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eshraghi--mohammad-hossein
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The Impact of Information Sharing on Performance of an M/M/1 Queueing System
, M.Sc. Thesis Sharif University of Technology ; Abouee-Mehrizi, Hossein (Supervisor)
Abstract
Social media can be helpful to people in vast areas, especially in queuing systems, in the real world there is remarkably unknown information like service time, average waiting time or average queue length to customers, thus people are likely to share their experiences to posterior customers who want to use the same service. This research examines the impact of user-generated reviews, on the performances of a Markovian queuing system, we assumed that customers are not aware of the service rate, therefore they will assist next customers by writing reviews about their service time they had experienced. We intend to examine the impact of information on queueing performance such as system...
Evaluating the Effectiveness of Supportive Innovation Policies on New Technology-Based Firms’ Success in Reaching the Growth Stage
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Iman (Supervisor) ; Vesal, Mohammad (Supervisor)
Abstract
New technology-based firms (NTBFs) are the driving force behind creating innovation and technology in countries and can play a crucial role in job creation and economic growth. These companies also facilitate technology transfer and strengthen the absorptive capacity of national innovation systems. Therefore, given the externalities of these companies, as well as their significant role in promoting innovation, governments around the world implement policies to support these firms. In Iran, the Vice President for Science and Technology has implemented policies to support NTBFs since 2013. Recently, a few studies have been carried out to evaluate these policies. However, the number of these...
A new approach for solving resource constrained project scheduling problems using differential evolution algorithm
, Article International Journal of Industrial Engineering Computations ; Volume 7, Issue 2 , 2016 , Pages 205-216 ; 19232926 (ISSN) ; Sharif University of Technology
Growing Science
2016
Abstract
One subcategory of project scheduling is the resource constrained project scheduling problem (RCPSP). The present study proposes a differential evolution algorithm for solving the RCPSP making a small change in the method to comply with the model. The RCPSP is intended to program a group of activities of minimal duration while considering precedence and resource constraints. The present study introduces a differential evolution algorithm and local search was added to improve the performance of the algorithm. The problems were then solved to evaluate the performance of the algorithm and the results are compared with genetic algorithm. Computational results confirm that the differential...
Reshaping energy policy for sustainable development: Curbing Iran’s carbon emission monster via renewable energies
, Article Energy Sources, Part B: Economics, Planning and Policy ; Volume 11, Issue 9 , 2016 , Pages 830-840 ; 15567249 (ISSN) ; Maleki, A ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
This paper formulates flow of energy from primary resources and import routes to different socio-economic sectors by making use of Long-Range Energy Alternatives Planning (LEAP) model. It presents a baseline of how Iran’s future production and consumption patterns evolve. It also seeks plausible scenario for renewable energies utilization and evaluates its mitigation potential and economic aspects. Model results indicate that exploitation of a "not-too-strict" package of renewable sources featuring 10 GW of wind and 19 GW of hydro by the end of 2035 will lead to CO2 emissions to be reduced up to an amount of 190.7 million tons in the study period. By accounting for the opportunity costs...
Development of an Analytical Framework for Evaluation of Climate Change Mitigation Policies on Iran’s Energy Security
, M.Sc. Thesis Sharif University of Technology ; Maleki, Abbas (Supervisor)
Abstract
Climate change and energy security are key drivers for future energy policy. While energy security has been a pillar of energy policy for about a century, concern about climate change is more recent and is bound to radically change the landscape of energy policy. Policy makers are now under increasing pressure to address these twin challenges: to develop cost-effective policies that will both ensure the security of our energy system and reduce greenhouse gas emissions.
Main Effort in this Project is to construct an integrated model of Iran’s energy system to serve as a policy analysis tool, by which policymakers are able to identify the future effects of a wide range of policies in...
Main Effort in this Project is to construct an integrated model of Iran’s energy system to serve as a policy analysis tool, by which policymakers are able to identify the future effects of a wide range of policies in...
A Study on the Effect of Foundation Uplift on Response of Soil-Structure Systems Using Endurance Time Method
, M.Sc. Thesis Sharif University of Technology ; Ghannad, Mohammad Ali (Supervisor) ; Esmaeil Pourestekanchi, Homayun (Supervisor)
Abstract
In recent decades, the soil-structure effect has been considered in seismic studies. Most of these researches are based on the premise that the foundation is bonded to the ground. However, several examples of structures that experienced uplift have been reported. Uplift affects the soil-structure contribution and nonlinear behavior of the structure. It seems that a parametric study should be done for the simultaneous effects of the soil-structure interaction, foundation uplift and inelastic behavior of the superstructure. Although the most accurate methods to estimate the behavior of structures is the nonlinear time history analysis, this analysis is very time consuming. The endurance time...
Numerical Modeling of Non-Cemented and Cemented Ballast Aggregates under Triaxial Test with a Flexible Membrane Using Discrete Element Method (DEM)
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
This research deals with numerical simulation of triaxial test to determine behavior of non-cemented and cemented ballast aggregates used in base and subbase of roads and railroads. Ballast aggregates, thanks to their high strength and durability, are widely used in various fields including dam, river, road construction, and railway. One of the most widespread uses of this material is in the road body, and according to the recommendation of the British Highway Center, the materials used in the road body are well-graded gravel with the maximum size of 20 mm. Cement is also used as a corrective material to enhance the performance of road bodies. Therefore, knowing the characteristics of these...
Combustible organic materials : determination and prediction of combustion properties
, Book
De Gruyter
2018
The Study of Eliminating Gender Gap in Iran Labor Market on Participation Rate of Married Urban Women
, M.Sc. Thesis Sharif University of Technology ; Rahmati, Mohammad Hossein (Supervisor) ; Joshaghani, Hossein (Supervisor)
Abstract
The low female labor force participation rate in the Iranian labor market relative to the global average and even to countries that do not differ significantly from the socio-economic characteristics of our country is one of the important questions of the Iranian labor market. In this study, we seek to answer the question of whether the economic participation rate of married women will increase if the gender gaps in wages, job findings and job losses among women and men are eliminated in the Iranian labor market. To answer this question using household expenditure and income data and labor force data, we show that between the two categories of occupations, in terms of the share of women's...
Crack Detection in a Rotor using Traditional Mode Shape Based Modal Analysis Methods and Experimental Evaluation
, M.Sc. Thesis Sharif University of Technology ; Mohammad Navazi, Hossein (Supervisor)
Abstract
Fatigue crack growth can have harmful effects on the reliability rotary machine. While an early warning to crack, can be used to extend the life of these expensive machines and increase reliability.Structural Vibration Condition Monitoring as a primary fault detection method, achieved to a lot amazing result and for this reason studies vibration behavior of cracked rotational shaft is a big issue for engineers of dynamic machine.In this research, first check the fault detection methods based on structural vibration condition monitoring, mode shape methods were extracted. Then by modeling rotational shaft in computer and creation of crack on it, fault detection quality of these methods have...
Investigating and Analyzing the Optimal Method for Construction of Keshavarz Metro Station on Line Three of Esfahan Urban Railway
, M.Sc. Thesis Sharif University of Technology ; Sadaghiani, Mohammad Hossein (Supervisor)
Abstract
It is important to provide an appropriate and economically method with technical and engineering considerations to stabilize excavated underground spaces. The necessity of this, especially for the construction of underground metro stations located in the cities which faces many problems, is more evident. In this research, it has been tried to introduce an optimal method according to the type of area for the construction of the underground station. In order to obtain stress and strain condition in structural elements and surface deformations due to different stages of excavating, numerical modeling in FLAC3D has been used. By examining the parameters that affect the sustainability of this...
The Effect of Increasing The Value of Natural Gas Production on Property Value, Wages, Unemployment Rate and Birth Rate in The United States of America (2000-2011)
, M.Sc. Thesis Sharif University of Technology ; Rahmati, Mohammad Hossein (Supervisor)
Abstract
In the present study, the effects of increasing the value of shale gas production, either due to increased production or price increases, have been studied on economic variables such as employment, wage, property value and the number of births. In this regard, the data for each of these variables was used at the county level in the United States of America between 2000 and 2011. In order to estimate the desired effects, counties are divided into two types of boom and non-boom counties. The findings indicate that increasing natural gas production will lead to more employment and wage growth in boom counties than non-boom counties. Also, during the period of increasing production, the value of...
Inflationary Permanent and Long-Term Positive Interest Rate Shocks
, M.Sc. Thesis Sharif University of Technology ; Rahmati, Mohammad Hossein (Supervisor)
Abstract
Co-movement between inflation and nominal interest in response to an interest rate shock, dubbed neo-fisherianism, has been the subject of contentious debate since the advent of non-inflationary ZLB environment. We design an economic model rich with banking features to understand the economic responses to permanent and long-term interest rate shocks. We find that responses to a permanent positive interest rate shock depend on the monetary authorities’ speculation of the new long-term inflation rate, with the most probable outcome being a permanent increase in inflation. Responses to a long-term positive interest rate shock depict an increase and then decrease in inflation. We also discover...
Learning Interpretable Representation of Drugs based on Microscopy Images
, M.Sc. Thesis Sharif University of Technology ; Rohban, Mohammad Hossein (Supervisor)
Abstract
In this study, we aim to learn representations from microscopic cell images that effectively capture the features of drugs affecting the cells, allowing us to identify effective drugs for treating a disease. We employ two parallel learning paths using predictive and generative models. Specifically, we have achieved a predictive model on the RxRx19a dataset that, unlike previous models, is interpretable, optimized, and robust to dras- tic changes in drug properties. Additionally, we have developed the first generative model on this dataset, which not only generates high-quality images but also discovers a meaningful latent space. This latent space divides the representation into relevant...
A new model for robust facility layout problem [electronic resource]
, Article Information Sciences, Elsevier ; Volume 278, 10 September 2014, Pages 498–509 ; Eshghi, Kourosh ; Salmani, Mohammad Hassan ; Sharif University of Technology
Abstract
The Facility Layout Problem (FLP) is the problem of locating each department in a long plant floor without any overlap between departments in order to minimize the material handling cost. The main purpose of this study is to show the effectiveness of a robust approach to solve FLP. In this study, it is assumed that the departments’ length and width are not predetermined. For modeling this kind of uncertainty, the size of each department is considered as a bounded variable and two new parameters are also introduced to implement a robust approach. Moreover, a new adaptive algorithm is designed to determine the robust layout with respect to the decision makers’ requirements. Furthermore, the...
Interaction of Parallel Tunnels; Case Study: Interaction of Towhid Tunnel and Tehran Metro line 7 Tunnel
, M.Sc. Thesis Sharif University of Technology ; Sadaghiani, Mohammad Hossein (Supervisor)
Abstract
Influence of excavating the Tehran metro line 7 tunnel on surface settlement, stresses and deformations induced in Towhid tunnel is investigated using numerical modeling. Construction of Metro tunnel as the new one must be carried out without imposing any damage to the Towhid tunnel as the existing tunnel. Towhid tunnel is a set of twin tunnels along the Chamran highway in Tehran. The tunnels were constructed using sequential excavation method and lined with cast in place reinforced concrete; on the other side metro line 7 is being constructed using 2 EPB tunnel boring machines and lined with reinforced concrete segments. This research consists of the study of the effects of pillar width,...
Pore-Scale Experimental Study of Foam/Nano-Foam Flooding to Heavy oil in Heterogeneous Five-Spot System: Stability Analysis and Displacement Mechanisms
,
M.Sc. Thesis
Sharif University of Technology
;
Ghazanfari, Mohammad Hossein
(Supervisor)
Abstract
Foam injection for enhanced oil recovery is concerned by petroleum engineers because it decreases adverse effects of fingering and gravity segregation caused by the injected fluid .Obviously foam stability is an important factor in the efficiency of this process. So investigating it is an imperative. One of the ways that less studied and can improve foam stability is using of nanoparticles. In this project effect of nanoparticles on foam stability and displacement mechanism during foam flooding has been discussed.
Study consisted of two sets of experiments. In the first part, the static foam stability in the presence of silica nanoparticles has been investigated. Also influence of...
Study consisted of two sets of experiments. In the first part, the static foam stability in the presence of silica nanoparticles has been investigated. Also influence of...
Modeling and Simulation of Miscible Flow through Fractured Porous Media Using Random Walk Method
, M.Sc. Thesis Sharif University of Technology ; Ghazanfari, Mohammad Hossein (Supervisor)
Abstract
Miscible displacement in fluid flowing through a porous medium plays an important role in many environmental and industrial applications; for instance, miscible displacements in enhanced oil recovery processes and pollutant spreading in groundwater. A large number of numerical approaches have been developed to solve the advection-dispersion equation that describes the behavior of miscible displacement in porous media. Most of these numerical models suffer from numerical dispersion. Random walk seems to be an effective method to overcome this problem especially in heterogeneous media. Here, a random walk model was developed and used for simulating miscible displacement in heterogeneous porous...
Spherical Graphite Cast iron Production from Sponge Iron
, M.Sc. Thesis Sharif University of Technology ; Ashuri, Hossein (Supervisor)
Abstract
Due to the increasing spread of metal industries and the need for raw material as feed for electric furnaces in order to produce cast iron and steel, as well as scrap deficiency and rising prices, the use of sponge iron as a substitute for scrap was considered in this project Therefore, in order to achieve the chemical analysis of the sorel ingot that is special for spherical graphite cast iron production with low manganese and chromium content, the direct reduction process was carried out using tunnel kiln method on low-manganese iron ore concentrate.After the investigation on direct reduction parameters including the saggers and coal grading,the produced sponge iron has melted in...
Non-stationary Vibration of a Rotor with Foil Gas Bearings Passing Through Critical Speeds
, M.Sc. Thesis Sharif University of Technology ; Mohammad Navazi, Hossein (Supervisor)
Abstract
The use of air bearings was began the last decade. Oil-free air bearing technology is implemented in rotating machines such as turbines, Micro gas turbines and turbocharged, this technology has improved the efficiency of rotating systems. In rotating machines, at high speeds, passing through the critical speed happens. As a result, the natural frequency of the system is crossing the critical speed, which causes system instability and lack of system amplitude control. Instability causes damage to the system. The aim of this thesis is to investigate the nonstationary vibrations of a flexible rotor with air bearings in the passing critical speeds. Behavior of air bearings is also considered to...