Light Duty Vehicles' Emission Reduction Potentials in Megacities
Using New Powertrain Technologies (Case Study: Tehran)

, M.Sc. Thesis Sharif University of Technology Askariyeh, Mohammad Hashem (Author) ; Erhami, M. (Mohammad) (Supervisor) ; Pourzahedi, H. (Hossein) (Supervisor)

Abstract

Tehran is one of the most polluted megacities in the world, and based on different studies, vehicular sources are responsible for most of the criteria pollutant emissions in this city. The number of vehicles on the streets has been increased drastically leading to growing amount of emission and this trend is continuing. In order to reduce the amount of vehicular emission, it is vital to investigate the factors affecting vehicles emission in this city. This could help to find efficient solutions to improve the situation. Hence, a low-cost methodology to estimate the vehicular emissions is developed. In this...

Projecting emission reductions from prospective mobile sources policies by road link-based modelling

, Article International Journal of Environment and Pollution ; Volume 53, Issue 1-2 , 2013 , Pages 87-106 ; 09574352 (ISSN) Askariyeh, M. H ; Arhami, M ; Sharif University of Technology

2013

Abstract

A methodology was developed to project total vehicular emissions from different emission reduction policies for the light-duty vehicles in the roads network of Tehran, Iran. A road-link-based model was constructed based on a bottom-up approach by coupling COPERT emission functions with the travel demand model of EMME/2. Results showed total emission from the studied network was largely impacted by vehicles' technology and age, speeds in the links, and fuel type. The proper transportation management to reduce the part of passenger cars and improve traffic flow also leads to a significant drop in the emission, e.g., emission decreased by 43% from 20% traffic volume reduction. Results indicated...

A Suitable Strategy in Allocating Financial Resources to Customer in Banking Industry

, M.Sc. Thesis Sharif University of Technology Motedayen, Mohammad Mahdi (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

Nowadays, credit risk is recognized as the most significant factor of bankruptcy in banking industry. Incorrect selection and unsuitable appropriation of financial resources to customers cause this risk. On the other hand, the detection of company operating and financial difficulties is a subject which has been fundamentally discussed in financial ratio analysis. As a result, this study tries to analyze existence and relationship between financial ratios of recipients and their reimbursement ability by evaluation of their conditions in awarding them credit. Furthermore, according to the credit risk context, some of financial ratios are selected and their values are obtained as the input...

Two New Meta-Model Based Artificial Neural Network Algorithms for Constrained Simulation Optimization Problems with Stochastic Constraints

, M.Sc. Thesis Sharif University of Technology Mohammad Nezhad, Ali (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

Following the recent developments in the field of decision making, a considerable number of problems involved with stochastic systems can be thought of whose analysis depends on a set of intricate mathematical relations. In such cases, simulation is one of the most popular tools that can be applied toward analysis of behavior of such stochastic systems. Not only does not the simulation model rely on such intricate mathematical relations, it also enjoys the added advantage of being free of any restricting assumptions which may normally be considered in a stochastic system.To analyze such problem, one may aim at determining the best combination of input variables to optimize the system...

Multi-Objective Simulation Optimization and its Application in Buffer Allocation Problem

, M.Sc. Thesis Sharif University of Technology Marani, Mohammad Reza (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

This work attempts to address the buffer allocation problem in an unreliable, linear production line. We try to determine the optimal sizes of buffers between adjacent work stations in such a way that a measure of costs is minimized and the production rate is simultaneously maximized. We resort to simulation optimization in order to determine the best combination of input parameters that leads to a near optimal performance for the system. To achieve this purpose, we employ a multi-objective genetic algorithm (NSGAII) in the optimization phase along with simulation as the tool for evaluating the objective function. To determine the merits of the proposed method, we compare the performance of...

Developing a Joint Location-Inventory-Transportation Model under Uncertainty

, M.Sc. Thesis Sharif University of Technology Poursaeidi, Mohammad Hossein (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

In this research, an integrated location-inventory-transportation problem with uncertainty in the parameters is analyzed using Robust Optimization techniques. Unknown demand distribution is the underlying assumption, which relates better to the reality. The model’s main purpose is to determine the number and locations of the Distribution Centers (DC) that connect the supplier to the retailers, and then to assign retailers to them. The problem’s mathematical model is developed on the basis of Robust Optimization techniques and the solution space is explored by Tabu Search. The results show that the Tabu Search method achieves optimality in small-scale cases, while providing desirable...

Toroidal Transformer Life Estimation Under Non-Sinusoidal Supply

, M.Sc. Thesis Sharif University of Technology Saket, Mohammad Ali (Author) ; Oraee Mirzamani, Hashem (Supervisor)

Abstract

Due to increase in nonlinear loads in today’s applications, the percent of harmonic content has been increased. Transformers are one of the electrical system components that are subjected to these harmonics. The failure of such equipment is an important consideration. Such failure is because of the hotspot temperature rises over the normal temperature withstanding of internal insulation. The increments of hotspot temperature can decrease the transformer insulation life. Totally, because of the presence of many parameters, precise investigation of loss of life is very difficult. Hence, the only meaning of loss of life in this project is the loss of insulation life under heat stresses....

Design, modeling and analysis of a single phase Brushless Doubly-Fed Generator

, M.Sc. Thesis Sharif University of Technology Haji Mohammad Amini, Hashem (Author) ; Oraee Mirzamani, Hashem (Supervisor)

Abstract

In this thesis, we consider design, modeling, and analysis of a single-phase Brushless Doubly-Fed Machine (BDFM). Generally, this type of machine is called the Brushless Doubly-Fed Induction Machine (BDFIM), that is a new class of induction machines. BDFM is a type of AC machines that requires two alternative power sources. One of the stators windings, called Power Winding, is connected to the network grid and the other one, which is called Control Winding, is connected via a converter, which is in the order of one-third of the nominal power of the machine, to the grid. Like the other types of induction machines, BDFM can also work as a generator or motor. The important criteria of this...

Analysis and Improvement of Dynamic Behavior of Brushless Doubly-Fed Induction Generator in Wind Turbines

, M.Sc. Thesis Sharif University of Technology Tohidi, Sajjad (Author) ; Oraee Mirzamani, Hashem (Supervisor) ; Zolghadri, Mohammad Reza (Supervisor)

Abstract

Recently, the brushless doubly fed induction generator (BDFIG) has been proposed to be used in wind turbines due to variable speed operation with fractionally size power electronic converter and without brushes and slip rings. In this thesis, for the first time, LVRT capability of BDFIG has been assessed regarding the grid codes and several approaches have been suggested for improving it. Firstly, the steady-state performance of the BDFIG in different operating modes has been investigated and required tests have been performed. In addition, a new operating mode named as "double cascade mode" has been introduced. The fault-on performance of BDFIG has also been studied by means of torque-speed...

, M.Sc. Thesis Sharif University of Technology Solaymanian, Miremad (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

In some statistical process control applications, quality of a process or product 1s characterized by a relationship between a response variable and one or more explanatory variables which is referred to as profile by researchers. In some applications such as calibration, this relationship is characterized by a simple linear regression. However, in some situations, more complicated models are needed. It seems that there is a little attention to monitoring of profiles with binary response variables. Furthermore, the extensive applications of binary response variables in real industrial worlds make it necessary to concentrate on this kind of profiles. In this ...

Comparison Between Methods Of Synchronization In A Queue With Finite Customer Population

, M.Sc. Thesis Sharif University of Technology Kazemi, Hesam (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

One technique to reduce variance of output in comparing two or more systems via simulation is random number synchronization. the primary technique for achieving synchronization is to assign an independent seed to each random process and then use the same collection of seeds across all systems . Another way of synchronization in systems with limited customer population is to assign different seed to each customer (transaction) and then use the same collection of seeds across all systems. The main Question to be considered here is which of these methods of synchronization can better reduce variance of output in a queue with finite customer population

Interpretation of the Seven Errors in Bulk Material Sampling with the Aim of Providing a Guideline (Protocol) for Sampling From Liquids - Case of Edible Oil

, M.Sc. Thesis Sharif University of Technology Amini, Ali (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

Sampling is so deep-rooted in our habits that it usually takes place unconsciously. A large number of books and articles have been published in this field. The connection between sampling and quality control is the reason that many industries have focused their attention on sampling; however, only a few numbersare familiar with bulk material sampling related issues. Describing this theory along with its seven errors is the main object of this research. Using this theory, characteristics of the lot of interest was analyzed. Creating necessary conditions for assuring sampling correctness is very critical and if these conditions cannot be provided, implementing some part of the theory issues...

A Novel Metamodel-based Simulation Optimization Algorithm using a Hybrid Sequential Experimental Design

, M.Sc. Thesis Sharif University of Technology Ajdari, Ali (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

In this work, we propose a metamodel-based simulation optimization algorithm using a novel hybrid sequential experimental design. The algorithm starts with a metamodel construction phase in which at each stage, a sequential experimental design is used to select a new sample point from the search space using a hybrid exploration-exploitation search strategy. Based on the available design points at each stage, a metamodel is constructed using Artificial Neural Network (ANN) and Kriging interpolation techniques. The resulting metamodel is then used in the optimization process to evaluate new solutions. We use Imperialist Competitive Algorithm (ICA) which is a powerful population-based...

Using Multivariate Tukey distribution in Multivariare Process Capability Indices

, M.Sc. Thesis Sharif University of Technology Ebrahimi, Samaneh (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

In this thesis we will provide a comprehensive study of process capability indices, and we use multivariate g-and-h Tukey distribution for calculating process capability indices of multivariate non-normal processes. Univariate process capability indices have been used commonly in literature for measuring the capability of a process. However, there are several processes with more than one quality characteristic. When these characteristics are independent, we can use univariate process capability indices, but when the characteristics are dependent we should use multivariate methods for measuring process capability. There have been several studies about multivariate process capability indices,...

Reliability Optimization of Series-Parallel System with Redundancy Allocation and Stochastic Failure Rate

, M.Sc. Thesis Sharif University of Technology Mokhtari, Zahra (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

This thesis presents a method to solve a redundancy allocation problem for the series-parallel system. The modeling formulation deals with the choice of the best redundancy strategy, component and redundancy level for each subsystem in order to maximize the system reliability under system-level constraints. Majority of the solution methods for the general redundancy allocation problems assume that the failure rate of components is determined. However, in practice variable failure rate may be used. The complexity of this problem is known as NP-hard and therefore the optimal solution is not accessible in the normal course of events. It is demonstrated in this thesis that genetic algorithm is...

Nurse Scheduling of an Emergency Department in Order to Decreasing Patients Waiting Time Using Simulation and Genetic Algorithm

, M.Sc. Thesis Sharif University of Technology Fazeli, Sajjad (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

This work attempt to analyze the impact of changes in nurse scheduling on quality of services at emergency department of Emam Khomeini Hospital Complex. In nurse scheduling some constraints such as maximum working hours per week and unacceptable working sequences must be considered. A simulation model is developed to cover the complete flow for the patient through the emergency department. Emergency department of Emam Khomeini is simulated in order to obtain the patient average waiting time for each nurse roster. Then a genetic algorithm is integrated with the simulation model. In each iteration genetic algorithm produces many nurse rosters . For each roster the patient average waiting time...

An Integrated Simulation-DEA Approach to Multi-criteria Ranking of Scenarios for Execution of Operations in a Construction Project

, M.Sc. Thesis Sharif University of Technology Torabi, Mojtaba (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

Before a construction project gets under way an attempt is made to examine different ways and scenarios for its implementation. Through such a process the more appropriate scenarios should be selected based on several criteria that are not necessarily at the same level in terms of importance. The purpose of this study is to examine different scenarios for implementing operations in the pre-construction phase of a project, based on several competing criteria with different importance levels in order to achieve a more efficient execution plan. This paper presents a new framework that integrates discrete event simulation (DES) and data envelopment analysis (DEA) to rank different scenarios for...

Change Point Estimation of Multivariate Multiple Linear Profiles, under Multiple Linear Drifts and Step Changes

, M.Sc. Thesis Sharif University of Technology Karimi, Samira (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

Control charts are the most popular Statistical Process Control tools used to monitor process changes. However, they are not capable of identifying the real time of a process change, which is essential for diagnosing assignable causes of the change. Therefore, a number of methods of change-point estimation have been developed. In the literature, relatively little study has been done on multiple changes. In this research, a new method based on Maximum Likelihood Estimator (MLE) is introduced to identify linear drifts and step changes in multivariate multiple linear profiles. Due to the massive increase in the amount and time of the calculations along with the growth of the number of the...

Robust Optimization for Simulated Systems Using Risk Management and Kriging

, M.Sc. Thesis Sharif University of Technology Mohseni, Ali (Author) ; Mahlooji, Hashem (Supervisor)

Abstract

Many simulation optimization problems are defined in random settings and their inputs have uncertainty. Therefore, in defining an optimal solution for these problems, uncertainties should be taken into account. The primary way of dealing with this , is Robust Optimization which finds solution immune to these changing settings. Aiming at finding a new approach for simulation optimization problems, this study investigates these uncertainties and robust methods. In the optimization problem, the goal and constraints are considered with separate risk measures and a related problem is defined as follows: Minimizing the weighted sum of all risks subject to the problem constraints. To solve the...

Decentralized Active Power Management in PV/Battery Hybrid Source Islanded Microgrids

, Ph.D. Dissertation Sharif University of Technology Karimi, Yaser (Author) ; Oraee, Hashem (Supervisor)

Abstract

Due to environmental concerns and continuous decrease in the price, photovoltaic (PV) generations have been increasing in the recent years. PV units can operate in grid-connected or islanded modes. In grid-connected mode, the PV unit delivers its generated power to the grid; on the other hand, in islanded mode, it supplies the local loads. In this research, a new decentralized power management and load sharing method for a photovoltaic based islanded microgrid consisting of various PV units, battery units and hybrid PV/battery units is proposed. Unlike the previous methods in the literature, there is no need to communication among the units and the proposed method is not limited to the...