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28,188 Article Results

The Performance of an Integrated Transformer in a DC/DC Converter

10.12928/telkomnika.v15i3.4251
Abdelhadi; USTO-MB University Namoune , Azzedine; USTO-MB University Hamid , Rachid; Hassiba Benbouali University Taleb
The separation between the low-voltage part and high-voltage part of the converter is formed by a transformer that transfers power while jamming the DC ring. The resonant mode power oscillator is utilized to allow elevated competence power transfer. The on-chip transformer is probable to have elevated value inductance, elevated quality factors and elevated coupling coefficient to decrease the loss in the oscillation. The performance of a transformer is extremely dependent on the structure, topology and other essential structures that create it compatible with the integrated circuits IC process such as patterned ground shield (PGS). Different types of transformers are modeled and simulated in MATLAB; the performances are compared to select the optimum design. The on-chip transformer model is simulated and the Results of MATLAB simulation are exposed, showing an excellent agreement in radio frequency RF.
Volume: 15
Issue: 3
Page: 1031-1039
Publish at: 2017-09-01

Multi-Operator Genetic Algorithm for Dynamic Optimization Problems

10.11591/ijai.v6.i3.pp139-142
Al-khafaji Amen
Maintaining population diversity is the most notable challenge in solving dynamic optimization problems (DOPs). Therefore, the objective of an efficient dynamic optimization algorithm is to track the optimum in these uncertain environments, and to locate the best solution. In this work, we propose a framework that is based on multi operators embedded in genetic algorithms (GA) and these operators are heuristic and arithmetic crossovers operators. The rationale behind this is to address the convergence problem and to maintain the diversity. The performance of the proposed framework is tested on the well-known dynamic optimization functions i.e., OneMax, Plateau, Royal Road and Deceptive. Empirical results show the superiority of the proposed algorithm when compared to state-of-the-art algorithms from the literature.
Volume: 6
Issue: 3
Page: 139-142
Publish at: 2017-09-01

Fuzzy Logic Implementation with MATLAB for PV-Wind Hybrid System

10.12928/telkomnika.v15i3.6099
Alias; Universiti Teknikal Malaysia Melaka Khamis , Mohd Ruddin; Universiti Teknikal Malaysia Melaka Ab. Ghani , Chin Kim; Universiti Teknikal Malaysia Melaka Gan , Mohd Shahrieel; Universiti Teknikal Malaysia Melaka Mohd Aras , Muhamad Fiqry; Universiti Teknikal Malaysia Melaka Khamis , Tole; Universitas Ahmad Dahlan Sutikno , Jano; Universiti Teknikal Malaysia Melaka Zanariah
This paper is under in-depth investigation due to suspicion of possible plagiarism on a high similarity indexThe development of hybrid renewable energy sources is vital in power generation. This study focused on design of fuzzy logic control on hybrid PV/Wind system in order to improve the speed of DC motor. The fuzzy logic control based on battery management system has been designed for effective power utilization and improvement of the DC motor speed performance. In battery management system, a control was proposed to operate the charging and discharging mode of battery during non-linear power generation. While the battery would charge whenever the renewable energy power was greater than consumer load power, the battery would discharge whenever the renewable energy power was less than the consumer load power. DC motor speed control, included the simulation, implementation of fuzzy logic controller to DC motor and comparison between PID controller and Fuzzy Logic Controller. The proposed model was simulated using Matlab environment and the results was analyzed. Finally, simulation results were evaluated and validated to determine the effectiveness of the proposed controller.
Volume: 15
Issue: 3
Page: 1181-1191
Publish at: 2017-09-01

Online Monitoring of Grid Connected Residential Photovoltaic System using Zigbee and Web Server

10.11591/ijeecs.v7.i3.pp668-675
Syafii Ghazali , Roni Putra , Hasdi Putra
The paper presents grid-tied PV monitoring system using wireless sensor networks.  The temperature and humidity parameters were measured using DHT22. While ACS 712 5A current sensor and Arduino voltage sensor modules were used to measure photovoltaic output current and voltage respectively. Web application has been developed in the base station using PHP programming web server to access the sensor nodes through Zigbee wireless data communication. The user can access the HTML web interface of Photovoltaic monitoring system through local Ethernet or Wi-Fi connection. The residential 1.25 kWp grid connected photovoltaic system used to test the developed monitoring system. The data received exactly same as data sensed from remote area with average delay time 3 to 4 seconds. The result shows the photovoltaic power generation caracteristics under clear sky, cloud cover, and rainy weather conditions. The power 608.12 Wp has been generated by the solar panel from 7.00 am to 6.00 pm or 6.7 kWh per day during clear sky. During intermittent cloud covered the photovoltaic power graph have shown fluctuation power profile and energy conversion were decreased as well as in raining weather condition. The electrical power has been generated by photovoltaic for almost 12 hours per day in tropics area, but energy conversion is highly influenced by weather conditions, especially cloud cover, overcast and rainy.
Volume: 7
Issue: 3
Page: 668-675
Publish at: 2017-09-01

A Novel Space-time Discontinuous Galerkin Method for Solving of One-dimensional Electromagnetic Wave Propagations

10.12928/telkomnika.v15i3.5080
Pranowo; Teknik Informatika Universitas Atma Jaya Yogyakarta Pranowo
In this paper we propose a high-order space-time discontinuous Galerkin (STDG) method for solving of one-dimensional electromagnetic wave propagations in homogeneous medium. The STDG method uses finite element Discontinuous Galerkin discretizations in spatial and temporal domain simultaneously with high order piecewise Jacobi polynomial as the basis functions. The algebraic equations are solved using Block Gauss-Seidel iteratively in each time step. The STDG method is unconditionally stable, so the CFL number can be chosen arbitrarily. Numerical examples show that the proposed STDG method is of exponentially accuracy in time.
Volume: 15
Issue: 3
Page: 1310-1316
Publish at: 2017-09-01

Planar Microwave Sensors for Accurate Measurement of Material Characterization: A Review

10.12928/telkomnika.v15i3.6684
Norhanani; Universiti Teknikal Malaysia Melaka Abd Rahman , Zahriladha; Universiti Teknikal Malaysia Melaka Zakaria , Rosemizi; University Malaysia Perlis Abd Rahim , Yosza; Universiti Teknikal Malaysia Melaka Dasril , Amyrul Azuan; Universiti Teknikal Malaysia Melaka Mohd Bahar
Microwave sensor is used in various industrial applications and requires highly accurate measurements for material properties. Conventionally, cavity waveguide perturbation, free-space transmission, open-ended coaxial probe, and planar transmission line technique have been used for characterizing materials. However, these planar transmission lines are often large and expensive to build, further restricting their use in many important applications. Thus, this technique is cost effective, easy to manufacture and due to its compact size, it has the potential to produce sensitivity and a high Q-factor for various materials. This paper reviews the common characteristics of planar transmission line and discusses numerous studies about several designs of the microstrip resonator to improve the sensor performance in terms of the sensitivity and accuracy. This technique enables its use for several industrial applications such as agriculture and quality control. It is believed that previous studies would lead to a promising solution of characterizing materials with high sensitivity, particularly in determining a high Q-factor resonator sensor.
Volume: 15
Issue: 3
Page: 1108-1118
Publish at: 2017-09-01

Design of Circular Patch with Double C-Shaped Slot Microstrip Antenna for LTE 1800 MHz

10.12928/telkomnika.v15i3.5492
Yusnita; Universitas Riau Rahayu , Jherino Permana; Universitas Riau Putra
The design of a circular patch microstrip antenna with double C-shaped for LTE 1800 MHz is presented. The antenna is designed using FR-4 with dielectric constant of ε = 4.3, with thickness of substrate that is 1.6 mm and the thickness of patch and ground are 0.025 mm, Respectively the simulation results presented that the antenna works at frequency of 1714-1889.6 MHz, and work very well at frequency of 1800 MHz with a Return loss -20.484 dB, bandwidth 175.6 MHz. Technique used for broaden the bandwidth by using double C-shaped slot. In this paper presents S-Parameters, and Gain of microstrip antenna circular patch with double C-shaped slot.
Volume: 15
Issue: 3
Page: 1079-1082
Publish at: 2017-09-01

Numerical Simulation of Highly-Nonlinear Dispersion-Shifted Fiber Optical Parametric Gain Spectrum with Fiber Loss and Higher-Order Dispersion Coefficients

10.12928/telkomnika.v15i3.7215
K.; Universiti Tun Hussein Onn Malaysia G. Tay , N.; Universiti Tun Hussein Onn Malaysia Othman , N.; Universiti Tun Hussein Onn Malaysia S. M. Shah , N.; Universiti Tun Hussein Onn Malaysia A. Cholan
The previous study investigated the fiber parameters on the analytical one-pump fiber optical parametric amplifier (FOPA) gain spectrum of a loss-free highly-nonlinear dispersion-shifted fiber (HNL-DSF) and got the optimum results for each parameter. However, the FOPA gain of the combination of all the optimum values of the considered parameters was not reported. Hence, this paper intends to investigate the analytical FOPA gain of the combination of all the optimum values of the considered parameters from the previousstudy. Later, the analytical gain was compared with the numerical gain from the fourth-order Runge-Kutta (RK4) method and Matlab built-in function, ode45. Next, the effect of fiber loss and higher order dispersioncoefficients such as fourth and sixth-order dispersion coefficients were studied. It is found that RK4 gives a smaller error and the gain reduces while the bandwidth remains same in presence of fiber loss. Thefourth-order dispersion coefficient broadens the bandwidth a bit while maintaining the gain and there are two narrow-band gains generated to the left and right-side of the broad-band gain. The sixth-order dispersioncoefficient just shifts the two narrow-band gains toward or away from the broadband gain depending on the positive or negative signs of the sixth-order dispersion coefficient.
Volume: 15
Issue: 3
Page: 1461-1469
Publish at: 2017-09-01

Analysis of Memory Effects in Digital Filters with Overflow Arithmetic

10.11591/ijeecs.v7.i3.pp755-760
Mani Kant Kumar , Haranath Kar
This paper deals with the problem of undesired memory effects in nonlinear digitalfilters owing to the influence of past excitations on future outputs. The nonlinearities under consideration cover the usual types of overflow arithmetic employed in practice. Based on the Hankel norm performance, a new criterion is proposed to ensure the reduction of undesired memory effects in digital filters with overflow arithmetic. In absence of external input, the nonexistence of overflow oscillations is also confirmed by the proposed criterion. A numerical example together with simulation result showing the effectiveness of the criterion is given.
Volume: 7
Issue: 3
Page: 755-760
Publish at: 2017-09-01

Decision Support System for Bat Identification using Random Forest and C5.0

10.12928/telkomnika.v15i3.3638
Deden Sumirat; Bogor Agricultural University ; Research Center for Biology-LIPI Hidayat , Imas Sukaesih; Bogor Agricultural University Sitanggang , Gono; Research Center for Biology-LIPI Semiadi
Morphometric and morphological bat identification are a conventional method of identification and requires precision, significant experience, and encyclopedic knowledge. Morphological features of a species may sometimes similar to that of another species and this causes several problems for the beginners working with bat taxonomy. The purpose of the study was to implement and conduct the random forest and C5.0 algorithm analysis in order to decide characteristics and carry out identification of bat species. It also aims at developing supporting decision-making system based on the model to find out the characteristics and identification of the bat species. The study showed that C5.0 algorithm prevailed and was selected with the mean score of accuracy of 98.98%, while the mean score of accuracy for the random forest was 97.26%. As many 50 rules were implemented in the DSS to identify common and rare bat species with morphometric and morphological attributes.
Volume: 15
Issue: 3
Page: 1215-1222
Publish at: 2017-09-01

Weighted Least Squared Approach to Fault Detection and Isolation for GPS Integrity Monitoring

10.12928/telkomnika.v15i3.5800
Ershen; Shenyang Aerospace University Wang , Fuxia; Shenyang Aerospace University Yang , Pingping; Shenyang Aerospace University Qu , Tao; Shenyang Aerospace University Pang , Xiaoyu; Shenyang Aerospace University Lan
Reliability of a global navigation satellite system is one of great importance for global navigation purposes. Therefore, an integrity monitoring system is an inseparable part of aviation navigation system. Failures or faults due to malfunctions in the systems should be detected to keep the integrity of the system intact. In order to solve the problem that least squares method detects and isolates a satellite fault for GPS integrity monitoring, in this paper, a weighted least squares algorithm is proposed for satellite fault detection and isolation. The algorithm adopts the diagonal elements of the covariance matrix of GPS measurement equation as the weighted factor. Firstly, the weighted least squares approach for satellite fault detection establishes the test statistic by the sum of the squares of the pseudo-range residuals of each satellite for GPS. Then, the detection threshold is obtained by the false alarm rate of the fault detection, probability density function and visiable satellite number.The effectiveness of the proposed approach is illustrated in a problem of GPS (Global Positioning System) autonomous integrity monitoring system. Through the real raw measured GPS data，based on least squares RAIM method and the weighted least squares RAIM approach, the performance of the two algorithms is compared. The results show that the proposed RAIM approach is superior to the least squares RAIM algorithm in the sensitivity of fault detection and fault isolation performance for GPS integrity monitoring.
Volume: 15
Issue: 3
Page: 1022-1030
Publish at: 2017-09-01

Agent Based Modeling on Dynamic Spreading Dengue Fever Epidemic

10.12928/telkomnika.v15i3.4511
Heti; Bogor Agricultural University Mulyani , Taufik; Bogor Agricultural University Djatna , Imas Sukaesih; Bogor Agricultural University Sitanggang
Agent based model (ABM) is a computational model for simulation, behavioral representation and interaction of autonomous agents. The main problem definition related to how to make a dynamic model of dengue fever with consideration of their behavioral and interaction agent. This paper aims to develop interactive behavioral agents and related simulation models for such dynamic spreading dengue fever epidemic. This model construction consists of two agents, namely a human agent as a host and mosquito as a vector, where temperature and humidity are the environmental parameters. These environmental parameters deployed data and information from National Meteorology Climatology and Geophysics agency and supported by recent community health data of Bogor region. The verification stage evaluated model performance of two periods between January to June and between July to December 2015 showed the fitness of the model. During simulation stage where 100 humans agent and 10 mosquitoes agent were observed, indicating the decreasing of mosquito by 26.3% and the number of infected human decrease to 16% from the period of January until June to July until December 2015 respectively. These evaluation results showed that the agent based model results succeeded to follow a similar trend of decreasing pattern as actual data.
Volume: 15
Issue: 3
Page: 1380-1388
Publish at: 2017-09-01

A Soft Set-based Co-occurrence for Clustering Web User Transactions

10.12928/telkomnika.v15i3.6382
Edi; Telkom University Sutoyo , Iwan Tri Riyadi; Universitas Ahmad Dahlan Yanto , Rd Rohmat; Telkom University Saedudin , Tutut; University of Malaya Herawan
Grouping web transactions into some clusters are essential to gain a better understanding the behavior of the users, which e-commerce companies widely use this grouping process. Therefore, clustering web transaction is important even though it is challenging data mining issue. The problems arise because there is uncertainty when forming clusters. Clustering web user transaction has used the rough set theory for managing uncertainty in the clustering process. However, it suffers from high computational complexity and low cluster purity. In this study, we propose a soft set-based co-occurrence for clustering web user transactions. Unlike rough set approach that uses similarity approach, the novelty of this approach uses a co-occurrence approach of soft set theory. We compare the proposed approach and rough set approaches regarding computational complexity and cluster purity. The result demonstrates better performance and is more effective so that lower computational complexity is achieved with the improvement more than 100% and cluster purity is higher as compared to two previous rough set-based approaches.
Volume: 15
Issue: 3
Page: 1344-1353
Publish at: 2017-09-01

94 GHz Millimeter Wave Conducted Speech Enhancement

10.12928/telkomnika.v15i3.5166
Sheng; Xijing University Li , Fuming; Fourth Military Medical University M. Chen , Jinyan; Xijing University Hu , Hongbo; Xijing University Li , Lijun; Xijing University Qiu , Ying; Xijing University Tian , Jianqi; Fourth Military Medical University Wang
This paper is under in-depth investigation due to suspicion of possible plagiarism on a high similarity indexThe traditional microphone speech acquisition method has several limitations, such as short acquisition distance, non-directivity, weak ability to compensate for anti-acoustic noise, and poor sensitivity. As an alternative, our lab developed a new type of speech detection system using bio-radar. This novel speech detection method may effectively compensate for the shortcomings of the traditional microphone because of the special features of bio-radar. However, the detected radar speech is also corrupted by specific electromagnetic and ambient noises. Therefore, this study proposes a minimum mean-square error (MMSE) short-time spectral amplitude estimate algorithm to enhance radar captured speech. Because the proposed approach employs an optimal spectral amplitude estimator as well as a method to minimize the mean-square error of the log-spectra in enhancing noisy speech, this algorithm significantly reduces the colored residual noise. The enhanced radar speech was evaluated by both subjective and objective quality evaluation methods. The results demonstrate that the bio-radar can successfully detect speech signal and the proposed speech enhancement algorithm can improve radar captured speech quality.
Volume: 15
Issue: 3
Page: 1072-1078
Publish at: 2017-09-01

Design and Improvement of a Compact Bandpass Filter using DGS Technique for WLAN and WiMAX Applications

10.12928/telkomnika.v15i3.6917
Ahmed; German research Foundation (DFG) Boutejdar , Mohamed; Université Sidi Mohamed ben Abdellah Amzi , Saad Dosse; Université Sidi Mohamed ben Abdellah Bennani
This paper is under in-depth investigation due to suspicion of possible plagiarism on a high similarity indexIn this article, A compact size band pass filter based on octagonal resonators is presented to give sharp response at desired frequency bands along with very low insertion loss. The proposed filter structure is composed of octagonal microstrip resonators, backed by Quasi-Yagi slots ‘Quasi-Yagi Defected Ground Structure’ (Quasi-Yagi-DGS). By controlling the electrical coupling between the octagonal–strip and the Quasi-Yagi-DGS, the bandpass filter’s stopband is optimized for better rejection. The proposed BPF has low insertion loss and compact size because of the slow-wave effect. Meanwhile, sharp rejection bands induced by the presence of two transmission zeros. The simulated center frequency and passband insertion loss are 2.4 GHz and 0.6 dB, respectively.
Volume: 15
Issue: 3
Page: 1137-1144
Publish at: 2017-09-01
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