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Showing 135 results for Ali

M. Haghpanahi, H. Pirali ,
Volume 17, Issue 3 (IJES 2006)
Abstract

Finite element analysis of a tubular T-joint subjected to various loading conditions including pure axial loading, pure in-plane bending (IPB) and different ratios of axial loading to in-plane bending loading has been carried out. This effort has been established to estimate magnitudes of the peak hot spot stresses (HSS) at the brace/chord intersection and to find the corresponding locations as well, since, in reality, offshore tubular structures are subjected to combined loading, and hence fatigue life of these structures is affected by combined loading. Therefore in this paper, at the first step, stress concentration factors (SCFs) for pure axial loading and in-plane bending loading are calculated using different parametric equations and finite element method (FEM). At the next step, the peak HSS distributions around the brace/chord intersection are presented and verified by the results obtained from the API RP2A Code procedure. Also the locations of the peak hot spot stresses which are the critical points in fatigue life assessment have been predicted. 


A. Shidfar, Ali Zakeri,
Volume 17, Issue 4 (IJES 2006)
Abstract

This paper considers a linear one dimensional inverse heat conduction problem with non constant thermal diffusivity and two unknown terms in a heated bar with unit length. By using the WKB method, the heat flux at the end of boundary and initial temperature will be approximated, numerically. By choosing a suitable parameter in WKB method the ill-posedness of solution will be improved. Finally, a numerical example will be presented.


M.r. Alirezaee, S.a Mir-Hassani,
Volume 17, Issue 4 (IJES 2006)
Abstract

In the evaluation of non-efficient units by Data Envelopment Analysis (DEA) referenced Decision Making Units (DMU’s) have an important role. Unfortunately DMU’s with extra ordinary output can lead to a monopoly in a reference set, the fact called abnormality due to the outliers' data. In this paper, we introduce a DEA model for evaluating DMU’s under this circumstance. The layer model can result in a ranking for DMU’s and obtain an improving strategy leading to a better layer.


M. Nadjafikhah, H. R. Salimi Moghaddam ,
Volume 17, Issue 4 (IJES 2006)
Abstract

In this article, we generalize the concept of the Lie algebra of vector fields to the set of smooth sections of a T-bundle which is by definition a canonical generalization of the concept of a tangent bundle. We define a Lie bracket multiplication on this set so that it becomes a Lie algebra. In the particular case of tangent bundles this Lie algebra coincides with the Lie algebra of vector fields.


M. Haji-Ramazanali , M. Shafiee ,
Volume 18, Issue 2 (International Journal of Engineering 2007)
Abstract

  

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Abstract: Existence and uniqueness of solution for singular 2-D systems depends on regularity condition. Simple regularity implies regularity and under this assumption, the generalized wave model (GWM) is introduced to cast singular 2-D system of equations as a family of non-singular 1-D models with variable structure.These index dependent models, along with a set of boundary constraint relations, forming the admissible subspace, led to the recursive solution of the GWM.

 


H. Ahmadian, S. Nazari , H. Jalali ,
Volume 18, Issue 4 (International Journal of Engineering 2007)
Abstract

Abstract: The governing equations of motion for a drill string considering coupling between axial, lateral and torsional vibrations are obtained using a Lagrangian approach. The result leads to a set of non-linear equations with time varying coefficients. A fully coupled model for axial, lateral, and torsional vibrations of drill strings is presented. The bit/formation interactions are assumed to be related to the following parameters: bit motion, effects of gyroscopic moments, contact with the borehole wall, axial excitation due to bit/formation interactions, and hydrodynamic damping due to the presence of drilling mud. Simulation results show that parametric resonance and whirling may occur simultaneously within the range of operating conditions of drilling. The contact force between collar and borehole wall is calculated and its behavior is investigated. The dynamic behavior is quite complicated and may become non-periodic, suggesting a chaotic behavior.

  


Ali Yaran,
Volume 18, Issue 6 (International Journal of Engineering science 2007)
Abstract

This paper will promote many questions about the design validity of these exciting blocks. The physical design of these blocks is prone to have social and economical problems, and it is part of the visual pollution and disturbance created on the sky line of Scottish cities special Glasgow. This paper focuses on the necessity to establish a source of initial design for high rise housing design problem classes theory. A thorough research of all the estates in Glasgow area was launched. Thus, a high amount of information was classified, in an attempt to establish a theoretical approach to support the evaluation and appraisal of current blocks problems. The new class's theory in high rise housing design problems is used as a vehicle for conducting this paper analysis. Classification includes physical and social design problems domains. The physical problems domain variables of the numbers of stories, dwellings, entrances, type of corridor, access from the streets and sharing of the site. Furthermore, to the social problems domain variables of graffiti, damage, litter, crime, drugs, child density and health have been examined. Moreover, their interdependent relationships were explored throughout the new classes' theory. The study of the new classes, theory may prove to be extremely vital for future direction in adapting some from of urban design problem solving techniques. It also serves as an evaluation tool for housing design appraisal in the city from Glasgow and similar cities worldwide.
A. Seifoddin, H.a. Salimi , A. Seyed Esfahani ,
Volume 19, Issue 1 (International Journal of Engineering 2008)
Abstract

Abstract: Innovations, commercialized by new or old established firms, located at the core of industrial renewal process. The innovation concept has suffered transformations, along with the evolution of the models that try to explain and understand the innovation process. The innovative process corresponds to all activities that generate technological changes and the dynamic interaction between them, not necessarily being novelties. Linier model, Chain-Linked Model and National Innovation Systems (NIS) Approach, are three models that have developed for innovation process. Innovation process can be viewed as evolutionary process. One can recognize some mechanism for innovation evolution. These are grouped into two classes those that increase configurations variation and those that decrease it. Emergence of knowledge, knowledge flow and recombination are the mechanism to increase variation of configuration. Internal and external selections are the mechanism to selecting. Innovation operators are evolutionary operators that create new combinations of configuration and increase variation. This paper develops an evolutionary cycle in innovation process and extends evolutionary mechanisms of innovation.

  


.a. Seifoddin, M. H. Salimi , M. M. Syed Esfahani,
Volume 19, Issue 1 (International Journal of Engineering 2008)
Abstract

Innovations, commercialized by new or old established firms, located at the core of industrial renewal process. The innovation concept has suffered transformations, along with the evolution of the models that try to explain and understand the innovation process. The innovative process corresponds to all activities that generate technological changes and the dynamic interaction between them, not necessarily being novelties. Linier model, Chain-Linked Model and National Innovation Systems (NIS) Approach, are three models that have developed for innovation process. Innovation process can be viewed as evolutionary process. One can recognize some mechanism for innovation evolution. These are grouped into two classes those that increase configurations variation and those that decrease it. Emergence of knowledge, knowledge flow and recombination are the mechanism to increase variation of configuration. Internal and external selections are the mechanism to selecting. Innovation operators are evolutionary operators that create new combinations of configuration and increase variation. This paper develops an evolutionary cycle in innovation process and extends evolutionary mechanisms of innovation.


R. Sadeghian, G.r. Jalali-Naini, J. Sadjadi, N. Hamidi Fard ,
Volume 19, Issue 4 (IJIE 2008)
Abstract

  In this paper Semi-Markov models are used to forecast the triple dimensions of next earthquake occurrences. Each earthquake can be investigated in three dimensions including temporal, spatial and magnitude. Semi-Markov models can be used for earthquake forecasting in each arbitrary area and each area can be divided into several zones. In Semi-Markov models each zone can be considered as a state of proposed Semi-Markov model. At first proposed Semi-Markov model is explained to forecast the three mentioned dimensions of next earthquake occurrences. Next, a zoning method is introduced and several algorithms for the validation of the proposed method are also described to obtain the errors of this method.


Mohammad Ali Rezvani ,
Volume 19, Issue 5 (IJES 2008)
Abstract

It is the purpose of this paper to introduce a computer software that is developed for the analysis of general multi degree of freedom rotor bearing systems with non-linear support elements. A numerical-analytical method for the prediction of steady state periodic response of large order nonlinear rotor dynamic systems is addressed which is based on the harmonic balance technique. By utilizing harmonic balance with appropriate condensation, it is possible to considerably reduce the number of simultaneous nonlinear equations inherent to this approach. Using this method, the set of nonlinear differential equations governing the motion of the rotor systems is transformed to a set of nonlinear algebraic equations. A condensation technique is also used to reduce the nonlinear algebraic equations to those only related to the physical coordinates associated with nonlinear components. The stability (linear) of the equilibrium solutions may be conveniently evaluated using Floquet theory, particularly if the damper force components are evaluated in fixed, rather than rotating, reference frames. The versatility of this technique is illustrated on systems of increasing complexity with and without damper centralizing springs.


, , ,
Volume 20, Issue 1 (IJIEPR 2009)
Abstract

Fuzzy Cognitive Maps (FCMs) have successfully been applied in numerous domains to show the relations between essential components in complex systems. In this paper, a novel learning method is proposed to construct FCMs based on historical data and by using meta-heuristic: Genetic Algorithm (GA), Simulated Annealing (SA), and Tabu Search (TS). Implementation of the proposed method has demonstrated via real data of a purchase system in order to simulate the system’s behavior.
S.m. Mohammad Seyedhoseini , M. Ali Hatefi,
Volume 20, Issue 1 (IJIEPR 2009)
Abstract

  Selecting an effective project plan is a significant area in the project management. The present paper introduces a technique to identify the project plan efficient frontier for assessing the alternative project plans and selecting the best plan. The efficient frontier includes two criteria: the project cost and the project time. Besides, the paper presents a scheme to incorporate Directed Acyclic Graph (DAG) into the project risk analysis.

This scheme is used to estimate the expected impacts of the occurrence of the project risks on the project cost and the project time. Also, a theoretical model is defined to provide integration between project risk analysis and overall project planning using the breakdown structures. We believe that applying the proposed technique helps the company’s managers in most effective manner dealing with his complicated project plan assessment and selection problems. The application of the technique was implemented in the companies in construction industry in which represented a considerable cost and time improvements.
S. G. Jalali Naini , M. B. Aryanezhad, A. Jabbarzadeh , H. Babaei ,
Volume 20, Issue 3 (IJIEPR 2009)
Abstract

This paper studies a maintenance policy for a system composed of two components, which are subject to continuous deterioration and consequently stochastic failure. The failure of each component results in the failure of the system. The components are inspected periodically and their deterioration degrees are monitored. The components can be maintained using different maintenance actions (repair or replacement) with different costs. Using stochastic regenerative properties of the system, a stochastic model is developed in order to analyze the deterioration process and a novel approach is presented that simultaneously determines the time between two successive inspection periods and the appropriate maintenance action for each of the components based on the observed degrees of deterioration. This approach considers different criteria like reliability and long-run expected cost of the system. A numerical example is provided in order to illustrate the implementation of the proposed approach.
Ali Habibi Badrabadi , Mohammad Jafar Tarokh,
Volume 20, Issue 3 (IJIEPR 2009)
Abstract

Service Oriented Enterprises (SOEs) are subject to constant change and variation. In this paper, the changes are considered from an economic perspective based on service culture notion. Once a change is implemented, the costs of some member services may increase, whereas the costs of some other services may reduce. We construct a game theoretic model trying to capture the possible conflicting interests of different parties in a SOE. Three incentive mechanisms are applied to the model. The first incentive mechanism shares the utility equally among the services involved in the change the second utility-sharing rule is based on the Nash’s bargaining solution, which accommodates the possible biased interdependencies inside the network and the third rule, based on the Harsanyi’s modified Shapley value, takes into account the possible coalition formation among the network parties. Since the three rules are analytically solvable, the principles of utility sharing can be implemented, for instance, as ex-ante contracts.
Reza Kazemzadeh, Ali Reaziat,
Volume 20, Issue 4 (IJIEPR 2010)
Abstract

  In today’s extremely competitive markets it is crucial for companies to strategically position their brands, products and services relative to their competitors. With the emerging trend in internationalization of companies especially SME’s and the growing use of the Internet with this regard, great amount of attention has been turned to effective involvement of the Internet channel in the marketing mix of the companies. This has introduced a new term of market space (the Web) versus the traditional battleground of marketplace in which companies compete with each other. The growth of presence in the market space has been exponential, both in general and within specific industries.

  Thus bringing to attention the importance of Web presence and that it is crucial for companies to strategically regard competition in market space. It is important to understand that positioning on the Net is very different and requires its own set of strategies as part of the new marketing paradigm. This study goes towards addressing the need to understand and measure the nature of positioning of company Web sites on the Internet. The aim of the study is to introduce a statistical technique to compare the positioning of Web sites, in and across industries.

  With this regard a group of Web sites from the home appliances manufacturing industry was selected and the technique of correspondence analysis was applied to produce maps which can be studied and interpreted.

The results indicated that either based on company strategies or accidentally, these Web sites are positioned differently and may follow or affect different marketing policies of their owners. At the end, the implications of this technique for management and how it can be used by new home appliance manufacturers or those who want to compare their sites with the ones of their competitors, in order to benchmark and/or revise their policies and strategies have been discussed .
Mohammad Ali Shafia, Arnoosh Shakeri,
Volume 20, Issue 4 (IJIEPR 2010)
Abstract

This paper aims at emphasizing the importance of establishing a Project Management (PM) system in Technology Transfer (TT) processes and developing a conceptual framework for it. TT is an important process in Technology Management affairs for all enterprises.  Most of the time, lack of a particular concentration on technical, commercial and legal aspects of TT process, leads to mismanagement of other aspects of transferring project, like Time and Project Integration. This situation may lead to failure and loss of many opportunities in transfer process. To overcome this problem, inputs, outputs and activities of a typical TT processes are identified and based on these components, a conceptual framework for managing this project & prevent the loss is developed using Project Management models and methodologies.
Mohammad Mahdavi Mazdeh, Ali Khan Nakhjavani , Abalfazl Zareei,
Volume 21, Issue 2 (IJIEPR 2010)
Abstract

  This paper deals with minimization of tardiness in single machine scheduling problem when each job has two different due-dates i.e. ordinary due-date and drop dead date. The drop dead date is the date in which jobs’ weights rise sharply or the customer cancels the order. A linear programming formulation is developed for the problem and since the problem is known to be NP-hard, three heuristic algorithms are designed for the problem based on Tabu search mechanism. Extensive numerical experiments were conducted to observe and compare the behavior of the algorithms in solving the problem..


Ali Habibi Badrabadi , Mohammad Jafar Tarokh,
Volume 21, Issue 4 (IJIEPR 2010)
Abstract

  Response time is one of the critical web service quality dimensions. It refers to how long it takes that a web service responds to request of a user. In order to manage the response time, pricing schemes can work as an efficient access control mechanism. In this paper, we study competition between two providers offering functionally same web services where there is a monopoly service provider. The monopoly offers a service that is complementary to their services. Each provider needs to decide a service level (L or H) and a corresponding price for the selected service level to meet the service level guarantee. We construct a Stackelberg game and benefit from queuing theory concept to propose a model that can examine strategic choices of the providers .


Mohammad Ali Farajian , Shahriar Mohammadi ,
Volume 21, Issue 4 (IJIEPR 2010)
Abstract

  The unprecedented growth of competition in the banking technology has raised the importance of retaining current customers and acquires new customers so that is important analyzing Customer behavior, which is base on bank databases. Analyzing bank databases for analyzing customer behavior is difficult since bank databases are multi-dimensional, comprised of monthly account records and daily transaction records. Few works have focused on analyzing of bank databases from the viewpoint of customer behavioral analyze. This study presents a new two-stage frame-work of customer behavior analysis that integrated a K-means algorithm and Apriori association rule inducer. The K-means algorithm was used to identify groups of customers based on recency, frequency, monetary behavioral scoring predicators it also divides customers into three major profitable groups of customers. Apriori association rule inducer was used to characterize the groups of customers by creating customer profiles. Identifying customers by a customer behavior analysis model is helpful characteristics of customer and facilitates marketing strategy development .



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