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29,939 Article Results

Experimental study of capacity and electrode structure of six cell dynamic lead acid battery

10.12928/telkomnika.v19i4.17845
Kurriawan Budi; Universitas PGRI Kanjuruhan Malang Pranata , Yuni; University of Brawijaya Triasari , Nur; University of Brawijaya Khairati , Istiroyah; University of Brawijaya Istiroyah , Mauludi Ariesto; University of Brawijaya Pamungkas , Muhammad; University of Brawijaya Ghufron
The six cells of the dynamic lead acid battery (DLAB) series have been made to resemble the accumulator with sulfuric acid single electrolyte. The tank was filled with 1200 mL of 30% sulfuric acid and circulated through each unit cell by a minipump during charge-discharge process. Experiments were carried out by providing a charging current of 2A, while the discharge current was varied at 0.5 A, 0.6 A, 0.7 A, 0.8 A for 10 continuous cycle to obtain the battery with the best characteristics. The experimental results show that all batteries have a working voltage of 10.8-14.4 volt. The discharging current is inversely proportional to the discharging duration. The resulting capacity has an efficiency ranging from 80.1-81.1%. DLAB with 0.5 A discharging current shows the best performance based on the length of duration and the average capacity with value of 109.61 h and 6168 mAh while for the ideal performance stability is obtained by DLAB with 0.7 A discharging current. The electrochemical reaction produces angelsite and plattnerite phases on the positive electrode. Meanwhile, angelsite and lead phases are formed on the negative electrode.
Volume: 19
Issue: 4
Page: 1369-1378
Publish at: 2021-08-01

IoT-based air quality monitoring systems for smart cities: A systematic mapping study

10.11591/ijece.v11i4.pp3470-3482
Danny Munera , Diana P. Tobon V. , Johnny Aguirre , Natalia Gaviria Gomez
The increased level of air pollution in big cities has become a major concern for several organizations and authorities because of the risk it represents to human health. In this context, the technology has become a very useful tool in the contamination monitoring and the possible mitigation of its impact. Particularly, there are different proposals using the internet of things (IoT) paradigm that use interconnected sensors in order to measure different pollutants. In this paper, we develop a systematic mapping study defined by a five-step methodology to identify and analyze the research status in terms of IoT-based air pollution monitoring systems for smart cities. The study includes 55 proposals, some of which have been implemented in a real environment. We analyze and compare these proposals in terms of different parameters defined in the mapping and highlight some challenges for air quality monitoring systems implementation into the smart city context.
Volume: 11
Issue: 4
Page: 3470-3482
Publish at: 2021-08-01

Optimization of learning algorithms in multilayer perceptron for sheet resistance of reduced graphene oxide thin-film

10.11591/ijeecs.v23.i2.pp686-693
Noor Aiman bin Aminuddin , Nurlaila Ismail , Marianah Masrie , Siti Aishah Mohamad Badaruddin
Multilayer perceptron (MLP) optimization is carried out to investigate the classifier's performance in discriminating the uniformity of reduced Graphene Oxide(rGO) thin-film sheet resistance. This study used three learning algorithms: resilient back propagation (RP), scaled conjugate gradient (SCG) and levenberg-marquardt (LM). The dataset used in this study is the sheet resistance of rGO thin films obtained from MIMOS Bhd. This work involved samples selection from a uniform and non-uniform rGO thin-film sheet resistance. The input and output data were under going data pre-processing: data normalization, data randomization and data splitting. The data were dividedin to three groups; training,  validation and testing with a ratio of 70%: 15%: 15%, respectively. A varying number of hidden neurons optimized the learning algorithms in MLP from 1 to 10. Their behavior helped establish the best learning algorithms in discriminating MLP for rGO sheet resistance uniformity. The performances measured were the accuracy of training, validation and testing dataset, mean squared errors (MSE) andepochs. All the analytical work in this study was achieved automatically via MATLAB software version R2018a. It was found that the LM is dominant inthe optimization of a learning algorithm in MLP forrGO sheet resistance.The MSE for LM is the most reduced amid SCG and RP. 
Volume: 23
Issue: 2
Page: 686-693
Publish at: 2021-08-01

Text classification model for methamphetamine-related tweets in Southeast Asia using dual data preprocessing techniques

10.11591/ijece.v11i4.pp3617-3628
Narongsak Chayangkoon , Anongnart Srivihok
Methamphetamine addiction is a prominent problem in Southeast Asia. Drug addicts often discuss illegal activities on popular social networking services. These individuals spread messages on social media as a means of both buying and selling drugs online. This paper proposes a model, the “text classification model of methamphetamine tweets in Southeast Asia” (TMTA), to identify whether a tweet from Southeast Asia is related to methamphetamine abuse. The research addresses the weakness of bag of words (BoW) by introducing BoW and Word2Vec feature selection (BWF) techniques. A domain-based feature selection method was performed using the BoW dataset and Word2Vec. The BWF dataset provided a smaller number of features than the BoW and TF–IDF dataset. We experimented with three candidate classifiers: Support vector machine (SVM), decision tree (J48) and naive bayes (NB). We found that the J48 classifier with the BWF dataset provided the best performance for the TMTA in terms of accuracy (0.815), F-measure (0.818), Kappa (0.528), Matthews correlation coefficient (0.529) and high area under the ROC Curve (0.763). Moreover, TMTA provided the lowest runtime (3.480 seconds) using the J48 with the BWF dataset.
Volume: 11
Issue: 4
Page: 3617-3628
Publish at: 2021-08-01

Online 3D path planning for Tri-copter drone using GWO-IBA algorithm

10.12928/telkomnika.v19i4.18697
Sadiq Jawad; University of Baghdad R. , Muna H.; University of Baghdad Saleh
Robots at present are involved in many parts of life, especially mobile robots, which are two parts, ground robots and flying robots, and the best example of a flying robot is the drone. Path planning is a fundamental part of UAVs because the drone follows the path that leads it to goal with obstacle avoidance. Therefore, this paper proposes a hybrid algorithm (grey wolf optimization - intelligent bug algorithm GWO-IBA) to determine the best, shortest and without obstacles path. The hybrid algorithm was implemented and tested in the MATLAB program on the Tri-copter model, and it gave different paths in different environments. The paths obtained were characterized by being free of obstacles and the shortest paths available to reach the target.
Volume: 19
Issue: 4
Page: 1334-1341
Publish at: 2021-08-01

Location tracking using LoRa

10.11591/ijece.v11i4.pp3123-3128
Norlezah Hashim , Fakrulradzi Idris , Tuan Nur Anisa Tuan Ab Aziz , Siti Halma Johari , Rozilawati Mohd Nor , Norfariza Ab Wahab
Local area network (LAN) as Bluetooth, WiFi and ZigBee are well established technology. The biggest problem with many LAN is the battery consumption and short ranges link budgets. LoRa is a new, private, unlicensed and spread spectrum modulation technique which allows sending low rates at extremely long ranges with minimal power consumption. More importantly, there is no access fee associated with this type of wireless technology. The main idea behind this work is to conduct performance and capability analysis of a currently available LoRa transceiver. We develop a location monitoring system using LoRa and global positioning system (GPS) module and we analyze the detectable range of its data, its battery consumption as well as received signal strength indicator (RSSI). Our deployment experiment demonstrates that the system is able to detect the transmitted data within 290 meters of distances. Using 6 volts of battery AA, the transmission of data still occurred after 24 hours. This project is emphasized a location monitoring system that provide low power usage but long range.
Volume: 11
Issue: 4
Page: 3123-3128
Publish at: 2021-08-01

A new hybrid conjugate gradient algorithm for optimization models and its application to regression analysis

10.11591/ijeecs.v23.i2.pp1100-1109
Ibrahim Mohammed Sulaiman , Norsuhaily Abu Bakar , Mustafa Mamat , Basim A. Hassan , Maulana Malik , Alomari Mohammad Ahmed
The hybrid conjugate gradient (CG) method is among the efficient variants of CG method for solving optimization problems. This is due to their low memory requirements and nice convergence properties. In this paper, we present an efficient hybrid CG method for solving unconstrained optimization models and show that the method satisfies the sufficient descent condition. The global convergence prove of the proposed method would be established under inexact line search. Application of the proposed method to the famous statistical regression model describing the global outbreak of the novel COVID-19 is presented. The study parameterized the model using the weekly increase/decrease of recorded cases from December 30, 2019 to March 30, 2020. Preliminary numerical results on some unconstrained optimization problems show that the proposed method is efficient and promising. Furthermore, the proposed method produced a good regression equation for COVID-19 confirmed cases globally.
Volume: 23
Issue: 2
Page: 1100-1109
Publish at: 2021-08-01

Detection of brain stroke in the MRI image using FPGA

10.12928/telkomnika.v19i4.18988
Dheyaa; Northern Technical University Alhelal , Ahmed Khazal; Northern Technical University Younis , Ruaa H. Ali; Northern Technical University Al-Mallah
One of the most important difficulties which doctors face in diagnosing is the analysis and diagnosis of brain stroke in magnetic resonance imaging (MRI) images. Brain stroke is the interruption of blood flow to parts of the brain that causes cell death. To make the diagnosis easier for doctors, many researchers have treated MRI images with some filters by using Matlab program to improve the images and make them more obvious to facilitate diagnosis by doctors. This paper introduces a digital system using hardware concepts to clarify the brain stroke in MRI image. Field programmable gate arrays (FPGA) is used to implement the system which is divided into four phases: preprocessing, adjust image, median filter, and morphological filters alternately. The entire system has been implemented based on Zynq FPGA evaluation board. The design has been tested on two MRI images and the results are compared with the Matlab to determine the efficiency of the proposed system. The proposed hardware system has achieved an overall good accuracy compared to Matlab where it ranged between 90.00% and 99.48%.
Volume: 19
Issue: 4
Page: 1307-1315
Publish at: 2021-08-01

Active voltage balancing strategy of asymmetric stacked multilevel inverter

10.11591/ijeecs.v23.i2.pp665-674
Mostafa Q. Kasim , Raaed F. Hassan
Multilevel inverters (MLI) play an important role in AC applications and are undergoing continuous development in topology and control. In higher levels inverters, conventional MLIs have high components count which calls for modification of these topologies to obtain the same number of levels with fewer components to reduce cost and size. Balancing of the capacitors voltages is crucial for the operation of the MLI and it becomes more challenging in higher levels. This paper presents an active voltage balancing strategy for a reduced switch count five-leve topology which is the asymmetric stacked multilevel inverter (ASMLI). The ASMLI uses fewer components than the conventional MLIs when used in their five-levelconfiguration. The proposed active voltage balancing strategy uses simple measurements and logic to assure a balanced capacitors voltages during steady state and transients. The performance was examined and compared based on two modulation techniques with LCL filter and RL load using MATLAB/Simulink. The results show that the active voltage balancing strategy can trace all capacitors voltages to the reference value simultaneously with less than 1% voltage error, fast dynamic response, and an acceptable total harmonic distortion (THD) which allows the proposed setup to be an available option for medium voltage applications. 
Volume: 23
Issue: 2
Page: 665-674
Publish at: 2021-08-01

High efficiency Doherty power amplifier based on asymmetrical matching network

10.11591/ijeecs.v23.i2.pp910-917
Mussa Mabrok , Zahriladha Zakaria , Tole Sutikno
Doherty power amplifier (DPA) with high efficiency at the output power back off is highly demanded for modern wireless communication systems to achieve high data rates and reduce the power consumption and operation costs. This paper presents a new design strategy for enhancing DPA’s back-off efficiency. New design strategy called asymmetrical matching network is used to achieve asymmetric operation, which helps to compensate for the low power delivered by the peaking stage in the conventional DPA. The simulation results showed an enhancement in the back-off efficiency, where the proposed design is able toachieve 46-52% drain efficiency at 8 dB output power back-off while maintains high efficiency of 73-80 % at saturation over the designed bandwidth of 3.4-3.6 GHz. The proposed design is suitable for high efficiency sub-6 GHz fifth-generation wireless applications. 
Volume: 23
Issue: 2
Page: 910-917
Publish at: 2021-08-01

The impact of sentiment analysis from user on Facebook to enhanced the service quality

10.11591/ijece.v11i4.pp3424-3433
Daniel D. Albesta , Michael L. Jonathan , Muhammad Jawad , Oktovianus Hardiawan , Derwin Suhartono
Facebook's influence on the modern social media platform is undoubtedly enormous. While it has gotten a backlash for its inability to control its influence over important affairs, there are still many questions regarding people's perception of Facebook and their sentiment over Facebook. This paper's role in this ongoing debate is to give a glimpse of people's sentiment and perception of Facebook in recent times. By collecting samples data from Facebook's Top Page, this paper hopes to represent a significant amount of people's aspirations towards this company. By processing the data with a processing tool to construct and model out the data and a sentiment analyzer tool helps determine the sentiment, this paper can deduce a 600-comment worth of processed data. The results from the 600 sampled comments concluded that the sentiments towards Facebook are 41.50% negative comments, 22.83% neutral comments, and 35.67% positive comments.
Volume: 11
Issue: 4
Page: 3424-3433
Publish at: 2021-08-01

Analysis of hybrid non-linear autoregressive neural network and local smoothing technique for bandwidth slice forecast

10.12928/telkomnika.v19i4.17024
Mohamed Khalafalla; University Technology Malaysia Hassan , Sharifah H. S.; University Technology Malaysia Ariffin , Sharifah Kamilah Syed-; University Technology Malaysia Yusof , N. Effiyana; University Technology Malaysia Ghazali , Mohamed EA; Future University Kanona
The demand for high steady state network traffic utilization is growing exponentially. Therefore, traffic forecasting has become essential for powering greedy application and services such as the internet of things (IoT) and Big data for 5G networks for better resource planning, allocation, and optimization. The accuracy of forecasting modeling has become crucial for fundamental network operations such as routing management, congestion management, and to guarantee quality of service overall. In this paper, a hybrid network forecast model was analyzed; the model combines a non-linear auto regressive neural network (NARNN) and various smoothing techniques, namely, local regression (LOESS), moving average, locally weighted scatterplot smoothing (LOWESS), the Sgolay filter, Robyn loess (RLOESS), and robust locally weighted scatterplot smoothing (RLOWESS). The effects of applying smoothing techniques with varied smoothing windows were shown and the performance of the hybrid NARNN and smoothing techniques discussed. The results show that the hybrid model can effectively be used to enhance forecasting performance in terms of forecasting accuracy, with the assistance of the smoothing techniques, which minimized data losses. In this work, root mean square error (RMSE) is used as performance measures and the results were verified via statistical significance tests.
Volume: 19
Issue: 4
Page: 1078-1089
Publish at: 2021-08-01

Effect of random sampling on spectrum sensing for cognitive radio networks

10.12928/telkomnika.v19i4.20399
Asmaa; Cadi Ayyad University Maali , Hayat; Cadi Ayyad University Semlali , Sara; Cadi Ayyad University Laafar , Najib; Cadi Ayyad University Boumaaz , Abdallah; Cadi Ayyad University Soulmani
Cognitive radio is a mechanism allowing dynamic access to spectrum channels. Since its beginnings, researchers have been working on using this inventive technology to control and manage the spectrum resources. Consequently, this research field has been progressing rapidly and important advances have been made. Spectrum sensing is a key function of cognitive radios that helps prevent the harmful interference with licensed users, as well as identifies the available spectrum to improve its utilization. Several spectrum sensing techniques are found in scientific literature. In this paper, we investigate the effect of the random sampling in spectrum sensing. We propose a spectrum sensing approach based on the energy detection and on the maximum eigenvalue detection (MED) combined with random sampling. The performance of the proposed approach is evaluated in terms of the receiver operating characteristics curves and in terms of the detection probability for different values of signal to noise ratio. The obtained results are compared to the uniform sampling case to show the added value of random sampling.
Volume: 19
Issue: 4
Page: 1137-1144
Publish at: 2021-08-01

14-bit ADC as voltage monitoring device for power supply module 6 using I2C interface

10.11591/ijeecs.v23.i2.pp709-716
Edison R. Castillo , Catherine D. Samson , Glenn N. Ortiz , Mark Joseph B. Enojas
Thereare recorded downtime in the current testing processes of microelectronic packages. The available test equipment, the isolation of the power supply modules and the processes of testing must be changed in order to minimize the downtime. This study presents the design and development of a voltage monitoring device made of a 14-bit analog to digital converter (ADC) interfaced through inter-integrated circuit (I2C) for power supply module 6 (PS6). It is built to address the downtime in isolation and testing process of PS6. This setup is able to monitor and display three output voltages operating in 4-12V signals through athin film transistor (TFT) monitor. Tests were conducted for the nominal voltage and current setting scalled the three-point tests. In result, the fault detection and calibration process of PS6 are able to minimize downtimes. The developed voltage monitoring device has an acceptable percentage of 0.04572% which also canbe a replacement for digital multimeters (DMMs) for specific applications to PS6.
Volume: 23
Issue: 2
Page: 709-716
Publish at: 2021-08-01

Reactive power sharing in microgrid using virtual voltage

10.11591/ijece.v11i4.pp2743-2751
Eder A. Molina-Viloria , John E. Candelo Becerra , Fredy E. Hoyos Velasco
The traditional droop control strategy has been applied previously in microgrids (MGs) to share accurately the active power. However, in some cases the result obtained when sharing reactive power is not the best, because of the parameters related to the distances from distributed generators (DGs) to the loads and the power variations. Therefore, this paper proposes a reactive power control strategy for a low voltage MG, where the unequal impedance related to the distances between generators and loads requires adjustments to work with the conventional frequency and voltage droop methods. Thus, an additional coefficient is calculated from parameters of the network that relate the location of elements. The test is perfomed by simulations in the MATLAB-Simulink software, considering a three-node MG with three DGs and a load that can change power at different periods of time. The results show that it is possible to improve reactive power sharing between the DGs located in the MG according to the load changes simulated and to improve voltages with this method.
Volume: 11
Issue: 4
Page: 2743-2751
Publish at: 2021-08-01
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