Sharif Digital Repository

In recent years, due to the increase in distributed generation, the use of renewable energy sources and the emergence of restructuring and energy markets, traditional distribution networks transform to complex and active distribution networks. These issues, along with requirements such as increasing power quality and reliability, have increased the need to provide active distribution management systems and the use of effective network monitoring, control and protection systems. Due to the complexity and expanse of distribution networks, as well as the development of the use of metering elements and remotely controllable elements, one of the important issues in these systems is the... 

This paper proposes a novel real-time pricing tariff design aiming at reducing the operation cost of distribution system. A customer base-line load (CBL) is established for each participant. It let the customer to have less exposure with RTP volatile prices.The tariff charges the consumption above the CBL an hourly varying price. It credits the consumption below the CBL another hourly varying price.The proposed tariff provides the participant with more incentive and discount prices to encourage it to consume more efficient. The optimal prices are determined and announced a day in advance but can change in the next day with a short notice.The response of customers to the tariff prices is... 

One of the most important characteristics of real-time systems is executing tasks before their specified deadlines. The tasks’ execution may require several resources like processor, I/O ports, and data structures. Some of these resources may be shared between several tasks and their availability is important in executing tasks before the deadlines. Allocating shared resources which are used in mutually exclusive manner often encounteres some problems such as priority inversion and deadlock. Resource access protocols are used to minimize or eliminate these problems. The effect of using these protocols issupporting tasks’ execution before their deadlines. To meet deadlines is of decisive... 

Nowadays, power systems are facing significant changes in traditional network operation and planning approaches with the introduction of distributed generation energy sources and increasing concerns about environmental issues. On the other hand, the Distribution Management System (DMS) in the current situation with low levels of observability and automation, controls and monitors the distribution network, which will not meet the challenges of the Active Distribution Network (ADN). For this purpose, in the first part of this dissertation, considering that the supply of network loads is important from the operator and distribution network management point of view and the voltage range and... 

The major goal of the power industry is to serve the demand of electricity consumers as reliable as possible but at an affordable cost. Towards the goal, however, the industry faces substantial barriers such as aging infrastructures, growing demand, and limited budgets for reinforcements. A great portion of infrastructures which were built decades ago need to be retired. The growing demand needs system reinforcement and expansion. These, in turn, require considerable amounts of investment which is in contradiction with highly limited budget of the power industry. This critical situation forces the industry to utilize the existing system more efficiently and wisely. To this end, the concept... 

In recent years, the pace of increment in electrical energy consumption is getting faster. Establishing new power-plants to keep a balance between generation and consumption not only has a high investment cost but also is a time consuming procedure. Thus, several studies have focused on the demand side management. Residential consumers possess remarkable portion of total electricity consumption. Accordingly, at first, the appropriate residential demand response program is selected based on presented experimental criteria. In the next step, since the network reliability is an important issue to the operators, the impact of implementation of the demand response program is studied on the... 

In various industries, particularly in the process industries, computational fluid dynamics (CFD) stands as the predominant method for simulating distributed systems. In these methods, discretization of system geometry and partial differential equations is necessary, resulting in a system of algebraic or ordinary differential equations, or a combination thereof. The significant computational demands arising from the extensive number of equations derived from dynamic system simulations highlight the necessity for substantial processing and computing power. The objective of this project is to reduce the computational load associated with solving these equations. It focuses on utilizing machine... 

In communications systems, coding is used to combat channel errors. The redundancy introduced by coding enables the detection and/or correction of errors occurring in the channel. In addition to communications systems, coding is also beneficial in various other systems such as distributed storage systems and blockchain systems to cope with node failures, data erasures, and adversarial behaviors attempting to modify information. In existing applications of coding, it is generally assumed that the encoding operation is performed correctly and without errors, and errors are applied to the encoded data. In recent years, applications have emerged where the assumption of error-free encoding is not... 

Emergence of crypto-currency and blockchain technology revolutionize supply chain processes. In addition, customer needs for more information on products or services from origin to destination, highlights the necessity of transparency, originality and traceability in supply chains. This research is aimed to develop a blockchain based system ascertaining supply chain transparency and originality. To this aim, a joint pricing and closed-loop supply chain network design problem is selected as a good platform to implement it. Due to increasing concerns on environmental issues and maximizing job opportunities, sustainability is also considered in the proposed problem. To ascertain transparency... 

In distributed systems, a huge amount of data is dispersed among different nodes; centralization of this data is infeasible due to communication and storage costs. In addition, Databases with high dimensional data objects are becoming more prevalent is many areas. When the dimensionality increases, the volume of the space increases so fast that the available data becomes sparse. This sparsity is problematic from many aspects. In order to obtain a statistically sound and reliable result, the amount of data needed to support the result often grows exponentially with the dimensionality. Also organizing and searching data often relies on detecting areas where objects form groups with similar... 

A workflow management system is a software system which manages and coordinates the operational tasks of an organization. Typically, the def­ inition of a workflow involves human and computer resources and tools on various geographic locations, and thus the concerns of distributed systems are one of the main challenges in this domain. Following this,allocating various resources to different tasks of a workflow and schedul­ ing them in a manner which satisfies some predefined constraints is one of the new and fundamental challenges in this field.The main goal of this research is to design an agent-oriented workflow system which utilizes a novel method for resource allocation and schedul­ ing... 

There is an increasing trend nowadays toward Distributed Generation (DGs). DG poses positive and negative side effects for both utility and customers. Reduction of system expansion costs, decreasing power loss and reliability enhancement are some benefits of DGs. Connecting DGs to the distribution system can lead to some troublesome issues. Anti-islanding protection is one of these issues. Islanding is the situation in which a distribution system becomes electrically isolated from the remainder of the power system, yet continues to be energized by DG connected to it. Traditionally, a distribution system doesn’t have any active power generating source in it and it doesn’t get power in case... 

The development of smart meters enables gathering and analysis of a large amount of data about electrical energy consumption in electric power distribution systems. This data and the obtained behavioral patterns of customers have a wide variety of applications. To name a few, classification of customers based on their consumption patterns, damaged smart meter identification, non-technical loss identification and measuring participation rate of customers in demand response programs are among the applications. So far, many studies have been done for consumption pattern identification. However, abnormality detection in electric energy consumption has captured growing attention due to the... 

Capacitor setting and reconfiguration are of main means of loss reduction and voltage profile improvement in distribution system operation. Cooperation between these two strategies can effectively minimize power losses in distribution system automation. Also, from the medium and long term viewpoint, capacitor placement and reconfiguration can be used for loss reduction and reliability enhancement. In this section, the sum of losses cost, capacitor investment cost and reliability cost should be minimized. Regarding the need to solve two non-linear combinatorial optimization problems simultaneously, metaheuristic algorithms are used in this thesis. Specifically, Elitist Genetic Algorithm,... 

Nowadays, improvement in operational condition of distribution networks considering daily growth in electrical energy usage with financial limits appears as a huge challenge for network operators. Under these kind of circumstances, operators need to have efficient and inexpensive plans more than ever. Considering high share of power losses in overall pro-duced power, utilities always tried to minimize losses in Iran and other points of world. In addition, numerous equipment in distribution networks compared with the transmission level, impose high costs to reliability plans. Therefore, reliability improvement plans have been paid low attention by distribution network operators. This lower... 

Developing distributed systems is always harder than centralized systems, because in distributed systems there are problems like how nodes must collaborate with each other, throughput, latency and so on, that is not concerned in centralized systems. For solving this problem, It's better to have an abstract view of system to show this concerns. one of the coordination languages to have that abstract view of system, is Reo language. Reo language is a coordination language that describe how components of systems, can coordinate with each other. This project is built to decrease the distance between designing and implementing. In this project an abstract view of system which is in Reo language,... 

Issues related to the environmental pollution, greenhouse gas emissions, as well as the limited supply of fossil fuels and their rising prices have led to the deployment of distributed energy technologies in power systems. With the increasing penetration of distributed energy sources in distribution systems, smart grids, and in particular, microgrids have emerged as a suitable and widely accepted solution for controlling and utilizing these resources. Microgrids can enhance energy efficiency in a sustainable power grid as well as the reliability of the distribution system, through supporting high penetration of renewable energy sources and providing island performance.In view of growing... 

The objective of the present research work has been the development of a model of optimal distribution electrical energy which may include distributed generators. Electrical distribution company has the option of receiving electric power from distributed generators owned by customers (Private Companies), DGs belonging to the electrical distribution company and purchase of power from market (high voltage network). The electrical distribution company would alternatively be able to sell surplus of its generation to the power market (high voltage network). The model of distribution system depicts the flow of electricity in each hour interval. The restrictions and bounds are the flows in each... 

In a distributed system, each solution for the problem of Byzantine Agreement requires that some of correct processes reach a common decision value from a set of proposed values while Byzantine processes may behave arbitrary. This problem is one of the most fundamental problems in the theory of distributed systems. While the problem has been widely studied in fully-connected fixed networks, few studies have been carried out in the context of self-organizing mobile networks such as Mobile Ad-Hoc Networks.
This research presents a randomized consensus protocol with three additional modules for the case of dynamic networks: Participant Detectors, Failure Detectors and Maintainer. We assume... 

Nowadays, development of renewable electricity generation technologies, the advent of small efficient generators and increasing number of grid-connected consumers, have caused increasing interest in energy production next to the consumers locations. Distributed generation (DG) is often defined as small-scale generators that produce several kilowatts to tens of megawatts of electricity. One primary reason for using DG is its potential to reduce power losses in transmission and distribution networks. Several loss reduction methods such as capacitor placement, network reconfiguration and load management are used in distribution systems. Employing DG results in the highest loss reduction and...