Sharif Digital Repository

Today, accidents are considered as one of the main causes of human mortality in the world. According to the World Health Organization, about 1.35 million people die in accidents each year, and 20 to 50 million people are injured because of accidents. In our country, about 17000 people are killed in traffic accidents annually. The mentioned statistics clarify the significance of paying attention to traffic accidents and identifying the factors that lead to them, as well as considering the strategies and policies for reducing accident rates. Due to the fundamental role of human factors in the occurrence of car accidents, the use of models that include the personality and attitude of drivers... 

This thesis is concerned with the robust control of multiple integrator systems, subjected to input saturation and external disturbance. Since nested saturation method has been demonstrated to be an effective tool for control of a chain of integrators, a feedback law using nested saturation is proposed. In order to deal with disturbance, an extended state observer is applied to nested saturation controller and a comprehensive analysis of stability is also presented. The existence of constant parameters in the proposed controller makes the design conservative which results in performance degradation in some cases at the presence of disturbance. To overcome this issue, an adaptive approach... 

The Iranian Nuclear waste management Company is responsible for the safe disposal of the low-level radioactive waste resulting from the various processes of nuclear fuel cycle and other radioactive-related activities. The safety assessment of waste disposal requires the measurement of transport parameters of radioactive nuclides in the soil around the disposal site. In this project, the transport parameters of cobalt nucleus in the Naeein disposal soil were measured using two static (batch) and dynamic (column experiment) methods. In the static method, the distribution coefficient was determined by performing batch adsorption experiments, and then the retardation factor for the soil disposal... 

Algorithms for online identification of parameters of a satellite’s moment of inertia tensor based on two methods (recursive least squares and Kalman Filter) is presented and compared with each other. It is assumed that the satellite actuators are three orthogonal reaction wheels. The only available sensor is a 3-axis rate gyro, which measures the angular velocity of satellite in body coordinate system. For validation of algorithms on earth, a similar identifier was designed for a satellite simulator. Due to difference in Dynamics of satellite and satellite simulator, capability of identifying center of gravity was added to algorithms. In order to account for friction in air bearing of... 

In present work, hydroxyapatite nano-rods are synthesized using a simple sol-gel method with calcium nitrate and potassium dihydrogenphosphate as calcium and phosphorus precursors respectively and ammonia was used for adjusting the pH=9. To obtain rod shape hydroxyapaite powder, multi wall carbon nanotubes were added to the solution, nHA powder was calcinated at 60 and 450 ℃. In second step, chitosan-gelatin/nanoHA solution were prepared by blending chitosan and gelatin in different concentrations with nanoHA powder, then the solution was freeze dried to maintain a composite scaffold. The prepared HA powder and bio-composite scaffold were characterized by X-ray diffraction (XRD), field... 

Although voltage control and stability issues are not new to the electricity industry, but nowadays, in most modern power systems, special attention has been paid to this issue. Once, only weak systems with long lines were involved in voltage instability, while today due to heavy loading, voltage stability is a serious concern even in developed networks. Over tim, with increasing demand for electricity and emergence of electricity market and economic constraints, power systems are more exposed to voltage instability and even voltage collapse. Therefore, reliable operation of the system in such circumstances requires evaluating voltage stability of the network at both stages of planning and... 

With the growing trend of IoT, especially in critical areas like health system and city management, and the expectations of even higher growth with the advent of 5G networks, the security and preserving of users' privacy in IoT has gained significant importance. Anomaly detection is one of the approaches to monitor IoT devices which enables the identification of anomalous behaviors. This anomalous behavior could indicate malware infection, physical malfunctions, or tampering.Deep learning has been a common approach for anomaly detection for the past few years. The solutions are mostly suggested in a special purpose manner and because they are based on a particular deep learning model, they... 

Nowadays, various policies are adopted by transportation managers and planners. These policies aim to improve system performance, reduce user costs, control and reduce air pollution, reduce noise pollution, and ultimately reduce congestion. A set of these policies in the form of transportation demand management is presented in the literature. A common way to find the effect of a policy on user behavior is to use questionnaires. Other causal inference models have been proposed in disciplines such as statistics, political science, marketing science, epidemiology, and psychology. The purpose of these models is to find the causal effect of an intervention (treatment) on a system. These studies... 

It is difficult and time-consuming to calculate the reaction rate directly. For turbulence modeling methods such as RANS or LES, various statistical methods are used to model turbulence-kinetics interactions. The purpose of this study is to implement the linear eddy model in CANTERA open source-code. This code instantly simulates one-dimensional, quasi-one-dimensional laminar flames with different chemical kinetics in which the effects of viscosity and molecular diffusion are implemented like a laminar flame. The effects of turbulence are simulated by a series of stochastic processes called triple maps. This research can provide a linear eddy model in different types of one-dimensional... 

As the number of patients waiting for receiving kidney transplantation increases all over the world, the average waiting time for a patient in queue rises too, and consequently, the rate of death goes beyond the accepted level. Also, unbalanced numbers of donors and patients with same blood type make the problem bolder. The aim of this research is to design a queuing model in which kidney could be transplanted from deceased donors to patients with different but compatible blood type (Cross-Transplantation) in order to make the average waiting time for patients with different blood type closer to each other. In other words, the transplant system is supposed to make a decision whether to... 

The blood pressure (BP) is one of the most vital signs to monitor human health. Hypertension is a major public health problem that is associated with morbidity and mortality. In the past decades, the number of people with hypertension disease has been increased. According to Ministry of Health, 54 percent of hypertensive patients are unaware of this health threat. Therefore, accurate and continuous measurement of BP is essential for its prevention and treatment. Traditional non-invasive methods of BP monitoring use an inflatable cuff, which causes discomfort due to occlusion of the artery and can not be used continuously. Numerous studies have attempted to present methods without using a... 

Dye-sensitized solar cells (DSSCs), belonging to the third-generation of photovoltaic cells, aim to mimic the process of photosynthesis for electricity generation. Titanium dioxide nanoparticles (TiO2) have been widely employed as photoanodes in DSSCs. However, the photoelectric conversion efficiency (PCE) of these solar cells is hindered by electron-hole recombination at the photoanode-electrolyte interface. To address this issue, two-dimensional graphitic carbon nitride (g-C3N4), synthesized from inexpensive urea, has been utilized to modify TiO2-based photoanodes. In this study, g-C3N4/TiO2 composite photoanodes with varying mass ratios were fabricated using an in-situ synthesis method.... 

Due to the increasing development of digital systems based on limited energy sources (i.e. battery), energy efficiency has become one of the most important concerns in the design of these systems. The use of multi-core architecture is an effective solution for the problem of reducing energy consumption. Hence using it in digital systems has become more common. In addition, enabling methods for reducing energy consumption on processor, helps in making energy more efficient. DVFS and DPM are the two major methods used for reducing dynamic and static energy consumption of processors. The using of multi-core architecture due to the higher chip density, results the static and dynamic energy... 

Due to violent and ferocious competition and global changes of new trends, directions and new ways of doing business, financial institutions grapple with new challenges and opportunities in today business. The advancement in technology, information and communication has forced banks and financial institutions into hard competition. In this new era technology, people as the customer are the elements on which the banks are concentrating them to manage customer relationship. In this complicated situation, Electronic customer relationship management (E-CRM) is seen applicatory and beneficial solution to improve customers‟ service, develop a profitable and long term relationship and retain... 

Today, almost all the Iranian mobile telecommunication companies should rely heavily on customer loyalty and customer retention as essential and vital tools to provide a competitive advantage in this competitive telecommunication world by offering value and upper hand service with respect to the existing demand in the Iranian market, hence these determinants arise the need for studying eCRM, Loyalty and Retention in order to achieve customer satisfaction in the Iranian mobile telecommunication field. 400 customers who use the Iranian mobile telecom operators’ services (Hamrah-e Avval, Irancell, and Talia) have been asked as respondents in this research. The study is based mainly on primary... 

The widespread use of the Android operating system has made it an attractive target for attackers. In the field of malware identification and mitigation, the use of machine learning methods has seen significant advancements due to their ability to identify unknown malware. One of these methods is graph-based techniques in constructing malware detection systems, which have achieved high success rates in identifying malware. However, machine learning methods suffer from the vulnerability of being misled by adversarial examples. One important aspect in both malware detection systems and adversarial attacks is the limitations imposed on software modification. Any changes made to the application... 

In this paper, the response of a concrete one-story frame with smart rebars under static lateral loading has been numerically studied, using Finite Element Method. The material used in this study is Shape Memory Alloy (SMA) which contains nickel and titanium elements. During lateral loading, rebars yield or concrete crushes in compression zone in some parts of the RC frames and also residual deflections are created in the structure. The SMA exhibits little residual strains under cycles of loading and unloading even after passing the yielding zone. In addition, SMAs have a good energy dissipation capacity that helps reduce damage while increasing structural capacity. In this study, SMA rebars... 

In this project, the photoelectrochemical properties of ZnO nanostructures modified by CdS and Graphene was studied. Firs, titanium foil was cut into rectangular shape with 1cm width and 3 cm length, cleaned by rinsing in acetone and ethanol and annealed at 4000C for an hour. As a result, a thin layer of titanium oxide was formed on Ti sheet. Then a layer of grapheme oxide was deposited on substrate using Electrophoretic deposition (EPD). After that, ZnO nanostructure was deposited on the TiO2 substrate using Electropulsation (EP) with 20 consecutive pulse followed by 3 minutes Electrodeposition (ED). Using SEM analysis, the morphology of ZnO was determined to be nanopetals in which the... 

Present work focuses on the influence of Heteroatom(s) on the bacisity of specific group of amines through the intramolecular hydrogen bonding. This group includes Aza-Crown Ethers specifically. We used Spartan and Gaussian packages to gain optimized structures for all compounds in order to explore the influence of the intramolecular hydrogen bonding on the bacisity of amines. All the gas phase optimizations and energy calculations were performed at the DFT/B3LYP/6-311++G(d,p) level of theory. The Hf/6-31+G(d,p) level was used for all single point calculations in the solution phase. As commonly used solvents in organic and biological reactions, the solution phase calculations were carried... 

Cache memory is one of the most important parts of the microprocessors. Caches improve performance by bringing data and instructions near the processors and decreasing the access time to data and instructions. But caches are also vulnerable to some kind of error called soft error. When an error happens in a cache, suddenly can propagate throughout the system and affect the integrity and reliability of the overall system. There are actually two types of errors in cache memories, permanent (hard) errors and transient (soft) errors. Previous studies have shown that about 92% of system reboots are initiated by soft-error occurring in cache memory. Soft-errors have two main sources, alpha...