Sharif Digital Repository / Sharif University of Technology / Search result

Personalized Assortment Optimization Using a Non-Parametric Choice Model

, M.Sc. Thesis Sharif University of Technology Seyed Ghafouri, Mohammad Mahdi (Author) ; Modarres Yazdi, Mohammad (Supervisor)

Abstract

In this study, the problem of assortment optimization considering a non-parametric choice model will be introduced. The present study is generally divided into two main parts. The first part deals with modeling customer behavior using the definition of tree models of customer preference behavior. The second part is related to the main problem solving framework in order to get the best product combination in the product classification basket. This research is related to the online seller who intends to sell a certain number of types of products without inventory limit. Customers entering the system, according to their specifications, are provided with the appropriate product classification...

Effect of Initial Static Shear Stress on Undrained Cyclic Resistance of Well Graded, Medium Dense Gravelly Soils by Cyclic Triaxial Tests

, M.Sc. Thesis Sharif University of Technology Seyed Ghafouri, Mohammad Hosein (Author) ; Haeri, Mohsen (Supervisor)

Abstract

Softening and liquefaction of granular soils due to earthquakes have been a major cause for much destruction in preceding decades. This phenomenon mostly occurs in sandy soils, yet its occurrence has also been reported in gravelly soils in the last three decades. Despite the numerous researches which have investigated the undrained cyclic behavior of gravelly soils during earthquakes, there are still some aspects that need further study.This research investigates the effect of initial static shear stress on undrained cyclic resistance of a well graded, medium dense gravelly soil by conducting a series of cyclic triaxial tests. The 23 performed tests are categorized into 5 groups with...

Utilizing a simulation approach for analysis of patient flow in the emergency department: a case study

, Article 15th Iran International Industrial Engineering Conference, IIIEC 2019, 23 January 2019 through 24 January 2019 ; 2019 , Pages 151-157 ; 9781728117751 (ISBN) Seyed Ghafouri, S. M. M ; Haji, B ; Shakhsi Niaei M ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2019

Abstract

Simulation has been shown to be one of the most powerful tools in many areas of the health-care system, a system which attracted the attention of researchers due to its intricacy. The main goal of this study is to evaluate the patients' flow in an emergency department (ED). Discrete event simulation (DES)has been used as the core of this research so that it offers various ways to reduce the length of stay (LOS)of patients in different segments of ED by assessing various scenarios. In particular, a new approach for verification of the simulated model will be discussed. This study reports on the results that extracted from a case study on patient record data in one of the EDs located in Tehran...

Topics in Measurability and Integrability in Constructive Analysis

, Ph.D. Dissertation Sharif University of Technology Ghafouri, Zahra (Author) ; Ardeshir, Mohammad (Supervisor)

Abstract

In this thesis, we investigate constructive measure theory in two schools of constructivism; intuitionistic mathematics and Bishop’s constructive mathematics.In this regard, first, we examine some classical propositions on measurability in both schools. Then we give a comparison between measurability in the two schools

Study of the Interaction of Non-level Crossing Tunnels, Case Study of Crossing of Tunnels of Line 1 and Line 7 of Tehran Metro

, M.Sc. Thesis Sharif University of Technology Pourjavadi, Sobhan (Author) ; Sadaghiani, Mohammad Hosein (Supervisor)

Abstract

As the crowded cities require public transportation and because of lack of space on the ground, Subway and boring underground tunnels encountered. In this thesis the interaction of boring the line 7 of Tehran metro with the existing station of line 1 of Tehran metro (Molavi station) is studied. By changing the soil specification, The surface settlement is significant so the soil specification is one of the important parameters of the interaction. For comparinf the effect of these parameters, the soil settlement and bending moments is investigated in different parts of station while the lower tunnel is passing beneath it. The 3D Abaqus software is used for modeling this interaction. In...

Study of Loading Orientation Effect on Shear Strength of Rock Mass Discontinuities with Infilling Based on Laboratory Methods

, M.Sc. Thesis Sharif University of Technology Malaksiar, Hosein (Author) ; Sadaghiani, Mohammad Hosein (Supervisor)

Abstract

Recently, Needs for construction of rock structures and underground ones such as tunnels, dam foundations, power plants and caverns built to keep oil, gas and nuclear waste has increased dramatically. In order to design, construct and excavate these underground structures safely and economically, full understanding of rock mass properties, suitable tools and practical techniques of drilling are necessary. Because of existing this discontinuities, including joints and layered rock masses and their effects on mechanical behavior of rock mass, it is necessary for the geomechanical profile, shear strength and failure mechanism of rock mass to be accurately indentified. Shear strength criterions...

The Optimal Catenary Mooring Arrangement for Least Sensitivity to Single Mooring Line Broken in Semi-Submersible Platform

, M.Sc. Thesis Sharif University of Technology Seyed Abbassian, Mohammad Reza (Author) ; Tabeshpour, Mohammad Reza (Supervisor)

Abstract

The discovery of oil and gas resources in deep waters led to the invention of various platforms adapted to these waters. As the search for oil and gas resources is advanced to deep water, it is impossible to use fixed platforms in these depths. Hence, the idea of using floating platforms that can be used in deep waters has been increasingly considered. An option for the exploration and extraction of offshore oil resources is semi-submersible platforms. Under wave, wind, and current forces, a floating structure moves from its initial location. Types of mooring systems are used to maintain the position of the platform. During the life of a platform, mooring lines may be damaged under...

Topological Defects in Confined Nematics by Planar Anchoring

, M.Sc. Thesis Sharif University of Technology Seyed Nejad, Reza (Author) ; Ejtehadi, Mohammad Reza (Supervisor) ; Mozaffari, Mohammad Reza (Supervisor)

Abstract

Confining nematic liquid crystal between two curved boundary conditions while the nematic molecules have a degenerate planar anchoring leads to complex and beautiful textures of molecular disparagement(defect) in the bulk and on the surfaces. Such the liquid crystal shells are made with double-emulsion techniques in microfluidic devices have provided applications for micro-scale colloidal linkers.In this work, we have numerically minimized the elastic energy in one-constant approximation in present of Fournier’s degenerate surface potential with finite element method. The nematic shell is confined between two spherical surfaces that we have studied the final energies and their related...

An adaptive latency mitigation scheme for massively multiuser virtual environments

, Article Journal of Network and Computer Applications ; Volume 32, Issue 5 , September , 2009 , Pages 1049–1063 Hariri, B. (Behnoosh) ; Shirmohammadi, Sh. (Shervin) ; Pakravan, M. R. (Mohammad Reza) ; Alavi, M. R. (Mohammad Hosein) ; Sharif University of Technology

2009

Abstract

As massively multiuser virtual environments (MMVEs) expand in terms of size and user population, they tend toward using P2P architectures as a way to provide scalability without the need for large centralized resources. Distributed hash table (DHT)-based networks have been introduced as a promising option for overlay-based distributed massively multiuser virtual environment applications. However, overlay latency stretch seriously affects MMVE performance where QoS is crucial for real-time user collaboration. This work includes a series of efforts in the alleviation of such undesired latency. Our approach to latency mitigation consists of two phases. First, we propose a position-based ID...

Order Flow Imbalance Effect on Price Movement in Tehran Stock Exchange

, M.Sc. Thesis Sharif University of Technology Seyed Salehi, Mohammad Hossein (Author) ; Barakchian, Mahdi (Supervisor)

Abstract

We investigate order book events impacts on price movement, using the 31 stocks from the Tehran Stock Exchange. We show that in a low-depth market the mid-price change is explained mainly by a linear relationship with our proposed explanatory variable, modified order flow imbalance that represents the depth-adjusted differences of first level orders volumes in different sides of order book. Our results shows that the bid and ask spread has a negative effect on the power of events to move the price

Modeling of Dissolution of Sluge from Evaporation Lagoons of Isfahan's UCF Plant

, M.Sc. Thesis Sharif University of Technology Mireskandari, Seyed Mohammad Mahdi (Author) ; Samadfam, Mohammad (Supervisor) ; Charkhi, Amir (Supervisor) ; Otukesh, Mohammad (Co-Advisor)

Abstract

Uranium conversion process is one of the most important stages in nuclear fuel cycle. The Uranium Conversion Facilities (UFC) of Iran is located in Isfahan. In this plant, the Yellowcake (impure uranium oxide, U3O8) is converted to Uranium hexa-fluoride, UF6. During the process, considerable amounts of uranium-containing liquid waste are generated. This liquid waste was collected in evaporation pools inside the UCF Plant. In the course of time, a thick layer of precipitated salt form in bottom of the pools which are collected and stored in drums inside a building. This solid waste contains uranium at concentration levels much higher than that permitted for land disposal of the waste....

Removal of Fluorine from radioactive solid waste of Esfahan Uranium Conversion Facility

, M.Sc. Thesis Sharif University of Technology Gerami, Vahid (Author) ; Samadfam, Mohammad (Supervisor) ; Khanchi, Alireza (Supervisor) ; Gasemi, Hosein (Co-Advisor)

Abstract

Uranium is the most important element in the nuclear fuel cycle. Recovery of uranium from waste produced at every stage of the fuel cycle is not only economically important, but also environmentally important. In the production phase of uranium hexafluoride, certain amount of solid waste is produced in the bottom of the fluorination reactor. In order to extract the uranium from this waste, we have to eliminate the fluorine contained in the waste. This is because the fluorine forms strong complex with uranyl ions during the extraction process, and prevents from efficient extraction of uranium. In the current thesis؛ first, we examined the characteristics of the waste ...

Study of Effective Parameters on Helium Liquefaction Cycle using Exergy Analysis

, M.Sc. Thesis Sharif University of Technology Eslami, Mahdi (Author) ; Afshin, Hosein (Supervisor)

Abstract

Liquefaction of gases is one of the applications of cryogenic science. Among the gases, Helium has the lowest boiling point, which at a pressure of 1atm is approximately 4.2K. Liquid helium can be used to cool superconductors in transportation equipment, military radars, and medical imaging equipment. For helium liquefaction, various cycles are used; these cycles have different parameters in their structure such as of input mass fraction to expanders, heat exchanger effectiveness, expander arrangement and ... which their analysis for improving the performance of the cycle is important. In this research, the aim is to study 2, 3 and 4 expander cycle with various parameters and structure. For...

Study of Viscoelastic Properties of Biopolymer Solutions

, M.Sc. Thesis Sharif University of Technology Shahmoradi, Mohammad Reza (Author) ; Seyed Reihani, Nader (Supervisor)

Abstract

Properties of viscoelastic of biopolymers have important role in cells structure; for example: cell motility depends on viscoelastic propertie of Actin polymer. therefore according to its importance ,in this thesis we intend to examine the viscoelastic modulus using Optical tweezers and dissipation theorem.this method is benefits than methods of active microrheology. for example this method can be used for low concentrations; because in the low concentrations, the exerting force will cause changing in the state of matter that here we investigate destructive force effect. we investigate viscoelastic of water for method accuracy then obtain viscoelastic of Kelcogel

Application of artificial neural network for prediction of risk of multiple sclerosis based on single nucleotide polymorphism genotypes

, Article Journal of Molecular Neuroscience ; Volume 70, Issue 7 , 2020 , Pages 1081-1087 Ghafouri-Fard, S ; Taheri, M ; Omrani, M. D ; Daaee, A ; Mohammad Rahimi, H ; Sharif University of Technology

Humana Press Inc 2020

Abstract

The artificial neural network (ANN) is a sort of machine learning method which has been used in determination of risk of human disorders. In the current investigation, we have created an ANN and trained it based on the genetic data of 401 multiple sclerosis (MS) patients and 390 healthy subjects. Single nucleotide polymorphisms (SNPs) within ANRIL (rs1333045, rs1333048, rs4977574 and rs10757278), EVI5 (rs6680578, rs10735781 and rs11810217), ACE (rs4359 and rs1799752), MALAT1 (rs619586 and rs3200401), GAS5 (rs2067079 and rs6790), H19 (rs2839698 and rs217727), NINJ2 (rs11833579 and rs3809263), GRM7 (rs6782011 and rs779867), VLA4 (rs1143676), CBLB (rs12487066) and VEGFA (rs3025039 and...

An Investigation of a Fuzzy Transformation of Variables on the Robustness of Choice Models

, M.Sc. Thesis Sharif University of Technology Sherafatipour, Saeid (Author) ; Pourzahedi, Hosein (Supervisor)

Abstract

Estimation of demand, for example, for transportation is an important issue for the planning and programming of various systems. Thus, enhancing the predictability power of such models is of high value. Demand stems from choices of individuals, and choice is subject to uncertainty and fuzziness. Uncertainty comes from many factors including incomplete information of decision-maker, and fuzziness comes from many other factors including personal perception regarding the value of the variables affecting choice. This study tries to introduce a new approach in building choice models, in which variables are transformed into another variable by the help of a global wisdom. This wisdom shows the...

Text to Phoneme Transcription Capable to Detect Ezafe and Homographs for Persian Speech Synthesis

, M.Sc. Thesis Sharif University of Technology Oskouipour, Navid (Author) ; Sameti, Hosein (Supervisor)

Abstract

In Persian language, there are some special uncertainties and complexities regarding the extraction of phonemes due to its flexible structure. In this work, we try to solve two problems caused by this issue, homographs disambiguation and Ezafe recognition in Persian text to speech systems.
In this work, two methods are presented for solving the two problems. The first one is a pattern recognition method based on Aho-Corasick algorithm that has the best performance according to the execution time. The second method is a hidden Markov model tagger based on Viterbi algorithm that uses bigram and trigram statistics. These methods are run on 10 million word corpus and the results are compared...

Predictive and Nonlinear Control of Aircraft in Presence of Microburst Wind Shear

, M.Sc. Thesis Sharif University of Technology Jafari, Navid (Author) ; Pourtakdoust, Hosein (Supervisor)

Abstract

Airplanes usually experience minor position change and height loss during cruise flight, but under normal circumstances the aircraft total energy is adequately acceptable to maintain the trajectory and the desired performance without severe oscillations. On the other hand, if the airplane encounters a wind-shear or microburst during take-off or landing phases, it would be a dangerous situation, as the aircraft kinetic and potential energy levels are not as high.
In this research, a model predictive controller is designed and investigated to allow a transport category aircraft to either escape or penetrate the microburst. In this regard, initially a DMC controller is designed for 6-DoF...

Know-how-first anti-intellectualism: Williamson against Williamson

, Article Synthese ; Volume 200, Issue 4 , 2022 ; 00397857 (ISSN) Hosein, M ; Khalaj, M. A ; Sharif University of Technology

Springer Science and Business Media B.V 2022

Abstract

Inspired by Williamson’s knowledge-first epistemology, I propose a position on practical knowledge that can be called the ‘know-how-first view’; yet whereas Williamson is one of the pioneers of the new intellectualism about know-how, I employ the know-how-first view to argue against intellectualism and instead develop a know-how-first version of anti-intellectualism. Williamson argues that propositional knowledge is a sui generis unanalyzable mental state that comes first in the epistemic realm; in parallel, I propose that know-how is a sui generis unanalyzable power that comes first in the practical realm. To motivate this suggestion, I put forward two arguments: (1) drawing on...

Comparison models evaluating countermeasures at Highway-Railway Grade Crossings

, Article ICTIS 2013: Improving Multimodal Transportation Systems - Information, Safety, and Integration - Proceedings of the 2nd International Conference on Transportation Information and Safety ; 2013 , Pages 1934-1945 ; 9780784413036 (ISBN) Ghafouri, R ; Bagheri, M ; Sharif University of Technology

2013

Abstract

This paper reviews the literature concerning the effectiveness of countermeasures at Highway-Railway Grade Crossings (HRGC). HRGC are considered as the hotspots in railway transportation systems. So far, there has been significant discussion about different types of countermeasure to mitigate the risk of accidents at HRGC. Different approaches have been developed about the effectiveness of the countermeasures including the Before-After and Cross-Sectional. This paper compares all different studies to evaluate the effectiveness of countermeasure in reduction of accident frequency and severity