A Multi-Objective Optimization Model to Design a Resilient Supply Chain

, M.Sc. Thesis Sharif University of Technology Rostami, Saber (Author) ; Najafi, Mehdi (Supervisor) ; Rafiee, Majid (Supervisor)

Abstract

In recent two decades, occurrence of unexpected disruptions, made supply chains more vulnerable and caused huge damages to them. As a result, in recent researches, the concept of supply chain resilience that concentrates on supply chain vulnerability and disruptions has been focused more. In this thesis, a new framework for resilient suppliers characteristics would be presented that can be used for evaluating resilience level of suppliers and resilient supplier selection. By utilizing scenario-based two-stage stochastic approach, a multi-objective mixed integer nonlinear model is proposed for designing a resilient four echelon supply. In the proposed model, the possibility of partial...

The Effects of Intentional Process Models on Goal Modeling and Process Conformance Checking

, M.Sc. Thesis Sharif University of Technology Farsayyad, Nazi (Author) ; Rafiei, Majid (Supervisor) ; Khedmati, Majid (Supervisor)

Abstract

In recent years, requirement engineering and goal modeling have gained more attention among different organisations. Therefore, different methods have been designed to discover stakeholders’ requirements and translate them into process and organizational goals. Various goal models have been introduced to represent these goals and their relations towards each other. Still, these methods are manual representations of different process scenarios and do not relate to the actual behavior. In 2014, Map Miner Method (MMM) was introduced to discover intentional process models from event logs. MMM uses Hidden Markov Model (HMM) as a means to represent the process as a map model of strategies and...

A Trajectory Recommendation System for Efficient Finding of Passengers

, M.Sc. Thesis Sharif University of Technology Aledavood, Ebrahim (Author) ; Khedmati, Majid (Supervisor) ; Rafiee, Majid (Supervisor)

Abstract

Recommending routes to city taxis in order to improve their performance in finding passengers can reduce traffic, pollution and waiting time for passengers, as well as this, increasing the efficiency of taxis can increase their income. In this study, by analyzing trajectory data obtained from 536 taxis in San Francisco over a period of one month, we generated networks of cells, each of which has time-dependent characteristics such as the probability of finding a passenger, the capacity of each cell, or the amount of demand exists is in the cell and the average speed of passing through that cell. also, the connections between these cells in order to make more use of the experiences of taxi...

Improving Artificial Neural Network Predictive Performance Using Panel Data

, M.Sc. Thesis Sharif University of Technology Alirezaei, Hamid Reza (Author) ; Khedmati, Majid (Supervisor) ; Rafiee, Majid (Supervisor)

Abstract

The purpose of the present study is to develop neural network estimation method for hybrid or panel data which have a combination of two cross-sectional and time series structures and because of the features of both structures, their use in different sciences offers many advantages; and the analytical methods for this data structure are also different from other one-dimensional structures, so different and specific regression models are presented for this data structure. However, in the artificial neural network method, modeling the development for this data structure is neglected, so in the present study, using the concepts of panel regression methods and their application to the...

Undamped oscillations in fractional-order Duffing oscillator

, Article Signal Processing ; February , 2014 , Pages 361–367 ; ISSN: 01651684 Rostami, M ; Haeri, M ; Sharif University of Technology

2014

Abstract

This paper studies unamped oscillations of fractional-order Duffing system. Stability theorems for fractional order systems are used to determine the characteristic polynomial of the system in order to find the parametric ranges for undamped oscillations in this system. We also derive relations for estimating the frequency and the amplitude of the oscillations in this system using a describing function method. Finally numerical simulation results are provided to justify the analysis

Study of limit cycles and stability analysis of fractional arneodo oscillator

, Article Journal of Optimization Theory and Applications ; Volume 156, Issue 1 , 2013 , Pages 68-78 ; 00223239 (ISSN) Rostami, M ; Haeri, M ; Sharif University of Technology

2013

Abstract

This paper deals with the existence and the characteristics of the limit cycles in the fractional-order Arneodo system. The analysis is done using the describing function method. Our focus is on a special case where two limit cycles exist. The parametric range for the case of interest is derived, and the frequency and the amplitude of the oscillation are predicted. Numerical simulation results are presented to further demonstrate the reliability of the analysis

Undamped oscillations in fractional-order Duffing oscillator

, Article Signal Processing ; Volume 107 , February , 2015 , Pages 361-367 ; 01651684 (ISSN) Rostami, M ; Haeri, M ; Sharif University of Technology

Elsevier 2015

Abstract

This paper studies undamped oscillations of fractional-order Duffing system. Stability theorems for fractional order systems are used to determine the characteristic polynomial of the system in order to find the parametric ranges for undamped oscillations in this system. We also derive relations for estimating the frequency and the amplitude of the oscillations in this system using a describing function method. Finally numerical simulation results are provided to justify the analysis

Steel plate shear walls having door openings with different arrangements of stiffeners

, Article Advances in Structural Engineering ; Volume 22, Issue 10 , 2019 , Pages 2222-2235 ; 13694332 (ISSN) Rostami, P ; Mofid, M ; Sharif University of Technology

SAGE Publications Inc 2019

Abstract

As steel plate shear walls are typically used in the building central cores around the elevators and stairs, introduction of an opening as door seems to be inevitable in steel plate shear wall spans. Due to the weakening of the steel plate shear walls’ performance caused by this particular type of opening, the use of stiffeners around the opening is necessary. Nevertheless, introduction of stiffeners around all sides of the opening, which does continue to boundary elements, is very expensive and inefficient. Therefore, the study on the effect of different arrangements of stiffeners on the behavior of steel plate shear walls is significant. In this research, a number of steel plate shear...

A survey on exergy, energy and environmental analysis of sulfur recovery unit in case of five intensified configurations

, Article Chemical Papers ; Volume 73, Issue 6 , 2019 , Pages 1529-1539 ; 03666352 (ISSN) Rostami, A ; Tavan, Y ; Sharif University of Technology

Springer International Publishing 2019

Abstract

In this study, a combination of energy and exergy analysis is applied for the industrial sulfur recovery unit (SRU) in commercial simulation software. The data of energy and exergy are obtained from the simulator and Excel (for physical and chemical exergy), respectively. In doing so, five intensified SRU configurations namely: (1) hot gas bypass (2) acid gas bypass (3) inlet stream preheating (4) acid gas enrichment and (5) oxygen (air) enrichment are compared in terms of energy production, reaction furnace temperature, sulfur recovery and pollutant emission into environment. Then, irreversibility in these five arrangements is compared and all the proposed methods show higher useful exergy...

Topology awareness of overlay P2P networks

, Article Concurrency and Computation: Practice and Experience ; Volume 19, Issue 7 , 2007 , Pages 999-1021 ; 15320626 (ISSN) Rostami, H ; Habibi, J ; Sharif University of Technology

John Wiley and Sons Ltd 2007

Abstract

In overlay networks, the mechanism of a peer randomly joining and leaving a network, causes a topology mismatch between the overlay and the underlying physical topology. This causes a large volume of redundant traffic in the underlying physical network as well as an extra delay in message delivery in the overlay network. Topology mismatch occurs because overlay networks are not aware of their underlying physical networks. In this paper we present a mathematical model for topology awareness of overlay networks (degree of matching between an overlay and its underlying physical network) and the efficiency of message delivery on them. Then we experimentally show that the model is precise in the...

Minimum linear arrangement of Chord graphs

, Article Applied Mathematics and Computation ; Volume 203, Issue 1 , 1 September , 2008 , Pages 358-367 ; 00963003 (ISSN) Rostami, H ; Habibi, J ; Sharif University of Technology

2008

Abstract

The minimum linear arrangement (MINLA) is a NP-hard problem in general. But there are some classes of graphs optimally solvable in polynomial time. In this paper, we solve the minimum linear arrangement problem for a new class of graphs (Chord graphs) in polynomial time. Also, we present a closed formula for the cost of optimal arrangement. Our motivation to solve the problem for this class of graphs is its application in optimization of peer-to-peer overlay networks. © 2008 Elsevier Inc. All rights reserved

A mathematical foundation for topology awareness of P2P overlay networks

, Article 4th International Conference on Grid and Cooperative Computing - GCC 2005, Beijing, 30 November 2005 through 3 December 2005 ; Volume 3795 LNCS , 2005 , Pages 906-918 ; 03029743 (ISSN); 3540305106 (ISBN); 9783540305101 (ISBN) Rostami, H ; Habibi, J ; Sharif University of Technology

2005

Abstract

In peer-to-peer (P2P) overlay networks, the mechanism of a peer randomly joining and leaving a network, causes a topology mismatch between the overlay and the underlying physical topology. This causes a large volume of redundant traffic in the underlying physical network as well as an extra delay in message delivery in the overlay network. Topology mismatch occurs because overlay networks are not aware of their underlying physical networks. In this paper we present a mathematical model for topology awareness of overlay networks (degree of matching between an overlay and its underlying physical network) and the efficiency of message delivery on them. We also after determining the...

Optimal feature selection for SAR image classification using biogeography-based optimization (BBO), artificial bee colony (ABC) and support vector machine (SVM): a combined approach of optimization and machine learning

, Article Computational Geosciences ; Volume 25, Issue 3 , 2021 , Pages 911-930 ; 14200597 (ISSN) Rostami, O ; Kaveh, M ; Sharif University of Technology

Springer Science and Business Media Deutschland GmbH 2021

Abstract

Land cover classification is one of the most important applications of POLSAR images. In this paper, a hybrid biogeography-based optimization support vector machine (HBBOSVM) has been introduced to classify POLSAR images of RADARSAT 2 in band C acquired from San Francisco, USA. The main purpose of this classification is to minimize the number of features and maximize classification accuracy. The proposed method consists of three main steps: preprocessing, feature selection and classification. As preprocessing, radiometric calibration, speckle reduction and feature extraction have been performed. In the proposed HBBO, the combination of onlooker bee of artificial bee colony (ABC) and...

Investigation of Impurities and Structural Defects in Graphene

, M.Sc. Thesis Sharif University of Technology Rostami, Melika (Author) ; Faez, Rahim (Supervisor)

Abstract

In this thesis the effects of impurities and different defects on electrical and magnetic properties of monolayer and bilayer graphene is investigated. Calculations are performed using density function theory. Alloying monolayer graphene with boron and nitrogen the energy gaps of 0.7 and 0.6 eV are obtained, respectively. Moreover, we show that BN is a good candidate for opening the band gap in graphene. Alloying monolayer graphene with BN the energy gap of 1.2 eV is obtained. Another way of opening band gap is to somehow break the symmetry between layers of the bilayer graphene. By alloying one layers of bilayer graphene with B, N or B-N, although the symmetry of layers is broken, each...

On the Characteristics of The Behavior of Multi-story Steel Frames Accompanied by Steel Shear Walls with Openings

, M.Sc. Thesis Sharif University of Technology Rostami, Parisa (Author) ; Mofid, Massoud (Supervisor)

Abstract

As steel shear walls are usually applied in the central cores of buildings (around the elevators and stairs), the use of opening as door is inevitable in steel shear wall spans. On the other hand, because of weakening the performance of steel shear walls due to the presence of these openings, it is necessary to apply stiffeners around it. The use of stiffeners around all sides of opening continued to beams and columns, is very expensive. Therefore, the necessity of studying on the effect of different arrangements of stiffeners on the behavior of steel shear walls is felt. In this research, a number of steel shear walls with different characteristics in terms of plate aspect ratio, location...

Techno-Economical Analysis and Modeling of Carbon Capturing from Flue Gas by Adsorption

, M.Sc. Thesis Sharif University of Technology Rostami, Fatemeh (Author) ; Avami, Akram (Supervisor)

Abstract

Population growth require increasing demand of Energy. The fossil fuels are the main source of energy. However, they are main source of carbon dioxide emissions. Considerable amount of fossil fuels is used in the power plants. Increasing trend of electricity consumption as well as the lack of alternative fuels such as renewables in the short time will increase the consumption of fossil fuels and emissions. The most important greenhouse gas emitted from the power plants is carbon dioxide. That's why the separation of carbon dioxide from the gas stream of power plants is necessary.Separation of the carbon dioxide by adsorption is considered in this project both experimentally and...

Efficient Search in Peer-to-Peer Networks

, Ph.D. Dissertation Sharif University of Technology Rostami, Habib (Author) ; Habibi, Jafar (Supervisor)

Abstract

Peer-to-Peer networks are invented to enable participants (peers) to share their resources and find and use the shared resources of the others. So the main issue is the mechanism of finding granted resources of the other peers. In Peer-to-Peer networks, there is no central server to index shared resources of the peers. So peers should collaborate to provide a fully distributed mechanism for searching resources. Considering the huge size of peer-to-peer systems, it is apparent that efficiency of the search mechanism is very critical. In this thesis, to have efficient seach in Peer-to-Peer networks, we propose two approaches. Then based on these approaches, we propose the third approach to...

Impelementation of Numerical Method For Hydrodynamic Behavior for Salvage of a Sunken Ship

, M.Sc. Thesis Sharif University of Technology Jelodari, Ehsan (Author) ; Abbaspour, Majid (Supervisor)

Abstract

One of the utmost important factors during salvage operation of drowned ships is raising velocity. Uncontrolled raise is a dynamic phenomenon which can lead to the sudden tensions, collapse in airbags or ships. Studing this issue helps the engineers which kinds of problems are more important during salvage operations. This study focus on modeling and analysis of raising movment of the ship with FLOW-3D and ABAQUS software.
In FLOW-3D environment, hydrodynamic analysis of rising movment of drowned ship has been done. We should mention that applied forces and velocities and other parameters from the FLOW-3D output should be passed IMCA Criteria to avoid uncontrollable raise. In ABAQUS...

The Application of Profile Monitoring in Healthcare for Disease Monitoring- case Study

, M.Sc. Thesis Sharif University of Technology Chabok, Sheyda (Author) ; Rafiee, Majid (Supervisor)

Abstract

Profile Monitoring is a new research topics in the field of statistical process control. In many applications of statistical quality control, sometimes quality of a process or product described by a relationship between a response variable and one or more independent variables.The researchers call this relationship profile. The study seeks to demonstrate that monitoring profiles In addition, the industry can be effective in medical field and improves control of the patient's condition by a doctor. Profiles are usually modeled with a linear regression equation, non-linear or polynomial. finally, the results of this study, using actual data, models and methods to predict and control...

Experimental Study on Extracting Clean Energy from Vortex Induced Vibration

, M.Sc. Thesis Sharif University of Technology Mohtat, Pouya (Author) ; Abbaspour, Majid (Supervisor)

Abstract

Two experimental models were designed and tested to extract energy from vortex induced vibrations of a elastically mounted one degree of freedom rigid cylinder in the Reynolds range of 120000 < Re <220000. In the first model the amplitude and frequency of the movement was measured then a second model was designed to be tested in the Emam Hossein marine laboratory. The model was designed in a way that many of its properties like mass ratio, spring constant and damping coefficient were able to be altered. In this study the vortex induced vibration of an elastically mounted cylinder was scrutinized in high Reynolds and very low mass ratios for the first time and an amplitude ratio of 2.49 were...