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29,734 Article Results

Correlation between Reflection Coefficient, Dielectric Properties and Brix Level of Malaysian Oranges at Microwave Frequencies

10.11591/ijeecs.v10.i3.pp853-858
Rafidah Rosman , Mohamad Ngasri Dimon , You Kok Yeow
This paper presents sweetness degree (°Brix) prediction of the Malaysian oranges using microwave technique. Experimental measurement using monopole sensor and reflectometer was done in order to correlate the relationship between measured reflection coefficient, S11  of the orange and its sweetness level. Up to fifty orange samples were freshly plucked from local grower’s farm and tested. The unique design of the monopole sensor’s holder is made of nylon. The experiment test bed was set up based on the standard dimension of monopole sensor available in the market. The operating frequency is focusing on 2.2 GHz as it shows significant sensitivity for determining Malaysian local oranges sweetness level.
Volume: 10
Issue: 3
Page: 853-858
Publish at: 2018-06-01

PAPR Reduction Techniques in Generalized Inverse Discrete Fourier Transform Non-Orthogonal Frequency Division Multiplexing System

10.11591/ijeecs.v10.i3.pp1045-1052
Iram Maisarah Mokhtar , Norulhusna Ahmad , Hazilah Mad Kaidi , Mohd Azri Mohd Izhar , Norliza Mohamed
A promising system of Generalized Inverse Discrete Fourier Transform Non-Orthogonal Frequency Division Multiplexing (GIDFT n-OFDM) system can fulfil the requirement of supporting higher data rate in Fifth Generation (5G) technology. However, this system experience High Peak to Average Power Ratio (PAPR) due to massive number of subcarriers signal is transmitted. In this paper, three types of usual PAPR reduction techniques were applied in GIDFT n-OFDM system which are Clipping, Partial transmit Transform (PTS) and Selective Mapping (SLM). The system performance is compared and evaluated using Complementary Cumulative Distribution Function (CCDF) plot. Simulation results show that SLM technique give significant reduction of PAPR 9 dB of the original performance.
Volume: 10
Issue: 3
Page: 1045-1052
Publish at: 2018-06-01

A Mixed Method Research on Peer Assessment

10.11591/ijere.v7i2.12770
Gokhan Izgar , Ahmet Oguz Akturk
The purpose of this study is to investigate the relationship between peer assessment and instructor assessment and make a comparison with views of preservice teachers. Since qualitative and quantitative methods were used together in the study, it was grounded on the mixed method approach. The quantitative data in this study, in which 27 preservice teachers participated on a voluntary basis, were obtained from scoring rubric whereas qualitative data were obtained from a semi-structured interview form prepared by the researchers. Statistical analyses were conducted to analyze the quantitative data collected within the scope of the study, whereas Pearson Product-Moment Correlation Coefficient was used to analyze the relationship between instructor assessment and peer assessment, and paired samples t test was used to determine the differences between pairwise groups. The qualitative data, on the other hand, were analyzed using the content analysis technique. As a result of the analysis, it was seen that there was a positive and significant correlation between instructor assessment and peer assessment. When the preservice teachers’ views were examined, those views rose to prominence stating that making assessments contributed to learning; they grew aware of imperfect knowledge; questioning and critical thinking improved, and fair assessment skills developed. This was interpreted to mean that preservice teachers could distinguish between adequate and inadequate work. However, when the preservice teachers’ views concerning their assessments by their peers were examined, the view attracted attention stating that friendship relations and personal problems affected assessment negatively and therefore peers gave low scores. At this point, when the mean scores were examined, it was seen that mean peer scores were higher than instructor mean scores. This was interpreted to mean that some preservice teachers did not have confidence in their peers.
Volume: 7
Issue: 2
Page: 118–126
Publish at: 2018-06-01

Finite-Control-Set Predictive Current Control Based Real and Reactive Power Control of Grid-Connected Hybrid Modular Multilevel Converter

10.11591/ijpeds.v9.i2.pp660-667
Rashmi Ranjan Behera , Amarnath Thakur
This paper proposes the grid application of modified three-phase topology of Modular Multilevel Converter (MMC) using finite-control-set predictive control. This topology has reduced number of switch counts compared to the conventional MMC, eliminates the problem of circulating current and having higher efficiency. A single dc source is required to produce sinusoidal outputs. The number of sub-modules (SMs) in this topology is half of the SMs required in case of MMC, in addition to a single H-bride circuit per phase. The finite-control-set predictive current control scheme for the grid connected dc source through the Hybrid Modular Multilevel Converter (HMMC). This controller controls the desired real and reactive power demand of the grid instantaneously. The simulation study of a three phase grid connected system has been done in Matlab/Simulink and the results are provided for the different real and reactive power demands, to validate the concepts.
Volume: 9
Issue: 2
Page: 660-667
Publish at: 2018-06-01

Extended Bandwidth Optimized and Energy Efficient Dynamic Source Routing Protocol in Mobile Ad-hoc Networks

10.11591/ijece.v8i3.pp1460-1466
Bindiya Bhatia , M. K. Soni , Parul Tomar
With the increase in the evolution of wireless communication, the ad-hoc networks are gaining attention and are significantly becoming the technology solutions to the various problems. Mobile ad-hoc Networks (MANETs) are envisaged to grow as a main component in the today 4G architecture, and ad hoc networks are projected to be a significant element of the whole future wireless communication. The MANETs are infrastructure less, self-forming and self-organizing network in which there is no control of any centralized entity. The nodes are free to move around the network with dynamic topology. But this self formation, flexibility and scalability create many challenges and design constraints like hidden  terminal, limited bandwidth, limited energy of a node, unpredictable change in the topology etc. Bandwidth and energy are the scarce resources of the network. In order to effectively manage the consumption of bandwidth and energy, an algorithm is proposed which is the extension of traditional Dynamic Source Routing (DSR) reactive routing protocol. The extended protocol applies the mobile agents to carry the data. The proposed work is intended to optimize the bandwidth and making the protocol energy efficient.
Volume: 8
Issue: 3
Page: 1460-1466
Publish at: 2018-06-01

Elementary School Third Grade Students’ Expectations of Their Teachers in The Course of Language Education

10.11591/ijere.v7i2.13452
Sabri Sidekli , Zeliha Cura , Alper Yorulmaz
The purpose of the study is to determine the elementary school third grade students’ expectations of their classroom teachers within the context of the course of language education. The sampling of the study is comprised of 200 elementary school third grade students attending elementary schools in the Milas Province of the city of Muğla. The data were gathered by means of the questionnaire, which had six sub-categories, in order to identify students’ expectations of their teachers. The findings of the study revealed that the students have high expectations of their teachers in terms of the sub-dimensions of active participation, verbal participation, written participation, participating in reading, inclusion of the topics and measurement and evaluation. The students’ expectations of their teachers in relation to the sub-dimension of measurement and evaluation were found to be varying significantly depending on the gender variable. This difference is in favor of boys.
Volume: 7
Issue: 2
Page: 159-166
Publish at: 2018-06-01

Nonlinear Adaptive Control for Wind Turbine Under Wind Speed Variation

10.11591/ijra.v7i2.pp87-95
Abdelhaq.Amar bensaber , Mustapha Benghanem , Mohammed.Amar bensaber , Abdelmadjid. Guerouad
Wind turbines components work as nonlinear systems where electromechanical parameters change frequently [1], which makes nonlinear control an interesting solution to prevail good efficiency. SMC has been largely used in electrical power applications because it offers interesting features like robustness to parametric uncertainties and external disturbances, to conquer the biggest drawback of the SMC, adaptation strategy consists on updating the sliding gain and the turbine torque to contribute with some important characteristics such as chatter-free performance, heftiness, robustness and secure power system operation. Matlab tests are introduced and compared.
Volume: 7
Issue: 2
Page: 87-95
Publish at: 2018-06-01

Determination of Secondary School 4th Grade Students’ Mental Models of the Astronomer

10.11591/ijere.v7i2.11371
Meryem Görecek Baybars , Büşra Tuğçe Kayabas
Teaching astronomy to young generations is of great importance because astronomy education helps us to better understand the world we are living in and to find answers to our questions. In this regard, the current study aimed to determine the secondary school 4th grade students’ mental models of the astronomer. The current research is designed as a descriptive study employing the special case study method. The study was conducted in a city located in the western part of Turkey. The study group is comprised of a total of 77 secondary school 4th grade students attending a state school. In line with the purpose of the study, a data collection tool consisted of 2 open-ended questions was developed. In light of the findings of the study, it can be argued that the mental models possessed by the students about the astronomer are the scientific model, the astronaut model and the celestial bodies model
Volume: 7
Issue: 2
Page: 94–99
Publish at: 2018-06-01

Grid and Force Based Sensor Deployment Methods in Wireless Sensor Network using Particle Swarm Optimization

10.11591/ijeecs.v10.i3.pp1287-1295
Aparna Pradeep Laturkar , Sridharan Bhavani , DeepaliParag Adhyapak
Wireless Sensor Network (WSN) is emergingtechnology and has wide range of applications, such as environment monitoring, industrial automation and numerous military applications. Hence, WSN is popular among researchers. WSN has several constraints such as restricted sensing range, communication range and limited battery capacity. These limitations bring issues such as coverage, connectivity, network lifetime and scheduling & data aggregation. There are mainly three strategies for solving coverage problems namely; force, grid and computational geometry based. PSO is a multidimensional optimization method inspired from the social behavior of birds called flocking. Basic version of PSO has the drawback of sometimes getting trapped in local optima as particles learn from each other and past solutions. This issue is solved by discrete version of PSO known as Modified Discrete Binary PSO (MDBPSO) as it uses probabilistic approach. This paper discusses performance analysis of random; grid based MDBPSO (Modified Discrete Binary Particle Swarm Optimization), Force Based VFCPSO and Combination of Grid & Force Based sensor deployment algorithms based on interval and packet size. From the results of Combination of Grid & Force Based sensor deployment algorithm, it can be concluded that its performance is best for all parameters as compared to rest of the three methods when interval and packet size is varied.
Volume: 10
Issue: 3
Page: 1287-1295
Publish at: 2018-06-01

Design of Robust Fractional-Order PID Controller for DC Motor Using the Adjustable Performance Weights in the Weighted-Mixed Sensitivity Problem

10.11591/ijra.v7i2.pp108-118
Toufik Amieur , Moussa Sedraoui , Oualid Amieur
This paper deals with the robust series and parallel fractional-order PID synthesis controllers with the automatic selection of the adjustable performance weights, which are given in the weighted-mixed sensitivity problem. The significant contribution of the paper is to achieve the good trade-off between nominal performances and robust stability for DC motor regardless its nonlinear dynamic behavior, the unstructured model uncertainties and the effect of the sensor noises on the feedback control system. The main goal is formulated as the weighted-mixed sensitivity problem with unknown adjustable performance weight.  This problem is then solved using an adequate optimization algorithm and its optimal solution leads to determine simultaneously the robust fractional PID controller, which is proposed by the series and the parallel fractional structures, As well as, the obtained optimal solution determines the corresponding adjustable performance weight. The proposed control technique is applied on DC motor where its dynamic behavior is modeled by unstructured multiplicative model uncertainty. The obtained performances are compared in frequency- and time-domains with those given by both integer controllers such classical PID and H∞ controllers.
Volume: 7
Issue: 2
Page: 108-118
Publish at: 2018-06-01

Exponential Reaching Law and Sensorless DTC IM Control with Neural Network Online Parameters Estimation based on MRAS

10.11591/ijra.v7i2.pp77-86
Legrioui Said , Rezgui Salah Eddine , Benalla Hocine
The most important problem in the control of induction machine (IM) is the change of its parameters, especially the stator resistance and rotor-time constant. The objective of this paper is to implement a new strategy in sensorless direct torque control (DTC) of an IM drive. The rotor flux based model reference adaptive system (MRAS) is used to estimate conjointly the rotor speed, the stator resistance and the inverse rotor time constant, the process of the estimation is performed on-line by a new MRAS-based artificial neural network (ANN) technique. Furthermore, the drive is complemented with a new exponential reaching law (ERL), based on the sliding mode control (SMC) to significantly improve the performances of the system control compared to the conventional SMC which is known to be susceptible to the annoying chattering phenomenon. An experimental investigation was carried out via the Matlab/Simulink with real time interface (RTI) and dSPACE (DS1104) board where the behavior of the proposed method was tested at different points of IM operation.
Volume: 7
Issue: 2
Page: 77-86
Publish at: 2018-06-01

A Survey on Cleaning Dirty Data Using Machine Learning Paradigm for Big Data Analytics

10.11591/ijeecs.v10.i3.pp1234-1243
Jesmeen M. Z. H , J. Hossen , S. Sayeed , CK Ho , Tawsif K , Armanur Rahman , E.M.H. Arif
Recently Big Data has become one of the important new factors in the business field. This needs to have strategies to manage large volumes of structured, unstructured and semi-structured data. It’s challenging to analyze such large scale of data to extract data meaning and handling uncertain outcomes. Almost all big data sets are dirty, i.e. the set may contain inaccuracies, missing data, miscoding and other issues that influence the strength of big data analytics. One of the biggest challenges in big data analytics is to discover and repair dirty data; failure to do this can lead to inaccurate analytics and unpredictable conclusions. Data cleaning is an essential part of managing and analyzing data. In this survey paper, data quality troubles which may occur in big data processing to understand clearly why an organization requires data cleaning are examined, followed by data quality criteria (dimensions used to indicate data quality). Then, cleaning tools available in market are summarized. Also challenges faced in cleaning big data due to nature of data are discussed. Machine learning algorithms can be used to analyze data and make predictions and finally clean data automatically.
Volume: 10
Issue: 3
Page: 1234-1243
Publish at: 2018-06-01

Anxiety in Visually Impaired Students about the Future

10.11591/ijere.v7i2.13263
Aydın Kızılaslan , M. Meral Kızılaslan
The aim of this study is to determine the anxiety level that visually impaired students may have for the future when planning their profession. Anxiety is defined as excessive level fear and worry about real or imaginary situations. So the excessive worry can affect the ability to act to solve a problem. This study is a case study based on the semi-structured interviews. The study group consists of six 8th grade students with visual impairment. The aim of selecting students with visual impairment as a sample group is to determine the individuals who are aware that education is an important for their future plans but at the same time aware that the barriers created by society have greater impact on their the socialization. As a result, visually impaired individuals are willing to be part of the society, but the created obstacles cause anxiety in many different ways as they constitute their futures. This situation negatively affects their motivation and academic performance, and diminishes the importance of education for them as well.
Volume: 7
Issue: 2
Page: 152–158
Publish at: 2018-06-01

Comparative Study Entered New Approach FMV and Control SFR for Active Compensation of Harmonic Currents in Shunt Active Power Filter

10.11591/ijra.v7i2.pp119-128
Loutfi Benyettou
In this article, we discuss the problem of degradation of current in electrical installations, which follows directly from the proliferation of non-linear loads, to solve it, we used a two-level inverter as a parallel active filter, which injects current harmonics at the connection point with two compensation methods the method of instantaneous active and reactive power (pq method and pq method with MVF) method binds to the repository synchronization. We will highlight two control strategies by hysteresis and PWM. Simulation results using Blok set Power System (PBS)/ Simulink Matlab show reduced THD in accordance with standard IEEE-519.
Volume: 7
Issue: 2
Page: 119-128
Publish at: 2018-06-01

Application of Sliding Mode Control Technique to Regulate DC/DC Boost Converters in Systems Exploiting Photovoltaic Power Generation

10.11591/ijra.v7i2.pp96-107
Le Tien Phong , Ngo Duc Minh
This paper introduces a new method, called IB-SMC method, to control DC/DC boost converters in systems exploiting photovoltaic power generation. This method combines the sliding mode control technique and iterative-bisectional  technique in the maximum power point tracker to change operations modes of photovoltaic power generation. The IB-SMC controller uses voltage sliding surface to evaluate the relation of instantaneous voltage at the input converter and instantaneous voltage at the maximum power point. Using information about the power of electromagnetic radiation from a pyranometer and temperature from a temperature sensor, the sliding surface and hyteresis band are changed by practically operational conditions that help improving energy efficiency of the process exploiting PVg. Simulations are carried out by Matlab/Simulink that show the ability to ensure dynamic stability by tracking instaneous maximum power point at any time whenever having any change of the operational condition, static stability by maintaining the operation point at maximum power point whenever not have any change of the operational condition and help to bring out approximately absolute energy efficiency.
Volume: 7
Issue: 2
Page: 96-107
Publish at: 2018-06-01
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