Sharif Digital Repository

The problem of path simplification is an important problem in computer science. With the advances in navigation and geographical information based systems, simplification and data compression have gained considerable importance. The intends to find a path with less weight than the provided path while estimating the initial path with good accuracy and simplifying the storage and process cost of path information. This problem is not only useful in Geographical Information Systems, but it also has use cases in image processing and computer graphics and has been studied a lot in computational geometry. In this research, we introduce a simplification game that models the limited version of the... 

With the increasing importance of the sustainable development perspective, coupled evaluation of the environmental, economic, and functional performance of pavement maintenance programs needs to be considered. This task requires the use of data and models from different sources, which introduce uncertainty in the analysis. The use of probabilistic analysis may allow decision-makers to reach more realistic conclusions. To this end, all phases of the pavement life cycle, including material production, construction, use, and salvage at the end of life, should be considered. The effect of pavement-vehicle interaction (PVI) in the operation phase has received less attention from researchers. In... 

While Cloud providers face problems during providing services to their clients, such as lack of resources or increasing idle resources in low workload; they can share their resources with other providers by participating in Cloud Federations, and take advantage of Cloud Computing benefits like high scalability and resource extension. Moreover collaborating Cloud Federations expands Geographical area of providers. The Resource Allocation Problem has been considered in many researches, but in fields like Cloud environment and Federated Clouds it comes with complications. This thesis analyzes an optimized mechanism based on game theoretic approach for Resource Allocation Problem in Federated... 

The rate of cesarean section delivery in Iran is high and during the past 14 years, leading up to 2014, kept rising. In this regard, decreasing cesarean section rate was targeted through the healthcare reform plan, which was offered by Ministry of Health and Medical Education. This plan kicked off on May4, 2014. One of the most important proceedings of this plan was making natural childbirth to be free in all hospitals, which are under the auspices of the medical universities. According to healthcare utilization models, lower prices of healthcare services, more health centers and more accessibility to them, increase the probability of using health care services. Current study evaluated the... 

A wide range of field devices, including Intelligent Electronic Devices (IEDs) and Remote Terminal Units (RTUs), are used in Industrial Control Systems (ICSs). These devices are embedded systems that are responsible for protecting the power system devices against faults and damage by controlling circuit breakers. Disruptions in command and control can result in accidents and harm. Due to their physical accessibility and the possibility of backdoors, blackout attacks may be designed and implemented on these devices in a manner similar to what has occurred in many countries in recent year.Many vulnerabilities have been reported for Real-Time Operating System (RTOS), firmware, and software of... 

Traffic flow modeling on different levels was always the topic of many studies. In this regard, many researchers have tried to eliminate traffic problems by developing precise models. Therefore, in this study and in its two major parts, we developed two models: one macroscopic and one microscopic. Like previous studies, the main purpose here was the development of traffic flow models that have better precision and give more information about the mechanism behind the traffic phenomena. Our focus was on the free spaces in front of drivers which were considered in a macroscopic traffic flow model and resulting microscopic traffic flow model.First part, addresses the first-order extension of the... 

IC221M is a cast Ni3AI-based intermetallic alloy which chemical composition bases on Ni- 8Al-8Cr-1.5Mo-1Zr-O.OIB %wt. Because of high strength, good high temperature oxidation, carburization and creep resistance as mechanical and physical properties, IC221M has got good attention in aeronautical, military and steel production industries nowadays. The best service temperature range is 600-800°C and melting starts at II 70°C. Since 1993 according to broad range of researches and applications, ASTM standardized it at Al002-99 and from that time researchers try to replace steel with IC221M. %80 volume of microstructure in this alloy consisted of brittle y' and remain are y and low... 

Wireless sensor networks (WSNs) are composed of many independent spatially-distributed sensor nodes where communicate their information acquired from environment to shape a uniform view of their managed scope. Using WSNs in places which human can hardly attend uninterruptedly, as well as constraints such as low power consumption, low price, small size, and limited radio range, are the biggest challenges for researchers and WSN designers. Supplying security is yet another common challenge of using these networks. The beginning chapters of this dissertation introduce the most important security mechanisms in WSNs, that is, key management and cryptography. Since each application has its own... 

With the increasing tendency of consumers to purchase from online stores and the remarkable growth of this industry in recent years, timely and cost-efficient delivery of goods to the final customer has become one of its major challenges. Accordingly, last-mile delivery has attracted significant attention from both researchers and practitioners. This study addresses a vehicle routing problem that considers customers’ ability to pick up their orders from selected centers and their possible presence at different locations within the planning horizon. This thesis aims to enhance customer satisfaction and reduce distribution costs by employing two innovative vehicle routing approaches. The first... 

In this research, the mechanical section of a reduced-scale hybrid vehicle simulator was designed and fabricated. In order to scale down the vehicle dynamics, a method based on dimensional analysis was proposed. An internal combustion engine and an electric motor were selected as power sources and then, scaling was performed, according to the specifications of the combustion engine. Afterwards, the power transmission system was designed first in concept and then in more detail. Finally, the design was manufactured and assembled. The study was made in conjunction with another study responsible for the controlling section of the work, conducted by Safabakhsh The sponsor of these two researches... 

In this study, the properties of super-hydrophobic Ni coating on carbon steel including wetting behavior and corrosion resistance of Nickel coatings deposited on the steel substrate were investigated. For this purpose, Nickel coatings deposited by electrodeposition method in deferent current density (10,20,30,50, 70 mA /cm2) in bath containing 1.5 mol of ethylene de-ammonium de-chloride, 0.5 mol H3BO3, 1 mol Nicl2.6H2o and then immersed in a bath containing 0.01 mol per liter myristic acid and ethanol for 24 hours and then placed in the room temperature for 14 days. Deferent tests were used for characterization, wettability properties, corrosion behavior and morphology of Ni coatings. The... 

Population growth and the escalating use of electric devices have led to a surge in electricity demand. However, the construction of adequate infrastructure to meet this additional demand is highly expensive. To address this issue that sometimes causes power outages, dynamic pricing for electricity, a demand management technique, has gained significant importance. By employing this method, prices can be adjusted on an hourly basis, enabling consumers to regulate their consumption in response to these price fluctuations. The prices can be determined based on different objective functions. This research aims to develop a comprehensive framework for determining the optimal hourly electricity... 

Digital computers, comprising universal logic gates, are tremendously versatile. This versatility associated with the increasing integrability of digital electronics due to Moore’s law has left nearly no room for analog computers in the last few decades. However, in the case of some specific problems such as modeling complex and nonlinear systems or pro-cessing large amounts of data, computation time and power is still a serious restriction of digital computing. Optical phenomena are fast enough and offer novel approaches to overcome the mentioned restrictions about the system speed and power consumption. Therefore, optical structures make possible to perform ultra-fast spatial analog... 

In the presented research, feasibility of producing hybrid nano-composite on the surface of Al1050 with TiO2 (~15 nm) and Graphite (~100 μm) reinforcement particles via Friction Stir Processing (FSP) has been investigated. 1.93%, 1.68% and 1.44% are the weight percentage of added reinforcement particles in the nano-composite. Rotational and travelling speeds (and their ratio, ω/v) and volume fraction of the embedded reinforcement particles, mentioned as variable parameters in this research. Despite, effect of these parameters on the microstructural evolution and mechanical properties such as strength, hardness and wear, were studied. Results in the ratio of Gr/TiO2 = 1/3, revealed that by... 

The low female labor force participation rate in the Iranian labor market relative to the global average and even to countries that do not differ significantly from the socio-economic characteristics of our country is one of the important questions of the Iranian labor market. In this study, we seek to answer the question of whether the economic participation rate of married women will increase if the gender gaps in wages, job findings and job losses among women and men are eliminated in the Iranian labor market. To answer this question using household expenditure and income data and labor force data, we show that between the two categories of occupations, in terms of the share of women's...