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29,939 Article Results

Teacher evaluation by different internal evaluators: Head of departments, teachers themselves, peers and students

10.11591/ijere.v10i2.20838
Talal S. Almutairi , Nawaf S. Shraid
This study analyzed teacher evaluation in school, through involving different internal evaluators, in order to determine the extent to which they evaluate teacher performance accurately and objectively. Evaluation survey instruments are used in this study, which are designed based the criteria of existing teacher evaluation system in the context, along with other criteria for evaluating teachers. The sample of this study included teachers, heads of departments and students from high schools in four different districts in Kuwait, received responses as 100 from heads of department, 100 from teachers ‘self-evaluation’, 100 from peer and 912 from students. The findings show that there is no significant difference between teachers’ self-evaluation and heads of departments’ evaluation. On the other hand, this study finds that subjectivism and competition may have an effect on peer evaluation and students may over-evaluate their teachers’ performance as attempt to draw a better picture of their teachers in front of evaluators.
Volume: 10
Issue: 2
Page: 588-596
Publish at: 2021-06-01

Protecting Android based applications from malware affected through SMS messages

10.11591/ijeecs.v22.i3.pp1580-1589
J. Sasi Bhanu , J. K. R. Sastry , T. Chandrasekhara Reddy
Users use Android-based applications for communicating through emailing, text messaging, and transmission of audio and video objects. The attackers manipulate the email, text, videos, or audio so that users' receipt of the messages causes malware through their handheld devices. A runtime routine is invoked, which causes damage to the local resources of the mobile phone. The manipulation of the messages is done using different signatures, making it difficult to recognize the same using a single approach. Multiple approaches are sometimes required to detect different signature-based incoming messages. Choosing a method that suits the signature of the incoming message is the key. Malware can also enter at the time of installing third-party apps, clicking on the links provided in the messages, installing and invoking the malware in the background. Many issues are involved in dealing with malware detecting, prevention, and curing. A comprehensive architecture is required to deal with every aspect of dealing malware. In this paper, a comprehensive architecture is presented that considers malware's issue, especially concerning malware affected through short message service (SMS) messages operated under the Android operating system. The disection of the SMS messages have been implemented and 99% accuracy has been achieved.
Volume: 22
Issue: 3
Page: 1580-1589
Publish at: 2021-06-01

Variable reluctance synchronous machines in saturated mode

10.11591/ijpeds.v12.i2.pp662-673
Hleli Hanene , Flah Aymen , Tounsi Souhir
Electric vehicle seems largely based on electrical machines. Finding the best motor type seems be important for having more performances and a transport system robustness. In this work, we present an analytical model of the synchronous machine with variable reluctances in linear and saturated modes. The angular position of the rotor (θ) and the phase current (i) will beused as parameters. The analytical model of this machine will allow us to determinate its magnetic characteristics such inductors, magnetic flux and electromagnetic torque. The results obtained by the analytical model are compared with those obtained by the finite element method. So, basing on Matlab/Simulink tool and by working with finite element method, these results are depicted and the paper objective is illustrated.
Volume: 12
Issue: 2
Page: 662-673
Publish at: 2021-06-01

A method to convert non-numeric characters into numerical values in dynamic time warping for string matching

10.11591/ijece.v11i3.pp2660-2665
Hyun Jun Park
Dynamic time warping (DTW) is one of the well-known algorithms for measuring similarity between two temporal sequences, and it can be used for character matching. It uses a distance of two character strings. However, since the characters are non-numeric, it must be assigned to numerical values to calculate a distance between two character strings. Therefore, in this paper, we propose a method to convert non-numeric characters into numerical values in dynamic time warping for string matching. The proposed method uses normalized correlation coefficient, and it makes DTW gives more accurate results. Experimental results show that the proposed method gives excellent results.
Volume: 11
Issue: 3
Page: 2660-2665
Publish at: 2021-06-01

A regenerative braking energy recuperation from elevator operation in building by active rectifier

10.11591/ijpeds.v12.i2.pp811-821
An Thi Hoai Thu Anh , Luong Huynh Duc
Elevators- means of vertical transportation to carry people and goods are an indispensable part in offices, high-rise buildings, hospitals, commercial areas, hotels, car-parks when blooming urbanization develops worldwide. However, the level of energy consumption in elevator operation is significant, so energy saving solutions have been outlined and applied in practice. With frequent braking phases, regenerative braking energy is wasted on braking resistors. Therefore, this paper proposes regenerative braking energy recuperation method for elevator operation in building by active rectifiers enabling the braking energy to be fed back into utility grid. Simulation results conducted by MATLAB with data collected from OCT5B building-RESCO new urban area, Ha noi, Vietnam have verified saving energy of using active rectifiers replacing diode rectifiers up to 33%.
Volume: 12
Issue: 2
Page: 811-821
Publish at: 2021-06-01

Comparison between butterfly optimization algorithm and particle swarm optimization for tuning cascade PID control system of PMDC motor

10.11591/ijpeds.v12.i2.pp736-744
Kareem G. Abdulhussein , Naseer M. Yasin , Ihsan J. Hasan
In this paper, two optimization methods are used to adjust the gain values for the cascade PID controller. These algorithms are the butterfly optimization algorithm (BOA), which is a modern method based on tracking the movement of butterflies to the scent of a fragrance to reach the best position and the second method is particle swarm optimization (PSO). The PID controllers in this system are used to control the position, velocity, and current of a permanent magnet DC motor (PMDC) with an accurate tracking trajectory to reach the desired position. The simulation results using the Matlab environment showed that the butterfly optimization algorithm is better than the particle swarming optimization (PSO) in terms of performance and overshoot or any deviation in tracking the path to reach the desired position. While an overshoot of 2.557% was observed when using the PSO algorithm, and a position deviation of 7.82 degrees was observed from the reference position.
Volume: 12
Issue: 2
Page: 736-744
Publish at: 2021-06-01

Fire-fighting UAV with shooting mechanism of fire extinguishing ball for smart city

10.11591/ijeecs.v22.i3.pp1320-1326
Nastaran Reza Nazar Zadeh , Ameralden H. Abdulwakil , Mike Joshua R. Amar , Bernadette Durante , Christian Vincent Nico Reblando Santos
With the growth of technology and massive city development, firefighting services have become more challenging to cope with a smart-city concept. One of the challenges that firefighters are facing is reaching the top floors of high-raised buildings. Firefighters need heavy and oversized pieces of equipment to reach top floors, which they sometimes fail to deliver on time due to big cities' traffic. The proposed solution to this global problem is using firefighting unmanned aerial vehicle (UAV) to reach the top floors fast and efficiently; It can also provide a better vision for the firefighting team and slow down the spread of fire using fire extinguishing ball. In this paper, a noble design for a Firefighting UAV with shooting and dropping mechanism of fire extinguishing ball has been developed and successfully tested. A Camera with night vision has been integrated into the UAV to provide a helpful aid for firefighters. The UAV has a controller with a 2.4 GHz radio frequency (RF) signal and video surveillance to regulate the UAV's movement. The controller is also for activating the shooting and dropping mechanism. The researchers examined the behavior of the drone in terms of its stability and functionality.
Volume: 22
Issue: 3
Page: 1320-1326
Publish at: 2021-06-01

Optimization of double stator PMSM with different slot number in inner and outer stators using genetic algorithm

10.11591/ijpeds.v12.i2.pp726-735
Mohd Saufi Ahmad , Dahaman Ishak , Tiang Tow Leong , Mohd Rezal Mohamed
This paper describes the performance enhancement of double stator permanent magnet synchronous machines (DS-PMSM) based on genetic algorithm optimization (GAO). Generally, throughout the development stage, an analytical calculation is implemented to build the initial model of the DS-PMSM since the analytical calculation can provide the initial parameters based on the types and materials used in the machine design. For further improvement, GAO might potentially be applied to provide the optimization technique in searching the optimal motor parameters iteratively and intelligently with specific objective functions. For this aim, a three-phase, DS-PMSM with different number of slots between the outer and inner stators is first designed by using analytical parameter estimation and then later optimized by GAO. The outer and inner stators have 12-slots and 9-slots respectively, while, the rotor carries 10 magnetic poles. Four main input motor parameters, i.e. outer stator slot opening, outer magnet pole arc, inner stator slot opening and inner magnet pole arc are varied and optimized to achieve the design objective functions, i.e. high output torque, low torque ripple, low cogging torque and low total harmonic distortion (THDv). The results from the optimized GAO are compared with the initial motor model and further validated by finite element method (FEM). The results show a good agreement between GAO and FEM. GAO has achieved very significant improvements in enhancing the machine performance.
Volume: 12
Issue: 2
Page: 726-735
Publish at: 2021-06-01

Bigradient neural network-based quantum particle swarm optimization for blind source separation

10.11591/ijai.v10.i2.pp355-364
Hussein M. Salman , Ali Kadhum M. Al-Qurabat , Abd Alnasir Riyadh Finjan
An independent component analysis (ICA) is one of the solutions of a blind source separation problem. ICA is a statistical approach that depends on the statistical properties of the mixed signals. The purpose of the ICA method is to demix the mixed source signals (observation signals) and rcovering those signals. The abbreviation of the problem is that the ICA needs for optimizing by using one of the optimization approaches as swarm intelligent, neural neworks, and genetic algorithms. This paper presents a hybrid method to optimize the ICA method by using the quantum particle swarm optimization method (QPSO) to optimize the Bigradient neural network method that applies to separate mixed signals and recover sources signals. The results of an implement this work prove that this method gave good results comparing with other methods such as the Bigradient neural network and the QPSO method, based on several evaluation measures as signal-to-noise ratio, signal-to-distortion ratio, absolute value correlation coefficient, and the computation time.
Volume: 10
Issue: 2
Page: 355-364
Publish at: 2021-06-01

An internet of things based smart waste system

10.11591/ijece.v11i3.pp2577-2585
Ali M. Jasim , H. H. Qasim , Ethar Habeeb Jasem , Raed Hasan Saihood
The importance of preserving the environment from waste and its pollution lies in many matters such as preserving people health, enhancing the aesthetic character of cites, attracting tourists, and protecting society from environmental disasters. The environmental wastes are the main dilemmas in our daily life and in the world at large. With the existence of modern technology, development and the field of the internet, many solutions have been undertaken to get rid these dilemmas. In this paper, a smart waste system based on internet of things (IoT) technique has been proposed using ESP-32 Wi-Fi microcontroller. This system can be adopted to avoid the accumulation of waste in the streets that distort the face of civilization, also to reduce the burden of workers and limit the workforce. The system is based on a multiple sensors in the garbage baskets, as they measure the waste level by using ultrasonic sensor, the moisture percent and temperature degree using DHT-22 sensor. The sensors data are processed by ESP32 microcontroller and displayed to both LCD screen using I2C protocol and mobile application using IoT cloud. System baskets automatically open their covers when the person approaches with a distance less or equal to 30 cm to throw garbage. Any approval waste basket is automatically discharged through an underground dump system using conveyor belt if the basket is full by 80% garbage and/or the basket moisture reaches to 40%.
Volume: 11
Issue: 3
Page: 2577-2585
Publish at: 2021-06-01

Control of power converter used for electric vehicle DC charging station with the capability of balancing distribution currents and reactive power compensation

10.11591/ijpeds.v12.i2.pp924-931
Moien A. Omar , Marwan M. Mahmoud
The global interest in electric cars aims to achieve sustainability in the transportation sector and reduce dependence on conventional cars that mainly depend on fossil fuels, the main source of emissions polluting the environment. However, the electric cars required electric fast chargers to charge the batteries with high currents in order to make the electric cars competitive with conventional cars that required a short time for filling fuel. Single-phase electric chargers make the distribution feeders with unbalanced currents as the single-phase loads and single-phase PV inverters. In the case of the unbalanced operation, one of the three phases may reach its maximum limit before other phases which leads to disconnect the transformer and thereby inefficient and unreliable system operation. This paper presents a control scheme for a three-phase, four-leg power converter that can be used as a fast charger for electric cars. Moreover, it can be used for balancing grid currents and for reactive power compensation. This will avoid frequent interruptions of distribution transformers due to unbalanced operation and reactive power loads. The distribution feeder considered to evaluate the control scheme consists of single-phase loads and inverters in addition to the proposed converter. The converter controls the charging power effectively and balancing the feeder currents. Moreover, during off charging time which is a possible manner for the charging station when the EV battery is fully charged the converter is effectively used for unbalanced mitigation and reactive power compensation. The simulated results show the effectiveness of the proposed control scheme.
Volume: 12
Issue: 2
Page: 924-931
Publish at: 2021-06-01

Measurement of colour coordinates of LEDs used in the automotive exterior lighting

10.11591/ijece.v11i3.pp2711-2724
Jan Latal , Patrik Hanulak , Jakub Kolar , Zdenek Wilcek , Tomas Stratil , Filip Sarlej
Article deals with dichromatic white light-emitting diode (LED’s) color coordinates used in automotive exterior lighting. This article also describes basic white automotive LED functionality and basic physical processes that create white light of these LEDs. It focuses on measuring color coordinates of white automotive LEDs with different temperature of LED and how the LED’s color depends on LED’s temperature. The article is comparing very important datasheet information of LED producers and values measured in the laboratory at university. The article contains statistical results of measurements and graphical representation of measured values and declared color bins which are very important for producers of headlamps for automotive companies.
Volume: 11
Issue: 3
Page: 2711-2724
Publish at: 2021-06-01

Enhancement of cloud performance metrics using dynamic degree memory balanced allocation algorithm

10.11591/ijeecs.v22.i3.pp1697-1707
Aparna Shashikant Joshi , Shayamala Devi Munisamy
In cloud computing, load balancing among the resources is required to schedule a task, which is a key challenge. This paper proposes a dynamic degree memory balanced allocation (D2MBA) algorithm which allocate virtual machine (VM) to a best suitable host, based on availability of random-access memory (RAM) and microprocessor without interlocked pipelined stages (MIPS) of host and allocate task to a best suitable VM by considering balanced condition of VM. The proposed D2MBA algorithm has been simulated using a simulation tool CloudSim by varying number of tasks and keeping number of VMs constant and vice versa. The D2MBA algorithm is compared with the other load balancing algorithms viz. Round Robin (RR) and dynamic degree balance with central processing unit (CPU) based (D2B_CPU based) with respect to performance parameters such as execution cost, degree of imbalance and makespan time. It is found that the D2MBA algorithm has a large reduction in the performance parameters such as execution cost, degree of imbalance and makespan time as compared with RR and D2B CPU based algorithms
Volume: 22
Issue: 3
Page: 1697-1707
Publish at: 2021-06-01

Improved DTC strategy of an electric vehicle with four in-wheels induction motor drive 4WDEV using fuzzy logic control

10.11591/ijpeds.v12.i2.pp650-661
Nair Nouria , Gasbaoui Brahim Ghazouni Abdelkader , Benoudjafer Cherif
In this paper, we will study a four-wheel drive electric vehicle (4WDEV)with two control strategies: conventional direct torque control CDTC and DTC based on fuzzy logic (DTFC). Our overall idea in this work is to show that the 4WDEV equipped with four induction motors providing the drive of the driving wheels controlled by the direct fuzzy torque control ensures good stability of the 4WDEV in the different topologies of the road, bends and slopes. and increases the range of the electric vehicle. Numerical simulations were performed on an electric vehicle powered by four 15 kW induction motors integrated into the wheels using the MATLAB / Simulink environment, where the reference speeds of each wheel (front and rear) are obtained using an electronic speed differential (ESD). This can eventually cause it to synchronize the wheel speeds in any curve. The speed of each wheel is controlled by two types of PI and FLC controllers to improve stability and speed response (in terms of setpoint tracking, disturbance rejection and climb time). Simulation results show that the proposed FLC control strategy reduces torque, flux and stator current ripple. While the4WDEV range was improved throughout the driving cycle and battery power consumption was reduced.
Volume: 12
Issue: 2
Page: 650-661
Publish at: 2021-06-01

Mitigating power quality disturbances in smart grid using FACTS

10.11591/ijeecs.v22.i3.pp1223-1235
Yahia M. Esmail , Ali H. Kasem Alaboudy , M. S. Hassan , Gamal M. Dousoky
Power quality (PQ) assurance is a vital part of electrical distribution networks. There are many advantages and benefits of improving PQ, especially in the modern/smart grid. Smart grid (SG) has a lot of complicated and sensitive electrical components (non-linear loads) in addition to renewable energy systems (wind-solar) that may also be a source of PQ disturbances. PQ problems harm personal life and national production. Static synchronous compensator (STATCOM) and unified power quality conditioner (UPQC) are among the fastest response flexible alternating current transmission systems (FACTS) installed in smart grids to mitigate power quality disturbances such as voltage fluctuations, sag, swell, and harmonics. In this research, STATCOM and UPQC are designed and simulated in MATLAB/Simulink to overcome PQ-related disruptions in smart grids. Accordingly, the differences between the proposed two solutions are highlighted across this research and renewable energy sources' reliability during faults. Therefore, the reader will be able to choose the appropriate FACTS devices. This study emphasizes the extent of the smart grid need for the FACTS. As per the given results of this study, STATCOM and UPQC have shown exemplary performance in the PQ improvement investigations conducted in the context of smart/modern grids.
Volume: 22
Issue: 3
Page: 1223-1235
Publish at: 2021-06-01
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