South Khorasan, Iran

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Shojaee S.,Shahid Bahonar University of Kerman | Mohammadian M.,Islamic Azad University at Ferdows
Structural and Multidisciplinary Optimization | Year: 2011

In this paper, we combine a Piecewise Constant Level Set (PCLS) method with a MBO scheme to solve a structural shape and topology optimization problem. The geometrical boundary of structure is represented implicitly by the discontinuities of PCLS functions. Compared with the classical level set method (LSM) for solving Hamilton-Jacobi partial differential equation (H-J PDE) we don't need to solve H-J PDE, thus it is free of the CFL condition and the reinitialization scheme. For solving optimization problem under some constraints, Additive Operator Splitting (AOS) and Multiplicative Operator Splitting (MOS) schemes will be used. To increase the convergency speed and the efficiency of PCLS method we combine this approach with MBO scheme. Advantages and disadvantages are discussed by solving some examples of 2D structural topology optimization problems. © 2011 Springer-Verlag.


Mohamadian M.,Islamic Azad University at Ferdows | Shojaee S.,Shahid Bahonar University of Kerman
International Journal for Numerical Methods in Engineering | Year: 2012

In this paper, we use binary level set method and Merriman-Bence-Osher scheme for solving structural shape and topology optimization problems. In the binary level set method, the level set function can only take 1 and -1 values at convergence. Thus, it is related to phasefield methods. There is no need to solve the Hamilton-Jacobi equation so it is free of the CFL condition and the reinitialization scheme. This favorable property leads to the great time advantage of this method. We use additive operator splitting (AOS) and multiplicative operator splitting (MOS) schemes for solving optimization problems under some constraints In this work, we also combine the binary level set method with the Merriman-Bence-Osher scheme. The combined scheme is much more efficient than the conventional binary level set method. Several two-dimensional examples are presented which demonstrate the effectiveness and robustness of proposed method. © 2011 John Wiley & Sons, Ltd.


Amini M.M.,Islamic Azad University at Ferdows | Motlagh M.R.J.,Iran University of Science and Technology
Proceedings - 2011 2nd International Conference on Control, Instrumentation and Automation, ICCIA 2011 | Year: 2012

In this paper the new one-degree and two-degree of freedom H ∞ loop shaping robust controllers are designed for a seeker scan loop, which has model uncertainty and subjects to external & internal disturbances. Both one-degree and two-degree of freedom H∞ loop shaping are constructed of two main stages; first, the nominal plant is dynamically diagonalized and shaped by pre- and post-compensators to give a desired shape to the singular values of the open loop frequency response and then shaped plant robustly stabilized with respect to coprime factor uncertainty using simple H∞ optimization and γ-iteration for one-degree of freedom H∞ loop shaping and two-degree of freedom H∞ loop shaping respectively. Finally, designed controllers are applied to the plant and simulation results in time and frequency domains such as step response, external and process disturbances rejection, robust performance and scan performance are shown and compared for these controllers and some other works. © 2011 IEEE.


Amini M.M.,Islamic Azad University at Ferdows | Motlagh M.R.J.,Iran University of Science and Technology
Proceedings - 2011 2nd International Conference on Control, Instrumentation and Automation, ICCIA 2011 | Year: 2012

In this paper an optimal robust controller, in terms of structured singular value- μ minimizing is designed for spin stabilized seeker, for achieving proper robust stability and robust performance with respect to the multiplicative input diagonal uncertainty. This optimal robust control can be designed using DK-iteration. This optimality involves solving a sequence of scaled H∞ problems. We do the DK-iteration up to 3, to show the number of iteration effects in stability and performance quality of the synthesized control systems. Finally, designed controllers are applied to the plant and simulation results in time and frequency domains such as; step response, external and process disturbances rejection, robust performance and scan performance are shown and compared for these controllers and some other works. © 2011 IEEE.


Samadi R.,Islamic Azad University at Ferdows | Hamidzadeh J.,Sadjad University of Technology
2014 International Congress on Technology, Communication and Knowledge, ICTCK 2014 | Year: 2015

The dynamic economic dispatch (DED) problem is an extension of the conventional static load dispatch problem in the context of electrical power generation. In this paper, issues related to the implementation of the several soft computing techniques are highlighted for a successful application to solve dynamic economic dispatch (DED) problem, which is a constrained optimization problem in power systems. First of all, a survey covering the basics of the techniques is presented and then implementation of the techniques in the DED problem is discussed. The soft computing techniques, namely multi-layered perceptron neural network (MLP NN), genetic algorithm (GA), Imperialist Competitive Algorithm(ICA), particle swarm (PSO) and are applied to solve the DED problem. The Evolutionary Algorithms are tested on power system consisting 3 generating units and the results are compared together. Suggestion is presented to improve techniques. © 2014 IEEE.


Mirzaei S.M.,Islamic Azad University at Ferdows | Moattar M.H.,Islamic Azad University at Mashhad
International Journal of Electrical and Computer Engineering | Year: 2015

Fish robot precision depends on a variety of factors including the precision of motion sensors, mobility of links, elasticity of fish robot actuators system, and the precision of controllers. Among these factors, precision and efficiency of controllers play a key role in fish robot precision. In the present paper, a robot fish has been designed with dynamics and swimming mechanism of a real fish. According to equations of motion, this fish robot is designed with 3 hinged links. Subsequently, its control system was defined based on the same equations. In this paper, an approach is suggested to control fish robot trajectory using optimized PID controller through Bacterial Foraging algorithm, so as to adjust the gains. Then, this controller is compared to the powerful Fuzzy controller and optimized PID controller through PSO algorithm when applying step and sine inputs. The research findings revealed that optimized PID controller through Bacterial Foraging Algorithm had better performance than other approaches in terms of decreasing of the settling time, reduction of the maximum overshoot and desired steady state error in response to step input. Efficiency of the suggested method has been analyzed by MATLAB software. © 2015 Institute of Advanced Engineering and Science. All rights reserved.


Es'haghi Z.,Payame Noor University | Mohtaji M.,Islamic Azad University at Mashhad | Hasanzade-Meidani M.,Islamic Azad University at Mashhad | Hasanzade-Meidani M.,Islamic Azad University at Ferdows | Masrournia M.,Islamic Azad University at Mashhad
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2010

New pre-concentration technique, triple phase suspended droplet microextraction (SD-LPME) and liquid chromatography-photodiode array detection was applied to determine ecstasy, MDMA (3,4-methylendioxy-N-methylamphetamine) in hair samples. In this research MDMA in hair was digested and after treatment extracted. The effective parameters were investigated and method was evaluated. Under the optimal conditions, the MDMA was enriched by factor 98.11. Linearity (r = 0.9921), was obtained in the range of 10-15,000 ng mL-1 and detection limit was 0.1 ng mL-1. © 2010 Elsevier B.V. All rights reserved.


Choobbasti A.J.,Babol Noshirvani University of Technology | Zahmatkesh A.,Islamic Azad University at Ferdows | Noorzad R.,Babol Noshirvani University of Technology
Geotechnical and Geological Engineering | Year: 2011

Stone columns (or granular piles) are increasingly being used for ground improvement. This study investigates the qualitative and quantitative improvement in soft clay by stone columns. Finite element analyses were carried out to evaluate the performance of stone columns in soft clay. A drained analysis was carried out using Mohr-Coulomb's criterion for soft clay, stones, and sand. The interface elements were used at the interface between the stone column and soft clay. Analyses and calculations were carried out to determine equivalent parameters of soil/columns system. The bearing capacity ratio (BCR) of the soil has been estimated for homogeneous and heterogeneous soil. The results have shown that the values of BCR for homogeneous soil are obviously higher than those for heterogeneous soil. © 2011 Springer Science+Business Media B.V.


Bijari M.K.,Islamic Azad University at Ferdows | Yazd H.G.H.,Islamic Azad University at Ferdows | Tavousi M.,Islamic Azad University at Ferdows
Journal of Materials and Environmental Science | Year: 2015

Groundwater has always been one of the major sources of drinking and agriculture especially in arid and semi-arid agriculture regions. BirjandAquifer in South Khorasan province, due to its location in the arid region, considers the use of groundwater as the most important and at the same time sole source of freshwater. Modeling and prediction of wells' hydrostatic level is one of the basic tasks to achieve the optimal management of water resources.The current article mainly aims to evaluate the effectiveness of artificial neural network technique and time series in the prediction of hydrostatic level of groundwater. For this purpose, the data on hydrostatic level of 13 piezometer wells present in Birjand plain as one of the sub-basins of Lut Desert was utilized in the 16-year statistical period of 1997-2013 on a monthly basis.In the current study, the discharge parameters including(amount of water extraction per cubic meter from drinking water wells, industry and agriculture), the water entering each polygon in terms of cubic meters (due to precipitationin the area) and water surface level (m) per piezometers in the previous time step were used, and the model output waswater level at the current time step.Wells' hydrostatic level was simulated separately by neural network technique and time series (SARIMA), and finally RMSE, MAE and R2 were used to determine prediction accuracy of each of two methods. The study results indicated the high precision of both techniques of neural network and time series in the prediction of the hydrostatic level of the wells in the region.


Zahmatkesh A.,Babol Noshirvani University of Technology | Zahmatkesh A.,Islamic Azad University at Ferdows | Choobbasti A.J.,Babol Noshirvani University of Technology
Arabian Journal of Geosciences | Year: 2015

A study to illustrate the ground surface and wall movements due to excavation is undertaken based on two-dimensional nonlinear finite element (FE) modeling and analysis. The FE model and nonlinear solution strategy are built in the open-source software platform, OpenSees, of the Pacific Earthquake Engineering Research Center. A drained analysis was carried out using Drucker–Prager multisurface kinematic plasticity model for sand. The proposed model is verified using a case history in an urban excavation. The ground surface settlement and wall deflection for the various conditions of excavation are calculated. The results indicate that the extent of the settlement zone depends on excavation depth and is predicted as 2.5–3 times excavation depth, and the upper limit of the maximum ground surface settlement is equal to the maximum lateral wall deflection. © 2014, Saudi Society for Geosciences.

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