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probability-analysis
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Outage probability analysis of a coded cooperative OFDM system in multipath Rayleigh fading channels
, Article 18th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC'07, Athens, 3 September 2007 through 7 September 2007 ; December , 2007 ; 1424411440 (ISBN); 9781424411443 (ISBN) ; Nasiri Kenari, M ; Taherpour, A ; Sharif University of Technology
2007
Abstract
This paper considers a cooperative space-frequency (SF) coded OFDM system and evaluates its performance over quasi-static frequency selective Rayleigh fading channels. An expression for exact outage error probability is derived and its tight closed form lower bound is presented. The tightness of the lower bound is demonstrated through the Monte Carlo simulations. The asymptotic analysis indicates that the proposed protocol achieves full spatial and frequency diversities available in the cooperative communication system. The theoretical analysis of the proposed space-frequency coded cooperation protocol is further confirmed by computer simulations. © 2007 IEEE
Probabilistic Analysis of Soil-Structure Interaction Effects on Seismic Performance of Structures
, M.Sc. Thesis Sharif University of Technology ; Ghannad, Mohammad Ali (Supervisor) ; Mahsouli, Mojtaba (Supervisor)
Abstract
This thesis studies the effect of soil-structure interaction on the seismic performance of structures with due account of uncertainties. The motivation for this study stems from the significant uncertainty in the earthquake ground motion and in the properties of the soil and the nonlinear behavior of the structure. The soil-structure system is modeled by the sub-structure method. The uncertainty in the properties of the system is described by random variables that are input to this model. Monte Carlo sampling is employed to compute the probability distribution of responses that describe the seismic performance of the structure, such as the ductility demand. In each sample, a randomly...
Determination and Quantification of Social, Economic, and Climatic Factors in the Uncertainty of Urmia Lake Restoration Program (ULRP)
, M.Sc. Thesis Sharif University of Technology ; Tajrishi, Massoud (Supervisor)
Abstract
Lake Urmia in northwest Iran is an important water body at the national and international level and plays a significant role in the natural, social, and economic aspects of life in the region. Unfortunately, as a result of natural and anthropologic factors, the lake has suffered a severe water decline in recent decades and was even on the verge of complete drying. Being aware of the catastrophic consequences of lake Urmia's desiccation, a megaproject called Urmia Lake Restoration Program (ULRP) aiming to revive the lake was launched in 2013. Failure in megaprojects is common and frequent in which a high level of uncertainty is one of the main contributing factors. The purpose of this study...
Improving the first-order structural reliability estimation by monte carlo simulation
, Article Proceedings of the Institution of Civil Engineers: Structures and Buildings ; Volume 170, Issue 7 , 2017 , Pages 532-540 ; 09650911 (ISSN) ; Barkhordari, M. A ; Barkhori, M ; Barkhori, M ; Sharif University of Technology
Abstract
The first-order reliability method (FORM) is a well-known procedure for reliability analysis in the engineering community. It provides an efficient way to calculate the failure probability of a structure. However, it introduces an unknown error in the estimations for non-linear limit states. This paper seeks a correction for the FORM by employing Monte Carlo simulation. The proposed method combines the efficiency of FORM with the robustness of the Monte Carlo method. The merits of the proposed method are illustrated through benchmark examples. The results show the high accuracy of the proposed method and a substantial reduction in the number of samples compared with crude Monte Carlo. ©...
Reliability and Probabilistic Seismic Assessment of Fixed Jacket Type Offshore Platforms
,
M.Sc. Thesis
Sharif University of Technology
;
Golafshani, Ali Akbar
(Supervisor)
Abstract
This thesis encompasses a number of issues in earthquake engineering which may appear quite diverse in nature. Several methodological aspects of both conventional and novel approaches to probabilistic seismic hazard assessment are discussed here along with subjects more strictly pertinent to structural and geotechnical engineering. This work, however, has a unique, ultimate goal: to provide procedures for an effective and practical probabilistic estimation of structural demand of offshore platforms due to seismic ground shaking. In modern multi-level design and rehabilitation procedures, structural performance is in fact quantified by deformation demand levels exceeded with a specified...
Incorporation of Forward Directivity in Near-Fault Ground Motions into Probabilistic Seismic Hazard Analysis
, M.Sc. Thesis Sharif University of Technology ; Golafshani, Ali Akbar (Supervisor)
Abstract
Ground motions in close proximity to the causative fault of an earthquake can be significantly affected by the propagation of rupture. In particular, when the rupture and slip direction relative to a site coincide and a significant portion of the fault ruptures towards the site, the ground motion can exhibit the effects of Forward-Directivity (FD). Pulse-like near-fault ground motions resulting from directivity effects are a special class of ground motions that are challenging to characterize for seismic performance assessment. These motions contain a pulse in the velocity time history of the motion, often occurring in the direction perpendicular to the fault rupture at locations near the...
Probabalistic Damage Detection of Ofshore Platforms
, M.Sc. Thesis Sharif University of Technology ; Golafshani, Ali Akbar (Supervisor)
Abstract
High construction and installation costs of offshore platforms, and also harsh environments in which they operate, make health monitoring of these structures more important. Conventional methods to solve the health monitoring problem are deterministic, whereas much uncertainties are imposed to the problem. In most methods of health monitoring methods we try to identify natural frequencies and mode shapes of structures by using its dynamic response. This set of data is then compared to results of modal analysis performed on a finite element model of structure in order to detect any possible damage. In deterministic methods each response of structure is pertained to one damage state, in a...
A Framework to Select the Appropriate Combination of Retrofit and Insurance in Order to Reduce Earthquake Losses
, M.Sc. Thesis Sharif University of Technology ; Haj Kazem Kashani, Hamed (Supervisor)
Abstract
The aim of this research is presentation of A framework to select the appropriate combination of retrofit and insurance in order to reduce earthquake losses. The vulnerability of buildings to earthquakes can lead to significant damage to owners and residents of these buildings. It is imperative that appropriate measures be taken to reduce these adverse effects before the risk occurs. Some of these measures, such as seismic retrofit of buildings, can reduce the vulnerability of buildings and, consequently, financial and human losses. Some other measures like insurance, in the event of an earthquake, can reduce the financial losses incurred by owners and residents of vulnerable buildings....
Probabilistic Framework for Evaluating Community Resilience
, M.Sc. Thesis Sharif University of Technology ; Mahsuli, Mojtaba (Supervisor)
Abstract
This study proposes a probabilistic framework to quantitatively evaluate the resilience of a community comprising a building stock, commercial facilities, and interdependent infrastructure systems. To this end, the proposed framework employs Monte Carlo sampling in which each sample comprises multiple stages. The sample starts with the occurrence of a hazard event. It then follows by evaluating the consequences incurred by the community in the face of the hazard event. It is concluded by simulating the operations aimed at complete recovery of the community comprising inspection, rescue and relief, restoration, and recovery. For this purpose, chains of interacting probabilistic models are...
The Effect of Soil-Structure Interaction on the Probability of Collapse
, M.Sc. Thesis Sharif University of Technology ; Ghanad, Mohammad Ali (Supervisor) ; Mahsuli, Mojtaba (Supervisor)
Abstract
The primary objective of this thesis is twofold: First, the effect of soil-structure interaction (SSI) on the collapse probability of structures are studied. Second, the consequences of practicing the SSI provisions of two prominent seismic design guidelines, i.e., ASCE 7-10 and ASCE 7-16, on the performance of building structures are evaluated and compared. The analyses are conducted for a wide range of dimensionless parameters, which represent different structures on a variety of soil types. To compute the probability of collapse, incremental dynamic analyses are conducted in which In addition to ground motion variability, the uncertainties in the properties of the soil-structure systems...
Sustainability Assessment of Preventive Maintenance Plans (Case Study: Slurry Seal and Thin Overlay)
, M.Sc. Thesis Sharif University of Technology ; Tabatabaee, Nader (Supervisor)
Abstract
Preventive maintenance strategies have been considered by highway agencies in order to increase pavement service life and to reduce the costs associated with pavement maintenance. Due to the increasing concern regarding promoting sustainable pavements, consideration of the environmental, economic and performance factors in devising preventive maintenance strategies is of great importance.This study contributes to developing a multicriteria decision-making tool for sustainability evaluation of pavement preventive maintenance strategies. The developed tool, PaveSAT, considers the greenhouse gas emission, net present value, and pavement performance to rank preventive maintenance schemes using...
Outage probability analysis of uplink NOMA over ultra-high-speed FSO-backhauled systems
, Article 2018 IEEE Globecom Workshops, GC Wkshps 2018, 9 December 2018 through 13 December 2018 ; 2019 ; 9781538649206 (ISBN) ; Azimi Abarghouyi, S. M ; Mahdavifar, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we consider a relay-assisted uplink non-orthogonal multiple access (NOMA) system where two radio frequency (RF) users are grouped for simultaneous transmission, over each resource block, to an intermediate relay which forwards the amplified version of the users' aggregated signals in the presence of multiuser interference to a relatively far destination. In order to cope with the users' ever-increasing desire for higher data rates, a high-throughput free-space optics (FSO) link is employed as the relay-destination backhaul link. Dynamic-order decoding is employed at the destination to determine the priority of the users based on their instantaneous channel state information...
Seismic reliability assessment of steel moment-resisting frames using Bayes estimators
, Article Proceedings of the Institution of Civil Engineers: Structures and Buildings ; 2021 ; 09650911 (ISSN) ; Hajirasouliha, I ; Filizadeh, R ; Sharif University of Technology
ICE Publishing
2021
Abstract
The aim of this study was to develop an efficient probability-based seismic fragility assessment method for steel moment-resisting frames (MRFs). In this method, Bayes estimators are used to improve the accuracy of the results based on new analyses or experimental observations. The efficiency of Bayes estimators in the updating process of fragility curves is demonstrated based on the results of incremental dynamic analysis of three-, five- and seven-storey steel MRFs under a set of 40 spectrum-compatible earthquake ground motions. The results indicate that the constant-hazard-level (engineering demand parameter based) fragility analysis approach leads to less than 6% error in the prediction...
Probabilistic Evaluation of Nonlinear Behavior of Fixed- and Flexible-Base Shear Buildings
, M.Sc. Thesis Sharif University of Technology ; Ghannad, Mohammad Ali (Supervisor) ; Mahsoli, Mojtaba (Supervisor)
Abstract
This thesis revisits the effect of dynamic soil-structure interaction (SSI) on multistory buildings with a probabilistic approach. For this purpose, the relationship between the strength demands of fixed- and flexible-base multi-degree-of-freedom (MDOF) systems, or strength reduction factor thereof, with that of fixed- and flexible-base equivalent single-degree-of-freedom (eSDOF) systems is investigated considering prevailing uncertainties. To this end, Monte Carlo sampling analysis is employed in which a suite of nearly 2000 records are utilized to properly quantify the ground motion uncertainty. The soil-structure system is modeled by the sub-structure method. The uncertainty in the...
Probabilistic Assessment of Flood Risk Using Data-Driven Flood Depth Modeling: A Case Study of Poldokhtar City
, M.Sc. Thesis Sharif University of Technology ; Safaie Nematollahi, Ammar (Supervisor)
Abstract
The present study aims to evaluate the flood risk of Poldokhtar city probabilistically using Monte Carlo Simulations (MCS). Two-dimensional (2D) models, which are highly accurate, have been used widely for flood modeling. However, they are not suitable for applications such as MCSs that need to be repeated many times or real-time flood forecasting applications, which require that flood inundation maps quickly be produced. In the current study, we developed a data-driven surrogate model based on the Least Squares Support Vector Machine (LS-SVM), a supervised machine learning method, to predict flood depth in order to simulate similar results to 2D hydraulic modeling. HEC-RAS was used for 2D...
The effects of viscous dampers on the reliability of steel structures using a PIF index
, Article Proceedings of the Institution of Civil Engineers: Structures and Buildings ; Volume 172, Issue 4 , 2019 , Pages 289-300 ; 09650911 (ISSN) ; Bakhshi, A ; Sharif University of Technology
ICE Publishing
2019
Abstract
A new comparative performance measure based on a structure's seismic fragility curve is introduced. This factor, called the performance improvement factor (PIF), was used to compare the seismic performance and reliability of two structures. Using the PIF, the efficiency of viscous dampers on the behaviour of a weak mid-rise steel structure was investigated. A prototype five-span 12-storey steel frame was equipped with three patterns of viscous dampers and their seismic performance was studied. The distribution of dampers along the height of the structure was optimised in three hazard levels using a genetic algorithm and the structure was subjected to 12 ground motion records scaled to levels...
Bit error probability analysis of UWB communications with a relay node
, Article IEEE Transactions on Wireless Communications ; Volume 9, Issue 2 , 2010 , Pages 802-813 ; 15361276 (ISSN) ; Nasiri Kenari, M ; Aazhang, B ; Sharif University of Technology
2010
Abstract
In this paper, the extension of cooperative communication to the context of TH-UWB is investigated. In particular, the average bit error probability (BEP) is provided for cooperative TH-UWB systems with decode-and-forward relaying protocol. In the considered relay network, UWB links among the nodes are modeled according to IEEE 802.15.4a standards. Our methodology is based on computing the Characteristic Function (CF) of the decision variable at the destination terminal. We use Gaussian quadrature numerical method to approximate the CF of interference component appeared in decision variable term. This technique permits to predict the system performance in different IEEE 802.15.4a defined...