Sharif Digital Repository

Common Object Request Broker Architecture (CORBA) is a standard for hybrid applications that is designed and supported by Object Management Group (OMG). This standard defines protocols and Relational Data Model Objects / Services which can be connected into heterogeneous software (written in different languages). So we can use CORBA to share the distributed object platform, without worrying about where they are located or who has designed them. CORBA can package the codes (in some programming languages) and add the packaging information, such as the ability to execute the codes and how to implement them. So this package or object code can execute some other programs or CORBA objects that... 

In recent years, there have been many efforts for distributing a big and complex duty among some agents in order to do it more simply. Large number of these methods are in area called distributed systems, where several different agents start to work together to do a difficult or complex duty which each of them cannot do it lonely. Combination of distributed systems and artificial intelligence is known as distributed artificial intelligence.
One of the theories that has received attention recently, is called Embodiment. According this theory, in cooperation of a set of agents for performing particular task, expertise might not be integrated in a centralized controller, rather it gradually... 

Since traffic lights are the only mechanized system at street level, their operation mode affects traffic congestion. Since traffic lights organize vehicles at crossways, the target of traffic light smartification is to reduce waiting time based on the density of traffic flows. There are many topics that work in this field to recognize traffic before making any decision based on traffic. Hence, if it is possible to introduce an algorithm for change static timing and predetermined timing of the traffic lights, it can affect the density of traffic at the large scale. This dissertation introduces an algorithm to reduce traffic congestion using traffic lights and correct timing. In this case,... 

Residential demand response is an appropriate control tool for improving system reliability. This project intends to establish a model to activate residential demand response to improve distribution network reliability. Two centralized and decentralized models are proposed. The models aim at minimizing the damage cost imposed by load curtailments following unexpected events. In the models, it is supposed that distribution system operator (DSO) and responsive customers already signed a contract authorizing the DSO alters the operation of responsive appliances whenever system reliability is jeopardized. In centralized framework, Responsive customers deliver the technical data of their... 

Nowadays network marketing has promoted marketing, sale and customer relationship altogether. On the other hand, due to the growth of internet, network marketing has become a powerful and attractive channel that can be utilized alongside the other traditional channel. Pricing and network marketing structure influences on distribution system coordination and networker motivation in network marketing. This thesis provides a framework to study the integration of network marketing with retailers in a dual channel distribution system and provide the pattern for determining the different variables of distribution systems, including of product price in diverse channels, commission payment to... 

Power distribution systems have been traditionally operated as passive networks which consume electric power supplied by the transmission grid. Increasing utilization of wind energy in distribution systems, notably wind energy, is changing the way distribution sys-tems are operated. The distribution system operators (DSO) would operate the available wind power for reducing the power purchased from the wholesale market. However, high penetration of wind energy in distribution systems would require advanced operation mod-els and additional flexibility in system to offset the variability and uncertainty associated with wind energy. In addition, wind availability often does not positively... 

Approximate Agreement (AA) is one of the most important issues in distributed networks in which non-faulty processes execute a voting algorithm to reach the values that are very close to each other. AA for Partially Connected Networks (PCNs) is very limited because a node may not have a complete view of the whole network which makes it difficult to reach the convergence. This research proposes a convergent Fuzzy algorithm for synchronous distributed networks in the presence of faulty or Byzantine processes. When each node receives a new value from its neighbors,it runs the convergent Fuzzy algorithm. If the received value is not in the expected range of values, the processor can discard the... 

Power distribution systems are experiencing restructuring owning to the increasing trend of integrating renewable energy sources as well as privatization in the network. In this regard, the dependence of power generation by renewable energy sources on meteorological characteristics would challenge the conventional procedures of operating the system. Respectively, while the expansion of renewable energy sources would facilitate supplying the demand loads locally; the issues associated with the uncertainty and variability of power generation by these units should be addressed in future operational schemes of distribution systems. This condition has resulted in the development of the... 

With the increase of renewable energy generation in power systems, the flexibility of power systems has been challenged and the high potential of resources in active distribution systems for providing flexibility has been noticed by system operators and planners to help system flexibility. In this regard, these resources can participate in the Flexible Ramp Product market which is a new product that is defined for this purpose. In this work, the management of these resources has been modeled in an active distribution system for participating in this market by considering the network constraints, the uncertainty of renewable generation and forecasted prices of products in DA and RT markets,... 

One of the topics that has been given great consideration after restructuring and smart grid emergence, is loss management. This subject is specifically important in distribution systems, which have been reported to have 70% of the total loss in power systems. In this thesis, distribution loss is studied and its affecting factors are analyzed. Then loss optimization and loss cost allocation to distribution consumers are studeid. In order to acheive these two goals, it is neccessary for the distribution system to have the capabilities of a smart grid. The subjectof distribution reconfiguration is duiscussed as one of the loss reduction methods. Traditional reconfiguration problem trend... 

Focusing on developing the EEPS (Energy Electric and Power System) based on the SG (Smart Grid) infrastructure to achieve implementation of EI (Energy Internet) ultimately, in order to analyze and manage the energy/power consumption, requires a robust embedded EMS (Energy Management System) to implement real-time LF (Load Forecasting), prevent the power waste and realize consumption management which eventually leads toward the smart industries/buildings. STLF (Short Term Load Forecasting) is an essential component that an industrial plant requires to manage the power, regarding the load fluctuations during production, and compulsory requirement of cost mitigation. This thesis, in order to... 

Fossil fuel are energy resources in decline. In recent years, fuel cell have become as a source of energy to replace conventional systems .Among the various types of fuel cells, PEMFCs (proton exchange membrane fuel cells) possess a series of highly advantageous features such as a low-operating temperature, sustained operation at high-current density, low weight, compactness, potential for low cost and volume, long stack life, fast start-ups and suitability for discontinuous operation. Water management is one of the most critical and challenging problems. There is a delicate balance between the membrane hydration and avoiding cathode from flooding. Cathode flooding occurs when the water... 

A two-dimensional, two-phase, nonisothermal model was developed in this work to investigate the water transport characteristic and water distribution in a direct methanol fuel cell (DMFC). Emphasis is placed on exploring the water distribution in different layers of DMF. The water and methanol crossover through the membrane were considered with the effect of diffusion, electro-osmotic drag, and convection. Governing equations including the prton and electron transport, continuity, momentum, species transport for methanol, water, and gases species, and the auxiliary equations are coupled to determine the output parameters. These parameters are the concentration distribution of the species,... 

Network coding, as a promising method for data exchange in wireless communication network, is investigated by many researchers. However, the random nature of packet generation and transmission as well as the collision among transmitted packets have not been fully addressed in network codingrelated literature. In this dissertation, we analyze the network coding-based wireless network from this point of view. In order to achieve this goal, we apply mathematical tools such as probability theory and queuing theory. In the first part of this dissertation, we address the interaction between MAC and network coding. In this respect, we consider a multihop tandem wireless network, where each node is... 

In the proton exchange membrane fuel cells (PEM, the produced water would be divided into two phases of vapor and liquid. distribution of both liquid and vapor phases in different cell layers affects the performance, the efficiency and the life of a fuel cell significantly. Moreover, Nano pores of the cathode catalyst layer are involved with some phenomena such as electrochemical reaction kinetics, heat and mass transfer and interface phase change. One of the most important problems in the performance of fuel cells is distribution of liquid water in the porous areas. Water flooding in fuel cells causes to delay in oxygen transport to active sites in the catalyst layer because the pores of... 

Fuel Cell with Polymer membrane uses a reaction with Hydrogen and Oxygen as reactants to produce electricity. As the product of this reaction is water, this fuel cell produce clean energy. But if the produced water accumulates it can cause problems for fuel cell which can lead to complete failed of fuel cell. On the other hand water shortage in PEM fuel cell also can cause problems. So we need to have continues water management inside of PEM fuel cell. For this sake having knowledge about water inside of PEM fuel cell and specially the Gas Diffusion Layer which is the layer with responsibly to help the fuel cell to manage the water, is necessary. One of the ways for gaining that knowledge... 

The human need for reliable and accessible energy sources for household, industrial, transportation, etc. caused the discovery of the first oil well to move towards exploitation and use of this large, cheap and available energy source, accelerated. With the start of this movement, oil and its products in the last two centuries have quickly established themselves as a major part of the energy basket of most countries in the world. The entry of crude oil and its products into the energy industry has faced new issues and challenges for decision makers in this field. One of the most important challenges has been the planning and management of the process of distribution and transfer of petroleum... 

In this thesis, we argue that in many basic algorithms for machine learning, including support vector machine (SVM) for classification, principal component analysis (PCA) for dimensionality reduction, and regression for dependency estimation, we need the inner products of the data samples, rather than the data samples themselves. Motivated by the above observation, we introduce the problem of private inner product retrieval for distributed machine learning, where we have a system including a database of some files, duplicated across some non-colluding servers. A user intends to retrieve a subset of specific size of the inner products of the data files with minimum communication load, without... 

Using energy storage systems has been remarkably improved the energy systems efficiency and reliability indicators of the system and also reduced the operating costs of these systems. Thus using them in an energy system would count as an advantage. Lately, the procedure of implementation of these systems has been studied widely and various motives behind implementing them have been reviewed. For example, the effect of cost optimization in electrical vehicles on reliability indicators from the load management perspective can be addressed. Therefore this thesis has studied the effect of electrical and thermal storage systems on the reliability indicators of an energy hub and the effect of... 

This thesis presents a stochastic framework to properly involve the uncertainties associated with demand in distribution system restoration (DSR) problem. The restoration process returns the system back to normal operation after any combination of system components have been lost due to an outage. During restoration, the system operator executes a set of actions that progressively mitigate the outage. These actions aim at minimizing the impact of the outage on the final user without compromising the security and operability of the system. In this framework, dynamic programming (DP) is used to solve DSR problem for a distribution system that accommodates various technologies of DG units and...