologi Sepuluh Nopember Purwitasari
Automatic multi-document summaries had been developed by researchers. The method used to select sentences from the source document would determine the quality of the summary result. One of the most popular methods used in weighting sentences was by calculating the frequency of occurrence of words forming the sentences. However, choosing sentences with that method could lead to a chosen sentence which didn't represent the content of the source document optimally. This was because the weighting of sentences was only measured by using the number of occurrences of words. This study proposed a new strategy of weighting sentences based on sentences distribution to choose the most important sentences which paid much attention to the elements of sentences that were formed as a distribution of words. This method of sentence distribution enables the extraction of an important sentence in multi-document summarization which served as a strategy to improve the quality of sentence summaries. In that respect were three concepts used in this study: (1) clustering sentences with similarity based histogram clustering, (2) ordering cluster by cluster importance and (3) selection of important sentence by sentence distribution. Results of experiments showed that the proposed method had a better performance when compared with SIDeKiCK and LIGI methods. Results of ROUGE-1 showed the proposed method increasing 3% compared with the SIDeKiCK method and increasing 5.1% compared with LIGI method. Results of ROUGE-2 proposed method increase 13.7% compared with the SIDeKiCK and increase 14.4% compared with LIGI method.
Volume: 14
Issue: 1
Page: 286-293
Publish at: 2016-03-01

Certificateless Signature Scheme Based on Rabin Algorithm and Discrete Logarithm

10.12928/telkomnika.v14i1.2919
Xiangjun; Zhengzhou University of Light Industry Xin , Chaoyang; Zhengzhou University of Light Industry Li
Certificateless signature can effectively immue the key escrow problem in the identity-based signature scheme. But the security of the most certificateless signatures usually depends on only one mathematical hard problem, which makes the signature vulnerable when the underlying hard problem has been broken. In order to strengthen the security, in this paper, a certificateless signature whose security depends on two mathematical hard problems, discrete logarithm and factoring problems, is proposed. Then, the proposed certificateless signature can be proved secure in the random oracle, and only both of the two mathematical hard problems are solved, can the proposed signature be broken. As a consequence, the proposed certificateless signature is more secure than the previous signatures. On the other hand, with the pre-computation of the exponential modular computation, it will save more time in the signature signing phase. And compared with the other schemes of this kind, the proposed scheme is more efficient.
Volume: 14
Issue: 1
Page: 335-341
Publish at: 2016-03-01

Morphological Feature Extraction of Jabon’s Leaf Seedling Pathogen using Microscopic Image

10.12928/telkomnika.v14i1.2486
Melly Br; Bogor Agricultural University Bangun , Yeni; Bogor Agricultural University Herdiyeni , Elis Nina; Bogor Agricultural University Herliyana
This research aims to analyze morphological techniques for feature extraction of Jabon’s leaf seedling pathogen using digital microscopic image. The kinds of the pathogen were Curvularia sp., Colletotrichum sp., and Fusarium sp.. Pathogens or causes of disease were identified manually based on macroscopic and microscopic observation of morphological characters. Morphological characters describe the characteristics of shape, color and size of a pathogen structure. We focused on shape feature by using the morphological techniques to feature extraction. The morphology features extraction used were area, perimeter, convex area, convex perimeter, compactness, solidity, convexity, and roundness. The methodologies were acquisition, preprocessing, features extraction and data analysis for derivative features. With features extraction, we got the pattern that described each pathogen for pathogen identification. From the experimental result showed that compactness and roundness feature were able to differentiate each pathogen due to that the characteristics of each pathogen class were separated.
Volume: 14
Issue: 1
Page: 254-261
Publish at: 2016-03-01

A Novel Scheme of Speech Enhancement using Power Spectral Subtraction - Multi-Layer Perceptron Network

10.12928/telkomnika.v14i1.2021
Budiman P.A.; Indonesian Institute of Sciences Rohman , Ken; Indonesian Institute of Sciences Paramayudha , Asep Yudi; Indonesian Institute of Sciences Hercuadi
A novel method for eliminating noise from a noised speech signal in order to improve its quality using combined power spectral subtraction and multi-layer perceptron network is presented in this paper. Firstly, the contaminated speech signal was processed by spectral subtraction to enhance the clean speech signal. Then, the signal was processed by a neural network using the spectral subtraction parameters and result of estimated speech signal in order to improve its signal quality and intelligibility. The artificial neural network used was multi-layer perceptron network consisted of three layers with six input and one output. The neural network was trained with three speech signals contaminated with two level white gaussian noises in SNR including 0 dB and 30dB. The designed speech enhancement was examined with ten noised speech signals. Based on the experiments, the improvement of signal quality SNR was up to 7 dB when the signal quality input was 0dB. Then, based on the PESQ score, the proposed method can improve up to 0.4 from its origin value. Those experiment results show that the proposed method is capable to improve both the signal quality and intelligibility better than the original power spectral subtraction.
Volume: 14
Issue: 1
Page: 181-186
Publish at: 2016-03-01

A Coherent Framework for Understanding the Success of an Information System Project

10.12928/telkomnika.v14i1.2711
Syopiansyah Jaya; Syarif Hidayatullah State Islamic University Jakarta Putra , A'ang; Syarif Hidayatullah State Islamic University Jakarta Subiyakto , Abd. Rahman; International Islamic University Malaysia Ahlan , Mira; International Islamic University Malaysia Kartiwi
This paper elucidates the sequential revisions of an information system (IS) project framework across the research model development and its examinations. The authors adopted, adapted, and combined five concepts of the project management discipline and the information processing theory to revise the framework. Besides the use of this multi-dimensional perspective, the authors were also succeeded to present an interrelation between the framework and the examined model within a coherent representation. It was one of the essential points of this model development study, in particular for presenting the research focus. It may be trivial issue for the experts in the research fields, but the coherent illustration is one of the critical issues in the validity measurement of a model, whereas the inexpert ones may need a guideline to represent the interrelationship. Such points became the main contribution of this study to fill the gap in the literatures, particularly in the lack of comprehensive detail of a research model development.
Volume: 14
Issue: 1
Page: 302-308
Publish at: 2016-03-01

Impact of Extrinsic and Intrinsic Motivation Element to People Knowledge Sharing Behavior at Virtual Communities of Practices in Indonesia

10.11591/ijeecs.v1.i3.pp619-626
Setiawan Assegaff , Kurniabudi Kurniabudi , Erick Fernando
One of critical challenge in knowledge management success is to motivate people share their knowledge to others. Prior’s research reveals that motivation as primary driver for people to perform knowledge sharing. Previous study also indicated people influenced by internal (intrinsic) and external (extrinsic) motivation when perform the knowledge sharing. The aim of this article is to investigate and explores how the elements of extrinsic and intrinsic motivation contribute to people intention in perform knowledge sharing in virtual communities. Moreover this study would confirm and understand how this knowledge sharing behavior occurs in Indonesia Context. Many literatures argue that different culture context would produce different of people belief and behavior. This study conducts a survey in a formal virtual community of practices members in one Indonesia Company. Two hundred and four respondents participated in this study. Data was analysis using SEM with Smart PLS Software. This study found that both of those motivations (intrinsic and extrinsic) are positively influences behavior of people knowledge sharing in formal Virtual Communities of Practices. In advance this studies indicate that extrinsic motivation is major motivation element that influencing people in perform knowledge sharing.
Volume: 1
Issue: 3
Page: 619-626
Publish at: 2016-03-01

Active Disturbance Rejection Control of Thermal Power Unit Coordinated System based on Frequency Domain Analysis

10.12928/telkomnika.v14i1.2746
Ruiqing; Agricultural University of Hebei Zhang , Liangyu; North China Electric Power University Ma , Yongguang; North China Electric Power University Ma , Yang; Agricultural University of Hebei Liang , Liwei; Agricultural University of Hebei Geng
For the multi-input and multi-output, strong-coupling nonlinear features of coordinated system for thermal power unit, it is difficult for traditional PID coordinated control scheme to meet the power grid demand which often participates in peak regulation and frequency modulation. In this paper, Inverse Nyquist array is employed to carry out frequency domain analysis of the plant model. Then Pseudo diagonalization is used to design the static decoupling compensation matrix of the system. Above on these, the linear active disturbance rejection controller of every channel in coordinated system can be designed repectively. Dynamic coupling and system unknown parts are observed by extended state observer of ADRC and is compensated to the system in time. The simulation tests show that the disturbance rejection results of the load and the main steam pressure for the coordinated control system under LADRC is better than that of PID control.
Volume: 14
Issue: 1
Page: 162-170
Publish at: 2016-03-01

Detection and Prediction of Peatland Cover Changes Using Support Vector Machine and Markov Chain Model

10.12928/telkomnika.v14i1.2400
Ulfa; Bogor Agricultural University Khaira , Imas Sukaesih; Bogor Agricultural University Sitanggang , Lailan; Bogor Agricultural University Syaufina
Detection and prediction of peatland cover changes needs to be done in the rapid rate of deforestation in Indonesia. This work applied Support Vector Machine (SVM) and Markov Chain Model on multitemporal satellite data. The study area is located in the Rokan Hilir district, Riau Province. SVM classification technique used to extract information from satellite data for the years 2000, 2004, 2006, 2009 and 2013. The Markov Chain Model was used to predict future peatland cover. The SVM classification result showed that the Kappa accuracy of peatland cover classification is more than 0.92. The non vegetation areas increased to 307% and the sparse vegetation areas increased to 22% between 2000 and 2013, while dense vegetation areas decreased to 61%. Prediction of future land cover by the Markov Chain Model showed that the use of multitemporal satellite data with 3 years interval provides accurate result for predicting peatland cover changes.
Volume: 14
Issue: 1
Page: 294-301
Publish at: 2016-03-01

Power Quality Analysis of Integration Photovoltaic Generator to Three Phase Grid under Variable Solar Irradiance Level

10.12928/telkomnika.v14i1.3298
Amirullah; Electrical Engineering Department, Industrial Technology Faculty, Institut Teknologi Sepuluh Nopember Surabaya Indonesia, Electrical Engineering Study Program, Engineering Faculty, University of Bhayangkara Surabaya, Amirullah , Ontoseno; Electrical Engineering Department, Industrial Technology Faculty, Institut Teknologi Sepuluh Nopember Surabaya Indonesia Penangsang , Adi; Electrical Engineering Department, Industrial Technology Faculty, Institut Teknologi Sepuluh Nopember Surabaya Indonesia Soeprijanto
Objective of research is to analyze the influence of solar irradiance and integration of  photovoltaic (PV) generator to power quality of three phase grid on the constant temperature and load, based on changes in some level of integration of  PV generator. Power quality aspects studied are fluctuation or changing, and harmonics of voltage and current on eight scenarios PV generator connected to three-phase grid, using passive filter circuit model double band pass (double tuned). Research shows that voltage and current values on the PCC bus before use double tuned passive filter on the condition only connect single generator is still stable. However, if the PV generator connected to the three phase grid, amounted to more than one generation, voltage and current grid becomes unstable (fluctuation). At the level of solar radiation remains, the greater number of PV generators connected to the grid three-phase, then the values of voltage and current THD increases. At the level of solar irradiance increases, average THD of voltage and current grid also increased. Avarage THD of voltage and current grid is reduced after double tuned passive filter installed. Therefore, double tuned passive filter able to improve profile of voltage and current THD grid as a result of the integration of a number of PV power generators in three-phase grid according IEEE Standard 519-1992. Simulation and analysis of this research use Matlab/Simulink. 
Volume: 14
Issue: 1
Page: 29-38
Publish at: 2016-03-01

Improving the Channel Utilization of Basic Safety Message in VANETs with Superposition Coded Modulation

10.12928/telkomnika.v14i1.1355
Xiang; Tongji University Li , Chao; Tongji University Wang , Fuqiang; Tongji University Liu , Xiaobo; Huaqiao University Yin
In this paper, we propose a broadcast scheme to effectively utilize the scarce and shared wireless medium for vehicular ad-hoc networks (VANETs). By using superposition coded modulation (SCM), information elements that comprise basic safety messages (BSMs) were delivered with different service qualities determined by real-time traffic situations. The optimal power allocation strategy and achievable performance gain of the proposed method were first theoretically analyzed. To apply the proposed method into practice, the hierarchical quadrature amplitude modulation technology was then employed to implement the proposed SCM-based broadcast scheme for VANETs. To evaluate the performance of the proposed method in real-time traffic environments, a joint traffic-communication simulation was further conducted. Results agree that the proposed method extends the coverage of the BSM broadcast while maintaining an acceptable communication reliability to meet the requirement of driving safety.
Volume: 14
Issue: 1
Page: 72-81
Publish at: 2016-03-01
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