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Network Design to Alleviate Chaos in the Transportation Network Flows: Cases of Deterministic and Uncertain Supply
, M.Sc. Thesis Sharif University of Technology ; Pourzahedi, Hossein (Supervisor)
Abstract
Transportation networks are considered as complex systems, and in many cases they behave in such an irregular and unexpected manner. Such complexities cause problems in studying the behavior of these systems. An example of such complexities is chaos in the network flows. On the other hand, the behavior of these networks is highly affected by the incidents like accidents and bad weather. Such events affect the level of service and travel time reliability of the networks. In this research, a dynamical approach to traffic assignment has been chosen to model chaos and uncertainties in the network. By using this approach for modeling flow evolution, edge of chaos and uncertainty in supply and...
Converting the Organic Constituents of the Li-ion Batteries to Added-value Species with the Possibility of Removing the Environmental Pollutants
, M.Sc. Thesis Sharif University of Technology ; Fotovat, Farzam (Supervisor)
Abstract
During the last few years, the number of electric devices using lithium-ion batteries as a source of energy has increased drastically. The lifespan of these batteries is very short (2-3 years) and according to the statistics only 25% of which is recycled. However, considering the variety of materials used in these batteries, recycling them can be highly gainful. One of the technical challenges in the way of recycling Li-ion batteries is the presence of polyvinylidene fluoride (PVDF), that besides raising issues during recycling processes causes the production of toxic fluorine or hydrogen fluoride effluents. The second issue is the presence of metals with high oxidation states in these...
Mitigating ferroresonance in coupling capacitor voltage transformers with ferroresonance suppressing circuits
, Article IEEE EUROCON 2009, EUROCON 2009, St. Petersburg, 18 May 2009 through 23 May 2009 ; 2009 , Pages 817-822 ; 9781424438617 (ISBN) ; Babazadeh, D ; Esmaeilnia Shirvani, R ; Purrezagholi, M ; Sharif University of Technology
2009
Abstract
In order to restrain ferroresonance in coupling capacitor voltage transformers (CCVT), two kinds of ferroresonance suppression circuits (FSCs) , are proposed in this paper: the resonant type, the fastsaturation reactor type which are connected to secondary side of CCVTs. Frequency domain analyses, for voltage ratio magnitude, are carried out for CCVTs to obtain preferable FSC. Furthermore, using surge suppressors such as metal oxide varistors (MOV) to improve the performance of the FSCs is investigated. Time domain simulations demonstrate that ferroresonance can be cleared in few cycles in presence of FSCs. The Electromagnetic Transients Program (EMTP) is used for modeling and fine-tuning...
Simulation and Acceleration of Image Reconstruction for a Typical PET Imaging System Using GPU
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Nasser (Supervisor) ; Vosughi Vahdat, Bijan (Supervisor)
Abstract
Positron Emmision Tomography is one of the most important methods in molecular imaging field. One of the challenges over PET imaging is the resolution of reconstructed images. To overcome this problem, one can use more exact image reconstruction methods called, iterative methods. It has been showed that Iterative methods like MLEM have advantages over Analytical ones. Main drawback of iterative methods is time consuming computation. Then you should reduce the image reconstruction’s time for clinical time constraints. Using Graphic Proccessing Unit for accelerating computational works, raised in recent years. In this work, we used GPU for accelerating pet image reconstruction and simulation...
The relationship between an EFL teacher's gender and students' willingness to communicate
, Article International Journal of Communication and Linguistic Studies ; Volume 10, Issue 4 , 2013 , Pages 17-29 ; 23277882 (ISSN) ; Pakzadian, S. S
Common Ground Publishing
2013
Abstract
Learning a foreign language encompasses a process of trial and error that can lead to the progression of the learner's interlanguage, meaning that the learners make use of their language knowledge that receives feedback and brings about progress through diagnosis of the problems and being corrected by the teacher. Therefore, there exists a need to analyze the underlying reasons causing the students to remain taciturn with a low willingness to communicate (WTC) during a language class. There has been much work done investigating the role of the learner's stable personal characteristics (traits) along with their situational changes at a specific time (states) that influence the student's...
Design and development of a miniaturized roto-translational motion platform for microaerial vehicle identification
, Article IEEE Aerospace and Electronic Systems Magazine ; Volume 39, Issue 12 , 2024 , Pages 24-35 ; 08858985 (ISSN) ; Pourtakdoust, S. H ; Mousavi, S. M. S
IEEE
2024
Abstract
Accurate system identification (SI) is essential for flight controller design of unmanned aerial vehicles and microaerial vehicles (MAVs). SI can be performed either in frequency or time domain using flight test data. As flight testing is often costly and may even lead to catastrophic events before some flight stability analysis is at hand, a low-cost 5 degree-of-freedom free motion platform (FMP) is designed and used for initial identification of MAVs via wind tunnel testing. A typical MAV is constructed as a test case and equipped with inertial sensors for testing and validation purposes. The proposed FMP allows for both rotational as well as translational motions that in turn provide for...
An automated simple algorithm for realistic pore network extraction from micro-tomography images
, Article Journal of Petroleum Science and Engineering ; Vol. 123, issue , 2014 , pp. 164-171 ; ISSN: 09204105 ; Jamshidi, S ; Salehi, S
2014
Abstract
Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images...
Discrimination of heart arrhythmias using novel features in heart rate phase space
, Article Computing in Cardiology ; Volume 40 , Sept , 2013 , Pages 1035-1038 ; 23258861 (ISSN); 9781479908844 (ISBN) ; Rezaei, S ; Salavatian, S
2013
Abstract
In this paper, we try to recognize and distinguish different groups of arrhythmia using novel features which have been obtained from the heart rate's phase space in recent years. For this purpose, we used Triangular Phase Space Mapping (TPSM) and Parabolic Phase Space Mapping (PPSM). For recognition, we used three groups of 15 subjects using the Physionet database (Arrhythmia, Congestive Heart Failure (CHF), and Atrial Fibrillation (AF)) with Normal Sinus Rhythm (NSR). The obtained features discriminate arrhythmia from NSR by p
An intelligent hybrid classification algorithm integrating fuzzy rule-based extraction and harmony search optimization: Medical diagnosis applications
, Article Knowledge-Based Systems ; Volume 220 , 2021 ; 09507051 (ISSN) ; Abdullah, S ; Akhavan Niaki, S. T ; Banihashemi, S ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Uncertainty is a critical factor in medical datasets needed to be overcome for increasing diagnosis efficiency. This paper proposes an intelligent classification algorithm comprising a fuzzy rule-based approach, a harmony search (HS) algorithm, and a heuristic algorithm to classify medical datasets intelligently. Two fuzzy approaches, as well as orthogonal and triangular fuzzy sets, are first utilized to define the attributes of data. Then, an HS algorithm is integrated with a heuristic to generate fuzzy rules to select the best rules in the fuzzy rule-based systems. Moreover, to improve the performance of the proposed classification approach, a three-phase parameter tuning approach is...
Performance evaluation of shared hosting security methods
, Article Proc. of the 11th IEEE Int. Conference on Trust, Security and Privacy in Computing and Communications, TrustCom-2012 - 11th IEEE Int. Conference on Ubiquitous Computing and Communications ; 2012 , Pages 1310-1315 ; 9780769547459 (ISBN) ; Arshad, S ; Khoshkdahan, S ; Sharif University of Technology
2012
Abstract
Shared hosting is a kind of web hosting in which multiple websites reside on one webserver. It is cost-effective and makes the administration easier for websites' owners. However, shared hosting has some performance and security issues. In default shared hosting configuration, all websites' scripts are executed under the webserver's user account regardless of their owners. Therefore, a website is able to access other websites' resources. This security problem arises from lack of proper isolation between different websites hosted on the same webserver. In this survey, we have examined different methods for handling mentioned security issue. Also we evaluated the performance of mentioned...
The behaviour of an artificially cemented sandy gravel
, Article Geotechnical and Geological Engineering ; Volume 23, Issue 5 , 2005 , Pages 537-560 ; 09603182 (ISSN) ; Hosseini, S. M ; Toll, D. G ; Yasrebi, S. S ; Sharif University of Technology
2005
Abstract
The major section of the city of Tehran, Iran has been developed on cemented coarse-grained alluvium. This deposit consists of gravely sand to sandy gravel with some cobbles and is dominantly cemented by carbonaceous materials. In order to understand the mechanical behaviour of this soil, a series of undrained triaxial compression tests and unconfined compression tests were performed on uncemented and artificially cemented samples. Portland cement type I was used as the cementation agent for preparing artificially cemented samples. Uncemented samples and lightly cemented samples (1.5% cement) tested at high confining pressure showed contractive behaviour accompanied with positive excess pore...
An imperialist competitive algorithm approach for multi-objective optimization of direct coupling photovoltaic-electrolyzer systems
, Article International Journal of Hydrogen Energy ; Vol. 39, Issue 33 , 11 November , 2014 , pp. 18743-18757 ; ISSN: 03603199 ; Sayedin, F ; Khavas, S. S
2014
Abstract
In the context of sustainable clean hydrogen production pathways, photovoltaic-electrolyzer systems are one of the most promising alternatives for acquiring hydrogen from renewable energy sources. In fact, determining the optimal set of design and operating variables are always a key issue while coupling directly renewable electricity sources to PEM electrolyzers. Few previous studies have attempted to find the optimal size and operational condition of directly coupled photovoltaic-electrolyzer (PV/El) systems in order to maximize the hydrogen production or to minimize energy transfer loss between photovoltaic devices and the electrolyzer. Nevertheless an easy and efficient approach still...
Kalman filter based packet loss replacement in presence of additive noise
, Article 2012 25th IEEE Canadian Conference on Electrical and Computer Engineering: Vision for a Greener Future, CCECE 2012 ; 2012 ; 9781467314336 (ISBN) ; Ghorshi, S ; Tahaei, A
2012
Abstract
A major problem in real-time packet-based communication systems, is misrouted or delayed packets which results in degraded perceived voice quality. If packets are not available on time, the packets are considered as lost. The easiest solution in a network terminal receiver is to replace silence for the duration of lost speech segments. In a high quality communication system, to avoid degradation in speech quality due to packet loss, a suitable method or algorithm is needed to replace the missing segments of speech. In this paper, we introduce an adaptive filter for replacement of lost speech segment. In this method Kalman filter as a state-space based method will be used to predict the...
Investigation of Mesh Sensitivity Influence to Determine Crack Characteristic by Finite Element Methods
, Article Journal of Failure Analysis and Prevention ; Volume 16, Issue 3 , 2016 , Pages 506-512 ; 15477029 (ISSN) ; Mirjavadi, S. S ; Asli, S. A ; Sharif University of Technology
Springer New York LLC
2016
Abstract
In this research, an extended finite element model has been investigated. Investigation of opening and closure stress always has been one of the difficult parameters to analysis of results; therefore, the utilization of finite element methods would be a good and logical alternative for this purpose. In addition, linear elastic fracture criteria are used for validation of numerical results from the simulation. In this work, a detailed analysis of the influence of different parameters in the results of a specific specimen with a semi-elliptical tooling groove in terms of closure and opening stress is presented, and the impact of optimum element size in fracture characteristic in various load...
Investigation of the effect of nanosilica on rheological, thermal, mechanical, structural, and piezoelectric properties of poly(vinylidene fluoride) nanofibers fabricated using an electrospinning technique
, Article Industrial and Engineering Chemistry Research ; Volume 56, Issue 44 , 2017 , Pages 12596-12607 ; 08885885 (ISSN) ; Ahmad Ramazani, S. A ; Talebi, S ; Fattahpour, S ; Hasany, M ; Sharif University of Technology
2017
Abstract
The effects of different nano-SiO2 contents on the rheological properties of poly(vinylidene fluoride) (PVDF) solution and mechanical, thermal, structural, and piezoelectric properties of composite nanofibers were investigated. Results showed an increase in fiber diameter (∼125 to 350 nm) and ∼450% increase in tensile strength as the content of nano-SiO2 particles increased. The degree of crystallinity decreased by 19% as the nano-SiO2 content increased by 2% (w/w). Further investigation demonstrated that silica could significantly improve the piezoelectric properties of PVDF nanofibers as the output voltage showed an increase in the presence of silica attributed to change in the crystalline...
Burden of transport-related injuries in the eastern mediterranean region: A systematic analysis for the global burden of disease study 2017
, Article Archives of Iranian Medicine ; Volume 24, Issue 7 , 2021 , Pages 512-525 ; 10292977 (ISSN) ; Sullman, M. J. M ; Lajunen, T ; Hill, T ; Almasi Hashiani, A ; Moradi Lakeh, M ; Farzadfar, F ; Sepanlou, S. G ; Abu-Gharbieh, E ; Aghamolaei, T ; Ahmad, T ; Alghnam, S. A ; Al-Hajj, S ; Alipour, V ; Aljunid, S. M ; Anjomshoa, M ; Ansari Moghaddam, A ; Arabloo, J ; Bayati, M ; Bedi, N ; Bendak, S ; Bhutta, Z. A ; Bijani, A ; Dahlawi, S. M. A ; Dianatinasab, M ; Forooshani, Z. S. D ; Elhabashy, H. R ; Zeydi, A. E ; Eskandarieh, S ; Ghafourifard, M ; Ghashghaee, A ; Grivna, M ; Gubari, M. I. M ; Hamadeh, R. R ; Hamidi, S ; Hayat, K ; Rad, E. H ; Hosseinzadeh, M ; Househ, M ; Naghibi, S. S ; Jahani, M. A ; Kalankesh, L. R ; Kalhor, R ; Kamel, I ; Khammarnia, M ; Khan, M ; Khazaie, H ; Komaki, H ; Lahimchi, A ; Madadin, M ; Maleki, S ; Manafi, N ; Mansour Ghanaei, F ; Mansournia, M. A ; Menezes, R. G ; Mohammad, Y ; Mohammadian Hafshejani, A ; Mohebi, F ; Moradi, G ; Moradzadeh, R ; Mousavi, S. M ; Naderi, M ; Nikbakhsh, R ; Pakshir, K ; Pourshams, A ; Rabiee, N ; Rafiei, A ; Rawassizadeh, R ; Rezapour, A ; Saddik, B ; Moghaddam, S. S ; Salamati, P ; Salem, M. R ; Salem, H ; Samy, A. M ; Sathian, B ; Shahabi, S ; Shaikh, M. A ; Shams-Beyranvand, M ; Shamsizadeh, M ; Sobhiyeh, M. R ; Soheili, A ; Tehrani Banihashemi, A ; Waheed, Y ; Yusefzadeh, H ; Moghadam, T. Z ; Zaki, L ; Zamani, M ; Zandian, H ; Malekzadeh, R ; Naghavi, M ; Sharif University of Technology
Academy of Medical Sciences of I.R. Iran
2021
Abstract
Background: Transport-related injuries (TIs) are a substantial public health concern for all regions of the world. The present study quantified the burden of TIs and deaths in the Eastern Mediterranean region (EMR) in 2017 by sex and age. Methods: TIs and deaths were estimated by age, sex, country, and year using Cause of Death Ensemble modelling (CODEm) and DisMod-MR 2.1. Disability-adjusted life years (DALYs), which quantify the total burden of years lost due to premature death or disability, were also estimated per 100 000 population. All estimates were reported along with their corresponding 95% uncertainty intervals (UIs). Results: In 2017, there were 5.5 million (UI 4.9-6.2)...
A method for real-time safe navigation in noisy environments
, Article 2013 18th International Conference on Methods and Models in Automation and Robotics, MMAR 2013, Miedzyzdroje ; 2013 , Pages 329-333 ; 9781467355063 (ISBN) ; Kamali, E ; Niknezhad, M. R ; Monfared, S. S. M. S ; Sharif University of Technology
2013
Abstract
The challenge of finding an optimized and reliable path dates back to emersion of mobile robots. Several approaches have been developed that have partially answered this need. Satisfying results in previous implementations has led to an increased utilization of sampling-based motion planning algorithms in recent years, especially in high degrees of freedom (DOF), fast evolving environments. Another advantage of these algorithms is their probabilistic completeness that guarantees delivery of a path in sufficient time, if one exists. On the other hand, sampling based motion planners leave no comment on safety of the planned path. This paper suggests biasing the Rapidly-exploring Random Trees...
A generalization of the swartz equality
, Article Glasgow Mathematical Journal ; Vol. 56, issue. 2 , May , 2014 , pp. 381-386 ; ISSN: 00170895 ; Fakhari, S. A. S ; Yassemi, S ; Sharif University of Technology
2014
Abstract
For a given (d-1)-dimensional simplicial complex Γ, we denote its h-vector by h(Γ)=(h 0(Γ),h 1(Γ),...,hd (Γ)) and set h -1(Γ)=0. The known Swartz equality implies that if Δ is a (d-1)-dimensional Buchsbaum simplicial complex over a field, then for every 0 ≤ i ≤ d, the inequality ihi (Δ)+(d-i+1)h i-1(Δ) ≥ 0 holds true. In this paper, by using these inequalities, we give a simple proof for a result of Terai (N. Terai, On h-vectors of Buchsbaum Stanley-Reisner rings, Hokkaido Math. J. 25(1) (1996), 137-148) on the h-vectors of Buchsbaum simplicial complexes. We then generalize the Swartz equality (E. Swartz, Lower bounds for h-vectors of k-CM, independence, and broken circuit complexes, SIAM J....
Hardware-in-the-loop optimization of an active vibration controller in a flexible beam structure using evolutionary algorithms
, Article Journal of Intelligent Material Systems and Structures ; Vol. 25, issue. 10 , 2014 , p. 1211-1223 ; Hosseini Kordkheili, S. A ; Afshari, S. S ; Sharif University of Technology
2014
Abstract
In this study, active vibration control of a cantilevered flexible beam structure equipped with bonded piezoelectric sensor/actuators is investigated. The linear quadratic regulator technique together with an observer is adopted to design the controller as well as to provide the full-state feedback. Two different approaches are subsequently used for simultaneously integrated optimization of the controller and observer parameters. In the first approach, a linear experimental model of the system is obtained using identification techniques, and the optimization is then performed based on a computer simulation of the system. However, in the second approach, a hardware-in-the-loop optimization...
An efficient inference in meanfield approximation by adaptive manifold filtering: (Machine learning & data mining)
, Article Proceedings of the 4th International Conference on Computer and Knowledge Engineering, ICCKE 2014 ; 2014 , p. 581-585 ; Ramezanpur, S ; Kasaei, S ; Sanaei, E ; Sharif University of Technology
2014
Abstract
A new method for speeding up the approximate maximum posterior marginal (MPM) inference in meanfield approximation of a fully connected graph is introduced. Weight of graph edges is measured by mixture of Gaussian kernels. This fully connected graph is used for segmentation of image data. The bottleneck of the inference in meanfield approximation is where the similar bilateral filtering is needed for updating the marginal in the message passing step. To speed up the inference, the adaptive manifold high dimensional Gaussian filter is used. As its time complexity is 0(ND), it leads to accelerating the marginal update in the message passing step. Its time complexity is linear and relative to...