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javidi-sofiani--mahyar
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, M.Sc. Thesis Sharif University of Technology ; Ramezani Saadat, Ahmad (Supervisor)
Abstract
Polymer flooding can yield considerable increase in percentage recovery. However, there are limitations with the existing polymer flooding technology, such as thermal, mechanical, bacterial degradation, surface absorption and undesirable plugging. A novel nanocore shell structure of polyacrylamide and polystyrene designed and prepared to intellectually control mobility ratio in oil reservoirs and overcome weakness and limitations of classical polymer flooding. Polyacrylamide particles have been obtained using spray drying of dilute solution of polyacrylamide. Then, polystyrene shell has been produced on polyacryamide particles by in-situ polymerization of styrene monomer in hydrophobic...
A novel design of the KASUMI block cipher using one-hot residue number system
, Article Middle East Journal of Scientific Research ; Volume 11, Issue 8 , 2012 , Pages 1078-1086 ; 19909233 (ISSN) ; Sharif University of Technology
2012
Abstract
The KASUMI block cipher is used for the cellular communications networks and safety of many wireless standards. Third generation cellular network technology (3G) permits to transmit information, voice and video at very high data rates never seen before that will revolutionize personal communications and information exchange. On the other hand, Residue Number System (RNS) is a modular representation and is evidenced to be serviceable equipment in many applications which need high-speed computations and high-performance components. RNS is a non-weighted and integer number system that can support secure, highspeed, low-power, parallel and carry-free arithmetic. For attaining the most...
Reliable and high-speed KASUMI block cipher by residue number system code
, Article World Applied Sciences Journal ; Volume 17, Issue 9 , 2012 , Pages 1149-1158 ; 18184952 (ISSN) ; Sharif University of Technology
2012
Abstract
Third generation cellular network technology (3G) can revolutionize communications and data exchanges between many people in a more overwhelming fashion than 2G and 2.5G networks did. The 3G UMTS, the 3G GSM and the 3G GPRS rely on the KASUMI block cipher. Therefore, increasing speed, decreasing power consumption and error detection/correction are the major concerns of the KASUMI algorithm and its generation. On the other hand, Residue Number System is a non-weighted number system and it is currently considered as an important method for high-speed, low-power, parallel and carry-free arithmetic realizations. Redundant Residue Number System is an extension of RNS that also supports error...
Business Process Oriented Software Engineering
, M.Sc. Thesis Sharif University of Technology ; Habibi, Jafar (Supervisor)
Abstract
Enterprises are founded according to their business processes based on its targets. For implementing an Information System, first it is required to analyze, design and model of the processes based on a specific methodology.The methodologies of software engineering usually used to be function oriented however object oriented is usual and practical todays. Analyzing the business processes according to one of these two concepts has some problems, however merging these two concepts, makes a powerful method in analyzing and designing of a system more easily and accurately.Some software development methodologies consider these two aspects in a way, however working with them has many complexities...
Quantitative Rsk Assessment and Accident Frequency Determination Based on Fuzzy Logic with Shazand Oil Refinery Accident Case Study
, M.Sc. Thesis Sharif University of Technology ; Rashtchian, Davoud (Supervisor)
Abstract
Today, Quantitative Risk Assessment (QRA) has become an efficient tool in decision making for safety and process experts. To assess the risk of any accident scenario, it is necessary that the probability of that event be determined in addition to estimating the probable consequences. Event tree and fault tree analysis are known to be the standard tools for calculating the frequency of incident outcomes.
In this research, a new method based on Markov chin and Fuzzy theory is presented to estimate the occurrence probability of events. A one of important parameter which has sufficient effect on probability of incident frequency, is inspection and maintenance interval. in this research...
In this research, a new method based on Markov chin and Fuzzy theory is presented to estimate the occurrence probability of events. A one of important parameter which has sufficient effect on probability of incident frequency, is inspection and maintenance interval. in this research...
Short-Circuit Failure Detection in Series-Connected IGBTs for Reliability Improvements
, M.Sc. Thesis Sharif University of Technology ; Kaboli, Shahriyar (Supervisor)
Abstract
In high-voltage power electronics systems where the supply voltage exceeds the maximum voltage these devices can withstand, series-connected IGBTs with TO-247 packaging and simultaneous gate command circuitry are used to create a high-voltage switch with an on and off time equivalent to a single IGBT. By considering voltage protection circuits for the series IGBTs, the large supply voltage is approximately evenly divided among the series switches. The resulting high-voltage switch has smaller conduction and switching losses compared to single high-voltage switches, has a lower finished price, and its turn-on time is much shorter due to their smaller gate-emitter junction capacitance...
Dielectrophoretic interaction of two particles in a uniform electric field
, Article Microsystem Technologies ; Volume 25, Issue 7 , 2019 , Pages 2699-2711 ; 09467076 (ISSN) ; Moghimi Zand, M ; Dastani, K ; Sharif University of Technology
Springer Verlag
2019
Abstract
The local electric field distorsion induced by a dielectric particle leads to particle–particle interactions and assembly which is very interesting for their useful applications on microfluidic devices. Particles behavior becomes more complicated if several particles interact at the same time. This paper presents a comprehensive numerical analysis of the assembly and particle–particle interactions for two similar and dissimilar dielectric particles immersed in a dielectric fluid using the immersed interface method based on two-dimensional direct-current dielectrophoresis. The immersed interface method is a finite-difference (or finite element) based numerical method which its key advantage...
UCS-NT: An unbiased compressive sensing framework for Network Tomography
, Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings ; 2013 , Pages 4534-4538 ; 15206149 (ISSN) ; 9781479903566 (ISBN) ; Rabiee, H. R ; Hashemifar, Z. S ; Sharif University of Technology
2013
Abstract
This paper addresses the problem of recovering sparse link vectors with network topological constraints that is motivated by network inference and tomography applications. We propose a novel framework called UCS-NT in the context of compressive sensing for sparse recovery in networks. In order to efficiently recover sparse specification of link vectors, we construct a feasible measurement matrix using this framework through connected paths. It is theoretically shown that, only O(k log(n)) path measurements are sufficient for uniquely recovering any k-sparse link vector. Moreover, extensive simulations demonstrate that this framework would converge to an accurate solution for a wide class of...
Detection of top-K central nodes in social networks: A compressive sensing approach
, Article Proceedings of the 2015 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining, ASONAM 2015, 25 August 2015 through 28 August 2015 ; 2015 , Pages 902-909 ; 9781450338547 (ISBN) ; Pei, J ; Tang, J ; Silvestri, F ; Sharif University of Technology
Association for Computing Machinery, Inc
2015
Abstract
In analysing the structural organization of a social network, identifying important nodes has been a fundamental problem. The concept of network centrality deals with the assessment of the relative importance of a particular node within the network. Most of the traditional network centrality definitions have a high computational cost and require full knowledge of network topological structure. On the one hand, in many applications we are only interested in detecting the top-k central nodes of the network with the largest values considering a specific centrality metric. On the other hand, it is not feasible to efficiently identify central nodes in a large real-world social network via...
A multivariable model for estimation of vapor cloud explosion occurrence possibility based on a Fuzzy logic approach for flammable materials
, Article Journal of Loss Prevention in the Process Industries ; Volume 33 , January , 2015 , Pages 140-150 ; 09504230 (ISSN) ; Abdolhamidzadeh, B ; Reniers, G ; Rashtchian, D ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this paper, a new method based on Fuzzy theory is presented to estimate the occurrence possibility of vapor cloud explosion (VCE) of flammable materials. This new method helps the analyst to overcome some uncertainties associated with estimating VCE possibility with the Event Tree (ET) technique. In this multi-variable model, the physical properties of the released material and the characteristics of the surrounding environment are used as the parameters specifying the occurrence possibility of intermediate events leading to a VCE. Factors such as area classification, degree of congestion of a plant and release rate are notably affecting the output results. Moreover, the proposed method...
A fast optimization method for extension of depth-of-field in three-dimensional task-specific imaging systems
, Article IEEE/OSA Journal of Display Technology ; Volume 6, Issue 10 , August , 2010 , Pages 412-421 ; 1551319X (ISSN) ; Kavehvash, Z ; Mehrany, K ; Javidi, B ; Sharif University of Technology
2010
Abstract
In this paper, we present a novel approach to generate images of extended depth-of-field (DOF) to support realization of three-dimensional (3D) imaging systems such as integral imaging. In our approach in extending the DOF, we take advantage of the spatial frequency spectrum of the object specific to the task in hand. The pupil function is thus engineered in such a fashion that the modulation transfer function (MTF) is maximized only in these selected spatial frequencies. We extract these high energy spatial frequencies using the principal component analysis (PCA) method. Moreover, given the need for many pupil function engineering steps in 3D imaging systems, we have constructed an...
Compressed sensing in cyber physical social systems
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 10760 LNCS , 2018 , Pages 287-305 ; 03029743 (ISSN) ; Ghalebi, K. E ; Movaghar, A ; Mahyar, H ; Sharif University of Technology
2018
Abstract
We overview the main results in Compressed Sensing and Social Networks, and discuss the impact they have on Cyber Physical Social Systems (CPSS), which are currently emerging on top of the Internet of Things. Moreover, inspired by randomized Gossip Protocols, we introduce TopGossip, a new compressed-sensing algorithm for the prediction of the top-k most influential nodes in a social network. TopGossip is able to make this prediction by sampling only a relatively small portion of the social network, and without having any prior knowledge of the network structure itself, except for its set of nodes. Our experimental results on three well-known benchmarks, Facebook, Twitter, and Barabási,...
Design and Implementation of a Distributed System for Energy Management in a Hybrid-Energy Building
, M.Sc. Thesis Sharif University of Technology ; Goudarzi, Maziar (Supervisor)
Abstract
Solar panels are still rather expensive equipments. At current electricity prices, it takes several years to return the investment made to install them in a household. Smarter use of their produced energy can help reduce this break-even time, and hence, would motivate more households to be willing to install and use them which would finally result in a more sustainable society with less reliance on fossil fuels. Electricity prices usually differ at different times of day with the common, but unfortunate, property that the price is maximized at evenings when the solar energy production is minimal or non-existent while at the peak production of the solar panels, i.e., around noon, the price is...
Preparation and characterization of self-stimuli conductive nerve regeneration conduit using co-electrospun nanofibers filled with gelatin-chitosan hydrogels containing polyaniline-graphene-ZnO nanoparticles
, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 73, Issue 3 , 2024 , Pages 165-175 ; 00914037 (ISSN) ; Ramazani Saadatabadi, A ; Sadrnezhaad, K ; Najmoddin, N ; Sharif University of Technology
2024
Abstract
The core-shell structure conduit with conductive, antibacterial, and highly piezoelectric properties was designed and fabricated by a multi-step process. First, the shell structure was fabricated by rolling the co-electrospun mats of polycaprolactone/polyvinylidene fluoride and gelatin incorporated with polyaniline/graphene (PAG) nanocomposites. Then, the fabricated mats were filled with gelatin/chitosan hydrogels containing PAG and zinc oxide nanoparticles. Characterization of the intermediate materials and the final conduit revealed high electrical conductivity and remarkable output voltage for shell and core materials. MTT assay and antibacterial tests confirmed bioactivity and...
Conductive nerve conduit with piezoelectric properties for enhanced PC12 differentiation
, Article Scientific Reports ; Volume 13, Issue 1 , 2023 ; 20452322 (ISSN) ; Ramazani Saadatabadi, A ; Sadrnezhaad, S. K ; Najmoddin, N ; Sharif University of Technology
Nature Research
2023
Abstract
Restoration of nerve tissue remains highly challenging, mainly due to the limited regeneration capacity of the nervous system and the development of fibrosis. This limitation necessitates designing new nerve guidance channel to promote nerve repairing. In this study, we developed a novel core/shell conduit to induce PC12 differentiation. Co-electrospinning method was utilized to produce a fibrous shell containing polycaprolactone/polyvinylidene fluoride PCL/PVDF, gelatin and polyaniline/graphene (PAG) nanocomposite. The core section of the conduit was filled with chitosan–gelatin hydrogel containing PAG and ZnO nanoparticles. Such conduit shows antibacterial activity, electrical conductivity...
A data analytics framework for reliable bus arrival time prediction using artificial neural networks
, Article International Journal of Data Science and Analytics ; 2023 ; 2364415X (ISSN) ; Farjad, A ; Azadnia, A ; Javidi, M ; Chunduri, R ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2023
Abstract
The analysis of extensive vehicle location data in an urban bus system requires an efficient data-driven method so that its output can be used to improve both the information and operational reliabilities of the bus transit services. This research aims to design and implement an integrated model for forecasting bus arrival times using artificial intelligence techniques. The novelty of the research lies in developing an integrated predictive model based on a neural network computing framework to improve the results of fleet arrival forecasting models based on the estimation of travel time reliability. To validate the prediction model, extensive experiments are conducted to compare the...
Inherently safe and economically optimal design using multi-objective optimization: The case of a refrigeration cycle
, Article Process Safety and Environmental Protection ; Volume 104 , 2016 , Pages 254-267 ; 09575820 (ISSN) ; Shahhosseini, H. R ; Javidi, M ; Sharifzadeh, M ; Rashtchian, D ; Sharif University of Technology
Institution of Chemical Engineers
2016
Abstract
The economic viability of industrial processes strongly depends on their safe and reliable operation. The method of inherent safe process design enables systematic consideration of safety measures in order to ensure process safe operation at the early stages of process design. The challenge is that the economic measures that are often considered for the design of industrial processes are often incommensurable with the safety measures. In the present research, a novel framework is proposed in which the safety criteria are quantified based on consequence modeling and aggregated with the economic performance using multi-objective optimization programming. The developed methodology was applied...
Detection of Central Nodes in Social Networks
, Ph.D. Dissertation Sharif University of Technology ; Movaghar, Ali (Supervisor) ; Rabiee, Hamid Reza (Supervisor)
Abstract
In analyzing the structural organization of many real-world networks, identifying important nodes has been a fundamental problem. The network centrality concept deals with the assessment of the relative importance of network nodes based on specific criteria. Central nodes can play significant roles on the spread of influence and idea in social networks, the user activity in mobile phone networks, the contagion process in biological networks, and the bottlenecks in communication networks. High computational cost and the requirement of full knowledge about the network topology are the most significant obstacles for applying the general concept of network centrality to large real-world social...
An energy-efficient multi-sensor scheduling mechanism with QoS support for WBANs
, Article IEEE Wireless Communications and Networking Conference, WCNC ; 2014 , pp. 1703-1708 ; ISSN: 15253511 ; Ashtiani, F ; Javidi, T ; Nasiri-Kenari, M ; Vahdat, B. V ; Sharif University of Technology
2014
Abstract
In wireless body area networks (WBANs) it is necessary to devise an energy-efficient MAC scheduling mechanism which is capable of meeting strict QoS requirements. In this paper, special characteristics of WBAN channels, namely, the slow fading, the periodicity of fading, and the correlation among the channels have been exploited to formulate the sensor scheduling problem as a partially observable Markov decision problem (POMDP). Specific algorithms based on value iteration and pruning have been proposed in order to reduce the computational burden associated with the corresponding POMDP. The proposed scheduling mechanism is compared against a TDMA scheduling for a three-sensor network, and an...
A low-cost sparse recovery framework for weighted networks under compressive sensing
, Article Proceedings - 2015 IEEE International Conference on Smart City, SmartCity 2015, Held Jointly with 8th IEEE International Conference on Social Computing and Networking, SocialCom 2015, 5th IEEE International Conference on Sustainable Computing and Communications, SustainCom 2015, 2015 International Conference on Big Data Intelligence and Computing, DataCom 2015, 5th International Symposium on Cloud and Service Computing, SC2 2015, 19 December 2015 through 21 December 2015 ; 2015 , Pages 183-190 ; 9781509018932 (ISBN) ; Rabiee, H. R ; Movaghar, A ; Hasheminezhad, R ; Ghalebi, E ; Nazemian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
In this paper, motivated by network inference, we introduce a general framework, called LSR-Weighted, to efficiently recover sparse characteristic of links in weighted networks. The links in many real-world networks are not only binary entities, either present or not, but rather have associated weights that record their strengths relative to one another. Such models are generally described in terms of weighted networks. The LSR-Weighted framework uses a newly emerged paradigm in sparse signal recovery named compressive sensing. We study the problem of recovering sparse link vectors with network topological constraints over weighted networks. We evaluate performance of the proposed framework...