Sharif Digital Repository

In this research, we present a new method for solving layout problems in the cellular manufacturing system. We also analyze the transportation systems using automated guided vehicles (AGVs) and its cost affecting the performance of cellular manufacturing system. For elimination of inter current and traffic problems, we use a new idea of dividing workstations to some non-overlapping closed zones to which independent automated guided vehicles (AGVs) are allocated for internal transfers in each zone. In this research, a combinational mathematical model has been developed for minimizing the cost of material flow intra and inter-loops and minimization of procurement of AGVs for each zone while... 

The aim of the present research is to examine improving the technology in terms of technical and engineering dimensions and also assessing their long-term economic & social advantages. The population of the research consists of top managers, middle managers and technical experts working in power plants situated in the west of Iran (Kermanshah, Kurdistan and Ilam). According to the research aims, this research is a practical survey trying to explore a model consistent with the subject of research, i.e. improving the condition of technology in electronics industry. The utilized instrument in this research is a questionnaire with a reliability level equal to (α = 0.754.) The validity and... 

This research presents a modified algorithm for constrained optimization of random simulation models. One output is selected as objective to be minimized, while other must satisfy the given threshold value. Moreover, the simulation inputs must be integer and satisfy linear or nonlinear constraints. The research applies a sequentialized experimental design to specify the simulation input combinations, Kriging (or spatial correlation modeling) to analyze the global simulation input/output data resulting from these designs, and nonlinear programming to estimate the optimal solution from the Kriging metamodels. In addition, a simulation model is developed for different inventory planning... 

Transportation problem is one of the most important parts in supply chain management and it offers great potential to reduce costs and improve service quality. So many research efforts, are considering the optimization of the transportation systems and its related aspects. In this thesis, a transportation system according to a real case study, with the aim of minimizing total cost is considered. It is assumed a fleet of vehicles with limited capacity and different fixed and variable costs are shipping different products from a manufacturing plant to their associated nationwide distribution storages. Certain number of storages or depots with deterministic demand is available and each has a... 

Digital computer simulation and employing the concepts of the experimental design, and other analytical tools for evaluating its output have attracted many of the scientists and researchers interests in the recent decades. The importance of this topic has been increasing and more related analytical tools have been introduced to the scientific literature. One of the powerful tools for simplifying accelerating the optimization process of simulation results, are the use of the metamodels. Use of these powerful tools becomes more eminent when the simulation runs are expensive. By the use of the metamodels the needs of conducting sampling for obtaining some more new points from direct simulating... 

In the last two decades, Supply Chain Management has become an integral part of sciences such as Management and Industrial Engineering. A key issue in this concept is how to coordinate the activities of the members of the chain in order to improve the performance of the whole system. In this thesis, the main concentration is on production, pricing and lot-sizing policies in a two-stage supply chain with a producer and a retailer. The producer manufactures the final product and vends it to the retailer, and the retailer sells it to the final customer. The customer’s demand is under iso-Elastic pattern that is one the four most popular price-sensitive demand functions. Moreover, in attempting... 

The concept of Enterprise Resource Planning (ERP) has been the center of attraction for manufacturing firms. So many of these firms have dedicated their efforts in implementing this concept. The high competition among these firms leads to use ERP very seriously. Implementation of ERP concepts has major efforts of daily activities of these firms and it can be stated that : "Without use of the ERP concepts manufacturing firms cannot survive" Hospital activities are not very different from manufacturing activities in nature. Despite of this similarity, very limited efforts have been dedicated to implement ERP concepts in the hospital. The goal of this thesis is to design a conceptual model for... 

simulation models are free of any restricting assumptions which may normally be considered in a stochastic system, so simulation is considered as one of the most popular tools that can be applied toward analysis of behavior of stochastic systems which are complex.
In order to analyze such problems and determine the best combination of input variables to optimize the system performance criterion, simulation optimization methods were introduced. The most important issue in these problems is that simulation models are usually considered as the black-box models in which, the output function is not usually expressed explicitly.
This work reviews different methods which developed... 

Distribution network is a part of the country’s economic that its structure is affected by economic evolutions. Improper operation and irrational structure of distribution system increases the price of goods and services and creates discontent and makes unreasonable expectations in producers and consumers. In addition, it causes severe fluctuations of price, loses of resources, lack of clarity, reduction of purchasing power, turmoil in market operation, and creation of unofficial distribution networks in society. This investigation focuses on analysis of distribution part of dairy products and tends to evaluate prices and presents solutions to reform prices of distribution. This research... 

Minimizing completion time of tasks in a flowshops has always attracted attention of researchers since it was introduced by Johnson, 1954. If all jobs are processed in the same order, the sequence is called a permutation sequence. Tardiness factor is one of important factors in permutation flowshop sequencing problem. Minimizing this factor brings about increase in service level of the shop and is helpful in meeting customer’s needs. Since, minimizing tardiness in PFSP in among NP-hard problems, computational efforts in this area has focused on heuristic approaches. However, the researches has always considered due dates only on the last machine. It means, always it has been assumed that due... 

As you know in lean supply chains, it is tried to: reduce the wastes of resources and achieve more production with lower consumption of resources. This system is very well suited for many supply chains in which the final determinant factors are price and quality. In contrast, recently, the concept of agile supply chain has been introduced, insisting on flexibility and high service level. Opposite to lean supply chain, agile supply chain needs safety stock to be able to respond to market’s changes.
Regarding the dissimilarities of these models –including the disagreement in the allocation of safety stock to nodes– In this thesis, in addition to studying and comparing these two approaches,... 

Nanotechnology requires a number of infrastructures for reaching its sustainable development. For each step of its development , various infrastructures should be studied and prepared in advance.In this direction, by introducing and recognizing the priority of Iran Nanotechnology R&D indexes ,the present research is going to propose an effective help. In this case, after studying the related literature and gathering the needed data , 27 indexes were recognized. Then , the indexes were divided in 7 criteria.In order to find the priority of the applied indexes , Fuzzy Multiple Criteria Decision Making (FMCDM) was applied. As the weighting of 7 criteria had been found by FANP , the... 

Today, with advances in technology and communication equipments, supply chain management plays an important role in different industries. Bullwhip effect is the significant factor which can reduce efficiency of supply chain and increases costs and lead time of services and products to the ultimate customer. In this thesis we have investigated on forecasting method and ordering policy in the bullwhip effect. Basic model based on beer game, moving average, Holt and Brown are 4 models which were studied. Also we defined desired stock and desired stock line which the difference between desired and actual stock and also difference between desired and actual stock line in any period, have... 

Multi core processors are becoming mainstream in the computation area, wide application of multi core processors in Engineering, Industrial purposes and scientific applications made them popular among users and Manufacturers, cloud computing is a very well known Concept which technically is a Multicore processing environment, most of Businesses, enterprises and engineering works nowadays are getting done by the help of cloud services, hence, to get the best of these multi core cloud computing systems, scheduling of the tasks on the cores and virtual machines(VMs) is necessary, which is the answer to two questions: each task must be assigned to which core(VM)? And What is the order of... 

The traveling salesman problem consists of a salesman and a set of cities in which the salesman has to visit each one of the cities only once, starting from an arbitrary city and returning to the same city. The challenge of the problem is that to find a trip to minimize the total length of the tour.The Travelling Salesman problem is a well-known and important combinatorial optimization problem. Despite this simple problem statement, solving the TSP is difficult since it belongs to the class of NP-complete problems. Due to its computational complexity, recent researches suggest that meta-heuristic approaches can be the best solution approach for the general form of this problem.This thesis... 

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... 

This research aimed to develop materials that can degrade organic pollutants and industrial dyes in water under visible light irradiation. In this study, an efficient material was prepared by combining bismuth tungstate (Bi2WO6), an organic polymer semiconductor called g-C3N4, and a metal-organic framework MIL-100(Fe). This combination was designed to have optimal performance in light absorption and pollutant degradation. A simple hydrothermal method was used to fabricate this material, which resulted in the formation of a ternary structure with specific properties. This structure includes bonds through which electrons generated when light is irradiated are rapidly transferred to different...