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Total 455 records

    Development of a Covering Location Model in Congested Networks

    , M.Sc. Thesis Sharif University of Technology Golchin Khiabani Azar, Negar (Author) ; Shavandi, Hassan (Supervisor)
    Abstract
    Plants, distribution centers, and other facilities generally function for years or decades, during which time the environment in which they operate may change substantially. Costs, demands, travel times, and other inputs to classical facility location models may be highly uncertain. So when making decisions of location considering the factors that may change is beneficial. In this thesis a version of covering location model under uncertainty in a congested system is proposed. The aim is to locate m facilities to maximize the captured customer utility, having in mind that there may be up to q facilities established in future; the only information at hand about the number of the new facilities... 

    A Decision Support System (DSS) for Relief Logistics in the Event of an Unexpected Natural Disaster

    , M.Sc. Thesis Sharif University of Technology Komijani Bozcheloei, Elham (Author) ; Eshghi, Kourosh (Supervisor)
    Abstract
    Examples from recent years, such as Covid-19 disease and earthquakes, show that disasters can have devastating effects on a community.These disasters are divided into two categories: expected and unexpected. decision makers cannot easily determine the time, severity and effects of them. Therefore, they must coordinate their decisions in the pre-disaster and post-disaster stages according to the incomplete information available, and according to the dynamics of the situation, quickly understand and interpret the connections between different decisions. Among the various approaches, the decision support system can explore the variable and unpredictable nature of such issues and enable decision... 

    Counter-Measure Against Power Analysis Attacks Using Dual-Rail Logic in Reconfigurable Devices

    , M.Sc. Thesis Sharif University of Technology Kashiri, Jamaladdin (Author) ; Bayat Sarmadi, Siavash (Supervisor) ; Asadi, Hossein (Supervisor)
    Abstract
    Naïve hardware implementation of encryption modules can cause leakage about the secret information. Attackers can use this information to extract the secret key. This approach is known as side channel attack (SCA). An example of such attacks is differential power analysis (DPA), which uses a number of traces of power consumption of the encryption device. One of the proposed methods to deal with such attack is using dual rail logic. In previous implementations based on a dual rail logic, symmetric complementary mapping with the cross coupling and pre-charging is being used. This method has relatively high delay and cost; however, significant increase in the level of security can be achieved.... 

    Cooperative Multi Camera Localization

    , M.Sc. Thesis Sharif University of Technology Karimian Shahri, Mahdi (Author) ; hossein Khalaj, Babak (Supervisor)
    Abstract
    Using camera in localization its pose and connected things, with using camera images has been inspected in this thesis which categorized in passive localization. Although using these methods seems to be rather difficult, human can passively perceive its position in space. This is a preface for new positioning systems.
    In this thesis assume that some cameras are ready for Image sharing then we introduce algorithms for cameras relative locations and rotation matrices. This method gives local information and can uses range scaners as inputs. Other works in last decade tryed on 3D reconstruction and graphic section and rarely explored multi-camera localization and reduction of its... 

    Localization of Active Aerial Targets Using Targets with Known Location

    , M.Sc. Thesis Sharif University of Technology Kaviani, Saber (Author) ; Behnia, Feridoon (Supervisor)
    Abstract
    Localization of radio, acoustic and vibration wave’s sources by passive systems has many applications in positioning systems, navigation systems, wireless sensor networks, defense, security, and geophysics. RSS, AOA, TDOA, and FDOA are some of the techniques available for passive localization. The performance of TDOA/FDOA techniques does not degrade with distance and multipath, but it may suffer from poor performance for narrowband signals. On the other hand, FDOA technique requires narrowband signals. Thus, the combination of TDOA and FDOA can be suitable for a much wider range of sources. In addition, the TDOA/FDOA method can provide more accurate interference source localization compared... 

    Truck and Motorcycle Routing Problem with Mobile Delivery Location

    , M.Sc. Thesis Sharif University of Technology Kazemi, Peyman (Author) ; Akbari Jokar, Mohammad Reza (Supervisor)
    Abstract
    The emergence and development of E-commerce prompted many companies to reduce their cost by seeking new solutions that improve customer satisfaction level and product distribution. In this research, the coordination of a truck and a motorcycle is considered to utilize both vehicles' benefits. The mobile location of customers is another assumption in this research. Therefore, it is possible for customers to suggest different delivery times and locations. Based on the customer situation, there are three location modes which specify the accessibility. In this study, a mixed-integer linear programming model is presented to minimize service completion time. In addition, two metaheuristic... 

    Seismic Performance of Partitions in RC Buildings

    , Ph.D. Dissertation Sharif University of Technology Kazerounian, Alireza (Author) ; Kazemi, Mohammad Taghi (Supervisor)
    Abstract
    Many reinforced concrete frame buildings with masonry partitions have been built all around the world. Observations from past earthquakes show that the partitions can endanger the life of buildings occupants and lead to significant damage and loss. Failure of the partitions can be caused by dynamic vibrations and in-plane and out-of-plane loads/displacements. The interaction between in-plane and out-of-plan behaviors and location of partitions, nonlinearity and higher modes of the structures could affect the out-of- plane seismic demands on partitions. Therefore, there is a need for a comprehensive assessment in order to limit the loss in buildings with masonry partitions. This research... 

    Optimum Process Unit Layout via Risk Assessment

    , M.Sc. Thesis Sharif University of Technology Kareshki, Hamid (Author) ; Rashtchian, Davood (Supervisor)
    Abstract
    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. 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 hazard that any equipment can expose on the other items,... 

    The Bi-objective Capacitated Facility Location-Network Design Problem with Multi-type of Links and Facilities

    , M.Sc. Thesis Sharif University of Technology Charkhgard, Parisa (Author) ; Eshghi, Kourosh (Supervisor)
    Abstract
    One of the primary concerns on many traditional capacitated facility location-network design problems is to consider costs of transportation and establishing of facilities in one single objective function. Considering a single objective in these problems may lead to misleading solutions due to the fact that the transportation costs should be considered in a short-term period of time, and therefore, the higher cost of establishing the facilities may unfairly dilute the role of the transportation cost. In this thesis, we introduce the capacitated facility location-network design problem with two separate objective functions. Moreover, in this problem, it is assumed that for connecting two... 

    Locating Wireless Transmitters by Using Maximal Covering Location Problem and Hata Model

    , M.Sc. Thesis Sharif University of Technology Charkhgard, Hadi (Author) ; Akbari Jokar, Mohammad Reza (Supervisor)
    Abstract
    Locating wireless transmitters is one of the most important issues. That’s why many researchers have worked in this subject recently. Communication Engineers always want to optimize the productivity of wireless transmitters. They prefer to cover a region completely by minimum cost, so they use analytical tools for solving this kind of problems. This type of optimization is very useful for cellular Networks. There is a different kind of wireless services such as high-speed Internet services; their goal is maximizing the covered demand points by minimum cost not covering all of them. Experts use maximal covering location problem for modeling this kind of problems. At first, an extension of one... 

    A Heuristic Algorithm for Dynamic Maximal Covering Location Problem with a Choice of Selecting the Number of Facilities

    , M.Sc. Thesis Sharif University of Technology Chavoshi, Saeed (Author) ; Kourosh, Eshghi (Supervisor)
    Abstract
    The Dynamic Maximal Covering Location Problem (DMCLP), is one of the classes of Facility Location Problem (FLP) with a wide raneg of applications in real-life situations. In order to solve this problem, this research presents a sufficient greedy heuristic algorithm, which is capable of solving the DMCLP in large scales of 2500 demand nodes and potential facilities of 200 in 5 periods in a negligible computation time in comparison to those with exact algorithms such as branch and cut. Furthermore, in this research DMCLP is also modified to reach reach a more realistic model. In this new model, a cost behaviour is defined according to the number of facilities located. Subsequently, the new... 

    Warehouses Location Model with Capacity Constraint

    , M.Sc. Thesis Sharif University of Technology Pishbin, Payam (Author) ; Kianfar, Farhad (Supervisor)
    Abstract
    In this thesis, an inventory- location model considering capacity constraints and coverage radius is described in which the capacity is determined based on the maximum accumulation inventory. This model, through minimizing the sum of the fixed facility location costs, transportation costs and safety stock and working inventory costs, concurrently, determines warehouse location, assignment of retailers to warehouses, shipment sizes from the plant to warehouses, working inventory and safety stock levels at the warehouses. This problem can be formulated as a nonlinear mixed integer program in which the objective function is neither concave nor convex. Lagrangian relaxation is incorporated for... 

    Using Simulation-Optimization Approach for Fire Station Location and Vehicle Assignment Problem: a Case Study in Tehran, Iran

    , M.Sc. Thesis Sharif University of Technology Pirmohammadi, Ali (Author) ; Amini, Zahra (Supervisor)
    Abstract
    In this research, the problem of locating fire stations and allocating equipment has been studied and a simulation-optimization approach has been presented to solve the problem. The mathematical models of this research were developed based on the idea of the randomness of the covered demand and the maximum expected coverage model. In these models, the issue of non-availability of equipment to cover accidents, the random nature of accidents, various fire incidents and the equipment needed to cover them are considered. Two mathematical models with deterministic and non-deterministic approach with different scenarios for demand are proposed. The non-deterministic model is developed with the aim... 

    Developing a Joint Location-Inventory-Transportation Model under Uncertainty

    , M.Sc. Thesis Sharif University of Technology Poursaeidi, Mohammad Hossein (Author) ; Mahlooji, Hashem (Supervisor)
    Abstract
    In this research, an integrated location-inventory-transportation problem with uncertainty in the parameters is analyzed using Robust Optimization techniques. Unknown demand distribution is the underlying assumption, which relates better to the reality. The model’s main purpose is to determine the number and locations of the Distribution Centers (DC) that connect the supplier to the retailers, and then to assign retailers to them. The problem’s mathematical model is developed on the basis of Robust Optimization techniques and the solution space is explored by Tabu Search. The results show that the Tabu Search method achieves optimality in small-scale cases, while providing desirable... 

    Location Routing Inventory Problem Using Robust Optimization Approach

    , M.Sc. Thesis Sharif University of Technology Heyhat, Shaghayegh (Author) ; Akbari Jokar, Mohammad Reza (Supervisor)
    Abstract
    This thesis studies a multi–period location–routing–inventory problem in a three layer supply chain including manufacturers, distribution centers and customers with consideration of capacity constraint in distribution centers and heterogeneous fleet of vehicles. Moreover, the demand parameter is considered uncertain and there is no available information about distribution function of demand parameter. For handling problem uncertainty, Bertsimas and sim robust optimization approach is used and a mixed integer programming is presented for both deterministic problem and robust counterpart problem. Then simulated annealing and genetic algorithms are proposed to solve the model.... 

    A New Method for Finding Core Location and Arrival Direction of Extensive Air Showers

    , Ph.D. Dissertation Sharif University of Technology Hedayati, Hadi (Author) ; Samimi, Jalal (Supervisor) ; Anvari, Abbas (Supervisor) ; Bahmanabadi, Mahmoud (Supervisor)
    Abstract
    The most important aspects of extensive air shower studies are finding energy, mass and the arrival direction of primary cosmic ray particles. In order for these parameters to be established, the core position of extensive air showers should be determined. In this thesis, a new method has been introduced that utilizes trigger time information of particle detectors for finding extensive air showers core location and for correcting plane wave front approximation to reconstruct their arrival direction. This method, in its simplest form, does not depend on density-sensitive detectors which are sensitive to the number of crossing particles. It is also independent of lateral distribution models.... 

    Vehicle Identification Sensors Location Problem with the Purpose of Origin-destination Estimation

    , Ph.D. Dissertation Sharif University of Technology Hadavi, Majid (Author) ; Shafahi, Yousef (Supervisor)
    Abstract
    Origin-Destination (OD) table is an important input for managing and controling processes of transportation systems. OD flow estimation based on the observations of traffic sensors is a famous way of attaining this table. Technology developments in recent years reduce the cost and improve the quality of the results for this method. This research explores the methods for applying one of these technologies, vehicle identification systems, with the purpose of OD flow estimation.In this research several location models for vehicle identification systems are presented. These models have better performances comparing to the existing models in the literature. Furthermore, location models for some... 

    Location Finding in Wireless Sensor Network Based on Range-Free Schemes

    , M.Sc. Thesis Sharif University of Technology Nekooei, Mohammad (Author) ; Manzuri, Mohammad Taghi (Supervisor)
    Abstract
    Sensor Localization is a crucial part of many location‐dependent applications that utilize wireless sensor networks (WSNs). Several approaches, including range‐based and range‐free, have been proposed to calculate the position of randomly deployed sensor nodes. With specific hardware, the range‐based schemes typically achieve high accuracy based on either node‐to-node distances or angles. On the other hand, the range‐free mechanisms support less positioning accuracy with less expense. The proposed scheme is based on range‐free localization, which utilizes the received signal strength (RSS) from the anchor nodes. In this work, genetic fuzzy and neuro-fuzzy systems are used to yield more... 

    Modeling Employee’s Preference for Telecommuting

    , M.Sc. Thesis Sharif University of Technology Nowrouzian, Roosbeh (Author) ; Kermanshah, Mohammad (Supervisor)
    Abstract
    This study examines four models of the individual’s preference for home- and center-based telecommuting. Issues concerning the estimation of discrete models when the alternatives are non-exclusive are discussed. Two binary logit models are presented, one on the preference to telecommute from a center versus not telecommuting from a center, and the other on the preference to telecommute from a center over telecommuting from home. A model is also estimated on the following four alternatives: preferring not to telecommute, preferring either form of telecommuting, preferring to telecommute from home, and preferring to telecommute from a center. A comprehensive model of two distinct dimensions of... 

    Determining Variables of Rent to Price Ratio and Efficiency of Housing Market in Tehran

    , M.Sc. Thesis Sharif University of Technology Nafari, Kaveh (Author) ; Fatemi, Farshad (Supervisor) ; Barakchian, Mahdi (Supervisor)
    Abstract
    In this project we tried to examine the effective variables on rent to price ratio and how the variations in R/P influence households’ decisions. Using rent to price ratio, the efficiency of Housing market has been inspected. However, the results for Tehran are in contrast to efficiency assumptions. Moreover, having access to unique database which remarkably increase the accuracy of our estimation, the relation between rent risks and House price has been examined. The results show that rent fluctuations has positive impact on house price. Rent to Price ratio has different applications and we tried to determine the variables that can explain this ratio. Literature review demonstrate that...