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Integrated Pricing and Queuing Problem

, M.Sc. Thesis Sharif University of Technology Goodini, Kambiz (Author) ; Shavandi, Hasan (Supervisor)

Abstract

Joint price and service capacity decisions and integrated pricing and queuing problems with finite or infinite buffers are two remarkable issues of pricing research. In this thesis we consider a joint price and service capacity determination problem in a single server, finite buffer queuing system. Customers arrival and serving occur as Poisson processes. Because of finite buffer capacity, customers finding the system full upon their arrival would be rejected. Customers differ with respect to their reservation prices and time sensitivities. This study focuses on investigating the effect of finite buffer capacity and customers reservation prices and time sensitivities on optimal policy and...

Application of Pricing in Flowshop Scheduling

, M.Sc. Thesis Sharif University of Technology Yarali, Safar (Author) ; Shavandi, Hasan (Supervisor)

Abstract

This research considers coordination of pricing and scheduling decisions in a make-to-order environment. We consider a two machine flowshop environment. The objective is to maximize the total net profit, i.e. revenue minus scheduling cost resulting from pricing and scheduling decisions. Prices of orders are set by the manufacturer and demand is a non-increasing function of price. Two mixed integer linear programming models have been developed for the research problem. As the problem is shown to be NP-Hard, a Metaheuristic algorithm is developed which is combination of two tabu search sub algorithms, one for pricing and the other for scheduling. And to evaluate performance, results from...

Distribution Problem in Heterogeneous Networks with the Assumption of Flexibility in the Delivery of Goods

, M.Sc. Thesis Sharif University of Technology Fakhimi, Ramin (Author) ; Shavandi, Hasan (Supervisor)

Abstract

In this research, we consider a network of distiribution channels and a central warehouse to deliver the products to distribution centers. We assume the price of products are fixed and the central warehouse is authorized to change the delivery amount for each DC in a reasonable interval. The main idea is authorizing the central warehouse to be flexible in delivery of ordered amounts of DCs in a reasonable interval in order to reduce the transportation cost and then maximizing the profit.
The problem is formulated as a linear integer programming model and the properties of optimal solution is analyzed. Based on the properties of the model a solution algorithm is developed to solve the...

Geometrical Optimization of Traction Infinitely Variable Transmission for Minimizing of Rollers Deformation

, M.Sc. Thesis Sharif University of Technology Afzali, Abolfazl (Author) ; Zohoor, Hasan (Supervisor)

Abstract

With intensified concerns of rising fuel vehicles that reduce fossil fuel globally and also prescript strict rules by standard institutes, vehicle manufacturers try to find a way for reducing the fuel of their products. One these methods use a continuously variable transmission (CVT) instead of manual and automatic gearboxes. Various CVT’s have been proposed in recent year.
One of the proposed systems is traction infinitely variable transmission (TIVT) that is type of traction drive continuously variable transmission and has been presented in 2007. Research on this system showed that average efficiency is about 96% that is high efficiency. Completed research in 2011 showed that despite...

On The Non-Linear Behavior of Continuous Beam to Column Connection

, M.Sc. Thesis Sharif University of Technology Rahmani, Ahmad (Author) ; Moghadam, Hasan (Supervisor)

Abstract

A special steel beam-to-column connection, named Khor-jini, is commonly used for steel framing system in Iran. In this system, two continuous beams are passed next to the columns and are connected to the column side using seated brackets.This type of connection has been common in Iran from the late past. Unfortunately, the seismic behavior of Khorjini frames had not been sufficiently studied prior to Manjil Earthquake of 1990. Due to very large damages which occurred in steel structures especially in connections during the said earthquake, the seismic behavior of this type of connection was studied and some of its weak points were recognized.In this study non-linear...

A numerical investigation on the cure cycle of composite brake blocks

, Article International Polymer Processing ; Volume 21, Issue 4 , 2006 , Pages 421-431 ; 0930777X (ISSN) Shojaei, A ; Sharif University of Technology

Carl Hanser Verlag 2006

Abstract

Composite friction materials used in the braking system of vehicles are composed of different ingredients (typically up to 20 materials). The overall physical properties of these products are determined by the type and percentage of the individual ingredients in the final composition and consequently, may differ from one product to another. This paper studies the cure characteristics of railroad composite brake blocks during compression molding. Numerical simulations using the control volume/finite element method (CV/FEM) are utilized to predict temperature fields and cure conversion during the process. As railroad brake blocks are normally thick-sectioned parts, a three-dimensional modeling...

Numerical simulation of three-dimensional flow and analysis of filling process in compression resin transfer moulding

, Article Composites Part A: Applied Science and Manufacturing ; Volume 37, Issue 9 , 2006 , Pages 1434-1450 ; 1359835X (ISSN) Shojaei, A ; Sharif University of Technology

2006

Abstract

In compression resin transfer moulding (CRTM), resin flows inside a mould filled with fibrous reinforcement as a result of resin injection and mould compression. This process facilitates the resin flow through the fibrous reinforcement particularly for high fiber content parts. This paper presents the numerical simulation of filling process of CRTM in full three-dimensional domain. A mathematical model of three-dimensional resin flow inside the CRTM mould is presented. An effective elastic modulus is introduced for multi-layer preforms connecting the mould closing speed to deformation rate of individual layers. Control volume/finite element method (CV/FEM) is used and the numerical algorithm...

A numerical study of filling process through multilayer preforms in resin injection/compression molding

, Article Composites Science and Technology ; Volume 66, Issue 11-12 , 2006 , Pages 1546-1557 ; 02663538 (ISSN) Shojaei, A ; Sharif University of Technology

2006

Abstract

In resin injection/compression molding (RI/CM), a preform often comprises layers of different fiber reinforcements. Each fiber reinforcement has unique through thickness and in-plane permeabilities as well as compressibility, creating a heterogeneous porous medium in the mold cavity. In the present article, numerical simulation is utilized to investigate the filling process of RI/CM in such a heterogeneous porous medium. The filling stage is simulated in a full three-dimensional space by using control volume/finite element method and based upon an appropriate filling algorithm. The flow in the open gap which may be present in the mold cavity is modeled by Darcy's law using an equivalent...

Pricing and Lead Time Decisions in Decentralized Supply Chains Under Competition

, M.Sc. Thesis Sharif University of Technology Afzalabadi, Maryam (Author) ; Shavandi, Hasan (Supervisor)

Abstract

This thesis investigated a two-echelon supply chain consists of one retailer and several manufacturers that faces a price and lead time sensitive demand. We use a Stackelberg game for decision analysis of prices and lead times determined by manufacturers as Leader and retailer as a Follower. We assume that demand depends to the retailer’s price. Market share of each manufacturer, is also price and lead time sensitive. Objective of each firm is to determine price and planned lead time to maximize her own profit. We first determine the best response of the retailer to manufacturers’ decision and next at manufacturers’ level, we will solve the problem for one manufacturer at first and then we...

Source Enumeration and Identification in Array Processing Systems

, Ph.D. Dissertation Sharif University of Technology Yazdian, Ehsan (Author) ; Bastani, Mohammad Hasan (Supervisor)

Abstract

Employing array of antennas in amny signal processing application has received considerable attention in recent years due to major advances in design and implementation of large dimentional antennas. In many applications we deal with such large dimentional antennas which challenge the traditional signal processing algorithms. Since most of traditional signal processing algorithms assume that the number of samples is much more than the number of array elements while it is not possible to collect so many samples due to hardware and time constraints.
In this thesis we exploit new results in random matrix theory to charachterize and describe the properties of Sample Covariance Matrices...

Design of Three Fingered 5 –DOF Hand for Laparoscopic Surgery

, M.Sc. Thesis Sharif University of Technology Masoumnia, Adel (Author) ; Zohoor, Hasan (Supervisor)

Abstract

Today, many surgical procedures such, gallbladder, gastric bypass, placement of a ring around the stomach, partial removal of colon, removal of tumors use laparoscopic techniques. In this surgery, a variety of tools to capture and remove the internal organs can be used. Sometimes the surgeon selects the proper tools and replacement during surgery, so the surgeon had to do different things with the operation. These tools generally cannot be used because of the large internal organs device is small and does not have enough degrees of freedom. In laparoscopic surgery, the surgeon operate in the abdominal cavity using a thin instrument that is inserted through the trocar hole would do. If...

Thermal stresses and kinetics of phase transformation on the run-out table after hot strip rolling of low-carbon steels

, Article International Journal of Advanced Manufacturing Technology ; Volume 83, Issue 9-12 , 2016 , Pages 1725-1736 ; 02683768 (ISSN) Hasan Nasab, M ; Serajzadeh, S ; Sharif University of Technology

2016

Abstract

A thermo-elastic analysis coupled with a phase change model is employed to evaluate thermal stresses as well as progress of austenite decomposition after hot strip rolling operations. The thermo-mechanical finite element analysis is utilized to assess the distributions of temperature and thermal stresses during cooling while at the same time, a model based on the additivity rule is used to determine the rate of austenite to ferrite decomposition. The proposed model is applicable to multi-pass rolling schedules while the effects of different process parameters including the rolling speed and cooling configuration of the run-out table can be taken into account. In order to verify the...

Water and emissions nexus for biodiesel in Iran

, Article Renewable and Sustainable Energy Reviews ; Volume 93 , 2018 , Pages 354-363 ; 13640321 (ISSN) Haj Hasan, A ; Avami, A ; Sharif University of Technology

2018

Abstract

Biodiesel is an attractive renewable energy in Iran. However, the concerns for food security, emissions, and water requirement move us towards developing the analytical framework to study emission-water nexus of biodiesel via the multi objective sustainable planning of biodiesel supply chain. Here, the literature of biodiesel in Iran is comprehensively reviewed and main issues are discussed. Then, a supply chain planning model is applied to depict the optimal path ways to minimize costs, net emission, and water use in Iran during 25 years. The microalgae via open ponds and jatropha cultivation reduce the total costs and improve negative emissions. The jatropha optimizes the water use and...

Comparative assessment of bioethanol supply chain: insights from Iran

, Article Biofuels ; 2018 ; 17597269 (ISSN) Haj Hasan, A ; Avami, A ; Sharif University of Technology

Taylor and Francis Ltd 2018

Abstract

Biofuels are important alternative fuel in recent years. In this work, the bioethanol supply chain planning is performed by BioEnergy Supply Model to optimally find the best pathways using economic and environmental objective functions in Iran. Then, different sustainability criteria focusing on environmental, economic, and social concerns are assessed for possible routes of the bioethanol production from available resources. Although agriculture residues and wastes, decrease the greenhouse gas emissions but municipal solid wastes are more economic and require less water. The agricultural wastes and residues improve the sustainability. Then, criteria focusing on environmental, economic, and...

Comparative assessment of bioethanol supply chain: insights from Iran

, Article Biofuels ; Volume 12, Issue 4 , 2021 , Pages 475-483 ; 17597269 (ISSN) Haj Hasan, A ; Avami, A ; Sharif University of Technology

Taylor and Francis Ltd 2021

Abstract

Biofuels are important alternative fuel in recent years. In this work, the bioethanol supply chain planning is performed by BioEnergy Supply Model to optimally find the best pathways using economic and environmental objective functions in Iran. Then, different sustainability criteria focusing on environmental, economic, and social concerns are assessed for possible routes of the bioethanol production from available resources. Although agriculture residues and wastes, decrease the greenhouse gas emissions but municipal solid wastes are more economic and require less water. The agricultural wastes and residues improve the sustainability. Then, criteria focusing on environmental, economic, and...

Designi an Adaptive Beamforming Algorithm, Robust Against Direction-of-Arrival Mismatch

, M.Sc. Thesis Sharif University of Technology Rahmani, Mostafa (Author) ; Bastani, Mohammad Hasan (Supervisor)

Abstract

Adaptive beamforming performance is very sensitive to any mismatch between actual and presumed steering vectors of desired signal. In addition to this sensitivity, presence of desired signal in training snapshots dramatically reduces the convergence rate, as compared to the case that signal-free training snapshots are available.
The present work is aimed at proposing a new adaptive beamformer that is robust against direction-of-arrival (DOA) mismatch and has high convergence rate. This method is based on desired signal elimination from training snapshots and sub-array beamforming technique. To this end, a Blocking matrix that converts primary data to desired signal free data is...

Transfer Pricing in Multinational Firms with Vertical Differentiation

, M.Sc. Thesis Sharif University of Technology Taefi Aghdam, Niloofar (Author) ; Shavandi, Hasan (Supervisor)

Abstract

For Organizations that intend to do their various activities in the form of separate and independent units, precise information about the profits or losses of each unit is very important. One of the most important factors required to determine the profitability of units and their performances, is the price at which goods and services are exchanged amongst units. The value assigned to these transactions and events is called "transfer price". As these transfers occur within the organizations, and they heavily affect the performance evaluation of managers of different parts of the organization, their valuation must be performed with sufficient insight.
This paper examines the impact of...

?Euthanasia, Yes or No

, M.Sc. Thesis Sharif University of Technology Hoseini, Safieh Sadat (Author) ; Hoseini, Hasan (Supervisor)

Abstract

Euthanasia is one of the most controversial topics in medical ethics and in the areas of religion, law and ethics are studied .Different approaches to the authorities in case of euthanasia on the ballot, specifically rooted in the philosophical approach, to their beliefs and culture. According to the above description. The main objective of this paper is to study the philosophical approach of euthanasia. Therefore, this text answer three main questions. The first question will be discussed in the first chapter is that "How general philosophical issues applied to specific cases such as euthanasia?" The second question is about the definition and types of euthanasia .This question will be...

Numerical Investigation of Bidirectional Swirl Flow’s Structure in Vortex Engine

, M.Sc. Thesis Sharif University of Technology Mehrdad, Mohammad (Author) ; Saidi, Mohammad Hasan (Supervisor)

Abstract

Numerical investigation of flow field and determination of velocity components in swirl flow are novel and important subjects in combustion chamber of swirl flow. The exact understanding of vortex phenomena and flow structures in vortex engine results in better design and control in terms of stability, geometry, cooling, and combustion efficiency. Although, numerical approaches are computationally complex, they are worthwhile and efficient. The aim of this work is to study the velocity field in a bidirectional swirl flow within the combustion chamber using numerical approaches. The investigation of flow field has been performed in the cold chamber. Four different models (RSM and LES) have...

A Novel Model for Three-Dimensional Imaging Using Interferometric ISAR in Curved Target Flight Paths

, Ph.D. Dissertation Sharif University of Technology Nasirian, Mahdi (Author) ; Bastani, Mohammad Hasan (Supervisor)

Abstract

A Synthetic Aperture Radar (SAR) is a system which collects the received signal from a ground target area along linear motion of a flying vehicle carrying it, in order to provide a very high resolution 2D image of it. In Inverse SAR (ISAR), the radar is fixed on the ground and the data collection is performed along the linear motion of the aerial target. Using a second receiver antenna close to the main transceiver antenna of ISAR, it is possible to make a three-dimensional (3D) image of the target, or equivalently find the 3D coordinates of the target scattering points. Such system is called bistatic, monopulse or interferometric ISAR (InISAR). In the conventional model of ISAR, the flying...