Loading...
Search for:
hossein-ghorban--s
0.137 seconds
Total 11517 records
Dominating coloring number of claw-free graphs
, Article Electronic Notes in Discrete Mathematics ; Vol. 45, issue , January , 2014 , pp. 91-97 ; ISSN: 15710653 ; Akbari, S ; Hossein Ghorban, S ; Qajar, S ; Sharif University of Technology
2014
Abstract
Let G be a graph. It is well-known that G contains a proper vertex-coloring with χ(G) colors with the property that at least one color class of the coloring is a dominating set in G. Among all such proper vertex-coloring of the vertices of G, a coloring with the maximum number of color classes that are dominating sets in G is called a dominating-χ-coloring of G. The number of color classes that are dominating sets in a dominating-χ-coloring of G is defined to be the dominating-χ-color number of G and is denoted by dχ(G). In this paper, we prove that if G is a claw-free graph with minimum degree at least two, then dχ(G)≥2
Investigation of the Effect of Interleaved Memory on WCET in Real-Time Embedded System
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Worst case execution time (WCET) and energy consumption are two of the most important design constraints of real-time embedded systems and memory subsystem has a major impact on both of them. Therefore, many recent studies have tried to improve the memory subsystem of embedded systems by using emerging non-volatile memories instead of conventional memories such as SRAM and DRAM. Indeed, the low leakage power dissipation and improved density of emerging non-volatile memories, makes them prime candidates for replacing the conventional memories. However, accessing these memories imposes performance and energy overhead and using them as the code memory may increase the WCET.Furthermore, most...
A rewiring mechanism to improve synchronization in Kuramoto networks
, Article Journal of Statistical Mechanics: Theory and Experiment ; Volume 2022, Issue 11 , 2022 ; 17425468 (ISSN) ; Hesaam, B ; Sarbazi Azad, H ; Sharif University of Technology
Institute of Physics
2022
Abstract
The emergence of synchronization among a set of individual oscillators that are coupled in a network is an amazing physical phenomenon that appears in many different systems, from natural sciences to even human behavior. The phenomenon has attracted the attention of many researchers in many fields of science and engineering by the science behind its unique collective behavior without some kind of external organization. One of the most popular models for the dynamical evolution of coupled phase oscillators is the Kuramoto model, which gives a simple yet powerful formalization together with a numerical measure called the degree of synchronization. The crucial role of structural properties of...
Linearization error in synchronization of Kuramoto oscillators
, Article Applied Mathematics and Computation ; Volume 411 , December , 2021 ; 00963003 (ISSN) ; Baharifard, F ; Hesaam, B ; Zarei, M ; Sarbazi Azad, H ; Sharif University of Technology
Elsevier Inc
2021
Abstract
Synchronization among a set of networked nodes has attracted much attention in different fields. This paper thoroughly investigates linear formulation of the Kuramoto model, with and without frustration, for an arbitrarily weighted undirected network where all nodes may have different intrinsic frequencies. We develop a mathematical framework to estimate errors of the linear approximation for globally and locally coupled networks. We mathematically prove that the eigenvector corresponding to the largest eigenvalue of the network's Laplacian matrix is enough for examining synchrony alignment and that the functionality of this vector depends on the corresponding eigenvalue. Moreover, we prove...
Quantum Walk Application in Search Algorithms
, M.Sc. Thesis Sharif University of Technology ; Karimipour, Vahid (Supervisor)
Abstract
Providing an Algorithm whi? can solve the sear? problem using minimum resources(su? as time, memory and so on)has been ?allenged by computer science experts for many years. By discovering the quantum computer it can be asked that does the quantum algorithm provide a be?er solution to sear? problem? ?e answer is yes. In this thesis the grover’s algorithm, the quantum sear? algorithm using the quantum walk, probabilistic quantum sear? algorithm and finally the two-qubit grover sear? algorithm implementation in physical world will be discussed
Modeling and Simulation of Vacuum Assisted Resin Transfer Molding Process with Flexible Tooling
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Resin Transfer Molding (RTM) which is one of the categories of Liquid Composite Molding (LCM) process, is considered as one of the most important process in polymer composite manufacturing. To improve this manufacturing method and reaching higher qualities, numerous modified methods has been developed. One of these modified methods is Vaccum Assisted Resin Trasnfer Molding with Flexible Tooling which is considerably applicable in manufacturing parts with high quality, large and complex geometry. Although, this manufacturing method has variety of advantages, there are some problems such as void formation making production difficult and dependent to experimental trial and error. So numerical...
Experimental Study of the Performance of Fuel System of Single-Tube Pulse Detonation Engine
, M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad (Supervisor) ; Durali, Mohammad (Co-Advisor)
Abstract
Fuel system is one of the most important parts of pulse detonation engine which has the responsibility of fuel, oxidizer and also purge gas in the different operational frequencies of engine. Although pulse detonation engines are sort of air breathing engines and purge gas and oxidizer one in the same unit in their structure, due to existence idea in the pulse detonation rocket engines coverage of functional condition, fuel, oxidizer and purge gas, will study it in three different structures.
In this study purpose is improvement of the pulse detonation engine of Sharif University which will provide as the possibility of safe functional condition and high operational frequency in...
In this study purpose is improvement of the pulse detonation engine of Sharif University which will provide as the possibility of safe functional condition and high operational frequency in...
Quantitative Assessment of Parkinson Patient’s Health Improvement Using Kinect for Telerehabilitation
, M.Sc. Thesis Sharif University of Technology ; Behzadipour, Saeed (Supervisor) ; Taghizade, Ghorban (Co-Supervisor)
Abstract
Parkinson's disease is the most common progressive neurological disorder after Alzheimer, which is associated with motor disabilities. One of the most effective ways to improve patient’s condition with this disease, is rehabilitation.Assessment of the patient during rehabilitation is very important in order to give a better understanding of patient's status to the specialist, but qualitative assessment methods in traditional rehabilitation are ineffective in fast and accurate evaluation of the patient's condition; and because of their need for patient’s attendance in clinic, they will incur huge medical costs. Therefore, the purpose of the present study is to present a quantitative method to...
Balance Assessment in Parkinson Disease based on a Combination of Posturographic Indices
, M.Sc. Thesis Sharif University of Technology ; Behzadipour, Saeed (Supervisor) ; Taghizadeh, Ghorban (Supervisor)
Abstract
Parkinson's disease is a progressive neurodegenerative disease in which balance disorders are a common symptom. Clinical and non-clinical methods have been developed to evaluate the quality of maintaining balance. Clinical methods include questionnaires and tests that are scored by the therapist and therefore depend on the examiner's skill. On the other hand, there are biomechanical methods that do not depend on the therapist's skill. Posturography -based methods are among the biomechanical tests used today to assess balance. In these methods, some indicators are extracted from the patient's foot center of pressure that can measure the quality of balance. These studies usually examine the...
Classification of Pd Patients Based on the Quality of the Upper Extremity Movements Using a Combination of the Kinematic Indices
, M.Sc. Thesis Sharif University of Technology ; Behzadipour, Saeed (Supervisor) ; Taghizadeh, Ghorban (Supervisor)
Abstract
Parkinson's disease, after Alzheimer's, is the most important and common progressive neurodegenerative disorders. There are various methods for assessing the quality of patients’ movements. One of them is biomechanical methods. The application of these methods in telerehabilitation has been considered by many researchers. Telerehabilitation improves the efficiency of the therapists and reduces problems such as commute costs, traffic stress, and patient fatigue.In the present study, 21 Parkinson patients were treated and evaluated remotely using SANA system. This study aimed to investigate the effects of the therapist absence during the tele-assessment and its impact on the validity and...
The role of reactants and droplet interfaces on nucleation and growth of ZnO nanorods synthesized by vapor-liquid-solid (VLS) mechanism
, Article Journal of Alloys and Compounds ; Volume 455, Issue 1-2 , 2008 , Pages 353-357 ; 09258388 (ISSN) ; Madaah Hossein, H. R ; Ghamsari, M. S ; Sharif University of Technology
2008
Abstract
Short ZnO nanorods and long ZnO nanowires have been produced on SiO2 and Si substrates by VLS and VS mechanisms via a double tube chemical vapor transport and condensation (CVTC) process. The role of reactants and droplet interfaces on the nucleation and growth of ZnO nanorods have been investigated. A conceptual model for nucleation of ZnO nanorods has been proposed by describing the half-oxidation and reduction reactions at the growth front. The importance of Zn vapor in the nucleation phenomena has been studied by changing starting materials. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and EDX analysis have been used to characterize ZnO nanorods and investigate the...
The Development of a Postural Control Model for People with Parkinson’s disease to Predict Rehabilitation Exercises Effects
, Ph.D. Dissertation Sharif University of Technology ; Behzadipour, Saeed (Supervisor) ; Firoozbakhsh, Keikhosrow (Supervisor) ; Taghizadeh, Ghorban (Co-Supervisor)
Abstract
Background: Parkinson’s disease (PD) patients seriously suffer from instability and impaired postural control. Rehabilitation exercises help them to recover their ability through long-term practical sessions. For designing optimal tasks in each session, and in agreement with each patient’s state, it is essential to employ computational models and approaches.Objective: The goal of this study is to develop a computational postural control model of Parkinson’s disease in order to provide new understanding of the postural control in PD, and to gain insight on the effect of balance trainings on PD (the learning dynamics), from the view of this model.Methods: In the first phase of this study, the...
Simulation, optimization & control of styrene bulk polymerization in a tubular reactor
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 32, Issue 4 , 2013 , Pages 69-79 ; 10219986 (ISSN) ; Mohammad, S ; Hossein, A ; Sharif University of Technology
Jihad Danishgahi
2013
Abstract
In this paper, optimization and control of a tubular reactor for thermal bulk post-polymerization of styrene have been investigated. By using the reactor mathematical model, static and dynamic simulations are carried out. Based on an objective function including polymer conversion and polydispersity, reactor optimal temperature profile has been obtained. In the absence of model mismatch, desired product characteristic can also be obtained by applying the corresponding reactor wall or jacket temperature profile. To achieve this temperature trajectory, reactor jacket is divided into three zones and jacket inlet temperatures are used as manipulated variables. Effectiveness of the proposed...
Physical-Layer schemes for wireless coded caching
, Article IEEE Transactions on Information Theory ; Volume 65, Issue 5 , 2019 , Pages 2792-2807 ; 00189448 (ISSN) ; Caire, G ; Hossein Khalaj, B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
We investigate the potentials of applying the coded caching paradigm in wireless networks. In order to do this, we investigate physical layer schemes for downlink transmission from a multiantenna transmitter to several cache-enabled users. As the baseline scheme, we consider employing coded caching on the top of max-min fair multicasting, which is shown to be far from optimal at high-SNR values. Our first proposed scheme, which is near-optimal in terms of DoF, is the natural extension of multiserver coded caching to Gaussian channels. As we demonstrate, its finite SNR performance is not satisfactory, and thus we propose a new scheme in which the linear combination of messages is implemented...
Fast estimation of propagation constants in lamellar gratings needless of solving the eigenvalue equation
, Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 1342-1346 ; 9781728115085 (ISBN) ; Akbari, M ; Hossein Nekuee, S. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Fourier-based modal methods are among the most significant tools for accurate numerical analysis of grating structures. However, they mostly lead to time consuming and memory hungry eigenvalue problems, particularly when large dielectric constants or high contrasts are involved. We have found an asymptotic semi-empirical relationship for the propagation constants of a lamellar grating, obtained from Fourier-based modal methods. Hence, given any truncation order, it is possible to estimate propagation constants without having to solve the eigenvalue equation. We observed propagation constants only depend on permittivities, filling factors, and the unit cell size, while the dependence on the...
On the optimality of 0–1 data placement in cache networks
, Article IEEE Transactions on Communications ; 2017 ; 00906778 (ISSN) ; Motahari, S. A ; Hossein Khalaj, B ; Sharif University of Technology
2017
Abstract
Considering cache enabled networks, optimal content placement minimizing the total cost of communication in such networks is studied, leading to a surprising fundamental 0–1 law for non-redundant cache placement strategies, where the total cache sizes associated with each file does not exceed the file size. In other words, for such strategies we prove that any nonredundant cache placement strategy can be transformed, with no additional cost, to a strategy in which at every node, each file is either cached completely or not cached at all. Moreover, we obtain a sufficient condition under which the optimal cache placement strategy is in fact non-redundant. This result together with the 0–1 law...
On the optimality of 0-1 data placement in cache networks
, Article IEEE Transactions on Communications ; Volume 66, Issue 3 , March , 2018 , Pages 1053-1063 ; 00906778 (ISSN) ; Motahari, S. A ; Hossein Khalaj, B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Considering cache enabled networks, optimal content placement minimizing the total cost of communication in such networks is studied, leading to a surprising fundamental 0-1 law for non-redundant cache placement strategies, where the total cache sizes associated with each file does not exceed the file size. In other words, for such strategies, we prove that any non-redundant cache placement strategy can be transformed, with no additional cost, to a strategy in which at every node, each file is either cached completely or not cached at all. Moreover, we obtain a sufficient condition under which the optimal cache placement strategy is in fact non-redundant. This result together with the 0-1...
Experimental study of the startup performance of ferrofluidic open loop Pulsating Heat Pipes
, Article ASME 2012 Heat Transfer Summer Conference Collocated with the ASME 2012 Fluids Engineering Div. Summer Meeting and the ASME 2012 10th Int. Conf. on Nanochannels, Microchannels and Minichannels, HT 2012, Rio Grande, 8 July 2012 through 12 July 2012 ; Volume 2 , 2012 , Pages 585-591 ; 9780791844786 (ISBN) ; Mehdi, T ; Siamak, K. H ; Mohammad Hassan, S ; Hossein, A ; Mohammad Behshad, S ; Sharif University of Technology
2012
Abstract
Pulsating Heat Pipes (PHPs) are new and promising heat transfer devices. To implement the novel idea to vary the startup performance of a PHP using ferrofluid with and without the application of magnetic field, an experimental investigation is conducted. The effects of several important parameters including working fluid, charging ratio, heat input, ferrofluid concentration, internal pressure, and application of magnetic field on the startup performance of Open Loop Pulsating Heat Pipes (Open Loop PHPs) have been considered and described in detail. Obtained results show that using ferrofluid instead of distilled water can improve the startup performance of PHPs in certain conditions....
Calculation of the Energy Release Rate of Nano-Cracks in FCC Materials Via the Many Body Atomic Scale FEM
, M.Sc. Thesis Sharif University of Technology ; Mohammadi Shodja, Hossein (Supervisor)
Abstract
Since the classical continuum theory fails to deal with the problems associated with defects, stress concentrators, and relevant deformation phenomena in solids, alternative approaches that can detect the atomistic nature of materials' fracture are required. The deficiency of the capture the size effect which yields delusively high values for some components of the stress field right on the edge of the stress concentrators, and its weakness in describing the complex interaction between small inhomogeneities, cracks and the like when they are only a few nanometers apart, are among some of the disadvantages of the classical approach. In recent years, however, atomistic methods are emerging to...
Optimum transmission delay for function computation in NFV-based networks: the role of network coding and redundant computing
, Article IEEE Journal on Selected Areas in Communications ; 2018 ; 07338716 (ISSN) ; Maddah Ali, M. A ; Parsaeefard, S ; Hossein Khalaj, B ; Sharif University of Technology
2018
Abstract
In this paper, we study the problem of delay minimization in NFV-based networks. In such systems, the ultimate goal of any request is to compute a sequence of functions in the network, where each function can be computed at only a specific subset of network nodes. In conventional approaches, for each function, we choose one node from the corresponding subset of the nodes to compute that function. In contrast, in this work, we allow each function to be computed in more than one node, redundantly in parallel, to respond to a given request. We argue that such redundancy in computation not only improves the reliability of the network, but would also, perhaps surprisingly, reduce the overall...