Sharif Digital Repository

The recent advances in communications and processing technologies have paved the way for a new business model in IT industry. In this new model, frequently called “software as a service” or in short SAAS, software is hosted on servers operated by a software vendor instead of customers and all required transactions take place through the network, especially through World Wide Web. There are several differences between traditional business models and SAAS, including pricing and revenue model. Given the fact that vendor’s can monitor the customer usage, new and more complicated price structures such as usage-based pricing is possible, In this new business model. Although this pricing structure... 

Since 1980s the electricity market has been gradually evolving from a monopoly market into a liberalized one for encouraging competition and improving efficiency. This brings the opportunity for generation companies (Gencos) to make more profits while embracing more risks of not being dispatched. Therefore, it has become a core interest for the Gencos to develop optimal bidding strategies to maximize the profits and minimize the risks while participating in such a competitive market. Error of determining day-ahead electricity price is one of the sources of the risk. Energy price has a high impact on bidding strategy optimization process. So it should be determined with low error which is not... 

The multi-facility location-allocation problem is concerned with locating m facilities in the Euclidian plane and allocating n customers to them at minimum total cost. In this work, we focus on a probabilistic version of the problem, in which the locations of the customers and their arrivals are probabilistically distributed. We first formulate the problem as a continuous location-allocation problem. Then, we give an approximated discrete model in which facilities can be located on a set of candidate points. The proposed model has two objective functions which can be calculated only through simulation. Considering the NP-hard nature of the problem and the functions’ unique properties, we use... 

Recent developments in space industry and the great tendency for definition of efficient, precise and low cost missions are the main reasons for the growing interest in satellites formation flight. Regarding the aforementioned, the study of the multiple satellite control methods is the subject of the present project. In this project, the governing equations of motion of satellite formation flight are developed. Based on this development, it is shown that the satellite linear equations of motion like many other linear system presentations, can not sufficiently model the real system. Therefore, some of the most famous uncertainties in space dynamics such as semimajor axis and eccentricity... 

Trasmission system is one of the most important parts of the power system which not only creates an interface between generation and distribution section, but also provides a reliable and non-descriminated environment between them. In recent years, restructuring is introduced in many countries of the world. The competition is begun in generation section while, the transmission section was remained monopoly. Private investors don't have enough incentive to invest in this section, because, the presence of uncertainties have made decision making hard for them and increased the investment risk. On the other hand, with increase in consumption and generation, need to invest in this section seems... 

The process of deregulation that has involved electricity many markets has introduced several new interesting research topics in power system area. This thesis addresses one of the most fascinating issues among them: the study of distributed generation both renewable and conventional integration in distribution networks. From the distribution network operator (DNO)'s point of view, it is of interest to develop a comprehensive methodology which considers various distributed generation technologies as an option for supplying the demand in distribution networks. In this thesis, the planning problem has been multi-objectively modeled. This will help the planner in decision making while knowing... 

Increasing the fuel cost and concerns about pollutions have facilitated the use of renewable energies. Wind power as a renewable energy has been considered as a good representative for conventional resources of electrical energy. The biggest obstacles for efficient use of the wind energy are changeability and uncontrollability in wind farm generation and to be far from the demand center. Also, conventional approaches cannot be applied to analyze the effects of this energy on power system. With increment in the penetration of the wind energy in power system, the necessity of considering its effects, especially large scale wind farm, in transmission expansion planning (TEP) studies is... 

Most of the researches on project planning and scheduling have supposed that there is a complete and fixed information about the activities duration and amount of resources needed for project, but in reality we face lots of uncertainty in activities duration and required resources. In previous researches there are some cases which lead to more than one schedule for project, but in most of them they offer no solution for choosing between the schedules. In this project we are trying to make a nonlinear model of project environment by using Weibull distribution as activities duration and then we determine the input information by using the methods of probability encoding in decision analysis.... 

Facility Layout Problem is one of the classic problems with the goal of arranging facilities with respect to the objective function and it’s been the subject of many researches for many years. By progressive development of industrial units in recent years and the lack of space especially in major cities, using multi-floor buildings can be a suitable solution. In literature, a few researches on this kind of layout problems are done. Maybe the main reason is difficulties of modeling. In this problem, with regard to objective function, interior and between floors flow and some predefined constraints, a suitable floor and place for each facility or department is determined. On the other hand, in... 

Increasing demand in power systems necessitates the Generation Expansion Planning (GEP) which is to determine the type, size, and location of new generating units in a planning horizon. The final solution of GEP is based on the minimum cost and/or optimum reliability taking into account various constraints such as capacity of units and lines, operating constraints, and budget restrictions. This paper presents a model based on scenarios for generation expansion planning and units retirement decision. The proposed model could be used by vertically integrated utilities as well as the ISOs in electricity markets to obtain generation expansion schemes. In this approach, uncertainty of units are... 

As a matter of fact, power systems are always faced with a variety of uncertainties. These uncertainties change system parameters in an unwanted manner which may deteriorate the system security and reliability. For instance, a transmission line which is designed for a certain capacity may be suffered as a result of load increment and consequently may influence the normal operation of other network elements. In recent years, as a result of environmental considerations and especially after the oil shock at 1973 which caused the the energy prices to increase unprecedentedly, the human has taken more attention to renewable energies exploitation. Theses energies have a fluctuating nature and are... 

Intraction in multi input multi output (MIMO) system makes control of these systems difficult.There are two ways to control such systems; Centralized and Decentralized control. One way in which a centralized controller is designed is using a precompensator. With application of the pre-compensator, the MIMO sytem is decoupled into several SISO systems and one can control these seperatly. Almost all previews methods for the design of pre-compensator assume that the model of the plant containsno uncertainties.In this thesis a new method is proposed which takes into account model uncertaintes in the design of the pre-compensator.The form of the uncertainties considred an interval-parametric  

Power distribution network planning and related optimization is an interesting research subject and many papers have been published on this topic. Distribution network planning started in developed countries. Therefore network models are based on reliable network data, educated crew and low interest rate. Nowadays, Iranian engineers and researches try to use their research result for solving network optimization problems but sometimes the result of optimization is not achievable in reality. In current thesis, modeling approaches developed by previous researchers were compared and the effect of model simplification was evaluated. This evaluation was based on data gathered from local power... 

Travel demand estimation is a complicated process as travel demand is highly influenced by uncertainties. These uncertainties can be analyzed in two levels: aggregate and disaggregate. Models in aggregate level are usually influenced by uncertainties in data insufficiency in some regions of data space because of non uniform distribution of input data. Uncertainties embedded in travelers’ perceptions of some influential variables on demand estimation (such as travel time) moreover affect these models. An expert-guided algorithm to incorporate expert knowledge into adaptive network-based fuzzy inference system for compensating data insufficiency and considering uncertainties inherent in... 

In this research, a new Bayesian method for constructing confidence intervals on the parameters of any continuous distribution is first developed. The main idea behind developing this method is to model uncertainty. As an application of the proposed methodology, confidence intervals for the two parameters of the Weibull distribution along with their joint confidence interval are then derived in which data can be of type I censored data, type II censored data or uncensored. The new confidence intervals are next compared to other existing exact confidence intervals in the literature and shown to have better performances. Furthermore, we show the lengths of the existing exact confidence... 

The purpose of introducing this thesis is to review the difference between Standard Quantum mechanics and Bohmian Quantum mechanics. The aim of this dissertation is not only to contrast these theories with respect to formulation, but also to briefly review their historical, philosophical and sociological aspects. This dissertation consists of two main sections. The first section is about reviewing the emergence profile of these theories and the formation of each theory along its historical path. In addition some beliefs about the founders of these theories and the impact of their beliefs on the evolution of their theories are put forward. As a complement to the above, the prevailing social... 

Quantum Mechanics, as the most famous physical theory was founded about 85 years ago; but still there are a lot of debates about its interpretation. In this work, we review some basic concepts of Quantum Mechanics in form of questions about uncertainty principle, measurement problem and complementarily. We also review Bell inequality which has great philosophical and recently technological results. Bell derived his inequality regardless of modeling the measuring apparatus; we show, by take a realistic model for measuring apparatus, Bell inequality would be deduced. Finally we review a mathematical language which was used to show the duality of wave and particle. Quantum... 

Concerning the variety of existing buildings and the diversity in the factors which affect the behaviors of structures, subjected to earthquakes, presenting a definite method for studying their seismic vulnerabilities has not been realized yet. Selecting a method which covers all mentioned necessities is extremely wide and complex. From one side, the capacity of structural system should be determined based on its strength and deformability. On the other hand, the nonlinear behavior of structure should be predicted by selecting the probable effects of earthquake on the region. Then, the force or acceleration which causes damage of structure's components, and the whole structural system,... 

Transportation networks are considered as complex systems, and in many cases they behave in such an irregular and unexpected manner. Such complexities cause problems in studying the behavior of these systems. An example of such complexities is chaos in the network flows. On the other hand, the behavior of these networks is highly affected by the incidents like accidents and bad weather. Such events affect the level of service and travel time reliability of the networks. In this research, a dynamical approach to traffic assignment has been chosen to model chaos and uncertainties in the network. By using this approach for modeling flow evolution, edge of chaos and uncertainty in supply and...