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Roopali Agarwal, Manoj K. Shukla
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp992-998

Abstract:
In OFDM-IDMA scheme, intersymbol interference (ISI) is resolved by the OFDM layer and multiple access interference (MAI) is suppressed by the IDMA layer at low cost . However OFDM-IDMA scheme suffers high peak-to-average power ratio (PAPR) problem. For removing high PAPR problem a hybrid multiple access scheme SC-FDM-IDMA has been proposed. In this paper, bit error rate (BER) performance comparison of SC-FDM-IDMA scheme, OFDM-IDMA scheme and IDMA scheme have been duly presented. Moreover, the BER performance of various subcarrier mapping methods for SC-FDM-IDMA scheme as well as other results with variation of different parameters have also been demonstrated. Finally simulation result for BER performance improvement has been shown employing BCH code. All the simulation results demonstrate the suitability of SC-FDM-IDMA scheme for wireless communication under AWGN channel environment.
, Zuwairie Ibrahim, Marizan Mubin, Sophan Wahyudi Nawawi
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1611-1619; https://doi.org/10.11591/ijece.v7i3.pp1611-1619

Abstract:
A new variation of particle swarm optimization (PSO) termed as transitional PSO (T-PSO) is proposed here. T-PSO attempts to improve PSO via its iteration strategy. Traditionally, PSO adopts either the synchronous or the asynchronous iteration strategy. Both of these iteration strategies have their own strengths and weaknesses. The synchronous strategy has reputation of better exploitation while asynchronous strategy is stronger in exploration. The particles of T-PSO start with asynchronous update to encourage more exploration at the start of the search. If no better solution is found for a number of iteration, the iteration strategy is changed to synchronous update to allow fine tuning by the particles. The results show that T-PSO is ranked better than the traditional PSOs.
Oulhaj Otman, Naima A. Touhami, Mohamed Aghoutane, Abdelmounaim Belbachir Kchairi
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i4.pp1850-1857

Abstract:
In this work, we present a new configuration of a new miniature microstrip antenna array having a wide frequency band and with a circular polarization. The bandwidth is about 2GHz for a reflection coefficient under -10dB and centered on the ISM ‘Industrial Scientific Medical’ band at 5.8 GHz. To design such array, we have started the design by validating one antenna element at 10 GHz and after that by using the technique of defected ground, we have validated the antenna array in the frequency band [4 GHz -6 GHz] which will permit to miniature the dimensions. The final fabricated antenna array is mounted on an FR4 substrate, the whole area is 102.48 X 31.39 mm2 with a gain of 5dBi at 4GHz.
, Nasrin M. Makbol, Sam Yin Yee
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1594-1601; https://doi.org/10.11591/ijece.v7i3.pp1594-1601

Abstract:
Nowadays, face recognition becomes one of the important topics in the computer vision and image processing area. This is due to its importance where can be used in many applications. The main key in the face recognition is how to extract distinguishable features from the image to perform high recognition accuracy. Local binary pattern (LBP) and many of its variants used as texture features in many of face recognition systems. Although LBP performed well in many fields, it is sensitive to noise, and different patterns of LBP may classify into the same class that reduces its discriminating property. Completed Local Ternary Pattern (CLTP) is one of the new proposed texture features to overcome the drawbacks of the LBP. The CLTP outperformed LBP and some of its variants in many fields such as texture, scene, and event image classification. In this study, we study and investigate the performance of CLTP operator for face recognition task. The Japanese Female Facial Expression (JAFFE), and FEI face databases are used in the experiments. In the experimental results, CLTP outperformed some previous texture descriptors and achieves higher classification rate for face recognition task which has reached up 99.38% and 85.22% in JAFFE and FEI, respectively.
Sangsoon Lim
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp986-991

Abstract:
Cognitive radio networks provide dynamic spectrum access techniques to support the increase in spectrum demand. In particular, the spectrum sharing among primary and secondary users can improve spectrum utilization in unused spectrum by primary users. In this paper, we propose a novel game theoretic channel allocation framework to maximize channel utilization in cognitive radio networks. We degisn the utility function based on the co-channel interference among primary and secondary users. In addition, we embed the property of the adjacent channel intererence to consider real wireless environment. The results show that the utility function converges quickly to Nash equilibrium and achieves channel gain by up to 25 dB compared to initial assignment.
Siti Fatimaah Sulaiman, M.F. Rahmat, A.A.M. Faudzi, Khairuddin Osman, Sy Najib Sy Salim, S.I. Samsudin, A.R. Azira
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1633-1642; https://doi.org/10.11591/ijece.v7i3.pp1633-1642

Abstract:
This paper demonstrates the effectiveness of applying constraints in a controller algorithm as a strategy to enhance the pneumatic actuator system’s positioning performance. The aim of the present study is to reduce the overshoot in the pneumatic actuator positioning system’s response. An autoregressive with exogenous input (ARX) model structure has been used to model the pneumatic system, while a model predictive control (MPC) has been employed as a control strategy. The input constraint has been applied to the control signals (on/off valves signals) to ensure accurate position tracking. Results show that the strategy with constraint effectively reduced overshoot by more than 99.0837 % and 97.0596 % in simulation and real-time experiments, respectively. Moreover, the performance of the proposed strategy in controlling the pneumatic positioning system is considered good enough under various loads. The proposed strategy can be applied in any industry that used pneumatic actuator in their applications, especially in industries that involved with position control such as in manufacturing, automation and robotics. The strategy proved to be capable of controlling the pneumatic system better, especially in the real-time environment.
Siti Sufiah Abd Wahid, Mohd Fikri Hilmi Mohd Taib, , Mohd Hafizi Ahmad, Noor Azlinda Ahmad, , Zuraimy Adzis, Mohd Hafiez Izzwan Saad
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i3.pp1588-1593

Abstract:
Insulation is one of the most important parts in high voltage apparatus such as power transformer. Most power transformer use liquid insulation material, known as power transformer oil. Petroleum-based oil so called mineral oil has been used for many years as power transformer oil. This is due to its high dielectric field strength, low dielectric loses and good long-term performance. This research work has been carried out to investigate the effect of thermal accelerated ageing on electrical properties for several vegetative-based oils. The oil samples that have been used in this research work are soy bean-based oil (FR3) and commercial palm-based oil (PFAE). As comparison, Hyrax mineral oil has also been investigated. The results revealed that vegetative-based oils have as well as dielectric strength compared with mineral oil. It was found that the dielectric strength for all oil samples decreased when undergo the thermal accelerated ageing process.
Sabriansyah Rizqika Akbar, Maystya Tri Handono, Achmad Basuki
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp1012-1022

Abstract:
Pervasive technology is an important feature in smart home appliances control. With pervasive technology, the user is able to discover and control every device and each service without initialization configuration and setup. Since single-board computer often used in smart home appliances, combining pervasive technology and microcomputer/single-board computer will be important to be applied and make a possibility to create a smart home system based on the requirement of it users that will be beneficial for the smart home users and the developers. This paper proposed a design of pervasive discovery, service, and control system for smart home appliances by integrating Raspberry Pi, UPnP protocols, and Xbee that able to control an RGB LED services such as switching, dimming, change color and read a temperature sensor as an example in smart home appliances. This paper enriched the raspberry Pi GPIO function to be able to control via TCP/IP network with UPnP protocol and receive information from a temperature sensor node via Xbee communication. Service control time is measured with UPnP round trip time by subtracting HTTP response arrival with HTTP request time. GPIO processing time measured at the application level by counting a timer that starts before GPIO process and ended after GPIO successfully executed.
M. S. Zainudin, M. K. A. Rahim, ,
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i3.pp1574-1579

Abstract:
The E-field absorbance performance of various metamaterial absorber structure is presented. The study started from the simulation of various design patch of metamaterial absorber. The performances are measured from the reflection coefficient, percentage of absorption, value of E-field and the surface current for circle, square and hexagon patch design of metamaterial absorber. From the simulation, it is shown that the circle patch design shows the most reliable design for harvest energy with the absorption of 99.85% and highest E-field concentration of 2.07 × 105 V/m.
, M. K. A. Rahim, I. M. Qureshi, N. A. Murad
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp961-966

Abstract:
In this work, differential evolution based compressive sensing technique for detection of faulty sensors in linear arrays has been presented. This algorithm starts from taking the linear measurements of the power pattern generated by the array under test. The difference between the collected compressive measurements and measured healthy array field pattern is minimized using a hybrid differential evolution (DE). In the proposed method, the slow convergence of DE based compressed sensing technique is accelerated with the help of parallel coordinate decent algorithm (PCD). The combination of DE with PCD makes the minimization faster and precise. Simulation results validate the performance to detect faulty sensors from a small number of measurements.
Nurazizah Mahmod, Norhaliza Abdul Wahab
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1568-1573; https://doi.org/10.11591/ijece.v7i3.pp1568-1573

Abstract:
Aerobic Granular Sludge (AGS) technology is a promising development in the field of aerobic wastewater treatment system. Aerobic granulation usually happened in sequencing batch reactors (SBRs) system. Most available models for the system are structurally complex with the nonlinearity and uncertainty of the system makes it hard to predict. A reliable model of AGS is essential in order to provide a tool for predicting its performance. This paper proposes a dynamic neural network approach to predict the dynamic behavior of aerobic granular sludge SBRs. The developed model will be applied to predict the performance of AGS in terms of the removal of Chemical Oxygen Demand (COD). The simulation uses the experimental data obtained from the sequencing batch reactor under three different conditions of temperature (30˚C, 40˚C and 50˚C). The overall results indicated that the dynamic of aerobic granular sludge SBR can be successfully estimated using dynamic neural network model, particularly at high temperature.
Satheesh K S V A Kavuri, Gangadhara Rao Kancherla, Basaveswararao Bobba
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp950-960

Abstract:
Cloud computing is a distributed architecture where user can store their private, public or any application software components on it. Many cloud based privacy protection solutions have been implemented, however most of them only focus on limited data resources and storage format. Data confidentiality and inefficient data access methods are the major issues which block the cloud users to store their high dimensional data. With more and more cloud based applications are being available and stored on various cloud servers, a novel multi-user based privacy protection mechanism need to design and develop to improve the privacy protection on high dimensional data. In this paper, a novel integrity algorithm with attribute based encryption model was implemented to ensure confidentiality for high dimensional data security on cloud storage. The main objective of this model is to store, transmit and retrieve the high dimensional cloud data with low computational time and high security. Experimental results show that the proposed model has high data scalability, less computational time and low memory usage compared to traditional cloud based privacy protection models.
N. A. Elias, , M. K. A. Rahim, C. J. Panagamuwa, W. Whittow
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i3.pp1546-1553

Abstract:
In this work, the antenna performance and Specific Absorption Rate (SAR) levels in a homogeneous phantom exposed to 900 MHz flexible diamond dipole antenna are investigated under different crumpling deformation conditions. The numerical simulations of the realistic complex two dimensional crumpling are performed by using Finite Integration Technique (FIT) which is applied in Computer Simulation Technology (CST) Microwave Studio. The validation of results with the industry standard DASY4 robot SAR measurement system is made possible with the use of homogenous phantom model. The 1 g, 10 g and point SAR are enhanced by 28.33 %, 36.75 % and 9.55 % respectively due to the antenna crumpling deformation. The short length ripple investigated in this paper shows the highest relative SAR increment.
Ahmad Hafiz Mohamad Razy, , , Norlaili Mohd Noh
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp926-932

Abstract:
In this work, a tunable ferrofluid-based polydimethylsiloxane (PDMS) microchannel inductor with high quality factor and high tuning range is proposed. For this project, PDMS is used to create a microchannel with a width and height of 0.53 mm and 0.2 mm respectively. The microchannel is then used to cover the whole design of a solenoid inductor. A solenoid inductor is designed using wire bonding technique where lines of copper and bond wires are used to form a solenoid winding on top of silicon substrate. A light hydrocarbon based ferrofluid EMG 901 660 mT with high permeability of 5.4 is used. The ferrofluid-based liquid is injected into the channel to enhance the performance of a quality factor. A 3D full-wave electromagnetic fields tool, ANSYS HFSS is used in this work to simulate the solenoid inductor. The results obtained in this work gives a quality factor of more than 10 at a frequency range of 300 MHz to 3.3 GHz (Ultra High Frequency range). The highest quality factor is 37 which occurs at a frequency of 1.5 GHz, provides a high tuning range of 112%.
Muataz Watheq Sabri, N A Murad, M K A Rahim
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp888-893

Abstract:
This paper focuses on the design of a Wideband Branch Line Coupler by using open circuits coupled lines technique. The design is implemented by adding four open circuits coupled lines to the structure of the Conventional Branch Line Coupler. The proposed design of Wideband Branch Line Coupler is simulated using CST microwave software. The simulation results show that the coupler is operated at 3.8 GHz with coupling factor of -3dB and 90̊ phase difference between the two output ports. The prototype is fabricated and measured to validate the simulated results. A similar Wide Bandwidth is observed on simulation and measurement. The structure achieved a fractional bandwidth of 42.63%, and return loss of 21 dB compared to the Conventional Branch Line Coupler (BLC).
Nur Rabiul Liyana Mohamed, Ansar Jamil, Lukman Hanif Audah Audah, Jiwa Abdullah, Rozlan Alias
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp942-949

Abstract:
Wireless Sensor Network (WSN) is a promising technology in Internet of Things (IoTs) because it can be implemented in many applications. However, a main drawback of WSN is it has limited energy because each sensor node is powered using batteries. Therefore, duty-cycle mechanisms are introduced to reduce power consumption of the sensor nodes by ensuring the sensor nodes in the sleep mode almost of the time in order to prolong the network lifetime. One of the de-facto standard of duty-cycle mechanism in WSN is ContikiMAC, which is the default duty-cycle mechanism in Contiki OS. ContikiMAC ensures nodes can participate in network communication yet keep it in sleep mode for roughly 99\% of the time. However, it is found that the ContikiMAC does not perform well in dynamic network conditions. In a bursty network, ContikiMAC provides a poor performance in term of packet delivery ratio, which is caused by congestion. One possible solution is ContikiMAC should increase its duty-cycle rate in order to support the bursty traffic. This solution creates a non-uniform duty-cycle rates among the sensor nodes in the network. This work aims to investigate the effect of non-uniform duty-cycle rates on the performance on ContikiMAC. Cooja simulator is selected as the simulation tool. Three different simulation scenarios are considered depending on the Clear Channel Assessment Rate (CCR) configurations: a low uniform CCR value (Low-CCR), a high uniform CCR value (High-CCR) and non-uniform CCR values (Non-uniform-CCR). The simulation results show that the Low-CCR scenario provides the worst performance of PDR. On the other hand, the High-CCR scenario provides the best performance of PDR. The Non-uniform-CCR provides PDR in between of Low-CCR and High-CCR.
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp933-941

Abstract:
Conservation of the energy is one of the main design issues in wireless sensor networks. The limited battery power of each sensor node is a challenging task in deploying this type of network. The challenge is crucial in reliable wireless network when implementing efficient error correcting scheme with energy consuming routing protocol. In this work, we investigated the energy performance of LDPC code in multi-hop wireless sensor network. We proposed a model of two base stations to prolong the lifetime and build a reliable and energy-efficient network. Through performed MATLAB simulations, we examine the energy effectiveness of multiple base stations model on reliable wireless sensor network performance in different network dimensions.
Noor ‘Aliaa Awang, Faris Akmal Suhaini, , Mohd Hafizi Ahmad, Noor Azlinda Ahmad, , Zuraimy Adzis
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i3.pp1562-1567

Abstract:
Partial discharge (PD) may lead to the degradation of insulating materials and affect the lifetime of high voltage equipment. This paper describes the effect of relative humidity on PD characteristic of epoxy/boron nitride (BN) nanocomposite under high voltage (HV) stress. In this work, CIGRE Method II was utilized as an electrode configuration. BN nanofiller was chosen because of its high insulating properties with high thermal conductivity. The PD characteristics such as PD charge magnitude, PD number or occurrence, and average of PD charge during certain of ageing time under HV stress against relative humidity were examined. The results revealed that PD number of humid samples is higher about 8~14% compared to the normal ones. It is considered due to the decrease of surface resistance of the humid samples. The PD charge magnitudes of humid samples are slightly higher compared to the normal ones. The epoxy/BN nanocomposite has lesser PD number and magnitude compared to the neat epoxy samples.
S. Doucha, M. Abri, H. Abri Badaoui, B. Fellah
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 3467-3474; https://doi.org/10.11591/ijece.v7i6.pp3467-3474

Abstract:
A new type of leaky-wave antenna (LWA) using half-mode substrate integrated waveguide (HMSIW) as the base structure is proposed in this paper. The structure consists of an array of slot, antenna designed to operate in X band applications from 8 to 12 GHz. HMSIW preserves nearly all the advantages of SIW whereas its size is nearly reduced by half. The antenna radiates one main beam that can be steered from the backward to the forward direction by changing frequency.
, Agus Zainal Arifin,
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i6.pp3705-3710

Abstract:
One of the most common issue in information retrieval is documents ranking. Documents ranking system collects search terms from the user and orderly retrieves documents based on the relevance. Vector space models based on TF.IDF term weighting is the most common method for this topic. In this study, we are concerned with the study of automatic retrieval of Islamic Fiqh (Law) book collection. This collection contains many books, each of which has tens to hundreds of pages. Each page of the book is treated as a document that will be ranked based on the user query. We developed class-based indexing method called inverse class frequency (ICF) and book-based indexing method inverse book frequency (IBF) for this Arabic information retrieval. Those method then been incorporated with the previous method so that it becomes TF.IDF.ICF.IBF. The term weighting method also used for feature selection due to high dimensionality of the feature space. This novel method was tested using a dataset from 13 Arabic Fiqh e-books. The experimental results showed that the proposed method have the highest precision, recall, and F-Measure than the other three methods at variations of feature selection. The best performance of this method was obtained when using best 1000 features by precision value of 76%, recall value of 74%, and F-Measure value of 75%.
Bandana Mahapatra,
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 919-925; https://doi.org/10.11591/ijece.v7i2.pp919-925

Abstract:
Security is considered as one of the major challenge when it comes to infrastructure less and self dependent network without any centralized control. The vulnerability of Adhoc Network makes it susceptible to external attacks like flooding of hello messages or propagating fake routing messages etc. Such attacks generates a variety of problems like disturbing the network by flooding messages that results in waste of battery which is a vital resource to maintain the life span of the network. Most importantly cause agents to die when unable to reach destination due to fake routing messages causing a heavy loss on part of the nodes generating them to maintain the route knowledge. The paper proposes a novel technique to identify the flooding attack and measure to overcome them using Multi-Agent system.
, Mohsen Ahmadnia, Hamid Reza Tavakoli
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i6.pp3446-3453

Abstract:
In this paper, the synchronization problem of T chaotic system and Lu chaotic system is studied. The parameter of the drive T chaotic system is considered unknown. An adaptive projective lag control method and also parameter estimation law are designed to achieve chaos synchronization problem between two chaotic systems. Then Lyapunov stability theorem is utilized to prove the validity of the proposed control method. After that, some numerical simulations are performed to assess the performance of the proposed method. The results show high accuracy of the proposed method in control and synchronization of chaotic systems.
M. A. Zulkifeli, , S. Taking, N. A. Azmi, S. S. Jamuar
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i3.pp1554-1561

Abstract:
A Metal-Insulator-Metal (MIM) capacitor with high capacitance, high breakdown voltage, and low leakage current is aspired so that the device can be applied in many electronic applications. The most significant factors that affect the MIM capacitor’s performance is the design and the dielectric materials used. In this study, MIM capacitors are simulated using different dielectric materials and different number of dielectric layers from two layers up to seven layers. The effect of the different dielectric constants (k) to the performance of the MIM capacitors is also studied, whereas this work investigates the effect of using low-k and high-k dielectric materials. The dielectric materials used in this study with high-k are Al2O3 and HfO2, while the low-k dielectric materials are SiO2 and Si3N4. The results demonstrate that the dielectric materials with high-k produce the highest capacitance. Results also show that metal-Al2O3 interfaces increase the performance of the MIM capacitors. By increasing the number of dielectric layers to seven stacks, the capacitance and breakdown voltage reach its highest value at 0.39 nF and 240 V, respectively.
, Robert Bicker
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 3421-3435; https://doi.org/10.11591/ijece.v7i6.pp3421-3435

Abstract:
Industrial robots are now commonly used in production systems to improve productivity, quality and safety in manufacturing processes. Recent developments involve using robots cooperatively with production line operatives. Regardless of application, there are significant implications for operator safety in the event of a robot malfunction or failure, and the consequent downtime has a significant impact on productivity in manufacturing. Machine healthy monitoring is a type of maintenance inspection technique by which an operational asset is monitored and the data obtained is analysed to detect signs of degradation and thus reducing the maintenance costs. Developments in electronics and computing have opened new horizons in the area of condition monitoring. The aim of using wireless electronic systems is to allow data analysis to be carried out locally at field level and transmitting the results wirelessly to the base station, which as a result will help to overcome the need for wiring and provides an easy and cost-effective sensing technique to detect faults in machines. So, the main focuses of this research is to develop an online and wireless fault detection system for an industrial robot based on statistical control chart approach. An experimental investigation was accomplished using the PUMA 560 robot and vibration signal capturing was adopted, as it responds immediately to manifest itself if any change is appeared in the monitored machine, to extract features related to the robot health conditions. The results indicate the successful detection of faults at the early stages using the key extracted parameters.
Suharjito Suharjito, Jimmy Jimmy,
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i6.pp3683-3691

Abstract:
Determination of nutritional status is closely related to the determination of dietary patterns should be given to infants. Nutrition is very important role in mental, physical development, and human productivity. In this study, the system based on android is developed to determine the nutritional status of infants by using Fuzzy Sugeno. Indicator variables are age, height, circle head, and body weight according to the male or female. In this study, the results of measurements of nutritional status of children with Fuzzy Sugenoare tested by comparing the nutritional quality of the data Posyandu toddler by using anthropometric tables. The results of the evaluation measurement accuracy in this application are compared with the results of manual calculation based infant growth charts according to WHO standards. Therefore, these applications can be used to help the community in monitoring the nutritional status of children so that the growth of children is more appropriate in line with expectations.
Jawadi Samir, Ben Slama Sami, Cherif Adnane
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i4.pp1789-1796

Abstract:
PEMFC powered Hybrid vehicle system is one of an interesting issue for the industry due to its high performances. The PEMFC cannot certainly ensure a sustained required energy in some scenarios. To solve this problem related to PEMFC transient response, a Hybrid Electrical Storage System (HES) is a potential candidate for a solution. The proposed Hybrid Storage system is comprised of the battery (BT) and a Super-Capacitor (SC) components. These components are included to control the hydrogen variations and the fast peak powers scenarios respectively. The SC is used to control PEMFC and the BT slow dynamics at the same times. An accurate Multi-Ways Energy Management System (MW-EMS) is proposed which aims to cooperate with the system components through SC/BT state of charge and a flux calculation. The simulation results are discussed and assessed using MATLAB/ Simulink.
Fatemeh Hourali, Sorayya Gharravi
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i5.pp2895-2901

Abstract:
Human recognition systems have gained great importance recently in a wide range of applications like access, control, criminal investigation and border security. Ear is an emerging biometric which has rich and stable structure and can potentially be implemented reliably and cost efficiently. Thus human ear recognition has been researched widely and made greatly progress. High recognition rates which are reported in most existing methods can be reached only under closely controlled conditions. Actually a slight amount of rotation and translation which is inescapable would be injurious for system performance. In this paper, a method that uses a transformed type of DCT is implemented to extract meaningful features from ear images. This algorithm is quite robust to ear rotation, translation and illumination. The proposed method is experimented on two popular databases, i.e. USTB II and IIT Delhi II, which achieves significant improvement in the performance in comparison to other methods with good efficiency based on LBP, DSIFT and Gabor. Also because of considering only important coefficients, this method is faster compared to other methods.
H. Rosli, N. A. Othman, N. A. M. Jamail, M. N. Ismail
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i6.pp3114-3123

Abstract:
Overhead line insulators can be damaged for various reasons during their service life. Porcelain or glass insulators once damaged can affect the reliability of power system networks. This paper presents the study of voltage and electric characteristics along the surface of a broken porcelain insulator located in a string of 10 unit insulators. Three models of broken porcelain insulators were being proposed and the analysis results on voltage and electric characteristics were individually collected. The broken porcelain insulator with the most significant effect were then being investigated in the strings of 10 unit insulators. The finite element software of Quickfield was used to analyze the voltage and electric characteristics. Form the presented results, it is proven that the single porcelain insulators with broken shed at the nearest to the electrode terminal gave the most significant effect of voltage and electric field distribution pattern along the creepage distance. However, when this type of broken insulator was included in a string of 10 unit insulators, maximum average value of voltage achieved once the broken insulator was located at the HV terminal. Meanwhile, the highest electric field strength was recorded when the broken insulator was located in the middle of the string.
Prakash P, Darshaun K. G., Yaazhlene. P, Medidhi Venkata Ganesh, Vasudha B
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 3669-3673; https://doi.org/10.11591/ijece.v7i6.pp3669-3673

Abstract:
In Cloud Computing, all the processing of the data collected by the node is done in the central server. This involves a lot of time as data has to be transferred from the node to central server before the processing of data can be done in the server. Also it is not practical to stream terabytes of data from the node to the cloud and back. To overcome these disadvantages, an extension of cloud computing, known as fog computing, is introduced. In this, the processing of data is done completely in the node if the data does not require higher computing power and is done partially if the data requires high computing power, after which the data is transferred to the central server for the remaining computations. This greatly reduces the time involved in the process and is more efficient as the central server is not overloaded. Fog is quite useful in geographically dispersed areas where connectivity can be irregular. The ideal use case requires intelligence near the edge where ultra-low latency is critical, and is promised by fog computing. The concepts of cloud computing and fog computing will be explored and their features will be contrasted to understand which is more efficient and better suited for real-time application.
Syahira Ibrahim, Norhaliza Abdul Wahab, Aznah Nor Anuar, Mustafa Bob
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i3.pp1522-1529

Abstract:
This paper proposes an improved optimisation of sequencing batch reactors (SBR) for aerobic granular sludge (AGS) at high temperature-low humidity for domestic wastewater treatment using response surface methodology (RSM). The main advantages of RSM are less number of experiment required and suitable for complex process. The sludge from a conventional activated sludge wastewater treatment plant and three sequencing batch reactors (SBRs) were fed with synthetic wastewater. The experiment were carried out at different high temperatures (30, 40 and 50°C) and the formation of AGS for simultaneous organics and nutrients removal were examined in 60 days. RSM is used to model and to optimize the biological parameters for chemical oxygen demand (COD) and total phosphorus removal in SBR system. The simulation results showed that at temperature of 45.33°C give the optimum condition for the total removal of COD and phosphorus, which correspond to performance index R2 of 0.955 and 0.91, respectively.
, Byamakesh Nayak, K.B. Mohanty
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i5.pp2392-2400

Abstract:
Photovoltaic (PV) module parameters act an important task in PV system design and simulation. Most popularly used single diode Rsh model has five unknown electrical parameters such as series resistance (Rse), shunt resistance (Rsh), diode quality factor (a), photo-generated current (Ipg) and dark saturation current (Is) in the mathematical model of PV module. The PV module output voltage and current relationship is represented by a transcendental equation and is not possible to solve analytically. This paper proposes nonlinear least square (NLS) technique to extract five unknown parameters. The proposed technique is compared with other two popular techniques available in the literature such as Villalva’s comprehensive technique and modified Newton-Raphson (N-R) technique. Only two parameters Rse and Rsh are estimated by Villalva’s technique, but all single diode unknown electrical parameters can be estimated by the NLS technique. The accuracy of different estimation techniques is compared in terms of absolute percentage errors at MPP and is found the minimum for the proposed technique. The elapsed time for parameter estimation for NLS technique is minimum and much less compared to other two techniques. Extracted parameters of polycrystalline ELDORA-40 PV panel by the proposed technique have been validated through simulation and experimental current-voltage (I-V) and power-voltage (P-V) characteristics.
, Jamal Kharroubi, Arsalane Zarghili
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i6.pp3655-3663

Abstract:
This paper presents a novel speaker modeling approachfor speaker recognition systems. The basic idea of this approach consists of deriving the target speaker model from a personalized background model, composed only of the UBM Gaussian components which are really present in the speech of the target speaker. The motivation behind the derivation of speakers’ models from personalized background models is to exploit the observeddifference insome acoustic-classes between speakers, in order to improve the performance of speaker recognition systems.The proposed approach was evaluatedfor speaker verification task using various amounts of training and testing speech data. The experimental results showed that the proposed approach is efficientin termsof both verification performance and computational cost during the testing phase of the system, compared to the traditional UBM based speaker recognition systems.
Zakariah Yusuf, Norhaliza Abdul Wahab,
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1538-1545; https://doi.org/10.11591/ijece.v7i3.pp1538-1545

Abstract:
This paper presents the development of neural network based model predictive control (NNMPC) for controlling submerged membrane bioreactor (SMBR) filtration process.The main contribution of this paper is the integration of newly developed soft computing optimization technique name as cooperative hybrid particle swarm optimization and gravitational search algorithm (CPSOGSA) with the model predictive control. The CPSOGSA algorithm is used as a real time optimization (RTO) in updating the NNMPC cost function. The developed controller is utilized to control SMBR filtrations permeate flux in preventing flux decline from membrane fouling. The proposed NNMPC is comparedwith proportional integral derivative (PID) controller in term of the percentage overshoot, settling time and integral absolute error (IAE) criteria. The simulation result shows NNMPC perform better control compared with PID controller in term measured control performance of permeate flux.
Madina Hamiane, Fatema Saeed
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i5.pp2555-2564

Abstract:
Magnetic Resonance Imaging is a powerful technique that helps in the diagnosis of various medical conditions. MRI Image pre-processing followed by detection of brain abnormalities, such as brain tumors, are considered in this work. These images are often corrupted by noise from various sources. The Discrete Wavelet Transforms (DWT) with details thresholding is used for efficient noise removal followed by edge detection and threshold segmentation of the denoised images. Segmented image features are then extracted using morphological operations. These features are finally used to train an improved Support Vector Machine classifier that uses a Gausssian radial basis function kernel. The performance of the classifier is evaluated and the results of the classification show that the proposed scheme accurately distinguishes normal brain images from the abnormal ones and benign lesions from malignant tumours. The accuracy of the classification is shown to be 100% which is superior to the results reported in the literature.
Ni Ketut Aryani, Adi Soeprijanto, , Mat Syai’In
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i5.pp2365-2373

Abstract:
Unpredictable increase in power demands will overload the supply subsystems and insufficiently powered systems will suffer from instabilities, in which voltages drop below acceptable levels. Additional power sources are needed to satisfy the demand. Small capacity distributed generators (DGs) serve for this purpose well. One advantage of DGs is that they can be installed close to loads, so as to minimise loses. Optimum placements and sizing of DGs are critical to increase system voltages and to reduce loses. This will finally increase the overall system efficiency. This work exploits Quantum Evolutionary Algorithm (QEA) for the placements and sizing. This optimisation targets the cheapest generation cost. Quantum Evolutionary Algorithm is an Evolutionary Algorithm running on quantum computing, which works based on qubits and states superposition of quantum mechanics. Evolutionary algorithm with qubit representation has a better characteristic of diversity than classical approaches, since it can represent superposition of states.
I. H. Zakaria, M. H. Ahmad, , N. A. Awang, N .A. Ahmad
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1530-1537; https://doi.org/10.11591/ijece.v7i3.pp1530-1537

Abstract:
Trends in the field of nanomaterial-based transformer oil show most of the conducted works have focused only on the transformer oil-based nanofluids but limited studies on the stability of transformer oil-based nanofluids. Since mineral oil-based nanofluids still can produce the sedimentation, thus the cold-atmospheric pressure plasma method is proposed to functionally modify the Silicon Dioxide (SiO2) nanofiller in order to enhance the electrical properties of the mineral oil-based nanofluids. The AC breakdown strength oil samples before and after modification were measured. It was found that the plasma treated nanofluids have higher AC breakdown voltage compared to pure oil and untreated nanofluids. Also, Fourier Transform Infrared (FTIR) Spectroscopy has been used in this study to analyse the physical changes of oil samples. It is envisaged that the added silica nanofiller has significant effect on electrical properties of the transformer oil-based nanofluids which would enable to the development of an improved class of liquid dielectric for the application of power transformer.
I Made Wartana, Ni Putu Agustini, Jai Govind Singh
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i5.pp2329-2337

Abstract:
In recent decades, one of the main management’s concerns of professional engineers is the optimal integration of various types of renewable energy to the grid. This paper discusses the optimal allocation of one type of renewable energy i.e. wind turbine to the grid for enhancing network’s performance. A multi-objective function is used as indexes of the system’s performance, such as increasing system loadability and minimizing the loss of real power transmission line by considering security and stability of systems’ constraints viz.: voltage and line margins, and eigenvalues as well which is representing as small signal stability. To solve the optimization problems, a new method has been developed using a novel variant of the Genetic Algorithm (GA), specifically known as Non-dominated Sorting Genetic Algorithm II (NSGA-II). Whereas the Fuzzy-based mechanism is used to support the decision makers prefer the best compromise solution from the Pareto front. The effectiveness of the developed method has been established on a modified IEEE 14-bus system with wind turbine system, and their simulation results showed that the dynamic performance of the power system can be effectively improved by considering the stability and security of the system.
Nada N. Tawfeeq
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 894-898; https://doi.org/10.11591/ijece.v7i2.pp894-898

Abstract:
Microwave engineers have been known to designedly created defects in the shape of carved out patterns on the ground plane of microstrip circuits and transmission lines for a long time, although their implementations to the antennas are comparatively new. The term Defected Ground Structure (DGS), precisely means a single or finite number of defects. At the beginning, DGS was employed underneath printed feed lines to suppress higher harmonics. Then DGS was directly integrated with antennas to improve the radiation characteristics, gain and to suppress mutual coupling between adjacent elements. Since then, the DGS techniques have been explored extensively and have led to many possible applications in the communication industry. The objective of this paper is to design and investigate microstrip patch antenna that operates at 2.4 GHz for Wireless Local Area Network WLAN IEEE 802.11b/g/n, ,Zigbee, Wireless HART, Bluetooth and several proprietary technologies that operate in the 2.4 GHz band. The design of the proposed antenna involves using partially Defected Ground Structure and circular/cross slots and compare it to the traditional microstrip patch antenna. The results show improvement in both the gain of 3.45 dB and the S11 response of -22.3 dB along with reduction in the overall dimensions of the antenna. As a conclusion, the performance of the antenna has been improved through the incorporation with the DGS and slots structures regarding the S11 response and the gain. The proposed antenna become more compact. Finally, the radiation pattern of proposed antenna has remained directional in spite of adding slots on the ground plane.
Dong Kwan Kim
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 3613-3621; https://doi.org/10.11591/ijece.v7i6.pp3613-3621

Abstract:
Code smell refers to any symptom introduced in design or implementation phases in the source code of a program. Such a code smell can potentially cause deeper and serious problems during software maintenance. The existing approaches to detect bad smells use detection rules or standards using a combination of different object-oriented metrics. Although a variety of software detection tools have been developed, they still have limitations and constraints in their capabilities. In this paper, a code smell detection system is presented with the neural network model that delivers the relationship between bad smells and object-oriented metrics by taking a corpus of Java projects as experimental dataset. The most well-known object-oriented metrics are considered to identify the presence of bad smells. The code smell detection system uses the twenty Java projects which are shared by many users in the GitHub repositories. The dataset of these Java projects is partitioned into mutually exclusive training and test sets. The training dataset is used to learn the network model which will predict smelly classes in this study. The optimized network model will be chosen to be evaluated on the test dataset. The experimental results show when the modelis highly trained with more dataset, the prediction outcomes are improved more and more. In addition, the accuracy of the model increases when it performs with higher epochs and many hidden layers.
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1513-1521; https://doi.org/10.11591/ijece.v7i3.pp1513-1521

Abstract:
In this study, a new, simple and cost-effective impedance detection of yeast cell concentration by using a novel integrated dual microneedle-microfluidic impedance flow cytometry was introduced. The reported method for impedance flow cytometry detection utilizes embedded electrode and probe in the microfluidic device to perform measurement of electrical impedance when a presence of cells at sensing area. Nonetheless, this method requires costly and complicatedly fabrication process of electrode. Furthermore, to reuse the fabricated electrode, it also requires intensive and tedious cleaning process. Due to that, a dual microneedle integrated at the half height of the microchannel for cell detection as well as for electrical measurement was demonstrated. A commercial available Tungsten needle was utilized as a dual microneedle. The microneedle was easy to be removed from the disposable PDMS microchannel and can be reused with the simple cleaning process, such as washed by using ultrasonic cleaning. Although this device was low cost, it preserves the core functionality of the sensor, which is capable of detecting the passing cells at sensing area. Therefore, this device is suitable for low cost medical and food safety screening and testing process in developing countries.
, F. Elmariami, A. Belfqih, J. Boukherouaa
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 2321-2328; https://doi.org/10.11591/ijece.v7i5.pp2321-2328

Abstract:
This paper presents a novel smart local backup protection SLBP used for the support and backup of the protective relays in a smart substation. The proposed SLBP is based on the IEC61850 standards and the concept consists of the acquisition of Generic Object Oriented Substation Event GOOSE used for tripping and interlocks exchange between Intelligent Equipment Devices IEDs and the reading of the Sampled Value SV existing in the process bus coming from Mergin Units MU or Non-Conventional Instrument Transformers NCIT. Several logical schemes to protect different zones of the substation are presented and how can be integrated using data in the substation automation system. The SLBP was developed using an open source library and free operating system. Moreover, a low cost prototype is presented in order to evaluate the efficiency and the operation of the SLBP under diverse scenarios of the proposed logical protective schemes such us breaker failure and overcurrent protection
Woo Wei Kai, Nabihah Binti Ahmad, Mohamad Hairol Bin Jabbar
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 3010-3019; https://doi.org/10.11591/ijece.v7i6.pp3010-3019

Abstract:
The static power consumption is an important parameter concern in IC design due to t for a higher integration numbers of transistor to achieve greater performance in a single chip. Leakage current is the main issues for static power dissipation in standby mode as the size of transistor been scale. Therefore, the subthreshold leakage current rises due to threshold voltage scaling and gate leakage current increases due to scale down of oxide thickness. In this paper, a Variable Body Biasing (VBB) technique was applied to reduce static power consumption in VLSI design. The VBB technique used a DC bias at body terminal to control the threshold voltage efficiently. The Synopsys Custom Designer EDA tools in 90nm MOSFET technology was used to design a 1-bit full adder with VBB technique in full custom methodology. The simulation of 1-bit full adder was carried out with operation voltage supply was compared in conventional technique and VBB technique. The results achieved the reduction in term of peak power, and average power, in static CMOS 1-bit full adder compared with conventional bias and VBB technique.
, Atulya Prasad Naik
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1725-1737; https://doi.org/10.11591/ijece.v7i4.pp1725-1737

Abstract:
This paper presents a new method for transmission loss allocation in a deregulated power system. As the power loss is a nonlinear quantity, so to allocate the loss in a common transmission corrider is a difficult task. It allocates transmission losses to loads based on the actual power flow in the lossy lines due to the concerned load. Each lossy line is subdivided into as many sub-lines as corresponding to the numbers of load attached to it. The tracing of power flow through each sub-line is worked out by using proportional sharing method. The power loss in each lossy line is equal with the total loss due to all the sub-lines under it. Then by using Pro-rata for each lossy line, the individual loss for each sub-line is formulated. As the application of Pro-rata is limited to an individual line of the system, so the error in calculation is minimized. The total loss allocated to a particular load is the sum of losses occurred in each lossy lines through which the power is flowing to the concerned load. As this method is based on the actual flow of power in the transmission line corresponding to the concerned load, hence, the loss allocation made by the method gives proper and justifiable allocations to the different loads which are attached to the system.The proposed method is applied to a six-bus system and finds the mismatch in the commonly used methods. Then, it is applied to higher bus systems in which more accurate results are obtained compared to the other methods.
Fouad Abdulameer Salman, Aziz Bin Deraman,
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i6.pp3632-3642

Abstract:
As consumer demand for user friendly software increases, usability evaluation is crucial to develop software systems which are easy to learn and use. However, implementation of usability evaluation is challenging for small and medium-sized enterprises (SMEs) due to factors such as lack of technical expertise, knowledge and experience of methods and standards. This results in neglect, or poorly executed evaluations of projects, resulting in software that disappoints and frustrates clients. To overcome this loss of competitiveness, we propose here a visual incorporation tool derived from ISO standards that would assist software development teams in SMEs in understanding and implementing usability evaluations. It shows fundamental Usability Engineering (UE) and Software Engineering (SE) activities and artifacts relevant to the usability evaluation and software development process, with potential incorporation points being highlighted. Dependencies and relationships are shown by links between activities and artifacts. Additionally, convergent artifacts of both disciplines were identified and shown. Evaluation of the proposed tool was based on the questionnaire results of software development practitioners from SMEs.
B. A. F. Esmail, , , , M. K. A. Rahim
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 2942-2949; https://doi.org/10.11591/ijece.v7i6.pp2942-2949

Abstract:
In this paper, reconfigurable metamaterial structure at millimeter wave frequency range was designed and simulated for a future fifth generation (5G) mobile-phone beam switching applications. The new proposed structure was composed of a bridge-shaped resonator (BSR) in the front face and strip line at the back face of the unit cell which operates at 28 GHz. First, non-reconfigurable low loss BSR unit cell was designed and subsequently, the reconfigurability was achieved using four switches formed in the gaps of the structure. The proposed structure achieves the lowest loss and almost full transmission among its counterparts by -0.06 dB (0.99 in linear scale). To demonstrate the reconfigurability of the metamaterial, the reflection and transmission coefficients and real parts of the effective refractive index at each reconfigured frequency were studied and investigated. Simulation results showed that a high transmission and reflection peaks occur at each resonance frequency according to change the state of the switches.
Nurul Bahiah Mohd Noor, Mohd Ridzuan Ahmad
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 1506-1512; https://doi.org/10.11591/ijece.v7i3.pp1506-1512

Abstract:
Actuators based on smart materials such as piezoelectric actuators (PEAs) are widely used in many applications to transform electrical signal to mechanical signal and vice versa. However, the major drawbacks for these smart actuators are hysteresis nonlinear, creep and residual vibration. In this paper, PEAs are used for active vibration application. Therefore, a model of PEA must be established to control the vibration that occurs in the system. The frequencies of 1 Hz, 20 Hz and 50 Hz were tested on the PEAs. The results obtained from the experimental were used to develop transfer function model by employing system identification technique. Meanwhile, the model validation was based on level of models fitness to estimation data, mean squared error (MSE), final prediction error (FPE) and correlation test. The experimental result showed that the displacement of the actuator is inversely proportional to the frequency. The following consequences caused the time response criteria at 50 Hz achieved smallest overshoot and fastest response of rise time and settling time.
Sushil Kumar Verma, R.S. Thakur, Shailesh Jaloree
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i4.pp2223-2231

Abstract:
The major intention of higher education institutions is to supply quality education to its students. One approach to get maximum level of quality in higher education system is by discovering knowledge for prediction regarding the internal assessment and end semester examination. The projected work intends to approach this objective by taking the advantage of fuzzy inference technique to classify student scores data according to the level of their performance. In this paper, student’s performance is evaluated using fuzzy association rule mining that describes Prediction of performance of the students at the end of the semester, on the basis of previous database like Attendance, Midsem Marks, Previous semester marks and Previous Academic Records were collected from the student’s previous database, to identify those students which needed individual attention to decrease fail ration and taking suitable action for the next semester examination.
, Israth Jahan Chowdhury, Rafiqul Islam, Nur Aishah Binti Zainal
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i6.pp2970-2976

Abstract:
LoRaWAN is a long-range, low-power, wireless telecommunications method; expected to play a big role for the Internet of Things. End appliances use LoRaWAN through a single wireless hop to communicate with gateways linked to the Internet that function as transparent bridges relaying messages amongst these end-devices and a central network server. This technology youtes a combination of extended range, low power utilization and protected data communication and is gaining significant traction in IoT networks being deployed by wireless network operators. However, no comprehensive evaluation of the technology exists in the open literature. The main intention of this paper is to investigate the effects of shadowing on LoRaWAN links and analyze the performance in terms of packet loss ratio for different physical layer settings. Results indicate large differences in performance when shadowing is taken into consideration upsetting the expected performance tremendously.
Bouhouch Adil, Loqman Chakir, El Qadi Abderrahime
International Journal of Electrical and Computer Engineering (IJECE), Volume 7, pp 3583-3592; https://doi.org/10.11591/ijece.v7i6.pp3583-3592

Abstract:
We describe a new approach to solve the problem to find the maximum independent set in a given Graph, known also as Max-Stable set problem (MSSP). In this paper, we show how Max-Stable problem can be reformulated into a linear problem under quadratic constraints, and then we resolve the QP result by a hybrid approach based Continuous Hopfeild Neural Network (CHN) and Local Search. In a manner that the solution given by the CHN will be the starting point of the local search. The new approach showed a good performance than the original one which executes a suite of CHN runs, at each execution a new leaner constraint is added into the resolved model. To prove the efficiency of our approach, we present some computational experiments of solving random generated problem and typical MSSP instances of real life problem.
Suyoto Suyoto, Iskandar Iskandar, Sugihartono Sugihartono,
International Journal of Electrical and Computer Engineering (IJECE), Volume 7; https://doi.org/10.11591/ijece.v7i2.pp905-911

Abstract:
Conventional timing estimation schemes based on autocorrelation experience performance degradation in the multipath channel environment with high delay spread. To overcome this problem, we proposed an improvement of the timing estimation for the OFDM system based on statistical change of symmetrical correlator. The new method uses iterative normalization technique to the correlator output before the detection based on statistical change of symmetric correlator is applied. Thus, it increases the detection probability and achieves better performance than previously published methods in the multipath environment. Computer simulation shows that our method is very robust in the fading multipath channel
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