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29,905 Article Results

A new technique to reduce overshoot in pneumatic positioning system

10.12928/telkomnika.v17i5.12807
Siti Fatimah; Universiti Teknikal Malaysia Melaka Sulaiman , M. F.; Universiti Teknologi Malaysia Rahmat , A. A. M.; Universiti Teknologi Malaysia Faudzi , Khairuddin; Universiti Teknikal Malaysia Melaka Osman
This paper presents a new approach for improving the performance of the pneumatic positioning system by incorporating a nonlinear gain function with observer system. System identification technique has been employed to represent the pneumatic system, while a model predictive control (MPC) with the observer system has been employed as the main controller to control the positioning of the system. The nonlinear gain function has been incorporated with the control strategy to compensate nonlinearities and uncertainties inherent in the parameters of the system. Unconstrained and constrained cases of control signals have been considered in this study. Simulation based on Matlab/Simulink indicated a reduction in overshoot of the system response for both cases due to additional nonlinear gain function in the strategy. Furthermore, remarkable enhancement was observed in effectiveness of this function while incorporated in constrained case, when this new strategy successfully improved the transient response in the pneumatic positioning system.
Volume: 17
Issue: 5
Page: 2607-2616
Publish at: 2019-10-01

Improving luminous flux and color homogeneity of dual-layer phosphor sctructure

10.12928/telkomnika.v17i5.11038
Tran Thanh; Ton Duc Thang University Trang , Phan Xuan; National Key Labrolatory of Digital Control and System Engineering Le , Nguyen Doan; Ton Duc Thang University Quoc Anh
In order to clarify the main purpose of the study, we put a green phosphor layer SrBaSiO4:Eu2+ on the yellow phosphorus layer YAG:Ce3+ through using only one WLEDs structure in different color temperatures like 5600 K, 6600 K, 7700K. Then, we find the suitable SrBaSiO4:Eu2+ concentration in order that the luminous flux could get the highest value. The results show that SrBaSiO4:Eu2+ brings great benefits to increase not only optical gain but also color uniformity. Specifically, the greater the SrBaSiO4:Eu2+ concentration, the greater the output of WLEDs because of the development of green light component in WLEDs. However, only if the SrBaSiO4:Eu2+ concentration exceeds the level, a slight decrease in color rendering index (CRI) can occur, which based on Monte Carlo simulation. In addition, the results of this paper have contributed significantly to the creation of higher-powered WLEDs.
Volume: 17
Issue: 5
Page: 2643-2649
Publish at: 2019-10-01

Breakdown on LDPE film due to partial discharge in air gap and its correlation with electrical properties and surface degradation

10.12928/telkomnika.v17i5.12245
Eka Putra; Andalas University Waldi , Yoshinobu; Toyohashi University of Technology Tempaku Murakami , Masayuki; Toyohashi University of Technology Tempaku Nagao
This paper describes the breakdown characteristic of the low density poly ethylene film caused by partial discharge in the air gap. The purpose of this paper is to clarify the effect number of discharge under repetition rectangular pulses with a needle-plane electrode system as a function of pulse frequency. The result performed, from 10 Hz up to 1000 Hz. From 10 Hz to 200 Hz, the pulse number up to breakdown did not change significantly with increasing the pulse frequency and the magnitude of partial discharge function of pulse number with varied frequency until breakdown were similar. By using both potential decay and surface degradation analysis function of number of pulse, the breakdown phenomena caused by partial discharge was shown to reveal a significant correlation between electrical properties and the transparency of its surface to change deposited on it by a partial discharge exposure.
Volume: 17
Issue: 5
Page: 2285-2291
Publish at: 2019-10-01

Gamification concept for encouraging lecture attendance

10.11591/ijeecs.v16.i1.pp482-490
Vinothini Kasinathan , Aida Mustapha , Chan Kok Fu , Mohamad Firdaus Che Abdul Rani , Sadesh Manikam
New generation of students has high dependence on technology and embrace social learning environments that have low barrier to access. This means in-class lectures are not popular anymore, and in fact has become a burden for them to cope. To resolve the issue of low student attendance, this paper proposes a character growth game with the concept of gamification in education that is able to track and reward student attendance called PetAttendToClass. PetAttendToClass is a client-based system developed using C# and unity3D game engine. Although finding from the UAT session revealed that some users believed that attendance is the responsibility of the student, gamification is meant to turn this mundane responsibility into something motivative, interactive and interesting. It is hoped that by gamifying the class attendance, student will be motivated to attend their daily classes.
Volume: 16
Issue: 1
Page: 482-490
Publish at: 2019-10-01

Performance comparison of PEMFC hydrogen reformer with different controllers

10.12928/telkomnika.v17i5.12817
Nor Aira; Universiti Tun Hussein Onn Malaysia Zambri , Norhafiz Bin; Universiti Teknikal Malaysia Melaka Salim , Faridah Hanim; Universiti Tun Hussein Onn Malaysia Mohd Noh , Sim Sy; Universiti Tun Hussein Onn Malaysia Yi
The renewable energy technology has become very popular due to major constraint in the existing electrical system such as high electricity demand, increased in fuel prices and concern of environmental pollution. The aims of this project are to develop a complete Proton Exchange Membrane Fuel Cell (PEMFC) model with hydrogen reformer by using MATLAB/ Simulink with three different controllers and comparison between the three controllers will be discussed. This project presents the development of methods to solve the problem of PEMFC output voltage by using different controllers which are Proportional Integral (PI), Proportional Integral Derivatives (PID) and Proportional Integral Fuzzy (PI-Fuzzy) controllers. The Ziegler Nicholas tuning method is used to tune PI and PID gains in a Simulink model. It helps the system to achieve a balance between performance and robustness for both controllers. The Mamdani type was used to develop the fuzzy controller in Simulink model. The transient performances that will be discussed are rise time, settling time, maximum overshoot, and percentage of overshoot. The results show that the proposed PI-Fuzzy is better than the conventionally used PI and PID controllers.
Volume: 17
Issue: 5
Page: 2617-2624
Publish at: 2019-10-01

Blind multi-signature scheme based on factoring and discrete logarithm problem

10.12928/telkomnika.v17i5.10525
Duc Nguyen; Posts and Telecommunication Institute of Technology Tan , Hai Nguyen; Academy of Cryptography Techniques Nam , Minh Nguyen; Academy of Cryptography Techniques Hieu
One of the important objectives of information security systems is providing authentication of the electronic documents and messages. In that, blind signature schemes are an important solution to protect the privacy of users in security electronic transactions by highlighting the anonymity of participating parties. Many studies have focused on blind signature schemes, however, most of the studied schemes are based on single computationally difficult problem. Also digital signature schemes from two difficult problems were proposed but the fact is that only finding solution to single hard problem then these digital signature schemes are breakable. In this paper, we propose a new signature schemes base on the combination of the RSA and Schnorr signature schemes which are based on two hard problems: IFP and DLP. Then expanding to propose a single blind signature scheme, a blind multi-signature scheme, which are based on new baseline schemes.
Volume: 17
Issue: 5
Page: 2327-2334
Publish at: 2019-10-01

Predictive torque control of electric vehicle

10.11591/ijece.v9i5.pp3522-3530
Mohammed El Amin Abdelkoui , Abdeldjebar Hazzab
The following article represents the development of a traction system of an electrical vehicle (EV) that consist of two Three-phase squirel-cage induction motors (IM) that permit the drive of the two front driving wheels. The two motors are controlled  using the Predictive Torque Control (PTC) method; A technique based on the next step prediction and evaluation of the electromagnetic torque and stator flux In a cost function in order to determinate the inverter switching vector that minimize the error between references and predicted values. PTC is what we tried to underline in this paper, so we explain below the principle of the method; and the system mathematical description is provided. An electronic differential is applied on the system to control independently the speed of the two wheels at different operating conditions in order to characterize the driving wheel system behavior, the robustness in steady state and in transient state.
Volume: 9
Issue: 5
Page: 3522-3530
Publish at: 2019-10-01

Enhancement of boresight radiation for leaky wave antenna array

10.12928/telkomnika.v17i5.12631
Mowafak K.; Universiti Teknikal Malaysia Melaka (UTeM) Mohsen , M. S. M; Universiti Teknikal Malaysia Melaka (UTeM) Isa , A. A. M.; Universiti Teknikal Malaysia Melaka (UTeM) Isa , M. K.; Universiti Teknikal Malaysia Melaka (UTeM) Abdulhameed , Mothana L.; Universiti Teknikal Malaysia Melaka (UTeM) Attiah , Ahmed M.; Universiti Teknikal Malaysia Melaka (UTeM) Dinar
An array of half-width microstrip leaky-wave antennas (HW-MLWAs) of two uniform elements was designed to obtain maximum boresight radiation. Achieve this, two uniform of HW-MLWAs are placed at 180◦ and fed by a probe located at the center between the elements, two uniforms of HW-MLWAs, loaded terminated by 50Ω lumped element. Two beams from two branches individual merge to form the resultant directive beam. The simulation represents the susceptibility of the proposed array of uniform HW-MLWAs to the radiation broadside direction effectively. The predict bandwidth matched of the array is 582 MHz (4.18–4.76 GHz). The direction of its main beam in boresight happens over a wide 13%, relatively (4.18-4.76 GHz) band. The proposed peak gain at the boresight direction of the array is 9.91 dBi.
Volume: 17
Issue: 5
Page: 2179-2185
Publish at: 2019-10-01

Evolving spiking neural networks methods for classification problem: a case study in flood events risk assessment

10.11591/ijeecs.v16.i1.pp222-229
Mohd Hafizul Afifi Abdullah , Muhaini Othman , Shahreen Kasim , Siti Aisyah Mohamed
Analysing environmental events such as predicting the risk of flood is considered as a challenging task due to the dynamic behaviour of the data. One way to correctly predict the risk of such events is by gathering as much of related historical data and analyse the correlation between the features which contribute to the event occurrences. Inspired by the brain working mechanism, the spiking neural networks have proven the capability of revealing a significant association between different variables spike behaviour during an event. Personalised modelling, on the other hand, allows a personal model to be created for a specific data model and experiment. Therefore, a personalised modelling method incorporating spiking neural network is used to create a personalised model for assessing a real-world flood case study in Kuala Krai, Kelantan based on historical data of 2012-2016 provided by Malaysian Meteorological Department. The result shows that the method produces the highest accuracy among the selected compared algorithms.
Volume: 16
Issue: 1
Page: 222-229
Publish at: 2019-10-01

Power consumption analysis on an IoT network based on wemos: a case study

10.12928/telkomnika.v17i5.11317
V.; MEASUREMENTS-Lab, Department of Physics, International Hellenic University Kanakaris , G. A.; HUMAIN-Lab, Computer of Science Department, International Hellenic University Papakostas , D. V.; MEASUREMENTS-Lab, Department of Physics, International Hellenic University Bandekas
On Internet of Things network (IoT), connections established among every device that connected to the Internet. An IoT uses different communication method instead to that, the Internet uses. Internet of Things (IoT) applications, use a light weight protocol Message Queue Telemetry Transport (MQTT). In this article an Internet of Things (IoT) system is presented, an advanced solution of monitoring the temperature and luminosity at different locations in a data centre of MQTT Server, measuring power consumption in 2 types of time of capturing data (every 0,5 min and every 1 min) making temperature and luminosity data visible over internet through cloud based dashboard. The quality of service (QoS) in some application is very crucial because the data collection is essential. This research focus on QoS in terms of power consumption as well as the battery life of the system. The results show that the battery life span is proportional to the QoS and the longevity of the battery and respectively the IoT network life depends on it.
Volume: 17
Issue: 5
Page: 2505-2511
Publish at: 2019-10-01

Humidity effect on electrical properties of graphene oxide back-to-back Schottky diode

10.12928/telkomnika.v17i5.12800
Shaharin Fadzli; Universiti Teknologi Malaysia Abd Rahman , Nurul Anati; Universiti Teknologi Malaysia Salleh , Mastura Shafinaz Zainal; Universiti Teknologi Malaysia Abidin , Amirjan; Universiti Teknologi Malaysia Nawabjan
A Schottky diode-based sensor is a promising structure for high sensitive and low power sensor. This paper investigates a device called back-to-back Schottky diode (BBSD) for humidity sensing operation. The BBSD provides simpler device configuration that can be fabricated using less complicated process. The current-voltage characteristic of the fabricated BBSD was measured at different relative humidity. From the obtained characteristics, series resistance, barrier height and ideality factor was analyzed. The device current increased at higher humidity level. The current increase could be associated to the decrease in series resistance, barrier height and ideality factor. When humidity decreased from 11 % to 97%, the barrier height showed reduction of 0.1 eV. The barrier height reduction was explained by considering electric field-induced reduction of graphene oxide. The observed result confirmed the device feasibility as promising simple and low cost humidity sensor.
Volume: 17
Issue: 5
Page: 2427-2433
Publish at: 2019-10-01

The design of virtual lower limb rehabilitation for post-stroke patients

10.11591/ijeecs.v16.i1.pp544-552
Lee Wei Jian , Syadiah Nor Wan Shamsuddin
Stroke is one of the leading causes that elicits to disability for adults over a long period. Post-stroke patients often have difficulties with joints and muscles in their legs, which prevents them from moving around. Lower limb rehabilitation helps to regain normal mobility and functionality of patients such as standing, walking and climbing stairs. The implementation of virtual reality in stroke rehabilitation helps to encourage patients on frequent engagement with exercise. This paper briefly presents the ongoing research regarding lower limb rehabilitation systems for post-stroke patient in virtual reality environment to provide an overview of the conceptual design, limitations, and suggestions for future work in this direction.
Volume: 16
Issue: 1
Page: 544-552
Publish at: 2019-10-01

Half-duplex power beacon-assisted energy harvesting relaying networks: system performance analysis

10.11591/ijece.v9i5.pp3399-3406
Tan N. Nguyen , Minh Tran , Van-Duc Phan , Hoang-Nam Nguyen , Thanh-Long Nguyen
In this work, the half-duplex (HF) power beacon-assisted (PB) energy harvesting (EH) relaying network, which consists of a source (S), Relay (R), destination (D) and a power beacon (PB) are introduced and investigated. Firstly, the analytical expressions of the system performance in term of outage probability (OP) and the system throughput (ST) are analyzed and derived in both amplify-and-forward (AF) and decode-and-forward (DF) modes. After that, we verify the correctness of the analytical analysis by using Monte-Carlo simulation in connection with the primary system parameters. From the numerical results, we can see that all the analytical and the simulation results are matched well with each other.
Volume: 9
Issue: 5
Page: 3399-3406
Publish at: 2019-10-01

A review on sensing-based strategies of interior lighting control system and their performance in commercial buildings

10.11591/ijeecs.v16.i1.pp208-215
Khairul Rijal Wagiman , Mohd Noor Abdullah , Mohammad Yusri Hassan , Nur Hanis Mohammad Radzi
Artificial lighting consumed significant amount of electrical energy in commercial buildings. Therefore, intelligent control strategies are widely implemented to reduce the lighting energy consumption. This paper presents comprehensive review of the current sensing-based strategies (i.e. occupancy, daylight and mixed), sensors placement methods (i.e. occupancy and light) and factors affecting the performance of the lighting control strategies. Based on literature survey, the sensors placement methods can be categorized into three approaches: fixed, mathematical equation and optimization. The state-of-the-art of these approaches are discusses in details. It found that, the optimization-based approach capable to find the optimal sensor placement (numbers and positions) effectively. Moreover, the mixed strategy can be produced the highest energy savings up to 95% compared with other strategies. The occupancy pattern and building characteristics are the main factors to contribute higher energy savings of sensing-based strategies in commercial buildings.  
Volume: 16
Issue: 1
Page: 208-215
Publish at: 2019-10-01

Crowdsourcing in developing repository of phrase definition in Bahasa Indonesia

10.12928/telkomnika.v17i5.12005
Husni; Universitas Muhammadiyah Surakarta Thamrin , Gunawan; Universitas Muhammadiyah Surakarta Ariyanto , Irma; Universitas Muhammadiyah Surakarta Yuliana , Wawan Joko; Universitas Muhammadiyah Kalimantan Timur Pranoto
Language repository is valuable as a reference in using the language, its preservation, and in developing and implementation of natural language processing algorithms. Bahasa Indonesia is one of natural languages that hardly has repository despite its large number of speakers and previous attempts to build ones. We devised a way to develop repository of phrase definition in Bahasa using a kind of crowdsourcing and investigated its implementation. An application add-on was inserted to an information system that manages final year projects of undergraduate students. The add-on invites students to participate in writing keyword definition and validating definition. Investigation in a period of six months reveals that about 25% of application users take parts into the voluntary activities either as definition writers and/or validators. During the period, about 1200 phrase definitions were added into the repository and in average each definition is validated by two participants. The activity is supported by users that are well aware of the tasks, and have positive perception about the work, despite different reasons that motivate their contribution.
Volume: 17
Issue: 5
Page: 2321-2326
Publish at: 2019-10-01
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