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25,002 Article Results

Congestion Relief of Contingent Power Network with Evolutionary Optimization Algorithm

10.12928/telkomnika.v10i1.754
Sandip; Department of Electrical Engineering Techno India Chanda , Abhinandan De; Bengal Engineering and Science University Abhinandan De
This paper presents a differential evolution optimization technique based methodology for congestion management cost optimization of contingent power networks. In Deregulated systems, line congestion apart from causing stability problems can increase the cost of electricity. Restraining line flow to a particular level of congestion is quite imperative from stability as well as economy point of view. Employing ‘Congestion Sensitivity Index’ proposed in this paper, the algorithm proposed can be adopted for selecting the congested lines in a power networks and then to search for a congestion constrained optimal generation schedule at the cost of a minimum ‘congestion management charge’ without any load curtailment and installation of FACTS devices. It has been depicted that the methodology on application can provide better operating conditions in terms of improvement of bus voltage and loss profile of the system. The efficiency of the proposed methodology has been tested on an IEEE 30 bus benchmark system and the results look promising.
Volume: 10
Issue: 1
Page: 1-8
Publish at: 2011-03-01

Hybrid Methods in Designing Sierpinski Gasket Antennas

10.12928/telkomnika.v8i3.624
Mudrik; University of Mercu Buana Alaydrus
 Sierpinki gasket antennas as example of fractal antennas show multiband characteristics. The computer simulation of Sierpinksi gasket monopole with finite ground needs prohibitively large computer memory and computational time. Hybrid methods consist of surface integral equation method and physical optics or uniform geometrical theory of diffraction is expected to alleviate this computational burdens. The full hybridization of the different methods with modifying the incoming electromagnetic waves in case of hybrid method surface integral equation method and physical optics and modification of the Greens function for hybrid method surface integral equation method and uniform geometrical theory of diffraction plays the central role in the observation. A comparison of simulation results of these different methods and are given measurements of a groups of three Sierpinksi gasket antennas are presented. The multiband characteristics of the antennas are observed with some reduction and enhancement of resonances.
Volume: 8
Issue: 3
Page: 225-234
Publish at: 2010-12-01

High Performance Palmprint Identification System Based On Two Dimensional Gabor

10.12928/telkomnika.v8i3.633
I Ketut Gede Darma; Udayana University Putra , Erdiawan; Udayana University Erdiawan
The palmprint is a new recognition method in physiological biometrics. In palmprint region of interest (ROI), the segmentation and feature extraction are two important issues. The main problem in palmprint recognition system is how to extract the region of interest (ROI) and the features of palmprint. This paper introduces two steps in center of mass moment and the application of method for ROI segmentation and then to apply the Gabor two dimensional (2D) filters to obtain palm code as palmprint feature vector. Normalized Hamming distance is used to measure the similarity degrees of two feature vectors of palmprint. The system has been tested by using database 1000 palmprint images which was generated from 5 groups of samples from 200 persons selected randomly. Experiment results show that this system can achieve a high performance with success rate about 98.7% (FRR=1.1667%, FAR=0.1111%, T=0.376).
Volume: 8
Issue: 3
Page: 309-318
Publish at: 2010-12-01

A Simple Instrumentation System for Large Structure Vibration Monitoring

10.12928/telkomnika.v8i3.628
Didik; Brawijaya University R. Santoso
A conventional instrumentation systems in monitoring vibration of large-scale infrastructure building such as bridges, railway, and others structural building, generally has a complex design. Makes it simple would be very useful both in terms of low-cost and easy maintenance. To make system become simple, low cost, and easy in maintenance, this paper proposes a distributed network for implementation system. The system consists of field bus topology, using single-master multi-slave architecture. Master is a control unit, built based on a PC equipped with RS-485 interface. Slave is a sensing unit; each slave is built by integrating a 3-axis vibration sensor within a microcontroller based data acquisition system. Vibration sensor is designed using the main components of a MEMS accelerometer. The software is developed for two functions; a control system hardware and a data processing. To verify performance of the developed instrumentation system, several laboratory tests have been performed. The result shows that the system has good performance.
Volume: 8
Issue: 3
Page: 265-274
Publish at: 2010-12-01

Satellite Imagery and In-situ Data Overlay Approach for Fishery Zonation

10.12928/telkomnika.v8i3.623
Khairul; Syiah Kuala University Munadi , Fardhi; Syiah Kuala University Adria
Remote sensing technology is useful to give a better understanding about the earth’s characteristics. SeaWiFS (sea-viewing wide field-of-view sensor) is one of remote sensors used to observe global ocean phenomena. Previous studies showed that the distribution of chlorophyll-a in the ocean indicates the presence of fish. However, only a few studies tried to directly relate the chlorophyll-a distribution obtained through interpretation of satellite imagery to in-situ data of fish distribution. This paper investigates the relation between chlorophyll-a distribution and fish-capturing points in Aceh Province sea waters using overlay image analysis. The results are useful to identify the potential fishing ground in Aceh. The profile of chlorophyll-a concentration was derived from SeaWIFS satellite imagery and fish-capturing points data was obtained from the fisherman communities of Banda Aceh, starting from June to November 2008. The results show that the chlorophyll-a profile derived from satellite imagery has a positive relationship to fish-capturing point data. The most potential fish-capturing zone in Aceh sea waters is identified at 5-8º north latitude (N) and 96-99º east longitude (E).
Volume: 8
Issue: 3
Page: 217-224
Publish at: 2010-12-01

Chaos on Phase Noise of Van Der Pol Oscillator

10.12928/telkomnika.v8i3.632
Gang Feng; University of Electronic Science and Technology of China Yan , Xian He; University of Electronic Science and Technology of China Huang
 Phase noise is the most important parameter in many oscillators. The proposed method in this paper is based on nonlinear stochastic differential equation for phase noise analysis approach. The influences of two different sources of noise in the Van Der Pol oscillator adopted this method are compared. The source of noise is a white noise process which is a genuinely stochastic process and the other is actually a deterministic system, which exhibits chaotic behavior in some regions. The behavior of the oscillator under different conditions is investigated numerically. It is shown that the phase noise of the oscillator is affected by a noise arising from chaos than a noise arising from the genuine stochastic process at the same noise intensity.
Volume: 8
Issue: 3
Page: 301-308
Publish at: 2010-12-01

An Automatic Identification System of Human Skin Irritation

10.12928/telkomnika.v8i3.627
Abdul; Ahmad Dahlan University Fadlil
Quantitative characterization of human skin irritation is important but it is difficult task to be done. Recently, an identification of human skin is still doing manually. Indeed, the identification of the human skin irritation sample can be very subjective. The analysis of the skin irritation could be conducted using biochemical test, but it is not simple. In this research, a new approach of an automatic human skin identification system based on image pattern recognition is developed to obtain a decision of sample test (whether it has irritation or not). This system design was developed using the following features extraction: gray level histogram (GLH) feature and texture gray level co-occurrence matrices (GLCM). Meanwhile, for a classification  process, using the following distance metric: Manhattan distance and Euclidean distance, or learning vector quantization neural network (LVQ-NN). The combination between feature extractor and classifier methods proposed was used to evaluate the performance system. The experimental results show that the best accuracy for 83.33% was obtained when design system was implementated using GLH or GLCM features through LVQ-NN classifier.     
Volume: 8
Issue: 3
Page: 255-264
Publish at: 2010-12-01

Fast Geometric T2-Fuzzy Based Improved Lower Extremities Stimulation Response

10.12928/telkomnika.v8i3.622
Hendi; Universitas Surabaya Wicaksono
This study emphasizes the use of type-2 fuzzy (T2-Fuzzy) to improve the adaptive proportional-integrative-derivative (PID) control in the lower extremities. Several problems were identified from previous studies and those were the slow achievement of the target angle and the presence of oscillation in the achievement of the target blade. The oscillation occurred as the consequence of deploying the early adaptive PID which was not sufficient to overcome the lower extremities nonlinearity. The difference between proposed method of T2-Fuzzy and the others lies in the defuzzification. This research adopts a fast geometric defuzzification that maintains the level of uncertainty T2-Fuzzy in real-time. A functional electrical stimulation (FES) stimulator is proposed to design and to be connected to the computer for processing the T2-Fuzzy. This stimulator stimulates lower extremities of normal subjects each cycle, and the computer record the point of measured achievement of using a goniometer sensors mounted on a knee joint. The results show that the target point of lower extremities is achieved within three initial cycles without oscillations in the achievement of the angle. It is also found that T2-Fuzzy is able to immediately restore the point of achievement when the external parameters of control occur.
Volume: 8
Issue: 3
Page: 207-216
Publish at: 2010-12-01

A Video Streaming Application Using Mobile Media Application Programming Interface

10.12928/telkomnika.v8i3.631
Ary Mazharuddin; Sepuluh Nopember Institute of Technology Shiddiqi , Henry; Sepuluh Nopember Institute of Technology Pratama , Henning Titi; Sepuluh Nopember Institute of Technology Ciptaningtyas
Recently, the development of mobile phone technology is growing rapidly. These developments led to the emerging of a multimedia mobile phone that supports Wireless Local Area Network (WLAN). However, the use of WLAN technology on mobile phones to access the streaming video is very rarely employed, while the current S60 Symbian operating system as a multimedia mobile phone is very reliable in handling a video. This study presents the making of a video streaming application in mobile phone via a WLAN connection using JSR 135 technology or the Mobile Media API (MMAPI). MMAPI is used to control the process of video streaming and its features. The application uses the two protocols; RTSP and HTTP. Experiment results show that the use of MMAPI on Symbian 60 based mobile phones to do video streaming is feasible and has a good reliability as 0% packet loss on connection. In addition, the times required to play multimedia files are not affected by the size of video streaming files.
Volume: 8
Issue: 3
Page: 293-300
Publish at: 2010-12-01

Lag-Lead Compensator for Shape Memory Alloy in Gripping Manipulation

10.12928/telkomnika.v8i3.626
Made Andik; Politeknik Manufaktur (Polman) Timah Bangka Belitung Setiawan
Shape Memory Alloy (SMA) is emerging actuator for micro and nano application which is interesting to be developed. This paper presents the evaluation of close-loop controller responses of the TiNi SMA spring based gripper by introducing lag, lead and lag-lead compensator. A SMA spring has a diameter of 50 mm wire and 350 gram hanging mass. The driver of the SMA actuator uses pulse width modulation (PWM) signal and it is tested by varying frequencies and duty-cycles. The applied frequencies in this study are 12, 25, 125, 250 and 1150 Hz. Lab-View and DAQ-Card is used as a controller, interfacer and data recorder of the system. The fabricated gripper consists of two fingers and the total angular displacement of the gripper is 300. In advanced application, the experiment coversSMA open loop and close-loop system. The SMA response indicated that the rise-time and the steady-state error of the cloop-loop are shorter and lower than open-loop controller.
Volume: 8
Issue: 3
Page: 245-254
Publish at: 2010-12-01

Cost and Benefit of Information Search using Two Different Strategies

10.12928/telkomnika.v8i3.621
Paulus Insap; UGM Santosa
Searching for information is one major Internet activities during which information seekers may gain benefit as well as incurred some cost. In general, information seekers seldom employ any search strategy for general browsing to explore information space. On the other hand, in certain situation, they may employ certain search strategy, especially those who engage in a fact-finding activity. The objective of this research is to shed light on how search strategy can be used to gain the maximum benefit of information search activities. It borrows the two-factor theory to group Web design elements into benefit and cost manifested as motivating and hygiene factors. This research employed a laboratory experiment with 235 respondents who were participated on this research voluntarily. Respondents were divided into two groups, namely ‘plan-group’ and ‘unplan-group’. Both groups were given certain tasks related to information search. The experiment was followed by a post experiment survey. The result shows that respondents who were in the ‘plan-group’ perceived less benefit and incurred more cost compared to those in the ‘unplan-group’. The future research is proposed at the end of this manuscript.
Volume: 8
Issue: 3
Page: 195-206
Publish at: 2010-12-01

Distributed Monitoring and Controlling Using Microcontroller and Virtual Internet Protocol

10.12928/telkomnika.v8i3.630
Ahmad; Gadjah Mada University (UGM) Ashari
Nowadays, the applications based on TCP/IP (transmission control protocol/internet protocol) network are growing rapidly. By this application monitoring and control functions are easily and widely accessible through networks. Every PC (Personal Computer) can be connected to several microcontroller, but there are difficulties to access microcontroller directly through TCP/IP networks. This research study the use of virtual IP on a PC that connected with several microcontrollers, where each microcontroller is connected to a sensor device to monitoring temperature and a relay for controlling. In this method, each set of the microcontroller can be accessed directly using the IP. The results show that this system can be a distributed monitoring and controlling system which has the ability to record and display the results in the form of graphs. 
Volume: 8
Issue: 3
Page: 285-292
Publish at: 2010-12-01

Harmonic Mitigation Using a Polarized Ramp-time Current-Controlled Inverter

10.12928/telkomnika.v8i3.625
Hanny; Petra Christian University H. Tumbelaka , Lawrence; Aquila Electronics J. Borle
 This paper describes the implementation of a shunt active power filter for a three-phase four-wire system to overcome the power quality problems generated by mixed non-linear loads which are a combination of harmonic, reactive and unbalanced components. The filter consists of a three-phase current-controlled voltage source inverter (CC-VSI) with a filter inductor at the AC output and a DC-bus capacitor. The CC-VSI is operated to directly control the grid current in order to be sinusoidal and in phase with the grid voltage without sensing the load currents. The switching is controlled by using polarized ramp-time current control, which is based on the concept of zero average current error (ZACE) with a fixed switching frequency. The laboratory experiment results indicate that the filter is able to mitigate the harmonics and the reactive power, so that the grid currents are sinusoidal, in phase with the grid voltages, and symmetric although the grid voltage contains harmonics.
Volume: 8
Issue: 3
Page: 235-244
Publish at: 2010-12-01

An Adaptive Modulation in Millimeter-Wave Communication System for Tropical Region

10.12928/telkomnika.v8i3.634
Suwadi; Institut Teknologi Sepuluh Nopember Surabaya Suwadi , Gamantyo; Institut Teknologi Sepuluh Nopember Surabaya Hendrantoro , Wirawan; Institut Teknologi Sepuluh Nopember Surabaya Wirawan
 The dominant propagation factor affecting the outage and the spectral efficiency of millimeter-wave communication systems operating at frequencies 30 GHz is rain attenuation. An adaptive modulation is proposed to improve the outage and spectral efficiency performance of the system. This paper presents an analytical procedure for the evaluation of the outage and spectral efficiency of the system in Indonesia with heavy rain rate. By comparing analytic and simulation a validation was conducted. The results show that adaptive modulation can significantly improve the outage and the spectral efficiency performance of the system, for links with long distance.
Volume: 8
Issue: 3
Page: 319-326
Publish at: 2010-12-01

A Novel Dynamic Overmodulation Strategy of Direct Torque Control

10.12928/telkomnika.v8i3.629
Auzani; Universiti Teknikal Malaysia Melaka (UTeM) Jidin , Tole; Universitas Ahmad Dahlan (UAD) Sutikno , Aiman Zakwan; Ecole Supérieur d’Ingénieur en Electronique et Electrotechnique (ESIEE Engineering Paris) Jidin , Nik Rumzi Nik; Universiti Teknologi Malaysia (UTM) Idris , Abdul Halim Mohd; Universiti Teknologi Malaysia (UTM) Yatim
The direct torque control-space vector modulation (DTC-SVM) is well-known for achieving excellent dynamic overmodulation. However, the method uses complicated predictive stator flux vector control and requires high precision stator flux vector to define overmodulation mode. This paper proposes a straightforward dynamic overmodulation method and constant switching frequency controller without SVM to obtain a faster dynamic torque response in DTC for induction machines. To perform this method, the flux error status produced from the flux hysteresis comparator during dynamic condition is modified slightly before being fed to the look-up table. The verification of proposed method was performed using MATLAB/Simulink simulation package. The effects of different switching and operating condition on dynamic torque performance are analyzed. The result shows that a faster torque response is achieved in proposed dynamic overmodulation DTC method. The main benefit of the proposed method is its simplicity since only minor modification is made to the basic DTC hysteresis-based structure. 
Volume: 8
Issue: 3
Page: 275-284
Publish at: 2010-12-01
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