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29,922 Article Results

PID vs LQR controller for tilt rotor airplane

10.11591/ijece.v10i6.pp6309-6318
Aoued Houari , Imine Bachir , Della Krachai Mohamed , Mohamed Kara Mohamed
The main thematic of this paper is controlling the main manoeuvers of a tilt rotor UAV airplane in several modes such as vertical takeoff and landing, longitudinal translation and the most important phase which deal with the transition from the helicopter mode to the airplane mode and visversa based on a new actuators combination technique for specially the yaw motion with not referring to rotor speed control strategy which is used in controlling the attitude of a huge number of vehicles nowadays. This new actuator combination is inspired from that the transient response of a trirotor using tilting motion dynamics provides a faster response than using rotor speed dynamics. In the literature, a lot of control technics are used for stabilizing and guarantee the necessary manoeuvers for executing such task, a multiple Attitude and Altitude PID controllers were chosen for a simple linear model of our tilt rotor airplane in order to fulfill the desired trajectory, for reasons of complexity of our model the multiple PID controller doesnt take into consideration all the coupling that exists between the degrees of freedom in our model, so an LQR controller is adopted for more feasible solution of complex manoeuvering, the both controllers need linearization of the model for an easy implementation.
Volume: 10
Issue: 6
Page: 6309-6318
Publish at: 2020-12-01

A new exact equivalent circuit of the medium voltage three-phase induction motor

10.11591/ijece.v10i6.pp6164-6171
Laura Collazo Solar , Angel A. Costa Montiel , Miriam Vilaragut Llanes , Vladimir Sousa Santos , Abel Curbelo Colina
This paper proposes a new equivalent circuit for medium voltage and great power induction motors considering the more complete information given by the manufacturer. A methodology for obtaining the parameters of the equivalent circuit is presented, having this circuit the advantage of allowing the electrical calculation of all the power losses and the realization of the power balance. It is an achievement of this work a new way of calculating and representing the additional losses using a resistance located in the rotor circuit. Then, three types of losses are considered as a part of a power balance: the conventional or joule effect variable losses, the constant losses, and the additional losses. The proposed method is straight and non-iterative. It was applied to a case study motor of 6000 V and 2500 kW located at the Maximo Gomez Power Plant in Cuba.
Volume: 10
Issue: 6
Page: 6164-6171
Publish at: 2020-12-01

Currency hedging strategy using barrier options in the colombian market

10.11591/ijeecs.v20.i3.pp1634-1641
Mariana Arango-Franco , Miguel Jiménez-Gómez , Natalia Acevedo-Prins
One of the main problems for the growth of the Colombian market is the short variety of investment instruments found in the local market. In this way, an exchange rate hedging strategy is proposed using exotic options, specifically, barrier-type options. These types of options are not offered in the Colombian market. Monte Carlo simulation is used to determine the effect that the hedging strategy has on currency risk. From the results, it is concluded that the exchange risk is decreased with the hedging strategy because the 5th and 95th percentiles are lower than in the scenario without hedging. Finally, the code that was used to model the barrier options is explained.
Volume: 20
Issue: 3
Page: 1634-1641
Publish at: 2020-12-01

Performance investigation of stand-alone induction generator based on STATCOM for wind power application

10.11591/ijece.v10i6.pp5570-5578
Ahmed J. Ali , Mohammed Y. Suliman , Laith A. Khalaf , Nashwan S. Sultan
Self-Excited induction generators (SEIG) display a low voltage and frequency regulation due to variable applied load and input rotation speed. Current work presents a simulation and performance analysis of a three-phase wind-driven, SEIG connect to a three-phase load. In addition, an investigation of the dynamic operation of the induction generator from starting steady state until no-load operation. It is assumed that the input mechanical power is constant where the rotor of the SEIG rotates at a constant speed. The value of the excitation capacitance which is necessary to the operation of the induction generator also computed to ensure a smooth and self-excitation starting. The output voltage of the generator is adjusted by varying the reactive power injected by STATCOM. A 3-phase IGBT voltage source inverter with a fuel cell input supply is connected as STATCOM which is used to compensate for the reduction in the supply voltage and its frequency due to variation occurred in the applied loads. This work includes introducing a neuro-fuzzyy logic controller to enhance the performance of the SEIG by regulation the generated voltage and frequency The dynamic model of SEIG with STATCOM and loads are implemented using MATLAB/SIMULINK
Volume: 10
Issue: 6
Page: 5570-5578
Publish at: 2020-12-01

Reframing the effectiveness of feedback in improving teaching and learning achievement

10.11591/ijere.v9i4.20654
Anne Malar Selvaraj , Hazita Azman
Student feedback is established as an imperative learning and teaching technique, but feedback from students is less likely. The potential of feedback to boost learning outcomes refers to scholarly writing and is considered together as one of the most impressive methods for enhancing the success of students. In education, there is, nevertheless a lack of clarification about what feedback means and far less clarification on how one should interpret it. Feedback guides students to learn and supports them in order to achieve the aim of the lesson. The goal of this paper is to discuss teacherwritten reviews and obstacles to student feedback in order to recognise the usefulness of feedback in the education domain. Feedback from students illustrates the comprehensions, boundaries and features that knowledge should be compiled and employed to establish work or learning approach. The assessment study renders the appropriate feedback, and, in this manner, the students learn how to accomplish their learning goals. While feedback is not exclusively evaluated, these are the essential ingredients of making evaluation a mechanism for teachers’ and students’ future learning.
Volume: 9
Issue: 4
Page: 1055-1062
Publish at: 2020-12-01

The quality of image encryption techniques by reasoned logic

10.12928/telkomnika.v18i6.14340
Marwah Kamil; University of Basra Hussein , Kareem Radhi; University of Basra Hassan , Haider M.; University of Basra Al-Mashhadi
One form of data is digital images, because of their widespread of frequent exchange over the internet it is necessary to preserve the security and privacy of the images transmitted.There are many image encryption techniques that have different security levels and there are many standards and protocols fortesting the quality of encryption security. The cipher images can be evaluated using various quality measuring criteria, these measures quantify certain features of the image. If there are many methods that can be applied to secure images; the question is what is the most powerful scheme that can be use damong these methods? This research try to answer this question by taking three different encryption methods (rivest cipher 5 (RC5), chaotic and permutation) and measure their quality using the peek signal to noise ratio (PSNR),correlation, entropy, number of pixels changes rate (NPCR) and unified average changing intensity (UACI), the results of these criteria were input to a fuzzy logic system that was used to find the best one among them.
Volume: 18
Issue: 6
Page: 2992-2998
Publish at: 2020-12-01

Application of thermal imaging for detecting cold air leak location in cold storage

10.11591/ijaas.v9.i4.pp294-301
P. Pathmanaban , Shanmuga Sundaram Anandan , B. K. Gnanavel , C. P. Murigan
Nowadays Cold storage has been playing an important role in preserving the perishable food products like fruits, vegetables, dairy products, fish, and meat etc. The major problem of cold storage is unwanted energy transmission during the operation. It is necessary to maintain the constant temperature during storing the products. There are different kinds of energy loss happening during the operation. One of the major causes is cold air leaking from the inside of the cold room to outside. It is due to poor insulation and improper maintenance of cold storage. It is very difficult to identify the exact location of the leak by the naked eye. In this research work, the cold storage was inspected with the thermal imaging system. Thermal cameras are highly sensitive to temperature and it can detect the variation of temperature ranging from 0.1°C. The measured temperatures are further converted into a colour based pattern. It is known as thermogram. These colour-based thermal patterns are further processed for identifying energy transmission location. It is done by applying various image processing methods such as histogram equalization, diffusion error, otsu thresholding and morphologic function. These techniques were applied to images of cold storages and exact cold air transmission locations were identified.
Volume: 9
Issue: 4
Page: 294-301
Publish at: 2020-12-01

An efficient data masking for securing medical data using DNA encoding and chaotic system

10.11591/ijece.v10i6.pp6008-6018
Siddartha B. K. , Ravikumar G. K.
Data security is utmost important for ubiquitous computing of medical/diagnostic data or images. Along with must consider preserving privacy of patients. Recently, deoxyribose nucleic acid (DNA) sequences and chaotic sequence are jointly used for building efficient data masking model. However, the state-of-art model are not robust against noise and cropping attack (CA). Since in existing model most digits of each pixel are not altered. This work present efficient data masking (EDM) method using chaos and DNA based encryption method for securing health care data. For overcoming research challenges effective bit scrambling method is required. Firstly, this work present an efficient bit scrambling using logistic sine map and pseudorandom sequence using chaotic system. Then, DNA substitution is performed among them to resist against differential attack (DA), statistical attack (SA) and CA. Experiment are conducted on standard considering diverse images. The outcome achieved shows proposed model efficient when compared to existing models.
Volume: 10
Issue: 6
Page: 6008-6018
Publish at: 2020-12-01

A new clustering technique based on replication for MANET routing protocols

10.12928/telkomnika.v18i6.15998
Salma S.; Mansoura University Mohammed , A. I.; Mansoura University Abd-Elfattah , Mohamed A.; Mansoura University Mohamed
The cluster head nodes in most mobile ad hoc networks (MANET) clustering protocols take on an extraordinary role in managing routing information. The reliability, efficiency and scalability of the clustering in MANET will ultimately be dramatically impacted. In this work we establish a new approach to form the clusters in MANET called the square cluster-based routing protocol (SCBRP). That protocol is based on the theory of replication. The goal of the protocol is to achieve reliability, availability and scalability with in the MANET. The proposed protocol is evaluated by caring the performance analysis using the NS-3 simulator. The performance shows 50% improvementin data delivering ratio in large network size, also shows an improvement in network stability and availability which is reflected in energy consumption measurements and increase in the system lifetime to 20%.
Volume: 18
Issue: 6
Page: 3339-3345
Publish at: 2020-12-01

Low cost, high performance fuel cell energy conditioning system controlled by neural network

10.12928/telkomnika.v18i6.16426
Fredy H.; Universidad Distrital Francisco José de Caldas Martínez S. , Fernando Martínez; Universidad Distrital Francisco José de Caldas S. , Holman Montiel; Universidad Distrital Francisco José de Caldas Ariza
Fuel cells are an important option for the generation of renewable, efficient and environmentally friendly electricity. Although there are commercial applications in the industrial, residential and automotive sectors, it is not yet a mature technology and requires much research, particularly to reduce its costs to a level competitive with other technologies. This research is currently focused not only on the structure of the cell but also on the additional elements and sub systems required for its implementation as an energy solution. In this article, we propose an electrical energy conditioning scheme for the Formic acid fuel cell (direct formic acid fuel cellor DFAFC). This fuel cell was selected for its high performance, and low cost in low and medium power applications. The proposed system consists of a direct current-direct current (DC-DC) regulator supported by a power converter controlled by a Cortex-M3 ARM processor. This CPU is used to propagate a static neural network trained with the non-linear dynamics of the power converter. The power circuit is modeled and simulated to produce  the training parameters. The neural network is trained externally and runs off-line on the processor. The results show not only the regulation capacity of the control scheme but also its response speed to sudden changes in the load.
Volume: 18
Issue: 6
Page: 3116-3122
Publish at: 2020-12-01

A robust watermarking algorithm for medical images

10.11591/ijeecs.v20.i3.pp1601-1612
Ahmed Nagm , Mohammed Safy
Integrated healthcare systems require the transmission of medical images between medical centres. The presence of watermarks in such images has become important for patient privacy protection. However, some important issues should be considered while watermarking an image. Among these issues, the watermark should be robust against attacks and does not affect the quality of the image. In this paper, a watermarking approach employing a robust dynamic secret code is proposed. This approach is to process every pixel of the digital image and not only the pixels of the regions of non-interest at the same time it preserves the image details. The performance of the proposed approach is evaluated using several performance measures such as the mean square error (MSE), the mean absolute error (MAE), the peak signal to noise ratio (PSNR), the universal image quality index (UIQI) and the structural similarity index (SSIM). The proposed approach has been tested and shown robustness in detecting the intentional attacks that change image, specifically the most important diagnostic information.
Volume: 20
Issue: 3
Page: 1601-1612
Publish at: 2020-12-01

Fractional-order sliding mode controller for the two-link robot arm

10.11591/ijece.v10i6.pp5579-5585
Trong-Thang Nguyen
In this paper, the author proposes a sliding mode controller with the fractional-order for the two-link robot arm. Firstly, the model and dynamic equations of the two-link robot arm are presented. Based on these equations, the author builds the controller for each joint of the robot. The controller is a sliding mode controller with its order is not an integer value. The task of the controller is to adjust the torques acted on the joints in order for the angular coordinates of each link to coincide with the desired values. The effectiveness of the proposed control system is demonstrated through Matlab-Simulink software. The robot model and controller are built to investigate the system quality. The results show that the quality of the control system is very high: there is not the chattering phenomenon of torques, the response angles of each link quickly reach the desired values, and the static error equal to zero.
Volume: 10
Issue: 6
Page: 5579-5585
Publish at: 2020-12-01

The application of green YPO4:Ce3+,Tb3+ and red LiLaO2:Eu3+ layers to remote phosphor LED

10.12928/telkomnika.v18i6.13647
My Hanh Nguyen; Industrial University of Ho Chi Minh City Thi , Nguyen Thi Phuong; Posts and Telecommunications Institute of Technology Loan , Nguyen Doan Quoc; Ton Duc Thang University Anh
Remote phosphor structure is commonly limited in color quality, but has greater luminous flux when comparing to structures with in-cup or conformal coating. From this dilemma, various researches with advance modifications have been proposed to perfect the chromatic performance of remote structure. In this research, we reach higher color quality by obtaining better values in quality indcators such as color rendering index (CRI) and color quality scale (CQS) with the dual-layer phosphor in our remote white light-emitting diodes (WLEDs). The idea is to ultize WLEDs with 7000 K correlated color temperature (CCT) and create dual-layer configuration with yellow phosphor YAG:Ce3+ under green phosphor YPO4:Ce3+,Tb3+ or red phosphor LiLaO2:Eu3+. After that, we search for suitable concentration of LiLaO2:Eu3+ for addition in order to acquire the finest color quality. The result shows that WLED with LiLaO2:Eu3+ has better CRI and CQS as the higher the concentration of LiLaO2:Eu3+, the larger CRI and CQS due to increased light scattered in WLEDs. Meanwhile, the green phosphor layer YPO4:Ce3+,Tb3+ give advantages to luminous flux. However, the reduction in luminous flux and color quality occurs when the concentration of LiLaO2:Eu3+ and YPO4:Ce3+,Tb3+ over increase. Results are verified by Mie theory and Beer’s Law and can be applied to practical manufacturing of high quality WLEDs.
Volume: 18
Issue: 6
Page: 3216-3221
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

The detection of handguns from live-video in real-time based on deep learning

10.12928/telkomnika.v18i6.16174
Mohammed; Northern Technical University Ghazal , Najwan; Northern Technical University Waisi , Nawal; Northern Technical University Abdullah
Many people have been killed indiscriminately by the use of handguns in different countries. Terroristacts, online fighting games and mentally disturbed people are considered the common reasons for these crimes.  A real-time handguns detection surveillance system is built to overcome these badacts, based on convolutional neural networks (CNNs). This method is focused on the detection of different weapons, such as (handgun and rifles). The identification of handguns from surveillance cameras and images requires monitoring by human supervisor, that can cause errors. To overcome this issue,the designed detection system sends an alert message to the supervisor when aweapon is detected. In the proposed detection system, a pre-trained deep learning model MobileNetV3-SSDLite is used to perform the handgundetection operation. This model has been selected becauseit is fast and accurate in infering to integrate network for detecting and classifying weaponsin images. The experimental result using global handguns datasets of various weapons showed that the use of MobileNetV3 with SSDLite model bothenhance the accuracy level in identifying the real time handguns detection.
Volume: 18
Issue: 6
Page: 3026-3032
Publish at: 2020-12-01
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