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    Fuzzy queuing location-allocation models for congested systems

    , Article International Journal of Industrial Engineering : Theory Applications and Practice ; Volume 11, Issue 4 , 2004 , Pages 364-376 ; 10724761 (ISSN) Shavandi, H ; Mahlooji, H ; Sharif University of Technology
    University of Cincinnati  2004
    Abstract
    Since in the emergency service networks the length of time to attend a call is of utmost importance, it is imperative to observe guidelines in locating the service centers within a service network and allocating the demand nodes to them in a manner that service can be provided within a reasonably short period of time. So far both qualitative and quantitative models have been developed to tackle these problems. The latest models which assume a probabilistic orientation, use queuing theory notions to achieve a more suitable solution. This article attempts to apply both queuing theory and fuzzy theory to the location-allocation problem in hope of analyzing the problem in a more realistic... 

    Reconstruction in a generalized model for translation invariant systems [electronic resource]

    , Article Fuzzy Sets and Systems ; 1996, Volume 83, Issue 1, Pages 51–55 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    We consider translation invariant (TI) operators on Φ, the set of maps from an abelian group G to Ω ∪ {−∞} , called LG-fuzzy sets, where 0 is a complete lattice ordered group. By defining Minkowski and morphological operations on Φ and considering order preserving operators, we prove a reconstruction theorem. This theorem, which is called the Strong Reconstruction Theorem (SRT), is similar to the Convolution Theorem in the theory of linear and shift invariant systems and states that for an order preserving TI operator Y one can explicitly compute Y ( A ), for any A , from a specific subset of Φ called the base of Y . The introduced framework is a general model for the theory of translation... 

    Duality in a generalized model for translation invariant systems [electronic resource]

    , Article Fuzzy Sets and Systems ; 1996, Volume 83, Issue 3, Pages 347–352 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    In a previous paper we introduced a generalized model for translation invariant (TI) operators. In this model we considered the space, φ of all maps from an abelian group G to ω U {-∞}, called LG-fuzzy sets, where ω is a complete lattice-ordered group; and we defined TI operators on this space. Also, in that paper, we proved strong reconstruction theorem to show the consistency of this model. This theorem states that for an order-preserving TI operator Y one can explicitly compute Y(A), for any A, from a specific subset of φ called the base of Y. In this paper duality is considered in the same general framework, and in this regard, continuous TI operators are studied. This kind of operators... 

    A technical note on "A fuzzy set approach for R&D portfolio selection using a real options valuation model" by Wang and Hwang (2007)

    , Article Omega ; Volume 39, Issue 4 , 2011 , Pages 464-465 ; 03050483 (ISSN) Hassanzadeh, F ; Collan, M ; Modarres, M ; Sharif University of Technology
    2011
    Abstract
    In this paper, three critical issues with the paper "A fuzzy set approach for R&D portfolio selection using a real options valuation model", coauthored by Wang and Hwang and published in Omega 2007 are addressed. Shortcomings of the original work are highlighted and corrective measures to improve the approach are proposed  

    Fuzzy project scheduling with discounted cash flows

    , Article Economic Computation and Economic Cybernetics Studies and Research ; Volume 5 , 2012 ; 0424267X (ISSN) Shavandi, H ; Najafi, A. A ; Moslehirad, A ; Sharif University of Technology
    Abstract
    Project scheduling to maximize the net present value of the cash flows has been a topic of recent research. These researches assume that the duration of activities is known either with certitude or at least with some probability. However, in many applications the structure of the duration of activities is imprecise. In this paper, the project scheduling problem with discounted cash flows under fuzzy environment is considered. The duration of activities are assumed triangular fuzzy numbers. The derived mathematical model is a multi-objective non-linear programming model and for solving it the Taylor expansion is used to transform the objective function to a linear form. To interpret the fuzzy... 

    A new look on the automation of medium voltage substations in power distribution systems

    , Article 2012 Proceedings of 17th Conference on Electrical Power Distribution, EPDC 2012 ; 2012 ; 9781467314183 (ISBN) Shojaie, M ; Moghaddam, V.R ; Kazemi, A.A.R ; Dehghanian, P ; Karami, G ; Sharif University of Technology
    IEEE  2012
    Abstract
    With the expansion of electricity networks, increasing operational complexities, improved knowledge of the system operators, all with the subsidies elimination in some countries such as Iran and experiencing the real price of electricity by then, it necessitates a more reliable power to be delivered to the system customers. Power system automation is regarded as an efficient solution and the effective key to this problem. However, the great number of substations in power distribution systems has led to the fact that it is neither feasible nor economic to automate all of them. This calls for a comprehensive scheme on the placement of the distribution substations to be automated. In this... 

    A new extended analytical hierarchy process technique with incomplete intervalvalued information for risk assessment in IT outsourcing

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 30, Issue 5 , 2017 , Pages 739-748 ; 1728144X (ISSN) Ebrahimnejad, S ; Gitinavard, H ; Sohrabvandi, S ; Sharif University of Technology
    Abstract
    Information technology (IT) outsourcing has been recognized as a new methodology in many organizations. Yet making an appropriate decision with regard to selection and use of these methodologies may impose uncertainties and risks. Estimating the occurrence probability of risks and their impacts organizations goals may reduce their threats. In this study, an extended analytical hierarchical process method is tailored based on interval-valued hesitant fuzzy information to assess the risks in IT outsourcing. In the proposed approach, the weight of each decision maker is implemented in process of the proposed method by considering the concept of simple additive weighting method to decrease the... 

    Fuzzy economic dispatch and spinning reserve allocation using evolutionary programming

    , Article 40th North American Power Symposium, NAPS2008, Calgary, AB, 28 September 2009 through 30 September 2009 ; 2008 ; 9781424442836 (ISBN) Ahmadi Khatir, A ; Motamedi, A ; Sadati, N ; Fallahi, K ; Fathi, B ; Sharif University of Technology
    2008
    Abstract
    The objective of economic dispatch (ED) problem is minimizing the operating cost and finding the point where the total output of the generations equals the total power that must be delivered. In that point the incremental cost of power generation is also equal for all generators. Considering the presence of uncertainty and inaccuracy in the data, fuzzy set theory is an appropriate method to solve the economic dispatch problems. In this paper, a modified fuzzy economic dispatch is formulated to solve the problem under the competitive electricity market uncertainties. Also, available spinning reserve is optimally allocated to market participants. The formulated optimization problem it then... 

    Application of fuzzy set modeling in infrastructure visual impact assessment

    , Article 10th East Asia-Pacific Conference on Structural Engineering and Construction, EASEC 2010, Bangkok, 3 August 2006 through 5 August 2006 ; Volume 2 , 2006 , Pages 263-268 Vaziri, M ; Tolouei, R ; Namazi, S ; Sharif University of Technology
    2006
    Abstract
    Infrastructure visual impact assessment based on an opinion survey and fuzzy set modeling was attempted. Photographs reflecting various transportation infrastructure and environment features were displayed to a group of transportation professionals and users. The group was asked to complete a relevant questionnaire regarding the highway infrastructure appearance acceptability of photographs. A set of visual impact descriptive variables was identified and directly measured from the photographs. Information about the descriptive variables, questionnaire responses and fuzzy set theory was used to develop membership functions of visual acceptability. More than two hundred candidate membership... 

    Fuzzy hierarchical location-allocation models for congested systems [electronic resource]

    , Article Scientia Iranica ; January 2006, Scientia Iranica, Vol. 13, No. 1, pp. 14-24 Journal of Industrial and Systems Engineering ; 2007, Vol. 1 No. 2, pp 171-189 Shavandi, H. (Hassan) ; Mahlouji, Hashem ; Eshghi, Kourosh ; Khanmohammadi, S ; Sharif Universitty Of Technology
    Abstract
    There exist various service systems that have hierarchical structure. In hierarchical service networks, facilities at different levels provide different types of services. For example, in health care systems, general centers provide low-level services such as primary health care services, while the specialized hospitals provide high-level services. Because of demand congestion in service networks, location of servers and allocation of demand nodes have a strong impact on the length of queues at servers as well as on the response times to service calls. The thrust of this article is the development of hierarchical location-allocation models for congested systems by employing queueing theory... 

    A comprehensive framework for selecting the ERP system in Iran khodro company

    , Article European Journal of Economics, Finance and Administrative Sciences ; Issue 38 , October , 2011 , Pages 7-19 ; 14502275 (ISSN) Asgari, M ; Allahverdiloo, M ; Samkhani, S ; Sharif University of Technology
    2011
    Abstract
    Nowadays information technology has been applied in various fields. Enterprise Resource Planning (ERP) is one of the most important applications of IT in Iranian organizations. These systems can create competitive advantages for organizations. Companies which intend to use ERP systems have difficulties in selecting optimum system because of the diversity of such systems. On the other hand according to the considerable changes that the implementation of such systems at all levels of the organization willbring about, lack precision in selecting appropriate ERP systems leads to irreparable damage for the organization. This study attempts to resolve problems in selecting and implementing... 

    A primal-dual interior point method for solving environmental/economic power dispatch problem

    , Article International Review of Electrical Engineering ; Volume 6, Issue 3 , 2011 , Pages 1463-1473 ; 18276660 (ISSN) Bishe, H. M ; Kian, A. R ; Esfahani, M. S ; Sharif University of Technology
    2011
    Abstract
    We proposed a Primal-Dual Interior Point Method (PDIPM) to solve a combined Environmental and Economic Power Dispatch (EEPD) problem. The EEPD problem is a multiobjective problem with competing and non-commensurable objectives. The PDIPM produces a set of nondominated Pareto optimal solutions for the problem. Fuzzy set theory is employed to extract a compromise nondominated solution. The proposed algorithm is applied to the standard IEEE 30 bus six-generator test system. Comparison of our PDIPM results with the various algorithms reported in the literature shows that the solutions of the proposed algorithm are very accurate for the EEPD problem  

    Multiple attribute group decision making in interval type-2 fuzzy environment using a new distance formulation

    , Article International Journal of Operational Research ; Volume 24, Issue 1 , 2015 , Pages 17-37 ; 17457645 (ISSN) Heidarzade, A ; Mahdavi, I ; Mahdavi Amiri, N ; Sharif University of Technology
    Inderscience Enterprises Ltd  2015
    Abstract
    Type-2 fuzzy sets are generalisations of ordinary fuzzy sets in which the membership grades are characterised by fuzzy membership functions. Here, we consider the problem of finding the distance between two interval type-2 fuzzy sets (IT2-FSs). We define the formulation of calculating the distance between two IT2-FSs based on a new definition of centroid for an IT2-FS and explain an algorithm for obtaining it. Then, based on our proposed distance formulation, we present a method to deal with fuzzy multiple attributes group decision-making (FMAGDM) problems. We also use two examples to illustrate the FMAGDM process of the proposed method. The method provides us with a useful way to deal with... 

    Multiple attribute group decision making method using a new similarity measure in interval type-2 fuzzy sets: A case study

    , Article International Journal of Mathematics in Operational Research ; Volume 9, Issue 2 , 2016 , Pages 139-166 ; 17575850 (ISSN) Heidarzade, A ; Mahdavi, I ; Mahdavi Amiri, N ; Sharif University of Technology
    Inderscience Enterprises Ltd  2016
    Abstract
    Similarity measures are very important concepts in fuzzy sets theory. There are several definitions for similarity measures in both type-1 and interval type-2 fuzzy sets (IT2-FSs). Here, the problem of finding similarity between two IT2-FSs is considered. A new similarity measure is proposed and its performance is compared with existing approaches in literature. Furthermore, an application of this measure in multiple criteria group decision making problem is given. Based on the proposed similarity measure, the satisfaction degree for different alternatives are established which then are used to rank alternatives in multiple criteria group decision making. Finally, a case study concerning the... 

    The multi-objective supplier selection problem with fuzzy parameters and solving the order allocation problem with coverage

    , Article Journal of Modelling in Management ; Volume 15, Issue 3 , 2020 , Pages 705-725 Khalilzadeh, M ; Karami, A ; Hajikhani, A ; Sharif University of Technology
    Emerald Group Publishing Ltd  2020
    Abstract
    Purpose: This study aims to deal with supplier selection problem. The supplier selection problem has significantly become attractive to researchers and practitioners in recent years. Many real-world supply chain problems are assumed as multiple objectives combinatorial optimization problems. Design/methodology/approach: In this paper, the authors propose a multi-objective model with fuzzy parameters to select suppliers and allocate orders considering multiple periods, multiple resources, multiple products and two-echelon supply chain. The objective functions consist of total purchase costs, transportation, order and on-time delivery, coverage and the weights of suppliers. Distance-based... 

    Fuzzy type-2 nash equilibrium

    , Article 2008 International Conference on Computational Intelligence for Modelling Control and Automation, CIMCA 2008, Vienna, 10 December 2008 through 12 December 2008 ; 2008 , Pages 398-402 ; 9780769535142 (ISBN) Chakeri, A. R ; Habibi, J ; Heshmat, Y ; Sharif University of Technology
    2008
    Abstract
    In the past decade, fuzzy logic has been widely used to manage uncertainty in games. In this paper, we employ fuzzy logic to determine the priority of a payoff using linguistic preference relation. Preferences are derived according to the difference between payoffs using fuzzy IF-THEN rule. We introduce the concept of linguistic Nash equilibrium based on priority of each payoff. We assign a fuzzy set type2 to each cell to determine how much a cell has possibility to have a specific degree of being Nash. © 2008 IEEE  

    A comprehensive fuzzy TOPSIS model in multiple criteria decision making

    , Article 37th International Conference on Computers and Industrial Engineering 2007, Alexandria, 20 October 2007 through 23 October 2007 ; Volume 1 , 2007 , Pages 537-548 ; 9781627486811 (ISBN) Mahdavi, I ; Sadeghpour Gildeh, B ; Heidarzade, A ; Mahdavi Amiri, N ; Sharif University of Technology
    2007
    Abstract
    Decision making is the process of finding the best option among the feasible alternatives. In classical multiple criteria decision making (MCDM) methods, the ratings and the weights of the criteria are known precisely. Owning to vagueness of the decision data, the crisp data are inadequate for real-life situations. Since human judgments including preferences are often vague and cannot be expressed by exact numerical values, the application of fuzzy concepts in decision making is deemed to be relevant. Here, we apply a new distance formula to compute the standard deviation of fuzzy data to achieve crisp data by normalization. There is a flexibility to consider various fuzzy values as... 

    Reliability of slope stability analysis using fuzzy set

    , Article Annual Conference of the Canadian Society for Civil Engineering 2007: Where the Road Ends, Ingenuity Begins, Yellowknife, NT, 6 June 2007 through 9 June 2007 ; Volume 1 , 2007 , Pages 11-20 Bahador, M ; Sharif University of Technology
    2007
    Abstract
    In this research, theory of fuzzy sets is used to deal with the uncertain nature of soil parameters and the inaccuracy involved in the analysis simultaneously. Soil parameters are defined using suitable fuzzy sets and the uncertainty inherent in the value of factor of safety is assessed. It is believed that this approach accounts for the uncertainty in soil parameters more realistically compared to the conventional probabilistic approaches reported in the literature. The proposed method is applied to a case study and the results are discussed subsequently  

    Fuzzy multiple attribute decision making on water resources projects case study: ranking water transfers to zayanderud basin in Iran

    , Article Water International ; Volume 32, Issue 2 , 2007 , Pages 280-293 ; 02508060 (ISSN) Zarghaami, M ; Ardakanian, R ; Memariani, A ; Sharif University of Technology
    2007
    Abstract
    In this study, in order to create a decision-making model on water resources projects, a hierarchy of criteria has been developed by public participation. The Value Management methodology has been used for extraction of the effective criteria and attributes in the scope of Integrated Water Resources Management (IWRM). The hierarchy is generic for water resources management in the Islamic Republic of Iran. Since the evaluations of alternatives with respect to some attributes are uncertain and vague, fuzzy set theory has been used. By merging fuzzy set theory and multi-attribute decision-making a new Decision Support System (DSS), namely FDM, has been developed to compare different... 

    Duality in fuzzy number linear programming by use of a certain linear ranking function

    , Article Applied Mathematics and Computation ; Volume 180, Issue 1 , 2006 , Pages 206-216 ; 00963003 (ISSN) Mahdavi Amiri, N ; Nasseri, S. H ; Sharif University of Technology
    2006
    Abstract
    We explore some duality properties in fuzzy number linear programming problems. By use of a linear ranking function we introduce the dual of fuzzy number linear programming primal problems. We then present several duality results. © 2006 Elsevier Inc. All rights reserved