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bahrami-nasab--marjan
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Design and Manufacturing of Gradient Cellular Tibial Stem for Total Knee Replacement
, M.Sc. Thesis Sharif University of Technology ; Farahmand, Farzam (Supervisor) ; Bahrami Nasab, Marjan (Co-Supervisor)
Abstract
Loosening of uncemented tibial component is one the most common causes of total knee prosthesis failure which is a result of short-term factors such as instability and incomplete osseointegration as well as long-term factors such as peri-prosthetic stress shielding and bone atrophy. Porous cellular structures for tibial stem have been considered as a solution to this problem. This project is aimed to achieve an optimal gradient porous cellular design of tibial stem that in addition to sufficient mechanical strength, provides a perfect osseointegration and prevents bone resorption by incorporating appropriate porosity size, small micro-motion and favorable stress distribution on bone. A...
Runtime Analysis of Self-adaptive Systems
, Ph.D. Dissertation Sharif University of Technology ; Movaghar, Ali (Supervisor) ; Sirjani, Marjan (Supervisor)
Abstract
Increasing the complexity of software systems, their ubiquitous presence in the human activities, and necessity to preserving the functional and nonfunctional requirements of the systems under an uncertain environment, increase the need for self-adaptive systems. A self-adaptive system changes its structure and behaviors in response to changes in its environment and the system itself. A key research challenge in the self-adaptive community is to guarantee that the system fulfills its requirements. This issue can be addressed by employing formal methods during the design of the software systems. However, the assurance techniques should be used during the execution of the system as well as the...
Theoretical Investigation of Quantum Optical Amplifiers in Quantum Communications
, M.Sc. Thesis Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Bathaee, Marzieh Sadat (Co-Supervisor)
Abstract
Signal transmission of information on noiseless and lossy channels is an important issue in data transmission. Using the amplifier in the transmission channels is a good solution to help send information on longer channels. In classical communication, information can be coded in the amplitude or phase of the field and an amplifier is responsible for amplifying these parameters. If we consider the conditions ideal and ignore electrical noises, Classical mechanics does not impose any restrictions on the amplification of arbitrary classical signals. Instead, in quantum telecommunications the information encoded on the quadrature of the electromagnetic field are mounted on quantum states, such...
Economic complexity and the dynamics of regional competitiveness a systematic review
, Article Competitiveness Review ; Volume 33, Issue 4 , 2023 , Pages 711-744 ; 10595422 (ISSN) ; Shahmoradi, B ; Noori, J ; Turkina, E ; Bahrami, H ; Sharif University of Technology
Emerald Publishing
2023
Abstract
Purpose: This study aims to systematically review the economic complexity literature to advance the knowledge on its contribution to building regional competitiveness. Design/methodology/approach: In this study, we did a systematic review of 111 relevant papers. In this regard, we did a thematic analysis on all the collected papers, which led to a two-level processed approach. In the first level, the contributions of the reviewed articles have been classified into three main streams. In the second level, the findings under each contribution category are analyzed and explained. This approach led to a thematic network demonstrating economic complexity and the dynamics of regional...
Lot sizing and job shop scheduling with compressible process times: A cut and branch approach
, Article Computers and Industrial Engineering ; Volume 85 , 2015 , Pages 196-205 ; 03608352 (ISSN) ; Modarres, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
This paper studies simultaneous lot sizing and scheduling problem in a job shop environment over a finite number of periods. The machines are flexible such that the production manager is able to change their working speeds. Also, the production schedule of the items over machines should be in consistence with technological precedence relationships. The problem is formulated as an integer linear program. Then, a number of valid inequalities are developed based on the problem structures. The proposed valid inequalities are added to the problem formulation in a "cut and branch" manner to accelerate the search process by common solvers. Finally, performance of the valid inequalities is...
Thermal stresses and kinetics of phase transformation on the run-out table after hot strip rolling of low-carbon steels
, Article International Journal of Advanced Manufacturing Technology ; Volume 83, Issue 9-12 , 2016 , Pages 1725-1736 ; 02683768 (ISSN) ; Serajzadeh, S ; Sharif University of Technology
2016
Abstract
A thermo-elastic analysis coupled with a phase change model is employed to evaluate thermal stresses as well as progress of austenite decomposition after hot strip rolling operations. The thermo-mechanical finite element analysis is utilized to assess the distributions of temperature and thermal stresses during cooling while at the same time, a model based on the additivity rule is used to determine the rate of austenite to ferrite decomposition. The proposed model is applicable to multi-pass rolling schedules while the effects of different process parameters including the rolling speed and cooling configuration of the run-out table can be taken into account. In order to verify the...
A Multi-Output high voltage dc power supply with fast regenerative rectifier
, Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 1264-1268 ; 9781538649169 (ISBN) ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
A major problem in a multiple output converter structure is the different power flow via its various outputs. This problem leads to unwanted input DC-link voltage. This paper studies full bridge based DC-DC converters with multiple outputs. The effect of power flow variation is studied and a regenerative converter topology which controls the DC-link voltage by space voltage vector modulation technique is proposed. The proposed converter has a fast response to control the DC-link voltage in an acceptable band. Simulation and experimental results are presented to verify the analytical studies. © 2018 IEEE
Estimation of origin–destination matrices using link counts and partial path data
, Article Transportation ; Volume 47, Issue 6 , 2020 , Pages 2923-2950 ; Shafahi, Y ; Sharif University of Technology
Springer
2020
Abstract
After several decades of work by several talented researchers, estimation of the origin–destination matrix using traffic data has remained very challenging. This paper presents a set of innovative methods for estimation of the origin–destination matrix of large-scale networks, using vehicle counts on links, partial path data obtained from an automated vehicle identification system, and combinations of both data. These innovative methods are used to solve three origin–destination matrix estimation models. The first model is an extension of Spiess’s model which uses vehicle count data while the second model is an extension of Jamali’s model and it uses partial path data. The third model is a...
New half-pixel accuracy motion estimation algorithms for low bitrate video communications
, Article Scientia Iranica ; Volume 15, Issue 6 , 2008 , Pages 507-516 ; 10263098 (ISSN) ; Kasaei, S ; Sharif University of Technology
Sharif University of Technology
2008
Abstract
Fractional-pixel accuracy Motion Estimation (ME) has been shown to result in higher quality reconstructed image sequences in hybrid video coding systems. However, the higher quality is achieved by notably increased Motion Field (MF) bitrate and more complex computations. In this paper, new half-pixel block matching ME algorithms are proposed to improve the rate-distortion characteristics of low bitrate video communications. The proposed methods tend to decrease the required video bandwidth, while improving the motion compensation quality. The key idea is to put a deeper focus on the search origin of the ME process, based on center-bias characteristics of low bitrate video MFs. To employ the...
Half-pixel accuracy block matching motion estimation algorithms for low bitrate video communications
, Article First IEEE and IFIP International Conference in Central Asia on Internet, 2005, Bishkek, 26 September 2005 through 28 September 2005 ; Volume 2005 , 2005 ; 0780391799 (ISBN); 9780780391796 (ISBN) ; Kasaei, S ; Sharif University of Technology
2005
Abstract
Motion estimation at fractional-pixel accuracy results in higher quality video sequences. However, the higher quality is achieved by more computations and increased required motion field bitrates. In this paper, new half-pixel accuracy block matching-based motion estimation algorithms are proposed to improve the rate-distortion characteristics of low-bitrate video communications. The proposed methods especially tend to decrease the required video bandwidth, with no degradation in quality of reconstructed image sequences. The key idea is to put a deeper focus on the origin (zero motion) based on the center-bias characteristics of low bitrate video motion fields. The experimental results show...
An efficient adaptive interpolation scheme for fast mesh-based motion estimation
, Article First IEEE and IFIP International Conference in Central Asia on Internet, 2005, Bishkek, 26 September 2005 through 28 September 2005 ; Volume 2005 , 2005 , Pages 4-7 ; 0780391799 (ISBN); 9780780391796 (ISBN) ; Kasaei, S ; Sharif University of Technology
IEEE Computer Society
2005
Abstract
Motion estimation and compensation is an essential part of existing video coding systems. Compared to the widely used block-matching algorithms (BMA), the mesh-based motion estimation (MME) produces better subjective and objective qualified image sequences in many cases, especially at low bitrates. However, the iterative refinement step of the MME is computationally too expensive. In this paper, we propose a fast MME scheme, which adjusts its interpolation patterns to the motion features of image sequences to achieve higher quality reconstructed results. Experimental results show notable rate-distortion improvement over both the BMA and the conventional non-iterative MME schemes, especially...
Pattern recognition analysis of gas chromatographic and infrared spectroscopic fingerprints of crude oil for source identification
, Article Microchemical Journal ; Volume 153 , 2020 ; Parastar, H ; Sharif University of Technology
Elsevier Inc
2020
Abstract
In this study, a chemometric strategy was developed for analysis of gas chromatographic (GC) and infrared spectroscopic (FT-IR) fingerprints of nine crude oil samples from the main oil wells of Iran to classify them and to find their origins. In this regard, a fractionation method based on saturated, aromatic, resin, and asphaltene (SARA) test was used. Then, these fractions were analyzed by GC-FID and GC–MS. Also, nine crude oil samples were analyzed by FT-IR. The obtained GC fingerprints were aligned using correlation optimized warping (COW) and auto-scaled, and then analyzed using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Evaluation of PCA scores plot...
Vis-NIR hyperspectral imaging coupled with independent component analysis for saffron authentication
, Article Food Chemistry ; Volume 393 , 2022 ; 03088146 (ISSN) ; Parastar, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In the present contribution, visible-near infrared hyperspectral imaging (Vis-NIR-HSI) combined with a novel chemometric approach based on mean-filed independent component analysis (MF-ICA) followed by multivariate classification techniques is proposed for saffron authentication and adulteration detection. First, MF-ICA was used to exploit pure spatial and spectral profiles of the components. Then, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to find patterns of authentic samples based on their distribution maps. Then, detection of five common plant-derived adulterants of saffron including safflower, saffron style, calendula, rubia and turmeric were...
Workspace Analisys of A Multi-Link Cable-Driven Robot With Multiple Connection Of Cable to Multi-Link
, M.Sc. Thesis Sharif University of Technology ; Zohoor, Hassan (Supervisor)
Abstract
As technology develops, the need of instruments which could be used for improving the rate and accuracy of the manufacturing increases. This makes the robots inevitable to use in most industries. Among the robots, cable-driven robots have special characteristics that increase the tendency of using them.Multi-body cable-driven robots are novel type of cable-driven robots that have advantages compared to single-body ones. Capability of use in rehabilitation applications, in which the different parts of human body have to move separately, is one of the advantages of multi-body cable-driven robots.The first aim of this thesis is to extend the tensionable workspace concept for multi-body...
Damage Detection in Plate using Wave Propagation Method
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Structural health monitoring (SHM) has been motivated in aircraft and civil industries over the two last decades. Ultrasonic guided wave propagation technique is one of the best damage detection methods in airplane thin wall structures because of their large distance traveling and low attenuation.
In fact by efficient design of sensors pattern one can effectively pick up the changes that happen in propagated signals due to presence of any kind of structural damage. This could be effectively achieved by numerical simulation techniques like finite element modeling. To obtain a damage detection algorithm based on instantaneous baseline data, here, finite element technique is employed for...
In fact by efficient design of sensors pattern one can effectively pick up the changes that happen in propagated signals due to presence of any kind of structural damage. This could be effectively achieved by numerical simulation techniques like finite element modeling. To obtain a damage detection algorithm based on instantaneous baseline data, here, finite element technique is employed for...
Analysis of Marx Pulsed Power Generator for Improving the Output Voltage Waveform Characteristics
, M.Sc. Thesis Sharif University of Technology ; Kaboli, Shahriyar (Supervisor)
Abstract
In this thesis, marx pulsed power generators are investigated. Due to very large magnitude of its output voltage and very fast rise time, Marx generator is the first choice in lots of pulsed power applications. A significant barrier in the implementation of this generators are the switches with witch the structure is made. The short magnitude nominal voltage and current of the solid state switches lead to use of Spark Gaps in which the determinative parameter of the switch to turn on, is its breakdown voltage. These switches have some limitations in repetition rate and turn off ability. However due to very high range of nominal voltage and currents, they are an appropriate choice for marx...
Providing an Order-Inventory Planning Model using Heuristics or Meta Heuristics Algorithm (case study: khorasan Petrochemical Co.)
, M.Sc. Thesis Sharif University of Technology ; Hajji, Alireza (Supervisor)
Abstract
Planning orders and inventory is one of the most important issues in the planning of petrochemical production. Considering the customization of this industry, orders planning includes a large part of it. Also, in order to reduce the great cost of inventory storage, planning to reduce inventory must be considered. In this regard, we intend to present a model with simultaneous consideration of orders and inventory planning in this research, the ability to decide on acceptance of orders and determine the level of production of products in conditions of uncertainty of demand with random trapezoidal demand in each period can be assumed. This model will practically play a key role in improving...
The Effects of Regulatory on Activities of Transportation Companies
, M.Sc. Thesis Sharif University of Technology ; Samimi, Amir (Supervisor)
Abstract
The growth of road freight transport in recent years, in addition to positive effects, has also left negative externalities. Part of the negative effects such as environmental pollution and damage to infrastructure is exacerbated by the lack of capable transport companies and the low productivity of transportation systems. The government intervenes through regulatory scenarios such as restrictions and tolls to reduce the negative effects on the road transport market. But which scenario is more effective in improving the productivity of the current transportation structure and what will be the consequences? This paper introduces an agent-based micro-simulation to model domestic trucking...
Adjust of Origin-destination Matrices Using Link Counts and Partial Paths Data
, M.Sc. Thesis Sharif University of Technology ; Shafahi, Yousef (Supervisor)
Abstract
This paper presents five origin-destination (OD) flow estimation models using traffic sensors. The first model uses counting sensors data, the second model uses automated vehicle identification (AVI) sensors data and the third, fourth and fifth use combined data of counter and AVI sensors simultaneously. The first to fourth models are bi-level problems that the upper-level minimizes some objective functions where is the distance between estimated flows and observed flows. On the other hand, the lower-level problem finds user equilibrium (UE) flows pattern for estimated origin-destination matrix (ODM). The fifth model is a multi-objective problem, where a bi-level problem is solved for each...
Game theoretic based charging strategy for plug-in hybrid electric vehicles
, Article IEEE Transactions on Smart Grid ; Vol. 5,Issue. 5 , 2014 , pp. 2368-2375 ; ISSN: 19493053 ; Parniani, M ; Sharif University of Technology
2014
Abstract
In the future smart grids, Plug-in Hybrid Electric Vehicles (PHEVs) are seen as an important means of transportation to reduce greenhouse gas emissions. One of the main issues regarding to this sort of vehicles is managing their charging time to prevent high peak loads over time. Deploying advanced metering and automatic chargers can be a practical way not only for the vehicle owners to manage their energy consumption, but also for the utilities to manage the electricity load during the day by shifting the charging loads to the off-peak periods. Additionally, an efficient charging schedule can reduce the users' electricity bill cost. In this paper we propose a new practical demand response...