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A fast and reliable multi-sender algorithm for peer-to-peer networks
, Article Journal of Network and Computer Applications ; Volume 32, Issue 3 , May , 2009 , Pages 733–740 ; Sharif University of Technology
2009
Abstract
Due to special constraints in peer-to-peer (P2P) networks (such as bandwidth limitation) and because of their highly dynamic characteristics, a single node cannot provide a reliable multimedia stream to the receivers. Several multi-sender algorithms are proposed to reliably deliver a media stream to the receiver through the intrinsically unreliable P2P networks. Based on upload bandwidths and availability of peers as well as the bandwidths of the links connecting the senders and the receiver, PROMISE selects a set of active senders to maximize the expected bit-rate delivered to the receiver. By careful investigation of PROMISE, in this paper, we present why and how it deviates from finding...
A multi-sender multicast algorithm for media streaming on peer-to-peer networks
, Article Computer Communications ; Volume 30, Issue 10 , July , 2007 , Pages 2191-2200 ; Ronasi, K. (Keivan) ; Pakravan, M. R. (Mohammad Reza) ; Nasiri Avanaki, A. (Alireza) ; Sharif University of Technology
2007
Abstract
Unlike those on Internet, the media providers on P2P networks are ordinary nodes with limited shared resources such as bandwidth. Multi-sender methods are the best existing solutions to video streaming on P2P networks. In this paper, we propose use of a multicast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. Experimental results, derived from implementation of the proposed algorithm on Pastry P2P network confirm our claim. Another advantage of our method over the existing methods is its scalability with the number of receivers
Identification of external power system linear dynamic equivalents as MIMO feedback blocks for the study system
, Article International Journal of Emerging Electric Power Systems ; Volume 8, Issue 5 , 21 Nov. 2007 , 2007 ; 1553779X (ISSN) ; Ranjbar, A. M ; Lesani, H ; Radmanesh, H ; Sharif University of Technology
2007
Abstract
The necessity of dynamic equivalents for power system analysis has been well known since the expansion of large interconnected power networks, and has been discussed during the last decades. The present paper proposes a new method for constructing dynamic equivalents of power systems. In this method, at the first step the "study system" is modeled completely via a single machineinfinite bus modeling procedure. Then the "external system" is identified as a MIMO feedback block of this model in such a manner that can include dynamic effects of the latter on the behavior of the former. The method is successfully experimented on a part of the Iranian southern network. Copyright © 2007 The...
An efficient tabu search algorithm for the single row facility location problem [electronic resource]
, Article European Journal Of Operational Research ; Vol. 205, No. 1, pp. 98-105 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
The general goal of the facility layout problem is to arrange a given number of facilities to minimize the total cost associated with the known or projected interactions between them. One of the special classes of the facility layout problem is the Single Row Facility Layout Problem (SRFLP), which consists of finding an optimal linear placement of rectangular facilities with varying dimensions on a straight line. This paper first presents and proves a theorem to find the optimal solution of a special case of SRFLP. The results obtained by this theorem prove to be very useful in reducing the computational efforts when a new algorithm based on tabu search for the SRFLP is proposed in this...
Sensitivity analysis of matching pennies game [electronic resource]
, Article Mathematical and Computer Modelling ; Volume 51, Issues 5–6, March 2010, Pages 722–735 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, we have discussed the results of sensitivity analysis in a payoff matrix of the Matching Pennies game. After representing the game as a LP model, the sensitivity analysis of the elements of the payoff matrix is presented. The game value and the optimal strategies for different values of parameters are determined and compared
Separation of delamination modes in composite beams with symmetric delaminations
, Article Materials and Design ; Volume 27, Issue 10 , 2006 , Pages 900-910 ; 02613069 (ISSN) ; Nosier, A ; Farrahi, G. H ; Sharif University of Technology
Elsevier Ltd
2006
Abstract
Delaminated composite beam under general edge loading conditions is studied. Based on a technical engineering theory an analytical procedure for calculation of strain energy release rate and its separation into modes I and II of delamination is presented. By choosing a suitable displacement field based on second-order shear-thickness deformation theory and using the principle of minimum total potential energy, the equations of equilibrium are obtained along with the appropriate boundary conditions. The J integral and its definition for different modes of fracture is used for calculation of strain energy release rate and its separation into different modes. Double cantilever beam (DCB)...
Forced Vibration of Drill String and its Control in Directional Drilling
, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed (Supervisor)
Abstract
Nowadays, economical extraction of oil and gas, and their products is an important issue for many countries. Up to now, vertical wells have been used for oil extraction but some wells exist that they cannot be reached by using vertical drilling; for example the wells under a sea. Therefore, this makes the governments and scientists determined to find a new way to reach them. Horizontal drilling is one of the new ways to reach such worthy wells. In this project, dynamics of the horizontal drill string is studied. Then, according to the forces that affect the dynamics of drilling, its vibration is analyzed. After finding the boundary conditions and normal modes of the system with using mode...
Evaluation of Hollowfiber Membranes Uesd In Hemodialysis
, M.Sc. Thesis Sharif University of Technology ; Abdekhodaei, Mohammad Jafar (Supervisor)
Abstract
Due to largre number of patients treated by dialysis and its significant increasing progress, dialysis efficiency and patients' life quality are of great interest.Dialyzer, the dialysis beating heart, has the role of cleaning blood by removing toxic solutes and balancing volume of bood's water through hollow fiber membranes. In this thesis, firstly we tried to focus on performance characteristics of dialyzer by studying effective parameters influencing dialyzer efficiency and ultimately we set two important performance characteristics, ultrafiltration coefficient and solute clearance, as our goal parameters for evaluating dialyzer's yield. To this purpose, we designed an experimental set...
Optimal Control of Multi-Zone Air Conditioning System to Achieve Thermal Comfort and Minimize Energy Consumption
, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed (Supervisor)
Abstract
Air conditioning systems are one of the main parts of buildings, and their performance is very important, especially during the peak heat and cold days, both in terms of providing comfort area for the people and in terms of energy consumption. These systems control the temperature and humidity inside one or more target zones using heating, cooling, humidification, and dehumidification processes. One of the most common solutions to optimize the performance of air conditioning systems is the use of control systems. In this study, a nonlinear multi input-multi output dynamic model of a two-zone variable air volume & temperature air handling unit is considered for operation in the summer season....
Combination of Two-Stage Optimized Active Control of Edgewise vibrations of Wind Turbine Blades by using Robotic Arms
, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed (Supervisor)
Abstract
Renewable energies and their various types have been recognized as sustainable solutions to address the challenges arising from increasing energy consumption and environmental issues. The use of wind energy as one of the renewable energy sources has particular advantages, considering it as one of the most sustainable energy sources. One of the key factors in wind turbine development is the diversity and multiplicity in their structural designs. Therefore, the design of wind turbine structures with characteristics such as suitable strength, high energy efficiency, optimal cost, and high reliability is of great importance. By employing various sciences such as vibrations and optimization in...
Study on the dynamic and static softening phenomena in Al-6Mg alloy during two-stage deformation through interrupted hot compression test
, Article Measurement: Journal of the International Measurement Confederation ; Volume 77 , 2016 , Pages 50-53 ; 02632241 (ISSN) ; Pakbaz, M ; Firooz, S ; Jandaghi, M. R ; Khalaj, G ; Sharif University of Technology
Elsevier, B. V
2016
Abstract
The dynamic and static softening phenomena in Al-6Mg alloy were studied through interrupted two-stage hot compression test performed isothermally at 480°C and strain rate range of 0.001-0.1 s-1. The interruptions of 29 and 90 s were considered when the true strain reached 0.5. It was concluded that the effect of static softening on the flow stress was not highlighted by extending the interruption at a constant strain rate. Also, it was exhibited that softening rate highly enhanced with the strain rate decrement at a constant time. Moreover, the static and dynamic recrystallization was revealed as the dominant softening mechanisms at low and high strain rates, respectively
Wavelet-based unbalanced un-equivalent multiple description coding for P2P networks
, Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 242-247 ; 1424410940 (ISBN); 9781424410941 (ISBN) ; Ronasi, K ; Pakravan, M. R ; Nasiri Avanaki, A ; Sharif University of Technology
2007
Abstract
Almost all existing multi-description coding (MDC) schemes are designed for media streaming over Internet. In this work, a wavelet-based video MDC technique is introduced that fits the criteria of media streaming over peer-to-peer networks. Our proposed method assigns descriptions to the senders due to their characteristic (i.e. bandwidth and availability). In contrast to traditional MDC, different descriptions in the proposed method have different importance in remaking the original media. Our simulation results show considerable improvement of video quality at the receiver (up to 10 dB) as compared to the state-of-the-art. ©2007 IEEE
IPROMISE: Reliable multi-sender algorithm for peer-to-peer networks
, Article 2007 2nd International Conference on Communication System Software and Middleware and Workshops, COMSWARE 2007, Bangalore, 7 January 2007 through 12 January 2007 ; 2007 ; 1424406145 (ISBN); 9781424406142 (ISBN) ; Ronasi, K ; Pakravan, M. R ; Nasiri Avanaki, A ; Sharif University of Technology
2007
Abstract
Due to the constraints of P2P networks (such as bandwidth limitation) multiple senders should be employed for reliable multimedia streaming. This paper introduces a mathematic approach to select a set of senders among all available senders to provide the most reliable stream for the receiver. This selection is based on upload bandwidths and availability of peers as well as bandwidth of links connecting the senders and the receiver. Our method is called IPROMISE as it is an improved version of the PROMISE algorithm. Simulation results demonstrate improved media quality delivered to the receiver, while the complexity of sender selection remains the same. © 2007 IEEE
A novel multi-sender algorithm based on multi-cast concept for P2P networks
, Article 2006 International Symposium on Communications and Information Technologies, ISCIT, Bangkok, 18 October 2006 through 20 October 2006 ; 2006 , Pages 143-147 ; Ronasi, K ; Pakravan, M. R ; Avanaki, A. N ; Sharif University of Technology
2006
Abstract
Unlike those on Internet, the media providers on P2P networks are ordinary nodes whose contribution bandwidth is limited. Multi-sender methods are the best solutions known to video streaming on P2P networks. In this paper, we propose use of a multi-cast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. That is while the existing multi-sender methods maximize the bit-rate delivered to the first receiver and cannot provide acceptable bit-rates to the next requesting nodes. © 2006 IEEE
Studying Short-Run and Long-Run Relationship between Real Exchange Rate and Real GDP in Iran
, M.Sc. Thesis Sharif University of Technology ; Nili, Masoud (Supervisor)
Abstract
Exchange rate is one of the macroeconomic variables that can affect domestic product, economic growth and unemployment. Since macroeconomics wants to explain inflation, unemployment and economic growth, exchange rate is one of the most important macroeconomic variables. In economic literature, many studies have been performed to investigate the linkage between Real Exchange Rate (RER) and other real economic variables (such as domestic product, unemployment, etc.). In this study, we first construct the RER for the economy of Iran and then, using Vector Error Correction Model (VECM), short-run and long-run relations between RER and Gross Domestic Product (GDP) is evaluated.
The results of...
The results of...
Quantifying the Social Impacts of Infrastructure Systems Failure for Community Resilience Analysis
, M.Sc. Thesis Sharif University of Technology ; Kashani, Hamed (Supervisor)
Abstract
The purpose of this study is to present a suitable model for calculating the costs imposed on society due to deaths and injuries due to infrastructure failure due to earthquakes, which is used in the analysis of community resilience. Much research has been done to date to calculate the economic costs of infrastructure failure. However, no suitable analytical framework has been provided to quantify the costs of deaths and injuries to people due to earthquake failure. Previous research has provided methods such as the value of statistical life to quantify the social costs caused by accidents and environmental pollution. However, the literature review results in the field of seismic resilience...
A fast and reliable multi-sender algorithm for peer-to-peer networks
, Article Journal of Network and Computer Applications ; Volume 32, Issue 3 , 2009 , Pages 733-740 ; 10848045 (ISSN) ; Nasiri Avanaki, A. R ; Pakravan, M. R ; Ronasi, K ; Sharif University of Technology
2009
Abstract
Due to special constraints in peer-to-peer (P2P) networks (such as bandwidth limitation) and because of their highly dynamic characteristics, a single node cannot provide a reliable multimedia stream to the receivers. Several multi-sender algorithms are proposed to reliably deliver a media stream to the receiver through the intrinsically unreliable P2P networks. Based on upload bandwidths and availability of peers as well as the bandwidths of the links connecting the senders and the receiver, PROMISE selects a set of active senders to maximize the expected bit-rate delivered to the receiver. By careful investigation of PROMISE, in this paper, we present why and how it deviates from finding...
A multi-sender multicast algorithm for media streaming on peer-to-peer networks
, Article Computer Communications ; Volume 30, Issue 10 , 2007 , Pages 2191-2200 ; 01403664 (ISSN) ; Ronasi, K ; Pakravan, M. R ; Nasiri Avanaki, A. R ; Sharif University of Technology
2007
Abstract
Unlike those on Internet, the media providers on P2P networks are ordinary nodes with limited shared resources such as bandwidth. Multi-sender methods are the best existing solutions to video streaming on P2P networks. In this paper, we propose use of a multicast method on the top of an arbitrary multi-sender method so that all requesting peers receive almost the same expected bit-rate. Experimental results, derived from implementation of the proposed algorithm on Pastry P2P network confirm our claim. Another advantage of our method over the existing methods is its scalability with the number of receivers. © 2007 Elsevier B.V. All rights reserved
Parametric study and computation of seismic performance factors of braced shear panels
, Article Scientia Iranica ; Volume 23, Issue 2 , 2016 , Pages 460-474 ; 10263098 (ISSN) ; Mofid, M ; Sharif University of Technology
Sharif University of Technology
2016
Abstract
By locating a steel shear panel on the intersection point of the X-braces, concentrically or eccentrically braced shear panel (CBFSP or EBFSP) is formed. In this paper, to perform parametric study, 1-story CBFSP and EBFSP models with span length greater or less than height are considered. Using linear static analyses, the effects of size and location of the shear panel on the lateral stiffness of the frame with respect to the moment resisting frame with the same member sections are investigated. Next, for 1- And 3-story models, maximum displacement, along with base shear, and the ratio between the dissipated energy and input energy are examined under 4 ground motion records. Behavior of the...
Vanadyl and molybdenyl phthalocyanines as ionophores for salicylate-selective membranes coated on graphite electrodes
, Article Analytical Letters ; Volume 34, Issue 5 , 2001 , Pages 661-674 ; 00032719 (ISSN) ; Amini, M. K ; Tangestaninejad, S ; Shahrokhian, S ; Sharif University of Technology
2001
Abstract
Salicylate selective electrodes based on oxo(phthalocyanato)-vanadium(IV) [VO(Pc), vanadyl phthalocyanine] and oxo(phthalocyanato)molybdenum(IV) [MoO(Pc), molybdenyl phthalocyanine] are described. The electrodes were prepared by incorporating the ionophores into plasticized poly(vinyl chloride) membranes, which were directly coated on the surface of graphite electrodes. The resulting electrodes demonstrate Nernstian responses over a wide linear range (10-7-10-1 M) salicylate. The electrodes have a fast response time, submicromolar detection limit, and could be used over the pH range of 6-9. The proposed sensors revealed selectivity for salicylate over a number of common inorganic and organic...