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ghareh-chamani--javad
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Toward a Method for Citation Recommendation in Citation Network
, M.Sc. Thesis Sharif University of Technology ; Habibi, Jafar (Supervisor)
Abstract
Study of real networks has become an important research task. Real networks appear in different domains such as social networks and biological networks. It is also possible to extract various networks from the set of scientific collaborations of published papers. In this project we investigate the analysis of citation network and co-authorship networks of scientific papers in order to find out a new method in citation recommendation of scientific papers. Presented method have some superior properties over existing citation recommendation systems like combining different fields for suggesting most relevant papers to user, in response of user’s input keywords. For presenting this method we...
Encryption Aware Query Processing for Data Outsourcing
, Ph.D. Dissertation Sharif University of Technology ; Jalili, Rasool (Supervisor)
Abstract
Data outsourcing provides cost-saving and availability guarantees. However, privacy and confidentiality issues, disappoint owners from outsourcing their data. Although solutions such as CryptDB and SDB tried to provide secure and practical systems, their enforced limitations, made them useless in practice. Inability in search on encrypted data, is one of the most important existing challenges in such systems. Furthermore, the overhead of mechanisms such as FHEs, removes them from considering for any practical system. Indeed, special purpose encryptions would be the only usable mechanisms for such purposes. However, their limited functionality does not support some important required...
Multi-User Dynamic Searchable Symmetric Encryption With Corrupted Participants
, Article IEEE Transactions on Dependable and Secure Computing ; Volume 20, Issue 1 , 2023 , Pages 114-130 ; 15455971 (ISSN) ; Wang, Y ; Papadopoulos, D ; Zhang, M ; Jalili, R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
We study the problem of multi-user dynamic searchable symmetric encryption (DMUSSE) where a data owner stores its encrypted documents on an untrusted remote server and wishes to selectively allow multiple users to access them by issuing keyword search queries. Specifically, we consider the case where some of the users may be corrupted and colluding with the server to extract additional information about the dataset (beyond what they have access to). We provide the first formal security definition for the dynamic setting as well as forward and backward privacy definitions. We then propose μSE, the first provably secure DMUSSE scheme and instantiate it in two versions, one based on oblivious...
Residual Stress Determination of Multi-pass Welding Process, Stress Relieving Procedures and Its Effect on Crack Propagation
, M.Sc. Thesis Sharif University of Technology ; Farahi, Gholamhossein (Supervisor)
Abstract
One of the most important issues in welding is residual stresses. It is desirable to produce less residual stresses when possible and to reduce them which remain in the structure. At the present, various methods have been developed to reduce the residual stresses. The most important methods are heat treatment, shot peening, and grinding. The main problem in using these methods is cost, and for large structures these methods are often impractical. In recent decades, a technique called vibratory stress relief has been developed. It is used for large structures without limitation of size and weight; besides, the cost of this process is much less in comparison with other conventional methods...
, M.Sc. Thesis Sharif University of Technology ; Nasiri Kenari, Masoumeh (Supervisor)
Abstract
In the recent years, the cooperative communications based on Network Coding have received significant attentions to simultaneously improve the diversity order and the network throughput. In this thesis, a new cooperative transmission scheme for the cooperative relay-based networks called “Convolutional Network-Coded Cooperation” (CNCC) is proposed, in which a systematic convolutional code is used in the network level. In this scheme, the systematic packets are directly transmitted by the sources, and the parity packets, calculated based on the received sources’ packets, are transmitted by the relays. The proposed CNCC scheme is considered in the cooperative networks including N sources, M...
Analysis of a two Echelon Queueing-Service System by Considering Speed-Quality Tradeoff in Service
, M.Sc. Thesis Sharif University of Technology ; Haji, Alireza (Supervisor)
Abstract
In this paper we study a two-echelon system including a vendor and a serviceprovider in customer-intensive services which introduced by Anand et al. (2011). Customers wish for high quality of service, which leads to longer service time for the service-provider. In the other hand, longer service times can cause to longer waiting time which is not desired for customers. So, tradeoff between service rate and quality of service/or product is critical. The market demand is according to Poisson process. The vendor will immediately send the order to the service-provider which works as a M/M/1 production system. The transportation time between the service-provider and vendor controlled by the...
Determination of Wake Effect of Stern on Performance of Marine Propeller with Self Propulsion Model Test
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad Saeed (Supervisor)
Abstract
According to the increasing need of the world to increase the speed of existing technologies such as computers, cars, urban transport, etc. The need to carry goods at higher speeds is also a concern that due to its cost It can make a significant contribution to the economy. In the maritime industries, in addition to the commercial and economic orientation, there is also military capability the speed factor and the ability to navigate is very important for military vessels. The power in the sea is inevitably dependent to speed, so for Increasing the speed of vessels with regard to military and economic objectives needs optimized Propulsion systems which There are also limitations for them....
A Five-Component Reaction for the Synthesis of New Benzylidenemalononitrile Derivatives Using Ultrasound Irradiation
, M.Sc. Thesis Sharif University of Technology ; Matloubi Moghaddam, Firouz (Supervisor)
Abstract
Nowadays, using one-pot multicomponent reactions in the synthesis of organic and natural compounds has attracted a lot of attention due to their ideal synthetic features. These types of reactions play an important role in synthetic chemistry by reducing reaction steps, costs, wastes, and by-products and increasing the reaction efficiency as an efficient method. The issue that led to this project was the development of a novel procedure for developing synthetic methods for the synthesis of thioxo-pyrrolidine 3-carbutamide compounds. In this study, the first Mumm rearrangement was performed by using dithiocarbamates by applying ultrasonic irradiation. The reaction was investigated in methanol...
Fabrication of Thin Layers Semiconductor Based on CTS
, M.Sc. Thesis Sharif University of Technology ; Mahdavi, Mohammad (Supervisor)
Abstract
Copper-based semiconductors have received a great deal of attention due to their high absorption coefficient, direct and adjustable energy gap with stoichiometry, low frequency and toxicity. Multicomponent nanocrystals such as CuInS2, Cu (In, Ga) (S, Se) 2, Cu2ZnSnS4 and Cu2SnS3 (CTS) have been successfully synthesized by colloidal synthesis and have shown application potentials such as energy conversion, photocatalyst, thermoelectric and biomedical. Among these, the CTS ternary semiconductor with p-type conduction is one of the most well-known compounds of group I-IV-VI, which consists of abundant and non-toxic elements. In this research, thin-film solar cells with FTO / TiO2 / In2S3 / CdS...
Effect of microstructure on crack behavior in nanocrystalline nickel using molecular dynamics simulation
, Article Theoretical and Applied Fracture Mechanics ; Volume 104 , 2019 ; 01678442 (ISSN) ; Farrahi, G. H ; Chamani, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
The crack growth process in columnar nanocrystalline samples is simulated using the molecular dynamics method. The effects of grain size, grain boundary, crystallographic orientation and crack tip position on the crack growth behavior are investigated. Different sets of samples with mean grain sizes ranging from 4 nm to 14 nm are prepared. Samples with a similar number of grains and identical dimensions are considered for examining the impact of grain boundary and crystallographic orientation. To assess the effect of the grain boundary, no constraint is considered on the position and orientation of grains, while only the grain orientations are changed to examine the effect of...
Feasibility Study for the Prediction of Earth Dam Behavior Using Combined Methodology of Deep Learning and Remote Sensing
, M.Sc. Thesis Sharif University of Technology ; Sadeghi, Hamed (Supervisor)
Abstract
Earth dams are among the most important and widely used civil structures, playing a significant role in water supply, energy production, and flood control. Monitoring dam behavior provides professionals with insights into its performance over time. Dam displacement is a crucial factor in deformation and potential failure, making it essential to use various measurement tools to control deformation and numerous simulation models to analyze data and monitor the dam continuously. However, it is not always possible to record data regularly and without disturbance, and some dams may lack these measurement tools altogether. In such cases, new technologies like remote sensing can significantly aid...
Molecular dynamics simulation of nanoindentation of nanocrystalline Al/Ni multilayers
, Article Computational Materials Science ; Volume 112 , 2016 , Pages 175-184 ; 09270256 (ISSN) ; Farrahi, G. H ; Movahhedy, M. R ; Sharif University of Technology
Elsevier
2016
Abstract
Molecular dynamics simulations are employed to investigate material properties of nanocrystalline aluminum and nanocrystalline Al/Ni multilayers at low temperature. For this purpose, both single crystal and nanocrystalline multilayers with different grain sizes and grain morphology are used as the substrate. The results of the simulations show that hardness and elastic modulus decrease with refinement of grain size in nanocrystalline aluminum and refinement of grain size and layer thickness in nanocrystalline Al/Ni multilayers, regardless of grain morphology. Furthermore, the angle between two adjacent grains, which is directly connected to the grain boundary thickness, has a great influence...
Friction behavior of nanocrystalline nickel near the Hall-Petch breakdown
, Article Tribology International ; Volume 107 , Volume 107 , 2017 , Pages 18-24 ; 0301679X (ISSN) ; Farrahi, G. H ; Movahhedy, M. R ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Large-scale molecular dynamics simulations are carried out to investigate the friction behavior of nanocrystalline nickel (Ni) at low temperature. Grain sizes ranging from 4–11 nm are used to explore the behavior of nanocrystalline Ni near the Hall-Petch breakdown. Effects of grain size, grain morphology and scratch depth on coefficient of friction (COF) and deformation mechanism of nanocrystalline Ni are investigated. Reduction of the COF with the refinement of grain size in nanocrystalline nickel is observed, however, for a grain size of 5 nm this trend is observed to be reversed. It is also found that scratch depth can influence the estimation of friction behavior of nanocrystalline...
A fuzzy random minimum cost network flow programming problem [electronic resource]
, Article Journal of Industrial and Systems Engineering (JISE)-Iranian Institute of Industrial Engineering ; Article 3, Volume 6, Issue 1, Spring 2012, Page 34-47 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, a fuzzy random minimum cost flow problem is presented. In this problem, cost parameters and decision variables are fuzzy random variables and fuzzy numbers respectively. The object of the problem is to find optimal flows of a capacitated network. Then, two algorithms are developed to solve the problem based on Er-expected value of fuzzy random variables and chance-constrained programming. Furthermore, the results of two algorithms will be compared. An illustrative example is also provided to clarify the concept
Special classes of mathematical programming models with fuzzy random variables [electronic resource]
, Article Journal of Intelligent and Fuzzy Systems, Published In: IOS Press ; Volume 19, Number 2, 2008 ; Nematian, Javad ; Sharif University of Technology
Abstract
In this paper, we will discuss two special classes of mathematical programming models with fuzzy random variables. In the first model, a linear programming problem with fuzzy decision variables and fuzzy random coefficients is introduced. Then an algorithm is developed to solve the model based on fuzzy optimization method and fuzzy ranking method. In the second model, a fuzzy random quadratic spanning tree problem is presented. Then the proposed problem is formulated and solved by using the scalar expected value of fuzzy random variables. Furthermore, illustrative numerical examples are also given to clarify the methods discussed in this paper
A special class of fuzzy integer programming model with all different constraints [electronic resource]
, Article Scientia Iranica ; Vol. 16, No. 1, pp. 1-10, 2009 ; Nematian, Javad ; Sharif University Of Technology
Abstract
In this paper, a fuzzy approach is applied to special classes of integer programming problems with all diierent constraints. In the rst model, a fuzzy integer programming model is developed to represent the all-diierent constraints in mathematical programming. In order to solve the proposed model, a new branching scheme for the Branch and Bound algorithm is also presented. In the second model, a special class of large-scale multi-objective fuzzy integer programming problems with all-diierent constraints is introduced. A solution method for the proposed model is also developed by using the decomposition technique, weighting method and Branch and Bound algorithm. An illustrative numerical...
Fuzzy random minimum cost network problem [electronic resource]
, Article Journal of Industrial and Systems Engineering ; Vol. 6, No. 1, pp 34-47, 2012 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, a fuzzy random minimum cost flow problem is presented. In this problem, cost parameters and decision variables are fuzzy random variables and fuzzy numbers respectively. The object of the problem is to find optimal flows of a capacitated network. Then, two algorithms are developed to solve the problem based on Er-expected value of fuzzy random variables and chance-constrained programming. Furthermore, the results of two algorithms will be compared. An illustrative example is also provided to clarify the concept
Effect of residual stress on failure of tube-to-tubesheet weld in heat exchangers
, Article International Journal of Engineering, Transactions A: Basics ; Volume 32, Issue 1 , 2019 , Pages 112-120 ; 17281431 (ISSN) ; Minaii, K ; Chamani, M ; Mahmoudi, A. H ; Sharif University of Technology
Materials and Energy Research Center
2019
Abstract
In a shell and tube heat exchanger, the failure of tube-to-tubesheet welds results in high-pressure water jet which erodes the refractory in front of the tubesheet. Finite element method was employed to simulate the welding process and post weld heat treatment (PWHT) to find the factors affecting the failure in tube-to-tubesheet weldments. Residual stresses in two different geometries of tube-to-tubesheet weldment were calculated through uncoupled thermal-structural analysis. The results showed that the values of residual stresses are higher in heat exchanger of site 1 than site 2 due to more weld passes and geometry of connection. Also, the maximum stress in site 1 occurs at the shellside...
A new Mumm-type rearrangement with dithiocarbamates via isocyanide-based multicomponent reaction under ultrasound irradiation: synthesis of polysubstituted pyrrolidine compounds
, Article New Journal of Chemistry ; Volume 44, Issue 23 , May , 2020 , Pages 9699-9702 ; Goudarzi, M ; Chamani, F ; Mohammadzadeh Dezag, H ; Sharif University of Technology
Royal Society of Chemistry
2020
Abstract
A novel and efficient multicomponent reaction for the synthesis of polysubstituted pyrrolidine derivatives is described under catalyst-free conditions using ultrasonic irradiation. The reactions were performed via a one-pot four-component condensation of secondary amines, carbon disulfide, isocyanides, and gem-dicyano olefins at room temperature to afford polysubstituted pyrrolidines diastereoselectively in 56-96% yields. This is the first report of a Mumm-type rearrangement with dithiocarbamates followed by intramolecular cyclization, which leads to the preparation of the key structure of pyrrolidine. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche...
Effect of residual stress on failure of tube-to-tubesheet weld in heat exchangers
, Article International Journal of Engineering, Transactions A: Basics ; Volume 32, Issue 1 , 2019 , Pages 112-120 ; 17281431 (ISSN) ; Minaii, K ; Chamani, M ; Mahmoudi, A. H ; Sharif University of Technology
Materials and Energy Research Center
2019
Abstract
In a shell and tube heat exchanger, the failure of tube-to-tubesheet welds results in high-pressure water jet which erodes the refractory in front of the tubesheet. Finite element method was employed to simulate the welding process and post weld heat treatment (PWHT) to find the factors affecting the failure in tube-to-tubesheet weldments. Residual stresses in two different geometries of tube-to-tubesheet weldment were calculated through uncoupled thermal-structural analysis. The results showed that the values of residual stresses are higher in heat exchanger of site 1 than site 2 due to more weld passes and geometry of connection. Also, the maximum stress in site 1 occurs at the shellside...