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30,895 Article Results

Influence of Dual-layer and Triple-layer Remote Phosphor Package on Optical Properties of White LEDs

10.12928/telkomnika.v16i5.9505
Nguyen Thi Phuong; Ton Duc Thang University Thao , Nguyen Doan Quoc; Ton Duc Thang University Anh , Kamil; VŠB-Technical University of Ostrava Postava , Miroslav; VŠB-Technical University of Ostrava Voznak , Phan Xuan; HCMC University of Food Industry Le
In this paper, the influence of the distance between phosphor layers in the dual-layer and triple- layer remote package on luminous flux and color rendering property is presented and analyzed. During the simulation, it is recognized that an appropriate distance can produce higher quality of the multi-chip white LED (MCW-LEDs) through adjusting the distance between two and three phosphor layers. According to the research results, 0.1mm is the outstanding distance between two phosphor layers so that the performance of MCW-LEDs can be accomplished the best optimal effect. In addition, the simulation results show that the dual-layer structure yielded higher optical properties than the triple-layer structure in relation to the distance. The highest lumen output of triple layer-structure can be achieved at the distance of 0.6 mm and dual-layer structure is 0.1 mm. Meanwhile, the color rendering index (CRI) changes insignificantly when the distance increases. Triple layer package is not practical for high power white LEDs due to high cost and low conversion efficiency. Dual-layer remote phosphor package with the distance between two phosphor layers of 0.1mm is an optimal structure of LEDs in improving the luminous efficiency and the color quality.
Volume: 16
Issue: 5
Page: 2226-2232
Publish at: 2018-10-01

Calibration of Geomagnetic and Soil Temperatur Sensor for Earthquake Early Warning System

10.12928/telkomnika.v16i5.7592
Dodi Yudo; IIB Darmajaya Setyawan , Dona; IIB Darmajaya Yuliawati , Warsito; Lampung University Warsito , Warsono; Lampung University Warsono
The study of Design of Earthquake Early Warning System for Real Time Using Geomagnetism and Total Electron Content with Fuzzy Logic through competitive grants scheme has obtained the prototype of the earthquake early warning system. However, it still needs improvements on in the calibration of thesensor system especially for MAG3110 sensor and DHT11 sensor. This calibration was done by adjusting the sensor system to the existing measuring devices standards in the Physics Department laboratory of the Sains Faculty Lampung University, to obtain measurement accuracyand to get a good result about where and when the earthquake would occurand how strong the earthquake would be. The calibration of MAG3110 sensor and DHT11 sensor obtained the standard correction results, the standard deviation of MAG3110 from 3 axes, namely x axis was 8.5, y axis was 2.66, and z axis was 1.9, whereas the standard deviation for DH11 sensor was 0.1161.
Volume: 16
Issue: 5
Page: 2239-2244
Publish at: 2018-10-01

Space Charge and Electric Field Analysis on Contaminated XLPE Insulator

10.11591/ijeecs.v12.i1.pp370-377
M.H.A. Wahab , N. A. M. Jamail , E. Sulaiman , Q.E. Kamarudin , N.A. Othman , S.M.N.S. Othman
Nowadays, XLPE cable has been widely used because it has better resistance than other cables. XLPE insulation has unique features including a high dielectric strength and high insulation resistance. A lot of researches based on hardware and software have been conducted to prove the effectiveness of XLPE cable such as AC and DC applications and Space Charge Distribution measurement under HVDC at High Temperature. This research focused on analysis of space charge and electric field on XLPE cable with effect of non-uniform contamination layer by using Quickfield Software. Non-uniform contaminations have been applied along XLPE cable using Arsenic Tribromide (AsBr3), Boron Bromide (BBr3), Ethylene Dichloride (CH2C1), Formic Acid (CH1O2), Formamide (CH3NO) and Alcohol element. Presence of these contamination elements represent of underground contamination. The size and layer of the contamination were non-uniform type. From the results, it is shown that lower dielectric constant of contamination will affect more on charge of XLPE insulation. As a conclusion, it can be seen lower dielectric constant value of contamination element greatly affecting the performance of XLPE insulation. Furthermore, size of contamination also influences the content of charge in contamination where the bigger the contamination size, the more charge contained in the contamination.
Volume: 12
Issue: 1
Page: 370-377
Publish at: 2018-10-01

Control System Based on Fuzzy Logic In Nutmeg Oil Distillation Process

10.12928/telkomnika.v16i5.8350
Syamsul; Politeknik Negeri lhokseumawe Syamsul , Rudi; Politeknik Negeri lhokseumawe Syahputra , Suherman; Politeknik Negeri lhokseumawe Suherman , Zamzami; Politeknik Negeri lhokseumawe Zamzami
The focus of this research is the application of electronic control on the distillation boiler of nutmeg oil. The control system is based on fuzzy logic and as the input parameter is temperature and vapor pressure. The temperature parameters are set in the range 80-120ºC, and the vapor pressure parameters are set in the range of 1-2.5 atmospheres. The output parameter is the time required in the distillation process. The optimal values of these input and output parameters are embedded in microcontroller based control. The control responds to the temperature and vapor pressure to select the gas flow rate at the distillation boiler. This experiment was conducted on a distillation system with a capacity of 25 kg of crushed dried nutmeg, manually and with control based on fuzzy logic. Conventional testing requires 6.90 kg of gas and applying fuzzy logic based control requires 5.50 kg of gas. The yield of nutmeg oil from the distillation process is 2.5 kg conventionally and 2.63 kg with fuzzy logic control. Based on the optimal time of 16 hours distillation process, there was a decrease of gas consumption by 20.3%.
Volume: 16
Issue: 5
Page: 2254-2262
Publish at: 2018-10-01

Threshold Voltage Roll-off by Structural Parameters for Sub-10 nm Asymmetric Double Gate MOSFET

10.12928/telkomnika.v16i5.10248
Hakkee; Kunsan National University Jung
This study is to analyze threshold voltage roll-off according to structural parameters of sub-10 nm asymmetric double gate MOSFET. In case of sub-10nm channel length, because of short channel effects resulting from the rapid increase of tunneling current, even asymmetric double gate (DG) MOSFET, which has been developed for reducing short channel effects, will increase threshold voltage roll-off, and this is an obstacle against the miniaturization of asymmetric DGMOSFET. Especially, since asymmetric DGMOSFET can be produced differently in top and bottom oxide thickness, top/bottom oxide thickness will affect the threshold voltage roll-off. To analyze this, thermal emission current and tunneling current model have been calculated, and threshold voltage roll-off in accordance with the reduction of channel length has been analyzed by using channel thickness and top/bottom oxide thickness as parameters. As a result, it is found that, in short channel asymmetric double gate MOSFET, threshold voltage roll-off is changed greatly according to top/bottom gate oxide thickness, and that threshold voltage roll-off, in particular, is generated more greatly according to silicon thickness. In addition, it is found that top and bottom oxide thickness have a relation of inverse proportion mutually for maintaining identical threshold voltage
Volume: 16
Issue: 5
Page: 2444-2450
Publish at: 2018-10-01

A Miniature L-slot Microstrip Printed Antenna for RFID

10.12928/telkomnika.v16i5.9378
Mohamed; Hassan 1st University Ihamji , El hassane; Hassan 1st University Abdelmounim , Jamal; Hassan 1st University Zbitou , Hamid; Moulay Ismail University Bennis , Mohamed; Microwave Group Latrach
This work presents a miniature microstrip antenna at 2.45 GHz by using the slots technique. This microstrip antenna is fed by a CPW technique and designed for RFID reader system on FR4 substrate. A size reduction equal to 66.6% has been obtained compared to the conventional rectangular microstrip antenna. The total area of the final circuit is 19x31 mm2. The validated antenna has good matching input impedance with a stable radiation pattern, a loss return of -40 dB, and a gain of 1.78 dBi, a prototype of the proposed antenna has been fabricated and measured.
Volume: 16
Issue: 5
Page: 1923-1930
Publish at: 2018-10-01

Load Flow Based Voltage Stability Indices for Voltage Stability and Contingency Analysis for Optimal Location of STATCOM in Distribution Network with Integrated Distributed Generation Unit

10.12928/telkomnika.v16i5.10577
Ibrahim; University Kuala Lumpur British Malaysian Institute (UniKL BMI) Alhamrouni , M. A; University Kuala Lumpur British Malaysian Institute (UniKL BMI) Alif , Bazilah; University Kuala Lumpur British Malaysian Institute (UniKL BMI) Ismail , Mohamed; Universiti Sains Malaysia Salem , Awang; Universiti Teknologi Malaysia Jusoh , T.; Universitas Ahmad Dahlan Sutikno
Electrical power system is growing rapidly with the current increasing demand. One of many important issues being faced in power system is the voltage instability. With that being said, this work investigates the voltage stability indices with contingency analysis used in order to determine the voltage stability of the network system. These approaches are used to detect and avoid voltage instability in the distribution network. The behavior of the distribution network is determined based on the contingency analysis. STATCOM is injected into selected buses in the distribution network of the system to determine the system’s stability during the contingency condition. Distributed generation (DG) is utilized to enhance the network stability. Different scenarios have been assumed in order to test the proposed technique under different conditions. The work has been implemented in Digsilent power factory environment. The proposed technique has been tested on IEEE 30 bus system. Promising results have been obtained with respect to previous published literature, in term of identifying the weak buses and enhancing the overall stability of the network.
Volume: 16
Issue: 5
Page: 2302-2315
Publish at: 2018-10-01

Tropospheric Scintillation with Rain Attenuation of Ku Band at Tropical Region

10.12928/telkomnika.v16i5.10002
Ibtihal F; Universiti Teknologi Malaysia El-shami , Lam Hong; Universiti Teknologi Malaysia Yin , Jafri; Universiti Teknologi Malaysia Din , Ali l; College of Electrical and Electronics Technology Benghazi Elgayar , Manhal; Universiti Teknologi Malaysia Alhilali
Tropospheric scintillation can become a significant impairment in satellite communication systems, especially in tropical regions with frequencies higher than 10 GHz, the attenuation is dramatically affecting the scintillation. This work concentrates on those aspects in equatorial Johor Bahru, Malaysia, based on a one-year Ku-band propagation measurement campaign, utilizing the equipment of Direct Broadcast Receiver (DBR) and Automatic Weather Station (AWS). This study investigates the relationship between wet scintillation and rain attenuation using experimental measurement and concentrate on the probability density function (PDF) of different scintillation parameters. From the results, it is concluded that wet scintillation intensity increases with rain attenuation. Thus, the relationship can be phrased by linear equations or power-law. The PDFs of wet scintillation intensity, adapted to a given rain attenuation level, are found lognormally distributed, leading to selection of method for determining the relation between conditional PDFs and rain attenuation.
Volume: 16
Issue: 5
Page: 1982-1987
Publish at: 2018-10-01

Performance of MPLS-based Virtual Private Networks and Classic Virtual Private Networks Using Advanced Metrics

10.12928/telkomnika.v16i5.7326
Kennedy; Covenant University Okokpujie , Olamilekan; Covenant University Shobayo , Etinosa; Covenant University Noma-Osaghae , Okokpujie; Covenant University Imhade , Obinna; Covenant University Okoyeigbo
Multiprotocol Label Switching (MPLS) is effective in managing and utilizing available network bandwidth. It has advanced security features and a lower time delay. The existing literature has covered the performance of MPLS-based networks in relation to conventional Internet Protocol (IP) networks. But, too few literatures exist on the performance of MPLS-based Virtual Private Networks (VPN) in relation to traditional VPN networks. In this paper, a comparison is made between the effectiveness of the MPLS-VPN network and a classic VPN network using simulation studies done on OPNET®. The performance metrics used to carry out the comparison include; End to End Delay, Voice Packet Sent/Received and Label Switched Path’s Traffic. The simulation study was carried out with Voice over Internet Protocol (VoIP) as the test bed. The result of the study showed that MPLS-based VPN networks outperform classic VPN networks.
Volume: 16
Issue: 5
Page: 2073-2081
Publish at: 2018-10-01

Critical Review of Different Methods for Siting and Sizing Distributed-generators

10.12928/telkomnika.v16i5.9693
Shomefun T; Covenant University S , Ademola; Covenant University A , Awosope CO; Covenant University A , Adekitan A; Covenant University I
Due to several benefits attached to distributed generators such as reduction in line losses, improved voltage profile, reliable system etc., the study on how to optimally site and size distributed generators has been on the increase for more than two decades. This has propelled several researchers to explore various scientific and engineering powerful simulation tools, valid and reliable scientific methods like analytical, meta-heuristic and hybrid methods to optimally place and size distributed generator(s) for optimal benefits. This study gives a critical review of different methods used in siting and sizing distributed generators alongside their results, test systems and gaps in literature.
Volume: 16
Issue: 5
Page: 2395-2405
Publish at: 2018-10-01

Performance Enhancement of MIMO-OFDM using Redundant Residue Number System

10.11591/ijece.v8i5.pp3902-3912
M. I. Youssef , A. E. Emam , M. Abd Elghany
Telecommunication industry requires high capacity networks with high data rates which are achieved through utilization of Multiple-Input-Multiple-Output (MIMO) communication along with Orthogonal Frequency Division Multiplexing (OFDM) system. Still, the communication channel suffers from noise, interference or distortion due to hardware design limitations, and channel environment, and to combat these challenges, and achieve enhanced performance; various error control techniques are implemented to enable the receiver to detect any possible received errors and correct it and thus; for a certain transmitted signal power the system would have lower Bit Error Rate (BER). The provided research focuses on Redundant Residue Number System (RRNS) coding as a Forward Error Correction (FEC) scheme that improves the performance of MIMO-OFDM based wireless communications in comparison with current methods as Low-Density Parity Check (LDPC) coders at the transmitter side or equalizers at receiver side. The Bit Error Rate (BER) performance over the system was measured using MATLAB tool for different simulated channel conditions, including the effect of signal amplitude reduction and multipath delay spreading. Simulation results had shown that RRNS coding scheme provides an enhancement in system performance over conventional error detection and correction coding schemes by utilizing the distinct features of Residue Number System (RNS).
Volume: 8
Issue: 5
Page: 3902-3912
Publish at: 2018-10-01

An Enhancement Role and Attribute Based Access Control Mechanism in Big Data

10.11591/ijece.v8i5.pp3187-3193
M Meneka , K. Meenakshisundaram
To be able to leverage big data to achieve enhanced strategic insight and make informed decision, an efficient access control mechanism is needed for ensuring end to end security of such information asset. Attribute Based Access Control (ABAC), Role Based Access Control (RBAC) and Event Based Access Control (EBAC) are widely used access control mechanisms. The ABAC system is much more complex in terms of policy reviews, hence analyzing the policy and reviewing or changing user permission are quite complex task. RBAC system is labor intensive and time consuming to build a model instance and it lacks flexibility to efficiently adapt to changing user’s, objects and security policies. EBAC model considered only the events to allocate access controls. Yet these mechanisms have limitations and offer feature complimentary to each other. So in this paper, Event-Role-Attribute based fine grained Access Control mechanism is proposed, it provide a flexible boundary which effectively adapt to changing user’s, objects and security policies based on the event. The flexible boundary is achieved by using temporal and environment state of an event. It improves the big data security and overcomes the disadvantages of the ABAC and RBAC mechanisms. The experiments are conducted to prove the effectiveness of the proposed Event-Role-Attribute based Access Control mechanism over ABAC and RBAC in terms of computational overhead.
Volume: 8
Issue: 5
Page: 3187-3193
Publish at: 2018-10-01

About Quality of Optical Channels in Wavelength Division Multiplexing Systems of Optic Fibers

10.12928/telkomnika.v16i5.10300
Mirazimova Gulnora; Tashkent University of Information Technologies Hasanovna
Researches and the analysis of factors of the systems influencing quality with division according to radiation wavelength are given in article. Especially the communication quality in systems with wave division of channels is influenced by hindrances from Four Wave Mixing. In this regard the technique of definition of number of products of nonlinear effect of Four Wave Mixing getting to ranges of working channels, results of calculation of combinational products for the different number of channels in systems with division according to radiation wavelength is given. Power of a hindrance of Four Wave Mixing in systems with wave division of channels is calculated. Methods of reduction of influences of these nonlinear effects are considered. Conclusions and recommendations on ensuring quality of optical channels are provided in systems with wave division.
Volume: 16
Issue: 5
Page: 2005-2013
Publish at: 2018-10-01

A Hardware Model to Measure Motion Estimation with Bit Plane Matching Algorithm

10.12928/telkomnika.v16i5.7672
Shaik Asif; Middle East College Hussain , Chandrashekar; Middle East College Ramaiah , S. Javeed; Sultanate of Oman Hussain
The multistep approach involving combination of techniques is referred as motion estimation. The proposed approach is an adaptive control system to measure the motion from starting point to limit of search. The motion patterns are used to analyze and avoid stationary regions of image. The algorithm proposed is robust efficient and the calculations justify its advantages. The motivation of the work is to maximize the encoding speed and visual quality with the help of motion vector algorithm. In this work a hardware model is developed in which a frame of pictures are captured and sent via serial port to the system. MATLAB simulation tool is used to detect the motion among the picture frame. Once any motion is detected that signal is sent to the hardware which will give the appropriate sign accordingly. This system is developed on two platforms (hardware as well software) to estimate and measure the motion vectors.
Volume: 16
Issue: 5
Page: 2091-2100
Publish at: 2018-10-01

A Comparative Modeling and Analysis of Voltage Variation by Using Spectrogram

10.12928/telkomnika.v16i5.9493
Weihown; Universiti Teknikal Malaysia Melaka (UTeM) Tee , AR; Universiti Teknikal Malaysia Melaka (UTeM) Abdullah , T; Universitas Ahmad Dahlan (UAD) Sutikno , MH; CeRIA, UTeM Jopri , M; CeRIA, UTeM Manap
In this paper, the power quality (PQ) disturbance which is the voltage variations consist of voltage swell, sag and interruption are model and analyze. Different types of voltage variations PQ disturbances models are developed and created by using MATLAB/Simulink as well as mathematical models. The mathematical and Simulink model are used to compare in terms of time-frequency representation (TFR). The Simulink models include shutting down enormouscapacities from system to resemble voltage swell, large loads energizing and three-phase fault to simulate voltage sag as well as implementing permanent three-phase fault to simulate voltage interruption. The signals generated are analyzed by using linear time-frequency distribution (TFD). The signal parameters such as root mean square voltage (Vrms), total harmonic distortion (THD) and power value are estimated from the TFR to identify the characteristics of the voltage variation. The results of analysis on the PQ disturbance waveforms generated are identical to the actual real-time PQ signals and the models can be modified to any desired situation respectively. The PQ waveforms obtained are suitable to be further analyzed.
Volume: 16
Issue: 5
Page: 2385-2394
Publish at: 2018-10-01
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