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29,734 Article Results

Transient Power Quality Performance of Multi Photovoltaics using MPPT P and O/MPPT Fuzzy

10.12928/telkomnika.v16i6.9897
Amirullah; Institut Teknologi Sepuluh Nopember Amirullah , Agus; University of Bhayangkara Surabaya Kiswantono , Ontoseno; Institut Teknologi Sepuluh Nopember Surabaya Penangsang , Adi; Institut Teknologi Sepuluh Nopember Surabaya Soeprijanto
This paper presents comparative performance of transient power quality due to multi photovoltaic (PV) integration to grid at both fixed temperature and solar irradiation connected using Maximum Power Point Tracking Perturb and Observe (MPPT P and O)/MPPT Fuzzy. This research is performed as five transient of short-circuit faults on point common coupling (PCC) bus. An artificial intelligence with fuzzy logic controller (FLC) is used to set duty cycle with step variable to control DC/DC boost converter, generate quick convergence to determine MPPT for controlling of PV output voltage. Furthermore the result is compared with MPPT P and O. During transient phase, non-symmetrical faults are able to result an unbalance current/voltage greater than symmetrical faults. On symmetrical faults, MPPT Fuzzy is able to resultan average THD voltage/THD current smaller than MPPT P and O. Otherwise on non-symmetrical faults, MPPT P and O is able to resultan average THD voltage/THD current slightly smaller than MPPT Fuzzy. Both of MPPT P and O and MPPT Fuzzy on all short circuit faults during transient phase are able to result significantly smaller current average THD current than average THD voltage and limits of THD prescribed in IEEE 519. This research is simulated using Matlab/Simulink environment.
Volume: 16
Issue: 6
Page: 2967-2979
Publish at: 2018-12-01

Detection and Separation of Eeg Artifacts Using Wavelet Transform

10.11591/ijict.v7i3.pp149-156
R. Suresh Kumar , P. Manimegalai
Bio-medical signal processing is one of the most important techniques of multichannel sensor network and it has a substantial concentration in medical application. However, the real-time and recorded signals in multisensory instruments contains different and huge amount of noise, and great work has been completed in developing most favorable structures for estimating the signal source from the noisy signal in multichannel observations. Methods have been developed to obtain the optimal linear estimation of the output signal through the Wide-Sense-Stationary (WSS) process with the help of time-invariant filters. In this process, the input signal and the noise signal are assumed to achieve the linear output signal. During the process, the non-stationary signals arise in the bio-medical signal processing in addition to it there is no effective structure to deal with them. Wavelets transform has been proved to be the efficient tool for handling the non-stationary signals, but wavelet provide any possible way to approach multichannel signal processing. Based on the basic structure of linear estimation of non-stationary multichannel data and statistical models of spatial signal coherence acquire through the wavelet transform in multichannel estimation. The above methods can be used for Electroencephalography (EEG) signal denoising through the original signal and then implement the noise reduction technique to evaluate their performance such as SNR, MSE and computation time.
Volume: 7
Issue: 3
Page: 149-156
Publish at: 2018-12-01

An Intelligent Framework Prototype for Monitoring Students in Virtual Classroom

10.11591/ijeecs.v12.i3.pp1151-1158
Ashutosh Satapathy , Jenila Livingston L. M
Virtual classroom is one of the fastest growing educational technologies used by many industries and institutions. Today, Voice over Internet Protocol (VoIP) cloud is become a most accepted replacement to different virtual classroom technologies such as internet chat, internet radio, web conferencing, traditional video conferencing and peer to peer VoIP calls. It provides greater flexibility, reliability and cost efficient telecommunication features and operates on comparatively lesser bandwidth. Involvement of new technology in virtual classroom makes it more reliable to teachers and students. Still it follows traditional methods to monitor students by invigilator whether it may be inside the classroom or home study. A secure framework for virtual classroom is developed to not only monitor student’s activities continuously but also the amount of time spent by each student and provide security against unsecure unauthorized login. An effective monitoring System based on Liveness Face Detection techniques is proposed to add more flexibility to conduct virtual classroom and also increases the level of securities of each student’s accounts.
Volume: 12
Issue: 3
Page: 1151-1158
Publish at: 2018-12-01

Using Alpha-cuts and Constraint Exploration Approach on Quadratic Programming Problem

10.12928/telkomnika.v16i6.11584
Yosza; Universiti Teknikal Malaysia Melaka (UTeM) Dasril , Zahriladha; Universiti Teknikal Malaysia Melaka (UTeM) Zakaria , Ismail Bin; Universiti Putra Malaysia (UPM) Mohd
In this paper, we propose a computational procedure to find the optimal solution of quadratic programming problems by using fuzzyalpha-cuts and constraint exploration approach. We solve the problems in the original form without using any additional information such as Lagrange’s multiplier, slack, surplus and artificial variable. In order to find the optimal solution, we divide the calculation in two stages. In the first stage, we determine the unconstrained minimization of the quadratic programming problem (QPP) and check its feasibility. By unconstrained minimization we identify the violated constraints and focus our searching in these constraints. In the second stage, we explored the feasible region along side the violated constraintsuntil the optimal point is achieved. A numerical example is included in this paper to illustrate the capability of alpha-cuts and constraint exploration to find the optimal solution of QPP.
Volume: 16
Issue: 6
Page: 2782-2790
Publish at: 2018-12-01

Optimal Control for Torpedo Motion based on Fuzzy-PSO Advantage Technical

10.12928/telkomnika.v16i6.8979
Viet Dung; Ho Chi Minh City University Do , Xuan Kien; Ho Chi Minh City University Dang
The torpedo is a nonlinear object which is very difficult to control. Via to manage the rudder angle yaw, the diving plane angle, and the fin shake reduction, the torpedo yaw horizontal, the depth vertical and roll damping of the system are controlled accurately and steadily. In this paper, the particle swarm optimization is used to correct the imprecision of architecture fuzzy parameters. The coverage width of membership function and the overlap degree influence of neighboring membership functions are considered in the method to adjust dynamically from the system errors. Thereby optimizing the control signal and enhancing the torpedo motion quality. The proposed method results in a better performance compared to the other control method such as adaptive fuzzy-neural that proved effective of the proposed controller.
Volume: 16
Issue: 6
Page: 2999-3007
Publish at: 2018-12-01

A Comprehensive Review on Applications of Don’t Care Bit Filling Techniques for Test Power Reduction in Digital VLSI Systems

10.11591/ijeecs.v12.i3.pp941-949
Sanjoy Mitra , Debaprasad Das
Massive power consumption during VLSI testing is a serious threat to reliability concerns of ubiquitous silicon industry. A significant amount of low-power methodologies are proposed in the relevant literature to address this issue of test mode power consumption and don’t care bit(X) filling approaches are one of them in this fraternity. These don’t care(X) bit filling techniques have drawn the significant attention of industry and academia for its higher compatibility with existing design flow as neither modification of the CUT is required nor they need to rerun the time-consuming ATPG process. This paper presents an empirical survey of those X-bit filling techniques, applied to mitigate prime two types of dynamic power dissipation namely shift power and capture power, occurred during full scan testing.
Volume: 12
Issue: 3
Page: 941-949
Publish at: 2018-12-01

Modified SEPIC Converter Performance for Grid-connected PV Systems under Various Conditions

10.12928/telkomnika.v16i6.10148
Rizky Ajie; Universitas Negeri Semarang Aprilianto , Subiyanto; Universitas Negeri Semarang Subiyanto , Tole; Universitas Ahmad Dahlan Sutikno
Step-up converter is widely used to increase DC voltage level on PV systems either off-grid or grid connected. One of the step-up converters often used in PV systems is SEPIC converter. To improve its performance, many SEPIC converters have been modified. However, performance on various conditions has not been further investigated. In this study, the modified SEPIC converter was investigated under various change conditions for grid-connected PV applications. This converter was modelled and simulated using PSIM software. The modified SEPIC converter received input from PV array 15 kWp, and its output was connected to the three-phase inverter with grid and load. The irradiance level and ambient temperature were varied to test its performance and compared to Boost converter and SEPIC converter. For all tests, the performance of modified SEPIC converter was better than other step-up converters because it was able to rectify the quality of output voltage and more efficient.
Volume: 16
Issue: 6
Page: 2943-2953
Publish at: 2018-12-01

Item Analysis for the Adapted Motivation Scale Using Rasch Model

10.11591/ijere.v7i4.15376
Sar Ee Ng , Kee Jiar Yeo , Azlina bt Mohd Kosnin
The aim of this study was to measure the validity and reliability of an adapted motivation scale used in second language learning.  The Integrative and Instrumental motivation (IIM)  was developed based on two orientations of motivation, which were integrative motivation and instrumental motivation.  IIM was used to identify students’ level of motivation towards learning Chinese language as a second language (CLSL) in national school.  The study presented empirical evidence of validity and reliability using the Rasch Model.   Pilot study was conducted in a national school which has students enrolled for the CLSL class.   There were 29 students in this pilot study.  Data was  analyzed using WINSTEPS version 3.72.3.  The result showed the reliability of the motivation scale is 0.87 based on Cronbach’s alpha.  The construct validity was determined by PT-measure correlation value (PMC) range from 0.71 to 0.86, infit and outfit MNSQ  between 0.53 to 1.43 and ZSTD range from -1.1 to 1.2. In unidimensional measure, raw variance explained was at 66.4%  with the unexplanined variance in the first factor was at 13.6%.  Finally the fit statistics showed that person separation index, 2.79 was considered good and item separation index, 1.81was in acceptable range (Linacre,2012).  Person and item reliability were at 0.89 and 0.77 respectively.  The result indicated that the new instrument with 15 items-IIM after eliminated unfit items was a reliable and valid instrument to measure the motivation in learning CLSL in the context of national school.
Volume: 7
Issue: 4
Page: 264-269
Publish at: 2018-12-01

Radial Derivative and Radial Inversion for Interpreting 4D Gravity Anomaly Due to Fluids Injection Around Reservoir

10.12928/telkomnika.v16i6.9468
Muhammad; Universitas Gadjah Mada Zuhdi , Sismanto; Universitas Gadjah Mada Sismanto , Ari; Universitas Gadjah Mada Setiawan , Jarot; Universitas Gadjah Mada Setyowiyoto , Adi; Universitas Brawijaya Susilo , Muhammad; Universitas Lampung Sarkowi
The 4D gravity or time lapse gravity has been used many reseracher to identify fluid injection in oil reservoir. The objective of this study is to find the better way in interpreting 4D gravity anomaly due to fluid injection around the reservoir. Radial Derivatives are derivative values of gravity anomalies against horizontal distances in the radial direction. Radial inversion is a two-dimensional inversion of lines with radial directions resulting in a 3-dimension model. Time lapse microgravity research have been performed in “X Oil Field” with amount of 604 data point covering area of 4000m x 5000m. This Radial derivative and Radial inversion have been aplied at an injection well of the X oil field. The yield show that 4D gravity anomaly value due to injection is 0.02 mGal to 0.36 mGal. Radial derivative value in the area is 0 micro Gal/cm to 0,012 mGal/meter. Radial inversion shows radius of fluid front movement is 304 meters to 1120 meters. Radial derivative and Radial inversion have been proven fairly good to identify injected fluid movement in the reservoir.
Volume: 16
Issue: 6
Page: 2855-2863
Publish at: 2018-12-01

Design of Tunable Multiband Hybrid Graphene Metal Antenna in Microwave Regime

10.11591/ijeecs.v12.i3.pp1003-1009
Hussein A. Abdulnabi , Yasin Yousif Al-Aboosi
Graphene is an allotrope (form) of carbon consisting of a single layer of carbon atoms arranged in an hexagonal lattice. It is the basic structural element of many other allotropes of carbon, such as graphite, charcoal, carbon nanotubes and fullerenes. In this paper, a tunable hybrid metal-graphene antenna in the microwave regime is proposed. This antenna composed of the copper patch and four graphene strips. The antenna designs used for the cellular long-term evolution system and the operating frequency bands of 1.8, 2.5, 2.6, and 3.6 GHz, are evaluated to demonstrate the working principle and the performance tradeoffs. Furthermore, the proposed antenna can be tuned by varying applied DC voltage on the graphene which leads to change in the chemical potential of the graphene and hence the surface conductivity and electrical properties are changed. The simulation results reveal that the antenna operates in multi-band where scattering factor S11< -10 dB. In addition, the results show that hybrid metal-graphene frequency reconfigurable antennas can, at the same time, provide a tunable bandwidth and antenna matching.
Volume: 12
Issue: 3
Page: 1003-1009
Publish at: 2018-12-01

Design Mobile App for Increase the Visitor Museum using Gamification Method

10.12928/telkomnika.v16i6.10384
Novian Adi; Universitas Atma Jaya Yogyakarta Prasetyo , Suyoto; Universitas Atma Jaya Yogyakarta Suyoto
The museum's tourism object currently has a low visitor level compared to other tourism objects, even though the museum's function is very important as an enhancer of people's cultural knowledge. Judging from the small level of visitors, it cannot be separated from the effects of the promotion carried out by the museum. From the surveys that have been conducted, museum promotion uses social media more directly to the public, banners, radio, television, blogs and internet social media. In this study, an application that serves to promote museums using gamification methods was designed, this method was chosen because of the many existing promotional techniques, there is still little promotion using game content, therefore the gamification method is expected to encourage the motivation of users to visit the museum. This application will provide convenience to the museum management to promote the museum with media game content without having to spend large development and maintenance costs.
Volume: 16
Issue: 6
Page: 2791-2798
Publish at: 2018-12-01

Analysis Predicted Location of Harmonic Distortion in RF Upconverter Structure

10.12928/telkomnika.v16i6.7628
Sirmayanti; The State Polytechnic of Ujung Pandang Sirmayanti , Mike; Victoria University Faulkner
A new mathematical analysis to predict the magnitude size of the distortion products from the signal up-conversion process output is presented. The signal up-conversion process converts the digital baseband from the analog baseband into a radio frequency signal. When the signal baseband involves frequency offsetting then occurring a number of distortion products which can reduce the dynamic range so it is difficult to meet the spectrum mask requirements within the operating band. This paper will focus on methods of new mathematical analysis using a continuous frequency range and only applies to a single side band tone, with constant amplitude into any value of frequency offsets. The novel contribution to the analysis starts at generating the gate signal and convolution of the gate signal into the reference carrier signal. The results show very close between the simulation results and the calculation of the predicted location of the distortions.
Volume: 16
Issue: 6
Page: 2608-2615
Publish at: 2018-12-01

Electromagnetic Characteristics Measurement of Organic Material Absorber

10.12928/telkomnika.v16i6.9687
Reza; Centre of Electronics Technology Septiawan , Sardjono; Centre of Electronics Technology Trihatmo , Juliati; Centre of Electronics Technology Junde , Dody A.; Center of Polymer Technology Winarto , Arief; Centre of Electronics Technology Rufiyanto , Erik Madyo; Centre of Electronics Technology Putro , Budi; Centre of Electronics Technology Sulistya , Arky; Centre of Electronics Technology Astasari
Electro Magnetic Compatibility (EMC) Chamber requires high performance absorber material to assure the quality of EMC chamber related to Radio Frequency (RF) shielding effectiveness of the corresponding chamber. RF shielding effectiveness is measured following EN 50147-1 testing method. EMC laboratory of BPPT (Indonesian Agency for the Assessment and Application of Technology uses polyurethane absorber material which absorbs the carbon-neoprene mixture to maintain consistent RF performance over a broad frequency band, especially in the frequency range of CISPR 22 radiated emission test between 30 MHz to 6 GHz, limits in CISPR 22 (Information technology equipment-radio disturbance characteristics-limits and methods of measurement). This paper proposes alternative absorber materials based on organic materials: rice husk, coconut husk, cotton and sawn wood crumbs. In the early phase of this research, the frequency under consideration are 900 MHz and 1800 MHz. These frequencies are mostly used by mobile phone devices, therefore at this phase the resulted organic material absorber may be used for alternative mobile phone casing before to be used as absorber material for EMC laboratory in a broader frequency band. The organic materials are produced by mixing them with cement, carbon, and resin. Free space testing method is used in the measurements. Results has shown a mixture of 50% coconut husk with resin absorb the most radiated emission in 900 MHz, while 30% of coconut husk will absorb the most radiated emission in 1800 MHz.
Volume: 16
Issue: 6
Page: 2507-2513
Publish at: 2018-12-01

An Opportunity for Values Education in Higher Education: Social Responsibility and Healthy Living Course

10.11591/ijere.v7i4.14768
Gökhan Izgar
The purpose of this study is to determine the contribution of the “social responsibility and healthy living” course, which was put into effect at a state university for the first time in Turkey, within the scope of elective courses on students’ acquisition of values. The data in this study, in which action research, one of the qualitative research designs, was conducted, were obtained using the semi-structured interview form prepared by the researcher. The data obtained were analyzed using the descriptive analysis and content analysis techniques, which are qualitative data analysis methods. 39 students participated in the study on a voluntary basis. As a result of the analysis of the data, it was concluded that the action plan developed within the scope of the social responsibility and healthy living course was effective in the acquisition of values of taking responsibility, charitableness, being useful, ethics, empathy, importance of the institution of family, cooperation-solidarity, patience, gratitude (thankfulness), freedom of thought and respect for differences. Likewise, some of the students stated that this course contributed to their views and behaviors concerning healthy living. However, a considerable number of students were of the opinion that either the course did not make a contribution or made a partial contribution. In addition, the students pointed out that the way the course was taught was fruitful and practice-based,, that it was fun and informative and that the projects and readings contributed to learning. Yet, there were also negative student views about the course content and the method of teaching employed. Moreover, it was important that a theme emerged indicating that class hours were not sufficient.
Volume: 7
Issue: 4
Page: 331-340
Publish at: 2018-12-01

An Adaptive Internal Model for Load Frequency Control Using Extreme Learning Machine

10.12928/telkomnika.v16i6.11553
Adelhard Beni; Hiroshima University Rehiara , He; Hiroshima University Chongkai , Yutaka; Hiroshima University Sasaki , Naoto; Hiroshima University Yorino , Yoshifumi; Hiroshima University Zoka
As an important part of a power system, a load frequency control has to be prepared with a better controller to ensure internal frequency stability. In this paper, an Internal Model Control (IMC) scheme for a Load Frequency Control (LFC) with an adaptive internal model is proposed. The effectiveness of the IMC control has been tested in a three area power system. Results of the simulation show that the proposed IMC with Extreme Learning Machine (ELM) based adaptive model can accurately cover the power system dynamics. Furthermore, the proposed controller can effectively reduce the frequency and mechanical power deviation under disturbances of the power system.
Volume: 16
Issue: 6
Page: 2879-2887
Publish at: 2018-12-01
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