Original Research Paper
Electronics
S. Ranjbaran; A. Roudbari; S. Ebadollahi
Abstract
Background and Objectives: Using field calibration methods without precision laboratory equipment, systematic faults of inertial sensors can be reduced and measurement accuracy can be increased. Methods: In this paper, a simple and fast method called improved least squares is used to find calibration ...
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Background and Objectives: Using field calibration methods without precision laboratory equipment, systematic faults of inertial sensors can be reduced and measurement accuracy can be increased. Methods: In this paper, a simple and fast method called improved least squares is used to find calibration coefficients of an accelerometer including bias, scale factor and non-orthogonality. In this method, this principal is used that the magnitude of acceleration measured by accelerometer in static condition is equal to the magnitude of gravity vector and a cost function is then defined. Also, in gyroscope field calibration, sensor is rotated manually around all three axes separately and then it is put in the static mode. Changes in the angle obtained from gyroscope at each movement are compared with the ones obtained from the calibrated accelerometer. Calibration coefficients including bias and scale factor are obtained using least squares method. Results: Simulation results in MATLAB show that the measurement accuracy of accelerometer after calibration has improved by about 60% and the accuracy of the gyroscope has increased by about 40%. Also, comparison with the other methods proves that the proposed method performs well in the accuracy, speed, time required, and the effect of noise changes. Conclusion: This paper by finding a fast, simple, and low-cost field calibration method to calibrate MEMS accelerometer and gyroscope without using accurate laboratory equipment can help a wide range of industries that use advanced and expensive sensors or use expensive laboratory equipment to calibrate their sensors, to decrease their costs.======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Electronics
H. Firoozi; M. Imanieh
Volume 6, Issue 1 , January 2018, Pages 7-13
Abstract
< p>Background and Objectives: In this article, the functionality of solar cells structure based on CuIn1-xGaxSe2 is investigated. This type of solar cell consists of different layers, namely, ZnO (TCO layer), Cd_S (Buffer layer), CIGS (Absorbent layer), and MO (Substrate layer). Two layers, Cd_S ...
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< p>Background and Objectives: In this article, the functionality of solar cells structure based on CuIn1-xGaxSe2 is investigated. This type of solar cell consists of different layers, namely, ZnO (TCO layer), Cd_S (Buffer layer), CIGS (Absorbent layer), and MO (Substrate layer). Two layers, Cd_S and CIGS, form a PN Junction. < p>Methods: CIGS thin film solar cell is simulated using SILVACO software. The absorbent layer doping was originally changed. Later doping was kept constant and P-type layer of InAsP was added. Their effect on cell function was observed and examined. It was observed that after doping some parameters of the solar cell have improved whilst some others have decreased. It was also concluded that examined increase or decrease in the amount of dopant would reduce our efficiencies of solar cell. < p>Results: Added the InAsP layer leads to increased open circuit voltage, short circuit current and the solar cell power, consequently gives the efficiency about 33.2%, which is an acceptable efficiency. < p>Conclusion: It was clear that extreme increase or decrease in the amount of dopant in the absorbent layer can change solar cell parameters, and can improve cell functionality. < p>The amount of dopants can also alter some other solar cell parameters which are not desirable, the added InAsP layer leads to increased open circuit voltage, and short circuit current and the solar cell power, consequently gives the about 33.2%, efficiency which is an acceptable efficiencies.======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Artificial Intelligence
M. Abdolahi; M. Zahedi
Volume 6, Issue 1 , January 2018, Pages 15-24
Abstract
< p>Background and Objectives: Discourse coherence modeling evaluation becomes a critical but challenging task for all content analysis tasks in Natural Language Processing subfields, such as text summarization, question answering, text generation and machine translation. Existing methods like ...
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< p>Background and Objectives: Discourse coherence modeling evaluation becomes a critical but challenging task for all content analysis tasks in Natural Language Processing subfields, such as text summarization, question answering, text generation and machine translation. Existing methods like entity-based and graph-based models are engaging in semantic and linguistic concepts of a text. It means that the problem cannot be solved very well and these methods are only very limited to available word co-occurrence information in the sequential sentences within a short part of a text. One of the greatest challenges of the above methods is their limitation in long documents coherence evaluation and being suitable for documents with low number of sentences. Methods: Our proposed method focuses on both local and global coherence. It can also assess the local topic integrity of text at the paragraph level regardless of word meaning and handcrafted rules. The global coherence in the proposed method is evaluated by sequence paragraph dependency. According to the derived results in word embeddings, by applying statistical approaches, the presented method incorporates the external word correlation knowledge into short and long stories to assess both local and global coherence, simultaneously. Results: Using the effect of combined word2vec vectors and most likely n-grams, we show that our proposed method is independent of the language and its semantic concepts. The derived results indicate that the proposed method offers the higher accuracy with respect to the other algorithms, in long documents with a high number of sentences. Conclusion: Our current study, comparing our proposed method with BGSEG method showed that the mean degree of coherence evaluation 1.19 percent improvement. The results in this study also indicate improvement results are much more in larger texts with more sentences.======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Communications
F. Yousefi Moghadam; B. Afzali; F. Nadi; R. Zallbeygi
Abstract
Background and Objectives: In this paper, an ultra-wide stopband microstrip low pass filter (LPF) with sharp roll-off and compact size is designed and fabricated. Also, proposed filter is designed, simulated, optimized, fabricated and measured and we can see a good agreement between the simulations and ...
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Background and Objectives: In this paper, an ultra-wide stopband microstrip low pass filter (LPF) with sharp roll-off and compact size is designed and fabricated. Also, proposed filter is designed, simulated, optimized, fabricated and measured and we can see a good agreement between the simulations and measurement results. Methods: T-shaped and stepped impedance have been used, because these structures have a very small dimensions. This method provides a suitable cut off frequency. Results: The cut off frequency at -3dB is 3.1GHz. In the proposed structure, the insertion loss is lower than 0.12dB and the return loss is greater than 15dB. In order to achieve a -20dB attenuation level in the stopband, a modified L-shaped structure is utilized. This filter has an ultra-wide stopband that is expanded from 3.37GHz to 37.5GHz. Also, the suppression level is greater than -20dB. The fabricated LPF has a size about 16.6 × 13.5 mm2 which is equal to 0.28ƛg × 0.22ƛg, where ƛg is the guided wavelength at 3.1GHz, which is very small. Conclusion: A microstrip LPF with 3.1GHz cut-off frequency consisting of T-shaped and stepped impedance resonators has been proposed, simulated and fabricated. The transition band (-3 to -40dB) is 0.38GHz, which is a very sharp response. The stopband of the proposed filter is from 3.37 to 37.5 GHz which is equal to 12.1fc. There was a significant agreement between the simulation and the measured results. With all these features, these filters are widely used in wireless communication systems.======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Software
A. Saberi nejad; R. Tavoli
Abstract
Background and Objectives: Nowadays, data mining is one of the most significant issues. One field of data mining is a mixture of computer science and statistics which is considerably limited due to increase in digital data and growth of computational power of computers. One of the domains of data mining ...
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Background and Objectives: Nowadays, data mining is one of the most significant issues. One field of data mining is a mixture of computer science and statistics which is considerably limited due to increase in digital data and growth of computational power of computers. One of the domains of data mining is the software cost estimation category. Methods: In this article, classifying techniques of learning algorithm of machine and COCOMO model as the most common estimation model of software costs are presented. Then, the analysis method of principal component approach is presented. Results: This article presents a suitable method to improve the performance of the software cost estimation. Moreover, the basic data set is decreased and is turned into a new collection by using this method. Among the features, the best are extracted. The algorithms of several classifications are assessed by applying this method. Finally, the evidence for accuracy of our claims in terms of increase in estimation accuracy of software costs is presented. Conclusion:. The results proved that the suggested method could have significant influence on models of decision tree, naïve Bayes and nearest neighborhood by decreasing dimension of input data and turning it into data. ======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Power
P. Vahedi; B. Ganji
Abstract
Background and Objectives: One of the main drawbacks of switched reluctance motors (SRM) is high acoustic noise and significant research has been done to reduce it. In addition, reduction of temperature rise within the machine is usually considered as one of the most important goals of design. Therefore, ...
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Background and Objectives: One of the main drawbacks of switched reluctance motors (SRM) is high acoustic noise and significant research has been done to reduce it. In addition, reduction of temperature rise within the machine is usually considered as one of the most important goals of design. Therefore, a shape design method is introduced in the present paper for the SRM by which both heat transfer and acoustic noise are improved. Methods: For evaluation of the proposed shape design method, a simulation model based on finite element method (FEM) is also developed to predict both the temperature rise within the machine and the produced noise. The simulation model is created using ANSYS finite element (FE) package and it is build up totally as a parametric model in ANSYS parametric design language. Since the convection heat transfer coefficients depend on the temperature rise, they are determined in the developed thermal model based on an iterative algorithm. Results: The proposed shape design method is applied to a typical 8/6 SRM and simulation results including temperature distribution in various sections of the machine, displacement of stator and sound pressure level (SPL) are presented. Conclusion: Based on the obtained simulation results, it is illustrated that the temperature rise and the noise of the SRM could be improved significantly using the introduced shape design method.======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Electronics
M. Feli; F. Parandin
Abstract
Background and Objectives: Solar cell is an electronic device which harvest photovoltaic effect and transform light energy to electricity. An efficient double junction InGaN/CIGS solar cell can be simulated using Silvaco ATLAS software. In this study, a thin CdS top cover layer is used as the anti-reflector ...
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Background and Objectives: Solar cell is an electronic device which harvest photovoltaic effect and transform light energy to electricity. An efficient double junction InGaN/CIGS solar cell can be simulated using Silvaco ATLAS software. In this study, a thin CdS top cover layer is used as the anti-reflector layer. Methods: To reach the current matching condition, changing the thickness of this CdS layer, we can enhance the short-circuit currents of both the top and bottom cells. To gain a desired efficiency, different design parameters, such as the doping concentrations and the thicknesses of the various layers of the cell are optimized. This cell is designed to be used in a real environmental situation. Results: By using the appropriate parameters, and under matching conditions, the efficiency is optimized as well as the filling factor is increased. Considering the proposed structure and the simulation results, an optimum efficiency of 41.87% is achieved and also the obtained fill factor is equal to 75.16%. Conclusion: In this paper, a new structure for an efficient double junction InGaN/CIGS solar cell, was proposed. In our proposed structure, a thin CdS layer is used as the anti-reflector layer. To get a desired efficiency, different design parameters, such as the doping concentrations and the thicknesses of various layers of the cells were optimized. ======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Software
M. Sadeghzadeh Hemayati; H. Rashidi
Abstract
Background and Objectives: One of the major challenges in software engineering is how to respond to the desolate state of high-quality software development in a timely and cost-effective manner. Many studies have been conducted in an attempt to formalize the quality of software. However, according to ...
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Background and Objectives: One of the major challenges in software engineering is how to respond to the desolate state of high-quality software development in a timely and cost-effective manner. Many studies have been conducted in an attempt to formalize the quality of software. However, according to the recent researches, the lack of comprehensive quality model is rooted in neglecting all quality aspects. Methods: In this study, we review nineteen quality models and classify them from three different perspectives, including structural, behavioral, and basic and derived aspects. The main aim is to specify and extract the more comprehensive set of quality factors to evaluate software quality. Results: This paper compares the different quality models and analyzes the factors to draw the necessary aspects in comprehensive quality models. Since the software quality involves several engineering tasks and several players who deal with quality concepts during software life cycle according to their various roles, in various phases and different artifacts, comprehensive quality models must consider many factors. Conclusion: These factors are in different aspects such as the measurement time in different development phases, product as well as process-related quality factors, a set of quality metrics measureable on the different type of artifacts such as document, model and source code, and finally a specific mechanism to apply dynamic weights to quality factors to determine their impacts on final quality of a product based on its application domain. ======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Power
S.E. Abdollahi; M. Mirzaei
Abstract
Background and Objectives: Linear induction motors (LIMs) are widely employed in rail transportation systems due to their robust, simple and low cost structure. Methods: Several methods have evaluated various topologies' performances in the literature. These methods are more and less effective ...
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Background and Objectives: Linear induction motors (LIMs) are widely employed in rail transportation systems due to their robust, simple and low cost structure. Methods: Several methods have evaluated various topologies' performances in the literature. These methods are more and less effective in the intended structures. In this paper, a new two-dimensional analytical method is presented in order to predict developed thrust force of a single-sided linear induction motor with a solid iron secondary. Results: The skin and saturation effects of the induced eddy currents in the solid iron of the secondary are considered in the proposed method. The analytical results are then compared with the 2D finite element simulation and the experimental ones of the research work of Gieras et al. . Conclusion: Results confirm the accuracy of the proposed analytical and finite element methods for the analysis and design of linear induction motors with solid iron secondary. ======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Control
N. Azam Baleghi; M.H. Shafiei
Abstract
Background and Objectives: Nowadays, because of accuracy, speed, cost, and flexibility of digital control laws, control systems are implemented by computers, microprocessors or DSP chips. Therefore, many investigators have recently focused on the design of discrete-time controllers and computer-based ...
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Background and Objectives: Nowadays, because of accuracy, speed, cost, and flexibility of digital control laws, control systems are implemented by computers, microprocessors or DSP chips. Therefore, many investigators have recently focused on the design of discrete-time controllers and computer-based control. Methods: In this paper, a sliding mode controller based on the disturbance estimation is designed for a class of discrete-time nonlinear affine systems. Based on two disturbance compensator schemes, static and dynamic, procedures of sliding mode controller design are proposed for the discretetime system. Results: In the case of measurable state variables, the instantaneous value of disturbances can be estimated based on the value of states and control signals. In two proposed control laws, there is no switching expression to induce the problem of chattering. Moreover, based on the necessary and sufficient quasi-sliding mode condition proposed by Sarpturk, boundedness and robustness of the proposed controllers is evaluated. In the case of constant or slowly time-varying disturbances, the quasi-sliding mode band converges asymptotically to zero and in this case, the proposed method is converted to the ideal sliding mode. Finally, two examples are provided to verify the proposed control laws and to compare the performance of the proposed controllers. Conclusion: In this paper, a sliding mode controller based on the disturbance estimator was designed for a discrete-time nonlinear affine system. Due to the effectiveness of disturbance estimators in the performance of controllers, two kinds of disturbance estimators were considered. ======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Power
B. Ehsan maleki; H. Beiranvand
Abstract
Background and Objectives: In this paper, a non-typical design method of flexible AC transmission systems power oscillation damping (FACTS-POD) controller is proposed to increase the efficiency of these devices. In all of the introduced FACTS-POD devices (taking IPFC-POD as an example), the supplementary ...
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Background and Objectives: In this paper, a non-typical design method of flexible AC transmission systems power oscillation damping (FACTS-POD) controller is proposed to increase the efficiency of these devices. In all of the introduced FACTS-POD devices (taking IPFC-POD as an example), the supplementary controller is designed based upon a conventional approach (i.e., based on optimization algorithms) and using a different method can be useful. Methods: In this paper, the graduated modal decomposition control (GMDC) is utilized as a specific strategy for POD controller design. Moreover, the dynamic model of the multi-machine power system with the presence of IPFC devices has been developed. Results: The obtained model is nonlinear; however, it is linearized around the operating point to design the controllers. The overall paper's structure is based upon the two scenarios, in the first of which conventional method for IPFC-POD design has been analyzed there upon the result compared with the introduced method in the second scenario. Finally, to ascertain responsive of the designed controller to load changes and stability of the system, the probabilistic sensitivity indices (PSIs) are investigated over a large set of operating conditions. As a verification, the time-domain simulations on a 10-machine power system emphasize the analysis of dynamic results and their information under the considered conditions. Conclusion: In general, the specific purpose of this paper is to enhance of the dynamic stability of concerned inter-area modes. The proposed method, especially using GRSA, offers better stability characteristics than the results of previous methods. ======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
Original Research Paper
Communications
M. Safkhani
Abstract
Background and Objectives: To overcome the security flaw of RAPP authentication protocol, Zhuang et al. proposed a novel ultralightweight RFID mutual authentication protocol, called R2AP. In this paper, we first propose a new desynchronization attack against this protocol. Methods: To extract the secret ...
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Background and Objectives: To overcome the security flaw of RAPP authentication protocol, Zhuang et al. proposed a novel ultralightweight RFID mutual authentication protocol, called R2AP. In this paper, we first propose a new desynchronization attack against this protocol. Methods: To extract the secret ID, linear cryptanalysis is used, which is a tool mostly for attack block ciphers. Results: Our proposed desynchronization attack succeeds with the probability almost 1 and requires an adversary to initiate 1829 sessions of the protocol with the tag. On the other hand, the protocol updates the tag and the reader secretes to provide the tag holder privacy. However, it is shown that a passive adversary who eavesdrops only two sessions of the protocol can trace the tag with the probability of 0.921. In addition, passive attack for which the adversary can extract the secret ID of the tag is presented assuming that the adversary eavesdropped 128 sessions of the protocol, its success probability would be 0.387. Conclusion: It was shown that R2AP suffers from desynchronization, traceability, and disclosure attacks, where the two later attacks work in passive adversary model.======================================================================================================Copyrights©2018 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.======================================================================================================
