Sharif Digital Repository

Hub and Spoke networks come into play when considering direct link between all origins and destinations is either impossible or expensive in a transportation system. In this kind of problems, some nodes are chosen as hub from all origin and destination nodes to collect flows and then distribute them. Implementing hub network leads to minimizing transportation cost, sorting flows and conveying them in economies of scale. Otherwise, shipping flows directly may cause decreasing the travelling distance and the delivery time consequently. In this dissertation, combination of hub network and direct shipment is investigated. To obtain the optimal hub locations and direct links between non-hub nodes... 

Lack of financial sources for production and performing projects has been an effective issue in all governmental and non-governmental organizations. So, using a structure with capability of detecting and forecasting all expenses and costs, and being able to convert the mass of data into useful and instrumental reports for managerial decision such as estimating total cost, selecting the syntax of production and etc is obvious for recourse management of every organization. Among the various components of the cost engineering system, cost management system by recording and allocating cost is an important issue in efficiency of every cost engineering system.In this thesis, Automotive Industrial... 

Control and reduction of gas turbines pollutants emissions are increasingly of major concern. Here we introduce and apply new algorithms for derivation of accurate and low cost skeletal chemical kinetics, optimization of global multi-step chemical kinetics, and optimization of geometry of Lean Premixed (LPM) dry low emission (DLE) combustors.A new reduction algorithm called SA-GEIE, based on sensitivity analysis of reaction mechanisms respect to ignition delay, flame temperature and pollutants concentration (NO and CO), is introduced. This algorithm is implemented to GRI-3.0 to produce a low cost methane oxidation skeletal mechanism with 118 reactions and 39 specie. The accuracy is assessed... 

Emergency Department (ED) overcrowding is one the most problems and challenges that every Emergency Department all over the world is facing with. This problem leads to some problems like prolonged waiting times and Length of Stay in Emergency Department. “Boarding time” is one of the most important ones, which is the time a patient spend for being transferred from Emergency Department to one of the Hospital Inpatient Wards. One important solution to this problem is “overflowing”, and it means allocating patients to an alternative ward rather than their primary ward. In practice, the overflowing process usually controlled in a myopic manner. Limited number of researches that focus in this... 

The advent of Internet and advancement of computer technologies have enabled convenient and fast exchange of multimedia so the illegal reproduction and modification of digital media has become increasingly serious. Hence, how to protect the intellectual property rights of digital multimedia is an imperative issue. Digital watermarking is one of the solutions to prevent unauthorized use of images. Traditional digital watermarking techniques embed a watermark such as logo, trademark, or copyright information into a host image so that it is not perceptible. These techniques, depending on the amount of embedded data, will distort the content of host image which results in quality degradation of... 

A key driver of the overall productivity and profitability of a supply chain is its distribution network which can be used to achieve a variety of the supply chain objectives ranging from low cost to high responsiveness. Designing a distribution network consists of three subproblems: location–allocation problem, vehicle routing problem, and inventory control problem. Because of high dependency among these problems, in the literature there are several papers integrating two of the above problems: location–routing problems, inventory–routing problems, and location–inventory problems.
The three echelon location routing inventori problem (LRIP) is raised by the design of transportation... 

Blind image steganalysis is a technique used to, which require no prior information about the steganographic method applied to the stego im- age, determine whether the image contains an embedded message or not. The basic idea of blind steganalysis is to extract some features sensitive to information hiding, and then exploit classifiers for judging whether a given test image contains a secret message.The main focus of this research is to design an choose features sen-sitive to the embedding changes. In fact, we use high order moments in different domains, such as spatial, DCT and multi-resolution do-main, in order to improve the performance of existing steganalyzers.Accordingly, First, we... 

Software Defined Networking (SDN) is an emerging paradigm which makes the network programmable by separating the control plane from data plane and makes both planes to work independently. There is a centralized controller and a programmable data plane in these networks architecture and forwarding data packets is realized by programming the data plane via an open interface called OpenFlow. OpenFlow is a communication protocol between control and data planes. The centralized architecture of these networks provides a global view of the underlying network to upper applications and brings numerous advantages such as routing, traffic engineering and QoS control. Despite these advantages there are...