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23,598 Article Results

Fluctuations Mitigation of Variable Speed Wind Turbine through Optimized Centralized Controller

10.12928/telkomnika.v10i4.859
Ali; University of Sistan and Baluchestan Mohammadi , Sajjad; University of Sistan and Baluchestan Farajianpour , Saeed; University of Sistan and Baluchestan Tavakoli , S. Masoud; University of Sistan and Baluchestan Barakati
A wind energy conversion system (WECS) including a variable wind turbine in grid-connected mode is considered to control. In this paper, each component of WECS model is systematically presented and then the integrated overall model is validated.Regarding to nonlinear nature of WECS and the complex system structure as multiple-input multiple-output (MIMO), it is difficult to find a proper control strategy. To simplify the control design, a centralized controller, which is compatible with systematic modelling, is employed. In addition, to enhance the centralized controller performance, an optimization based on genetic algorithm (GA) is accomplished. Simulation results demonstate the effectivesness of the proposed control startegy to mitigation fluctuations.
Volume: 10
Issue: 4
Page: 703-714
Publish at: 2012-12-01

View Synthesizing for a Large-Scale Object in a Scene

10.12928/telkomnika.v10i4.868
Thin Lai Lai; University of Computer Studies Thein , Myint Myint; University of Computer Studies Sein
A robust method for panorama view reconstruction of a scene is presented. The images of a scene are acquired by moving a camera to multiple viewpoints. We present a robust method of panorama synthesizing based on image mosaicing approach. The edge detection and feature points extraction are performed for each image. The corresponding feature points between two successive images are estimated and the between these images is computed. These two images are integrated based on the different of minimum threshold values between them. After that, the full-view of a scene is reconstructed by merging the successive integrated images by developed image mosaicing approach. This research describes how to establish feature correspondences between images accurately and effectively. Image registration technique provides an initial estimation for establishing feature correspondences of point features. The linear solution with the reliable correspondences makes the computation of the geometric transformation between two images.
Volume: 10
Issue: 4
Page: 795-800
Publish at: 2012-12-01

Accelerated Aging Effect on Epoxy-polysiloxane-Rice Husk Ash Polymeric Insulator Material

10.12928/telkomnika.v10i4.853
Tumiran; Gadjah Mada University Tumiran , Arif; Gadjah Mada University, Moslem University of Indonesia Jaya , Hamzah; Gadjah Mada University Berahim , Rochmadi; Gadjah Mada University Rochmadi
The performances of outdoor polymeric insulators are influenced by environmental conditions. The use of polymeric materials in a particular composition can be produced insulators that are resistant to environmental influences. This paper presents the effect of artificial tropical climate on the hydrophobicity, equivalent salt deposit density (ESDD), surface leakage current, flashover voltage, and surface degradation on epoxy-polysiloxane polymeric insulator materials with rice husk ash (RHA). Test samples are made at room temperature vulcanized (RTV) of various composition of epoxy-polysiloxane with rice husk ash as filler. The aging was carried out in test chamber at temperature from 50oC to 62oC, relative humidity of 60% to 80%, and ultraviolet (UV) radiation 21.28 w/cm2 in daylight conditions for 96 hours. The experiment results showed that the flashover voltage fluctuates from 34.13 kV up to 40.92 kV and tends to decrease on each variation of material composition. The surface leakage current fluctuates and tends to increase. Test samples with higher filler content result greater hydrophobicity, smaller equivalent salt deposit density, and smaller critical leakage current, which caused the increase of the flashover voltage. Insulator material (RTVEP3) showed the best performance in tropical climate environment. Artificial tropical aging for short duration gives less effect to the surface degradation of epoxy-polysiloxane insulator material.
Volume: 10
Issue: 4
Page: 655-666
Publish at: 2012-12-01

Fuzzy Expert System for Tropical Infectious Disease by Certainty Factor

10.12928/telkomnika.v10i4.872
I Ketut Gede Darma; Udayana University Putra , Putu Manik; Bali State Polytechnic Prihatini
Communication between doctor and patient play an important role in determining the diagnosis of the illness suffered by the patient. Consultation time constraints led to insufficient information obtained to produce a diagnosis. This limitation is overcome by developing an expert system using fuzzy logic to represent the vagueness of symptoms experienced by patients and the certainty factor represents a relationship between the symptoms and disease. Fuzzy logic method begins with the acquisition of knowledge to produce the facts and rules, implication process, composition and defuzzification. The result of defuzzification used in the calculation of sequential and combined certainty factor which represent the belief percentage of diseases diagnosis that suffered by the patient. The results of the expert diagnosis with expert system for the given cases indicates the system, has the similarity diagnosis with the expert at 93.99%.
Volume: 10
Issue: 4
Page: 825-836
Publish at: 2012-12-01

Finite Element Method Using PDETOOL of Matlab for Hybrid Stepper Motor Design

10.12928/telkomnika.v10i4.863
E.V.C. Sekhara; Chaitanya Bharathi Institute of Technology (CBIT) Rao , P.V.N. Prasad; University College of Engineering (UCE) P.V.N. Prasad
This paper presents eight topologies design of permanent magnet hybrid (PMH) stepper motor for it’s magnetic circuit performance analysis using finite element method by PDETOOL of Matlab. The topologies are designed according to the number of stator teeth and length of airgap. This analysis is used to know mmf distribution due to permanent magnet and by exitation coil.This analysis helps to chose best design topology for better mmf distribution.
Volume: 10
Issue: 4
Page: 741-748
Publish at: 2012-12-01

Indoor Localization System based on Artificial Landmarks and Monocular Vision

10.12928/telkomnika.v10i4.848
Andry Maykol G.; University of Porto Pinto , A. Paulo; University of Porto Moreira , Paulo G.; University of Porto Costa
 This paper presents a visual localization approach that is suitable for domestic and industrial environments as it enables accurate, reliable and robust pose estimation. The mobile robot is equipped with a single camera which update sits pose whenever a landmark is available on the field of view. The innovation presented by this research focuses on the artificial landmark system which has the ability to detect the presence of the robot, since both entities communicate with each other using an infrared signal protocol modulated in frequency. Besides this communication capability, each landmark has several high intensity light-emitting diodes (LEDs) that shine only for some instances according to the communication, which makes it possible for the camera shutter and the blinking of the LEDs to synchronize. This synchronization increases the system tolerance concerning changes in brightness in the ambient lights over time, independently of the landmarks location. Therefore, the environment’s ceiling is populated with several landmarks and an Extended Kalman Filter is used to combine the dead-reckoning and landmark information. This increases the flexibility of the system by reducing the number of landmarks required. The experimental evaluation was conducted in a real indoor environment with an autonomous wheelchair prototype.
Volume: 10
Issue: 4
Page: 609-620
Publish at: 2012-12-01

Optimal Design of Fuel-cell, Wind and Micro-hydro Hybrid System using Genetic Algorithm

10.12928/telkomnika.v10i4.858
Soedibyo; Sepuluh Nopember Institute of Technology (ITS) Soedibyo , Heri; Sepuluh Nopember Institute of Technology (ITS) Suryoatmojo , Imam; Sepuluh Nopember Institute of Technology (ITS) Robandi , Mochamad; Sepuluh Nopember Institute of Technology (ITS) Ashari
The target of stand-alone hybrid power generation system was to supply the load demand with high reliability and economically as possible. An intelligent optimization technique using Genetic Algorithm is required to design the system.This study utilized Genetic Algorithm method to determine the optimal capacities of hydrogen, wind turbines and micro-hydro unit according to the minimum cost objective functions.The minimum cost valutes to these two factors. In this study, the cost objective function included the annual capital cost, annual operation maintenance cost, annual replacement cost and annual customer damage cost. The proposed method will be used to optimize the hybrid power generation system located in Leuwijawa village in Central Java of Indonesia. Simulation results showed that the optimum configuration can be achieved using 19.85 ton of hydrogen tanks, 21x100 kW wind turbines and 610 kW of micro-hydro unit respectively
Volume: 10
Issue: 4
Page: 695-702
Publish at: 2012-12-01

Colour Perception on Facial Expression towards Emotion

10.12928/telkomnika.v10i4.867
Ching Yee; Universiti Teknologi Malaysia Yong , Rubita; Universiti Teknologi Malaysia Sudirman , Kim Mey; Universiti Teknologi Malaysia Chew
This study is to investigate human perceptions on pairing of facial expressions of emotion with colours. A group of 27 subjects consisting mainly of younger and Malaysian had participated in this study. For each of the seven faces, which express the basic emotions neutral, happiness, surprise, anger, disgust, fear and sadness, a single colour is chosen from the eight basic colours for the “match” of best visual look to the face accordingly. The different emotions appear well characterized by a single colour. The approaches used in this experiment for analysis are psychology disciplines and colours engineering. These seven emotions are being matched by the subjects with their perceptions and feeling. Then, 12 male and 12 female data are randomly chosen from among the previous data to make a colour perception comparison between genders. The successes or failures in running of this test depend on the possibility of subjects to propose their every single colour for each expression. The result will translate into number and percentage as a guide for colours designers and psychology field.
Volume: 10
Issue: 4
Page: 783-794
Publish at: 2012-12-01

Genetic Algorithm of Sliding Mode Control Design for Manipulator Robot

10.12928/telkomnika.v10i4.852
Ahmad Riyad; Politeknik Negeri Batam Firdaus , Arief Syaichu; STEI – Institut Teknologi Bandung Rahman
The dynamical model of manipulator robot is represented by equations systems which are nonlinear and strongly coupled. Furthermore, the inertial parameters of manipulator depend on the payload which is often unknown and variable. The sliding mode controller (SMC) provides an effective and robust means of controlling nonlinear plants. The performance of SMC depends on control parameter selection of gain switching (k) and sliding surface constant (s). It is very difficult to obtain the optimal control parameters. In this paper, a control parameter selection algorithm is proposed by genetic algorithm to select the gain switching (k) and sliding surface constant parameter (s) so that the controlled system can achieve a good overall performance in the sliding mode controller design. Testing is done by giving a reference position for joint 1 and joint 2 of the robot manipulator of 45O (degree) with the controller performance indicator is settling time
Volume: 10
Issue: 4
Page: 645-654
Publish at: 2012-12-01

A Low Cost C8051F006 SoC-Based Quasi-Static C-V Meter for Characterizing Semiconductor Devices

10.12928/telkomnika.v10i4.862
Endah; Universitas Negeri Surabaya Rahmawati , Riska; Universitas Bengkulu Ekawita , Maman; Institut Teknologi Bandung Budiman , Mikrajuddin; Institut Teknologi Bandung Abdullah , Khairurrijal; Institut Teknologi Bandung Khairurrijal
Based on a C8051F006 SoC (system on-a-chip), a simple and low cost quasi-static capacitance-voltage (C-V) meter was designed and developed to obtain C-V characteristics of semiconductor devices. The developed C-V meter consists of a capacitance meter, a programmable voltage source, a C8051F006 SoC-based slave controller, and a personal computer (PC) as a master controller. The communication between the master and slave controllers is facilitated by the RS 232 serial communication. The accuracy of the C-V meter was guaranteed by the calibration functions, which are employed by the program in the PC and obtained through the calibration processes of analog to digital converter (ADC), digital to analog converters (DACs) of the C8051F006 SoC, and the programmable voltage source. Examining 33-pF and 1000-pF capacitors as well three different p-n junction diodes, it was found that the capacitances of common capacitors are in the range of specified values and typical C-V curves of p-n junction diodes are achieved.
Volume: 10
Issue: 4
Page: 733-740
Publish at: 2012-12-01

Image Encryption on Mobile Phone using Super Encryption Algorithm

10.12928/telkomnika.v10i4.871
Emy; Institute of Science & Technology AKPRIND Yogyakarta Setyaningsih , Catur; Institute of Science & Technology AKPRIND Yogyakarta Iswahyudi , Naniek; Institute of Science & Technology AKPRIND Yogyakarta Widyastuti
Mobile phones have limited memory and computational resources. Modern encryption algorithms such as DES, AES, IDEA uses a complicated and complex algorithm, that are not suitable for image encryption on mobile phones. Necessary, it is tradeoff between speed, security, and flexibility. Problem to be investigated and resolved is how to get the image encryption algorithm which is simple yet safe, with the lightweight and efficient computing. The algorithm developed in this study was super-encryption algorithm that combines Playfair cipher and the Vigenere cipher. The experimental results show the cipher image histogram has a distribution of diversity and a significant difference to the plain image histogram, and frequency of occurrence of each intensity value in the histogram of cipher image is also uneven, which means can not provide clues to do statistical attack. The experimental results also showed a correlation between the elements of the image after encryption has decreased significantly. The average of quality encryption showed that the rate of change of image pixels is high enough so that cipher image difficult to identify. Tests on a cell phone showed that this algorithm requires only small computational resources. This shows that the algorithm is quite effective for image encryption on mobile phones.
Volume: 10
Issue: 4
Page: 815-824
Publish at: 2012-12-01

Realistic Human Motion Preservation-Imitation Development on Robot with Kinect

10.12928/telkomnika.v10i4.847
Abdul; University of Indonesia Muis , Wisnu; University of Indonesia Indrajit
At most, motion generation on robot is usually done through complex computation in off-line mode and straightforward method. In straightforward method, the operator drives robot to certain pose either with moving manipulator tool-tip with hand or remotely. Once the desired pose achieved, the current pose is saved to memory. However, these methods are time consuming. An easy and quick approach is by imitating an object motion to robot with sensing devices. There have been numerous efforts for motion imitation either by using position sensitive detector (PSD) or by using stereo camera. However, a calibrated pre-condition should be done initially, which is not possible for natural movement. Here, this paper proposed motion preservation by capturing human motion naturally through Kinect and then reproduced human motion on humanoid robot simultaneously. In addition, the motions are also preserved in database for later used on robot motion generation and teaching as well. Furthermore, the robot motions are developed to run smoothly and close to human eye ability. The proposed method has been validated in experimental results by capturing and reproducing human motion on robot in rate of 20Hz with340us computation cost for each process.
Volume: 10
Issue: 4
Page: 599-608
Publish at: 2012-12-01

Optimal Placement and Sizing of Thyristor-controlled-series-capacitor using Gravitational Search Algorithm

10.12928/telkomnika.v10i4.857
Purwoharjono; Institut Teknologi Sepuluh Nopember, Universitas Tanjungpura Purwoharjono , Muhammad; Institut Teknologi Sepuluh Nopember Abdillah , Ontoseno; Institut Teknologi Sepuluh Nopember Penangsang , Adi; Institut Teknologi Sepuluh Nopember Soeprijanto
This paper represents the Gravitational Search Algorithm (GSA) that can be used to determine the optimal location and rating of Thyristor controlled Series Capacitor (TCSC). TCSC is equipment used to regulate and improve power flow in power system. The method used in this study was GSA. TCSC were the implemented on 500kV Java-Bali Power System. Loadflow results before optimization using Newton Rapshon method showed that active power loss was 297.607MW. While loadflow results after optimization using GSA with 5-TCSC obtained were 287.926MW of active power loss, with 10-TCSC, it was obtained 281.143MW of active power loss. In addition, using 15-TCSC, active power loss obtained was 279.405MW. GSA methods can be used to minimize power losses and transmission lines as well as to improve value of voltage in the range of 0.95+ 1.05pu compared with loadflow results before optimization.The more TCSC is used, then value of active power losses small.
Volume: 10
Issue: 4
Page: 683-694
Publish at: 2012-12-01

Face Recognition Using Holistic Features and Linear Discriminant Analysis Simplification

10.12928/telkomnika.v10i4.866
I Gede Pasek Suta; Mataram University Wijaya , Keiichi; Kumamoto University Uchimura , Gou; Kumamoto University Koutaki
This paper proposes an alternative approach to face recognition algorithm that is based on global/holistic features of face image and simplified linear discriminant analysis (LDA). The proposed method can overcome main problems of the conventional LDA in terms of large processing time for retraining when a new class data is registered into the training data set. The holistic features of face image are proposed as dimensional reduction of raw face image. While, the simplified LDA which is the redefinition of between class scatter using constant global mean assignment is proposed to decrease time complexity of retraining process. To know the performance of the proposed method, several experiments were performed using several challenging face databases: ORL, YALE, ITS-Lab, INDIA, and FERET database. Furthermore, we compared the developed algorithm experimental results to the best traditional subspace methods such as DLDA, 2DLDA, (2D)2DLDA, 2DPCA, and (2D)22DPCA. The experimental results show that the proposed method can be solve the retraining problem of the conventional LDA indicated by requiring shorted retraining time and stable recognition rate.
Volume: 10
Issue: 4
Page: 771-782
Publish at: 2012-12-01

Measurement and Simulation Techniques for Piezoresistive Microcantilever Biosensor Applications

10.12928/telkomnika.v10i4.861
Aan; Polytechnic of Bangka Belitung Febriansyah , Ratno; Agency for the Assessment and Application of Technology (BPPT) Nuryadi , Djoko; Indonesia University Hartanto
Applications of microcantileversas biosensors have been explored by many researchers for the applications in medicine, biological, chemistry, and environmental monitoring. This research discusses a design of measurement method and simuations forpiezoresistivemicrocantileveras a biosensor, which consist of designing Wheatstone bridge circuit as object detector, simulation of resonance frequency shift based on Euler Bernoulli Beam equation, and microcantilever vibration simulation using COMSOL Multiphysics 3.5. The piezoresistivemicrocantilever used here is Seiko Instrument Technology (Japan) product with length of 110 μm, width of 50 μm, and thickness of 1 μm. Microcantilever mass is 12.815 ng, including the mass receptor. The sample object in this research is bacteria EColi. One bacteria mass is assumed to 0.3 pg. Simulation results show that the mass of one bacterium will cause the deflection of 0.03053 nm and resonance frequency value of 118.90 kHz. Moreover, four bacterium will cause the deflection of 0.03054 nm and resonance frequency value of 118.68 kHz. These data indicate that the increasing of the bacteria mass increases the deflection value and reduces the value of resonance frequency.
Volume: 10
Issue: 4
Page: 725-732
Publish at: 2012-12-01
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