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    Cause-and-effect relationships affecting distribution loss management

    , Article IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT Europe, 11 October 2010 through 13 October 2010 ; October , 2010 ; 9781424485109 (ISBN) Ghofrani Jahromi, Z ; Ehsan, M ; Masjed Jamei, M ; Sharif University of Technology
    2010
    Abstract
    There are a lot of parameters which are decisive in distribution loss management, such as demand value, energy price, etc. In this paper the cause-and-effect relationships among some of these variables are clearly described. The study demonstrates how a variable in the model will change, if an alteration in one of the other variables occurs. The power system variables considered in this study include energy and loss prices, generation and demand values, distribution loss, distribution system age, number of customers connected to the smart grid, distribution network revenue, and so forth. The smart grid impacts can be studied from two different aspects: 1) the communication infrastructure... 

    A deadlock free shortest path routing algorithm for WK-recursive meshes

    , Article 9th International Conference on Distributed Computing and Networking, ICDCN 2008, Kolkata, 5 January 2008 through 8 January 2008 ; Volume 4904 LNCS , 2008 , Pages 280-285 ; 03029743 (ISSN); 3540774432 (ISBN); 9783540774433 (ISBN) Rezazad, M ; Hoseiny Farahabady, M ; Sarbazi Azad, H ; Sharif University of Technology
    Springer Verlag  2008
    Abstract
    In this paper, we investigate an efficient deadlock-free shortest path routing algorithm for WK-recursive mesh networks which has been shown that possess several advantages like suitable to be manufactured by VLSI technology and easy to be expanded. It will be shown that the proposed algorithm requires O(√n) routing steps (where N is the network size) to route the entire network by exploiting either the self-routing or second order routing scheme. © Springer-Verlag Berlin Heidelberg 2008  

    Vorticity-Bases Adaptive Mesh Refinement for Upscaling of Highly Heterogeneous Porous Media

    , M.Sc. Thesis Sharif University of Technology Shahriari, Arjang (Author) ; Firoozabadi, Bahar (Supervisor)
    Abstract
    The results of numerical simulation of underground flows are greatly affected not only by the discretization method of flow equations, but also by the way that the geological domain is upscaled. Including the detailed knowledge of heterogeneous permeability distribution is mostly neither feasible nor computationally efficient. So it is important to develop efficient grid generation and upscaling methods to simplify the fine-scale flow model while still including the impact of the heterogeneities as far as possible. Thus regions where parameters of interest have larger values or higher changes require finer grid blocks and regions with lower values or minor changes should have coarser grid... 

    The triangular pyramid: Routing and topological properties

    , Article Information Sciences ; Vol. 180, issue. 11 , 2010 , p. 2328-2339 ; ISSN: 00200255 Razavi, S ; Sarbazi-Azad, H ; Sharif University of Technology
    Abstract
    In this paper, a new topology for multicomputer interconnection networks, based on triangular mesh, is proposed. The new network, referred to as the triangular pyramid (or tripy for short), has L levels of triangular mesh. We study some basic important properties of the proposed network as well as introduce a routing algorithm for the tripy network based on the routing of triangular meshes. We prove that this form of pyramidal network is Hamiltonian, Hamiltonian-connected, and pancyclic. We also prove that the proposed network is 6-colorable and conduct a brief comparison of the tripy and its traditional pyramid counterpart. Our results show that the proposed network has higher scalability,... 

    Modeling, control and islanding detection of microgrids with passive loads

    , Article Proceedings of EPE-PEMC 2010 - 14th International Power Electronics and Motion Control Conference, 6 September 2010 through 8 September 2010 ; September , 2010 , Pages T11107-T11112 ; 9781424478545 (ISBN) Popov, M ; Karimi, H ; Nikkhajoei, H ; Terzija, V ; Sharif University of Technology
    2010
    Abstract
    This paper presents a control scheme for microgrids with passive loads. The existing control techniques for distributed generation systems are designed to operate either in the grid-connected or in the islanded mode. In the grid-connected mode of operation, a currentcontrolled scheme based on d-q variables is used for the regulation of real and reactive powers of the converter. In the islanded mode of operation, the converter is controlled in the voltage-controlled mode. This paper deals with the modeling of both control schemes. Furthermore, reconnection from the islanded mode to the grid-connected mode based on the use of adequate Phase-Locked Loops (PLLs) has been demonstrated  

    The triangular pyramid: Routing and topological properties

    , Article Information Sciences ; Volume 180, Issue 11 , June , 2010 , Pages 2328-2339 ; 00200255 (ISSN) Razavi, S ; Sarbazi Azad, H ; Sharif University of Technology
    2010
    Abstract
    In this paper, a new topology for multicomputer interconnection networks, based on triangular mesh, is proposed. The new network, referred to as the triangular pyramid (or tripy for short), has L levels of triangular mesh. We study some basic important properties of the proposed network as well as introduce a routing algorithm for the tripy network based on the routing of triangular meshes. We prove that this form of pyramidal network is Hamiltonian, Hamiltonian-connected, and pancyclic. We also prove that the proposed network is 6-colorable and conduct a brief comparison of the tripy and its traditional pyramid counterpart. Our results show that the proposed network has higher scalability,... 

    Diagrammatic approach for constructing multiresolution of primal subdivisions

    , Article Computer Aided Geometric Design ; Volume 51 , 2017 , Pages 4-29 ; 01678396 (ISSN) Bartels, R ; Mahdavi Amiri, A ; Samavati, F ; Mahdavi Amiri, N ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    It is possible to define multiresolution by reversing the process of subdivision. One approach to reverse a subdivision scheme appropriates pure numerical algebraic relations for subdivision using the interaction of diagrams (Bartels and Samavati, 2011; Samavati and Bartels, 2006). However, certain assumptions carried through the available work, two of which we wish to challenge: (1) the construction of multiresolutions for irregular meshes are reconsidered in the presence of any extraordinary vertex rather than being prepared beforehand as simple available relations and (2) the connectivity graph of the coarse mesh would have to be a subgraph of the connectivity graph of the fine mesh. 3... 

    Modeling of crack propagation via an automatic adaptive mesh refinement based on modified superconvergent patch recovery technique

    , Article Engineering Fracture Mechanics ; Volume 75, Issue 10 , 2008 , Pages 2921-2945 ; 00137944 (ISSN) Khoei, A. R ; Azadi, H ; Moslemi, H ; Sharif University of Technology
    2008
    Abstract
    In this paper, an automated adaptive remeshing procedure is presented for simulation of arbitrary shape crack growth in a 2D finite element mesh. The Zienkiewicz-Zhu error estimator is employed in conjunction with a modified SPR technique based on the recovery of gradients using analytical crack-tip fields in order to obtain more accurate estimation of errors. The optimization of crack-tip singular finite element size is achieved through the adaptive mesh strategy. Finally, several numerical examples are illustrated to demonstrate the effectiveness, robustness and accuracy of computational algorithm in calculation of fracture parameters and prediction of crack path pattern. © 2008 Elsevier... 

    High performance dual mesh method to simulated two-phase gravity dominated flows in porous media

    , Article 11th European Conference on the Mathematics of Oil Recovery, ECMOR 2008, Bergen, 8 September 2008 through 11 September 2008 ; 2008 Ashjari, M. A ; Firoozabadi, B ; Sharif University of Technology
    European Association of Geoscientists and Engineers, EAGE  2008
    Abstract
    This paper presents a new combined method for accurate upscaling of two-phase displacements in highly heterogeneous reservoirs. The method has the capability to retain its high performance for various flow regimes, from viscous to gravity dominant displacements, without the need for further modifications and computational steps. Two different grids are incorporated for simulation. The grid on fine scale is used to recognize the complicated physics of flow which depends on dominated driving forces and their interaction with heterogeneity. However, to achieve a fast simulation, the global flow calculation is performed on the coarse scale grid using upscaled equivalent properties. The... 

    A new multi level clustering model to increase lifetime in wireless sensor networks

    , Article 2nd International Conference on Sensor Technologies and Applications, SENSORCOMM 2008, Cap Esterel, 25 August 2008 through 31 August 2008 ; 2008 , Pages 185-190 ; 9780769533308 (ISBN) Masoum, A. R ; Jahangir, A. M ; Taghikhani, Z ; Azarderakhsh, R ; IARIA ; Sharif University of Technology
    IEEE Computer Society  2008
    Abstract
    Most of clustered models in wireless sensor networks use a double-layered structure. In these structures a node is considered as cluster-head and has the responsibility of gathering information of environment. Static attribute is the main disadvantage of these clustering method. because as traffic rises in environment as time passes, cluster-head nodes energy and its close nodes, is consumed rapidly and so these nodes that has important role in data gathering, are break down. This issue is considered as age decrease in network life time and finally, network death. In this paper, a new three-layered dynamic model is introduced that its main goal is to increase network life time. The dynamic... 

    A moving-mesh finite-volume method to solve free-surface seepage problem in arbitrary geometries

    , Article International Journal for Numerical and Analytical Methods in Geomechanics ; Volume 31, Issue 14 , 2007 , Pages 1609-1629 ; 03639061 (ISSN) Darbandi, M ; Torabi, S. O ; Saadat, M ; Daghighi, Y ; Jarrahbashi, D ; Sharif University of Technology
    2007
    Abstract
    The main objective of this work is to develop a novel moving-mesh finite-volume method capable of solving the seepage problem in domains with arbitrary geometries. One major difficulty in analysing the seepage problem is the position of phreatic boundary which is unknown at the beginning of solution. In the current algorithm, we first choose an arbitrary solution domain with a hypothetical phreatic boundary and distribute the finite volumes therein. Then, we derive the conservative statement on a curvilinear co-ordinate system for each cell and implement the known boundary conditions all over the solution domain. Defining a consistency factor, the inconsistency between the hypothesis... 

    Investigation of the Fire-Induced Smoke Flow in the Complex Geometries Using The 3d Numerical Method and the Body-Fitted Curvilinear Coordinates

    , Ph.D. Dissertation Sharif University of Technology Savalanpour Ardebili, Hamid Reza (Author) ; Farhanieh, Bijan (Supervisor) ; Afshin, Hossein (Co-Supervisor)
    Abstract
    With the process of achieving a higher state of social development and technological advances, the need for higher and more strict safety standards has been increased. In this regard, it is of great importance to have an accurate understanding of the fire phenomena and its consequences. Among the adverse effects of fire, a significant percentage of the fire fatalities is related to the fire-induced buoyant gases (smoke) flow which can lead to suffocation. Therefore, it is necessary to know the physics of the fire phenomena well. In fire investigation methods, the numerical study is an appropriate choice, because of the lower executive cost (relative to the experimental study) and the wider... 

    Physical optics integrals evaluation using closed-form expressions and triangular boundary-rectangular mesh algorithm

    , Article IET Microwaves, Antennas and Propagation ; Volume 9, Issue 15 , 2015 , Pages 1803-1808 ; 17518725 (ISSN) Mokhtari Koushyar, F ; Shishegar, A. A ; Sharif University of Technology
    Abstract
    In this study, the authors propose a novel Filon-type integration method that uses error-controllable and frequency-independent closed-form expression to evaluate highly oscillatory physical optics (PO) surface integrals on smooth conducting surfaces. In this method, the phase and amplitude functions of PO integrals for a general parametric surface and incident wave are approximated by second order polynomials, first. Although there are some complicated closed-form expressions for these integrals in the literature, the authors present simple and computationally efficient closed-form expressions for them. For this end, the parametric domain of each resulted integral is meshed by triangular... 

    Power- and performance-efficient cluster-based network-on-chip with reconfigurable topology

    , Article Microprocessors and Microsystems ; April , 2016 ; 01419331 (ISSN) Mehrvarzy, P ; Modarressi, M ; Sarbazi Azad, H ; Sharif University of Technology
    Elsevier  2016
    Abstract
    Topology is widely known as the most important characteristic of networks-on-chip (NoC), since it highly affects overall network performance, cost, and power consumption. In this paper, we propose a reconfigurable architecture and design flow for NoCs on which a customized topology for any target application can be implemented. In this structure, the nodes are grouped into some clusters interconnected by a reconfigurable communication infrastructure. The nodes inside a cluster are connected by a mesh to benefit from the interesting characteristics of the mesh topology, i.e. regular structure and efficient handling of local traffic. A reconfigurable inter-cluster topology then eliminates the... 

    A genetic-based scheduling algorithm to minimize the makespan of the grid applications

    , Article Communications in Computer and Information Science, 13 December 2010 through 15 December 2010 ; Volume 121 CCIS , December , 2010 , Pages 22-31 ; 18650929 (ISSN) ; 9783642176241 (ISBN) Entezari Maleki, R ; Movaghar, A ; Sharif University of Technology
    2010
    Abstract
    Task scheduling algorithms in grid environments strive to maximize the overall throughput of the grid. In order to maximize the throughput of the grid environments, the makespan of the grid tasks should be minimized. In this paper, a new task scheduling algorithm is proposed to assign tasks to the grid resources with goal of minimizing the total makespan of the tasks. The algorithm uses the genetic approach to find the suitable assignment within grid resources. The experimental results obtained from applying the proposed algorithm to schedule independent tasks within grid environments demonstrate the applicability of the algorithm in achieving schedules with comparatively lower makespan in... 

    Generation of Voronoi grid based on vorticity for coarse-scale modeling of flow in heterogeneous formations

    , Article Transport in Porous Media ; Volume 83, Issue 3 , Oct , 2010 , Pages 541-572 ; 01693913 (ISSN) Evazi, M ; Mahani, H ; Sharif University of Technology
    2010
    Abstract
    We present a novel unstructured coarse grid generation technique based on vorticity for upscaling two-phase flow in permeable media. In the technique, the fineness of the gridblocks throughout the domain is determined by vorticity distribution such that where the larger is the vorticity at a region, the finer are the gridblocks at that region. Vorticity is obtained from single-phase flow on original fine grid, and is utilized to generate a background grid which stores spacing parameter, and is used to steer generation of triangular and finally Voronoi grids. This technique is applied to two channelized and heterogeneous models and two-phase flow simulations are performed on the generated... 

    Power- and performance-efficient cluster-based network-on-chip with reconfigurable topology

    , Article Microprocessors and Microsystems ; Volume 46 , 2016 , Pages 122-135 ; 01419331 (ISSN) Mehrvarzy, P ; Modarressi, M ; Sarbazi Azad, H ; Sharif University of Technology
    Elsevier B.V  2016
    Abstract
    Topology is widely known as the most important characteristic of networks-on-chip (NoC), since it highly affects overall network performance, cost, and power consumption. In this paper, we propose a reconfigurable architecture and design flow for NoCs on which a customized topology for any target application can be implemented. In this structure, the nodes are grouped into some clusters interconnected by a reconfigurable communication infrastructure. The nodes inside a cluster are connected by a mesh to benefit from the interesting characteristics of the mesh topology, i.e. regular structure and efficient handling of local traffic. A reconfigurable inter-cluster topology then eliminates the... 

    An efficient hybrid-switched network-on-chip for chip multiprocessors

    , Article IEEE Transactions on Computers ; Volume 65, Issue 5 , 2016 , Pages 1656-1662 ; 00189340 (ISSN) Lotfi Kamran, P ; Modarressi, M ; Sarbazi Azad, H ; Sharif University of Technology
    IEEE Computer Society 
    Abstract
    Chip multiprocessors (CMPs) require a low-latency interconnect fabric network-on-chip (NoC) to minimize processor stall time on instruction and data accesses that are serviced by the last-level cache (LLC). While packet-switched mesh interconnects sacrifice performance of many-core processors due to NoC-induced delays, existing circuit-switched interconnects do not offer lower network delays as they cannot hide the time it takes to set up a circuit. To address this problem, this work introduces CIMA - a hybrid circuit-switched and packet-switched mesh-based interconnection network that affords low LLC access delays at a small area cost. CIMA uses virtual cut-through (VCT) switching for short... 

    Numerical simulation of the effect of visitor's movement on bacteria-carrying particles distribution in hospital isolation room

    , Article Scientia Iranica ; Volume 24, Issue 3 , 2017 , Pages 1160-1170 ; 10263098 (ISSN) Eslami, J ; Abbassi, A ; Saidi, M. H ; Sharif University of Technology
    Abstract
    The aim of this paper is to simulate numerically the airflow induced by a walking visitor and its effects on the contaminant transport and ventilation system effectiveness. To this end, the following models will be used in this study: the Lagrangian Discrete Random Walk (DRW) model to trace the motion of BCPs, the dynamic mesh method to simulate the visitor movement, and the Reynolds Averaged Navier-Stokes (RANS) model to solve the airflow. The validation results of the numerical method are in full agreement with the available experimental data in the literature. The findings of the present study indicate that the visitor's movement has remarkable effect on the basic airflow, and the... 

    Performance of combined vorticity-based gridding and dual mesh method for gravity dominated reservoir flows

    , Article Journal of Petroleum Science and Engineering ; Volume 67, Issue 3-4 , 2009 , Pages 127-139 ; 09204105 (ISSN) Firoozabadi, B ; Ashjari, M. A ; Sharif University of Technology
    2009
    Abstract
    This paper presents a new combined method for accurate upscaling of two-phase displacements in highly heterogeneous reservoirs. The method has the capability to retain its high performance for various flow regimes, from viscous to gravity dominant displacements, without the need for further modifications and computational steps. Two different grids are incorporated for simulation. The grid on fine scale is used to recognize the complicated physics of flow which depends on dominated driving forces and their interaction with heterogeneity. However, to achieve a fast simulation, the global flow calculation is performed on the coarse scale grid using upscaled equivalent properties. The...