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    Time-variant Seismic Risk Analysis of Transportation Networks Considering Economic and Socioeconomic Impacts

    , M.Sc. Thesis Sharif University of Technology Yazdi-Samadi, Mohammad Reza (Author) ; Mahsuli, Mojtaba (Supervisor) ; Samimi, Amir (Co-Advisor)
    Abstract
    This thesis targets the multidisciplinary area of time-variant seismic risk analysis of transportation networks. For this purpose, a new methodology and a library of probabilistic models are developed. Risk, in this context, denotes the probability of exceeding the sum of direct and indirect losses due to seismic events. Direct economic losses are due to the repair cost of the physical damage in the components of the network, such as bridges. The indirect losses are due to the reduced capacity of the components for traffic flow, which results in increased travel times in the network. This leads to socioeconomic losses. In this research, a reliability-based approach is adopted to carry out... 

    Operation Reserve Determination in a Power System Containing Renewable Generation

    , Ph.D. Dissertation Sharif University of Technology Ghaedi, Amir (Author) ; Abbaspour Tehranifard, Ali (Supervisor) ; Fotouhi Firouzabad, Mahmoud (Co-Advisor)
    Abstract
    Renewable energy resources, e.g. wind, solar and geothermal, experience rapid progresses in electric power industry all over the world. So, it becomes essential that these free-emission electrical energy resources be integrated in the existing generating capacity planning procedures. On the other hand, the uncertain and intermittent nature of these energies has led to some problems in their integration in power systems. The reserve requirement in a renewable-based power system is a main challenge, which has to be addressed properly. In this way, this research presents an analytical approach, based on the modified PJM method, to quantify the risk of renewable energies commitment during the... 

    Seismic Risk Assessment of Tehran Masonry School Buildings

    , M.Sc. Thesis Sharif University of Technology Alimohammadi, Hassan (Author) ; Bakhshi, Ali (Supervisor)
    Abstract
    This thesis aims to assess the seismic risk of the community of schools with masonry buildings in the Tehran metropolitan in the next 50 years and to prioritize the buildings of this community for seismic retrofit based on the optimal mitigation of risk of the community. Tehran is among the largest cities with the highest level of seismic risk in the world, and Masonry buildings are among the structures with poor seismic performance; Therefore, it is essential to conduct a comprehensive and accurate evaluation of the seismic risk of schools, as one of the most critical and sensitive occupancies, in this region and with this type of structure. It is also very beneficial to reduce the seismic... 

    Optimal Seismic Risk Mitigation by Prioritization of Structures for Retrofit

    , M.Sc. Thesis Sharif University of Technology Talebiyan, Hesam (Author) ; Mahsouli, Mojtaba (Supervisor)
    Abstract
    The objective of this thesis is to prioritize a portfolio of buildings for seismic retrofit. A new set of sensitivity measures is proposed to rank the buildings in accordance with the reduction in the loss of the entire portfolio. To this end, various risk measures are differentiated with respect to the cost of retrofit for each building. These risk measures are the moments of the portfolio cost probability distribution which imply the risk-neutral and risk-averse decision making. Two costs are considered: Construction cost due to retrofit and repair cost due to structural and non-structural damage. To quantify the risk, reliability methods are employed in which many interacting... 

    Introducing a Supervisory Hardware Platform for Wireless Body Area Sensor Network with an Anomaly Detection Ability

    , M.Sc. Thesis Sharif University of Technology Zare Dehabadi, Mohammad Saeed (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    Wireless Body Area Network (WBAN) is a set of various physiological sensors for remote monitoring and controlling of the patient’s health status. Detection of anomalies, containing faults and physiological stresses, and distinguishing between them can eliminate the need for constant presence of specialists and decrease the occurrence of False Alarm Rate (FAR).A supervisory hardware platform for WBAN architecture is introduced and implemented in this thesis. The proposed architecture contains three sensors for recording of biomedical signals, heart rate, SpO2 and body temperature simultaneously and transmitting them to central node wirelessly through Wi-Fi standard. This proposed architecture... 

    Fragility and Risk Analysis of Electrical Substation Equipment Using Reliability and Endurance Time Methods

    , M.Sc. Thesis Sharif University of Technology Delaviz Bonab, Arman (Author) ; Esmail Pourestekanchi, Homayoon (Supervisor)
    Abstract
    Electrical substations and its vital components such as switchgears, have experienced severe damage during recent earthquakes, followed by widespread blackouts around the world. To improve the seismic resiliency of power grids and use probabilistic decision-making frameworks, comprehensive fragility data for the different equipment is needed. The purpose of this study is to assess the vulnerability of equipment in substations and to develop fragility curves for this equipment. For this purpose, four main equipment of switchgear, namely circuit breaker, disconnect switch, current transformer and surge arrester, have been modeled in three dimensions and verified. After examining the different... 

    Reliability Assessment of DSSC devices and Optimal Placement of them with the aim of Enhancing Power System Loadability and Reliability

    , M.Sc. Thesis Sharif University of Technology Dorostkar Ghamsari, Mohammad Reza (Author) ; Fotuhi-Firuzabad, Mahmoud (Supervisor)
    Abstract
    One of the important problems in fulfilling the consumers' power demand that has been especially intensified after restructuring is transmission line congestion. To solve this problem, either new transmission lines should be constructed or the existing transmission lines should be better utilized. Construction of new transmission lines is both expensive and time consuming. Therefore, it is usually better to enhance the utilization of the existing transmission assets. FACTS devices have been introduced over the past decades to enhance power systems operation. However, wide scale deployment of them has not occurred yet due to their high initial investment cost and some other problems. In order... 

    Probabilistic Damage Models for Detailed Risk Analysis of Buildings with Reliability Methods

    , M.Sc. Thesis Sharif University of Technology Aghababaei Shahrestani, Mohammad (Author) ; Mahsuli, Mojtaba (Supervisor)
    Abstract
    A probabilistic approach to modeling the seismic damage incurred by structural and nonstructural components is developed in this study. For this purpose, Bayesian linear regression is employed to characterize the epistemic uncertainty in the model. In this approach, regressors are constructed based on the mechanics of damage. In turn, the probability distributions of the model parameters and the model error are quantified by Bayesian regression using real-life data from laboratory experiments and/or post-earthquake inspections of damaged components. The study presents the stepwise procedure of collecting the observations, quantifying the repair costs, developing model forms, performing model... 

    Reliability evaluation of an HVDC transmission system tapped by a VSC station

    , Article IEEE Transactions on Power Delivery ; Vol. 25, issue. 3 , 2010 , p. 1962-1970 ; ISSN: 8858977 Zadkhast, S ; Fotuhi-Firuzabad, M ; Aminifar, F ; Billinton, R ; Faried, S. O ; Edris, A. -A ; Sharif University of Technology
    Abstract
    Reliability evaluation of multiterminal HVDC systems has received very little attention in the past. This paper presents reliability modeling and analysis of an HVDC transmission system incorporating a voltage-sourced converter (VSC) tapping station. The use of VSC tapping stations enables the supply of power along the route to areas with comparatively little consumption. In this paper, a comprehensive detailed reliability model is developed and then converted to a manageable and computationally efficient model. Using this equivalent reliability model, various reliability indices are calculated at the load point of the system and the impacts of the VSC tapping station on these indices are... 

    Reliability evaluation of an HVDC transmission system tapped by a VSC station

    , Article IEEE Transactions on Power Delivery ; Volume 25, Issue 3 , April , 2010 , Pages 1962-1970 ; 08858977 (ISSN) Zadkhast, S ; Fotuhi Firuzabad, M ; Aminifar, F ; Billinton, R ; Faried, S. O ; Edris, A. A ; Sharif University of Technology
    2010
    Abstract
    Reliability evaluation of multiterminal HVDC systems has received very little attention in the past. This paper presents reliability modeling and analysis of an HVDC transmission system incorporating a voltage-sourced converter (VSC) tapping station. The use of VSC tapping stations enables the supply of power along the route to areas with comparatively little consumption. In this paper, a comprehensive detailed reliability model is developed and then converted to a manageable and computationally efficient model. Using this equivalent reliability model, various reliability indices are calculated at the load point of the system and the impacts of the VSC tapping station on these indices are... 

    Reliability modeling of dynamic thermal rating

    , Article IEEE Transactions on Power Delivery ; Vol. 28, issue. 3 , 2013 , p. 1600-1609 ; ISSN: 8858977 Shaker, H ; Zareipour, H ; Fotuhi-Firuzabad, M ; Sharif University of Technology
    Abstract
    In this paper, a Markov model for reliability analysis of transmission lines equipped with a dynamic thermal rating (DTR) system is proposed. Moreover, a fuzzy procedure is proposed to determine an annual equivalent fuzzy DTR number to represent hourly variations of the line DTR. To implement the fuzzy annual DTR in composite system reliability analysis, an interactive method resolution technique for solving fuzzy optimization problems is developed. This method is chosen to address the fuzzy constraints associated with the lines equipped with the DTR system. Numerical results are presented using the 24-bus IEEE RTS, and demonstrate the validity of the proposed approaches  

    Reliability modeling of dynamic thermal rating

    , Article IEEE Transactions on Power Delivery ; Volume 28, Issue 3 , 2013 , Pages 1600-1609 ; 08858977 (ISSN) Shaker, H ; Zareipour, H ; Fotuhi Firuzabad, M ; Sharif University of Technology
    2013
    Abstract
    In this paper, a Markov model for reliability analysis of transmission lines equipped with a dynamic thermal rating (DTR) system is proposed. Moreover, a fuzzy procedure is proposed to determine an annual equivalent fuzzy DTR number to represent hourly variations of the line DTR. To implement the fuzzy annual DTR in composite system reliability analysis, an interactive method resolution technique for solving fuzzy optimization problems is developed. This method is chosen to address the fuzzy constraints associated with the lines equipped with the DTR system. Numerical results are presented using the 24-bus IEEE RTS, and demonstrate the validity of the proposed approaches  

    Time-variant reliability-based prediction of COVID-19 spread using extended SEIVR model and Monte Carlo sampling

    , Article Results in Physics ; Volume 26 , 2021 ; 22113797 (ISSN) Shadabfar, M ; Mahsuli, M ; Sioofy Khoojine, A ; Hosseini, V. R ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    A probabilistic method is proposed in this study to predict the spreading profile of the coronavirus disease 2019 (COVID-19) in the United State (US) via time-variant reliability analysis. To this end, an extended susceptible-exposed-infected-vaccinated-recovered (SEIVR) epidemic model is first established deterministically, considering the quarantine and vaccination effects, and then applied to the available COVID-19 data from US. Afterwards, the prediction results are described as a time-series of the number of people infected, recovered, and dead. Upon introducing the extended SEIVR model into a limit-state function and defining the model parameters including transmission, recovery, and... 

    Reliability modeling of multistate degraded power electronic converters with simultaneous exposure to dependent competing failure processes

    , Article IEEE Access ; Volume 9 , 2021 , Pages 67096-67108 ; 21693536 (ISSN) Samavatian, V ; Fotuhi Firuzabad, M ; Dehghanian, P ; Blaabjerg, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    Depending on the application in which power electronic converters (PECs) are deployed, failure processes may endanger the desirable performance of PECs. This paper offers holistic insights on reliability modeling of PECs considering dependencies in two simultaneous failure processes, namely gradual wearing-out degradation and vibration sudden degradation. While sudden and gradual degradation processes may individually affect the useful lifetime of PECs, their mutual interdependencies could significantly accelerate the aging mechanisms. A new analytical model for reliability assessment of PECs is proposed that can capture such mutual interdependence of simultaneous failure processes. The... 

    A reliability model of large wind farms for power system adequacy studies

    , Article IEEE Transactions on Energy Conversion ; Volume 24, Issue 3 , 2009 , Pages 792-801 ; 08858969 (ISSN) Salehi Dobakhshari, A ; Fotuhi Firuzabad, M ; Sharif University of Technology
    2009
    Abstract
    In this paper, an analytical approach for the reliability modeling of large wind farms is presented. A systematic method based on frequency and duration approach is utilized to model a wind farm like a multistate conventional unit, where the probability, frequency of occurrence, and departure rate of each state can be obtained using the regional wind regime of wind farm and wind turbine characteristics. The proposed method is capable of finding both annual frequency and average time of load curtailment analytically in the presence of wind power. A wind farm in the northern region of Iran with the wind speed registration of one year is studied in this paper. To accommodate time-varying... 

    Evaluation of UPFC impacts on power system reliability

    , Article Transmission and Distribution Exposition Conference: 2008 IEEE PES Powering Toward the Future, PIMS 2008, Chicago, IL, 21 April 2008 through 24 April 2008 ; May , 2008 ; 9781424419036 (ISBN) Rajabi Ghahnavieh, A ; Fotuhi Firuzabad, M ; Feuillet, R ; Sharif University of Technology
    2008
    Abstract
    This paper evaluates the reliability impact of UPFC application in power system. The paper proposes a new reliability model for the UPFC which is capable of considering different operating states of UPFC. The model is then applied to a test system to study the reliability impacts of UPFC. The impacts of operating points of different states of the model on the system reliability are analyzed. The role of model parameters in reliability impacts of UPFC is analyzed through the sensitivity analysis. A comparative study is finally conducted to illustrate the applicability of the proposed model compare to that of existing UPFC reliability models. The abilities and deficiencies of the proposed... 

    A low-overhead and reliable switch architecture for Network-on-Chips

    , Article Integration, the VLSI Journal ; Volume 43, Issue 3 , June , 2010 , Pages 268-278 ; 01679260 (ISSN) Patooghy, A ; Miremadi, S. G ; Fazeli, M ; Sharif University of Technology
    2010
    Abstract
    This paper proposes and evaluates Low-overhead, Reliable Switch (LRS) architecture to enhance the reliability of Network-on-Chips (NoCs). The proposed switch architecture exploits information and hardware redundancies to eliminate retransmission of faulty flits. The LRS architecture creates a redundant copy of each newly received flit and stores the redundant flit in a duplicated flit buffer that is associated with the incoming channel of the flit. Flit buffers in the LRS are equipped with information redundancy to detect probable bit flip errors. When an error is detected in a flit buffer, its duplicated buffer is used to recover the correct value of the flit. In this way, the propagation... 

    Spare parts management algorithm for wind farms using structural reliability model and production estimation

    , Article IET Renewable Power Generation ; Volume 10, Issue 7 , Volume 10, Issue 7 , 2016 , Pages 1041-1047 ; 17521416 (ISSN) Mani, S ; Oraee, A ; Oraee, H ; Sharif University of Technology
    Institution of Engineering and Technology 
    Abstract
    Doubly fed induction generators (DFIGs) are widely used in wind power systems; hence their reliability model is an important consideration for production assessment and economic analysis of wind energy conversion systems. However, to date mutual influences of reliability analysis, production estimations and economic assessments of wind farms have not been fully investigated. This study proposes a reliability model for DFIG wind turbines considering their subcomponent failure rates and downtimes. The proposed production estimation algorithm leads to an economic assessment for wind farms. A comprehensive spare parts management procedure is then presented in the study. As a case study,... 

    A modeling framework for reliability of erasure codes in SSD arrays

    , Article IEEE Transactions on Computers ; Volume 69, Issue 5 , May , 2020 , Pages 649-665 Kishani, M ; Ahmadian, S ; Asadi, H ; Sharif University of Technology
    IEEE Computer Society  2020
    Abstract
    Emergence of Solid-State Drives (SSDs) have evolved the data storage industry where they are rapidly replacing Hard Disk Drives (HDDs) due to their superiority in performance and power. Meanwhile, SSDs have reliability issues due to bit errors, bad blocks, and bad chips. To help reliability, Redundant Array of Independent Disks (RAID) configurations, originally proposed to increase both performance and reliability of HDDs, are also applied to SSD arrays. However, the conventional reliability models of HDD RAID cannot be intactly applied to SSD arrays, as the nature of failures in SSDs are totally different from HDDs. Previous studies on the reliability of SSD arrays are based on the... 

    A goal programming approach for optimal PMU placement

    , Article International Review on Modelling and Simulations ; Volume 6, Issue 2 , April , 2013 , Pages 490-497 ; 19749821 (ISSN) Khiabani, V ; Hamidi, M ; Farahmand, K ; Aghatehrani, R ; Sharif University of Technology
    2013
    Abstract
    This article proposes a multi-objective goal programming based approach with two objectives of maximizing the reliability and minimizing the placement cost of Phasor Measurement Units (PMUs) for full observability in power systems. The weighted sum goal programming formulation incorporates the reliability of individual PMUs and finds a placement to resolve the conflicting objectives of minimum number of PMUs cost-wise and maximum level of system-wide reliability. This multi-objective problem is formulated as a nonlinear goal programming model in which weights are associated with the objectives. The model is solved for several weight scenarios for the IEEE 14, 30, 57 and 118 bus test systems....