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asadi-ghajarlu--ziya
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Simulation and Optimal Design of Thermal Management Systems for EV Battery Packs
, M.Sc. Thesis Sharif University of Technology ; Moeini Aghtaee, Moein (Supervisor)
Abstract
With the growing demand for electric vehicles (EVs) as a sustainable solution to reduce emissions, thermal management of lithium-ion batteries has become a critical challenge. These batteries operate optimally within a temperature range of 20 to 40°C, and deviations from this range can lead to reduced lifespan, increased internal resistance, and even thermal runaway risks. This study explores cooling systems based on cold plates and heat pipes, proposing an innovative design inspired by the vascular structure of tree leaves. The modeling introduces a nature-inspired pattern for the thermal plate design, aiming not only to lower the average temperature of battery cells but also to achieve...
Probabilistic modeling framework for flood risk assessment: A case study of Poldokhtar city
, Article Journal of Hydrology: Regional Studies ; Volume 47 , 2023 ; 22145818 (ISSN) ; Safaie, A ; Sharif University of Technology
Elsevier B.V
2023
Abstract
Study region: Poldokhtar City is located on the bank of the Kashkan river in Iran. Study focus: This study presents a probabilistic modeling framework for flood risk assessment using Monte Carlo simulations. We developed a Machine Learning (ML)-based flood depth prediction model for Poldokhtar city using the Least Squares Support Vector Machine. HEC-RAS was utilized for 2D flood modeling, and its performance was evaluated by comparing simulated and remote sensing-derived flood extent maps. The simulated results were used to develop a surrogate ML-based model that predicts flood depth maps. Finally, we used this model to estimate the flood risk of Poldokhtar city as a combination of hazard,...
The effects of balance board on the balance parameters in five children with spastic cerebral palsy
, Article Journal of Pediatric Rehabilitation Medicine ; Volume 16, Issue 1 , 2023 , Pages 149-156 ; 18745393 (ISSN) ; Asheghan, M ; Ziya, M ; Holisaz, M. T ; Sharif University of Technology
IOS Press BV
2023
Abstract
PURPOSE: This study evaluated the effects of an instrumented balance board on the balance parameters in children with spastic cerebral palsy by carrying out a pilot single-group pre-post clinical trial. METHODS: Five children aged 5 to 15 years with spastic diplegia and a Gross Motor Function Classification System level of I or II were included. All participants attended 20 sessions with an instrumented balance board, 45 minutes per session, 3 times a week for 7 weeks. The main outcome measures included the center of pressure excursion, velocity, and overshoot during quiet standing with open and closed eyes. The assessments were performed in the mediolateral and anteroposterior directions at...
Probabilistic Assessment of Flood Risk Using Data-Driven Flood Depth Modeling: A Case Study of Poldokhtar City
, M.Sc. Thesis Sharif University of Technology ; Safaie Nematollahi, Ammar (Supervisor)
Abstract
The present study aims to evaluate the flood risk of Poldokhtar city probabilistically using Monte Carlo Simulations (MCS). Two-dimensional (2D) models, which are highly accurate, have been used widely for flood modeling. However, they are not suitable for applications such as MCSs that need to be repeated many times or real-time flood forecasting applications, which require that flood inundation maps quickly be produced. In the current study, we developed a data-driven surrogate model based on the Least Squares Support Vector Machine (LS-SVM), a supervised machine learning method, to predict flood depth in order to simulate similar results to 2D hydraulic modeling. HEC-RAS was used for 2D...
A uniquely 3-list colorable, planar and k4-free graph
, Article Journal of Combinatorial Mathematics and Combinatorial Computing ; Volume 72 , 2010 , Pages 115-120 ; 08353026 (ISSN) ; Sharif University of Technology
2010
Abstract
Let G be a graph with v vertices. If there exists a collection of list of colors S1, S1,..., Sv on its vertices, each of size k, such that there exists a unique proper coloring for G from this list of colors, then G is called a uniquely k-list colorable graph. In this note we present a uniquely 3-list colorable, planar and K4-free Graph. It is a counterexample for a conjecture by Ch. Eslahchi, M. Ghebleh and H. Hajiabolhassan [3]
Evaluating Reliability of SSDs Against Power Outage
, M.Sc. Thesis Sharif University of Technology ; Asadi, Hossein (Supervisor)
Abstract
Solid-State Drives (SSDs) provide high performance, low power consumption, and hence are widely used in the I/O cache of enterprise storage systems and high performance servers. Although employing high performance SSDs in the I/O cache of storage systems significantly improves system performance, it comes with significant reliability threats for write operations upon power failures. In order to provide high level of reliability, storage architectures employ SSDs in I/O cache with RAID-1 configuration, however, such configuration only partially mitigates the reliability issues of the SSDs. In this thesis, we analyze the reliability of SSD-based I/O caches against power outage and high...
Multi directional forging of 2024 Al alloy after different heat treatments: Microstructural and mechanical behavior
, Article Transactions of the Indian Institute of Metals ; 2016 , Pages 1-13 ; 09722815 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
Springer India
2016
Abstract
Improvement of mechanical properties and microstructure of 2024 aluminum alloy by performing a severe plastic deformation method, called multidirectional forging (MDF), and heat treatment was the aim of this research. In this work, the effects of different heat treatments such as annealing, solid solution, peak ageing and over ageing before MDF on mechanical properties and microstructure of the alloy were studied. Microstructure evolution during severe plastic deformation was considerably affected by the precipitates and non-shearable particles. On the other hand, the severe plastic deformation had different effects on precipitates in the microstructure. Fragmentation, scattering and...
Utilizing mixed methods research in analyzing Iranian researchers' informarion search behaviour in the web and presenting the current pattern
, Article Iranian Journal of Information Processing Management ; Volume 31, Issue 1 , 2015 , Pages 27-57 ; 22518223 (ISSN) ; Hariri, N ; Sharif University of Technology
Iranian Research Institute for Scientific Information and Documentation
2015
Abstract
Using mixed method research the current study has analyzed Iranian researchers' information searching behavior on the Web. Based on extracted concepts, the model of their information searching behavior was revealed. Forty-four participants, including academic staff from universities and research centers were recruited for this study selected by purposive sampling. Data were gathered from questionnaires including ten questions and semi-structured interview. Each participant's memos were analyzed using grounded theory methods adapted from Strauss & Corbin (1998). Results showed that the main objectives of subjects were doing a research, writing a paper, studying, doing assignments, downloading...
The relationship between the research activity of Iranian medical universities and their web impact factor
, Article Electronic Library ; Volume 27, Issue 6 , 2009 , Pages 1026-1043 ; 02640473 (ISSN) ; Shekofteh, M ; Sharif University of Technology
2009
Abstract
Purpose - The aim of this paper is to look at the relationship between research in Iranian medical universities, together with their Web Impact Factor (WIF). Design/methodology/approach - The Altavista search engine was chosen because of its advanced search facilities for counting links and having a wider scope of academic web sites than other search engines. It was searched for determining the number of pages, in-links and self-links of 42 web sites of Iranian medical universities. The Web Impact Factor (WIF) was calculated by two formulas and the relationship between the two grades of universities (WIF and ISI) was calculated by using the Spearman's correlation coefficient. Findings -...
Multi directional forging of 2024 Al alloy after different heat treatments: microstructural and mechanical behavior
, Article Transactions of the Indian Institute of Metals ; Volume 70, Issue 7 , 2017 , Pages 1707-1719 ; 09722815 (ISSN) ; Kazeminezhad, M ; Sharif University of Technology
2017
Abstract
Improvement of mechanical properties and microstructure of 2024 aluminum alloy by performing a severe plastic deformation method, called multidirectional forging (MDF), and heat treatment was the aim of this research. In this work, the effects of different heat treatments such as annealing, solid solution, peak ageing and over ageing before MDF on mechanical properties and microstructure of the alloy were studied. Microstructure evolution during severe plastic deformation was considerably affected by the precipitates and non-shearable particles. On the other hand, the severe plastic deformation had different effects on precipitates in the microstructure. Fragmentation, scattering and...
Marker-less versus marker-based driven musculoskeletal models of the spine during static load-handling activities
, Article Journal of Biomechanics ; Volume 112 , 2020 ; Arjmand, N ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Evaluation of workers’ body posture in workstations is a prerequisite to estimate spinal loads and assess risk of injury for the subsequent design of preventive interventions. The Microsoft Kinect™ sensor is, in this regard, advantageous over the traditional skin-marker-based optical motion capture systems for being marker-less, portable, cost-effective, and easy-to-use in real workplaces. While several studies have demonstrated the validity/reliability of the Kinect for posture measurements especially during gait trials, its capability to adequately drive a detailed spine musculoskeletal model for injury risk assessments remains to be investigated. Lumbosacral (L5-S1) load predictions of a...
Alteration of initial and residual healing potential of asphalt binders due to aging, rejuvenation, and polymer modification
, Article Road Materials and Pavement Design ; 2020 ; Tabatabaee, N ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Asphalt binders are known to exhibit an inherent ability to repair damage. Such self-healing potentially affects the fatigue damage performance of bituminous materials. There are contradicting findings about the effects of aging and polymer modification on healing. The effectiveness of rejuvenating agents also has not been sufficiently addressed. In the present study, three healing indices have been defined to provide a more complete representation with which to quantify the healing potential of binders. These indices have been defined using damage characteristic curves derived from interrupted linear amplitude sweep tests. Initial healing (IH) describes the immediate reduction in the damage...
Investigation of the gamma-ray shielding performance of the B2O3-Bi2O3-ZnO-Li2O glasses based on the monte carlo approach
, Article Radiation Physics and Chemistry ; Volume 189 , 2021 ; 0969806X (ISSN) ; Hosseini, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The purpose of this article is to investigate the shielding performance of the B2O3-Bi2O3-ZnO-Li2O glasses against the gamma-ray. To this end, the attenuation parameters of the gamma-ray inside the B2O3-Bi2O3-ZnO-Li2O glasses were evaluated in the energy range of 200–1500 keV. It was found that the mass attenuation coefficient of the composites increases with increasing the Li2O content. The relative percent deviation between the results of simulation using the MCNPX and XCOM database in most cases was less than 2%. Additionally, the Mean Free Path (MFP) and Half-Value Layer (HVL) parameters were evaluated, and the shielding efficiency of samples was compared with some conventional shielding...
MDA-based methodologies: An analytical survey
, Article 4th European Conference on Model Driven Architecture - Foundations and Applications, ECMDA-FA 2008, Berlin, 9 June 2008 through 13 June 2008 ; Volume 5095 LNCS , 2008 , Pages 419-431 ; 03029743 (ISSN); 3540690956 (ISBN); 9783540690955 (ISBN) ; Ramsin, R ; Sharif University of Technology
Springer Verlag
2008
Abstract
Model-Driven Development (MDD) has become a familiar software engineering term in recent years, thanks to the profound influence of the Model Driven Architecture (MDA). Yet MDD, like MDA itself, defines a general framework, and as such is a generic approach rather than a concrete development methodology. Methodology support for MDA has been rather slow in coming, yet even though several MDA-based methodologies have emerged, they have not been objectively analyzed yet. The need remains for a critical appraisal of these methodologies, mainly aimed at identifying their achievements, and the shortcomings that should be addressed. We provide a review of several prominent MDA-based methodologies,...
Alteration of initial and residual healing potential of asphalt binders due to aging, rejuvenation, and polymer modification
, Article Road Materials and Pavement Design ; Volume 23, Issue 2 , 2022 , Pages 287-307 ; 14680629 (ISSN) ; Tabatabaee, N ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Asphalt binders are known to exhibit an inherent ability to repair damage. Such self-healing potentially affects the fatigue damage performance of bituminous materials. There are contradicting findings about the effects of aging and polymer modification on healing. The effectiveness of rejuvenating agents also has not been sufficiently addressed. In the present study, three healing indices have been defined to provide a more complete representation with which to quantify the healing potential of binders. These indices have been defined using damage characteristic curves derived from interrupted linear amplitude sweep tests. Initial healing (IH) describes the immediate reduction in the damage...
Performance Enhancement of Enterprise Storage Systems Using a Markov-Based Prefetching Method
, M.Sc. Thesis Sharif University of Technology ; Asadi, Hossein (Supervisor)
Abstract
With increasing rate of digital information in the world, design, configuration, and networking of enterprise storage systems has become an essential part in designing data centers. The performance of data storage systems in serving incoming requests is one of the major parameters of such systems. A major metric to measure performance is response time. This parameter is, in particular, crucial in enterprise applications such as financial, credit, multimedia, and real-time applications. A common approach to enhance the performance of enterprise storage systems is improving the hit ratio of the system global memory using prefetching technique. Using prefetching technique, a data block is...
Management of Storage Resources, Power, and Performance in Enterprise Storage Systems Using Prefetching Method
, M.Sc. Thesis Sharif University of Technology ; Asadi, Hossein (Supervisor)
Abstract
Nowadays, enterprise storage systems are widely used in data centers such as databases, servers, and bank institutes. Due to mechanical activity of disk drives, these systems are one of the most power consumptive components in data centers. Prefetching and RAID, which are employed to enhance performance, are widely used in data storage systems. These two methods, however, impose significant energy overhead to the system due to the increased disk activity. In this thesis, we first elaborate shortcomings of prefetching and RAID methods. Then, we propose a new energy efficient and RAID-compatible prefetching method (LPTAP), which aims at improving performance and energy consumption. To evaluate...
Evaluation of Seismic Criteria and Random Parameters on Fragility Curves of RC Frames
, Ph.D. Dissertation Sharif University of Technology ; Bakhshi, Ali (Supervisor)
Abstract
There are many parameters which are utilized to obtain a more reasonable performance for structures under earthquake excitations in seismic provisions. It is well recognized that the main character to design of structures under seismic excitation is probabilistic rather than deterministic; therefore, it should be determined if the probability of structural damages is decreased when such parameters change in design of structures. In this thesis, fragility curves are developed in order to evaluate these parameters. Fragility curves are employed for various probability parameters. These diagrams are utilized to demonstrate when a coefficient or a number of parameters are used to improve...
Evaluating Availability of Backend Logic in Enterprise Storage Systems
, M.Sc. Thesis Sharif University of Technology ; Asadi, Hossein (Supervisor)
Abstract
Data storage systems are an essential part of any Information Technology (IT) infrastructure. Unavailability of these systems can directly lead to service disruption to customers and can be very costly in enterprise applications such as ebanking, online reservation systems, and mobile services. Modeling availability of disk subsystem is a major step in design of data storage systems. Previous modeling techniques have mainly focused on data unavailability or data loss due to double or multiple disk failures. In this thesis, we present both simulation and analytical modeling techniques to investigate the effect of serviceability on the overall availability of disk subsystems. The proposed...
A Reconfigurable Architecture Using Non-voltatile Memories
, M.Sc. Thesis Sharif University of Technology ; Asadi, Hossein (Supervisor)
Abstract
In recent years, emerging Non-Volatile Memories (NVMs) have become promising alternatives for existing memory technologies. Due to shortcomings of SRAM memory in nanometer era,NVMs such as Phase-Change Memory (PCM) can be used in configuration memories of Field-Programmable Gate Arrays (FPGAs). Despite prominent features of emerging NVMs, they suffer from high write-power, high write-latency, and limited number of reliable write opera-tions. In addition, a dedicated Peripheral Circuit (PC) which is required to convert the NVM state to the equivalent voltage level can impose significant area and power overheads to FPGAs.In this thesis, a reliable power-efficient hybrid architecture employing...