Sharif Digital Repository

Increasing the fuel cost and concerns about pollutions have facilitated the use of renewable energies. Wind power as a renewable energy has been considered as a good representative for conventional resources of electrical energy. The biggest obstacles for efficient use of the wind energy are changeability and uncontrollability in wind farm generation and to be far from the demand center. Also, conventional approaches cannot be applied to analyze the effects of this energy on power system. With increment in the penetration of the wind energy in power system, the necessity of considering its effects, especially large scale wind farm, in transmission expansion planning (TEP) studies is... 

This study presents a multi-objective optimization framework for transmission expansion planning in restructured electricity markets under uncertainty considerations. Deregulation of power system has introduced new objectives and requirements for transmission expansion planning problem. Also, the unbundling of electricity industry introduced new uncertainties and escalated the existing ones in network planning. Under these circumstances there is an emerging need for new planning models to cope with restructured electricity industry requirements.The conventional least-cost approaches which represent the transmission expansion planning as a single objective optimization problem could not... 

Optimization methodologies with an emphasis on turbomachinery applications are of great interest. In the present study, a framework is proposed for the multi-objective optimization of a compressor blade using a coupled approximator and optimizer modules, as a mean for lowering the vast computational costs. The proposed framework consists of three main units: a CFD solver, an approximator unit, and an optimizer module. In this regard, a multi-layer perceptron artificial neural network is used as the approximator module while a multi-objective genetic algorithm, the non-dominated sorting genetic algorithm-NSGA II, is employed as the optimizer unit of the framework. In addition, a commercial... 

The multi-facility location-allocation problem is concerned with locating m facilities in the Euclidian plane and allocating n customers to them at minimum total cost. In this work, we focus on a probabilistic version of the problem, in which the locations of the customers and their arrivals are probabilistically distributed. We first formulate the problem as a continuous location-allocation problem. Then, we give an approximated discrete model in which facilities can be located on a set of candidate points. The proposed model has two objective functions which can be calculated only through simulation. Considering the NP-hard nature of the problem and the functions’ unique properties, we use... 

One of the newest approaches in optimization fields under uncertainty which absorb many scientists is robust optimization. This approach uses uncertain data instead of stochastic distributions and its goal is to find a solution which is robust under uncertainty of input data.
Assignment problem is one of the most applicable problems in real world which its parameter is faced uncertainty. Because of this reason, the aim of this thesis is to find a method for solving generalized assignment problem robustly which the coefficients of costs and use of resources by agents for performing the jobs is undetermined. These parameters are interval data and have just lower and upper bound.
For... 

A common decision in project management is the selection of contractors to simultaneously optimize three objectives of the project’s triangle. This issue becomes more important if there is more monetary value involved or there is limited number of capable contractors. In project planning, there is numerous choices for tasks; each with specific time, cost and quality. There is no trade-off problem, if one of the choices has the best time, cost, and quality, simultaneously. However, as these criteria do not generally work in a unique direction, it makes the selection decision difficult. A contractor who performs the projects on time may have higher cost and lower quality. Given that there is a... 

Given the increased competition in supply chains and enlargement of their scale along with increasingly significant role of distribution systems, design and optimization of novel systems with comprehensive approaches in a timely manner has become important more than ever. One of such modern, efficient systems is cross docking in which the distribution network is omitted and thus operations are carried out faster and the productivity is increased. In this system, processes like packaging is done in cross docking and the goods and products are directly sent to customers. This study investigates a long-term and a short-term approach to the design of in two distinct problems. In the first... 

Multidisciplinary Design Optimization (MDO) has been considered by many researchers, especially in field of aerospace engineering during the last two decades. The goal of MDO is to achieve optimal design of systems considering a variety of disciplines. In this regard, selection of viable disciplines, their codification, structure and interactions, levels of integrity and the optimization approach to be utilized are of importance and challenging.
In this project, MDO external ballistic optimization of the conceptual design of a flying projectile is investigated. The key objectives to be met by optimal design were chosen to be maximizing the payload weight and the covered range. To this... 

Most construction projects contain activities repeated in project units or locations with definite consequence. These kinds of projects are called repetitive projects. One of the fundamental objectives of planning and scheduling of repetitive projects is using resources optimally and without interruption, a concept known as continuous workflow. Traditional planning and scheduling methods like Critical Path Method (CPM) are criticized for their disability to produce a reliable workflow. Ignoring the concept of workflow in project schedule causes time and cost overrun that arise from additional waiting times and also increase the risk of accessibility to resources on time. Therefore in this... 

In recent years, economic globalization and resource globalization as two key factors have driven organizations to adjust their processes to survive in the competitive environments. Also, customers have been provided with high-quality products, lower cost, product customization and quick delivery. Moreover, globalization has let suppliers to geographically distribute across the globe, and for accomplishing the final product resources need to be gathered. Distributed infrastructure enables organizations to decrease delivery time and increase flexibility but leads to higher investment costs and lower efficiency of the system. For responding to existing issues Cloud manufacturing has been... 

In this study we addressed the problem of separated waste management. Investigating the literature on location routing problem, reverse logistics, waste management, and countries’ performance in the field, we proposed a novel method for gathering household waste that inspired from prosperous metropolises and took into account the particular situations of developing countries. As a matter of fact, the proposed method is an extension of location routing problem; it’s a bi-echelon network of facilities and multi-compartment vehicles connected via reverse cross docks. The problem is formulated using a mixed-integer linear model with 3 economic, social, and environmental functions; with respect... 

With the rapid proliferation of residential rooftop photovoltaic (PV) systems, current and voltage unbalance issues have become a matter of great concern in low voltage (LV) distribution feeders. This, however, necessitates identification of the hosting phase of the connected single-phase customers and PV panels. Both of the challenges have been addressed in this thesis. In the first place, this thesis proposes a mixed integer linear programming (MILP) model for phase identification problem. The model considers potential error in the input data provided by smart meters. To mitigate negative impacts of the error, the data associated with several consecutive time intervals are taken into... 

Increasing the performance and efficiency of the transportation system is one of the issues that has attracted the attention of many managers and experts in the industrial sector during the last decades, which aims to deliver the product to the customer in the earliest possible time with minimum cost. Therefore, it appears crucial to shed light on two aspects of the issues in this regard. The first one is to create routes functioning as flow transmission interface between many origins and many destinations and to satisfy the allowable time of tours in each route. The other one is the route that vehicles must take within the window time of each destination point. It should be pointed that the... 

This world’s commercial and competitive space force’s designers and manufactures to produce and supply products with high quality and low price at desirable level of reliability. On the other hand, during the design and production process, Engineers are always faced with uncertainty. Essentially, uncertainties can be divided into two categories: aleatory and epistemic. Aleatory uncertainties are due to changes in design conditions, material properties, physical dimensions of components and operating conditions. This kind of uncertainty will not be reduced during the life.on the otherhand, Epistemic uncertainties that are due to lack of knowledge about physical nature of systems can be... 

Supply chain management seeks to coordinate supply chain processes to achieve certain goals; one of which is minimizing the overall cost of the system. In this study integration of different supply chain management decisions i.e. location, routing and inventory management is considered in a single model. The products are distributed in a two-echelon distribution system. One type of product is shipped from a single factory to multiple retailers with deterministic demands through a set of distribution centers. The products can be stored in second and third levels facilities. The product is perishable with a certain shelf life. The product is delivered in a way to be consumed before spoilage. A... 

Optimizing multi-period modern distribution system is a challenging task due to high costs of constructions in urban areas and importance of fast and cheap goods delivery to customers. Various logistic techniques have been proposed to solve this issue. In this study, a new method is suggested to convert the strategic problem of finding depot location into a tactical problem. In addition, a vehicle routing method for multi-period distribution systems in high demand periods have been developed. For modeling this location-routing problem two objective functions have been considered as fallows minimizing the total time in the system to satisfy customer demand and operating costs. To solve this... 

This thesis studies a probabilistic bi-objective location-routing problem that considers multi-product, multi-period system with direct shipment and split delivery which is a case study in SAIPA Group. This model also considers location, allocation and routing decisions in three-level supply chain including factories, distribution centers and customers. Each product for each DC can be supplied by more than one supplier in each period of time, and each factory has a limited capacity. As shortage isn’t allowable, all of the customer’s demand should be satisfied in each period of time. Since customer’s demand could be more than vehicle’s capacity, each customer could be visited more than once... 

This thesis proposes a new non-linear multi-objective Location-Inventory-Routing problem (LIRP( for perishable products considering multi trips for vehicles. Managing the expiration date of perishable products, speed of vehicles in the system, the frequency of using the vehicles and etc. bring complexity in LIRP in this problem.
First objective focuses on maximizing profits calculated by Incomes of selling goods with different worthwhile depend on their remained life time and costs of inventory and distribution as well as ordering. Minimizing CO_2 emmition as the environmental issue has been considered as the second objective. Third objective which is minimization of injury rate,... 

Persian Gulf with 21 Iranian islands and various ports from Makran’s coast in the south east of the country to Khorramshahr port in the southwest with significant potential for promotion of tourism industry and transportation of marine passengers between the coastal provinces of the country and the neighboring countries of the southern border of the Persian Gulf. The shipping of the sea includes different types of floats with different passenger capacities and strokes that the floating right selection is appropriate to the type of trip and the number of passengers which including the various costs.In summary, what we are looking for in this research are:
1.Select location or locations as... 

Technological progress, complexity in costumers’ needs and distributed resources make extreme competition in business environment. It produces some novel concepts. In this research, we concentrate on cloud manufacturing which was generated by using cloud computing concepts and focuses on resources sharing between various manufacturers. One of key problems in this field is service composition. In this work, I have proposed a mathematical model with binary variables for service composition problem in multi-cloud manufacturing environment. In this model, I’ve considered for qualities of services (cost, time, energy, reliability) as objective functions. Cost and time functions include the cost...