Sharif Digital Repository

Liquefaction-induced lateral spreading is a known cause of severe damages to deep foundations during past earthquakes. Lateral spreading often takes place in gently sloping grounds which consisted of saturated loose cohesionless soil deposits. Several researchers during recent years have been studying the behavior of piles and soil-pile interaction under lateral spreading but there are still many unknowns in this regard. Also with observing catastrophic damages during past earthquakes caused by lateral spreading, developing proper mitigation measures for existing vulnerable piles against this phenomenon is a necessary act. In the present research, the behavior of a 3x3 flexible pile group... 

Lateral spreading due to liquefaction and resulting destruction of buildings is important in Iran because of high seismicity and important infrastructure near south and north coasts of Iran. Lateral spreading is vast lateral movement of sloping ground or level ground ending in an opening like river which is caused by earthquake inducedliquefaction. For considering the effects of lateral spreading during design of deep foundations of structures in a susceptible area, one needs to determine the lateral loads on piles under lateral spreading. Present study investigates the behavior of a 3x3 pile group against lateral loads due to lateral spreading with numerical methods using OpenSees software.... 

In this thesis, we propose a new compressed-sensing-based algorithm for unmixing of hyperspectral data, and show that the reconstruction quality could be significantly improved. In addition, we illustrate that by utilizing this approach, we can achieve an approximate estimation of the Point Spread Function (PSF) of the hyperspectral images. In this way, we first assume that the PSF belongs to a specific family of functions, such as Gaussian, then, by sweeping the parameters of the assumed PSF, we obtain the abundance coefficient matrix of the reconstructed image. Now, by choosing the sparsest coefficient matrix as the best one, we estimate the corresponding PSF. Then, we further investigate... 

Since past time, market practitioners and speculators have attempted to use the existent market gaps and opportunities like arbitrage. While some investors buy stocks based on the available financial information of particular companies, others, by using different strategies, try to make profit out of it, based on true realization of the market and its behavior. This strategies will create the profitability by providing different situations including risk hedging and swing trading opportunities .In this context, researchers have designed various strategies for recognizing the assets that have high return potential. One of these strategies in trading with financial tools, is pair trading... 

ALM (Active Learning Method) is based on fuzzy concepts, striving for human-like information processing. Typical fuzzy methods for control and modeling applications rely on linguistic processing with membership functions of the kind in fuzzy rules. ALM, however, processes multiple features of a target by converting each into patterns. This simulates the human approach to the acquisition of knowledge from complex source targets in that it focuses on each feature of the target and processes that information in pattern-like images rather than utilizing numerical interpretations. In ALM, the ink drop spread (IDS) method has been proposed as a means of obtaining useful information... 

When a liquid drop impacts on a hot non-flat surface the curvature of the surface and its geometrical characteristics transmute the physical regimes and their boundary compared to a flat surface impact. The present experimental study is focused on water drop impingement on the mimetic solid semi-cylindrical convex and concave hot surfaces. The thermal versus inertia map of generated regimes is obtained, while some well-known regimes associated with a flat surface are not observed for the present non-flat impacts. The maximum spreading of the droplet is measured at different surface temperatures and impact Weber numbers for the case of droplet impingement on the convex surface. In directrix... 

Liquefaction induced lateral spreading is defined as the lateral displacement of mildly sloping grounds or those ending in free faces as a result of liquefaction in subsurface soil layers. Damages imposed by lateral spreading on pile foundations supporting different types of structures such as ports, bridges and buildings are usually observed in large earthquakes. These potential damages are of high degree of importance in southern and northern coastal areas of Iran where several ports and critical facilities are located. River banks all over the country where bridge piers exist are also among the areas prone to potential damages. Evaluation of the effects of lateral spreading on existing... 

Increasing needs for wireless positioning systems, especially in modern wireless networks, have emerged new trends in research on local positioning systems and algorithms. In this dissertation, several geometric arrangement of positioning systems, different types of wireless measurements used for positioning, and estimation of desirable coordinate parameters based on them are investigated. The set of constrained linearized equations, by introducing intermediate variables are developed and compared with Cramer-Rao bounds. Performance bounds of ToA, TDoA and round-trip ToA systems are obtained and their sensitivity to the location changes of the target and reference stations is examined... 

Due to the short wavelengths in millimeter waves and the specific characteristics of wave propagation in this frequency band, the methods used for modeling channel response in lower frequency bands are not applicable without appropriate modifications. Considering the fact that many obstacles in the channel have sizes comparable to the wavelength (eg branches and tree leaves, brick spacing and roughness height of many surfaces), statistical-empirical methods can be an efficient way of modeling propagation in the presence of such components.
Here an attempt has been made to obtain an appropriate model for the propagation channel using propagation models proposed in the literature. Surface... 

The topic of influencing and regulating the behavior of communities is one which has always gathered attention by various governments, civic institutions, organizations and individuals. Research in this topic has recently been accelerated with the expansion of large scale online social networks. The massive moment of user data which exists in such settings has led to various researchers investigating methods to create new social behaviors such as habits, values and norms, with the core of these methods being the flow of ideas between social actors in order to create such social habits and behaviors.In this context, social norms are a core concept in social sciences and play a critical role... 

Liquefaction-induced lateral spreading has imposed severe damages to many important structures supported on pile foundations during past earthquakes. As a result, evaluation of pile response to lateral spreading is an important step towards safe and resistant design of pile foundations against this destructive phenomenon. The boundary conditions for physical modeling in problems of earthquake geotechnical engineering have significant influence on the test results. In order to reduce the undesirable effects of boundaries on the model responses, the flexible containers are used. The flexible containers are those in which the shear stiffness of the walls is proportional to the soil inside. A... 

The phenomenon of lateral spreading occurs as a consequence of earthquakes induced liquefaction in grounds with mild slopes or ending to an opening. This phenomenon has caused many damages to deep foundations and associated structures. Therefore, it is necessary to study and estimate the forces which may be induced by lateral spreading to these structures. Due to the complex mechanism of the effect of lateral spreading on the piles, various tests have been carried out in the form of shaking table as well as centrifuge tests. According to the results of these tests, the forces applied to the piles are significant and can cause crucial damages to deep foundations. On the other hand, because... 

One of the risk factors of financial assets is liquidity. Identifying factors affecting liquidity helps us to predict stock liquidity and to control the risk of investing. The purpose of this research is to identify these factors in Tehran Stock Exchange. We use the data of 48 companies between1388 and 1392. Our results show that the liquidity follows a weekly and a monthly cycle. Stock return, market return, stock return volatility, market return volatility and trading volume are among the factors which affect stock liquidity. In addition, the reaction of liquidity changes to positive or negative stock return is asymmetric, and the effect of negative stock return is more influential. Our... 

The extraordinary ability of the human brain to solve various problems has led scientists to simulate models of the human brain. One of these simulated models is artificial neural networks. Today, the power of artificial neural networks is not overlooked. The ability of artificial neural networks to solve various types of issues led us to use the thesis to solve some of the graph-based problems. Quite accurately, this graph-based problem is a matter of identifying the source of rumor in a network. In many graph networks, whether natural networks such as the network of neurons in the human brain or synthetic ones such as the types of social networks, it is possible that a rumor spreads across... 

Co-movement between inflation and nominal interest in response to an interest rate shock, dubbed neo-fisherianism, has been the subject of contentious debate since the advent of non-inflationary ZLB environment. We design an economic model rich with banking features to understand the economic responses to permanent and long-term interest rate shocks. We find that responses to a permanent positive interest rate shock depend on the monetary authorities’ speculation of the new long-term inflation rate, with the most probable outcome being a permanent increase in inflation. Responses to a long-term positive interest rate shock depict an increase and then decrease in inflation. We also discover...