Sharif Digital Repository

One the most important issues in most of embedded systems is reliability and fault tolerance.Ensure of correct operation and evaluate reliability and fault tolerance of embedded proces-sors as a critical part of embedded systems, would be necessary. Fault injection is one themostly used methods for evaluating those features. Using FPGA devices is a good alterna-tive for time consuming simulation-based fault injection method because of their speed. But,there are some critical issues in FPGA-based fault injection methods which are controllabil-ity and observability. In addition to need for efficient and applicable observation and controlmechanism to handle fault injection experiments, a... 

Quantum key distribution is one of the practical quantum information technologies in labo- ratories with existing equipments.In quantum key distribution protocols, the main challenge is the secrecy of key distribution. One of the new methods of quantum channel error esti- mation is the use of weak measurement. In this thesis, after introducing the main quantum key distribution protocols, we introduce weak measurement and sequential weak measure- ment concepts: the weak measurement methods are exployed to obtain the phase difference between two polarizations with high accuratly. It is also used for in line monitoring and error estimation parameters in some quantum key distribution protocols.... 

In this thesis, we present some extension of Burton and Kirk fixed point theorem for the sum of two nonlinear operators, which one of them is compact and the other one is strict contraction; and we investigate the existence of fixed point where these two operators don’t need to be weakly continuous. Next, we will check the necessity of some conditions, like being strict contraction or compactness, in some specific Banach spaces, such as reflective spaces or Banach spaces equipped with uniformly convex norm.Finally, we analysis the existence of the solution for integral equations in L1 space by using the expressed theorems  

Based on modern finance theory, valuation should not depend on nominal stock prices. However, evidence shows that the nominal price of stocks does matter in the U.S. stock market. In this paper, we examine the effect of nominal share prices on stock returns, using data between 2009 and 2017 form the Tehran Stock Exchange. Our results indicate that there is no significant relationship between nominal price and return on the Tehran Stock Exchange. By controlling for different important variables, the return differential between high price and low price stocks is insignificant and the results are robust to various specifications and tests. Furthermore, by using event study under the market... 

This research has been surveyed the impact of intermediate skilled and high skilled human labor force on the productivity of manufacturing sectors by the Nelson & Phelps and also Lucas approaches. first model is related to the level of productivity and the second model is related to the growth of it. We has been prepared the needed statistics from the raw figures of iran statistics center. regression analysis has been done on the basis of panel data model by the use of stata software. the results show that not good efficiency to optimize technology factor of Cobb-Douglas model although it shows higher marginal labor productivity of high skilled human labor force. we has proposed some... 

Most propulsion systems use nozzles to increase the velocity of exhaust gas. Therefore, the efficiency of nozzles is important. Losses due to geometry and physical phenomena inside the nozzle define this efficiency. The length and divergence angle of the nozzle, the throat diameter, the Reynolds number, and the specifications and the combinations of fuel have a direct impact on these losses. Solid propellant rockets are widely used and today optimization of rockets is most noticeable. On the other hand, in different phases of design and optimization, empirical experiments are necessary, which are costly in real dimensions. The use of laboratory motors with specific considerations decrease... 

Nanolaunchers are launch vehicles capable of carring light payloads (under 50 kg) to Low Earth orbit and received much attention in the few past years. Launching the nanosatellites grown about 30 times from 2008 to 2017. Since this category of launch vehicles has fewer developing costs and lower thechnology level, they fit developing space technology in our country. Conversely, the demand of high propellant mass fraction and specific impulse may be a serious difficulty to attain this technology.The only operating nanolauncher in the world is SS-520-5 which belongs to Japan and is a three-stage solid propellant launcher. The goal of this project is also the conceptual design and feasiblity... 

This thesis is conducted to study acceleration effect on the burning rate augmentation of a solid propellant. A centrifugal experimental setup is designed to obtain a uniform acceleration field. An internal burning tube is used as grain, so acceleration vector is always perpendicular to burning surface of propellant. Inner radius of tube is small, so the magnitude of acceleration increases as the grain burns back. The pressure of combustion chamber was changed from 30 bar to 80 bar by changing the nozzle throat and the magnitude of acceleration changed from 2g to 60g by changing the rotational speed of SRM. Burning time of all tests was below 2 sec. due to small web of the grain. Pressure of... 

The present research focuses on the simulation of the metallic powder compaction process with the Peridynamics theory. Various methods are exploited to simulate this process in literature. Studying the nonlinear behavior of powders includes different phenomena such as dislocation and grain boundary, making it complicated. However, numerous research has been shaped to consider these phenomena on the micro-scale. There is also another batch of nano-scale studies underway. In this class of simulations, considering atoms as rigid particles, interatomic potentials, and molecular dynamics methods are used. Because of atomic-scale precision, this approach has very high accuracy. The massive... 

Real estate section is an integral part of any economy whose cycles have considerable effects on other different markets. It attracts much attention by various economy agents for different reasons. However, some specific features of the market render it prone to consecutive boom-bust cycles. Some of these features are originated from fundamental traits and especially building process and production technology of housing. Also, taking into account that real estate is considered an important asset; it is vulnerable to another factor which even exacerbates the cycles. This factor -Information cascade- makes cycles more unstable by causing "Herd behavior" which is the subject of study in this... 

Neural field models with delays define a useful framework for modeling macroscopic parts of the cortex involving several populations of neurons. Nonlinear delayed integrodi fferential equations describe the spatio-temporal behavior of these fields. We also present a study of the numerical computation of these solutions in a special case. Another original contribution of ours is the definition of a Lyapunov functional and the result of stability it implies. We illustrate our work on a variety of examples that are relevant to modeling in neuroscience.
 

The aim of this study is to remove pharmaceutical pollutants through a photocatalytic approach. A layered double hydroxide (LDH) structure was synthesized with the assistance of a metal-organic framework (MOF). Initially, MIL-101(Cr) was synthesized using trivalent chromium ions and subsequently transformed into a layered double hydroxide structure with divalent nickel ions. To further enhance this process, MIL-88(Fe) was prepared using trivalent iron ions, composited with MIL-101(Cr), and then converted into an LDH structure using divalent nickel ions. The resulting photocatalytic composite was fully characterized, and its efficiency in degrading the pharmaceutical compound meropenem was... 

Over the years, as machines have been invented, their maintenance and repair have consistently been regarded as critical concerns. Oil analysis techniques are an effective method for monitoring the condition of mechanical equipment. Since filters in these devices continually absorb and remove a significant portion of particles from the lubricant, the selection of appropriate filters is crucial. While filters positively affect machine performance, they can also negatively impact oil condition monitoring. To mitigate this negative effect and improve the predictive accuracy of equipment health monitoring, oil filter analysis was conducted. In this research, analytical ferrography tests were... 

Each year, a considerable amount of waste tires is disposed of in landfills, causing significant environmental concerns. One potential solution to mitigate these effects is the partial replacement of natural fine aggregates in concrete with recycled crumb rubber. Although the inclusion of crumb rubber typically results in reduced compressive strength and elastic modulus, previous studies have shown that rubberized concrete can still be viable for structural applications. In reinforced concrete structures, adequate bond between the steel reinforcement and surrounding concrete is essential; hence, the concept of development length is used to ensure proper anchorage. Where providing the... 

Commercial banks have got an important role in our lives and every one can mention veriety functions for them. The more benefits can bring the more risks can couse as the old tradeoff between risk and return. One of the important risks that can bring about lots of problem for banking system is liquidity risk. Being not able to respond customers’ liquidity demand is named the liquidity risk. Banks keep some reserve in cental bank to respond other banks’ liquidity demands in payment system. Shortage of this reserve will cause customer and central bank punishments and penalties. Excess reserve on the other hand has opportunity cost. Hence an optimum amount of liquidity resrve must be held in... 

One of the important questions in mathematics is generalized. In case of metric spaces, one of the questions is: Can we extend notions of Riemannian geometry to arbitrary metric spaces smoothly? Ricci curvature is one of the most important concepts in differential geometry. Ricci curvature is defined for the Riemannian manifold and has many applications in mathematics and physics like Einstein’s equation in relativity theory. There is a good notion for a metric space having “sectional curvature bounded below by K” or “sectional curvature bounded above by K”, due to Alexandrov. Can we define the concept of Ricci curvature in metric space? A motivation for this question comes from Gromov’s... 

Seismic design codes reduce loads by using response modification factor. Because of the reserved strength in structural elements and capacity of structure to dissipate energy, structures can be designed for lower seismic loads. This factor has modified over time. In this thesis, the effect of the reduction in behavior factor on the response of two kinds of reinforced concrete systems were evaluated. Moment resisting frames and dual systems with different heights and regularity in plan, heve been design according to the behavior factor which is recommended in the 3rd edition of the Iranian codes of practice for seismic resistance design of buildings (Standard No. 2800). Drift and... 

Generally, nowadays, machine learning methods are used in many different areas for their superiority over other methods of prediction. Although being a tough task, stock market prediction with machine learning approaches is being spread due to satisfying results published ever yday. Machine learning methods usually use varied kinds of data ,including structured data such as market data, technical indicators and some fundamental data as well as unstructured one entailing text and graph data in order to enhance their predictability capacity. In this thesis we aimed to find out more about the importance and the contribution of structured data in prediction and we tried to attain a framework...