Sharif Digital Repository

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... 

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... 

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... 

Continuous-time Stochastic Game (CTSG) can be seen as a proper model to analyze probabilistic, nondeterministic, and competitive behaviors as found in Stochastic Multi-Player Game (SMG). The difference is that in an SMG, the system under design is analyzed in the discrete-time setting. In comparison, in a CTSG, the system transitions occur in the continuous-time setting with exponentially distributed delays. This thesis focuses on the model checking of CTSGs with bounded transition rates. We present a uniformization-based algorithm to approximate the optimal time-bounded reachability probabilities with an arbitrary error bound. To illustrate the strength points of our algorithm, we compare... 

Risk management is one of the most important topics in banking. Risk management in banking is divided to several categories including credit risk. Credit risk is also divided to individual credit risk and portfolio credit risk. In Iran many of banks have worked on individual credit risk models, but few of them have worked on portfolio models because these models have developed only in recent years. In our project we present three categories of credit risk models and then analyze the data of a private bank in Iran with CreditPortfolioView model. In CreditPortfolioView model, macroeconomic parameters are used to analyze the correlated behavior of individuals as a benchmark in different... 

The HIPS is a safety integrity system that is designed to provide overpressure protection that is at least equivalent in reliability to a mechanical relief device. In this study, the performance evaluation of HIPS in Assaluyeh gas Refiner is studied.In the first stage, over pressure analysis is compiled using dynamic simulation and API RP 520 and the recommended HPPS design procedure is presented. Also, The High Integrity Protection Systems (HIPS) further reduced the relief load and even eliminated the relief from the stabilizer tower for the scenarios tested.In this project, following a detailed study of the commissioning process and its criticalities, Hazop is selected as the most suitable... 

This study proposes a probabilistic framework to quantify the seismic resilience of urban natural gas distribution networks. Infrastructure resilience is defined as the ability to maintain performance after a hazard or, in case of a loss of performance, return to the minimum desired level in the optimal time. The framework presented in this research is comprised of multiple interconnected probabilistic models. These models work in harmony to characterize the impact of the earthquake on various infrastructures such as the buildings and urban gas distribution network components, as well as the probable consequences of the earthquake. The post-earthquake recovery of the gas distribution network... 

After Hume’s skeptical argument on the concept of causality and establishing the regularity theory of causation by him, it seemed that the regularity theory might not respond to irrelevance problems and spurious regularities. In the second half of the twentieth century, attempts were made, e.g. Hans Reichenbach's proposal of the “common cause principle,” for solving the problems of regularity theory which resulted in probabilistic approach to causal relationships. The importance of the common cause principle is that it has inspired the “Causal Markov Condition” which is the most fundamental condition for causal networks. The causal Markov condition states that a variable X is... 

Aging Aircraft with life extension, Conversion or replacing them with new aircrafts are of the decisions in front of airliners after their retirement. Decision making for repairing aircraft to increase its life is depended upon various parameters like its cost and reliability. The thesis evaluated the reliability of the structure of an aircraft before and after life extension. For this purpose, using the statistical data, the predominant failure modes are studied and based on these failure modes the border between fracture and health of the structure which is called limit state function is defined. After this using first order reliability method (FORM), the probability of the failures is... 

This research has been worked out in two main parts and it is tried to reach a high level of Safety Integrity in Safety Instrumented Systems using in Oil, Gas and Petrochemical industries. The first part involves an overview of system risk analysis and initial investigation of Safety Integrity Level as a new parameter in safety instrumented systems which are very important section of Safety engineering during last couple of years. According to the fact that the available papers and articles in this area are very limit; we have faced a lot of problem in doing research and actually to be honest; all available resources have been focused plus the related standards. The second part is about... 

In Mechanical systems there is always possibility of statical and dynamical following force. These forces are generated due to aerodynamic pressure, temperature gradient, and jet thrusters. In unstabel systems, if the value of this force exceeds a certaim amount the system becomes unstable. This value is called as critical force. In order to analyse these systems, fisrt of all, the governing dynamic equations are obtained by using the Galerkin-Ritz method. Then, by utilising the modal analysis, these equation are uncoupled. And then, the Ito set of equations are derived. By utilising the Lyapanov method, Ito equations are transfered to another state. and using the fokker-planc equation the... 

Overpressure protection and flare loading network are critical challenges faced by the Oil & Gas and chemical industries. Whether they are new facilities or aging ones, integrity management of overpressure and flaring systems remain significant throughout the life of the planet. One of the most important ways for protection of over pressure and depressurizing to flare header through pressure safety valve is implementation of safety instrument system (SIS). Application of safety instrumented systems for the process industries causes significant reduction of flaring load and loss prevention of valuable materials through increase protection layer availability and over pressure risk reduction.... 

Non-Orthogonal multiple access (NOMA) has been considered as a promising multiple access technique for the 5th generation (5G) of wireless networks. In contrast to orthogonal multiple access, NOMA supports more than one user in each subchannel and thus, improve spectral efficiency. On the other hand, energy efficiency which is another key consideration in future 5G networks, can be improved by energy harvesting (EH) methods. In the NOMA scheme, the user with the better channel condition performs successive interference cancellation (SIC) to detect the data of the user with the worse channel condition and then subtract it from the received signal to decode its own data. Since the data of the... 

In the present paper we construct stock price processes with the same marginal log- normal law as that of a geometric Brownian motion and also with the same transition density (and returns’ distributions) between any two instants in a given discrete-time grid. We then illustrate how option prices based on such processes differ from Black and Scholes’, in that option prices can be either arbitrarily close to the option intrinsic value or arbitrarily close to the underlying stock price. We also explain that this is due to the particular way one models the stock-price process in between the grid time instants which are relevant for trading
 

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... 

Safety of concrete gravity dams under dynamic loading that cause from earthquakes is an important aspect of research.as we know, dam structure response is related to type of loading, properties of concrete and foundation material, so according to the uncertainties of these random variables, in this research we calculate the response (stresses) of structure for different value of random variables that have their own probability distribution type. Nonlinear plasticity damage model of dam is implemented in ABAQUS and for reliability analysis we use Latin Hypercube Sampling (LHS). Sensitivity results show that PGA of earthquake and Special Energy (Gf) of concrete in comparison with concrete... 

Phenomena such as will and volition, the emergence of qualities, internal and external feelings are the main problems related to consciousness. Consciousness is one of the oldest and, of course, most complex problems in science, and scientists are striving to provide a suitable explanation for this problem, but a complete answer has not yet been presented. Quantum consciousness is also an attempt to provide a suitable answer using the theory of quantum mechanics as the most fundamental scientific theory regarding the behavior of matter. In this area, the Orch OR theory by Penrose-Hameroff, the Henry P. Stap’s theory of quantum consciousness, and the Eccles-Beck’s theory of quantum... 

Since the beginning of philosophy in ancient Greek, making use of the partial induction has been a challenging issue. The diversity of the challenges, from the fallibility of induction to the peculiar consequences brought about by using inductive inference, has raised seemingly impassable blockages in the way of rational using of inductive inference. But philosophers who are optimistic about induction, always seek novel solutions which can overcome the existing problems of the rational utilization of induction. Mohammad Baqer Sadr is one of these philosophers who, in his book Logical Foundations of Induction, has done a delicate and creative work to overcome these barriers. In this thesis,... 

Molecular communication is a new paradigm in communication science, which studies opportunities and challenges of information transmission in nanoscale. Unlike the classical communication, which uses electro-magnetic waves as signal carriers, in this new method of communication, tiny agents in molecular scale are the main information barriers. In this sense, studying molecular communication requires theoretical development and updating some well-known techniques of classical communications.Although there have been some successful attempts to implement communication systems based on molecular communication, the field is still in the theoretical development phase. In this thesis, we have tried...