Articles

Access the latest knowledge in applied science, electrical engineering, computer science and information technology, education, and health.

Advanced Search
Filter Icon

Filters article

Years

FAQ Arrow
Single Year
Range Year
0
0

Source Title

FAQ Arrow

Authors

FAQ Arrow

28,296 Article Results

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

A Proposed Design of Unit Cell of Metamaterial for 5G Mobile Communication

10.12928/telkomnika.v15i3.6079
Jamal Mohammed; University of Technology, Baghdad Rasool
This paper is under in-depth investigation due to suspicion of possible plagiarism on a high similarity indexIn this manuscript a design of metamaterial unit cells which are new artificial materials made of periodic arrangement much smaller than the guided wavelength, are proposed which are suitable to work for 5G mobile communication working with millimeter frequency band at 28 GHz due the high demand for the frequency spectrum for mobile networks .The structures of unit cells were simulated using High Frequency Structure Simulator HFSS software. The design starts with the metamaterial structure which is composed of double rectangular (DRR) and circular split ring resonator (DSRR). The results of simulation showed very good results such as wide operating frequency band which is 1.34 GHz with very law radiation losses the unit cell designed to overrun the radiation losses which are appear with the work of metamaterials.
Volume: 15
Issue: 3
Page: 1145-1148
Publish at: 2017-09-01

Social Media Success Model for Knowledge Sharing (Scale Development and Validation)

10.12928/telkomnika.v15i3.5569
Setiawan; STIKOM Dinamika Bangsa Assegaff , Hendri; STIKOM Dinamika Bangsa Hendri , Akwan; STIKOM Dinamika Bangsa Sunoto , Herti; STIKOM Dinamika Bangsa Yani , Desy; STIKOM Dinamika Bangsa Kisbiyanti
This study aimed to evaluate the success of social media as a means of sharing knowledge among scholars in Indonesia. By using Information System Success Model (DeLone and McLean), this study develops a research model that will be used to investigate what factors are contributing to the success of social media as tool for sharing knowledge among academics. This article would focus on the discussion of instrument development and validation process. The method for development and validation the research instrument was refers to the framework proposed by McKanzie et al. This study resulted in a validated instrument, the instrument could use by researchers who are interested in study social media success for knowledge sharing.
Volume: 15
Issue: 3
Page: 1335-1343
Publish at: 2017-09-01

Application Profiling and Mapping on NoC-based MPSoC Emulation Platform on Reconfigurable Logic

10.12928/telkomnika.v15i3.6513
Jia Wei; Universiti Teknologi Malaysia Tang , Yuan; Universiti Teknologi Malaysia Wen Hau , Nasir; Universiti Teknologi Malaysia Shaikh-Husin , Muhammad Nadzir; Universiti Teknologi Malaysia Marsono
In network-on-chip (NoC) based multi-processor system-on-chip (MPSoC) development, application profiling is one of the most crucial step during design time to search and explore optimal mapping. Conventional mapping exploration methodologies analyse application-specific graphs by estimating its runtime behaviour using analytical or simulation models. However, the former does not replicate the actual application run-time performance while the latter requires significant amount of time for exploration. To mapapplications on a specific MPSoC platform, the application behaviour on cycle-accurate emulated platform should be considered for obtaining better mapping quality. This paper proposes an application mapping methodology that utilizes a MPSoC prototyped in Field-Programmable Gate Array (FPGA). Applications are implemented on homogeneous MPSoC cores and their costs are analysed and profiled on the platform in term of execution time, intra-core communication and inter-core communication delays. These metricsare utilized in analytical evaluation of the application mapping. The proposed analytical-based mapping is demonstrated against the exhaustive brute force method. Results show that the proposed method is able to produce quality mappings compared to the ground truth solutions but in shorter evaluation time.
Volume: 15
Issue: 3
Page: 1040-1047
Publish at: 2017-09-01

Synchronization Control of Complex Dynamical Networks Based on Uncertain Coupling

10.12928/telkomnika.v15i3.4224
Qianqian; Tianjin University of Technology Jia
This paper is under in-depth investigation due to suspicion of possible plagiarism on a high similarity indexIn recent years, the study of complex networks has been a focus subject of technology fields. In this paper, we consider the adaptive control and synchronization of uncertain complex networks. By using the adaptive control techniques with the linear feedback updated law and the well-known LaSalle invariant principle on dynamical system theory, some simple yet generic criteria are derived. Furthermore, the result is applied to typical chaotic cellular neural networks (CNN). Finally, numerical simulations are presented to demonstrate the feasibility and effectiveness of the proposed techniques.
Volume: 15
Issue: 3
Page: 1164-1172
Publish at: 2017-09-01

A Three-Phase Grid-Connected PV System Based on SAPF for Power Quality Improvement

10.12928/telkomnika.v15i3.5439
Rachid; Badji Mokhtar University Belaidi , Ali; Badji Mokhtar University Haddouche , Djamila; UDES, EPST/ CDER Ghribi , M.; UDES, EPST/ CDER Mghezzi Larafi
This paper proposes a combined system of three-phase four-wire shunt active power filter (SAPF), and photovoltaic generator (PVG), to solve the power quality problems such as harmonic currents, poor power factor, and unbalanced load. In addition, the proposed system can inject the issued energy from the PVG into the utility grid. To increase the efficiency of the PVG and extract the maximum photovoltaic (PV) power under variable atmospheric conditions, a maximum power point tracking (MPPT) technique based on perturb and observe (P&O) is implemented in the DC/DC boost converter. The effectiveness of the proposed PVG-SAPF (PVG and SAPF) based on the use of synchronous reference frame theory (SRF theory) under unbalanced nonlinear load. The proposed PVG-SAPF is validated through numerical simulations using Matlab/Simulink software. The simulation results show the effectiveness of the proposed PVG-SAPF. 
Volume: 15
Issue: 3
Page: 1003-1011
Publish at: 2017-09-01

Flexible Wearable Antenna on Electromagnetic Band Gap using PDMS substrate

10.12928/telkomnika.v15i3.7214
Adel; Universiti Tun Hussein Onn Malaysia (UTHM) Y. I. Ashap , Z.; Universiti Tun Hussein Onn Malaysia (UTHM) Z. Abidin , S.; Universiti Tun Hussein Onn Malaysia (UTHM) H. Dahlan , H.; Universiti Tun Hussein Onn Malaysia (UTHM) A. Majid , S.; Universiti Tun Hussein Onn Malaysia (UTHM) K. Yee , Gameel; University of Dammam, Dammam 1982 Saleh , Norun; International Islamic University Malaysia (IIUM) Abdul Malek
A robust and low-profile electromagnetic band-gap (EBG) based on flexible wearable antenna covering 2.4 GHz frequency band is presented. The incorporated EBG with antenna reduces the  radiation into the human body around 17 dB and decreases the impacts of frequency detuning. The overall dimension of the antenna integrated with EBG is 56 x 56 x 4 mm3 with relative impedance bandwidth of 8.3% is achieved. The proposed design has improved the gain up to 7 dBi. Specific absorption rate (SAR) assessment is also studied to certify the performance of the antenna when it is located proximity to human tissue. The flexible antenna with aforementioned performances could be chosen as a good candidate for integration into a range of wearable devices for medical application.
Volume: 15
Issue: 3
Page: 1454-1460
Publish at: 2017-09-01

Performance Evaluation of Multicarrier Based Techniques for Single Phase Hybrid Multilevel Inverter using Reduced Switches

10.11591/ijeecs.v7.i3.pp676-686
Nunsavath Susheela , P. Satish Kumar
The multilevel inverters are very popular in high power high voltage applications. However the multilevel inverters has some demerits such as requiring higher number of components, PWM control method is complex and capacitor voltage balancing problem. The hybrid multilevel inverter presented in this paper has superior characteristics over conventional multilevel inverters. The hybrid multilevel inverter employs fewer components and less carrier signals when compared to conventional multilevel inverters. It consists of level generation and polarity generation stages which involves high frequency and low frequency switches. The complexity and overall cost for higher output voltage levels are greatly reduced. Implementation of single phase 7-level, 9-level and 11-level hybrid multilevel inverter has been performed using sinusoidal pulse width modulation (SPWM) strategies i.e., phase disposition (PD), alternate phase opposition disposition (APOD) and carrier overlapping (CO). Also the three techniques are compared in terms of total harmonic distortion (THD) for various modulation indices and observed to be greatly improved when compared to conventional topologies. The performance of single phase eleven level hybrid inverter is analyzed for different loads.  Simulation is performed using MATLAB/ Simulink.
Volume: 7
Issue: 3
Page: 676-686
Publish at: 2017-09-01

Discrete-time Inversion Model Control of a Double-damper System with Uncertain Parameters

10.11591/ijra.v6i3.pp168-177
Marwa Hannachi , Ikbel Bencheikh Ahmed , Dhaou Soudani
This paper addresses the control at discrete time of physical complex systems multi-inputs multi-outputs with variables parameters. Classified among the robust control laws the Internal Model Control (IMC) is adopted in this work to ensure the desired performances adjacent to the complexities of the system. However, the application of this control strategy requires that these different building blocks be open loop stable, which invites us, on the one hand, to apply the algebraic approach of Kharitinov for delimiting the summits stability domain’s system. On the other case, the Linear Matrix Inequalities (LMI) approach is applied to determine the corrector’s stability conditions obtained by a specific inversion of the chosen model. It is in this sense that we contribute by this work to execute the command by inversion the discrete-time model in order to ensure the stability and to maintain the performances the stability conditions of required for the double damper system with variable parameters.
Volume: 6
Issue: 3
Page: 168-177
Publish at: 2017-09-01

Development of Ammonia Gas Leak Detection and Location Method

10.12928/telkomnika.v15i3.5079
Ding; Harbin University of Science and Technology Xibo , Wang; Harbin University of Science and Technology Ru-yue
This paper proposed the gas for industrial ammonia leak diffusion model and the Gauss method of leakage localization. A set of wireless ammonia leak alarm system is composed of sensor node, network coordinator and host used in the industrial field was developed, the purpose is to reduce the loss of property caused by the leakage of ammonia industry. Using the monitoring system to carry out the ammonia leak location simulation measurement experiment, the result shows that the relative positioning error of the monitoring system is about 12%, which meets the needs of industrial production safety monitoring. Using the wireless sensor network to monitor the concentration of ammonia gas and locate the leakage source, it solves the problems of traditional wired alarm system, such as difficult wiring and weak expansibility, which helps to find the leak timely and provides a reference for the emergency rescue work.
Volume: 15
Issue: 3
Page: 1207-1214
Publish at: 2017-09-01

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
1 2 3
...
1886 1887
Show 1424 of 1887

Discover Our Library

Embark on a journey through our expansive collection of articles and let curiosity lead your path to innovation.

Explore Now
Library 3D Ilustration