Loading...
Search for:
salehi-ghahfarokhi--khayyam
0.126 seconds
Total 523 records
Using on-the-fly Translation of Temporal Logic to Automata in Model Checking
, M.Sc. Thesis Sharif University of Technology ; Ardeshir, Mohammad (Supervisor) ; Izadi, Mohammad (Supervisor)
Abstract
According to increasing computer systems, needs for verification of such systems with respect to desirable properties is critical. Model checking is one of the best methods of verification. Different methods have been proposed for model checking. The most efficient of these methods is automata-theoretic approach. In this approach, formal specification of desirable property, specified by formula in temporal logics, is translated to corresponding automaton. If the system model is expressed as automaton, the problem of model checking is then reduced to a problem of automata-theory. The question is the following. Are all the computations of the corresponding automaton accepted by the automaton...
Schedule swapping: A technique for temperature management of distributed embedded systems
, Article Proceedings - IEEE/IFIP International Conference on Embedded and Ubiquitous Computing, EUC 2010, 11 December 2010 through 13 December 2010, Hong Kong ; 2010 , Pages 1-6 ; 9780769543222 (ISBN) ; Ejlali, A ; Sharif University of Technology
2010
Abstract
A distributed embedded system consists of different processing elements (PEs) communicating via communication links. PEs have various power characteristics and in turn, have different thermal profiles. With new technologies, processor power density is dramatically increased which results in high temperature. This alarming trend underscores the importance of temperature management methods in system design. The majority of proposed techniques to address thermal issues, impose severe penalties on performance and reliability. We present Schedule Swapping, a technique for reducing peak temperature in distributed embedded systems while satisfying real-time constraints. Contrary to many other...
Optimization of Dynamic Wireless Power Transfer for Maximum Power Transmission to Electric Vehicles
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
Nowadays, due to environmental problems, electric cars are becoming more and more popular. The main drawback of these cars is due to the large volume, weight, and price of the battery and its long charging time. Charging the battery at short intervals or even in moving, can help to use a smaller battery and reduce battery problems. Therefore, the dynamic wireless power transmission technology that provides power without having to stop the car to recharge its batteries can revolutionize the electric car industry. The ever-expanding advance of power electronics and wireless power transmission technologies has made it possible to transfer power to moving electric cars. Barriers to this industry...
Numerical Analyses of Gas Recirculation Effects in Flameless Combustion
, M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad (Supervisor)
Abstract
Flameless combustion in combustion technology is an innovative method with low nox production that few years provided it passes. In this paper the effects of various parameters on flameless combustion chamber with separate fuel and air jets, has been modeled numerically with the help of Fluent 6.3 software. Differences between traditional combustion and flameless combustion were determined and the flame structure has been studied in different scenarios. In numerical modeling, approach were used to modeling turbulence and eddy dissipation concept (EDC) approach use to modeling combustion and turbulence interaction effects. A global Two-step reaction mechanism for propane and a global...
Hierarchical Activity Recognition for PD Patients by Means of an IMU-Based Wearable System
, M.Sc. Thesis Sharif University of Technology ; Behzadipour, Saeed (Supervisor)
Abstract
Parkinson's disease is a progressive and severe neurodegenerative disorder in the central nervous system that is common in adults and, to some extent, in young people. One way to control and improve this disease is through rehabilitation, specifically in the form of rehabilitation activities. Due to the difficulty of travelling to and from the clinic, systems have been developed today that, using inertial sensors, provide the possibility of remotely monitoring this type of treatment up to 95%. In this regard, a system named SEPANTA has been developed at the Djavad Mowafaghian Research Center to diagnose and monitor the rehabilitation activities performed by patients with Parkinson's disease....
Distributed Mechanism for Resource Provisioning in Cloud Computing
, M.Sc. Thesis Sharif University of Technology ; Hemmatyar, Ali Mohammad Afshin (Supervisor)
Abstract
Cloud computing is a paradigm for scalable processing infrastructure which combines distributed software concepts, networks and IT management. Virtualization techniques help to increase productivity from resources. Services are adjusted based on service level agreement with a contract between users and service providers for specifying quality service. In this way, the level of customer satisfaction will be improved. Reliable and flexible management of service level agreements is very important for users and providers. This agreement model is used to prevent the payment of the penalty by providers and minimized interaction between users and providers. Migration from the traditional model to a...
Emerging OCDMA communication systems and data networks [electronic resource]
, Article Journal of Optical Networking ; Volume 6, Issue 9, 1 September 2007, Pages 1138-1178 ; Sharif University Of Technology
Abstract
I present an in-depth review of the trends and the directions taken by researchers worldwide in optical code-division multiple-access (OCDMA) systems. I highlight those trends and features that I believe are essential to the successful introduction of various OCDMA techniques in communication systems and data networks in the near future. In particular I begin by giving a comprehensive review of the construction of optical orthogonal codes (OOCs). Specifically I discuss the recently developed algorithms that are based on matrix algebra, which simplify and enhance the efficiencies of algorithms in OOC generation. In communication systems studies I first focus on and discuss various OCDMA...
Electroplating and characterization of Cr–Al2O3 nanocomposite film from a trivalent chromium bath [electronic resource]
, Article Anti-Corrosion Methods and Materials ; Vol 61, No 4, 2014, 205-214 ; Sadrnezhaad, Khatiboleslam ; Salehi Doolabi, Davood ; Sharif University of Technology
Abstract
The main aim of this study was to improve current efficiency and to obtain thicker coatings via aluminum oxide (Al2O3) addition to the chromium (Cr) (III) bath. Design/methodology/approach ‐ Pure Cr and nanocomposite Cr–Al2O3 coatings were electrodeposited from Cr (III) bath onto cathode copper substrates by conventional method. Dependence of current efficiency to current density, Al2O3 content and particle size were investigated. Findings ‐ Current efficiency increased with Al2O3 amount and decreased with Al2O3 particle size. Maximum current efficiency was achieved at 25 A/dm2 for pure Cr and 30 A/dm2 for composite coatings. Al2O3 bath content, current density and stirring rate increased...
T-shaped handle set-up: effects of handle diameter, between-handle distance, workpiece orientation, working height, and exertion direction on two-handed torque strength, usability, comfort, and discomfort
, Article Ergonomics ; Volume 66, Issue 7 , 2023 , Pages 1015-1030 ; 00140139 (ISSN) ; Dianat, I ; Azghani, M. R ; Asghari Jafarabadi, M ; Parnianpour, M ; Sharif University of Technology
Taylor and Francis Ltd
2023
Abstract
The use of both hands is often required for force/torque exertions, particularly when using hand tools. This study investigated the effects of handle diameter (3–5 cm), between-handle distance (0.5–1.5 shoulder span (SS), workpiece orientation (horizontal/frontal), working height (shoulder/elbow/knuckle), and exertion direction (clockwise/counter-clockwise) on maximum two-handed torque strength, usability and comfort/discomfort while using T-shaped handles. Participants (n = 20) performed 36 experimental conditions. The handle diameter had no significant main effect on torque strength. The 3 cm diameter handle was associated with better usability and comfort compared to other options. Higher...
Spatial heterodyning optical CDMA technique for near-field free-space optical communication systems [electronic resource]
, Article IEEE Journal of Optical Communications and Networking ; Vol. 1, No. 5, PP. 498-511, Oct. 2009 ; Salehi, J. A ; Sharif University Of TechnologyAn automated simple algorithm for realistic pore network extraction from micro-tomography images
, Article Journal of Petroleum Science and Engineering ; Vol. 123, issue , 2014 , pp. 164-171 ; ISSN: 09204105 ; Jamshidi, S ; Salehi, S
2014
Abstract
Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images...
Essentials of sla for l2 teachers: A transdisciplinary framework, joan kelly hall, routledge, New york
, Article Iranian Journal of Language Teaching Research ; Issue 1 , 2020 , Pages 154-156 ; Sharif University of Technology
Urmia University
2020
Influence of pulse parameters on electrocodeposition of Cr-Al2O3 nanocomposite coatings from trivalent chromium bath
, Article International Heat Treatment and Surface Engineering ; Volume 6, Issue 4 , December , 2012 , Pages 178-184 ; 17495148 (ISSN) ; Sadrnezhaad, S. K ; Salehi Doolabi, D ; Asadirad, M ; Sharif University of Technology
2012
Abstract
Cr and Cr-Al2O3 coatings were electrodeposited from Cr(III) bath with both pulsating and direct current onto copper substrates. Pulsating current resulted in homogeneous films of higher Al2O3 content and lower particle agglomeration than the direct current. Differences were more tangible at shorter duty cycles and pulse frequencies. Pulsating current improved both microhardness and corrosion resistance. The presence of alumina nanoparticles resulted in greater current efficiency, higher film microhardness and better corrosion resistance. Maximum current efficiency, highest microhardness and densest electrodeposited coatings were achieved at current density of 20 A dm-2, duty cycle of 40% and...
Optimum receiver design for transmitted-reference signaling [electronic resource]
, Article IEEE Transactions on Communications ; May 2010, Volume 58, Issue 5, P.1589-1598 ; Salehi, J. A ; Sharif University of Technology
Abstract
Autocorrelation receiver (AcR) is usually used as the general receiver for transmitted reference (TR) communication systems on a quite intuitive basis. In this paper, we apply the principle of statistical invariance to obtain the optimum TR receiver on a decision-theoretic basis, and it is shown that the autocorrelation receiver is optimal only in a special case. Performance of the optimum receiver and the suboptimum AcR for some important modulation schemes is also evaluated. The results imply that allocating a part of the transmitted energy and bandwidth to reference pulses would not help improve the performance of the system and the optimal performance might be achieved via much simpler...
Multi-rate and multi-quality of service passive optical network based on hybrid WDM/OCDM system [electronic resource]
, Article IEEE Communications Magazine ; February 2011, Volume 49, Issue 2, PP. S39-S44 ; Salehi, J. A ; Sharif University of Technology
Abstract
In this article we present a new scheme to support multirate and multi-quality-of-service transmission in passive optical networks based on a hybrid wavelength-division multiplexing/optical code-division multiplexing scheme. The idea is to use multilength variable-weight optical orthogonal codes as signature sequences of a hybrid WDM/OCDM system. To provide the requested classes of service, the code weight and code length of MLVW-OOCs are designed based on the characteristics of the requested classes of service. In order to mitigate multiple access interference, we propose to utilize a multilevel signaling technique and interference remover structure based on advanced optical logic gate...
Emerging OCDMA communication systems and data networks [Invited]
, Article Journal of Optical Networking ; Volume 6, Issue 9 , 2007 , Pages 1138-1178 ; 15365379 (ISSN) ; Sharif University of Technology
Optical Society of American (OSA)
2007
Abstract
I present an in-depth review of the trends and the directions taken by researchers worldwide in optical code-division multiple-access (OCDMA) systems. I highlight those trends and features that I believe are essential to the successful introduction of various OCDMA techniques in communication systems and data networks in the near future. In particular I begin by giving a comprehensive review of the construction of optical orthogonal codes (OOCs). Specifically I discuss the recently developed algorithms that are based on matrix algebra, which simplify and enhance the efficiencies of algorithms in OOC generation. In communication systems studies I first focus on and discuss various OCDMA...
Performance of three-level spectrally encoded spreadtime CDMA in the presence of multiple interferences [electronic resource]
, Article IET Communications ; July 2011, Volume 5, Issue 10, P. 1328-1335 ; Mashhadi, Saeed ; Salehi, J. A ; Sharif University of Technology
Abstract
In this study the authors present an in-depth study, analysis and discussion on maximum likelihood (ML)-based receiver for a typical spectrally encoded spread-time CDMA in the presence of multiple narrowband interference (NBI) signals in an additive white Gaussian noise channel. Furthermore, the authors demonstrate that by combining useful properties of ML-based receiver and three-level codes, that is, codes with values of -1, 0, +1, the authors can introduce a new strategy in which superior performance with respect to previous receiver structure based on two-level codes, that is, codes with values of -1, +1, can be attained. With the help of an example, the authors drive, first, the...
Adaptive output feedback tracking controller for a class of uncertain strict feedback nonlinear systems in the absence of state measurements
, Article International Journal of Systems Science ; Volume 43, Issue 2 , 2012 , Pages 201-210 ; 00207721 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
2012
Abstract
In this article, design of an adaptive control scheme for a class of uncertain single-input single-output systems in strict feedback form via a backstepping technique has been proposed. It is assumed that system output and its derivatives are available. By virtue of the observability concept, it is shown that for this class of systems there exists a one-to-one map, which maps output and its derivatives to system states. By means of this mapping and using linearly parametrised approximators, such as fuzzy logic systems or neural networks, the uncertain nonlinear dynamics and unavailable states are estimated. The proposed adaptive controller guarantees that the closed-loop system is uniformly...
Storage-aware value prediction
, Article Proceedings - 13th Euromicro Conference on Digital System Design: Architectures, Methods and Tools, DSD 2010, 1 September 2010 through 3 September 2010, Lille ; 2010 , Pages 722-728 ; 9780769541716 (ISBN) ; Baniasadi, A ; Sharif University of Technology
2010
Abstract
Despite the huge potential, value predictors have not been used in modern processors. This is partially due to the complex structures associated with such predictors. In this paper we study value predictors and investigate solutions to reduce storage requirements while imposing negligible coverage cost. Our solutions build on the observation that conventional value predictors do not utilize storage efficiently as they allocate too much space for small and frequently appearing values. We measure data width requirement and entropy in a subset of predictor resources and show that values stored in predictors show limited sizes and very small entropy. We exploit this behavior and suggest...
A hardware platform for evaluating low-energy multiprocessor embedded systems based on COTS devices
, Article IEEE Transactions on Industrial Electronics ; Volume 62, Issue 2 , 2015 , Pages 1262-1269 ; 02780046 (ISSN) ; Ejlali, A ; Sharif University of Technology
2015
Abstract
Embedded systems are usually energy constrained. Moreover, in these systems, increased productivity and reduced time to market are essential for product success. To design complex embedded systems while reducing the development time and cost, there is a great tendency to use commercial off-the-shelf ("COTS") devices. At system level, dynamic voltage and frequency scaling (DVFS) is one of the most effective techniques for energy reduction. Nonetheless, many widely used COTS processors either do not have DVFS or apply DVFS only to processor cores. In this paper, an easy-to-implement COTS-based evaluation platform for low-energy embedded systems is presented. To achieve energy saving, DVFS is...