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    An optimal approach for maximizing the number of adjacencies in multi floor layout problem

    , Article International Journal of Production Research ; Volume 53, Issue 11 , 2015 , Pages 3462-3474 ; 00207543 (ISSN) Neghabi, H ; Ghassemi Tari, F ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    Multi-floor facility layout problem concerns the arrangement of departments on the different floors. In this paper, a new mathematical model is proposed for multi-floor layout with unequal department area. Maximising the number of useful adjacencies among departments is considered as the objective function. The adjacencies are divided into two major categories: horizontal and vertical adjacencies. The horizontal adjacency may be occurred between the departments assigned to same floors while the vertical can be happened between departments assigned to any consecutive floors. A minimum common boundary length (surface area) between any two horizontal (vertical) adjacent departments is... 

    A survey on multi-floor facility layout problems

    , Article Computers and Industrial Engineering ; Volume 107 , 2017 , Pages 158-170 ; 03608352 (ISSN) Ahmadi, A ; Pishvaee, M. S ; Akbari Jokar, M. R ; Sharif University of Technology
    Facility layout problem is a well-known optimization problem which generally deals with the arrangement of the facilities required in an organization. This problem has received much attention during the past decades. However, the researchers have mainly focused on the case where a single floor is available. While, in the competitive world, it is clear that using multi-floor structure layouts are much more efficient and in some cases necessary due to the nature of the functions and activities performed in the firms. Hence, this issue has recently attracted much attention and is becoming increasingly popular. Nevertheless, the lack of a review study on this subject for directing the new... 

    Constructing an optimal facility layout to maximize adjacency as a function of common boundary length

    , Article Engineering Optimization ; Volume 50, Issue 3 , 2018 , Pages 499-515 ; 0305215X (ISSN) Ghassemi Tari, F ; Neghabi, H ; Sharif University of Technology
    Taylor and Francis Ltd  2018
    An effective facility layout implies that departments with high flow are laid adjacent. However, in the case of a very narrow boundary length between the neighbouring departments, the adjacency would actually be useless. In traditional layout design methods, a score is generally assigned independent of the department’s boundary length. This may result in a layout design with a restricted material flow. This article proposes a new concept of adjacency in which the department pairs are laid adjacent with a wider path. To apply this concept, a shop with unequal rectangular departments is contemplated and a mathematical programming model with the objective of maximizing the sum of the adjacency... 

    Constructing a block layout by face area

    , Article International Journal of Advanced Manufacturing Technology ; Volume 54, Issue 5-8 , 2011 , Pages 801-809 ; 02683768 (ISSN) Jokar, M. R. A ; Sangchooli, A. S ; Sharif University of Technology
    Solving the facility layout problems by graph theory consists of two stages. In the first stage, a planar graph that specifies desired adjacencies is obtained and in the second stage, a block layout is achieved from the planar graph. In this paper, we introduce face area as a new concept for constructing a block layout. Based on this idea, we present a new algorithm for constructing block layout from a maximal planar graph (MPG). This MPG must be generated from deltahedron heuristic. Constructed block layout by this algorithm satisfies all of adjacency and area requirements  

    A new model for robust facility layout problem [electronic resource]

    , Article Information Sciences, Elsevier ; Volume 278, 10 September 2014, Pages 498–509 Neghabi, H. (Hossein) ; Eshghi, Kourosh ; Salmani, Mohammad Hassan ; Sharif University of Technology
    The Facility Layout Problem (FLP) is the problem of locating each department in a long plant floor without any overlap between departments in order to minimize the material handling cost. The main purpose of this study is to show the effectiveness of a robust approach to solve FLP. In this study, it is assumed that the departments’ length and width are not predetermined. For modeling this kind of uncertainty, the size of each department is considered as a bounded variable and two new parameters are also introduced to implement a robust approach. Moreover, a new adaptive algorithm is designed to determine the robust layout with respect to the decision makers’ requirements. Furthermore, the... 

    A new concept of adjacency for concurrent consideration of economic and safety aspects in design of facility layout problems

    , Article Journal of Loss Prevention in the Process Industries ; Volume 40 , 2016 , Pages 603-614 ; 09504230 (ISSN) Neghabi, H ; Ghassemi Tari, F ; Sharif University of Technology
    Elsevier Ltd  2016
    In this manuscript a new phenomenon of adjacency and closeness rating is proposed for constructing the optimal facility layout design. In the proposed approach, the closeness rating is applied to every pair of neighboring departments in a range of their attached point up to a predefined distance between them. Also, while in the traditional approach the closeness rating is applied for determining either the proximity or farness of two departments, the proposed approach considers both the degree of closeness as the economical purposes, and farness as the safety purposes concurrently. A mathematical model is proposed for constructing the optimal layout design. For evaluating the efficiency and... 

    Efficient VLSI layout of edge product networks

    , Article 4th IEEE International Symposium on Electronic Design, Test and Applications, DELTA 2008, Hong Kong, SAR, 23 January 2008 through 25 January 2008 ; 2008 , Pages 555-560 ; 0769531105 (ISBN); 9780769531106 (ISBN) Bakhshi, S ; Sarbazi Azad, H ; Sharif University of Technology
    The interconnection network between the processor cores in multiprocessors on chip has a crucial impact on the performance. Efficient VLSI layout area of such networks can result in lower costs and better performance. Layouts with more compact area can lead in shorter wires and therefore the signal propagation through the wires may take place in shorter time. In this paper, we study the VLSI layout bounds of a new product network, called the Edge Graph Product. Lower bounds are usually computed by the crossing number and bisection width of the topological graphs. For computing the bisection width and crossing number of the edge graph product, we use the obtained upper bound on maximal... 

    Multiple-Stage Mathematical Programming for Single and Multi-Floor Facility Layout Problems

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Abbas (Author) ; Akbari Jokar, Mohammad Reza (Supervisor)
    Single floor facility layout problem (FLP) is related to finding the arrangement of a given number of departments within a facility; in multi-floor FLP, the departments should be imbedded on some floors which are inside the facility. The significant influence of layout design on effectiveness of any organization has made FLP an important issue. This paper presents a three (two) stage mathematical programming method to find competitive solutions for multi (single) floor problems. The first stage assigns the departments to the floors by using a mixed integer programming model (the single floor version does not require this stage). The second stage uses a nonlinear programming model to specify... 

    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
    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... 

    A new linear adjacency approach for facility layout problem with unequal area departments

    , Article Journal of Manufacturing Systems ; Volume 37, Part 1 , October , 2015 , Pages 93-103 ; 02786125 (ISSN) Ghassemi Tari, F ; Neghabi, H ; Sharif University of Technology
    Elsevier  2015
    In this study a new version of adjacency, which provides a more flexible layout design, is proposed. In the proposed version, departments which are nonadjacent yet close to each other are considered to be adjacent with a smaller adjacency rating. It is shown that the proposed adjacency is a generalized version of the traditional adjacency. A mathematical programming model is developed for the proposed facility layout problem. To show the flexibility and efficacy of the proposed model, a computational study is conducted. The solution of an illustrative example as well as the solutions of several test problems, reveal flexibility and efficacy of the proposed model  

    A Facilities Layout Algorithm for Maximizing Adjacency Score

    , M.Sc. Thesis Sharif University of Technology Shoja Sangchooli, Ali (Author) ; Akbari, Mohammad Reza (Supervisor)
    Facility layout is one of the most important problems in industrial engineering and Operation Research. Facility layout problem is concerned with the determination of the most effective arrangement and configuration of physical facilities. The most successful heuristic approaches are based on graph theoretic concepts. solving facility layout problem by graph theory consists of two stages. In the first stage a planar graph which specifies desired adjacencies is obtained and in the second stage a Block layout is achieved from the planar graph which satisfies adjacency and area requirements. In this Research, a branch and bound algorithm will be suggested for WMPG Problem. The algorithm can... 

    Wind farm layout optimization using imperialist competitive algorithm

    , Article Journal of Renewable and Sustainable Energy ; Vol. 6, Issue. 4 , July , 2014 ; ISSN: 19417012 Kiamehr, K ; Hannani, S. K ; Sharif University of Technology
    In this work, the wind farm layout optimization problem is dealt with using a new approach. The aim of wind farm layout optimization is to maximize the output power of a wind farm considering the wake losses. Layout optimization minimizes the wake losses regarding the location of the turbines. Three different wind scenarios with different wind direction angles, wind direction blowing probabilities, and Weibull distribution parameters are assumed. Since, the problem is nonlinear and constrained, imperialist competitive algorithm is used as a modern and powerful algorithm for continuous optimization problems. The optimization outcomes indicate that imperialist competitive algorithm yields... 

    Code layout optimization for Near-Ideal instruction cache

    , Article IEEE Computer Architecture Letters ; Volume 18, Issue 2 , 2019 , Pages 124-127 ; 15566056 (ISSN) Ansari, A ; Lotfi Kamran, P ; Sarbazi Azad, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Instruction cache misses are a significant source of performance degradation in server workloads because of their large instruction footprints and complex control flow. Due to the importance of reducing the number of instruction cache misses, there has been a myriad of proposals for hardware instruction prefetchers in the past two decades. While effectual, state-of-the-art hardware instruction prefetchers either impose considerable storage overhead or require significant changes in the frontend of a processor. Unlike hardware instruction prefetchers, code-layout optimization techniques profile a program and then reorder the code layout of the program to increase spatial locality, and hence,... 

    Modelling and improvement of non-standard queuing systems: A gas station case study

    , Article International Journal of Applied Decision Sciences ; Volume 4, Issue 4 , 2011 , Pages 324-340 ; 17558077 (ISSN) Teimoury, E ; Yazdi, M. M ; Haddadi, M ; Fathi, M ; Sharif University of Technology
    This research has modelled a queuing system with no standard states. In order to analyse these systems, some parameters such as the mean of waiting time and the length of queue are computed. These situations usually occur when there is delay in the service, for example, in the gas queuing system that cars are unable to leave after receiving the required services due to the presence of other cars in front of them. These kinds of non-standard queuing systems are usually applied to the assembly and production lines. In this paper, a queuing model for the special non-standard state queuing system is developed to be used in gas stations. The proposed model is implemented in fuel stations in Iran... 

    Loop-based facility layout design under flexible bay structures

    , Article International Journal of Production Economics ; Volume 193 , 2017 , Pages 713-725 ; 09255273 (ISSN) Asef Vaziri, A ; Jahandideh, H ; Modarres, M ; Sharif University of Technology
    We develop heuristic procedures for concurrent design of block layout, material flow network, and input and output stations. Unlike the common practice in the flexible bay structure layout design, our objective function includes both loaded and empty flow between pairs of I/O stations. This measure of effectiveness is the main determinant of the fleet size of the vehicles, which in turn is the major driver of the total investment and operational costs in vehicle-based material handling. Our work is the first to design flexible bay structure layouts for loop-based material flow patterns. We first develop heuristic algorithms to configure the layout on the foundations of a unidirectional loop... 

    Visibility of a moving segment

    , Article Proceedings of the 2009 International Conference on Computational Science and Its Applications, ICCSA 2009, 29 June 2009 through 2 July 2009, Yongin ; 2009 , Pages 169-176 ; 9780769537016 (ISBN) Nouri Bygi, M ; Ghodsi, M ; Sharif University of Technology
    In this paper we define topological segment visibility, and show how to compute and maintain it as the observer moves in the plane. There are n non-intersecting line segment objects in the plane, and we have a segment observer among them. As the topological visibility of a line segment has not been studied before, we first consider static case of the problem, in which the observer and objects are static, and then we study dynamic case of the problem, in which the observer can move among obstacles  

    A Decision Analysis for Production Layout Selection

    , M.Sc. Thesis Sharif University of Technology Rooygari, Homa (Author) ; Eshghi, Kourosh (Supervisor)
    Studying the major effects of facility layout on competitive abilities has been a field of interest for researchers. Selection of production layout is amongst the most important decisions because it has a major role on the efficiency of a company like the ability of quick respond to customers’ diverse needs.
    In this study we intend to obtain a ranking of production layouts considering agility in production which leads to responding quickly to the diversity of demand. Considering the nature of a decision making problem, we use PSI method. This is a multi attribute decision making method in which there is no need for considering the relative importance between the attributes. The main... 

    Maximizing the Number of Adjacencies in a Multi Floor Facility Layout Problem with Unequal Rectangular Departments

    , Ph.D. Dissertation Sharif University of Technology Neghabi, Hossein (Author) ; Ghasemi-Taromi, Farhad (Supervisor) ; Hajji, Alireza (Co-Advisor)
    Facility layout problem (FLP) is one of classical optimization problem in engineering science. The theoretical attractiveness and practical applications of the problem have created a rich literature in the FLP. There are varieties of measure of effectiveness’s for the FLPs, such as minimizing the space cost; minimizing the handing cost; maximizing the adjacencies; maximizing the safety and etc. Maximization of the adjacencies is a common measure of effectiveness, which is addressed in many related literatures especially, in continuous process facility layout. Using of the classical definition of the adjacency usually impose some restrictions on the layout designs. Due to these restrictions... 

    Safety of Plant Layout by Risk Assessment

    , M.Sc. Thesis Sharif University of Technology Moghaddasi, Mahboubeh (Author) ; Rashtchian, Davood (Supervisor)
    One of the most important stages to designing a process plant is layout of equipment in unit area. There are plenty of routine procedures to find out equipment arrangement and their separation distances based on process and cost criteria. One of this Procedures is the use of codes and standards. Although some studies have been carried out to enter safety parameters to conventional procedures, the problem complexity because of the number of involved equipment is still of concern. To clear these ambiguities, the new approach presented in this thesis is aimed at quantifying the effects of adjacent equipment on each other. In this way, fire radiation and explosion have been selected as the major... 

    Room Layout Estimation and Perception through Cross-task Consistency and Knowledge Fusion

    , M.Sc. Thesis Sharif University of Technology Saberi, Ali (Author) ; Bagheri Shouraki, Saeed (Supervisor)
    Wall detection, as a part of scene understanding and indoor 3D modeling, can be used in robotic, architecture, and augmented reality. In robotic, scene analysis and understanding is knows as one of the main steps in robot navigation and simultaneous localization and mapping and walls need to be detected to form a 3D map of indoor environment. Ceiling and floor are also important elements of an indoor environment, therefore we can see our problem as a room layout estimation if we consider ceiling and floor. Using a deep learning structure, we estimate room layout in a semantic segmentation manner. Our approach is real-time. Our proposed method uses a deep fully-convolutional network, layout...