Sharif Digital Repository

The so-called “Fast Downward” is a successful heuristic planner. This planner extracts informative data structures during planning. A number of efforts have been made to detect some constraints for guiding search toward the goal, in the hope to speed up the planning process. These constraints usually result in a number of sub-goals and determining their proper ordering. These sub-goals are called landmarks, which must be true at some point in every valid solution plan. Landmarks can be used to decompose a given planning task into several smaller sub-tasks. In this dissertation a new method is proposed to extracts landmark and recognizes their ordering based on fast downward basic data... 

In the recent years, there is a worldwide wave of considerable changes in power industries, including the operation of distribution networks. Deregulation, open market, alternative and local energy sources, new energy conversion technologies and other future development of electrical power systems must pursue different goals. Also growth in the demand and change in load patterns may create major bottlenecks in the delivery of electric energy. This would cause distribution system stress.Furthermore, in competitive electricity markets, operators determine the electricity price for specific intervals during a day, taking into account various economical and operational factors. Traditionally, a... 

Planning is one of the most important branches of artificial intelligence. The goal of planning is automated production of sequence of actions (plans) for some specified tasks. However the computation done by planners is very time consuming and complicated. Distributing computation is one solution to overcome such difficulties. Distribution divides the load of process between a number of agents and increases robustness. The purpose of this project is to reduce the computational overhead of planning by the means of distributing the planning process between a numbers of planners. In the proposed method, we first divide a classical planning problem to two separate subproblems by decomposition... 

The most common procedure of operating theatre scheduling in hospitals consists of two major steps called assignment and sequencing. In the first step, patients are assigned to a so called block (part of an operating room time in a specific day). The sequencing step is usually executed a day before the pre-defined day. In this step, the head nurse makes a sequence of the operations while she consults with the relating surgeons and considers all of the conditions and then the patients are informed about their operation time. Although the head nurse does not have a biased look, surgeons usually believe that the schedule is unfair to them. Moreover, the schedule is prepared through trial and... 

In an era of tight budgets, productivity measurement is a managerial concern. To analyze productivity precisely, real-time productivity measurement through an appropriate IT infrastructure is needed. Enterprise Resource Planning (ERP) is an IT tool which integrates all organizational units and facilitates real-time productivity measurement. To measure productivity levels continuously through an ERP system, organizational structure must be coherent.The main aim of this research is to propose coherent structures for a healthcare organization, as an introduction to facilitate real-time productivity measurement. To accomplish this purpose, present structure of the selected healthcare... 

Interceptor is a blade installed on planing hull transom, and it helps the planing performance by making an stagnation point on aft part of the hull thus generating a lift force and reducing the planing trim. In the present study a numerical modeling of a planing hull in still water has been made and the effect of an interceptor in the numerical model has been studied. Then by validating the model with and without the interceptor through experimental model testing, it has been used for modeling a planing hull in waves with an interceptor. The numerical modeling has been made using 2DOF analysis in Ansys-CFX and the experimental model tests have been done in Mechanical department of Sharif... 

In this research, effect process TOC in MRP system have been studied,therefore, first the hypothesis in TOC process and MRP system have been studied and generated. Afterward, whit the use of library and sydies the research guestions have been compiled. The society under studyis an aluminium oasts manufacturing daycust tabriz company. For surveying the memtioned company, samed documents hase been studied. After gathering all information and documents, and analyzing them, the result has been revealed. Therefore the effect of TOC and MRP process an production system has been comeout. At present situation, the mast crucial factors for suruival and compdtetion are ones couse the reduction of the... 

The concept of smart grid to realize the triple goals of economy, reliability and environmental improvements has taken advantage of modern equipment and new structures. Beside these goals smart grids seek to increase the level of penetration of renewable resources for environmental improvement. On the other hand, increase in dispersed products and problems resulting from increasing these non-dispatchable resources thus led the researches to design a new structure called microgrid. Microgrid improves the reliability of these resources and facilities their uses. But uncertainty and intermittency in producing renewable energy resources are among the main challenges facing these microgrids.... 

Operating rooms has always been considered as one of the most expensive, yet most profitable part of a hospital. Since many units in the hospitals are related to the operating room, improving efficiency in the operating room will result in increased efficiency in other units, so offering proper solutions in this area is very important. Suitable Planning and scheduling has a great impact on increasing the level of service and efficiency of the hospital. in this thesis, a mixed integer programming model for scheduling weekly elective patients in the surgical theater with the objective of maximizing the number of elective patients for the surgery and also the workload of the operating room... 

Nowadays, due to the increasing importance and penetration of microgrids, solving the microgrid optimal sizing problem has become more important. The current utility grid and conventional energy sources are mainly ac, however, increasing rate of the replacement of the ac load with dc load lead to a more efficient dc system. So choosing the optimal type of microgrid as a way to increase efficiency of these systems would be a serious issue. This thesis establishes a planning model which finds the optimal size and type of a microgrid to minimize total cost. Total cost includes investment, operation and reliability cost of the microgrid. Sizes of DGs, converters and transformer linking the... 

During the recent past, due to the increase of electrical energy demand and governmental resources constraints in producing additional capacity in generation, transmission and distribution, privatization and restructuring in electrical industry has been considered. In most of the countries, different parts of electrical industry like generation, transmission and distribution have been separated in order to create competition. Considering these changes, environmental issues, energy growth, investment of private equity in energy generation units and difficulties of transmission lines expansion, DG units have been used in power systems. Moreover, reduction in need of transmission and... 

Renewable resources, because of their compatibility with the environment, accessibility, and low cost of operation, have become the center of unprecedented attention. Since the output of these resources cannot be predicted accurately, they are usually implemented in microgrids with conventional generating units and energy storage systems.Furthermore, distribution networks are integral parts of power systems, and many studies have been conducted in order to improve them. Because of high investment and operation costs of distribution networks and environmental concerns, it is necessary to conduct meticulous economic studies so that with proper investments, profitable opportunities are provided... 

Planning is a process to reach organizational goals, which many organizations can implement it to follow their desired outputs on the considered horizon with optimal costs under existing constraints and minimum control effort. Model Predictive Control (MPC) approach is considered as a planning approach based on forecasting model which contains three parts including objective function, constraints and forecasting model. The aim of using Model Predictive Control is to find specific numbers of current and future inputs on the determined horizon under existing constraints to reach the desired outputs of a dynamic system with minimum control effort. In order to deal with uncertain parameters of... 

Proliferation of distributed energy resources and the developing of smart grid concepts are of a great importance. This, however, influences the future of power systems and necessitates more studies in order to cope with the changes. In this regard, uncontrollability issues are arised by introducing the renewable energy resources in the power systems. To address this issue, energy storage systems are used to mitigate negative consequences of using renewable energy resources. Accordingly, in this thesis, a new framework for determining the capacity and location of the energy storage systems is proposed. In addition, reconfiguration of distribution network is also concerned in order to... 

Electricity is one of the most important kinds of energy and also one of essential needs of humans for maintaining their life. Due to growth of costumer’s load and In order for delivering high reliable power to the consumers, the structure of the power grid must be expanded and/or demand side management policies like demand response programs must be taken into consideration. One of the most important and less-focused aspects of power grid expansion planning is, distribution system expansion planning. Distribution system expansion planning (DSEP) is an important task of electric distribution companies and operators in order to appropriately supply their customers load with the minimum cost... 

Reinforcement learning is one of the most well-known learning paradigms in biological agents and one of the most used ones for solving plenty of problems. One of the reasons for this widespread use is the low demand for supervising signals. However, the sparsity of the reward signal causes increasing in sample complexity that needs for learning new tasks. This issue makes trouble in multi-task settings, specifically.One of the most promising approaches to learning new tasks by limited interaction with the environment is meta reinforcement learning. An approach in which fast adaption becomes possible by limiting hypothesis space and creating inductive biases by learning meta parameters.... 

Sustainable energy supply and preservation of the environment have become the main motivations to integrate more renewable energy sources in electrical networks. However, with an increasing penetration of renewable energy sources in the modern electrical grids, new challenging issues arise regarding the power system planning, operation, control and protection. An important technical issue is the difficulty in achieving the frequency stability of these systems, as the renewables are often operated at the maximum power point, resulting in less generation units that provide reserve power. Moreover, the rotational inertia of the system is reduced due to the decoupling of the renewable energy...