@article { author = {Yousefi, S. and Hosseini Biyouki, M. M. and Zaboli, A. and Askarian Abyaneh, H. and Hosseinian, S. H.}, title = {Harmonic Elimination of 25 kV AC Electric Railways Utilizing a New Hybrid Filter Structure}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {3-10}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.811}, abstract = {Thyristor rectifiers are widely used in electric railways in order to control the speed. As a consequence of their usage in addition to substantial input lead current, an enormous amount of harmonics is injected into the grid. To avoid such harmonics as well as reactive power compensation, reactive power hybrid filters consisting of active and passive filters are utilized. Regarding different passive and active filters connection in a hybrid filter, various configurations of hybrid filters are possible. Each of these configurations has different functionality in harmonic elimination and reactive power compensation. Since electric railway has a non-linear and variable nature, a novel hybrid filter structure is designed that compensates reactive power and eliminates harmonics to attain desired harmonic level regarding the conventional allowable harmonics level standards. The designed filter model is simulated in MATLAB/SIMULINK and then applied to a harmonic model of an electric railway. Since electric railways are single phase loads, specific three-phase to two-phase transformers are required to feed the load. To attain such purpose, adaptive transformer is utilized in this paper. The proposed model has properly overcome the deficiencies of active and passive filters as well as demonstrating an appropriate performance in reduction of total harmonic distortion (THD).}, keywords = {Harmonics elimination,Hybrid filters,Non-linear loads,Reactive power compensation}, url = {https://eej.aut.ac.ir/article_811.html}, eprint = {https://eej.aut.ac.ir/article_811_1c874ed52a4283440954bb06c7ed5dd7.pdf} } @article { author = {Saidi, M. and Hassanpoor, H. and Azizi Lari, A.}, title = {Proposed new signal for real-time stress monitoring: Combination of physiological measures}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {11-18}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.822}, abstract = {Human stress is a physiological tension that appears when a person responds to mental, emotional, or physical chal-lenges. Detecting human stress and developing methods to manage it, has become an important issue nowadays. Au-tomatic stress detection through physiological signals may be a useful method for solving this problem. In most of the earlier studies, long-term time window was considered for stress detection. Continues and real-time representation of the stress level is usually done through one physiological signal. In this paper, a real-time stress monitoring system is pro-posed which shows the user a new signal for feedback stress level. This signal is combined of weighted features of gal-vanic skin response and photoplethysmography signals. The features are defined in 20-sec time windows. Correlation feature selection and linear regression methods are used for feature selection and feature combination respectively. Furthermore, a set of experiments was conducted for training and testing of the proposed model. The proposed model can represent the relative stress level perfectly and has 79% accuracy for classifying the stress and relaxation phases into two categories by a determined threshold.}, keywords = {stress detection,physiological signals,stress modeling,biofeedback}, url = {https://eej.aut.ac.ir/article_822.html}, eprint = {https://eej.aut.ac.ir/article_822_25739a0be4b69b7521e295fc51f57d69.pdf} } @article { author = {Hatamkhani, A. and Ghorbani, A.}, title = {A Higher Order B-Splines 1-D Finite Element Analysis of Lossy Dispersive Inhomogeneous Planar Layers}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {19-22}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.823}, abstract = {In this paper we propose an accurate and fast numerical method to obtain scattering fields from lossy dispersive inhomogeneous planar layers for both TE and TM polarizations. A new method is introduced to analyze lossy Inhomogeneous Planar Layers. In this method by applying spline based Galerkin’s method of moment to scalar wave equation and imposing boundary conditions we obtain reflection and transmission from inhomogeneous layer. Moreover we obtain both electric and magnetic fields in the inhomogeneous layers. The method employs a set of spline-harmonic basis functions and leads to one-dimensional integrals for system matrix elements. This fact along with the higher order nature of the basis functions provides an accurate method for the analysis of the aforementioned dispersive lossy inhomogeneous layers. The accuracy and the convergence behavior of the method are studied through several numerical examples and the results are compared with the exact solutions to establish the validity of the proposed method.}, keywords = {Nonhomogeneous media,B-Splines,Dispersive media,Galerkin’s method,Transmission and Reflection}, url = {https://eej.aut.ac.ir/article_823.html}, eprint = {https://eej.aut.ac.ir/article_823_34f1fba6b694f264c41241feb4cf2a84.pdf} } @article { author = {Poursajadi, S. and Madani, M. H.}, title = {Performance Analysis of Wireless Cooperative Networks with Iterative Incremental Relay Selection}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {23-30}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.819}, abstract = {In this paper, an iterative incremental relay selection (IIRS) scheme is considered for wireless cooperative networks in order to increase the reliability of transmission. Different from the conventional incremental relay selection which incrementally selects a best relay for only one iteration; the IIRS scheme iteratively applies the incremental relaying and relay selection processes. To evaluate the performance of the proposed scheme, outage probability and average capacity of the system are investigated through analysis and simulation. This scheme provides (I+1) diversity order in a system of I relays as the highest diversity order which can be provided by all participate (AP) cooperative scheme. Also, it is shown that the IIRS scheme combats with the spectral efficiency loss resulted by applying all of the relays. As the cost of improvement, it is seen that the average required feedback bits to implement the IIRS scheme leads to I*log2(I+1) bits at low signal to noise ratio (SNR), while it leads to log2(I+1) bits at higher SNRs which is acceptable for implementation. Considering the provided improvement along with the limited feedback reveals that the IIRS scheme can be applied as an efficient scheme compared to the other common cooperative schemes. Finally, numerical results indicate the validity of the analysis especially at high SNRs.}, keywords = {Cooperative Communication,Incremental Relaying,Relay Selection}, url = {https://eej.aut.ac.ir/article_819.html}, eprint = {https://eej.aut.ac.ir/article_819_3b80c600439d87bf71029a9ede71749c.pdf} } @article { author = {Karami, E. and Madrigal, M. and Gharehpetian, G. B.}, title = {Dynamic Harmonic Modeling and Analysis of VSC-HVDC Systems}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {31-38}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.816}, abstract = {Harmonics have become an important issue in modern power systems. The widespread penetration of non-linear loads to emerging power systems has turned power quality analysis into an important operation issue under both steady state and transient conditions. This paper employs a Dynamic Harmonic Domain (DHD) based framework for dynamic harmonic analysis of VSC-HVDC systems. These systems are widely used in modern power systems in both distribution and transmission levels in order to provide voltage profile improvement, power flow control and power loss reduction. In this paper, appropriate modeling of VSC-HVDC systems for harmonic propagation is performed by means of switching function which provides a connection between DC and AC sides. Also in this paper, dynamics related to DC side capacitor are taken into account which can greatly affect the transient response. In order to validate the results, the proposed method has been successfully tested on a test system and the obtained results are compared to those of a time-domain software, followed by discussion on results.}, keywords = {VSC-HVDC,Dynamic Harmonic Domain,Power Quality,Steady State Response,Switching Function}, url = {https://eej.aut.ac.ir/article_816.html}, eprint = {https://eej.aut.ac.ir/article_816_7b1a184c931073f03cfe72678ba079c0.pdf} } @article { author = {Aazami, R. and Talaeizadeh, V. and Daniar, S.}, title = {Transmission switching cost modeling and determination candidate Lines for participation in joint energy and reserve markets}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {39-52}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.815}, abstract = {There is a great resolution calling for smart grids in recent years. Introduction of new technologies, that make the network flexible and controllable, is a main part of smart grid concept and a key factor to its success. Transmission network as a part of system network has drawn less attention. Transmission switching as a transmission service can release us from load shedding and remove the constraints’ violations.In addition to removing the congestion and decreasing the system cost, transmission switching may damage generating units due to transient states in instance of reconfiguration. Therefore, in optimal transmission switching, the system security, practical limitations and possible damages should be considered.Considering dynamic constraints in proposed model avoid the occurrence of transient instability when opening the line in transmission switching action.A network reduction method based on modified Jacobean AC Newton-Raphson technique power flow considering switchable line in technique is used for speeding up the calculation, efficiency and simplicity. An approach for selecting the best lines in switching operation in the network is proposed. Based upon this approach, the lines with the highest effect on cost reduction are considered as the candidate switchable line.To investigate the efficiency of the proposed strategy IEEE 57 bus test system is studied.}, keywords = {smart grids,transmission switching,Security,day-ahead market}, url = {https://eej.aut.ac.ir/article_815.html}, eprint = {https://eej.aut.ac.ir/article_815_f20d4a6a3fa5ec0d70d631a452fd3f0e.pdf} } @article { author = {Molaei, A. M. and Sedaaghi, M. H. and Ebrahimnezhad, H.}, title = {Steganography Scheme Based on Reed-Muller Code with Improving Payload and Ability to Retrieval of Destroyed Data for Digital Images}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {53-62}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.814}, abstract = {In this paper, a new steganography scheme with high embedding payload and good visual quality is presented. Before embedding process, secret information is encoded as block using Reed-Muller error correction code. After data encoding and embedding into the low-order bits of host image, modulus function is used to increase visual quality of stego image. Since the proposed method is able to embed secret information into more significant bits of the image, it has improved embedding payload. The steps of extracting data from the host image are independent of the original image. Therefore, the proposed algorithm has a blind detection process which is more suitable for practical and online applications. The simulation results show that the proposed algorithm is also able to retrieve destroyed data by intentional or unintentional attacks such as addition of noise and filtering due to use of the error correction code. In addition, the payload is improved in comparison with the same techniques.}, keywords = {Blind Detection,High Payload,Low-Order Bits Embedding,Retrieval of Destroyed Data,Steganography}, url = {https://eej.aut.ac.ir/article_814.html}, eprint = {https://eej.aut.ac.ir/article_814_9a524b3c488a78834f73f7ad40c3a591.pdf} } @article { author = {Mohammadi, F. and Abdi, H. and Dehnavi, E.}, title = {Solving Multiple Fuels Dynamic Environmental/Economic Dispatch Problem and Incentive Based Demand Response Considering Spinning Reserve Requirements}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {63-74}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.813}, abstract = {In this paper a new integrated model of the dynamic environmental/economic dispatch (DEED) problem and emergency demand response program (EDRP) has been presented by which their interactions are investigated. DEED schedules the online generators power output over the whole dispatch period subject to some practical constraints so that the fuel costs and emission are optimized simultaneously. EDRP is one of the incentive-based demand response program in which incentives are paid to the customers to reduce their consumption during peak hours or shift it to the off-peak or valley hours. The proposed integrated model is a multi-objective optimization problem which aims to minimize both the fuel costs and emission and determine the optimal incentive of EDRP under some of practical constraint of units such as valve-point loading effect, multiple fuels, prohibited operating zones, and spinning reserve requirements. The proposed model has been applied on a ten generation units test system. The results indicate the effectiveness of the integrated model in reducing fuel costs and emission, improving load curve characteristics, spinning reserve, and consequently the network reliability.}, keywords = {Dynamic environmental/economic dispatch,Demand response,Optimal incentive,Multiple fuels,Spinning reserve requirements}, url = {https://eej.aut.ac.ir/article_813.html}, eprint = {https://eej.aut.ac.ir/article_813_75fb6c3511bcd61d3e1c5c890430dfa0.pdf} } @article { author = {Hokmabadi, A. and Keshtkar, A. and Bayat, A. and Keshtkar, A.}, title = {A Miniaturized CPW-Fed Tapered Slot Antenna in Lossy Environment for UWB Application in Breast Cancer Detection}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {75-84}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.11846.5008}, abstract = {In this paper, a miniaturized coplanar waveguide fed (CPW-fed) tapered slot antenna (TSA) is introduced for breast cancer detection. Here, a modified CPW to slot-line transition structure with an air-bridge is employed to broaden the transition bandwidth and increase the radiation efficiency. Through these applied modifications, negative features of the original TSA (limitation of transition) and antipodal Vivaldi antenna (bad cross-polarization) are both removed, while all the positive features remained. We have developed a FDTD-UPML method in lossy environment by using Debye model. To validate the results, a prototype of the proposed antenna is fabricated and tested. By immersing the antenna in alcohol ethanol as a lossy coupling medium and inserting it close to a two-layer breast phantom, near-field parameters are calculated in different probe locations. Results show that the proposed structure offers a broad bandwidth of 0.5–19 GHz and also exhibits an appropriate current distribution with high radiation efficiency. Images of energy flux density (EFD) and fidelity factor (FF) confirm the good performance of the antenna in near-field region.}, keywords = {breast cancer detection,CPW-fed,microwave imaging,tapered slot antenna (TSA),Vivaldi}, url = {https://eej.aut.ac.ir/article_877.html}, eprint = {https://eej.aut.ac.ir/article_877_19489be3856e18f161aff9e1777681ad.pdf} } @article { author = {Mohammadi, L. and Amiri, S. and Mohammadkhani, G.R.}, title = {Evaluation of Geometric and Atmospheric Doppler for GNSS-RO Payloads}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {85-94}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2016.12054.5030}, abstract = {To reduce the sampling rate in global navigation satellite system (GNSS)-radio occultation receivers, it is essential to establish a suitable estimation of Doppler frequency from the received signal in the satellite onboard receiver. This receiver is usually located on low earth orbit satellite and receives GNSS satellites signal in the occultation situation. The occurred Doppler on the signal contains the Geometric and Atmospheric segments. The Geometric Doppler’s value depends on the orbital situation of transmitter and receiver. However, Atmospheric Doppler depends on the signal propagation environment conditions. To investigate the nature of these two types of Doppler, we establish different missions on STK software environment for receivers located on different orbits from 450km altitude to 800km and 1500km with different orbital parameters and by considering the Global Positioning System satellites as the transmitters. We also study the value and nature of the Atmospheric Doppler by utilizing and analyzing the data produced by the COSMIC Data Analysis and Archive Databases Center. In signal tracking part of the receiver, the variation of Doppler is also important, in addition to the Doppler that is called phase acceleration. Therefore, the derivatives of Geometric Doppler related to the LEO satellites in different altitudes need to be considered.}, keywords = {Atmospheric and Geometric Doppler,Open-loop tracking,radio occultation,Phase acceleration}, url = {https://eej.aut.ac.ir/article_878.html}, eprint = {https://eej.aut.ac.ir/article_878_4f93bfc0352a2a7e12c8cb620b3ca431.pdf} } @article { author = {Danaee, M. R. and Behnia, F.}, title = {Unscented Auxiliary Particle Filter Implementation of the Cardinalized Probability Hypothesis Density Filters}, journal = {AUT Journal of Electrical Engineering}, volume = {49}, number = {1}, pages = {95-106}, year = {2017}, publisher = {Amirkabir University of Technology}, issn = {2588-2910}, eissn = {2588-2929}, doi = {10.22060/eej.2017.12053.5029}, abstract = {The probability hypothesis density (PHD) filter suffers from lack of precise estimation of the expected number of targets. The Cardinalized PHD (CPHD) recursion, as a generalization of the PHD recursion, remedies this flaw and simultaneously propagates the intensity function and the posterior cardinality distribution. While there are a few new approaches to enhance the Sequential Monte Carlo (SMC) implementation of the PHD filter, current SMC implementation for the CPHD filter is limited to choose only state transition density as a proposal distribution. In this paper, we propose an auxiliary particle implementation of the CPHD filter by estimating the linear functionals in the elementary symmetric functions based on the unscented transform (UT). Numerical simulation results indicate that our proposed algorithm out performs both the SMC-CPHD filter and the auxiliary particle implementation of the PHD filter in difficult situations with high clutter. We also compare our proposed algorithm with its counterparts in terms of other metrics, such as run times and sensitivity to new target appearance.}, keywords = {Multi-target tracking,Cardinalized probability hypothesis density filter,unscented auxiliary particle filter,linear functional,potential functions}, url = {https://eej.aut.ac.ir/article_912.html}, eprint = {https://eej.aut.ac.ir/article_912_dc40c34768b9be09760b253281112d70.pdf} }