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optimization
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Optimal Scheduling in Wirelessly-powered Communication Networks
, Ph.D. Dissertation Sharif University of Technology ; Pakravan, Mohammad Reza (Supervisor)
Abstract
In this thesis, we study optimal scheduling in a multi-hop wirelessly-powered network. We propose an online control policy for energy transfer from the energy access point to the wireless nodes and for data transfer among the nodes. With our proposed control policy, all data queues of the nodes are stable, while the average energy consumption of the network is shown to be within a bounded gap of the minimum energy required for stabilizing the network. Our proposed policy is designed using a quadratic Lyapunov function to capture the limitations on the energy consumption of the nodes imposed by their bachery levels. We show that under the proposed control policy, the bachlog level in the data...
Binding Energy of Multi-Partite Quantum Systems based on Quantum Thermodynamics Viewpoint
, Ph.D. Dissertation Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Rezakhani, Ali (Supervisor)
Abstract
Examining composite quantum systems through quantum thermodynamics, we face the new concept of binding energy. In this thesis, we are going to present a general definition for binding energy in quantum systems which covers any kind of interactions. First of all, we examine the possibility of energy exchange in a quantum system using quantum thermodynamics. In this theory, energy exchanges of an open quantum system may be divided in to two portions: heat and work; due to an accepted definition, heat is the portion of energy that is supposed to change entropy, while work has no influence on that. In this research, we restrict our calculations to the systems which are thermally closed and...
Graph Learning from Incomplete and Noisy Graph Signals
, M.Sc. Thesis Sharif University of Technology ; Babaiezadeh, Masoud (Supervisor)
Abstract
The problem of inferring a graph from a set of graph signals over it plays a crucial role in the field of Graph Signal Processing (GSP). When provided with a graph that best models the structure of data, the GSP algorithms can offer high data processing capability. However, a meaningful graph of data is not always available, hence in some applications, the graph needs to be learned from the data itself. When the data is corrupted and missing, this task becomes even more challenging. In this paper, we present a graph learning algorithm that is capable of learning the underlying structure of data from an incomplete and noisy dataset of graph signals. We propose an algorithm that jointly...
An Optimization Model for Shared Electric Vehicle Routing Problem in Urban Trips
, M.Sc. Thesis Sharif University of Technology ; Shafahi, Yousef (Supervisor)
Abstract
In today’s world, people’s tendency to use their own vehicles is relatively high since private cars provide more convenience, better safety, and better time management than public transportation, but cause more traffic in the streets. Ride-sharing is one of the management tools that has attracted a lot of attention in recent years to mitigate the traffic congestion. Also, electric vehicles are used for public transportation in many parts of the world to achieve a sustainable environment. In this study, we assume that passengers’ origin, destination, and preferred time windows for pick-up and drop-off are known in advance. The aim of the study is to determine the sequence of visiting travel...
Integration of Production-inventory-routing Problem with Simultaneous Pickup and Delivery and Robust Optimization Approach
, M.Sc. Thesis Sharif University of Technology ; Akbari Jokar, Mohammad Reza (Supervisor)
Abstract
PRP is a combination of two classic problems. First one is the lot-sizing and the second one is vehicle’s routing which have been studied for more than fifty years. The prp is solved in attempt to jointly optimize production, inventory, distribution, routing decision and as a result, it is a inventory-routing problem as a whole. Despite the fact that prp involves a complex instructor, both universities and industries have been so eager to this problem since last decade. In this thesis an integrated assessment of PRP and various technics for solving the problem have been discussed. Moreover, taking into account the structure, hypothesis, and the constraints of the problem, a...
Reduction of Development Cycle Time using Integrated die Design Technology
, M.Sc. Thesis Sharif University of Technology ; Houshmand, Mahmoud (Supervisor)
Abstract
In today’s industrial world production is considered as a competitive weapon. This has caused many companies active in this field to move towards creating competitive advantage to reduce costs of design, construction and increase production. In particular molding as one of the main industries is among the most economical technological resources of each country. About 50 to 70 percent of the price of a production operation is spent of the strip of sheet by pressing; thus the proper design of a strip of sheet has a great impact on the mold design. Today, in most sectors of the industry there is a need for cutting and packaging of products and form molding and glass cutting to fitting the...
An Applied Model for Highway Alignment Optimization Using Particle Swarm Optimization Method
, M.Sc. Thesis Sharif University of Technology ; Shafahi, Yousef (Supervisor)
Abstract
A basic highway design problem is to find the most economical alignment connecting two given end points based on topography, soil conditions, socioeconomic factors and environmental impacts, while satisfying a set of design and operational constraints. The cost function complexity and numerous limitations such as highway design criteria have made this problem a NP-hard one. In this study, a swarm based searching algorithm has been applied to a three dimensional highway alignment optimization model. The spatial data has been exploited from a GIS databases using a heuristic swift approach. In addition, the majority of cost items that depend on highway design have been extended in a practical...
A Robust CVaR Model under Uncertainty for IMRT Treatment Planning
, M.Sc. Thesis Sharif University of Technology ; Najafi, Mehdi (Supervisor) ; Rafiee, Majid (Co-Supervisor)
Abstract
Nowadays, radiation therapy is one of the most common methods for the cancer treatment. Intensity Modulated Radiation Therapy(IMRT) is a novel technique of radiation therapy that aims to delivere sufficient dose to cancerous tissues while sparing healthy organs. There are various uncertainties in radiation therapy problems, including uncertainty about device setup, device errors, interfraction and intrafraction motions. One of the most important uncertainties is the movement of the tumor during the treatment process(intrafraction motion), as this displacement may cause the cancer tissue to not receive sufficient dose and also to damage the healthy tissue due to a violation of their dose...
A Mathematical Model to Optimize the Logistic Activities in Response Phase of Earthquakes
, Ph.D. Dissertation Sharif University of Technology ; Eshghi, Kourosh (Supervisor)
Abstract
reparedness and emergency procedure be devised in the event of,and prior to,a disaster. One of these disastersoften accompanying byhuge damages, losses and casualtiesisanearthquake. After such a disaster, several governmental and non-governmental organizations usually start relief operations. They commonly pursue their own agendas and use their own facilities and capabilities to help the people affected without pursuing a central plan. These disintegrated behaviors of involved organizations generate contradictory responses and result in either wasted resources or preventing equitable service for all affected people. Due tothe abovefact, this dissertation proposes amodel for improving...
A Land Use-Transportation Model with Optimal Strategy Algorithm for Evaluating Transit-Oriented Development Decisions
, M.Sc. Thesis Sharif University of Technology ; Pourzahedi, Hossein (Supervisor)
Abstract
There is a two-way relationship between land use and transportation. So each of them can be used to manage and control the other one. Land use can be Auto-Oriented, or Transit-Oriented. Auto-Oriented Development leads to urban sprawl, causing longer trips and increasing use of private cars. Problems related to this type of development appeared by the end of the 20th century. On the other hand, Transit-Oriented Development may lead to higher density areas, and higher transit use, providing better space for pedestrians and cyclists, as well as increasing environmental pollutions. Land use-transportation relationship hs been the subject of many recent studies. One of the previous models...
An Optimization Model for the Time-Dependent Electric Vehicles Routing Problem in Shared Travel
, M.Sc. Thesis Sharif University of Technology ; Shafahi, Yousef (Supervisor)
Abstract
People are increasingly using private vehicles as a result of the ever-increasing population growth worldwide and the increasing number of travel requests through the transportation network. There are many problems associated with the use of private vehicles on the transportation network, including traffic congestion and air pollution. To address the existing demand, decision-makers have always sought effective modes to respond to the existing situation. For passengers, the proposed modes of transportation should offer the same level of convenience and affordability as a private vehicle. In recent years, shared mobility has become increasingly popular. This mode of transportation has...
A Mutual Predictive Scheduling Model for Customer Order Prioritizing & Manufacture Scheduling Inspired by Industry 4.0
, M.Sc. Thesis Sharif University of Technology ; Fatahi Valilai, Omid (Supervisor)
Abstract
This study, with integrated approach to the POM problem, has developed a linear mutual MILP model with the hybrid MTS / MTO operational approach on the OAS problem in industry 4.0 environment for the Shahin Plastic Manufacturing Company. This enabled an integrated PM with the production in the scheduling model. The model objective function has minimized costs and maximized the company profits. It also maximized customer satisfaction by minimizing the tardiness and earliness time in producing orders. To implement this model in the factory decision-making system, measures and modifications have been made to the MIS structure of the corporate departments. Measures include the creation of cloud...
An Integrated Multi-criteria Decision Making Approach for a Sustainable Supply Chain Network Design
, M.Sc. Thesis Sharif University of Technology ; Shavandi, Hassan (Supervisor)
Abstract
Growing concerns towards social and environmental issues besides economic in supply chain causes that the sustainable supply chain become one of the most important concepts in a supply chain. Likewise, a supply chain network design which is profound influence on long-run economic, environmental, and social decisions is one of the key and strategic topics in a supply chain. In this study, we represent an integrated approach for a three-layer sustainable supply chain network design with routing and different transportation modes, the objectives of which are minimizing total costs, a minimizing 〖CO〗_2 emissions of transportation, and maximizing total values of social purchasing. In this...
A Robustification Approach in Unconstrained Quadratic Optimization
, M.Sc. Thesis Sharif University of Technology ; Peyghami, Mohammad Reza (Supervisor) ; Fotouhi Firouzabad, Morteza (Supervisor)
Abstract
In this thesis, unconstrained convex quadratic optimization problems subject to parameter perturbations are considered. A robustification approach is proposed and analyzed which reduces the sensitivity of the optimal function value with respect to the parameter. Since reducing the sensitivity and maintaining a small objective value are competing goals, strategies for balancing these two objectives are discussed. Numerical examples illustrate the approach
A Machine Learning-Based Hierarchical Risk Parity Approach for Portfolio Asset Allocation on the Tehran Stock Exchange
, M.Sc. Thesis Sharif University of Technology ; Habibi, Moslem (Supervisor) ; Fazli, Mohammad Amin (Co-Supervisor)
Abstract
The process of portfolio construction and optimization can be broken down into three main steps: selecting appropriate assets, allocating capital, and monitoring and adjusting the portfolio. This study focuses on evaluating the performance of the Hierarchical Risk Parity (HRP) method for capital allocation in investment portfolios, specifically in Iran’s capital market. The aim is to enhance the method's effectiveness by implementing alternative correlation calculation approaches, such as Wavelet and Chatterjee correlations. The study utilizes three different portfolios containing assets from the Tehran Stock Exchange, the US stock market, and the cryptocurrency market. The primary objective...
A Robust Conditional Value-at-Risk (C-VaR) Optimization Approach for Direct Optimization of Beam Directions and Apertures in Intensity Modulated Radiation Therapy Method
, M.Sc. Thesis Sharif University of Technology ; Eshghi, Kourosh (Supervisor)
Abstract
Breast cancer has been one of the main causes of women's deaths in recent years. Today, various methods are used to treat this disease, among which intensity-modulated radiation therapy is one of the most common methods. The goal of radiation therapy is to destroy cancer cells while protecting the surrounding healthy tissues. In left breast cancer, due to the proximity of the heart and breast tissue, we are at risk of delivering an excessive dose to the heart and increasing cardiac complications after the treatment. In addition, due to the irregular and unpredictable breathing movements of the patient during the treatment and the resulting uncertainty, we face more challenges. In order to...
A Proximal Method for Composite Minimization
, M.Sc. Thesis Sharif University of Technology ; Mahdavi-Amiri, Nezamoddin (Supervisor) ; Soleimani-damaneh, Majid (Supervisor)
Abstract
We consider composite minimization problem of the form minx h(c(x)), where the function c : Rn ! Rm is smooth and the function h : Rm ! [+1;1] is usually convex or prox-regular, but may be nonsmooth. A wide variety of important optimization problems fall into this framework, and so far several studies have been done in this regard. One of these studies relates to the condition that the function h is finite convex and the algorithm uses a line search method. Another case is solving nonlinear programming problems using a penalty function where the function h is finite polyhedral. Research has also been done for the case where the function c is identity, that is c(x) = x.We describe an...
An Inexact Newton Method for Nonconvex Equality Constrained Optimization
, M.Sc. Thesis Sharif University of Technology ; Mahdavi Amiri, Nezamoddin (Supervisor)A Filter-Trust-Region Method for Simple-Bound Constrained Optimization
, M.Sc. Thesis Sharif University of Technology ; Mahdavi Amiri, Nezameddin (Supervisor)
Abstract
We explain a filter-trust-region algorithm for solving nonlinear optimization problems with simple bounds recently proposed by Sainvitu and Toint. The algorithm is shown to be globally convergent to at least one first-order critical point. We implement the algorithm and test the program on various problems. The results show the effectiveness of the algorithm