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nadi-mobarakeh--elham
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Investigation on the Influence of Cooling Rate on Microstructure of CuCr25% Melt-spun Alloy
, M.Sc. Thesis Sharif University of Technology ; Varahram, Nasser (Supervisor) ; Davami, Parviz (Supervisor)
Abstract
The Cu-Cr10% ingots were prepared in induction furnace and these ingots were used to prepare CuCr25% in VAR. The percentages of elements were checked by chemical analysis. The ingots were divided to slices with 20gr mass and these slices were put in quartz tubes. The quartz tubes were assembled in melt spinning machine and the ribbons were quenched onto a rotating copper wheel. Three different wheel speeds, 8, 16, 36 m/s were chosen. The microstructure of the ribbons was examined using a scanning electron microscopy (SEM). The relationship between wheel speed and thickness of the ribbons were compared with mathematical modeling. The disk of ribbons with thickness of 0.5mm and radius of 5mm...
Accelerating Multi-Agent Motion Planning in Complex Environments
, M.Sc. Thesis Sharif University of Technology ; Babazadeh, Maryam (Supervisor)
Abstract
This study investigates the motion planning problem for multiple agents with nonlinear dynamics in environments with static obstacles. Designing safe, smooth, and optimal trajectories for a group of agents operating concurrently in a shared space is a critical challenge in robotics, multi-agent systems, and autonomous navigation. Traditional methods often rely on initial guesses close to the optimal solution or become computationally inefficient at large scales. To address these challenges, this thesis proposes a novel computational framework based on the Alternating Direction Method of Multipliers (ADMM) and the Convex Feasible Set (CFS) algorithm. The framework decomposes the overall...
A study of the reliability of various types of the electric vehicles
, Article 2012 IEEE International Electric Vehicle Conference, IEVC 2012 ; 2012 ; 9781467315623 (ISBN) ; Ghahnavieh, A. R ; Mobarakeh, A. S
2012
Abstract
The reliability Studies are done in order to determine the probability of functioning or availability of different engineering systems. These studies can also provide a basis for comparing different structures of a system and can be used as a tool to improve the system design. Also, reliability is an important consideration in the planning, design and operation of transit system. Since the issue of the reliability of electric vehicles has not been sufficiently and seriously evaluated yet, so in this paper, the reliability of the various types of these kinds of vehicles will be discussed and then the reliability indices of them will be compared with each other and with the conventional cars
Delamination Modeling In Composite Material Under The First Failure Mode
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheyli, Ali (Supervisor)
Abstract
In this research, delamination in compound laminated materials under the I mode loading is studied. In this way, a Double Cantilever Beam is investigated, which is the only experiment to study delamination in standard compound laminated materials. At first, a survey and comprehension of the failure of these materials is performed and the major mode of failure, which is named Delamination Mode is understood. Next, a survey on the possible methods of investigating the delamination phenomena is presented. In the next chapter, possible numerical methods are analysed, and the better performance of Cohesive Zone Model and Virtual Crack Closure Technique is studied. In this research, using the...
Clean-Label Data Poisoning Attack Methods Enhancement in Deep Learning Models
, M.Sc. Thesis Sharif University of Technology ; Rohban, Mohammad Hossein (Supervisor)
Abstract
In recent years, deep learning models have become one of the most widely used models in the field of artificial intelligence by showing high accuracy in various applications, in some of which the accuracy and correctness of the output of the models are very important, and in case of an error, there will be a possibility of chaotic events. Along with the progress of deep learning models, attacks have also been introduced in this field that severely compromises the security of such models and affects the accuracy and correctness of their output. Data poisoning is an attack on deep learning models wherein the attacker manipulates some data examples and adds these poisoned data to the victim's...
Proof Search Analysis in Sequent Calculus for Intuitionistic Logic
, M.Sc. Thesis Sharif University of Technology ; Ardeshir, Mohammad (Supervisor)
Abstract
In this thesis the sequent calculi for intuitionistic logic have been studied and compared with these calculi in classical logic, moreover soundness and completeness theorems for these calculi have been proved. Also an algorithmic method is presented to construct the proof-search with this feature that proof-search terminates and the subformula property preserved. In particular the analysis and comparison of two calculi IG and SIC provided by Tassi and Corsi have been done. Finally, we consider the calculus SJC, stack-based Jankov calculus which is similar to SIC and describes proof-search procedure for weak excluded middle logic. If the proof-search is successful in each calculus SIC or...
Time Series Analysis Using Deep Neural Networks Based on DTW Kernels and its Application in Blood Pressure Estimation Using PPG Signals
, M.Sc. Thesis Sharif University of Technology ; Mohammadzadeh, Narjesolhoda (Supervisor)
Abstract
This work presents a modification of deep neural networks for time series analysis. We used kernel layer(s), as a novel approach, at the beginning of the common deep neural networks. These kernels learn based on dynamic time warping (DTW). In each kernel, DTW is calculated between the kernel value and a part of input time series or a part of last layer output (if the kernel is not in the first layer). DTW also gives an alignment path for the input series. This alignment path is used to defining a loss function with the goal of getting better alignment (lower DTW distance) between the kernel and the other input. Besides getting better accuracy on the examined datasets, the other achievement...
Identifying and Rating Indicators for Measuring Iranian Entrepreneurship Ecosystem based on OECD Framework’s Domains with ANDE Method
, M.Sc. Thesis Sharif University of Technology ; Yavari, Elham (Supervisor) ; Sharif, Hossein (Co-Advisor)
Abstract
“Entrepreneurship ecosystem” is defined as the elements – individuals, organizations or institutions – apart from the individual entrepreneur that are conducive to, or inhibitive of, the choice of a person to become an entrepreneur, or the probabilities of his or her success following launch. Entrepreneurial businesses operate locally or regionally and are therefore subject to local or regional contextual influence. Moreover particularly in larger countries there can exist significant variation in industry structure and economic base across regions, emphasizing the importance of regional focus. Adopting appropriate policies at the regional level need to have a deep and accurate...
A Method for Incremental Learning of Stream Data
, Ph.D. Dissertation Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor)
Abstract
Today, the pace of information generation, fast processing and instant decision-making is increasing. In this regard, one of the main needs in the field of data management and processing is stream data processing. Today's world needs new methods to deal with and analyze these data. Two of the most challenging aspects of data streams are (i) concept drift, i.e. evolution of data stream over time, which requires the ability to make timely decisions against the high speed of receiving new data; (ii) limited memory storage and the impracticality of using memory due to the large amount of data. Clustering is one of the common methods for processing data streams, without having basic knowledge...
A game theoretic framework for DG optimal contract pricing
, Article 2013 4th IEEE/PES Innovative Smart Grid Technologies Europe, ISGT Europe 2013 ; 2013 ; 9781479929849 (ISBN) ; Rajabi-Ghahnavieh, A ; Zahedian, A ; Sharif University of Technology
2013
Abstract
This paper presents a new approach based on multi leader follower game in order to find the optimal contract price of distributed generation in distribution network considering competition among them. The leader problems correspond to the independent DG units who decide to maximize the individual profits, while the follower problem refers to the distribution company (DisCo) which seeks the minimization of the payments incurred in attending the expected demand while satisfying network constraints. Disco can purchase energy either from the transmission network through the substations or from the DG units within its network. The DisCo minimization problem acts as a constraint into the each DG...
A bi-level approach for optimal contract pricing of independent dispatchable DG units in distribution networks
, Article International Transactions on Electrical Energy Systems ; Volume 26, Issue 8 , 2016 , Pages 1685-1704 ; 20507038 (ISSN) ; Rajabi Ghahnavieh, A ; Haghighat, H ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
Distributed generation (DG) units are increasingly installed in the power systems. Distribution companies (DisCo) can opt to purchase the electricity from DG in an energy purchase contract to supply the customer demand and reduce energy loss. This paper proposes a framework for optimal contract pricing of independent dispatchable DG units considering competition among them. While DG units tend to increase their profit from the energy purchase contract, DisCo minimizes the demand supply cost. Multi-leader follower game theory concept is used to analyze the situation in which competing DG units offer the energy price to DisCo and DisCo determines the DG generation. A bi-level approach is used...
Simulation of earthquake records using time-varying ARMA (2,1) model
, Article Probabilistic Engineering Mechanics ; Volume 17, Issue 1 , 2001 , Pages 15-34 ; 02668920 (ISSN) ; Rofooei, F. R ; Ahmadi, G ; Sharif University of Technology
2001
Abstract
In this paper, the time-varying auto regressive moving average (ARMA) process is used as a simple yet efficient method for simulating earthquake ground motions. This model is capable of reproducing the nonstationary amplitude as well as the frequency content of the earthquake ground accelerations. The moving time-window technique is used to estimate the time variation of the model parameters from the actual earthquake records. The method is applied to synthesize the near field earthquakes, Naghan 1977, Tabas 1978, and Manjil 1990 recorded on dense soils in Iran, as well as the Mexico City 1985 earthquake recorded on a site with soft soil. It is shown that the selected ARMA (2,1) model and...
Optimal Contract Pricing of Distributed Generation in Iran
, M.Sc. Thesis Sharif University of Technology ; Rajabi-Ghahnavieh, Abbas (Supervisor)
Abstract
Increase in electricity demands and expansion cost of the power system as well as raising more concerns on environmental issues have led to increasing attraction towards Distributed Generation (DG) application in power systems. DG is generally defined as small generation units, ranging from several KW to several MW, that are installed on the distribution network. In Iran, the energy generated by DG units is purchased by Tavanir or distribution companies through guaranteed fixed-price purchase contract. The contract price imposes substantial effects on the cost and benefit of DG owners as well as those of the distribution company (DisCo). A logical and fair pricing model can provide more...
Winner Strategies in a Simulated Stock Market
, Ph.D. Dissertation Sharif University of Technology ; Zamani, Shiva (Supervisor) ; Yavari, Elham (Supervisor)
Abstract
In this study, we explore the dynamics of the stock market using an agent-based simulation platform. Our approach involves creating a multi-strategy market where each agent considers both fundamental and technical factors when determining their strategy. The agents vary in their approach to these factors and the time interval they use for technical analysis. Our findings indicate that investing heavily in reducing the value–price gap was a successful strategy, even in markets where there were no trading forces to reduce this gap. Furthermore, our results remain consistent across various modifications to the simulation’s structure
Applying Gamification in Corporate Entrepreneurship Culture, Specially Missionary Organizations; Through SafirFilm Case Study
, M.Sc. Thesis Sharif University of Technology ; Yavari, Elham (Supervisor) ; Banki, Sara ($item.subfieldsMap.e)
Abstract
Although existing literature on organizational culture and its change process contains meaningful and rich theories but our studies show that there is no perfect and detailed framework on linking organizational culture change and corporate entrepreneurship culture. In addition to that, Gamification –defined as taking the game design elements into non-game contexts– is a fruitful and academically rich research area. Fortunately an idea proposed recently to explain a method for enhancements in organizational culture in general, and in corporate entrepreneurship culture in particularby Yavari and Jafarian based on using game mechanisms. In their paper "A Gamification-Based Method for Corporate...
Simulation and Evaluation of Dosimetric Parameters of 125I Thermobrachytherapy Source with Ferromagnetic Core
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Abolfazl (Supervisor) ; Sheibani, Shahab (Supervisor) ; Poorbaygi, Hossein (Co-Supervisor) ; Mohagheghpour, Elham (Co-Supervisor)
Abstract
In the method treatment of thermobrachytherapy, the method of this project, simultaneously use of two processes of thermotherapy and brachytherapy is considered, which can be a more effective treatment for the destruction of tumor tissue. In thermotherapy, the temperature of the tissue is artificially raised to a temperature that leads to cell dysfunction resulting in cell death. In brachytherapy, the destruction of defective tissue is done by placing a source in the tissue. In the present project, we supposed to consider both mechanisms simultaneously for treatment at the same time. In this project, radioactive material 125I is used as a source of radiation emission for brachytherapy. In...
Observations on using probabilistic c-means for solving a typical bioinformatics problem
, Article EMS 2008, European Modelling Symposium, 2nd UKSim European Symposium on Computer Modelling and Simulation, Liverpool, 8 September 2008 through 10 September 2008 ; 2008 , Pages 236-239 ; 9780769533254 (ISBN) ; Ghazinezhad, A ; Rasooli Valaghozi, A ; Nadi, A ; Asgarian, E ; Salmani, V ; Najafi Ardabili, A ; Moeinzadeh, M. H ; Sharif University of Technology
2008
Abstract
Recently, there has been great interest in Bio informatics among researches from various disciplines such as computer science, mathematics, statistics and artificial intelligence. Bioinformatics mainly deals with solving biological problems at molecular levels. One of the classic problems of bioinformatics which has gain a lot attention lately is Haplotyping, the goal of which is categorizing SNP-fragments into two clusters and deducing a haplotype for each. Since the problem is proved to be NP-hard, several computational and heuristic methods have addressed the problem seeking feasible answers. In this work it is shown that using PCM to solve Haplotyping problem in DALY dataset yields...
Smart drug delivery: Capping strategies for mesoporous silica nanoparticles
, Article Microporous and Mesoporous Materials ; Volume 299 , 2020 ; Zare, H ; Razavi, S ; Mohammadi, H ; Torab Ahmadi, P ; Yazdani, N ; Bayandori, M ; Rabiee, N ; Izadi Mobarakeh, J ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Systematic delivery of therapeutic agents to specific sites, with a stimulus-responsive drug release profile is currently a rapidly growing area. Mesoporous silica nanoparticles (MSNs) are the useful platforms as drug/gene delivery systems due to their unique properties including the ability to control the pore size, high porosity, and morphology, which can directly affect the mechanism and profile of drug release. The appropriate fabrication strategy can tailor the particle shape and size, leading to enhanced delivery and release mechanisms. The MSN surface can be modified by using either organic or inorganic molecules to induce smart and site-specific drug delivery and release....