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    Lagrangian relaxation heuristics for the uncapacitated single-source multi-product facility location problem

    , Article International Journal of Production Economics ; Volume 145, Issue 2 , 2013 , Pages 713-723 ; 09255273 (ISSN) Mohammad Nezhad, A ; Manzour, H ; Salhi, S ; Sharif University of Technology
    2013
    Abstract
    Facility location problem is one of the strategic logistical drivers within the supply chain which is a hard to solve optimization problem. In this study, we focus on the uncapacitated single-source multi-product production/ distribution facility location problem with the presence of set-up cost. To efficiently tackle this decision problem, two Lagrangian-based heuristics are proposed one of which incorporates integer cuts to strengthen the formulation. Local search operators are also embedded within these methods to improve the upper bounds as the search progresses. Three sets of instances with various characteristics are generated and used to evaluate the performance of the proposed... 

    A resource constrained project scheduling problem with fuzzy random duration [electronic resource]

    , Article Journal of Uncertain Systems ; Vol.4, No.2, pp.123-132, 2010 Nematian, J. (Javad) ; Eshghi, Kourosh ; Eshragh Jahromi, Abdolhamid ; Sharif University of Technology
    Abstract
    In this paper, first a fuzzy random resource-constrained project scheduling problem is presented. The object of the problem is to find the optimal scheduling of project activities. In this model, duration of project activities is a fuzzy random variable. Then, the proposed model is formulated by using the expected value of fuzzy random variables as an IP model. An illustrative example is also provided to clarify the concept. © 2010 World Academic Press, UK. All rights reserved  

    A special class of fuzzy integer programming model with all different constraints [electronic resource]

    , Article Scientia Iranica ; Vol. 16, No. 1, pp. 1-10, 2009 Eshghi, K. (Kourosh) ; Nematian, Javad ; Sharif University Of Technology
    Abstract
    In this paper, a fuzzy approach is applied to special classes of integer programming problems with all diierent constraints. In the rst model, a fuzzy integer programming model is developed to represent the all-diierent constraints in mathematical programming. In order to solve the proposed model, a new branching scheme for the Branch and Bound algorithm is also presented. In the second model, a special class of large-scale multi-objective fuzzy integer programming problems with all-diierent constraints is introduced. A solution method for the proposed model is also developed by using the decomposition technique, weighting method and Branch and Bound algorithm. An illustrative numerical... 

    Fuzzy reliability optimization models for redundant systems [electronic resource]

    , Article International Journal of Industrial engineering ; July 2008, Vol. 4, No. 7, 1-9 Nematian, J. (Javad) ; Eshghi, Kourosh ; Eshraghniaye Jahromi, Abdolhamid ; Sharif University of Technology
    Abstract
    In this paper, a special class of redundancy optimization problem with fuzzy random variables is presented. In this model, fuzzy random lifetimes are considered as basic parameters and the Er-expected of system lifetime is used as a major type of system performance. Then a redundancy optimization problem is formulated as a binary integer programming model. Furthermore, illustrative numerical examples are also given to clarify the methods discussed in this paper  

    A mixed integer linear programming based approach for unit commitment in smart grid environment

    , Article Journal of Engineering Research ; Vol. 2, issue. 3 , November , 2014 , p. 131-157 ; 23071877 Ghadiri Anari, R ; Rashidinejad, M ; Fotuhi-Firuzabad, M ; Sharif University of Technology
    Abstract
    The future of power systems known as smart grids is expected to involve an increasing level of intelligence and incorporation of new information and communication technologies in every aspect of the power grid. Demand response resources and gridable vehicle are two interesting programs which can be utilized in the smart grid environment. Demand response resources can be used as a demand side virtual power plant (resource) to enhance the security and reliability of utility and have the potential to offer substantial benefits in the form of improved economic efficiency in wholesale electricity markets. An economic model of incentive responsive loads is modelled based on price elasticity of... 

    Modeling formulation and a new heuristic for the railroad blocking problem

    , Article Applied Mathematical Modelling ; Volume 56 , 2018 , Pages 304-324 ; 0307904X (ISSN) Hasany, R. M ; Shafahi, Y ; Sharif University of Technology
    Elsevier Inc  2018
    Abstract
    The railroad blocking problem is an important issue at the tactical level of railroad freight transportation. This problem consists of determining paths between the origins and destinations of each shipment to minimize the operating and user costs while satisfying the railroad supply and demand restrictions. A mixed-integer program (MIP) is developed to find the optimal paths, and a new heuristic is developed to solve the proposed model. This heuristic decomposes the model into two sub-problems of manageable size and then provides feasible solutions. We discuss the performance of the proposed heuristic for a set of instances with up to 90 stations. A comparison with the CPLEX MIP solver... 

    Improved linear cryptanalysis of reduced-round SIMON-32 and SIMON-48

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 6 December 2015 through 9 December 2015 ; Volume 9462 , December , 2015 , Pages 153-179 ; 03029743 (ISSN); 9783319266169 (ISBN) Abdelraheem, M. A ; Alizadeh, J ; Alkhzaimi, H. A ; Aref, M. R ; Bagheri, N ; Gauravaram, P ; Biryukov A ; Goyal V ; Sharif University of Technology
    Springer Verlag  2015
    Abstract
    In this paper we analyse two variants of SIMON family of light-weight block ciphers against variants of linear cryptanalysis and present the best linear cryptanalytic results on these variants of reducedround SIMON to date. We propose a time-memory trade-off method that finds differential/ linear trails for any permutation allowing low Hamming weight differential/ linear trails. Our method combines low Hamming weight trails found by the correlation matrix representing the target permutation with heavy Hamming weight trails found using a Mixed Integer Programming model representing the target differential/linear trail. Our method enables us to find a 17-round linear approximation for SIMON-48... 

    A bi-objective MIP model for facility layout problem in uncertain environment

    , Article International Journal of Advanced Manufacturing Technology ; Volume 81, Issue 9-12 , 2015 , Pages 1563-1575 ; 02683768 (ISSN) Salmani, M. H ; Eshghi, K ; Neghabi, H ; Sharif University of Technology
    Abstract
    Facility layout problem (FLP) is one of the classical and important problems in real-world problems in the field of industrial engineering where efficiency and effectiveness are very important factors. To have an effective and practical layout, the deterministic assumptions of data should be changed. In this study, it is assumed that we have dynamic and uncertain values for departments’ dimensions. Accordingly, each dimension changes in a predetermined interval. Due to this assumption, two new parameters are introduced which are called length and width deviation coefficients. According to these parameters, a definition for layout in uncertain environment is presented and a mixed integer... 

    Security constrained unit commitment with flexibility in natural gas transmission delivery

    , Article Journal of Natural Gas Science and Engineering ; Volume 27, Part 2 , November 2015 , 2015 , Pages 632–640 ; 18755100 (ISSN) Badakhshan, S ; Kazemi, M ; Ehsan, M ; Sharif University of Technology
    Elsevier  2015
    Abstract
    This paper presents a formulation of fuzzy optimization for uncertainties in natural gas in fuel constraints for hourly individual unit and total unit fuel consumptions. Security Constrained Unit Commitment (SCUC) is usually a mixed integer programming and gas load flow has a non-linear equation a genetic algorithm is proposed to solve natural gas transmission network. A fuzzy mixed integer programming optimization is briefly discussed and adapted to deal with security constrained unit commitment schedule. Finally, two case studies are investigated (IEEE 6-bus system with 7-node natural gas transmission grid and the IEEE 118-bus power system linked with 14-node gas transmission test system)... 

    A robust mathematical model and ACO solution for multi-floor discrete layout problem with uncertain locations and demands

    , Article Computers and Industrial Engineering ; Volume 96 , 2016 , Pages 237-248 ; 03608352 (ISSN) Izadinia, N ; Eshghi, K ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    The Multi-Floor Layout Problem (MFLP) is the problem of finding the position of each department in a plant floor in a multi-floor building without any overlapping between departments in order to optimize a particular objective function, more commonly the sum of the material handling costs. In this paper, a special class of MFLP, called Uncertain Multi-Floor Discrete Layout Problem (UMFDLP), is defined. In this problem, a multi-floor building is considered in which an underground store is utilized to contain main storages, and different departments can be located in the other floors in potential pre-determined locations. Furthermore, all material flows are not constant. Moreover, the... 

    An imperialist competitive algorithm for service composition and optimal selection in cloud manufacturing

    , Article 5th International Symposium on Computational and Business Intelligence, ISCBI 2017, 11 August 2017 through 14 August 2017 ; 2017 , Pages 129-133 ; 9781538617717 (ISBN) Akbaripour, H ; Houshmand, M ; Kerdegari, A ; Sharif University of Technology
    Abstract
    Cloud manufacturing is an emerging service-oriented manufacturing paradigm that integrates and manages distributed manufacturing resources through which complex manufacturing demands with a high degree of customization can be fulfilled. The process of Service Composition and Optimal Selection (SCOS) is an important issue for practical implementation of cloud manufacturing. In this paper, a new Mixed Integer Programming (MIP) model for solving the SCOS with transportation consideration has been proposed. This model minimizes both manufacturing and transportation costs subject to some constraints such as necessity of transportation between manufacturing resources and the requirements specified... 

    Cloud manufacturing service selection optimization and scheduling with transportation considerations: mixed-integer programming models

    , Article International Journal of Advanced Manufacturing Technology ; Volume 95, Issue 1-4 , 2018 , Pages 43-70 ; 02683768 (ISSN) Akbaripour, H ; Houshmand, M ; van Woensel, T ; Mutlu, N ; Sharif University of Technology
    Springer London  2018
    Abstract
    Cloud manufacturing is an emerging service-oriented manufacturing paradigm that integrates and manages distributed manufacturing resources through which complex manufacturing demands with a high degree of customization can be fulfilled. The process of service selection optimization and scheduling (SSOS) is an important issue for practical implementation of cloud manufacturing. In this paper, we propose new mixed-integer programming (MIP) models for solving the SSOS problem with basic composition structures (i.e., sequential, parallel, loop, and selective). Through incorporation of the proposed MIP models, the SSOS with a mixed composition structure can be tackled. As transportation is... 

    Service composition and optimal selection in cloud manufacturing: landscape analysis and optimization by a hybrid imperialist competitive and local search algorithm

    , Article Neural Computing and Applications ; 2018 ; 09410643 (ISSN) Akbaripour, H ; Houshmand, M ; Sharif University of Technology
    Springer London  2018
    Abstract
    Cloud manufacturing as an emerging service-oriented manufacturing paradigm integrates and manages geographically distributed manufacturing resources such that complex and highly customized manufacturing tasks can be performed cooperatively. The service composition and optimal selection (SCOS) problem, in which manufacturing cloud services are optimally selected for performing subtasks, is one of the key issues for implementing a cloud manufacturing system. In this paper, we propose a new mixed-integer programming model for solving the SCOS problem with sequential composition structure. Unlike the majority of previous research on the problem, in the proposed model, the transportation between... 

    Service composition and optimal selection in cloud manufacturing: landscape analysis and optimization by a hybrid imperialist competitive and local search algorithm

    , Article Neural Computing and Applications ; Volume 32, Issue 15 , 2020 , Pages 10873-10894 Akbaripour, H ; Houshmand, M ; Sharif University of Technology
    Springer  2020
    Abstract
    Cloud manufacturing as an emerging service-oriented manufacturing paradigm integrates and manages geographically distributed manufacturing resources such that complex and highly customized manufacturing tasks can be performed cooperatively. The service composition and optimal selection (SCOS) problem, in which manufacturing cloud services are optimally selected for performing subtasks, is one of the key issues for implementing a cloud manufacturing system. In this paper, we propose a new mixed-integer programming model for solving the SCOS problem with sequential composition structure. Unlike the majority of previous research on the problem, in the proposed model, the transportation between... 

    Minimum cost multiple multicast network coding with quantized rates

    , Article Computer Networks ; Volume 57, Issue 5 , 2013 , Pages 1113-1123 ; 13891286 (ISSN) Raayatpanah, M. A ; Salehi Fathabadi, H ; Khalaj, B. H ; Khodayifar, S ; Sharif University of Technology
    2013
    Abstract
    In this paper, we consider multiple multicast sessions with intra-session network coding where rates over all links are integer multiples of a basic rate. Although having quantized rates over communication links is quite common, conventional minimum cost network coding problem cannot generally result in quantized solutions. In this research, the problem of finding minimum cost transmission for multiple multicast sessions with network coding is addressed. It is assumed that the rate of coded packet injection at every link of each session takes quantized values. First, this problem is formulated as a mixed integer linear programming problem, and then it is proved that this problem is strongly... 

    On the odd girth and the circular chromatic number of generalized Petersen graphs

    , Article Journal of Combinatorial Optimization ; Volume 33, Issue 3 , 2017 , Pages 897-923 ; 13826905 (ISSN) Daneshgar, A ; Madani, M ; Sharif University of Technology
    Springer New York LLC  2017
    Abstract
    A class G of simple graphs is said to be girth-closed (odd-girth-closed) if for any positive integer g there exists a graph G ∈ G such that the girth (odd-girth) of G is ≥ g. A girth-closed (odd-girth-closed) class G of graphs is said to be pentagonal (odd-pentagonal) if there exists a positive integer g∗ depending on G such that any graph G ∈ G whose girth (odd-girth) is greater than g∗ admits a homomorphism to the five cycle (i.e. is C5-colourable). Although, the question “Is the class of simple 3-regular graphs pentagonal?” proposed by Nešetřil (Taiwan J Math 3:381–423, 1999) is still a central open problem, Gebleh (Theorems and computations in circular colourings of graphs, 2007) has... 

    On optimal dynamic pegging in rescheduling for new order arrival

    , Article Computers and Industrial Engineering ; Volume 136 , 2019 , Pages 46-56 ; 03608352 (ISSN) Moghaddam, S. K ; Saitou, K ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    A rescheduling method for new order arrival is presented based on the concept of dynamic pegging in multi-level production. Upon the arrival of new, unplanned orders, dynamic pegging enables the re-assignment of the Work-In-Progress (WIP) to the existing or newly arrived orders in such a way that the cost of rescheduling is minimized. A simple yet inspiring Mixed Integer Programming (MIP) model is proposed that combines dynamic pegging with rescheduling. The resulting schedules are compared with the ones obtained from two other basic rescheduling approaches. Analysis of the comparisons confirm the superiority of the proposed method in terms of total rescheduling costs. © 2019  

    Sectionalizing switch placement in distribution networks considering switch failure

    , Article IEEE Transactions on Smart Grid ; Volume 10, Issue 1 , 2019 , Pages 1080-1082 ; 19493053 (ISSN) Farajollahi, M ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Sectionalizing switches play a crucial role in enhancing service reliability to the end users of distribution networks. However, they might encounter failures, thereby causing interruptions in the networks. The existing switch placement models consider only the pros of switches in improving service reliability, while they fail to deem switches cons in possible failures and thus increasing system interruptions. This letter intends to show the importance of switch failure in the switch placement problem and the extent to which switch failure alters the switches allocation in a network. To do so, we develop a novel model based on mixed integer programming format to integrate the impacts of... 

    Sectionalizing switch placement in distribution networks considering switch failure

    , Article IEEE Transactions on Smart Grid ; Volume 10, Issue 1 , 2019 , Pages 1080-1082 ; 19493053 (ISSN) Farajollahi, M ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Sectionalizing switches play a crucial role in enhancing service reliability to the end users of distribution networks. However, they might encounter failures, thereby causing interruptions in the networks. The existing switch placement models consider only the pros of switches in improving service reliability, while they fail to deem switches cons in possible failures and thus increasing system interruptions. This letter intends to show the importance of switch failure in the switch placement problem and the extent to which switch failure alters the switches allocation in a network. To do so, we develop a novel model based on mixed integer programming format to integrate the impacts of... 

    Blood Inventory Management in Hospitals: Considering the Uncertainty
    of Supply, Demand and Blood Transshipment

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Ali (Author) ; Najafi, Mehdi (Supervisor)
    Abstract
    In recent years there is a growing trend in designing efficient health care systems. The applications of operations research have been instrumental in advancing this growing trend too. The blood management issue has raised concerns for human on the other hand. Blood is one of the vital commodities in the field of health. Despite significant advances in the field of medicine, a suitable replacement for this vital commodity has not been found yet. Collecting and managing the distribution of blood that is discussed in the blood supply chain management, requires careful planning and managing. In this research blood inventory management in hospitals considering the uncertainty of supply, demand...