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31,456 Article Results

Broadband planar 90 degrees loaded-stub phase shifter

10.12928/telkomnika.v18i6.15691
S. El; Hassan 1st University Marini , R.; Hassan 1st University Mandry , J.; Hassan 1st University Zbitou , A.; Hassan 1st University Errkik , A.; Hassan 1st University Tajmouati , M.; Microwave Group ESEO Latrach
The differential phase shifter is an interesting four-port passive microwave network composed of two separate lines, the main line and the reference line, and providing stable phase difference between the two output signals over the specified bandwidth of interest. The most common differential phase shifter is the coupled-line Schiffman phase shifter. In this paper, a novel 90 degrees differential microstrip phase shifter configuration employing a half wavelength transmission line loaded with three open stubs is presented, the proposed design could achieve excellent performance with low phase variation over a wide bandwidth compared to the standard Schiffman phase shifter. The simulated results accomplished with the use of CST Microwave Studio and advanced design system (ADS), were found to be in good agreement and have shown that the proposed loaded-stub phase shifter achieved less than 1.1 dB insertion loss, greater than 13 dB return loss and constant 90±5 degrees phase shift over an 89 percent bandwidth.
Volume: 18
Issue: 6
Page: 2834-2841
Publish at: 2020-12-01

Views of primary Thai teachers toward STREAM education

10.11591/ijere.v9i4.20595
Prasart Nuangchalerm , Veena Prachagool , Treekom Prommaboon , Juhji Juhji , Imroatun Imroatun , Khaeroni Khaeroni
This study employed survey method for exploring views of teachers toward science, technology, reading, engineering, arts and math science, technology, reading, engineering, arts and math (STREAM) education. Primary teachers were asked their views through questionnaires after STREAM education workshop. Results revealed that teachers have holistic view and having positive view towards STREAM education even though all of them are not science or mathematics teachers. Change in belief and way of practices can allow teachers to do STREAM education in every classroom, design-based learning and creative classroom should be promoted as well. However, holistic view will be more effective into classroom, technology and other supporting learning environments should be prepared.
Volume: 9
Issue: 4
Page: 987-992
Publish at: 2020-12-01

Offline signatures matching using haar wavelet subbands

10.12928/telkomnika.v18i6.17069
Zinah S.; Mustansiriyah University Abduljabbar , Zainab J.; University of Baghdad Ahmed , Noor; Mustansiriyah University Khalid Ibrahim
The complexity of multimedia contents is significantly increasing in the current world. This leads to an exigent demand for developing highly effective systems tosatisfy human needs. Until today, handwritten signature considered an important means that is used in banks and businesses to evidence identity, so there are many works triedto develop a method for recognition purpose. This paper introduced an efficient technique for offline signature recognition depending on extracting the local feature by utilizing the haar wavelet subbands and energy. Three different setsof features are utilized by partitioning the signature image into non overlapping blocks where different block sizes are used. CEDAR signature database is used asa dataset for testing purpose. The results achieved by this technique indicate a high performance in signature recognition.
Volume: 18
Issue: 6
Page: 2903-2910
Publish at: 2020-12-01

Investigation of deformation of the cornea during tonometry using FEM

10.11591/ijece.v10i6.pp5631-5641
Bharathi R. B. , Gopalakrishna Prabhu , Ramesh S. Ve , Rakshath Poojary , S. Meenatchi Sundaram
A three dimensional finite element model of the human eye is developed to evaluate the force which will be applied over the surface of cornea during tonometry and gonioscopy tests. The standard tonometers and gonioscopy experiences deformation from 0.5mm to 3mm of the cornea is adopted during both point contact and boundary contact on the surface of the cornea. The results demonstrate the maximum force experienced by the tonometer with point contact at the center of the cornea for the maximum possible deformation of the cornea during tonometry. The study also analyzes for the force experienced by the tonometer or goniolens with boundary layer contact for the defined deformation of the cornea along the direction from cornea towards the retina.
Volume: 10
Issue: 6
Page: 5631-5641
Publish at: 2020-12-01

Physical layer security and energy efficiency over different error correcting codes in wireless sensor networks

10.11591/ijece.v10i6.pp6673-6681
Mohammed Ahmed Magzoub , Azlan Abd Aziz , Mohammed Ahmed Salem , Hadhrami Ab Ghani , Azlina Abdul Aziz , Azwan Mahmud
Despite the rapid growth in the market demanding for wireless sensor networks (WSNs), they are far from being secured or efficient. WSNs are vulnerable to malicious attacks and utilize too much power. At the same time, there is a significant increment of the security threats due to the growth of the several applications that employ wireless sensor networks. Therefore, introducing physical layer security is considered to be a promising solution to mitigate the threats. This paper evaluates popular coding techniques like Reed solomon (RS) techniques and scrambled error correcting codes specifically in terms of security gap. The difference between the signal to nose ratio (SNR) of the eavesdropper and the legitimate receiver nodes is defined as the security gap. We investigate the security gap, energy efficiency, and bit error rate between RS and scrambled t-error correcting codes for wireless sensor networks. Lastly, energy efficiency in RS and Bose-Chaudhuri-Hocquenghem (BCH) is also studied. The results of the simulation emphasize that RS technique achieves similar security gap as scrambled error correcting codes. However, the analysis concludes that the computational complexities of the RS is less compared to the scrambled error correcting codes. We also found that BCH code is more energy-efficient than RS.
Volume: 10
Issue: 6
Page: 6673-6681
Publish at: 2020-12-01

Direct split-radix algorithm for fast computation of type-II discrete Hartley transform

10.12928/telkomnika.v18i6.16100
Mounir Taha; University of Tikrit Hamood
In this paper, a novel split-radix algorithm for fast calculation the discrete Hartley transform of type-II (DHT-II) is intoduced. The algorithm is established through the decimation in time (DIT) approach, and implementedby splitting a length N of DHT-II into one DHT-II of length N/2 for even-indexed samples and two DHTs-II of length N/4 for odd-indexed samples. The proposed algorithm possesses the desired properties such as regularity, inplace calculation and it is represented by simple closed form decomposition sleading to considerable reductions in the arithmetic complexity compared to the existing DHT-II algorithms. Additionally, the validity of the proposed algorithm has been confirmed through analysing the arithmetic complexityby calculating the number of real additions and multiplications and associating it with the existing DHT-II algorithms.
Volume: 18
Issue: 6
Page: 3067-3072
Publish at: 2020-12-01

Design of a controller for wheeled mobile robots based on automatic movement sequencing

10.12928/telkomnika.v18i6.16431
Holman Montiel; Universidad Distrital Francisco José de Caldas Ariza , Fredy H.; Universidad Distrital Francisco José de Caldas Martínez S. , Fernando Martínez; Universidad Distrital Francisco José de Caldas S.
There are many kinds of robots and among them the wheeled mobile robots (WMR) stand out, because they are relatively cheap and easy to build. These features make WMRs the test prototypes for control strategies or motion generation. In general, the controllers developed are based on sensory schemes that give an WMR the ability to travel through flat or obstructed environments. However, these strategies are highly reactive, i.e. they are based on the control-action scheme and are not adaptive; or, they are motion schemes built from simulations that assume the environmental conditions to determine the robot's path. In both cases, WMRs do not adapt perfectly to the change of environment, since the controller does not find appropriate movements for the  robot to move from one point to another. Therefore, this article proposesapartial solution to this problem, with a controller that generates sets of adaptive movements for an WMR to travel around its environment from the sensory perception information.
Volume: 18
Issue: 6
Page: 3088-3095
Publish at: 2020-12-01

Improving face recognition by artificial neural network using principal component analysis

10.12928/telkomnika.v18i6.16335
Shatha; Northern Technical University A. Baker , Hesham Hashim; Northern Technical University Mohammed , Hanan A.; The General Directorate of Education in Nineveh Governorate Aldabagh
The face-recognition system is among the most effective pattern recognition and image analysis techniques. This technique has met great attention from academic and industrial fields because of its extensive use in detecting the identity of individuals for monitoring systems, security and many other practical fields. In this paper, an effective method of face recognition was proposed. Ten person's faces images were selected from ORL dataset, for each person (42) image with total of (420) images as dataset. Features are extracted using principle component analysis PCA to reduce the dimensionality of the face images. Four models where created, the first one was trained using feed forward back propagation learning (FFBBL) with 40 features, the second was trained using 50 features with FFBBL, the third was trained using the same features but using Elman Neural Network. For each person (24) image used as training set for the neural networks, while the remaining images used as testing set. The results showed that the proposed method was effective and highly accurate. FFBBL give accuracy of (98.33,97.14) with (40, 50) features respectively, while Elman gives (98.33, 98.80) for with (40, 50) features respectively.
Volume: 18
Issue: 6
Page: 3357-3364
Publish at: 2020-12-01

A beamforming study of the linear antenna array using grey wolf optimization algorithm

10.11591/ijeecs.v20.i3.pp1538-1546
Asma Issa Mohsin , Asaad S. Daghal , Adheed Hasan Sallomi
The grey wolf optimization (GWO) algorithm is considered an inspired meta-heuristic algorithm, which inspired by the social hierarchy and hunting behavior of the grey wolves. GWO has a high-performance capability of solving constrained, as well as unconstrained optimization problems. In this paper, the beamforming of smart antennas in a code division multiple access system based on the GWO algorithm is investigated. The sidelobe level (SLL) is minimized along with peak sidelobe level reduction, as well as an optimal beam pattern has been accomplished by using GWO to uniform linear antenna arrays. In this work, an amplitude is introduced as constant, while the interspacing distance between antenna array elements and the number of elements in a linear array are variables. The simulation results show that a faster convergence and likely high accurate beamforming are gained using GWO based method. Finally, it is shown that the GWO outperforms the genetic algorithm (GA) based method.
Volume: 20
Issue: 3
Page: 1538-1546
Publish at: 2020-12-01

A new block cipher for image encryption based on multi chaotic systems

10.12928/telkomnika.v18i6.13746
Donia Fadhil; Mustansiyiah University Chalob , Amal Abdulbaqi; Mustansiyiah University Maryoosh , Zainab Mohammed; Mustansiyiah University Esa , Elaf Nassir; Mustansiyiah University Abbud
In this paper, a new algorithm for image encryption is proposed based on three chaotic systems which are Chen system,logistic map and two-dimensional (2D) Arnold cat map. First, a permutation scheme is applied to the image, and then shuffled image is partitioned into blocks of pixels. For each block, Chen system is employed for confusion and then logistic map is employed for generating subsititution-box (S-box) to substitute image blocks. The S-box is dynamic, where it is shuffled for each image block using permutation operation. Then, 2D Arnold cat map is used for providing diffusion, after that XORing the result using Chen system to obtain the encrypted image.The high security of proposed algorithm is experimented using histograms, unified average changing intensity (UACI), number of pixels change rate (NPCR), entropy, correlation and keyspace analyses. 
Volume: 18
Issue: 6
Page: 2983-2991
Publish at: 2020-12-01

Comparative study of three different bridge-less converters for reduction of harmonic distortion in brushless DC motor

10.11591/ijeecs.v20.i3.pp1185-1193
Santanu Mondal , Madhurima Chattopadhyay
This paper represents a comparative study of three different types of DC-DC converter that can be used for reduction of total harmonic distortion (THD) in stator current, back electromotive force (EMF) and torque of brush less DC motor. In addition, the topologies of these converters are analysed, and the THD of the output characteristics have also been studied. In this work, SEPIC, Zeta and Flyback converters are considered and their outputs are fed to the BLDCM with the help of universal bridge or six step inverter. Moreover the THD of the output voltages are not only measured for three converters but also reduced by tuning the parameters. At first these three converters are modeled in MATLAB/ Simulink based simulation platform and studied the performance individually and further executed with hardware circuitry. Finally the output parameters from both software simulation and real time hardware are compared for these three converters separately and got satisfactory similar results. Again we studied the performance with these converters in terms of efficiency while fed in the commutation drive circuitry of BLDCM by considering minimum THD. From this comparative simulation results, it has been observed that Zeta converter showed maximum efficiency. Therefore, in real time hardware implementation, the commutation drive circuitry of BLDCM is studied with Zeta converter. With this configuration, a comparatively low THD of stator current, back EMF and electromagnetic torque have been achieved in BLDCM with PID controller.
Volume: 20
Issue: 3
Page: 1185-1193
Publish at: 2020-12-01

Quantitative analysis of Mouza map image to estimate land area using zooming and Canny edge detection

10.12928/telkomnika.v18i6.16179
Yeasmin Ara; East Delta University Akter , Md. Ataur; Premier University Rahman , Mohammad; University of Chittagong Osiur Rahman
In Bangladesh, mouza map is used to maintain the record of land measurement, which is a form of interpreting land ownership as well as estimation. Unfortunately, the automatic determination of land is still under development. As a result, land administrators have to encounter multiple hurdles while evaluating any area by employing local civil engineers. Thus, our country needs an automated land estimation system so that it can reduce time, cost and other difficulties which inspired us to develop a system that requires only mouza map image. Once image acquisition is done, we applied the curvature interpolation techniqueto zoom the map that helps to select any area by the Area Selection Method. The selected area is then segmented by employing the Canny edge detection method. Finally, the area is calculated from the segmented image and extracted features of the selected location. Compared to the field measurement, the system gave the accuracy of 89.8%. Hence, the land administrators will be able to provide the land information to the landowners promptly.
Volume: 18
Issue: 6
Page: 3293-3302
Publish at: 2020-12-01

Multi-objective Pareto front and particle swarm optimization algorithms for power dissipation reduction in microprocessors

10.11591/ijece.v10i6.pp6549-6557
Diary R. Sulaiman
The progress of microelectronics making possible higher integration densities, and a considerable development of on-board systems are currently undergoing, this growth comes up against a limiting factor of power dissipation. Higher power dissipation will cause an immediate spread of generated heat which causes thermal problems. Consequently, the system's total consumed energy will increase as the system temperature increase. High temperatures in microprocessors and large thermal energy of computer systems produce huge problems of system confidence, performance, and cooling expenses. Power consumed by processors are mainly due to the increase in number of cores and the clock frequency, which is dissipated in the form of heat and causes thermal challenges for chip designers. As the microprocessor’s performance has increased remarkably in Nano-meter technology, power dissipation is becoming non-negligible. To solve this problem, this article addresses power dissipation reduction issues for high performance processors using multi-objective Pareto front (PF), and particle swarm optimization (PSO) algorithms to achieve power dissipation as a prior computation that reduces the real delay of a target microprocessor unit. Simulation is verified the conceptual fundamentals and optimization of joint body and supply voltages (Vth-VDD) which showing satisfactory findings.
Volume: 10
Issue: 6
Page: 6549-6557
Publish at: 2020-12-01

A brief review: basic coil designs for inductive power transfer

10.11591/ijeecs.v20.i3.pp1703-1716
Nadia Nazieha Nanda , Siti Hajar Yusoff , Siti Fauziah Toha , Nurul Fadzlin Hasbullah , Amelia Shafina Roszaidie
The inductive power transfer (IPT) has contributed to the fast growth of the electric vehicle (EV) market. The technology to recharge the EV battery has attracted the attention of many researchers and car manufacturers in developing green transportation. In IPT charging system, the coil design is indispensable in enhancing the EV battery charging process performance. This paper starts by describing the two charging techniques; static charging and dynamic charging before further presents the IPT system descriptions. Afterwards, this paper describes a brief review of coil designs which discusses the critical factors that affect the power transmission efficiency (PTE) including their basic designs, design concepts and features merits. The discussions on the basic coil designs for IPT are of the circular spiral coil (CSC), square coil (SC), rectangular coil (RC), and double-D coil (DDC). Furthermore, the significant advantages and limitations of each research on different geometries are analyzed and discussed in this paper. Finally, this paper evaluates some essential aspects that influence the coil geometry designs in practical.
Volume: 20
Issue: 3
Page: 1703-1716
Publish at: 2020-12-01

Analysis of HVDC breakdown characteristic of LLDPE-natural rubber added with biofiller as high voltage insulating material

10.11591/ijeecs.v20.i3.pp1203-1209
Nor Izzati Mohd Salleh , Nor Akmal Mohd Jamail , Nishanti Suntharasaka , Nor Shahida Mohd Jamail , Mohamad Farid Sies , Qamarul Ezani Kamarudin , Mohamed Afendi Mohamed Piah
The influence of solid insulation has been investigated by few researchers. The mechanism of solid breakdown is important in insulation studies. In this research, testing on linear low density polythylene (LLDPE) with natural rubber (NR) and different weight concentration of biofiller are conducted under high voltage direct voltage (HVDC) by using needle and sphere types of electrode arrangements. Oil palm empty fruit bunch (OPEFB) and pineapple leaf fiber (PALF) are the biofillers used for the samples development. The LLDPE-NR samples consists of different weight percentages of biofiller which are 0%, 2.5%. 5.0%. 7.5% and 10% with 3mm thickness. The voltage has been increased until the breakdown occurs. Based on the results obtained, OPEFB and PALF with the highest weight percentages of 10% showed the highest damage voltages of 59.09kV and 59.36kV. It has been proven that both samples with the highest filler content have appropriate insulating properties. In conclusion, the addition of biofiber to LLDPE-NR has improved the breakdown properties compared to pure LLDPE.
Volume: 20
Issue: 3
Page: 1203-1209
Publish at: 2020-12-01
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