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Joint distributed source and network coding for multiple wireless unicast sessions
, Article 2009 IEEE Wireless Communications and Networking Conference, WCNC 2009, Budapest, 5 April 2009 through 8 April 2009 ; 2009 ; 15253511 (ISSN); 9781424429486 (ISBN) ; Movaghar, A ; Sharif University of Technology
2009
Abstract
Few works has been focused on the problem of joint distributed data compression and network coding. In this paper we give some examples showing the advantage of broadcast nature of wireless environment as a basis for joint codes design. Also we show that joint coding is possible in the case of multiple unicasts. The idea of this paper can be exploited in an opportunistic manner. Actually, the foundation of our idea is nothing but combining opportunistic network coding (COPE) and distributed source coding using syndromes (DISCUS) for wireless applications. © 2009 IEEE
Joint Disrtibuted Source and Network Coding
, M.Sc. Thesis Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor)
Abstract
Network coding, as a novel technique, suggests that the intermediate nodes of a network can combine independent flows to optimize the usage of a shared communication channel. Also, distributed source coding, exploits the joint statistics of correlated information sources to reduce the volume of transmitted information. Surprisingly, it has been shown that linear network codes are able to compress correlated sources. In this project, we have focused on this problem, i.e. joint distributed source and network coding. We have two important contributions with different directions. First we give a practical design for joint coding. Second, we use an evolutionary approach to find the best placement...
An evolutionary approach to generalized mirror sites problem
, Article 1st International Conference on Bio-Inspired Computational Methods Used for Solving Difficult Problems-Development of Intelligent and Complex Systems, BICS 2008, Tirgu Mures, 5 November 2008 through 7 November 2008 ; Volume 1117 , 2009 , Pages 40-46 ; 0094243X (ISSN); 9780735406544 (ISBN) ; Movaghar, A ; Beigy, H ; Petru Maior University; Romanian Academy ; Sharif University of Technology
2009
Abstract
The minimum cost subgraph for joint distributed source and network coding has been studied using a linear programming approach. This problem considers some statistically correlated information sources in a network, where sending over each link has a defined cost. The desired solution to this problem is a set of coding rates over the graph links, that minimizes the total communication costs. But in this problem, the placement of the sources is pre-defined, which is not necessarily optimal. In this paper, for the first time, we find a "good" placement for the sources using a genetic programming approach. This problem can be seen as the generalized mirror sites problem, where sources are not...
A comprehensive study on the fabrication and properties of biocomposites of poly(lactic acid)/ceramics for bone tissue engineering
, Article Materials Science and Engineering C ; Volume 70 , 2017 , Pages 897-912 ; 09284931 (ISSN) ; Hajiali, F ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
The fabrication of a suitable scaffold material is one of the major challenges for bone tissue engineering. Poly(lactic acid) (PLA) is one of the most favorable matrix materials in bone tissue engineering owing to its biocompatibility and biodegradability. However, PLA suffers from some shortcomings including low degradation rate, low cell adhesion caused by its hydrophobic property, and inflammatory reactions in vivo due to its degradation product, lactic acid. Therefore, the incorporation of bioactive reinforcements is considered as a powerful method to improve the properties of PLA. This review presents a comprehensive study on recent advances in the synthesis of PLA-based biocomposites...
Design, synthesis and application of imidazole-based organic dyes in dye sensitized solar cells
, Article Journal of Electronic Materials ; Volume 49, Issue 6 , 2020 , Pages 3735-3750 ; Alinezhad, H ; Hosseinzadeh, B ; Ghahary, R ; Tajbakhsh, M ; Sharif University of Technology
Springer
2020
Abstract
Metal-free D–D–π–A type dyes (i.e., Car-Cy, Car-Rh, Dpa-Cy, and Dpa-Rh) were designed and synthesized for dye-sensitized solar cells (DSSCs). In the structure of the sensitized dyes, an imidazole ring is connected to a carbazole or diphenylamine moiety as a donor while cyanoacetic acid or rhodanine-3-acetic acid was introduced as an acceptor/anchor. The molecular structures of D–D–π–A type dyes were characterized using IR, NMR and MS spectral data. The optical, electrochemical, theoretical, light harvesting property, HOMO/LUMO levels, redox behavior, and photovoltaic properties of the synthesized dyes were evaluated. Among the fabricated photovoltaic devices based on the prepared dye, Dpa-Cy...
A hybrid PSO-SA algorithm for the travelling tournament problem
, Article European Journal of Industrial Engineering ; Volume 6, Issue 1 , 2012 , Pages 2-25 ; 17515254 (ISSN) ; Eshghi, K ; Shamsi, A ; Sharif University of Technology
2012
Abstract
Sports scheduling has become an important area of applied operations research in recent years, since satisfying fans and teams' requests and revenues of a sports league and TV networks may be affected by quality of the league schedule. While this type of scheduling problem can be solved by mathematical methods and exact solutions are accessible, it computationally leads to hard problems. The travelling tournament problem (TTP) is defined as minimising total travelling distance for all teams in a league. In this study, a new mathematical model for the TTP with the no-repeater constraint is presented. In addition, a very fast hybrid metaheuristic algorithm is proposed, which combines particle...
A Hybrid PSO-SA algorithm for the traveling tournament problem
, Article 2009 International Conference on Computers and Industrial Engineering, CIE 2009, 6 July 2009 through 9 July 2009, Troyes ; 2009 , Pages 512-518 ; 9781424441365 (ISBN) ; Eshghi, K ; Shamsi, A ; Sharif University of Technology
2009
Abstract
Sports scheduling has become an important area of applied operationsresearch in recent years, since satisfying the fans and teams' requests andrevenues of a sports league and TV networks may be affected by the quality ofthe league schedule. While this type of scheduling problem can be solvedtheoretically by mathematical methods, it computationally leads to hardproblems. The Traveling Tournament Problem (TTP) is defined as minimizing totaltraveling distance for all teams in the league. In this study, a newmathematical model for the TTP with no-repeater constraint is presented. Inaddition, a very fast hybrid metaheuristic algorithm is proposed, which combinesParticle Swarm Optimization (PSO)...
LPF-Defense: 3D adversarial defense based on frequency analysis
, Article PLoS ONE ; Volume 18, Issue 2 February , 2023 ; 19326203 (ISSN) ; Noorbakhsh, K ; Etemadi, A ; Kasaei, S ; Sharif University of Technology
Public Library of Science
2023
Abstract
The 3D point clouds are increasingly being used in various application including safety-critical fields. It has recently been demonstrated that deep neural networks can successfully process 3D point clouds. However, these deep networks can be misclassified via 3D adversarial attacks intentionality designed to perturb some point cloud's features. These misclassifications may be due to the network's overreliance on features with unnecessary information in training sets. As such, identifying the features used by deep classifiers and removing features with unnecessary information from the training data can improve network's robustness against adversarial attacks. In this paper, the LPF-Defense...
Program state coverage: A test coverage metric based on executed program states
, Article 26th IEEE International Conference on Software Analysis, Evolution, and Reengineering, SANER 2019, 24 February 2019 through 27 February 2019 ; 2019 , Pages 584-588 ; 9781728105918 (ISBN) ; Jalali, S ; Mahdieh, M ; Mirian Hosseinabadi, S. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In software testing, different metrics are proposed to predict and compare test suites effectiveness. In this regard, Mutation Score (MS) is one of most accurate metrics. However, calculating MS needs executing test suites many times and it is not commonly used in industry. On the other hand, Line Coverage (LC) is a widely used metric which is calculated by executing test suites only once, although it is not as accurate as MS in terms of predicting and comparing test suites effectiveness. In this paper, we propose a novel test coverage metric, called Program State Coverage (PSC), which improves the accuracy of LC. PSC works almost the same as LC and it can be calculated by executing test...
Improving the mechanical behavior of the adhesively bonded joints using RGO additive
, Article International Journal of Adhesion and Adhesives ; Volume 70 , 2016 , Pages 277-286 ; 01437496 (ISSN) ; Adib Nazari, S ; Faghidian, S. A ; Vakili Tahami, F ; Etemadi, S ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In this research, Araldite 2011 has been reinforced using different weight fractions of Reduced Graphene Oxide (RGO). Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analyses were conducted and it has been shown that introduction of the RGO greatly changes the film morphology of the neat adhesive. Uni-axial tests were carried out to obtain the mechanical characteristics of the adhesive-RGO composites. It has been observed that introducing 0.5 wt% RGO enhances the ultimate tensile strength of the composites by 30%. In addition, single lap joints using neat adhesive and adhesive-RGO composites were fabricated to...
Capacity bounds and detection schemes for data over voice
, Article IEEE Transactions on Vehicular Technology ; Volume 65, Issue 11 , 2016 , Pages 8964-8977 ; 00189545 (ISSN) ; Boloursaz, M ; Etemadi, S. M ; Behnia, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Cellular networks provide widespread and reliable voice communications among subscribers through mobile voice channels. These channels benefit from superior priority and higher availability compared with conventional cellular data communication services, such as General Packet Radio Service, Enhanced Data Rates for GSM Evolution, and High-Speed Downlink Packet Access. These properties are of major interest to applications that require transmitting small volumes of data urgently and reliably, such as an emergency call in vehicular applications. This encourages excessive research to make digital communication through voice channels feasible, leading to the emergence of Data over Voice (DoV)...
Simulation of viscoelastic fluid flows in expansion geometry using finite volume approach
, Article Chinese Journal of Polymer Science (English Edition) ; Volume 31, Issue 12 , November , 2013 , Pages 1599-1612 ; 02567679 (ISSN) ; Ahmad Ramazani, S. A ; Habib Etemadi, M ; Ehsan Shirzaei, S ; Sharif University of Technology
2013
Abstract
The simulation results on viscoelastic fluid flows i sudden expansion geometry with different expansion ratios are presented. Oldroyd-B, linear Phan-Thien-Tanner (L-PTT) and Finitely Extensible Nonlinear Elastic (FENE-P) based constitutive equations were applied in two-dimensional Cartesian coordinates. The governing equations in transient and fully developed regions were solved using open source software called OpenFOAM. The flow patterns, including velocity profiles, shear stresses and first normal stress differences in some horizontal and vertical sections are illustrated. In addition, effects of the fluid type, flow dynamics and expansion ratio on the flow and vortex patterns in...
Incorporating fault-proneness estimations into coverage-based test case prioritization methods
, Article Information and Software Technology ; Volume 121 , May , 2020 ; Mirian Hosseinabadi, S. H ; Etemadi, K ; Nosrati, A ; Jalali, S ; Sharif University of Technology
Elsevier B. V
2020
Abstract
Context: During the development process of a software program, regression testing is used to ensure that the correct behavior of the software is retained after updates to the source code. This regression testing becomes costly over time as the number of test cases increases and it makes sense to prioritize test cases in order to execute fault-detecting test cases as soon as possible. There are many coverage-based test case prioritization (TCP) methods that only use the code coverage data to prioritize test cases. By incorporating the fault-proneness estimations of code units into the coverage-based TCP methods, we can improve such techniques. Objective: In this paper, we aim to propose an...
Failure analysis of holding yokes made of investment cast 17-4 PH stainless steel
, Article Engineering Failure Analysis ; Volume 18, Issue 4 , 2011 , Pages 1242-1246 ; 13506307 (ISSN) ; Behjati, P ; Emami, A ; Motiei, S. M. A. D ; Mirsaeedi, S ; Sharif University of Technology
2011
Abstract
Holding yokes made of investment cast 17-4PH stainless steel were too soft (below 20. HRC). Optical microscopy of the parts showed that there is a high fraction of retained austenite after oil quench due to high amount of molybdenum found in parts as an impurity. Subzero treatment in liquid nitrogen after solution heat treating was used to convert retained austenite to martensite but parts became too brittle and fractured during post-heat treating machining. Double and triple aging at 538 °C (1000 °F) after subzero cooling was done on parts. Detailed fractography and tensile testing along with optical microscopy (OM) investigation proved that repeated aging at 538 °C (1000 °F) led to lower...
Probabilistic failure analysis of hot gas path in a heavy-duty gas turbine using Bayesian networks
, Article International Journal of Systems Assurance Engineering and Management ; Volume 10, Issue 5 , 2019 , Pages 1173-1185 ; 09756809 (ISSN) ; Adib Nazari, S ; Maghsoud Pour, A ; Etemadi Haghighi, S ; Zareh, M ; Sharif University of Technology
Springer
2019
Abstract
Heavy-duty gas turbines are usually devised in power plants to generate electrical energy. Sudden failure in any of its parts or subdivisions will result in a decrement of the efficiency of the system or emergency shutdown of the system. The highest risk of failure in these turbines is subjected to the hot gas path (HGP) of the turbine. Due to the existence of uncertainty in diagnosing process or damage growth, in this research, a modified risk-based probabilistic failure analysis model using Bayesian networks (BN) was developed. First, a failure model was developed using the Fault Tree Analysis, and then it is transformed into a BN model. This model is capable of predicting and diagnosing...
Failure analysis of first stage nozzle in a heavy-duty gas turbine
, Article Engineering Failure Analysis ; Volume 109 , January , 2020 ; Adib Nazari, S ; Maghsoud Pour, A ; Etemadi Haghighi, S ; Zareh, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
First stage nozzles are considered as one of the most critical components in the heavy-duty gas turbines because of their operational in-service condition in the hot gas path. In the present research, the failure analysis of a first stage nozzle in a 159 MW gas turbine is investigated in order to specify the modes and mechanisms of the failure and their root causes. Various examinations including macroscopic and visual inspection of the nozzle outer surface, the micro examination of the fracture surface, chemical analysis and metallographic analysis were carried out to complete the investigation. The micro and macro examinations revealed cracks, erosion and oxidation damages in the nozzle...
A lower capacity bound of secure end to end data transmission via GSM network
, Article 2012 6th International Symposium on Telecommunications, IST 2012, 6 November 2012 through 8 November 2012 ; Novembe , 2012 , Pages 1015-1020 ; 9781467320733 (ISBN) ; Mosayebi, R ; Etemadi, S. M ; Boloursaz, M ; Behnia, F ; Sharif University of Technology
2012
Abstract
Global System for Mobile communications (GSM) is a widely spread, reliable and P2P channel through all over the world. These characteristics make GSM a channel suitable for a variety of applications in different domains especially security applications such as secure voice communication. Performance and usage of GSM applications extremely depends on the transmission data rate. Hence, transmitting data over GSM is still an attractive topic for research. This paper considers the problem of digital data transmission through the GSM voice channel. A lower capacity bound for data transmission through the GSM Adaptive Multi Rate (AMR) voice codec is presented. The GSM channel is modeled in a...
Characterization of reinforcing effect of alumina nanoparticles on the novolac phenolic resin
, Article Polymer Composites ; Vol. 35, Issue 7 , July , 2014 , pp. 1285-1293 ; ISSN: 02728397 ; Shojaei, A ; Sharif University of Technology
2014
Abstract
Very fine alumina nanoparticles were loaded in novolac type phenolic resin (PF) using solution mixing method. The concentration of nanoalumina in PF was varied between 2.5 to 20 wt%. All the compounds were compression molded and then subjected to scanning electron microscopy (SEM), tensile, flexural, and dynamic mechanical analysis (DMA) tests. SEM analysis showed that the nanoalumina were dispersed uniformly at low concentrations, however, at high concentrations, dispersion was suppressed leading to agglomerates in the composites. Mechanical testing revealed that the nanoalumina had a great influence on the strength and stiffness of PF resin particularly at concentrations below 5 wt%....
Throughput analysis of IEEE 802.11-based vehicular ad hoc networks
, Article IET Communications ; Volume 5, Issue 14 , Sept , 2011 , Pages 1954-1963 ; 17518628 (ISSN) ; Ashtiani, F ; Sharif University of Technology
2011
Abstract
In this study, the authors propose an analytical model to evaluate the maximum stable throughput for unicast services in vehicular ad hoc networks. In this respect, the authors employ two queueing networks (QNs) to model the mobility patterns of the vehicles as well as the multi-hop packet transmission scenario. In the proposed model, the authors map the features of IEEE 802.11, as well as the details of multi-hop packet transmission, regarding the dynamic status of vehicles, onto suitable parameters of the QNs. In the authors' modelling approach, they take the details of MAC and routing schemes into account by classifying the vehicles based on their mobility patterns and considering their...
Simulation of Drag Reduction Via Microgrooves
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
Drag reduction on surfaces always has been a great case of study, especially in transport industry. This project discusses the external laminar flow of a single-phase fluid over a flat plate and the effects of making rectangular tiny grooves - in micron or millimeter - on them to reduce total drag. Making grooves with appropriate geometry on surfaces causes the fluid-solid contact area on the groove's surface turn into fluid-fluid and as a result the fluid will not shed into the groove. In other words the flow instead of having a no-slip boundary condition on inner surfaces of the groove, creates vortices in them that causes a remarkable reduction in velocity gradient followed by a skin...