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31,456 Article Results

Improved strategy of an MPPT based on the sliding mode control for a PV system

10.11591/ijece.v10i3.pp3074-3085
Taouni Abderrahim , Touati Abdelwahed , Majdoul Radouane
The energy produced using a photovoltaic (PV) is mainly dependent on weather factors such as temperature and solar radiation. Given the high cost and low yield of a PV system, it must operate at maximum power point (MPP), which varies according to changes in load and weather conditions. This contribution presents an improved maximum power point tracking (MPPT) controllers of a PV system in various climatic conditions. The first is a sliding mode MPPT that designed to be applied to a buck converter in order to achieve an optimal PV array output voltage. The second MPPT is based on the incremental conductance algorithm or Perturb-and-Observe algorithm. It provides the output reference PV voltage to the sliding mode controller acting on the duty cycle of the DC-DC converter. Simulation is carried out in SimPower toolbox of Matlab/Simulink. Simulation results confirm the effectiveness of the sliding mode control MPPT under the parameter variation environments and shown that the controllers meet its objectives.
Volume: 10
Issue: 3
Page: 3074-3085
Publish at: 2020-06-01

Welding station monitoring system using internet of thing (IOT)

10.11591/ijeecs.v18.i3.pp1319-1330
Ernie Mazuin Mohd Yusof , Mohd Ismail Yusof , Rafidah Ali , Izzat Hilmi Harjimi , Qasidah Kamarul Bahrin
In oil and gas industry, productivity is very important as the industry involves high cost and can be considered as a large-scale industry. Therefore, time and budget should be kept minimal to avoid loss to the oil and gas company. An example of lack of productivity in the industry is there are many complaints in the oil and gas industry that welders do not perform their job on time. Therefore, this project discussed about a system that can be used to monitor these welding stations. This system is important because it can help supervisors track the welding works from afar or anywhere using internet of things (IoT). To achieve that, a system must consist of hardware and software that are capable of connecting to the internet and monitor the welding works. In this project, the hardware chosen were Arduino Uno for data processing, ESP8266 to connect the microcontroller to the internet, voltage sensor to detect the voltage of the welding machine and a website to show the data taken. Other than that, this system was able to warn the welder of overvoltage of the welding machine. Thus, the system solved the problem of welders not performing their job on time. Supervisors were also able to monitor the job of welders to ensure maximum productivity. Based on the testing done on the system, the prototype was able to work as intended. The welding station monitoring system was able to detect welding usage, measure voltage values of welding and send the data to IoT for monitoring.
Volume: 18
Issue: 3
Page: 1319-1330
Publish at: 2020-06-01

Security-aware fair transmission scheme for 802.11 based cognitive IoT

10.11591/ijece.v10i3.pp2589-2599
Hayoung Oh
Cognitive IoT is exponentially increased because of various real time and robust applications with sensor networks and big data analysis. Each IoT protocol of network layer can be RPL, COAP and so on based on IETF standards. But still collision problems and security-aware fair transmission on top of scalable IoT devices were not solved enough. In the open wireless LAN system based cognitive IoTs, IoT node that is continuously being stripped of its transmission opportunity will continue to accumulate packets to be sent in the butter and spoofing attacks will not allow the data transfer opportunities to be fair. Therefore, in this paper, we propose a method to reduce the average wait time of all packets in the system by dynamically controlling the contention window (CW) in a wireless LAN based cognitive IoT environment where there are nodes that do not have fair transmission opportunities due to spoofing attacks. Through the performance evaluation, we have proved that the proposed technique improves up to 80% in terms of various performance evaluation than the basic WLAN 802.11 based IoT.
Volume: 10
Issue: 3
Page: 2589-2599
Publish at: 2020-06-01

Artificial fish swarm optimization algorithm for power system state estimation

10.11591/ijeecs.v18.i3.pp1130-1137
Surender Reddy Salkuti
In this paper, the power system state estimation (SE) problem is formulated as a general non-linear programming problem with equality constraints and boundary limits on the state variables. The proposed SE problem is solved using an evolutionary based Artificial Fish Swarm Optimization Algorithm (AFSOA). The AFSOA is a global search algorithm based on the characteristics of fish swarm and its autonomous model. The detailed algorithm with its flow chart is presented in this paper. To show the effectiveness of the proposed SE approach, six bus test system is considered. The obtained results are compared with other algorithms reported in the literature.
Volume: 18
Issue: 3
Page: 1130-1137
Publish at: 2020-06-01

A review of high frequency emission in 2-150 kHz range

10.11591/ijaas.v9.i2.pp132-141
Tomina Thomas , Prawin Angel Michael
This paper reviews state-of part of discussion that concern about high frequency emission. Sometimes there may be emission in the range of high frequencies because of the fast improvement of energy saving equipments in our homes. Investigators and standardized organization given a very much importance to the disturbances of power quality that occur in the range middle of 2-150 kHz. Disturbances of these high frequencies are becoming an increasing concern in the industry, particularly due to the growth of distributed and embedded generation. Now days, a large number of researches are proceeding at a large number of places, yet information regarding supraharmonics remains confined.
Volume: 9
Issue: 2
Page: 132-141
Publish at: 2020-06-01

Assessment of disturbed voltage supply effects on steady-state performance of an induction motor

10.11591/ijece.v10i3.pp2259-2270
Jamal Abdul-Kareem Mohammed , Sahar R. Al-Sakini , Arkan Ahmed Hussein
An electric power system is usually exposed to unequal and variable loads across its three phases, which leads to voltage unbalance and variation, making the three-phase voltages asymmetrical in nature at the distribution end. This problem is clearly evident in Iraq country, particularly with regard to the fluctuating voltage levels of electricity distribution during peak hours. Providing a three-phase motor with asymmetric voltages is badly affecting its working performance. Estimating the performance of this motor at steady-state under different conditions of voltage disturbances is investigated in this paper through Matlab simulation using Symmetrical component approach. The motor performance represented by active and reactive input powers, output put power, developed torque, power losses, efficiency and power factor is analyzed under full load conditions. Also, the steady-state power losses- and torque-slip characteristics at certain degrees of voltage unbalance have been calculated and plotted
Volume: 10
Issue: 3
Page: 2259-2270
Publish at: 2020-06-01

A review on region of interest-based hybrid medical image compression algorithms

10.12928/telkomnika.v18i3.14900
Suhaila Ab; Universiti Teknologi Malaysia Aziz , Suriani Mohd; Universiti Teknologi Malaysia Sam , Norliza Mohamed , Salwani Mohd; Universiti Teknologi Malaysia Daud , Siti Zaleha Abdul; Universiti Teknologi Malaysia Rashid , Hafiza; Universiti Teknologi Malaysia Abas , Muhammad Fathi; Universiti Teknologi Malaysia Yusof , Rudzidatul Akmam; Universiti Teknologi Malaysia Dziyauddin
Digital medical images have become a vital resource that supports decision-making and treatment procedures in healthcare facilities. The medical image consumes large sizes of memory, and the size keeps on growth due to the trend of medical image technology. The technology of telemedicine encourages the medical practitioner to share the medical image to support knowledge sharing to diagnose and analyse the image. The healthcare system needs to ensure distributes the medical image accurately with zero loss of information, fast and secure. Image compression is beneficial in ensuring that achieve the goal of sharing this data. The region of interest-based hybrid medical compression algorithm plays the parts to reduce the image size and shorten the time of medical image compression process. Various studies have enhanced by combining numerous techniques to get an ideal result. This paper reviews the previous works conducted on a region of interest-based hybrid medical image compression algorithms.
Volume: 18
Issue: 3
Page: 1650-1657
Publish at: 2020-06-01

Implementation of persuasive design principles in mobile application development: a qualitative study

10.11591/ijeecs.v18.i3.pp1464-1473
Nor Afifah Shafin , RD Rohmat Saedudin , Nor Hazana Abdullah
Persuasive design principles (PDP) of persuasive system features framework have shown impressive results from the context of user engagement and acceptance as well as continuous usage towards the persuasive systems involved. Yet, available literatures do not thoroughly address the implementation of these design principles specifically in mobile applications and there is insufficient discussion on the impact of the principles in relation to the overall achievement of mobile applications. Hence, this research was conducted with the aim to qualitatively explore the way PDP were implemented across three different levels of mobile applications’ attainment. For this study, seven semi-structured interviews were conducted with the involvement of fifteen (15) Android mobile applications in the area of utilities category. These mobile applications were then categorized into three categories which is successful, partially successful and less successful based on their numbers of mobile applications downloaded for three consecutive years. The results from the content analysis revealed that each of the PDP were implemented in many ways yet the most common applied principles are reduction, tailoring and personalization. However, the analysis also shows low numbers of implementation from the system credibility and social support category. In addition, most of the mobile applications of the successful category have implemented a lot more PDP as compared to the other two mobile application categories. The results from this study has provide significance towards developers, practitioners as well as the scholars from the contextual perspective of persuasive system framework also the practical values of the principles specifically the implementation in mobile application development.
Volume: 18
Issue: 3
Page: 1464-1473
Publish at: 2020-06-01

Fitting statistical distribution of extreme rainfall data for the purpose of simulation

10.11591/ijeecs.v18.i3.pp1367-1374
S.M. Shaharudin , N Ahmad , N.S. Mohamed , Hairulnizam Mahdin
In this study, several types of probability distributions were used to fit the daily torrential rainfall data from 15 monitoring stations of Peninsular Malaysia from the period of 1975 to 2007. The study of fitting statistical distribution is important to find the most suitable model that could anticipate extreme events of certain natural phenomena such as flood and tsunamis. The aim of the study is to determine which distribution fits well with the daily torrential Malaysian rainfall data. Generalized Pareto, Lognormal and Gamma distributions were the distributions that had been tested to fit the daily torrential rainfall amount in Peninsular Malaysia. First, the appropriate distribution of the daily torrential rainfall was identified within the selected distributions for rainfall stations. Then, data sets were generated based on probability distributions that mimic a daily torrential rainfall data. Graphical representation and goodness of fit tests were used in finding the best fit model. The Generalized Pareto was found to be the most appropriate distribution in describing the daily torrential rainfall amounts of Peninsular Malaysia. The outputs can be beneficial for the purpose of generating several sets of simulated data matrices that mimic the same characteristics of rainfall data in order to assess the performance of the modification method compared to classical method. 
Volume: 18
Issue: 3
Page: 1367-1374
Publish at: 2020-06-01

Architecture of the global navigation satellite system for maritime applications

10.12928/telkomnika.v18i3.15640
Dimov Stojce; Durban University of Technogy Ilcev
This paper introduces architecture of the global navigation satellite system (GNSS) networks in the function of the maritime space communications, navigation and surveillance (CNS) for enhanced navigation and positioning of vessels deploying passive, active and hybrid global determination satellite systems (GDSS) networks. These GNSS networks have to enhance safety and control oceangoing ships in navigation across the ocean and inland waters, to improve logistics and freight of goods, security of crew and passengers onboard ships. The maritime GNSS networks integrated with geostationary earth orbit (GEO) satellite constellations are providing important global satellite augmentation systems (GSAS) architecture, which is established by two first generations known GNSS as GNSS-1 infrastructures. The GNSS-1 network is the composition of two subnets such as the US global position system (GPS) and Russian global satellite navigation system (GLONASS). Both GNSS-1 networks play a significant contribution in very precise timing, tracking, guidance, determination and navigation of the oceangoing ships. At this point, both GNSS-1 networks, GPS and GLONASS, are used in maritime and many other mobile and fixed applications to provide enhanced accuracy and high integrity monitoring usable for positioning of the oceangoing ships. To provide improvements of GNSS-1 network it will be necessary to carry out their augmentation within several regional satellite augmentation systems (RSAS) as integration parts of GSAS infrastructures.
Volume: 18
Issue: 3
Page: 1600-1609
Publish at: 2020-06-01

Effect of fiber and solenoid variation parameters on the elements of a corrector PID for electromagnetic fiber squeezer based polarization controller

10.11591/ijece.v10i3.pp2441-2451
Abdallah Zahidi , Amrane said , Nawfel Azami , Naoual Nasser
Controlling the polarization of the light output from single-mode fiber systems is very important for connecting it to polarization-dependent integrated optical circuits, while applications using a heterodyne detection system. Polarization controller using fiber squeezer is attractive for a low-loss, low-penalty coherent optical fiber trunk system. However, for polarization controllers using electromagnetic fiber squeezer, the stability problem due to the saturation of their magnetic circuit must be studied. In fact, in their conventional configuration, open-loop stability affects performance and limits applications. First at all, this effect has been analyzed and a feedback circuit with correctors has been proposed to improve stability performance. Then a simulation study is proposed to examine the influence of the system parameters on the corrector constants. The results of the simulation show that if the system parameters change the constants Kp, Ki and Kd of the PID corrector must be adjusted to keep an optimized dynamic response.
Volume: 10
Issue: 3
Page: 2441-2451
Publish at: 2020-06-01

Visual art teachers’ determination of the self sufficiency to use alternative assessment tools

10.11591/ijere.v9i2.20496
Sehran Dilmaç , Oğuz Dilmaç
The aim of this study was to examine visual arts teachers’ opinions on determination and evaluation of self-efficacy beliefs concerning using to alternative assessment tools. In this study ‘the survey research model’ from descriptive research was used in which the aim was to determine the opinions of visual arts teachers about the alternative assessment evaluation. A descriptive survey model was used as the quantitative research method. Data was obtained through a Likert scale that is also named as ‘Progression File, Performance Assessment and using the Grading Key Sufficiency Scale by the Visual Arts Teachers’. The study is conducted with 123 visual art teachers in the Turkey in the 2018-2019 academic years. Progression File, Performance Assessment and using the Grading Key Sufficiency Scale was applied to Visual Arts Teachers. It was determined that most of the teachers found themselves adequate about the evaluation process.
Volume: 9
Issue: 2
Page: 292-302
Publish at: 2020-06-01

Faulty sensor detection using multi-variate sensors in internet of things (IoTs)

10.11591/ijeecs.v18.i3.pp1391-1399
Khaldoon Ammar Omar , Ahmed Dhahir Malik , Ansar Jamil , Hasan Muwafeq Gheni
IoT devices are lightweight and have limited computational capabilities often exposed to harsh environments, which can cause failure on the IoT devices [1, 2].  The failure on the IoT devices is also caused due to limited battery life, hardware failure or human mistakes. Sensor faults can be categorized under one type of hardware failure, such as sensor burn, reduced sensor sensitivity and malfunctioned sensors.  Any faulty on the IoT devices can cause a problem on the overall operation of the IoT system. Traditional ways in the management of IoT devices is a maintenance officer require to check each device every day  [1, 3]. Any faulty devices found needs to be fixed or replaced. This traditional method is not practical and very challenging especially in the management of a large scale deployment of IoT consist of hundreds or thousands devices. Because of this, we proposed a faulty sensor detection and identification mechanism using multivariate sensors. Two methods of decision making are introduced in detecting faulty sensors, which are logical and correlation method that implemented in smart parking system and smart agriculture system accordingly. The logical method compares state of all sensors (ultrasound, IR and hall-effect) in the smart parking system either a parking lot is occupied or available, and then determine the condition of the sensors. The drawback of this method is not able to detect faulty sensor properly for a constant fault, which the sensor reading remains the same value. The correlation method calculates the correlation between all sensors (soil moisture, soil temperature and soil water) in the smart agriculture system. This method uses a moving window technique to calculate the correlation for all sensor over time. Any incomparable and uncorrelated sensor readings means a presence of faulty sensors. Based on the experiment results, the findings shows that the proposed faulty sensor detection mechanism is working properly in detecting faulty sensor in a timely manner.
Volume: 18
Issue: 3
Page: 1391-1399
Publish at: 2020-06-01

Contour evolution method for precise boundary delineation of medical images

10.12928/telkomnika.v18i3.14746
Friska; Universitas Multimedia Nusantara Natalia , Hira; Universitas Multimedia Nusantara Meidia , Nunik; Universitas Multimedia Nusantara Afriliana , Julio Christian; Universitas Multimedia Nusantara Young , Sud; Universitas Multimedia Nusantara Sudirman
Image segmentation is an important precursor to boundary delineation of medical images. One of the major challenges in applying automatic image segmentation in medical images is the imperfection in the imaging process which can result in inconsistent contrast and brightness levels, and low image sharpness and vanishing boundaries. Although recent advances in deep learning produce vast improvements in the quality of image segmentation, the accuracy of segmentation around object boundaries still requires improvement. We developed a new approach to contour evolution that is more intuitive but shares some common principles with the active contour model method. The method uses two concepts, namely the boundary grid and sparse boundary representation, as an implicit and explicit representation of the boundary points. We tested our method using lumbar spine MRI images of 515 patients. The experiment results show that our method performs up to 10.2 times faster and more flexible than the geodesic active contours method. Using BF-score contour-based metric, we show that our method improves the boundary accuracy from 74% to 84% as opposed to 63% by the latter method.
Volume: 18
Issue: 3
Page: 1621-1632
Publish at: 2020-06-01

OFDM synchronization system using wavelet transform for symbol rate detection

10.12928/telkomnika.v18i3.14834
Masaru; Waseda University Sawada , Quang Ngoc; Waseda University Nguyen , Mohammed Mustafa; Waseda University Alhasani , Cutifa; President University Safitri , Takuro; Waseda University Sato
In radio communications, using wavelet signal analysis to recover the symbol rate timing clock of orthogonal frequency-division multiplexing (OFDM) is a new approach that can tolerate signal distortion from intersymbol interference (ISI) and intercarrier interference of encoding digital data on multiple carrier frequencies. Typically, the reception synchronization with wavelet signal analysis in OFDM can improve the performance over the fourier transform-based OFDM. However, a synchronization procedure that is stable against distortion and noise is essential to diminish the symbol synchronization establishment and operation sampling period. In this paper, we propose an OFDM synchronization system and analyze the impact of the wavelet denoise procedure on the OFDM system, which extracts the symbol rate of the OFDM frame. The evaluation results show that the proposed system can optimize the frequency window size to enable an efficient timing and frequency offset estimation with high and stable performance in terms of bit error rate (BER) and Frame Error Rate (FER) especially when the value of EbN0 (a normalized signal-to-noise ratio SNR measure) is greater than 8 dB, thanks to the wavelet transform.
Volume: 18
Issue: 3
Page: 1658-1670
Publish at: 2020-06-01
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