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Showing 16 results for Hossein
Mr Hamed Nosrati, Dr Mousa Shamsi, Mr Motreza Farhid, Dr Mohammad Hossein Sedaaghi, Volume 1, Issue 1 (9-2013)
Abstract
Wireless Sensors and wireless sensor networks have been used broadly in academic communities. That is owing to increasingly development of small scale equipment in engineering that prepares enormous applications. Numerous researches have been done in order to using of these sensors as well as establishing them as a network and large variety of solutions have been suggested. One heuristic method to modeling wireless sensor networks is distributed adaptive modeling. Processing is done in fully distributed manner at this way. An adaptive network contains a number of nodes those are capable to learn and adapt. Every node exchanges its data with neighbor nodes so as to the network could finally solve an estimation or interference problem. In this paper, at first, the position of distributed adaptive processing will be explained, then we review some proposed strategies for adaptive modeling and after that simulation results will be compared.
Mr. Majid Hosseinpour, Dr Mustafa Mohamadian, Dr Ali Yazdian Varjani, Volume 1, Issue 2 (1-2014)
Abstract
In this paper, the performance of wireless operation of four-leg parallel inverters, at the presence of unbalanced nonlinear loads, is investigated. In order to control the parallel inverters, an inner current and external voltage control loops should be designed. In this paper, a proportional controller for the current internal loop as well as a proportional-resonant one for the voltage external loop are investigated and designed to ensure the proper performance of the system at the presence of unbalanced and nonlinear loads. In this paper, droop control and virtual output impedance loops have formed the power sharing control system for the parallel inverters. The proposed system is able to feed balanced, unbalanced, and nonlinear loads and provides an appropriate sinusoidal voltage waveform for loads by accurately sharing power between the parallel inverters. Simulation results verify the accurate and proper performance of the proposed system.
Mr. Saeid Mansouri, Dr. Hossein Ebrahimnezhad, Volume 2, Issue 2 (1-2015)
Abstract
3D surface compression is a selected method for reduction of required memory and effective triangular mesh data transfer in networks with low bandwidth. In this paper, an improved technique for compression of triangular surfaces is introduced. It is based on centroidal Voronoi tessellation with density function. By choosing appropriate density function with curvature feature and Lloyd relaxation, vertex density in compressed mesh tends toward details in rough surfaces and prevents vertex redundancy and non-necessary vertex concentration in smoother surface areas. In post-processing step, non-linear Nelder-Mead optimization is applied for better vertex localization and reducing compression error in the simplified mesh. Our proposed method is compared with classic and modern techniques in recent studies. Implementation results show improvements in compression and accuracy of our method compared with available techniques.
Eng. Faranak Shamsafar, Prof. Hossein Ebrahimnezhad, Volume 5, Issue 1 (Vol.5, No.1 2019)
Abstract
3D human pose estimation is one of the most significant tasks in computer vision with wide range of applications. The works for estimating human pose initialized from 2D skeletal estimation from multiple data and has proceeded toward 3D skeletal estimation from minimum input information. In this paper, 3D human pose estimation from a single RGB image is investigated. The proposed work is considered as the ones which firstly estimate 2D pose and then lift the estimated 2D configuration to 3D space. Since most of the errors in this attitude are originated by inaccurate 2D pose inference, we have proposed a method for predicting more accurate 2D poses to obtain 3D poses with less errors. The proposed approach for estimating 2D pose has leveraged deep learning along with the information of the edge map. In other words, we have made use of edge features, which are hand-designed features, in order to guide the deep neural network in training and in learning the features in accordance with the defined objective. Experimental results have demonstrated less errors in 2D and consequently 3D pose estimation in Human3.6M and HumanEva-I benchmarks.
Mr. Amirreza Amirfathiyan, Dr. Hossein Ebrahimnezhad, Volume 6, Issue 1 (1-2020)
Abstract
Human facial generation of example image is used as a requirement for biometric applications for the purpose of identifying individuals. In this paper, face generation consists of three main steps. In the first step, detection of significant lines and edges of the example image are carried out using nonlinear grayscale morphology. Then, hair areas are identified from the face of sample. The final step combines images from previous steps. Similarity and matching between synthesized face sketch and artistic sketch are compared with two methods of extracting features, Principle Component Analysis and Linear Discriminant Analysis, and time of the process is calculated. The experiments on the pair of CUHK database images show that the proposed method compared with state of the art methods such as: Eigen transformation, LLE, and MRF, has no computational complexity and creates a person's face with good quality and much less time. Matching of synthesized face sketch of the proposed method is achieved with a maximum value of 90% when Linear Discriminant Analysis is used to extract feature. The proposed method is also resistant to background effects and brightness of example images.
Mr Mohammad Javad Amoshahy, Dr Mousa Shamsi, Dr Mohammad Hossein Sedaaghi, Volume 6, Issue 1 (1-2020)
Abstract
The particle swarm optimizer (PSO) is a population-based metaheuristic optimization method that can be applied to a wide range of problems but it has the drawbacks like it easily falls into local optima and suffers from slow convergence in the later stages. In order to solve these problems, improved PSO (IPSO) variants, have been proposed. To bring about a balance between the exploration and exploitation characteristics of PSO, this paper introduces computationally fast and efficient IPSO algorithms based on a novel class of exponential learning factors (ELF-PSO). This class contains time-varying exponential learning factors (TELF), random exponential learning factors (RELF), self-adjusting exponential learning factors (SELF) and linear-exponential learning factors (LELF) strategies. Experiment is performed and compared with a set of well-known constant, random, time-varying and adaptive learning factors strategies on a suite of nonlinear benchmark functions. The experimental results and statistical analysis prove that ELF-PSO algorithms are able to solve a wide range of difficult nonlinear optimization problems efficiently. Also these results show that the proposed methods outperform other algorithms in most cases.
Ms. Khadijeh Mahdikhanlou, Dr. Hossein Ebrahimnezhad, Volume 7, Issue 1 (9-2020)
Abstract
Sign language recognition systems help deaf people to access various media. In this paper, the Leap Motion Controller (LMC) and the image of the hand are exploited for sign language recognition. The LMC provides 3D position of the hand joints. The first set of features are extracted from the data provided by the LMC. When the hand is not located in vertical view of the LMC or when the hand posed like a fist, the precise position of the hand joints is not recognizable. The second feature extracted from hand image helps most hand gestures be recognized precisely. The second feature includes histogram of oriented gradients and the distance of the hand contour form the center of the hand. Also, a dataset composed of variant American sign language gestures is created which includes 64000 samples. In recognition stage, random forest is applied which is a good option for large datasets. The experimental results show that the proposed method performs better than similar methods.
Zahra Bounik, Dr Mousa Shamsi, Dr Mohammad Hossein Sedaaghi, Volume 7, Issue 1 (9-2020)
Abstract
In this paper, a real-time interactive high resolution soft tissue modeling is implemented that enriches a coarse model in a data-driven approach to produce a fine model. As a preprocess step, a set of corresponding coarse and fine models are simulated for the database. In the test step, by using a regressor, the coarse model in the test set is compared to the coarse models in the training set and the blending weights are assigned to the training coarse models. These weights are used for approximating the fine model as a linear combination of the corresponding fine models in the train set. To decrease the computational complexity, assuming that applying a force on the tissue results in a local deformation, a feature extraction algorithm is proposed that considers the displacements of the contact node and its neighbor nodes and ignores the rest. This results in a low dimensional feature vector and decreases the computational complexity. In order to compute the blending weights, a nonlinear regressor with Gaussian kernel is leveraged. To eliminate the artefacts resulting from negative weights, a nonnegative least square algorithm is used for regression. Simulation results of applying the proposed method on two soft tissue models are investigated regarding the reconstruction accuracy, computational complexity and running time.
Dr. Said H. Esfahani, Mr. Hossein Akbari Ashiani, Volume 7, Issue 2 (3-2021)
Abstract
This paper is concerned with the problem of improvement of fuzzy H_infinity tracking controller for nonlinear systems modeled by T-S fuzzy scheme. The fuzzy tracking controller not only stabilizes the closed-loop system, but also results in the H_infinity tracking error norm to all the bounded external signals to be less than some given value. A new tracking control law is proposed for each linear local subsystem of T-S fuzzy model. A Linear Matrix Inequalities (LMIs) approach is proposed to find all the parameters of the control laws. The proposed approach results in a noticeable improved tracking performance with respect to the existing approaches. An investigation of the tracking performance of the proposed approach on the inverted pendulum system, in comparison with the other approaches, shows the improvement.
Ms. Lida Asgharian, Dr. Hossein Ebrahimnezhad, Volume 8, Issue 1 (9-2021)
Abstract
Nowadays, various kind of smart phones and 3D software are produced, which require large memory space. However, large number of vertices and faces in 3D models not only decrease the speed of sending and receiving of data but also can make problem in systems with low memory space. In this paper, an anisotropic re-meshing of 3D models is proposed. In this algorithm, the Nyquist theorem is employed for sampling from each selected segment of the mesh, locally. Then, the re-triangulation algorithm is applied to the selecte samples to construct the simplified mesh. In order to construct a high quality mesh from the remeshed model, a non linear subdivision is employed. The achieved results show that the algorithm can reduce the number of vertices and faces beside preserving details of model. The proposed method is also compared to the state-of-the-art algorithms are used in simplification studies, the outcomes illustrate the ability of the proposed method in producing high quality models.
Hossein Safaeipour, Mehdi Forouzanfar, Amin Ramezani, Volume 8, Issue 1 (9-2021)
Abstract
In chemical processes, thermal reactors are described by nonlinear closed-loop dynamic models. Timely detection of simultaneous fouling phenomena in the heat transfer system is a concern of this art. In this work, a new incipient fault diagnosis approach is proposed for application in the closed-loop non-isothermal continuous stirred-tank reactor (CSTR) system subjected to simultaneous Gaussian and non-Gaussian noises. First, the state vector is estimated by applying the well-known particle filter estimator. Then, the primary residual signal is generated using the system measurements, and the fault vector estimation is obtained. After that, by an adaptive either fixed threshold design applied in the online monitoring devised with the proposed evaluation technique, while the fault detectability is improved, the false detection problem is restricted to the system permitted number. Bank on, preventive maintenance scheduling also incipient fault trend prediction have become possible using the Gauss-Newton identification method. Finally, in order to evaluate the proposed approach, the simultaneous fouling incipient fault diagnosis over the heat transfer unit built-in nonlinear closed-loop CSTR system is considered. Furthermore, the confusion matrix and associated evaluation indices are employed to assess the simulation results quantitatively.
Amin Asghari, Ebrahimnezhad Hossein, Volume 8, Issue 2 (3-2022)
Abstract
Face plays an important role in visual communication. By looking at the face, it can be automatically extracted many non-verbal messages, such as identity, intention, and emotion. In computer vision, localization of the key points of the face is usually a key step for automatic extraction of face information, and many facial analysis techniques are built on the precise recognition of these embossed. Facial landmark detection and alignment in images with occlusion is a very important and challenging task in many visual and image processing tasks. In this paper, a comprehensive method for initialization and alignment of facial landmark through training of local binary features (LBP) and histogram orientated gradient (HOG) and a facial landmark detection method using robust cascade pose regression, which are specified as pixel difference features of landmarks, is introduced. At first, by analyzing the correlation of the local binary pattern histogram (LBP) and then by using histogram orientated gradient, the features of the training images are obtained. For the test image using these features the instructional images are estimated as optimal guide points. In the test stage, according to initialization of the image, the selection of the appropriate feature for the image is used to speed up the process, which means the number of steps to be chosen for each image is better. A strong cascade mode regression is then used to adjust the face, and a local principle is applied to learn the features of the guide points. The local principle helps to learn a set of highly distinctive binary features for the face guide points independently; these local binary features are used to jointly learn the cascade mode regression for the final output. The results show that the initialization used in this work has increased the accuracy of the estimation in the cascade state regression and has obtained better results than the random initialization.
Javad Mostafaee, Hossein Norouzi, Hassan Keshavarz Ziarani, Mansoor Hemmati, Volume 8, Issue 2 (3-2022)
Abstract
In this paper, a new adaptive controller based on the barrier function is designed for high-order nonlinear systems with uncertainties in mind. Accordingly, this paper uses a sliding mode controller that can simultaneously create asymptotic convergence and deal with perturbations. The main problems controlling the slip mode can be considered asymptotic convergence, umbrella phenomenon, stimulus saturation, control gain estimation and failure to deal with time-varying uncertainties. In this paper, the terminal slip mode controller is used to deal with the phenomenon of asymptotic convergence and umbrella and the barrier function is used to overcome the uncertainties of time variable. The advantages of the proposed method include the elimination of the Chattering phenomenon, convergence in finite time, compatibility with time-varying uncertainties, no use of estimates and no need for information on the high limit of perturbations. Stability analysis shows that in the proposed controller, the tracking errors approach the convergence region in the zero range and provide faster convergence. Finally, to prove the efficiency of the controller, based on the chaos synchronization theory, we apply the proposed controller to a new 5D hyperchaotic system. The results show that the proposed controller, despite the disturbances applied to the system, provides rapid convergence and eliminates the umbrella phenomenon.
Majid Hosseinpour, Tooraj Sabetfar, Volume 9, Issue 1 (9-2022)
Abstract
Polymer electrolyte membrane fuel cells (PEMFC) have been considered by researchers due to their high efficiency, low pollution, and high-power density in distributed generation systems. In this paper, the connected PEMFC fuel cell power recovery system with an LCL filter is evaluated in the harmonic Grid. LCL filters, despite their greater ability to attenuate harmonics, can lead to system resonance and instability. In this research, a transformer has been used to connect the fuel cell inverter to the Grid and its leakage inductance has been used as the inductor on the network side. Besides, for optimal resonance damping, and attenuation of current ripple caused by grids voltage harmonics, capacitor voltage through feedback control has been used. Complete control of capacitor voltage feedback includes proportional, derivative, and second-order components. In the proposed control scheme, the capacitor voltage derivative component opposes the capacitor current feedback due to identical and symmetrical loop gain. Therefore, both of them can be deleted. Thus, the capacitor current sensor is saved. Instead, the LCL filter resonance is damped by a proportional component and a second-order derivative of the capacitor voltage. A low-pass filter is also added to the second-order derivative in the controllable frequency range to ensure system stability. The simulation results of the PEMFC power recovery system in different conditions confirm the proper attenuation of the grid-connected inverter, the injection of current of suitable quality into the contaminated and harmonic grid, the stability, and the appropriate dynamic response of the proposed system.
Esmaeil Bahmani, Dr Mohsen Ahmadnia, Dr Hossein Sharifzadeh, Volume 9, Issue 2 (3-2023)
Abstract
Extracting maximum power, especially with partial shading conditions, is one of the most critical issues in using a photovoltaic system. Under partial shading conditions, the power-voltage characteristic of photovoltaic arrays has several local maximum points. A maximum power point tracking method for photovoltaic systems should enable fast and accurate tracking of the global maximum during partial shading conditions to minimize power losses and steady-state fluctuations. This research presents an algorithm for tracking the maximum power point in a photovoltaic system under partial shading conditions using the gray wolf optimization technique. The gray wolf algorithm is a new optimization method that overcomes limitations such as poor tracking, steady-state fluctuations, and undesirable transients in perturb and observe and particle swarm optimization techniques. The proposed algorithm based on the gray wolf optimization algorithm is implemented on a photovoltaic system in MATLAB software to prove its efficiency. The performance of the proposed design is compared with two maximum power point tracking techniques based on cuckoo search and particle swarm optimization. The simulation results show that the performance of the proposed maximum power point tracking technique is superior to the compared designs in terms of speed and steady-state stability of the response, so that it reduces the values of maximum overshoot, settling time, and sustained fluctuations up to 40.91%, 66.67% and 59.1% respectively.
Simin Hosseinzadeh, Dr Ramazan Havangi, Volume 10, Issue 1 (3-2023)
Abstract
Disturbance and uncertaities exist in industrial systems and greatly affect the performance and stability of these systems. The robotic manipulator is one the most widely used devices in the industry that is highly affected by various disturbances. Hence establishing a proper control algorithm to estimate and eliminate disturbances seems crucial. Since the robotic manipulator is a highly nonlinear system, we need to design a nonlinear disturbance observer. In this thesis a nonlinear disturbance observer is proposed to estimate the constant and oscillatory disturbances in the studied system. On the other hand, since proportional-derivative controllers (PD) are widely used in industrial systems, so in this thesis, a suitable proportional derivative controller will be designed. This controller is not capable of dealing with disturbances and uncertainties, so a new supervisory controller structure has been proposed to estimate disturbances and stabilize the system. The core of proposed controller uses a new sliding model controller. Finally, some comparisions with PD and super twisting sliding mode controllers have been performed in several cases and the numerical results show the advantages of the proposed controller.
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