TELKOMNIKA (Telecommunication Computing Electronics and Control)
Submitted papers are evaluated by anonymous referees by single blind peer review for contribution, originality, relevance, and presentation. The Editor shall inform you of the results of the review as soon as possible, hopefully in 10 weeks. Please notice that because of the great number of submissions that TELKOMNIKA has received during the last few months the duration of the review process can be up to 14 weeks. Communication Engineering, Computer Network and System Engineering, Computer Science and Information System, Machine Learning, AI and Soft Computing, Signal, Image and Video Processing, Electronics Engineering, Electrical Power Engineering, Power Electronics and Drives, Instrumentation and Control Engineering, Internet of Things (IoT)
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Dynamic Evolution Control for Fuel Cell DC-DC Converter
Ahmad Saudi Samosir;
Tole Sutikno;
Abdul Halim Mohd Yatim
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.686
Fuel cells are new alternative energy resource that has a great promise for distributed generation and electric vehicle application. However, fuel cells have a slow response due to their slow internal electromechanical and thermodynamic response. To optimize the fuel cell system performance, a fuel cell DC-DC converter with an appropriate controller which can regulate the power flow and automatically adjust the converter output voltage is needed. This paper proposes a new control technique for fuel cell DC-DC power converter. Design of the proposed control method for fuel cell DC-DC power converter is provided. A new approach for converter controllers synthesis based on dynamic evolution control theory is presented. In this paper, synthesis example of boost DC-DC converter is discussed. Performance of the proposed dynamic evolution control under step load variation condition is simulated under Matlab-Simulink environment. Simulation results show that the proposed techniques are capable for controlling fuel cell DC-DC converter.
Inverse S-Transform Based Decision Tree for Power System Faults Identification
Srikanth Pullabhatla;
Ashwani Kumar Chandel;
Anil Naik Kanasottu
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.674
In this paper a decision tree based identification of power system faults has been proposed. The key input values to the decision tree are the performance indices calculated from the maximum values of unfiltered inverse Stockwell transform (MUNIST) technique. A wide range of techniques including Stockwell transform (ST) have been used for the identification of power system faults. However, the signatures produced by these techniques are not unique and sometimes lead to misinterpretation of faults. Consequently, a decision tree based on the inverse Stockwell transform method is proposed in the present paper to automatically identify both the symmetrical and unsymmetrical power system faults. The method is able to determine both sudden and gradual changes in the signal caused by different power system faults. The technique is very accurate and produces unique signatures compared to the existing techniques. The results obtained show the efficacy of the proposed technique.
Case Study of a Hybrid (Wind and Solar) Power Plant
Sunil M Jaralikar;
Mangalpady Aruna
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.641
The paper highlights the urgency of utilizing and promoting use of non conventional sources, particularly the wind and solar energy, so as to control the environmental pollution, such as ozone layer depletion, deforestation, loss of biodiversity, global warming etc. As a case study, the various performance factors of a 10 kW hybrid (wind and solar) power plant, which is having 60:40 power generation share of wind power to solar power were analysed. The study shows that there is mismatch between the designed and actual plant load factor (PLF), as well as the power generation share of the wind and solar power plant. It was also found that the plant utilization factor (PUF) was poor and that there is very less scope for installation of solar tracking system. Based on the detailed analysis of obtained results, certain recommendations were made for streamlining and optimizing the power generation capacity, and also for better utilization of generated power.
Energy Analysis for Air Conditioning System Using Fuzzy Logic Controller
Henry Nasution;
Hishamuddin Jamaluddin;
Jamaluddin Mohd. Syeriff
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.680
Reducing energy consumption and to ensure thermal comfort are two important considerations for the designing an air conditioning system. An alternative approach to reduce energy consumption proposed in this study is to use a variable speed compressor. The control strategy will be proposed using the fuzzy logic controller (FLC). FLC was developed to imitate the performance of human expert operators by encoding their knowledge in the form of linguistic rules. The system is installed on a thermal environmental room with a data acquisition system to monitor the temperature of the room, coefficient of performance (COP), energy consumption and energy saving. The measurements taken during the two hour experimental periods at 5-minutes interval times for temperature setpoints of 20oC, 22oC and 24oC with internal heat loads 0, 500, 700 and 1000 W. The experimental results indicate that the proposed technique can save energy in comparison with On/Off and proportional-integral-derivative (PID) control.
Power Oscillation Damping Control using Robust Coordinated Smart Devices
Tumiran Tumiran;
Cuk Supriyadi Ali Nandar;
Sarjiya Sarjiya
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.646
The lack of damping of the electromechanical oscillation modes usually causes severe problems of low frequency oscillations in interconnected power systems. In the extreme operating conditions, PSS may fail to damp power oscillation. This paper presents a robust coordinated design of power system stabilizer (PSS) and thyristor controlled series capacitor (TCSC) to damp power oscillation in an interconnected power system. The inverse additive perturbation is applied to represent unstructured uncertainties in the power system such as variations of system parameters, system generating and loading conditions. In addition, genetic algorithm is employed to search a robust tuning to the controller parameters of both PSS and TCSC simultaneously. Simulation studies have been done in a single machine infinite bus system to confirm that the performance and robustness of the proposed controller are superior to that of the conventional controller.
Efficient Motion Field Interpolation Method for Wyner-Ziv Video Coding
I Made Oka Widyantara;
Wirawan Wirawan;
Gamantyo Hendrantoro
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.687
Wyner-Ziv video coding has the capability to reduce video encoding complexity by shifting motion estimation procedure from encoder to decoder. Amongst many motion estimation methods, expectation maximization algorithm is the most effective one. Unfortunately, the implementation of block-based motion estimation in this algorithm causes motion field profile bounded by granularity of block size. Nearest-neighbor and bilinear interpolation methods have already applied in multiview image coding to handle similar problem. This paper aims to evaluate performance of both interpolation methods in transform-domain Wyner-Ziv video codec. Results showed that bilinear interpolation effective only for high motion video sequences. In this scenario, it has bitrate saving up to 3.29 %, 0.2 dB higher PSNR, and 12.30 % higher decoding complexity compared to nearest-neighbor. In low motion video content, bitrate saving only gained up to 0.82%, with almost the same PSNR, while decoding complexity increase up to 10.32%.
Removal of Interferences from Partial Discharge Pulses using Wavelet Transform
Vidya H.A Vidya H.A;
Bindia Tyagi;
V Krishnan V Krishnan;
K. Mallikarjunappa K. Mallikarjunappa
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.675
It is essential to detect partial discharge (PD) as a symptom of insulation breakdown in high voltage (HV) applications. However accuracy of such measurement is often degraded due to the existence of noise in the signal. Wavelet Transform (WT) seems to be more suitable than traditional Fourier Transform in analyzing signals with interesting transient information such as partial discharge (PD) signals. In this paper a WT method with soft thresholding is used for signal denoising. PD signals and corona obtained from actual measurements with different voltage magnitudes are processed. Processed signals show the better result.
Plastic Ball Grid Array Encapsulation Process Simulation on Rheology Effect
Dadan Ramdan;
Mohd Zulkifly Abdullah;
Khor Chu Yee
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.642
The integrated circuit should be encapsulated for protection from their intended environment. This paper presents the flow visualization of the plastic ball grid array (PBGA) chip encapsulation process considering of the rheology effect. In the molding process, encapsulant flow behavior is modeled by Castro-Macosko viscosity model with considering curing effect and volume of fluid technique is applied for melt front tracking. The viscosity model is written into C language and compiled using User-Defined Functions into the FLUENT analysis. Three types of Epoxy Molding Compound namely case 1, 2, and 3 were utilized for the study of fluid flow inside the mold cavity. The melt front profiles and viscosity versus shear rate for all cases are analyzed and presented. The numerical results are compared with the previous experimental results and found in good conformity. In the present study, case 1 with greater viscosity shows the higher air trap and higher pressure distributions.
Partial Discharge Phase Distribution of Palm Oil as Insulating Liquid
Abdul Rajab;
Umar K. Umar K.;
D. Hamdani D. Hamdani;
Aminuddin S. Aminuddin S.;
Suwarno Suwarno;
Y. Abe Y. Abe;
M. Tsuchie M. Tsuchie;
M. Kozako M. Kozako;
S. Ohtsuka S. Ohtsuka;
M. Hikita M. Hikita
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.683
Due to the low biodegradability level of mineral oil and its susceptibility to the fire, palm oil was proposed as alternative insulating liquid. This paper discusses partial discharge (PD) in palm oil under sinusoidal voltages and the comparison with mineral oil. PD was generated using a needle-plane electrode configuration which is enable enhancing electric field at the needle tip. PD pulses were detected using RC detector and they were measured using a Computer-based partial discharge measurement system. The results showed that PD activities in both oils are similar. The PD was initiated at the negative polarity of applied voltage. The discharges took place in both polarity’s of applied voltage with PD number was higher at negative one. Several discharges phenomena showed the presence of space charge which changed electric field and governed PD activities besides the main field introduced by voltage application.
Curtailed-Gaussian and Cosine Functions for Multihop Doppler Spectrum Modeling
Titiek Suryani;
Gamantyo Hendrantoro
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 9, No 1: April 2011
Publisher : Universitas Ahmad Dahlan
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DOI: 10.12928/telkomnika.v9i1.671
Wireless channels are characterized among others by their Doppler spectrum. In the cooperative diversity, one of diversity branch may consist of several mobile relays forming multihop link which each hop introduced Doppler shift. With employing amplify-and-forward (AF) relays, the Doppler shift keeps accumulating to the end of the link. Doppler shift value affects the time varying channel rate, which is a challenge in broadband mobile communication system. Hence, the Doppler parameter is very important and must be considered in broadband mobile communication system design and analysis. Unfortunately, it is hard to derive the expressions of this Doppler spectrum in a closed form since a special function under integration such as complete elliptic integral exists. To solve this problem, curve-fitting method base on least-square is used. In this process, curtailed-Gaussian and cosine functions are proposed as an approximation function. Then, from Kullback-Leiber divergence test, it is showed that both proposed functions, i.e., curtailed-Gaussian and cosine functions have a good approximation as Doppler spectrum modeling of Multihop mobile channel with all gain relays assumed as 1 and all mobile terminals are assumed move with almost same velocity.