Search for: network-configuration
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    Phase identification of singlephase customers and PV panels via smart Meter data

    , Article IEEE Transactions on Smart Grid ; Volume 12, Issue 5 , 2021 , Pages 4543-4552 ; 19493053 (ISSN) Heidari-Akhijahani, A ; Safdarian, A ; Aminifar, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    With proliferation of single-phase rooftop photovoltaic (PV) panels, phase balancing in low voltage (LV) distribution feeders becomes the point of concern. In this way, identification of the hosting phase of connected single-phase customers and PV panels is a prerequisite. This paper proposes an optimization model for the phase identification problem. The objective is to minimize the summation of the absolute error between estimated and measured variables. Smart meters (SMs) data including active and reactive power absorptions/injections, nodal voltage magnitudes, and network configuration data form the input of the model. Potential errors in the input data are captured in the model while... 

    Energy loss estimation in distribution networks using stochastic simulation

    , Article IEEE Power and Energy Society General Meeting, 26 July 2015 through 30 July 2015 ; Volume 2015-September , 2015 ; 19449925 (ISSN) ; 9781467380409 (ISBN) Mahmoodzadeh, Z ; Ghanbari, N ; Mehrizi Sani, A ; Ehsan, M ; Sharif University of Technology
    IEEE Computer Society  2015
    This paper presents an improved stochastic simulation method for calculating current dependent energy losses in distribution networks. The method is based on power load curves and integrates the stochastic nature of the load curves with power and voltage covariance matrices. The method reduces calculation effort using the factor analysis of covariance matrices and provides a few quantities needed to calculate energy losses. The method has no limitation for network configuration and gives accurate results several times faster than other existing methods. Therefore, it is appropriate for considering losses in optimization and decision making purposes in operating and planning of distribution... 

    Superstructure optimization in heat exchanger network (HEN) synthesis using modular simulators and a genetic algorithm framework

    , Article Industrial and Engineering Chemistry Research ; Volume 49, Issue 10 , 2010 , Pages 4731-4737 ; 08885885 (ISSN) Lotfi, R ; Boozarjomehry, R. B ; Sharif University of Technology
    Heat exchanger network synthesis (HENS) is one of the most efficient process integration tools to save energy in chemical plants. In this work, a new optimization framework is proposed for the synthesis of HENS, based on a genetic algorithm (GA) coupled with a commercial process simulator through the ActiveX capability of the simulator. The use of GA provides a robust search in complex and nonconvex spaces of mathematical problems, while the use of a simulator facilitates the formulation of rigorous models for different alternatives. To include the most common heat exchanger structures in the model, a promising superstructure has been used. Allowing nonisothermal mixing of streams in the new... 

    Optimal network configuration considering network losses and service reliability

    , Article IEEE Proceedings 2017 Smart Grid Conference, SGC 2017 ; Volume 2018-January , 2018 , Pages 1-6 ; 9781538642795 (ISBN) Gharebaghi, S ; Izadi, M ; Safdarian, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Distribution networks are designed in loop structure, while they are operated as radial networks. In this regard, the location of normally open (NO) switches is usually determined by either minimizing real power losses or maximizing the reliability level. However, considering both losses and reliability in the decision making procedure may lead to a better solution. To do so, this paper proposes a mathematical model to find the optimal configuration of NO switches such that losses and reliability are optimized. The multi-objective model is scrutinized via weighted sum approach to achieve a single-objective model. The model is formulated in mixed integer quadratically constrained programming... 

    A comprehensive power-performance model for NoCs with multi-flit channel buffers

    , Article Proceedings of the International Conference on Supercomputing, 8 June 2009 through 12 June 2009, Yorktown Heights, NY ; 2009 , Pages 470-478 ; 9781605584980 (ISBN) Arjomand, M ; Sarbazi-Azad, H ; ACM SIGARCH ; Sharif University of Technology
    Large Multi-Processor Systems-on-Chip use Networks-on-Chip with a high degree of reusability and scalability for message communication. Therefore, network infrastructure is a crucial element affecting the overall system performance. On the other hand, technology improvements may lead to much energy consumption in micro-routers of an on-chip network. This necessitates an exhaustive analysis of NoCs for future designs. This paper presents a comprehensive analytical model to predict message latency for different data flows traversing across the network. This model considers channel buffers of multiple flits which were not previously studied in NoC context. Also, architectural descriptions of... 

    An analytical performance evaluation for WSNs using loop-free bellman ford protocol

    , Article 2009 International Conference on Advanced Information Networking and Applications, AINA 2009, Bradford, 26 May 2009 through 29 May 2009 ; 2009 , Pages 568-571 ; 1550445X (ISSN); 9780769536385 (ISBN) Baharloo, M ; Hajisheykhi, R ; Arjomand, M ; Jahangir, A. H ; IEEE Computer Society ; Sharif University of Technology
    Although several analytical models have been proposed for wireless sensor networks (WSNs) with different capabilities, very few of them consider the effect of general service distribution as well as design constraints on network performance. This paper presents a new analytical model to compute message latency in a WSN with loop-free Bellman Ford routing strategy. The model considers limited buffer size for each node using M/G/1/k queuing system. Also, contention probability and resource utilization are suitably modeled. The results obtained from simulation experiments confirm that the model exhibits a high degree of accuracy for various network configurations. © 2009 IEEE  

    A hierarchical routing protocol for energy load balancing in wireless sensor networks

    , Article 2007 Canadian Conference on Electrical and Computer Engineering, CCECD, Vancouver, BC, 22 April 2007 through 26 April 2007 ; 2007 , Pages 1086-1089 ; 08407789 (ISSN) ; 1424410215 (ISBN); 9781424410217 (ISBN) Amini, N ; Miremadi, S. G ; Fazeli, M ; Sharif University of Technology
    In this paper, a hierarchical routing protocol for wireless sensor networks is introduced that aims at reducing the energy imbalance among sensor nodes by integrating the distance of the nodes from the base station into clustering policies. Moreover, the proposed routing protocol does not need any centralized support from a certain node which is at odds with aiming to establish a scalable routing protocol. Mobility management is a salient feature of this protocol that guarantees reliable communications between mobile and static nodes. A simulator was developed in the MATLAB environment to evaluate the performance of this protocol. Simulations on two different network configurations are used... 

    Topological analysis of multi-phase attacks using expert systems

    , Article Journal of Information Science and Engineering ; Volume 24, Issue 3 , 2008 , Pages 743-767 ; 10162364 (ISSN) Shahriari, H. R ; Ganjisaffar, Y ; Jalili, R ; Habibi, J ; Sharif University of Technology
    With the increasing number and complexity of network attacks, the demand for automatic vulnerability analysis tools has increased. The prerequisite of making these tools is to have a formal and precise model of network configurations and vulnerabilities. Utilizing this model, network administrators can analyze the effects of vulnerabilities on the network and complex attack scenarios can be detected before happening. In this paper, we present a general logic-based framework for modeling network configurations and topologies. Then, a number of important and wide-spread network vulnerabilities are modeled as general inference rules based on the framework definitions. We implemented the...