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Nilashi M.,University of Technology Malaysia | Bagherifard K.,Islamic Azad University at Yasuj | Ibrahim O.,University of Technology Malaysia | Janahmadi N.,Ahrar Institute of Technology and Higher Education | Ebrahimi L.,Payame Noor University
Research Journal of Applied Sciences, Engineering and Technology | Year: 2012

The growing use of Internet in Malaysia provides a developing prospect of online shopping for international students. Also, international students are an outstanding group in online shopping in Malaysia. In view of this, in order to improve increase online shopping among international students and Malaysian online shopping, a research framework was proposed and a survey of international student was done. Proposed research framework considers three key dimensions service quality, information quality and system quality for online shopping website. To gather initial data, international students of UTM were asked. Data was collected from 300 international students of UTM. Using normal TOPSIS and fuzzy-TOPSIS approaches all parameters in hierarchy were ranked. Our findings demonstrated that using fuzzy-TOPSIS method trust, response time, reliability, responsiveness, empathy, timeliness, accuracy of information, navigation and accessibility are the nine first important parameters in online website quality. © Maxwell Scientific Organization, 2012.

Amirteimoori A.,Islamic Azad University at Rasht | Emrouznejad A.,Aston University | Khoshandam L.,Ahrar Institute of Technology and Higher Education
Measurement: Journal of the International Measurement Confederation | Year: 2013

Data envelopment analysis (DEA) has gained a wide range of applications in measuring comparative efficiency of decision making units (DMUs) with multiple incommensurate inputs and outputs. The standard DEA method requires that the status of all input and output variables be known exactly. However, in many real applications, the status of some measures is not clearly known as inputs or outputs. These measures are referred to as flexible measures. This paper proposes a flexible slacks-based measure (FSBM) of efficiency in which each flexible measure can play input role for some DMUs and output role for others to maximize the relative efficiency of the DMU under evaluation. Further, we will show that when an operational unit is efficient in a specific flexible measure, this measure can play both input and output roles for this unit. In this case, the optimal input/output designation for flexible measure is one that optimizes the efficiency of the artificial average unit. An application in assessing UK higher education institutions used to show the applicability of the proposed approach. © 2013 Elsevier Ltd. All rights reserved.

Mayeli P.,Ahrar Institute of Technology and Higher Education | Nili-Ahmadabadi M.,Isfahan University of Technology | Besharati-Foumani H.,Ahrar Institute of Technology and Higher Education
Numerical Heat Transfer, Part B: Fundamentals | Year: 2016

In this article, a novel iterative physical-based method is introduced for solving inverse heat conduction problems. The method extends the ball spine algorithm concept, originally developed for inverse fluid flow problems, to inverse heat conduction problems by employing a subtle physical-sense rule. The inverse problem is described as a heat source embedded within a solid medium with known temperature distribution. The object is to find a body configuration satisfying a prescribed heat flux originated from a heat source along the outer surface. Performance of the proposed method is evaluated by solving many 2-D inverse heat conduction problems in which known heat flux distribution along the unknown surface is directly related to the Biot number and surface temperature distribution arbitrarily determined by the user. Results show that the proposed method has a truly low computational cost accompanied with a high convergence rate. © 2016 Taylor & Francis Group, LLC.

Mayeli P.,Ahrar Institute of Technology and Higher Education | Nili-Ahmadabadi M.,Isfahan University of Technology | Pirzadeh M.,Ahrar Institute of Technology and Higher Education | Rahmani P.,Ahrar Institute of Technology and Higher Education
Computers and Fluids | Year: 2016

In the present study, numerical solution of an inverse conjugate heat transfer problem including conduction and forced convection is carried out via the ball spine algorithm (BSA). The BSA inverse method is originally developed for inverse shape design of pure fluid flow problems with a desired pressure distribution along an unknown surface but in this paper it is shown how proposing a novel remedy enables the BSA method of solving inverse heat transfer problems as well. The proposed method has a truly low computational cost accompanied by high convergence rate. The inverse problem is defined as heat source surrounded by a solid medium exposed to free stream in external flow. Heat is generated by a heat source and spreads all over the medium by conduction and then is transferred to free stream by forced convection. The objective is finding a configuration for the solid body to satisfy a prescribed uniform temperature along its surface. Solution of the mentioned inverse problem is dependent on different combinations of the dominant parameters including Reynolds number (Re), thermal conductivity ratio (kf /. ks ), desired outer surface temperature (θs ) and also Prandtl number (Pr). © 2016 Elsevier Ltd.

Rajabi H.,Islamic Azad University at Lahijan | Darvizeh A.,Islamic Azad University at Bandar Anzali | Shafiei A.,Ahrar Institute of Technology and Higher Education | Eshghi S.,Guilan University | Khaheshi A.,Guilan University
Journal of the Mechanical Behavior of Biomedical Materials | Year: 2014

At the first glance, mollusk shells may seem complex spatial structures with interesting shapes, forms and colors. However, from an engineering point of view, they are mechanical barriers which provide remarkable protection against environmental factors. These biological composites which exhibits an attractive combination of stiffness, strength and toughness, may be mimicked in bio-inspired materials. In the present work, a mathematical method is used to develop comprehensive three-dimensional (3D) numerical models of mollusk shells. The models are employed to study the mechanical behavior of the shells under static loading conditions. Numerical analyses are conducted using ANSYS finite element (FE) codes. A combination of indentation testing and scanning electron microscopy (SEM) is utilized to confirm the validity of the models and the solving procedures. A good agreement is observed between the shape, size and location of the failure obtained from experimental tests and numerical predictions. The results indicate that the columella increases the ability of mollusk shells to withstand applied mechanical forces without failure. Further, it can be concluded that the coiling geometry of the shells adequately modifies the stress distribution and reduces the stress concentration. © 2013 Elsevier Ltd.

Behnam B.,Islamic Azad University at Tabriz | Golpour F.,Ahrar Institute of Technology and Higher Education
International Journal of Applied Linguistics and English Literature | Year: 2014

In recent years, genre studies have attracted the attention of many researchers. The aim of the present study was to observe the differences in generic structure of abstract written by English native and non-native (Iranian) students in two disciplines of mathematics and applied linguistics. To this end, twenty native English students’ abstract texts from each discipline and the same number of non-native (Iranian) ones were selected. In this study, Hyland’s (2000) five‐move model was used to identify the rhetorical structure of the four sets of texts. After analyzing each text, the main moves were extracted and the frequencies of each one were calculated and compared. The cross-disciplinary and cross‐linguistic analyses reveal that linguistics abstracts follow a conventional scheme, but mathematics abstracts in these two languages do not exhibit the usual norms in terms of moves. Besides, greater difference in move structure is seen across languages in mathematics. The findings of the study have some pedagogical implications for academic writing courses for graduate students, especially students from non-English backgrounds in order to facilitate their successful acculturation into these disciplinary communities. © Australian International Academic Centre, Australia.

Sharifian A.,Ahrar Institute of Technology and Higher Education | Sasansara S.F.,Ahrar Institute of Technology and Higher Education | Balgori A.A.,Ahrar Institute of Technology and Higher Education
Neurocomputing | Year: 2016

Due to nonlinear behavior and the uncertainty with converter structure, controller design is difficult and accompanied with complexities. In this paper, a new control method based on Type-2 fuzzy neural PI (T2FN PI) controller is applied to improve the dynamic response of half-bridge DC–DC converters for different operation conditions. The T2FNN PI controller amends the specifications of the converter system by controlling its duty cycle of switching. In addition, proposed controller can property handle the uncertainty which is associated to converter structure, measuring devices and measured control signals. The T2FN PI controller is a combination of type-2 fuzzy linguistic process and neural network learning capability. The back-propagation algorithm is applied to train the parameters of T2FNN PI controller. Furthermore, PSO algorithm is applied to obtain the T2FN PI training pattern. In order to evaluate the performance of the proposed T2FN PI controller, it has been compared with a Fuzzy controller and the conventional PI controller for five different operating conditions. The simulation results show efficiency of the T2FNN PI controller in compare to Fuzzy controller and PI controller in terms of better rejection of disturbances, faster transient response and less peak overshoot. © 2016 Elsevier B.V.

Rajabi H.,Ahrar Institute of Technology and Higher Education | Darvizeh A.,Islamic Azad University at Bandar Anzali
Scientia Iranica | Year: 2014

A theoretical solution of the mechanical behavior of thick piezoelectric cylinders subjected to dynamic pressures is presented in this paper. The five governing equations in terms of resultant forces and resultant moments with respect to basic displacement vector components, and are used. The First-order Shear Deformation Theory (FSDT) is employed to consider the effects of shear forces on the shell structure. The effects of transverse shear deformation and rotary inertia are included into the analysis. The formulation is based on the thick-shell equations. Navier-type solutions are obtained and used for simply supported circular cylindrical shells. Finally, the Newmark family of methods is used to numerically time integration of the system of coupled second order ODEs. Results obtained with the present analysis are found to be in good agreement with those available in the literature. The results of this paper can serve as a reference for future study in the design of smart engineering structures. © 2014 Sharif University of Technology. All rights reserved.

Nasiri Shafti R.,Ahrar Institute of Technology and Higher Education | Ghasemi A.,K. N. Toosi University of Technology
ICEE 2012 - 20th Iranian Conference on Electrical Engineering | Year: 2012

Resource allocation is one of the major challenges in wireless communications including cognitive radio networks. In these networks secondary users try to coexist with primary ones. We consider a data communication scenario in which utility obtained by a user measures its quality of service (QoS). This utility is quantified based on success of the user for correct transmission of information bits. To provide primary users protection, a threshold tolerable interference is determined for them. Therefore, transmit powers of secondary users should be controlled in a way that the aggregate interferences for primary users are not exceeded from the predefined extent. A utility-based joint power and admission control (U-JPAC) algorithm is presented for data networks, in order to allocate radio resources in an efficient manner to the requesting links, while the interference constraints are not violated and considering the total utility of secondary users as the objective. Simulation results show that the proposed algorithm performs efficiently in maximizing total utility of cognitive data networks considering primary users protection compared to the similar previous algorithm. However, a small outage increment is occurring. It is illustrated by simulation results that U-JPAC algorithm is efficient in both single and multiple primary user scenarios. © 2012 IEEE.

Rajabi H.,Ahrar Institute of Technology and Higher Education | Monsef H.,Guilan University | Moghadami M.,Guilan University | Zare M.,Ahrar Institute of Technology and Higher Education | Armandei A.,Ahrar Institute of Technology and Higher Education
Ecotoxicology | Year: 2014

Since oil was first extracted, pollution of the seas and oceans or adjacent coasts has been an obstacle for the oil industry and environmental activists. The major concern is oil discharge into the water which may lead to birds' affliction or death, besides putting marine life in jeopardy. This paper presents the first description of the design and implementation of a new bird washing machine that can be utilized for cleaning of oil-coated birds with the minimum of stress. The machine is equipped with a pneumatic system comprised of 19 moving nozzles which evenly cover the bird's body and is designed to be used in contaminated environments where a vast number of birds are affected. Experimental trials show an improvement in operation efficiency compared to other methods in a reduction in washing time, energy consumption and a decrease in fatality rate of washed birds. © Springer Science+Business Media 2014.

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