Layered hybrid digital-analog coding with correlated interference

, Article IEEE International Conference on Communications ; 2012 , Pages 2565-2569 ; 15503607 (ISSN) ; 9781457720529 (ISBN) Varasteh, M ; Behroozi, H ; Sharif University of Technology

2012

Abstract

In this paper, we propose a modified joint source-channel coding (JSCC) scheme on the transmission of an analog Gaussian source over an additive white Gaussian noise (AWGN) channel in the presence of an interference, correlated with the source. This setting naturally generalizes the problem of sending a single Gaussian source over an AWGN channel, in the case of bandwidth-matched, and with uncorrelated interference in which separation-based scheme with Costa coding is optimal. We analyze the modifeied scheme to obtain achievable (mean-squared error) distortion-power tradeoff. For comparison, we also obtain a new outer bound for the achievable distortion-power tradeoff. Using numerical...

On the transmission of a Gaussian source over an AWGN channel with correlated interference

, Article 12th Canadian Workshop on Information Theory, CWIT 2011, 17 May 2011 through 20 May 2011 ; May , 2011 , Pages 19-23 ; 9781457707438 (ISBN) Varasteh, M ; Behroozi, H ; Sharif University of Technology

2011

Abstract

We study hybrid digital-analog (HDA) joint source-channel coding schemes in transmitting an analog Gaussian source over an AWGN channel in the presence of an interference, correlated with the source. We analyze these schemes to obtain achievable (mean-squared error) distortion-power tradeoffs. For comparison, we also obtain two outer bounds for the achievable distortion-power tradeoff; those are two necessary conditions under which (D,P) is achievable. Using numerical examples, we demonstrate that, a two-layered coding scheme consisting of analog and Costa coding performs well compared to other provided HDA schemes

Optimal HDA schemes for transmission of a Gaussian source over a Gaussian channel with bandwidth compression in the presence of an interference

, Article IEEE Transactions on Signal Processing ; Volume 60, Issue 4 , January , 2012 , Pages 2081-2085 ; 1053587X (ISSN) Varasteh, M ; Behroozi, H ; Sharif University of Technology

2012

Abstract

We consider transmission of a Gaussian source over a Gaussian channel under bandwidth compression in the presence of an interference known only to the transmitter. We study hybrid digital-analog (HDA) joint source-channel coding schemes and propose two novel layered coding schemes that achieve the optimal mean-squared error (MSE) distortion. This can be viewed as the extension of results by Wilson ["Joint Source Channel Coding With Side Information Using Hybrid Digital Analog Codes," IEEE Trans. Inf. Theory, vol. 56, no. 10, pp. 4922-2940, Oct. 2010], originally proposed for sending a Gaussian source over a Gaussian channel in two cases: 1) Matched bandwidth with known interference only at...

Optimal HDA codes for sending a Gaussian source over a Gaussian channel with bandwidth compression in the presence of an interference

, Article 2011 IEEE Information Theory Workshop, ITW 2011 ; 2011 , Pages 325-329 ; 9781457704376 (ISBN) Varasteh, M ; Behroozi, H ; Sharif University of Technology

2011

Abstract

In this paper, we consider transmission of a Gaussian source over a Gaussian channel under bandwidth compression in the presence of interference known only to the transmitter. We study hybrid digital-analog (HDA) joint source-channel coding schemes and propose two novel coding schemes that achieve the optimal mean-squared error (MSE) distortion. This can be viewed as the extension of results by Wilson et al. [1], originally proposed for sending a Gaussian source over a Gaussian channel in two cases: 1) Matched bandwidth with known interference only at the transmitter, 2) bandwidth compression where there is no interference in the channel. The proposed HDA codes can cancel the interference of...

Server consolidation techniques in virtualized data centers: a survey

, Article IEEE Systems Journal ; Volume 11, Issue 2 , 2017 , Pages 772-783 ; 19328184 (ISSN) Varasteh, A ; Goudarzi, M ; Sharif University of Technology

2017

Abstract

Data centers and their applications are exponentially growing. Consequently, their energy consumption and environmental impacts have also become increasingly more important. Virtualization technologies are widely used in modern data centers to ease the management of the data center and to reduce its energy consumption. Data centers that employ virtualization technologies are typically called virtualized or cloud data centers. Virtualization technologies enable virtual machine (VM) live migration, which allows the VMs to be freely moved among physical machines (PMs) with negligible downtime. Thus, several VMs can be packed on a single PM so as to let the PM run in its more energy-efficient...

Joint Source Channel Coding with Hybrid Digital Analog Codes in the Presence of Intereference

, M.Sc. Thesis Sharif University of Technology Varasteh, Morteza (Author) ; Behroozi, Hamid (Supervisor)

Abstract

In this thesis we consider transmitting an analog Gaussian source over an AWGN channel in the presence of an interference completely known at the transmitter intwo cases: 1) Compression bandwidth with interference uncorrelated with the sourceand 2) Matched bandwidth channel in the presence of interference correlated withthe source to be transmitted. We study joint source-channel coding schemes basedon hybrid digital-analog (HDA) codes. After providng a brief review, we will proposetwo new schemes for the ?rst case and one novel scheme for the second case. Aswe will see both schemes for the ?rst case achieve the optimal mean-squared error(MSE) distortion. The proposed HDA schemes can...

Regionalized Lifetime-aware Virtual Machine Consolidation Algorithm for Cloud Datacenters

, M.Sc. Thesis Sharif University of Technology Varasteh Hajipour, Amir (Author) ; Goudarzi, Maziar (Supervisor)

Abstract

In the past few years, data centers energy consumption and their maintenance costs have become an important issue in technology world. Server consolidation using virtualization and VM live migration allows cloud data centers to improve resource utilization and hence energy efficiency. In order to save energy, consolidation techniques try to turn off the idle servers, while because of workload fluctuations, these offline servers should be turned on to support the increased resource demands. These repeated on-off cycles could affect the hardware reliability and wear-and-tear of servers and increase the maintenance and replacement costs. On the other hand, over-aggressive strategies would...

The fracture behavior of rubbery vulcanizates: I. Single component versus blend systems

, Article Rubber Chemistry and Technology ; Volume 75, Issue 1 , 2002 , Pages 77-82 ; 00359475 (ISSN) Taheri Qazvini, N ; Mohammadi, N ; Jalali, A ; Varasteh, A ; Bagheri, R ; Sharif University of Technology

Rubber Division of the American Chemical Society 2002

Abstract

The tear energy and heat build up of NR, SBR and BR vulcanizates and their corresponding blends were measured at several temperatures via modified trouser tear and Goodrich flexometer experiments. In all single component samples, by increasing temperature from -10 to 125°C, the fracture energy decreases, goes through a minimum and increases again. Nevertheless, in SBR and BR, a level off and a level off followed by second drop occur at higher temperatures, respectively. On the other hand, for aforementioned samples the heat build up decreases monotonically by raising the temperature. For two-component blends, the fracture energy and heat build up show different dependencies on temperature in...

Ant colony algorithm for the shortest loop design problem [electronic resource]

, Article Computers and Industrial Engineering, Elsevier ; Volume 50, Issue 4, August 2006, Pages 358–366 Eshghi, K. (Kourosh) ; Kazemi, Morteza ; Sharif University of Technology

Abstract

In this paper, a new algorithm for solving the shortest loop design problem is presented. The shortest loop design problem is to find the shortest loop for an automated guided vehicle covering at least one edge of each department of a block layout. In this paper, first it is shown that this problem can be represented as a graph model. The properties of the presented model enable us to design a meta-heuristic based on ant colony system algorithm for solving the shortest loop design problem. Computational results show the efficiency of our algorithm in compare to the other techniques

Modeling Reaction and Distribution of Water in Nanopores of the Cathode Catalyst Layer of PEM Fuel Cell

, M.Sc. Thesis Sharif University of Technology Nushak, Fatemeh (Author) ; baghalha, morteza (Supervisor)

Abstract

In the proton exchange membrane fuel cells (PEM, the produced water would be divided into two phases of vapor and liquid. distribution of both liquid and vapor phases in different cell layers affects the performance, the efficiency and the life of a fuel cell significantly. Moreover, Nano pores of the cathode catalyst layer are involved with some phenomena such as electrochemical reaction kinetics, heat and mass transfer and interface phase change. One of the most important problems in the performance of fuel cells is distribution of liquid water in the porous areas. Water flooding in fuel cells causes to delay in oxygen transport to active sites in the catalyst layer because the pores of...

Love Wave Propagation in a Functionally Graded Magneto-Electro-Elastic Half-Space with Quadratic Variations

, M.Sc. Thesis Sharif University of Technology Nobahar, Masoud (Author) ; Eskandari, Morteza (Supervisor)

Abstract

The propagation behavior of Love wave in functionally graded magneto-electro-elastic half-spaces with a quadratic variation is addressed. The magneto-electromechanical coupling factor, the dispersion relations, electric potential, magnetic potential and displacement are obtained analytically for both magneto-electrically open and short conditions. The effect of gradient coefficient on phase velocity, group velocity and magneto-electromechanical coupling factor are plotted and discussed. Research on the wave propagation in magneto-electro-elastic materials is still very limited. This work provides us with a theoretical foundation to design and practically apply SAW devices with high...

Elastic Analysis of a Surface Stiffened Transversely Isotropic Half-space Under a Buried Horizontal Point Load

, M.Sc. Thesis Sharif University of Technology Naghib, Hamed (Author) ; Eskandari, Morteza (Supervisor)

Abstract

In this study, the interaction between thin plate completely bonded to the transversely isotropic halfspace and a concentrated force applied horizontally (Mindlin-type force) are considered. This problem has been solved analytically. This problem is used as sample for thin solid films and surface coating technology, where the surface of solid is covered by thethin plate for increasing its stiffness. Moreover, this problem is a good sample when homogenous solid is subjected to contact loading and can be seen that mechanical properties of material which is near the solid surface varies; consequently, a two-phase solid is created.Because of the influence of noted inhomogeneity, solid is...

Modeling and Simulation of the Catalyst Regeneration Process of FCC Unit of Abadan Refinery

, M.Sc. Thesis Sharif University of Technology Loni, Zahra (Author) ; Baghalha, Morteza (Supervisor)

Abstract

Hydrodynamics plays a crucial role in defining the performance of fluidized beds. The numerical simulation of fluidized bed is very important in the prediction of its behaviour. From this point of view, in the present study a dynamic two dimensioanl model is developed for the modeling of regenerator system of a UOP fluid catalytic cracking (FCC) unit of Abadan refinery with a high-efficiency regenerator. Of the various modeling and simulation techniques, computational fluid dynamics (CFD) is employed in this thesis. Effects of gas velocity, the transient local solid volume fraction, pressure drop for gas and solid phase, solid holdup distribution and solid circulation pattern have been...

Secure- multiparty Computation Protocol for Privacy Preserving Data Mining

, M.Sc. Thesis Sharif University of Technology Maftouni, Mahya (Author) ; Amini, Morteza (Supervisor)

Abstract

Privacy preserving data mining helps organizations and companies not only to deal with privacy concerns of customers and regular limitations, but also to benefit from collaborative data mining. Utilizing cryptographic techniques and secure multiparty computation (SMC) are among widely employed approaches for preserving privacy in distributed data mining. The general purpose of secure multiparty computation protocols to compute specific functions on private inputs of parties in a collaborative manner and without revealing their private inputs. Providing rigorous security proof of secure multiparty computation makes it a good choice for privacy preservation, despite of its cryptographic...

Information-flow Analysis in Android Apps for Protecting User Privacy

, M.Sc. Thesis Sharif University of Technology Barkhordari, Alireza (Author) ; Amini, Morteza (Supervisor)

Abstract

The rapid growth of Android operating system alongside its open-source nature has made it as the most popular operating system of mobile devices. On the other hand, regarding the increasing computational power of mobile devices, a wide variety of applications are coming to this type of devices. Meanwhile unfortunately many malicious softwares trying to keep up with other applications, are targeting this popular operating system. Therefore with regard to the fact that this type of devices usually store private and sensitive information of their users, security of mobile operating systems is considered very important. Having this matter in mind, the goal of this research work has been...

Analysis of Slabs Stiffened by Cables and Pedestals

, M.Sc. Thesis Sharif University of Technology Mokhberi, Arsalan (Author) ; Eskandari, Morteza (Supervisor)

Abstract

In this study, a new concrete slab stiffened by concrete pedestals and steel cables is introduced. The slab system is studied by employing both analytical and numerical methods. The steel cables are connected to the edges of slab and the concrete pedestals mounted at the bottom face of slab act as the middle supports of cables. The tension force in the cable and its inclination results in upward forces acting at the bottom face of slab. With the aims of classical theory of thin plates and the superposition technique, the problem of a simply supported rectangular slab stiffened by cables is studied analytically. The obtained results are verified by a numerical modelling implemented in SAP2000...

Parametric Study of Telescopic Metallic Yielding Dampers

, M.Sc. Thesis Sharif University of Technology Misaghi, Mohammad (Author) ; Eskandari, Morteza (Supervisor)

Abstract

The parametric study of a new introduced metallic yielding damper called telescopic damper is addressed. The telescopic damper comprises of three concentric steel pipes connected together by lead shear keys. The inner and outer steel pipes are subjected to axial loading which results in the shear yielding of the embedded lead cylinders. The inner steel pipe has a lock which limits its movement to some certain extent and beyond this limit the outer tube activates. Employing ABAQUS software, the behavior of damper under cyclic loading is studied numerically. The finite element model is verified by available results in the literature. The effects of inner and outer steel pipes thickness,...

An Access Control System for Time Series Data in NoSQL Databases

, M.Sc. Thesis Sharif University of Technology Noury, Amir (Author) ; Amini, Morteza (Supervisor)

Abstract

An important class of applications which have been rapidly growing recently is the one that create and use time series data. These types of data sets are ordered based on the timestamps associated to their data items. In practice, traditional relational databases are unable to satisfy the requirements of these data sets; however, NoSQL databases with column-wide data structure are appropriate infrastructure for them. These databases are very efficient in read and write operations (especially for time series data, which are ordered) and are able to store unstructured data. Time series data may contain valuable and sensitive information; hence, they should be protected from the information...

Database Schema Extraction Prevention Through DBMS Error Handling

, M.Sc. Thesis Sharif University of Technology Naghdi, Sepideh (Author) ; Amini, Morteza (Supervisor)

Abstract

Nowadays large volume of sensitive data of organizations are stored in the databases. Thus, databases are attractive to the attackers to execute different types of attacks with different purposes. The useful information that attackers try to achieve in the preliminary steps of the attacks against the databases, is the database structure or schema. One of the popular approach to extract the schema of a database is to analyze the returned error messages from its DBMS. Hence, a solution to prevent schema disclosure via the error messages is customizing and modifying them. To achieve this goal, in this thesis, we propose a framework to handle and customize the error messages automatically and...

Numerical Simulation of a Telescopic Metallic Yielding Damper

, M.Sc. Thesis Sharif University of Technology Davoodi, Vahid (Author) ; Eskandari, Morteza (Supervisor)

Abstract

In this study, a new type of metallic yielding damper called Telescopic damper is proposed and analyzed numerically. The damper comprises of three concentric steel tubes connected together by lead shear keys. The relative axial deformation of steel tubes under axial forces results in shear deformation and yielding in lead shear keys and dissipates energy. The inner steel tube has a lock which limits its movement to some certain extent and beyond this limit the outer tube activates. Therefore, a multi-linear force-deformation behavior with two different yield plateaus is expected for the introduced telescopic damper. The multi-level yield plateaus of damper makes it effective in both low and...