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26,833 Article Results

Malicious User Attack in Cognitive Radio Networks

10.12928/telkomnika.v15i3.5794
N.; Jazan Universit Armi , S.; Bahria University Rizvi , W.Z.; Jazan University Khan , H.; Jazan University Zangoti , W.; Jazan University Gharibi , C.; Indonesian Institute of Sciences Wael
Signal detection in cognitive radio network (CRN) is influenced by several factors. One of them is malicious user that emulate primary user (PU) signal. Emulation of PU signal causes detection error. This paper investigates the impact of malicious user attack to PU signal detection. A number of malicious users are randomly deployed around secondary user (SU) at a certain distance. They attempt to attack primary signal detection that is transmitted from 100 km to SU receiver. Then, the received signal power at secondary receiver and the performance of probability of false alarm and probability of miss detection under two hypothesis of Neyman Pearson criterion are studied. The derived results show that a number of malicious users has a significant impact to the performance of received power at SU and detection error rate.
Volume: 15
Issue: 3
Page: 1096-1102
Publish at: 2017-09-01

Enhancing the LVRT Capability and Mitigation of Power Quality Issues Using UPQC of a Grid Connected Wind Conversion System

10.11591/ijeecs.v7.i3.pp643-654
C.S Boopathi , Kuppusamy Selvakumar , Avisek Dutta
In this paper unified power quality conditioner has been used to enhance low voltage ride through capability of grid connected wind conversion system taking Doubly fed induction generator (DFIG). Unified Power quality conditioner (UPQC) device is a combination of series active filter and shunt active filter. This custom power device is mainly used to mitigate power quality issues which is an essential factor today because of wide application of power electronics devices. UPQC is capable to deal with voltage and current imperfection simultaneously. It is installed in the system mainly to improve the power quality i.e. Voltage sag/swell, Harmonics, reactive power compensation etc. at point of common coupling. System is modeled in MATLAB/SIMULINK and results shows utilization of UPQC for the enhancement of LVRT of a DFIG wind system according to Grid code. when fault occurs in the system, it will create voltage dip and series compensator of UPQC injects during this time to prevent disconnection from grid and stay connected to contribute during fault. UPQC is also used for fast restoration of system steady state, power factor improvement, prevent rotor over current.
Volume: 7
Issue: 3
Page: 643-654
Publish at: 2017-09-01

Step-Function Approach for E-Learning Personalization

10.12928/telkomnika.v15i3.4457
Sfenrianto; Binus University Sfenrianto , Zainal; Universitas Indonesia A. Hasibuan
Personalization is an alternative to improve the learning process for an e-Learning environment. It is a useful strategy to adjust the student' needs based on their characteristics to make learning more effectively. In this study, we propose the step-function approach for personalization in e-learning. It provides the students with adopting the knowledge-ability factor (Novice, Average, or Good category) that matches with their learning materials levels (Level1, Level2, or Level3). The approach implemented into an e-learning which called SCELE-PDE and used as the experimental group in two stages with different scenarios. In the first, without a step-function approach, but the SCELE-PDE can identify an initial of student's ability to knowledge category. The second stage has used the approach to providing students with personalization in e-Learning to adapt learning material based on a knowledge category. As a result, the step-function approach has successfully to improve the student performance in the learning process during the course. Thus, the approach has shown an increase in the level of students’ knowledge. So, it can be used as a guide when designing an e-learning personalization for students to enhance learning and achievement.
Volume: 15
Issue: 3
Page: 1362-1367
Publish at: 2017-09-01

Bandwidth and Gain Enhancement of MIMO Antenna by Using Ring and Circular Parasitic with Air-Gap Microstrip Structure

10.12928/telkomnika.v15i3.6377
Teguh; Department of Electrical Engineering, University of Sultan Ageng Tirtayasa Firmansyah , Herudin; Department of Electrical Engineering, University of Sultan Ageng Tirtayasa Herudin , Suhendar; Department of Electrical Engineering, University of Sultan Ageng Tirtayasa Suhendar , Romi; Department of Electrical Engineering, University of Sultan Ageng Tirtayasa Wiryadinata , M Iman; Department of Electrical Engineering, University of Sultan Ageng Tirtayasa Santoso , Yus Rama; Department of Physics Education, University of Sultan Ageng Tirtayasa. Denny , Toto; Department of Electrical Engineering, Jakarta State Polytechnic Supriyanto
This research was proposed a circular patch MIMO antenna by using a ring and circular parasitic radiator structure. As a novelty, in order to enhance bandwidth and gain of circular patch MIMO antenna, a conventional circular patch MIMO antenna will be added a ring and a circular parasitic. Therefore, this research was investigated a conventional MIMO antenna (C-MA), ring parasitic MIMO antenna (RP-MA), and circular parasitic MIMO antenna (CP-MA) as Model 1, Model 2, and Model 3, respectively. This MIMO antenna was designed on FR4 microstrip substrate with r= 4.4, thickness h=1.6 mm, and tan = 0.0265. This MIMO antenna has center frequency 2.35 GHz which is a frequency band for LTE application in Indonesia. An Advance Design System (ADS) software was used to determine the antenna parameters. The MIMO antenna C-MA / RP-MA/ CP-MA achieves 2.36GHz/ 2.38GHz/ 2.38 GHz, 70 MHz/ 100 MHz/ 120 MHz, 1.625 dBi/ 4.066 dBi/ 4.117 dBi, 6.414 dBi/ 7.26 dBi/ 7.153 dBi, 33.9 %/ 47.8 %/ 49.70 %, -12.35 dB/ -22.21 dB/ -23.66 dB, and -30.924 dB/ -28.46 dB/ -27.59 dB for center frequency, bandwidth, gain, directivity, efficiency, reflection coefficient, and mutual coupling, respectively. Compared to C-MA (Model1) performances, The result showed that proposed antenna has wider-bandwidth/ higher-gain with 42.8%/ 150.2 %, and 71.4%/ 163.3% for RP-MA (Model 2) and CP-MA (Model 3), respectively. The proposed antenna has size of 50 mm x 130 mm x 23.2 mm. Measured results are in a good agreement with the simulated results.
Volume: 15
Issue: 3
Page: 1155-1163
Publish at: 2017-09-01

Feature Extraction of Musical Instrument Tones using FFT and Segment Averaging

10.12928/telkomnika.v15i3.3381
Linggo; Sanata Dharma University Sumarno , I.; Sanata Dharma University Iswanjono
A feature extraction for musical instrument tones that based on a transform domain approach was proposed in this paper. The aim of the proposed feature extraction was to get the lower feature extraction coefficients. In general, the proposed feature extraction was carried out as follow. Firstly, the input signal was transformed using FFT (Fast Fourier Transform). Secondly, the left half of the transformed signal was divided into a number of segments. Finally, the averaging results of that segments, was the feature extraction of the input signal. Based on the test results, the proposed feature extraction was highly efficient for the tones, which have many significant local peaks in the Fourier transform domain, because it only required at least four feature extraction coefficients, in order to represent every tone.
Volume: 15
Issue: 3
Page: 1280-1289
Publish at: 2017-09-01

The Correlation of Statistical Image and Partial Discharge Pulse Count of LDPE-NR Composite

10.12928/telkomnika.v15i3.5149
Aulia; Teknik Elektro, Fakultas Teknik, Universitas Andalas, Padang Aulia , Zulkarnain Abdul; UTM Institute of High Voltage & High Current (IVAT)/UTM Highvoltage Malek , Yanuar Zulardiansyah; UTM Institute of High Voltage & High Current (IVAT)/UTM Highvoltage Arief , Eka Putra; Teknik Elektro, Fakultas Teknik, Universitas Andalas, Padang Waldi
High voltage insulation must be designed in such a way that it is very resistant to ageing including that from partial discharge (PD). Many studies were previously carried out on composites based on low density polyethylene (LDPE). However, the use of natural rubber (NR) and nanosilica (SiO2) in the LDPE-NR based composites is relatively new. Furthermore, the PD resistant performance of the composites is yet to be extensively researched. This work aims to analyze the correlation between PD pulse count and its related image to interpreting the effect of PD signals. The results show there is a strong correlation between PD pulse count and the statistical image. The results indicate that the surface image statistical analysis can be used as a tool to justify the total of the PD pulse count on the surface for different samples of composite.
Volume: 15
Issue: 3
Page: 977-983
Publish at: 2017-09-01

A Mathematical Approach for Hidden Node Problem in Cognitive Radio Networks

10.12928/telkomnika.v15i3.6897
Felix; Universiti Teknologi Malaysia Ahmadu Bello University, Zaria, Nigeria Obite , Kamaludin; Universiti Teknologi Malaysia Mohammad Yusof , Jafri; Universiti Teknologi Malaysia Din
Cognitive radio (CR) technology has emerged as a realistic solution to the spectrum scarcity problem in present day wireless networks. A major challenge in CR radio networks is the hidden node problem, which is the inability of the CR nodes to detect the primary user. This paper proposes energy detector-based distributed sequential cooperative spectrum sensing over Nakagami-m fading, as a tool to solve the hidden node problem. The derivation of energy detection performance over Nakagami-m fading channel is presented. Since the observation represents a random variable, likelihood ratio test (LRT) is known to be optimal in this type of detection problem. The LRT is implemented using the Neyman-Pearson Criterion (maximizing the probability of detection but at a constraint of false alarm probability). The performance of the proposed method has been evaluated both by numerical analysis and simulations. The effect of cooperation among a group of CR nodes and system parameters such as SNR, detection threshold and number of samples per CR nodes is investigated. Results show improved detection performance by implementing the proposed model.
Volume: 15
Issue: 3
Page: 1127-1136
Publish at: 2017-09-01

Histogram Equalization for Improving Quality of Low-resolution Ultrasonography Images

10.12928/telkomnika.v15i3.5537
Retno; Jenderal Soedirman University Supriyanti , Subkhi; Jenderal Soedirman University Adhi Priyono , Eko; Jenderal Soedirman University Murdyantoro , Haris; Jenderal Soedirman University Budi Widodo
The current development of digital image processing techniques have been very rapid. Application of digital image processing both hardware and software are available with a variety of features as a form of superiority. Medical ultrasonography is one of the results of digital image processing technology. It is a kind of diagnostic imaging technique with ultrasonic that is used to produce images of internal organs and muscles, size, structure, and wound pathology, which makes this technique is useful for checking organ. However the images produced by low resolution ultrasonography device is not fully produce clear information. In this research we use histogram equalization to improve image quality. In this paper we emphasize on the comparison of the two methods in the histogram equalization, namely Enhance Contrast Using Histogram Equalization (ECHE) and Contrast-Limited Adaptive Histogram Equalization (CLAHE). The results showed that CLAHE give the best results, with the parameter value Nbins 256 and Distribution Rayleigh with MSE value 9744.80 and PSNR value 8.284150.
Volume: 15
Issue: 3
Page: 1397–1408
Publish at: 2017-09-01

Integrated Open Loop Resonator Filter Designed with Notch Patch Antenna for Microwave Applications

10.12928/telkomnika.v15i3.7218
D.; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering Azra Awang Mat , N.; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering Syuhada Hasim , Nurmiza; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering Othman , Amira; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering Amran , D.; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering Norkhairunnisa Abang Zaidel , A.; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering S. Wani Marzuki , Shafrida; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering Sahrani , Kismet; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering anak Hong Ping , Rohana; Applied Electromagnetic Research Group Department of Electrical and Electronic Engineering Sapawi
This paper presented the design of integrated open loop resonator bandpass filter with notch type antenna for the use in microwave applications. Chebyshev type filter is selected as the filter characteristics and cascaded design with the antenna to produce a single module, Integrated Filter Antenna (IFA). Special feature of the antenna is the implementation of notch on the patch antenna to improve the efficiency. IFA is then simulated in electromagnetic simulation tool, Agilent Advance Design System (ADS) version 2016 and measured using R&S Vector Network Analyzer. It shows that the proposed IFA produced good measured return loss >-30dB with both vertical and horizontal gain of 9.11dBi and 8.01dBi respectively.
Volume: 15
Issue: 3
Page: 1485-1492
Publish at: 2017-09-01

Regression Modelling for Precipitation Prediction Using Genetic Algorithms

10.12928/telkomnika.v15i3.4028
Asyrofa; Universitas Brawijaya Rahmi , Wayan Firdaus; Universitas Brawijaya Mahmudy
This paper discusses the formation of an appropriate regression model in precipitation prediction. Precipitation prediction has a major influence to multiply the agricultural production of potatoes in Tengger, East Java, Indonesia. Periodically, the precipitation has non-linear patterns. By using a non-linear approach, the prediction of precipitation produces more accurate results. Genetic algorithm (GA) functioning chooses precipitation period which forms the best model. To prevent early convergence, testing the best combination value of crossover rate and mutation rate is done. To test the accuracy of the predicted results are used Root Mean Square Error (RMSE) as a benchmark. Based on the RMSE value of each method on every location, prediction using GA-Non-Linear Regression is better than Fuzzy Tsukamoto for each location. Compared to Generalized Space-Time Autoregressive-Seemingly Unrelated Regression (GSTAR-SUR), precipitation prediction using GA is better. This has been proved that for 3 locations GA is superior and on 1 location, GA has the least value of deviation level.
Volume: 15
Issue: 3
Page: 1290-1300
Publish at: 2017-09-01

Improving Posture Accuracy of Non-Holonomic Mobile Robot System with Variable Universe of Discourse

10.12928/telkomnika.v15i3.6078
Siti; Universitas Sriwijaya Nurmaini , Bambang; Universitas Sriwijaya Tutuko , Kemala; Universitas Sriwijaya Dewi , Velia; Universitas Sriwijaya Yuliza , Tresna; Politeknik Negeri Sriwijaya Dewi
This paper presents a method to decrease imprecision and inaccuracy that have the tendency to influence the posture of non-holonomic mobile by using the adaptive tuning of universe of discourse. As such, the primary objective of the study is to force the posture error of x(t), y(t) and θ(t) towards zero. Hence, for each step of tuning the fuzzy domain, about 20% of imprecision and inaccuracy had been added automatically into the variable universe fuzzy, while the control input was bound via scaling gain. Furthermore, the experimental results showed that the tuning of universe fuzzy parameters could increase the performance of the system from the aspects of response time and error for steady state through better control of inaccuracy. Besides, the domains of universe fuzzy input [-4,4] and output [0,6] exhibited good performance in inching towards zero values as the steady state error was about 1% for x(t) position, 0.02% for y(t) position, and 0.16% for θ(t) orientation, whereas the posture error in the given reference was about 0.0002%.
Volume: 15
Issue: 3
Page: 1265-1279
Publish at: 2017-09-01

Packet Loss Rate Differentiation in slotted Optical Packet Switching OCDM/WDM

10.12928/telkomnika.v15i3.5019
Omar; Universiti Sains Islam Malaysia Najah , Kamaruzzaman; Universiti Sains Islam Malaysia Seman , Khairi; Universiti Sains Islam Malaysia Abdulrahim
We propose a multi-class mechanism for Optical Code Division Multiplexing (OCDM), Wavelength Division Multiplexing (WDM) Optical Packet Switch (OPS) architecture capable of supporting Quality of Service (QoS) transmission. OCDM/WDM has been proposed as a competitive hybrid switching technology to support the next generation optical Internet. This paper addresses performance issues in the slotted OPS networks and proposed four differentiation schemes to support Quality of Service. In addition, we present a comparison between the proposed schemes as well as, a simulation scheduler design which can be suitable for the core switch node in OPS networks. Using software simulations the performance of our algorithm in terms of losing probability, the packet delay, and scalability is evaluated.
Volume: 15
Issue: 3
Page: 1061-1071
Publish at: 2017-09-01

Using SVD and DWT Based Steganography to Enhance the Security of Watermarked Fingerprint Images

10.12928/telkomnika.v15i3.6437
Mandy; Institute of Technology Letterkenny Douglas , Karen; Institute of Technology Letterkenny Bailey , Mark; Institute of Technology Letterkenny Leeney , Kevin; Ulster University Curran
Watermarking is the process of embedding information into a carrier file for the protection of ownership/copyright of digital media, whilst steganography is the art of hiding information. This paper presents, a hybrid steganographic watermarking algorithm based on Discrete Wavelet Transform (DWT) and Singular Value Decomposition (SVD) transforms in order to enhance the security of digital fingerprint images. A facial watermark is embedded into fingerprint image using a method of singular value replacement. First, the DWT is used to decompose the fingerprint image from the spatial domain to the frequency domain and then the facial watermark is embedded in singular values (SV’s) obtained by application of SVD. In addition, the original fingerprint image is not required to extract the watermark. Experimental results provided demonstrate the methods robustness to image degradation and common signal processing attacks, such as histogram and filtering, noise addition, JPEG and JPEG2000 compression with various levels of quality.
Volume: 15
Issue: 3
Page: 1368-1379
Publish at: 2017-09-01

Brown’s Weighted Exponential Moving Average Implementation in Forex Forecasting

10.12928/telkomnika.v15i3.5410
Seng; Universitas Multimedia Nusantara Hansun , Subanar; Universitas Gadjah Mada Subanar
In 2016, a time series forecasting technique which combined the weighting factor calculation formula found in weighted moving average with Brown’s double exponential smoothing procedures had been introduced. The technique is known as Brown’s weighted exponential moving average (B-WEMA), as a new variant of double exponential smoothing method which does the exponential filter processes twice. In this research, we will try to implement the new method to forecast some foreign exchange, or known as forex data, including EUR/USD, AUD/USD, GBP/USD, USD/JPY, and EUR/JPY data. The time series data forecasting results using B-WEMA then be compared with other conventional and hybrid moving average methods, such as weighted moving average (WMA), exponential moving average (EMA), and Brown’s double exponential smoothing (B-DES). The comparison results show that B-WEMA has a better accuracy level than other forecasting methods used in this research.
Volume: 15
Issue: 3
Page: 1425–1432
Publish at: 2017-09-01

An Upgraded Transverse Electromagnetic Parallel Plates for Dielectric Measurement

10.12928/telkomnika.v15i3.7213
S.; Universiti Tun Hussein Onn Malaysia K. Yee , R.; Universiti Tun Hussein Onn Malaysia Padu , C.; Universiti Tun Hussein Onn Malaysia K. Sia , X.; Universiti Tun Hussein Onn Malaysia T. I. Ngu , S.; Universiti Tun Hussein Onn Malaysia H. Dahlan , M.; Universiti Tun Hussein Onn Malaysia A. Azlan
A new version of transverse electromagnetic parallel plates with irregular plates’ width and plate separation has been developed for dielectric measurement. The separations between the plates are supported by four rectangular Teflon block and 1 mm of groove is proposed at the center of the upper plate to maintain the measurement repeatability. The groove enables the samples which are slightly higher than 2 cm to be fitted well between the plates without introducing extra force to the plates. Theperformance of both parallel plates has been compared in the frequency range from 100 MHz to 1.1 GHz. It is found that the upgraded parallel plate offers better return loss and insertion loss above 500 MHz compared to the previous parallel plate. It is reported from this work that the return loss of the parallel plate must be lower than -15 dB in order to achieve accurate dielectric constant. However, the insertion loss of the parallel plates does not influence the real permeability significantly. The upgraded TEM parallel plateproduces a consistent reading with a standard deviation of less than 0.05 above frequency 200 MHz. The dielectric measurement of Polypropylene (PP) has proven the capability of this upgraded TEM parallelplate.
Volume: 15
Issue: 3
Page: 1446-1453
Publish at: 2017-09-01
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