Sharif Digital Repository

This thesis analyses the relationship between performance and capital structure of listed companies in the Tehran stock exchange. For examining this relationship, we use trade-off theory. This theory states that using debt comes with some benefits and costs for the company. If this theory holds true, we expect that in a low debt capital structure, as a result of benefits of using debt surpasses the costs of it, the relationship between debt and performance should be positive and in a high debt capital structure, as a result of costs of using debt surpasses the benefits of it, using more debt should have negative relationship with performance. For examining this relationship, we first gather... 

This research investigates the impact of Bitcoin and cryptocurrency news along with macroeconomic and financial indicators, on Bitcoin price fluctuations for two years (May 2016-2018). The reason for this examination is due to high variations of Bitcoin price in the late 2017 and beginning of 2018, while academic research focusing on Bitcoin price are mostly conducted before 2017. Findings show that the number of news with positive and negative contexts, and news related to cryptocurrency technology have a direct relationship with Bitcoin price change. The other result shows that among news concentrated on Bitcoin, the most effective is regarding adverse incidents, famous people concerns and... 

Over the past two decades, in developed countries, public-private partnerships have been used as a mechanism to provide the required infrastructure by using private sector capacity. Risk management is the most critical factor in achieving optimal "value for money" in this type of project. In Iran, this is still far from its maturity and the growing trend of adopting this method and the vacuum of its academic literature in the country, necessitate such research. This study has been written to solve this problem due to the lack of risk management framework in the contracts of Tehran Municipality's Partnerships Organization. This dissertation covers three stages of risk management, which... 

In the contemporary world, especially after the financial crisis, the importance of financial flow and working capital management for companies has become more important than ever. There have been various ways to meet the financial needs of companies in the past. Financing methods such as giving capital from investors and receiving loan, from the past, to new methods such as supply chain financing, which have been the major part of financing researches since 2005.Conversely, companies interact together to meet the needs of end customers and thus form a supply chain in which the product / service of each company, input and raw material of the company Forms the next. This chain of... 

In Private Equity funds, the manager (known as general partner) collects funds from the investors (known as limited partners) and invests them over a certain time horizon. Assuming that both parties seek to maximize their interests, a situation arises in which the manager does not consider the best interests of the investors. The manager's compensation package is one of the important parts of corporate governance, which consists of four components: management fee, performance based fees (or carried interest), hurdle rate and proceeds distribution method. In this research, first by conducting a semi-structured interview with 15 experts in the PE ecosystem and publishing a questionnaire, the... 

This project presents appropriate strategies for HIV infection treatment. In order to close the presented strategy to real treatment regimen, appropriate parameters are selected for the HIV infection model, real outputs are considered for the system, and three widely used drugs (one PI: ritonavir (RDV), two RTIs: lamivudine (3TC) and zidovudine (ZDV)) are used to design a drug regimen. A Luenberger-like nonlinear observer (LNO) is also designed for estimation of unmeasurable states. In order to minimize the side effects of drug regimen, the concentration of ZDV is fixed at a minimum value at all time because this drug has a greater side effects than other drugs and the parameters of... 

Conjugated linoleic acid (CLA), a mixture of positional and geometrical isomers of linoleic acid with conjugated double bonds, has gained considerable attention because of its anticarcinogenic and obesity treatment properties. The most biologically active CLA isomers are 9c, 11t-18:2 and 10t, 12c-18:2. The aim of this study is to separate and purify the two essential isomers via enzymatic method by Candida rugosa lipase and chemical method by urea crystallization and also optimization of reaction conditions in order to better separation. For enzymatic purification, L-menthol and Lauryl alcohol were used separately. Optimization of reaction conditions by enzyme content, time and the ratio of... 

Many researches have been made on super hydrophobic and photocatalyst nano coatings in the last decades as a solution to some environmental issues. Among all semiconductors chosen for this property, titanium dioxide is often used because of it's low cost, ease of accessibility and stability in different chemical circumstances to break up organic pollutions. Mixing this property of TiO2 with hydrophobic manner of SiO2 causes a superhydrophobe & photocatalyst nano coating. Doping TiO2 with another semiconductor may also improve photocatalytic behavior of coating by increasing surface area of reaction or decreasing the band-gap.In this research TiO2-SiO2 hybrid nano coating is made via... 

Steganography is method for communicating confidential information through a non-trustworth in way which hides the existence of communication. For improving the security of steganography statistical detectability must decrease as such as possible. Despite the fact, that the quality of the relation between statistical detectability and amount of distortion engendered by embedding is still an open problem, problem of detectability reduces to problem of management of pixel embedding in order to minimization of distortion. As in wet paper coding methods, an optimum (or approximately optimum) algorithm proportioned to Pixel-cost has been offered, the current problem of steganography is to find... 

In recent years, Intelligent Transportation Systems (ITS) have received special attentions both in research and in commercial areas. Increased infrastructure facilities, like surveillance cameras, has made this concept even more attainable than before. In this respect, the ability to automatically extract information from traffic images, as one of the key inputs of ITSs, is of great importance. With an increased number of surveillance cameras and the need for more accurate information regarding the road users and their interactions, in order to better city traffic management, building and repairing roads, trip time estimation, number of people per roads estimation and etc, using human... 

In today's world we are dealing with many devices and processes with the goal of efficiency and performance improvement. In many processes particularly chemical ones, the goal is to control the output according to its constraints in the way that the performance is economically efficient, such as reducing energy consumption and energy loss and increasing efficiency. In order to control a process with economical goals, an economical cost function is used and after determination of optimal values a controller is used to guide the process so can achieve them. Model predictive control (MPC) is very common in this economic control Due to advantages such as considering the problem constraints. In... 

With the advent of technology, small in size sensors, memory, speeding up the processor and lowering the cost, it is possible to build an embedded camera system. The goal of this project is to design and build an embedded camera system so it can execute any set of necessary algorithms as depending on the application. In this project, two models of embedded camera systems have been presented as an integrated system and a system with independent units. To design the integrated embedded system, ZYNQ processor is used and two structures are presented in the form of hardware-software and hardware design. In hardware-software design, image processing operations are done by software and in hardware... 

Smartphone sensors like accelerometer, gyroscope and magnetometer are very common nowadays. This gives us the opportunity for sensor-based activity recognition. This thesis's goal is to collect data from different smartphone sensors and then extract hand-crafted features and classify them using machine learning algorithms. Metro, bus, taxi, bicycle, running, upstairs, walking and standing are studied activities in this thesis. All above steps are covered in this research, later we want to present an activity recognition model and then test it through a web server, after that, we modify the model by proposing to change learning coefficient to gain better accuracy. Finally, an Android app was... 

The importance and vitality of focusing on sustainable transition and reducing carbon dioxide emissions are clear to everyone today. However, until recently, the impact of digitization as a major global trend involving the application of digital technologies to change and optimize various elements of business, society, and daily life on the environment and carbon dioxide emissions has been underestimated. Despite the growing amount of research in this field, according to current studies, the connection between digitization and carbon dioxide emissions is not clear. To achieve environmental and sustainable development goals, fossil fuel consumption and greenhouse gas (GHG) emissions must be... 

In this study, the influence of eutectic modification, grain refining and cooling rate on amount of shrinkage porosity in aluminium A356 alloy were investigated. Modification process for changing the morphology of eutectic silicon from needle like to fibrous like, use in aluminium – silicon alloys. This process often leads to increasing porosity in melt and affect harmfully on mechanical properties. For studying shrinkage porosity, the melt degassed completely to minimizing amount of gas in the melt. For modification, strontium in Al-10Sr master alloy and sodium in NaF salt used and for grain refining Al-10Ti and Al-5Ti-1B master alloys used. To study the effect of cooling rate, three mold...