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25,002 Article Results

Dynamic Model and Robust Control of Flexible Link Robot Manipulator

10.12928/telkomnika.v9i2.698
Mohammad; Universitas Negeri Yogyakarta Khairudin , Zaharuddin; Universiti Teknologi Malaysia Mohamed , Abdul Rashid; Universiti Teknologi Malaysia Husain
The problems of a flexible link manipulator are uncertainties and parametric nonlinearities. This paper presents design and development of a robust control based on linear quadratic regulator (LQR) for a flexible link manipulator.  System performances were evaluated in terms of input tracking capability of hub angular position response, end-point displacement, end-point residual and hub velocity. For the controller of the system, LQR was developed to solve flexible link robustness and input tracking capability of hub angular position. The results achieved by the proposed controller are compared with conventional PID, to substantiate and verify the advantages of the proposed scheme and its promising potential in control of a flexible link manipulator. The robust control presented faster settling time and smaller overshoot responses and tracking performances of the proposed controller compared with PID controllers.
Volume: 9
Issue: 2
Page: 279-286
Publish at: 2011-08-01

Self Oscillating Mixer with Dielectric Resonator for Low Noise Block Application

10.12928/telkomnika.v9i2.707
Achmad; Institut Teknologi Bandung (ITB) Munir , Endon; Institut Teknologi Bandung (ITB) Bharata
In this paper, the development of a self oscillating mixer (SOM) as part of a low noise block (LNB) for a satellite television receiver is investigated numerically and experimentally. In contrast to other mixers, the developed SOM requires no separate local oscillator as it generates own local oscillator signal. The SOM is developed using a monolithic microwave integrated circuit (MMIC) comprised of two bipolar transistors coupled as a Darlington pair and a dielectric resonator to establish a local oscillator signal. The SOM is designed to oscillate at 3.62GHz driven from 50W signal generator. The prototype of SOM is fabricated on a dielectric substrate of glass-reinforced hydrocarbon/ceramic lamination (RO4350B) board which has a thickness of 0.762mm and relative permittivity of 3.66. The prototype is then characterized experimentally and exhibits a conversion gain of 8dB with the input and output voltage standing wave ratio (VSWR) less than 2 across the 2520MHz to 2670MHz operating frequency band.
Volume: 9
Issue: 2
Page: 351-356
Publish at: 2011-08-01

Neural Network Based Indexing and Recognition of Power Quality Disturbances

10.12928/telkomnika.v9i2.691
Manoj; Malaviya National Institute of Technology Gupta , Rajesh; Malaviya National Institute of Technology Kumar , Ram Awtar; Malaviya National Institute of Technology Gupta
Power quality (PQ) analysis has become imperative for utilities as well as for consumers due to huge cost burden of poor power quality. Accurate recognition of PQ disturbances is still a challenging task, whereas methods for its indexing are not much investigated yet. This paper expounds a system, which includes generation of unique patterns called signatures of various PQ disturbances using continuous wavelet transform (CWT) and recognition of these signatures using feed-forward neural network. It is also corroborated that the size of signatures of PQ disturbances are proportional to its magnitude, so this feature of the signature is used for indexing the level of PQ disturbance in three sub-classes’ viz. high, medium, and low. Further, the effect of number of neurons used by neural network on the performance of recognition is also analyzed. Almost 100% accuracy of recognition substantiates the effectiveness of the proposed system.  
Volume: 9
Issue: 2
Page: 227-236
Publish at: 2011-08-01

Efficient JPEG 2000 Image Compression Scheme for Multihop Wireless Networks

10.12928/telkomnika.v9i2.702
Mohsen; Université de Monastir Nasri , Abdelhamid; Université de Monastir Helali , Halim; Université de Monastir Sghaier , Hassen; Université de Monastir Maaref
 When using wireless sensor networks for real-time data transmission, some critical points should be considered. Restricted computational power, reduced memory, narrow bandwidth and energy supplied present strong limits in sensor nodes. Therefore, maximizing network lifetime and minimizing energy consumption are always optimization goals. To overcome the computation and energy limitation of individual sensor nodes during image transmission, an energy efficient image transport scheme is proposed, taking advantage of JPEG2000 still image compression standard using MATLAB and C from Jasper. JPEG2000 provides a practical set of features, not necessarily available in the previous standards. These features were achieved using techniques: the discrete wavelet transform (DWT), and embedded block coding with optimized truncation (EBCOT). Performance of the proposed image transport scheme is investigated with respect to image quality and energy consumption. Simulation results are presented and show that the proposed scheme optimizes network lifetime and reduces significantly the amount of required memory by analyzing the functional influence of each parameter of this distributed image compression algorithm. 
Volume: 9
Issue: 2
Page: 311-318
Publish at: 2011-08-01

Enhancement of Iris Recognition System Based on Phase Only Correlation

10.12928/telkomnika.v9i2.711
Fitri; Syiah Kuala University Arnia , Nuriza; Syiah Kuala University Pramita
Iris recognition system is one of biometric based recognition/identification systems. Numerous techniques have been implemented to achieve a good recognition rate, including the ones based on Phase Only Correlation (POC). Significant and higher correlation peaks suggest that the system recognizes iris images of the same subject (person), while lower and unsignificant peaks correspond to recognition of those of difference subjects. Current POC methods have not investigated minimum iris point that can be used to achieve higher correlation peaks. This paper proposed a method that used only one-fourth of full normalized iris size to achieve higher (or at least the same) recognition rate. Simulation on CASIA version 1.0 iris image database showed that averaged recognition rate of the proposed method achieved 67%, higher than that of using one-half (56%) and full (53%) iris point. Furthermore, all (100%) POC peak values of the proposed method was higher than that of the method with full iris points.     
Volume: 9
Issue: 2
Page: 387-394
Publish at: 2011-08-01

Transient Stability Enhancement of the Power System with Wind Generation

10.12928/telkomnika.v9i2.697
Sujith; National Institute of Technology Hamirpur Mohandas , Ashwani Kumar; National Institute of Technology Hamirpur Chandel
 Transient stability analysis of a power system with wind generation has been addressed in this paper. The effects of automatic voltage regulators, power system stabilizers, and static synchronous compensators on transient stability of a power system are investigated. Various simulation results show that addition of power system stabilizer and static synchronous compensators reduce the rotor angle oscillations. However, the static synchronous compensator shows better damping characteristics and improves the stability of the wind integrated system. It has been established that the static synchronous compensator damps out the speed oscillations in the shaft of the constant speed wind turbine. A transient impact index has been proposed to prove that the static compensator damps out the rotor oscillations.
Volume: 9
Issue: 2
Page: 267-278
Publish at: 2011-08-01

Numerical Design of Ultra-Wideband Printed Antenna for Surface Penetrating Radar Application

10.12928/telkomnika.v9i2.706
Roy B. V. B.; Institut Teknologi Harapan Bangsa Simorangkir , Achmad; Institut Teknologi Bandung Munir
Surface penetrating radar (SPR) is an imaging device of electromagnetic wave that works by emitting and transmitting a narrow period pulse through the antenna. Due to the use of narrow period pulse, according to the Fourier transform duality, therefore ultra-wideband (UWB) antenna becomes one of the most important needs in SPR system. In this paper, a novel UWB printed antenna is proposed to be used for SPR application. Basically, the proposed antenna is developed from a rectangular microstrip antenna fed by symmetric T-shaped. Some investigation methods such as resistive loading, abrupt transition, and ground plane modification are attempted to achieve required characteristics of bandwidth, radiation efficiency, and compactness needed by the system. To obtain the optimum design, the characteristics of proposed antenna are numerically investigated through the physical parameters of antenna. It is shown that proposed antenna deployed on an FR-4 Epoxy substrate with permittivity of 4.3 and thickness of 1.6mm has a compact size of 72.8mm x 60.0mm and a large bandwidth of 50MHz-5GHz which is suitable for SPR application.
Volume: 9
Issue: 2
Page: 341-350
Publish at: 2011-08-01

Maximum Output Power Tracking of Wind Turbine Using Intelligent Control

10.12928/telkomnika.v9i2.690
Muldi; Universitas Negeri Padang (UNP), Institut Teknologi Sepuluh Nopember (ITS) Yuhendri , Mochamad; Institut Teknologi Sepuluh Nopember (ITS) Ashari , Mauridhi Hery; Institut Teknologi Sepuluh Nopember (ITS) Purnomo
 The Output power of wind turbine is determined by wind speed. The Output power can be adjusted by controlling the generator speed and pitch angle of wind turbine. When the wind speed below the wind turbine rated, the output power of generator can be maximized by controlling the generator speed at point of maximum power coefficient. When the wind speed above the wind turbine rated, output power of wind turbine will exceed the power generators rated. In this condition, the output power of wind turbine needs to be regulated to conform to the generator power rate. Output power of wind turbine can be regulated by adjusting the pitch angle of wind turbine. In this paper is developed the control strategies based intelligent control for controlling the generator speed and pitch angle of wind turbine, so the  maximum output power tracking (MOPT) of wind turbine can be obtained at any wind speed variations. Generator speed is controlled using PI Fuzzy Logic Controller (PI-FLC) based Direct Field Oriented Control (DFOC). Pitch angle of wind turbine is controlled using Elman Recurrent Neural Network (RENN). The simulation results with Matlab Simulink shows that the both controller was successfully regulates the output power when the wind speed above the wind turbine rated and the output power can be maximum when the wind speed below the wind turbine rated. 
Volume: 9
Issue: 2
Page: 217-226
Publish at: 2011-08-01

Efficiency of Polymer Electrolyte Membrane Fuel Cell Stack

10.12928/telkomnika.v9i2.701
Agung; University of Surabaya (UBAYA) Prayitno , Olive; HAN University of Applied Sciences Kubumwe , Hans; HAN University of Applied Sciences Bosma , Edwin; HAN University of Applied Sciences Tazelaar
This paper applies a feedforward control of optimal oxygen excess ratio that maximize net power (improve efficiency) of a NedStack P8.0-64 PEM fuel cell stack (FCS) system. Net powers profile as a function of oxygen excess ratio for some points of operation are analyzed by using FCS model. The relationships between stack current and the corresponding control input voltage that gives an optimal oxygen excess ratio are used to design a feedforward control scheme. The results of this scheme are compared to the results of a feedforward control using a constant oxygen excess ratio. Simulation results show that optimal oxygen excess ratio improves fuel cell performance compared to the results of constant oxygen excess ratio. The same procedures are performed experimentally for the FCS system. The behaviour of the net power of the fuel cell stack with respect to the variation of oxygen excess ratio is analyzed to obtain optimal values. Data of stack current and the corresponding voltage input to the compressor that gives optimal values of oxygen excess ratio are used to develop a feedforward control.  Feedforward control based on constant and optimal oxygen excess ratio control, are implemented in the NedStack P8.0-64 PEM fuel cell stack system by using LabVIEW. Implementation results shows that optimal oxygen excess ratio control improves the fuel cell performance compared to the constant oxygen excess ratio control.
Volume: 9
Issue: 2
Page: 303-310
Publish at: 2011-08-01

Low-Cost Based Eye Tracking and Eye Gaze Estimation

10.12928/telkomnika.v9i2.710
I Ketut Gede Darma; Udayana University Putra , Agung; Udayana University Cahyawan , Yandi; Udayana University Perdana
The costs of current gaze tracking systems remain too high for general public use. The main reason for this is the cost of parts, especially high-quality cameras and lenses and cost development. This research build the low cost based for gaze tracking system. The device is built by utilizing of modified web camera in infrared spectrum. A new technique is also proposed here in order to detect the center pupil coordinate based on connected component labeling. By combination the pupils coordinate detection method with third order polynomial regression in calibration process to determine the gaze point. The experiment results show our system has an acceptable accuracy rate with error pixel 0.39o in visual degree.
Volume: 9
Issue: 2
Page: 377-386
Publish at: 2011-08-01

Levenberg-Marquardt Recurrent Networks for Long-Term Electricity Peak Load Forecasting

10.12928/telkomnika.v9i2.696
Yusak; Petra Christian University Tanoto , Weerakorn; Energy Field of Study Asian Institute of Technology Ongsakul , Charles O.P.; Energy Field of Study Asian Institute of Technology Marpaung
 Increasing electricity demand in Java-Madura-Bali, Indonesia, must be addressed appropriately to avoid blackout by determining accurate peak load forecasting. Econometric approach may not be sufficient to handle this problem due to limitation in modelling nonlinear interaction of factors involved. To overcome this problem, Elman and Jordan Recurrent Neural Network based on Levenberg-Marquardt learning algorithm is proposed to forecast annual peak load of Java-Madura-Bali interconnection for 2009-2011. Actual historical regional data which consists of economic, electricity statistic and weather during 1995-2008 are applied as inputs. The networks structure is firstly justified using true historical data of 1995-2005 to forecast peak load of 2006-2008. Afterwards, peak load forecasting of 2009-2011 is conducted subsequently using actual historical data of 1995-2008. Overall, the proposed networks shown better performance compared to that obtained by Levenberg-Marquardt-Feedforward network, Double-log Multiple Regression, and with projection by PLN for 2006-2010.
Volume: 9
Issue: 2
Page: 256-266
Publish at: 2011-08-01

Rotation Invariant Indexing For Image Using Zernike Moments and R–Tree

10.12928/telkomnika.v9i2.705
Saptadi; Satya Wacana Christian University Nugroho , Darmawan; Satya Wacana Christian University Utomo
The Zernike moment algorithm and R-Tree algorithm are known as state of the art in the recognition of images and in the multimedia database respectively. The methods of storing the images and retrieving the similar images based on a query image automatically are the problems in the image database. This paper proposes the method to combine the Zernike moments algorithm and the R–tree algorithm in the image database. The indices of images which are retrieved from the extraction process using Zernike moments algorithm are used as the multidimensional indices to recognize the images. The multidimensional indices of Zernike moments which are stored in the R–tree are compared to the magnitudes of Zernike moments of a query image for searching the similar images. The result shows that the combination of these algorithms can be used efficiently in the image database because the recognition accuracy rate using Zernike moments algorithm is 95.20%.
Volume: 9
Issue: 2
Page: 335-340
Publish at: 2011-08-01

A Hybrid Genetic Algorithm Approach for Optimal Power Flow

10.12928/telkomnika.v9i2.689
Mithun M. Bhaskar; National Institute of Technology Warangal M. Bhaskar , Sydulu; National Institute of Technology Warangal Maheswarapu
This paper puts forward a reformed hybrid genetic algorithm (GA) based approach to the optimal power flow. In the approach followed here, continuous variables are designed using real-coded GA and discrete variables are processed as binary strings. The outcomes are compared with many other methods like simple genetic algorithm (GA), adaptive genetic algorithm (AGA), differential evolution (DE), particle swarm optimization (PSO) and music based harmony search (MBHS) on a IEEE30 bus test bed, with a total load of 283.4 MW. It’s found that the proposed algorithm is found to offer lowest fuel cost. The proposed method is found to be computationally faster, robust, superior and promising form its convergence characteristics. 
Volume: 9
Issue: 2
Page: 211-216
Publish at: 2011-08-01

Combined Scalable Video Coding Method for Wireless Transmission

10.12928/telkomnika.v9i2.700
Kalvein; Institut Teknologi Sepuluh Nopember (ITS), Universitas Nusa Cendana Rantelobo , Wirawan; Institut Teknologi Sepuluh Nopember (ITS) Wirawan , Gamantyo; Institut Teknologi Sepuluh Nopember (ITS) Hendrantoro , Achmad; Institut Teknologi Sepuluh Nopember (ITS) Affandi
Mobile video streaming is one of multimedia services that has developed very rapidly. Recently, bandwidth utilization for wireless transmission is the main problem in the field of multimedia communications. In this research, we offer a combination of scalable methods as the most attractive solution to this problem. Scalable method for wireless communication should adapt to input video sequence. Standard ITU (International Telecommunication Union) - Joint Scalable Video Model (JSVM) is employed to produce combined scalable video coding (CSVC) method that match the required quality of video streaming services for wireless transmission. The investigation in this paper shows that combined scalable technique outperforms the non-scalable one, in using bit rate capacity at certain layer.
Volume: 9
Issue: 2
Page: 295-302
Publish at: 2011-08-01

Implementing the Payment Card Industry (PCI) Data Security Standard (DSS)

10.12928/telkomnika.v9i2.709
Enda; Letterkenny Institute of Technology Bonner , John; Letterkenny Institute of Technology O' Raw , Kevin; University of Ulster Curran
Underpinned by the rise in online criminality, the payment card industry (PCI) data security standards (DSS) were introduced which outlines a subset of the core principals and requirements that must be followed, including precautions relating to the software that processes credit card data. The necessity to implement these requirements in existing software applications can present software owners and developers with a range of issues. We present here a generic solution to the sensitive issue of PCI compliance where aspect orientated programming (AOP) can be applied to meet the requirement of masking the primary account number (PAN).  Our architecture allows a definite amount of code to be added which intercepts all the methods specified in the aspect, regardless of future additions to the system thus reducing the amount of work required to the maintain aspect. We believe that the concepts here will provide an insight into how to approach the PCI requirements to undertake the task. The software artefact should also serve as a guide to developers attempting to implement new applications, where security and design are fundamental elements that should be considered through each phase of the software development lifecycle and not as an afterthought.
Volume: 9
Issue: 2
Page: 365-376
Publish at: 2011-08-01
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