The world is facing many problems, including limited natural resources as well as environmental and energy problems. Climate change is a fact and has a negative impact on several areas. The development of society has created the need for secure and reliable energy systems. Therefore, energy production must keep up with recent developments while limiting negative environmental impact. Although the sharp increase of renewable energy sources connecting to electrical networks creates stress on energy systems. Maintaining the standard of living and achieving sustainable energy production requires a significant increase in the efficiency of energy use. In addition, the fact that there are presently an abundance of effective ways to store electricity means, and requires, that the production, as well as consumption, of power are kept in balance at all times. One of the basic operating forces regarding the Smart Grid is to balance energy consumption in the best way possible. The intelligent networks method is also advantageous for the environment as well as the consumers and producers of electricity. Although the broad sense of the Smart Grid includes the whole power system, ranging from power generation, transmission and distribution infrastructure to all categories of consumers (domestic, commercial and industrial). Smart Grids are also techniques that enable improved business continuity, increased connectivity and also helps to improve the efficiency of the corporate network, and indirectly reduce costs for consumers. Further measures in this area include power supply and system maintenance as well as information and communication technology. This study will provide knowledge and understanding in addition to contributing ideas on how to improve the wind power plants and the electricity grid through the use of Smart Grids. The analysis is also a way to convey an overall impression of how the Smart Grid works as well as summarizing the general requirements in order to achieve the best possible performance.

Stuttgart, Univ., Diss., 2007.

The concept of the smart grid has been proposed to modernize the power grid with efficient and comprehensive monitoring systems as well as autonomous and self-healing technologies. Demand response (DR) and demand side management (DSM) are two aspects of the smart grid. The first is used to control the demand and supply, and the peak-to-average ratio (PAR) of a distribution network, and the second is used to manage a site's energy consumption efficiently. This thesis focuses on reducing the need for importing extra electricity from resources outside the local distribution network using DR, DSM. First, a demand management model is described to optimize customer energy usage and consider their comfort within a sequential optimization model. A multi-layer and multi-objective optimization system is proposed at the energy consumption level to consider customer comfort and experience. The cluster-based sequential management approach is presented to improve customer comfort via appliance scheduling. To quantify thermal comfort, a thermodynamic solution is used for the heating ventilation, and air conditioning (HVAC) system to schedule thermal load and eliminate customer inconvenience on room temperature. Customer inconvenience refers to a condition that the use of an appliance does not meet the preferences of the customer. Moreover, the satisfaction of electric vehicle charging, constrained by minimum cost, and the preferred usage time for the non-interruptible deferrable loads are considered in this model. Due to the uncertain demand profile of users, stochastic solutions for demand response problems enable utility companies to address the uncertainties in the customers' energy consumption. A stochastic DR approach is presented between an aggregator and residential customers during peak load periods, and the optimal outputs of customers and aggregator are determined. This probabilistic demand response management model uses a mixed-strategy Stackelberg game to maximize the profit of total energy reduction for the aggregator and to maximize the reward of demand reduction for customers. The proposed solution reduces the demand, PAR, and the overall energy costs for both customers and the grid while maintaining customer comfort. To perform a secure and robust energy trading model with high scalable decentralized supervision, a mixed-strategy stochastic game model is integrated with energy blockchain to address uncertainties in DR contributions. This model utilizes the processing hardware of customers for block mining, stores customer DR agreements as distributed ledgers, and offers a smart contract and consensus algorithm for energy transaction validation. A novel consensus algorithm compatible with a DR problem is presented to incentivize customers to contribute to DR events and collaborate in block mining to gain monetary profits. The results demonstrate the security and robustness of the consensus algorithm for detecting malicious activities. In summary, this thesis proposes schemes that control grid demand and minimize energy usage while preserving user comfort, security, and economic fairness.

Computational Grids are large infrastructures composed of several components such as clusters, or massively parallel machines, generally spread across a country or the world, linked together through some network such as Internet, and allowing a transparent access to any resource. Grids have become unavoidable for a large part of the scientific community requiring computational power such as high-energy physics, bioinformatics or earth observation. Large projects are emerging, often at an international level, but even if Grids are on the way of being efficient and user-friendly systems, computer scientists and engineers still have a huge amount of work to do in order to improve their efficiency. Amongst a large number of problems to solve or to improve upon, the problem of scheduling the work and balancing the load is of first importance. <p> This work concentrates on the way the work is dispatched on such systems, and mainly on how the first level of scheduling – generally name brokering, or meta-sheduling – is performed. We deeply analyze the behavior of popular strategies, compare their efficiency, and propose a new very efficient brokering policy providing notable performances, attested by the large number of simulations we performed and provided in the document. <p> The work is mainly split in two parts. After introducing the mathematical framework on which the following of the manuscript is based, we study systems where the grid brokering is done without any feed-back information, i.e. without knowing the current state of the clusters when the resource broker – the grid component receiving jobs from clients and performing the brokering – makes its decision. We show here how a computational grid behaves if the brokering is done is such a way that each cluster receives a quantity of work proportional to its computational capacity. <p> The second part of this work is rather independent from the first one, and consists in the presentation of a brokering strategy, based on Whittle's indices, trying to minimize as much as possible the average sojourn time of jobs. We show how efficient the proposed strategy is for computational grids, compared to the ones popular in production systems. We also show its robustness to several parameter changes, and provide several very efficient algorithms allowing to make the required computations for this index policy. We finally extend our model in several directions.

Este texto apresenta nosso projeto de implementação de um arcabouço de suporte a agentes móveis dentro de um ambiente de grade denominado InteGrade. Nosso arcabouço - MobiGrid - foi criado de forma a permitir que aplicações seqüenciais longas possam ser executadas em uma rede de estações de trabalho pessoais. Os agentes móveis são utilizados para encapsular essas aplicações com longo tempo de processamento. O encapsulamento de uma aplicação com longo tempo de processamento dentro de um agente móvel é o que denominamos como tarefa. Sendo assim, as tarefas podem migrar sempre que a máquina é requisitada por seu usuário local, já que são providas com capacidade de migração automática. Nosso arcabouço também fornece ao usuário um gerente que rastreia as tarefas por ele submetidas. Baseados no ambiente de execução de tarefas descrito, criamos um modelo matemático para efetuarmos simulações de como se comportariam muitas tarefas submetidas a uma grade com grande quantidade de estações de trabalho. Neste trabalho apresentamos também esse modelo, bem como os resultados das simulações nele baseadas. / This text presents a project which focuses on the implementation of a framework for mobile agents support within a grid environment project, namely InteGrade. Our framework - MobiGrid - was created in such a way that time consuming sequential applications can be executed on a network of personal workstations. The encapsulation of a long processing application by a mobile agent is what we call task. Hence, the tasks can migrate whenever the local machine is requested by its local user, since they are provided with automatic migration capabilities. Our framework also provides the user with a manager that keeps track of the submitted agents. Based on the execution environment described above, we have created a mathematical model which allows us to simulate how a great quantity of tasks submitted to a grid with many workstations would behave. In this text, we also present our model, as well as the results of our simulations.

Este texto apresenta nosso projeto de implementação de um arcabouço de suporte a agentes móveis dentro de um ambiente de grade denominado InteGrade. Nosso arcabouço - MobiGrid - foi criado de forma a permitir que aplicações seqüenciais longas possam ser executadas em uma rede de estações de trabalho pessoais. Os agentes móveis são utilizados para encapsular essas aplicações com longo tempo de processamento. O encapsulamento de uma aplicação com longo tempo de processamento dentro de um agente móvel é o que denominamos como tarefa. Sendo assim, as tarefas podem migrar sempre que a máquina é requisitada por seu usuário local, já que são providas com capacidade de migração automática. Nosso arcabouço também fornece ao usuário um gerente que rastreia as tarefas por ele submetidas. Baseados no ambiente de execução de tarefas descrito, criamos um modelo matemático para efetuarmos simulações de como se comportariam muitas tarefas submetidas a uma grade com grande quantidade de estações de trabalho. Neste trabalho apresentamos também esse modelo, bem como os resultados das simulações nele baseadas. / This text presents a project which focuses on the implementation of a framework for mobile agents support within a grid environment project, namely InteGrade. Our framework - MobiGrid - was created in such a way that time consuming sequential applications can be executed on a network of personal workstations. The encapsulation of a long processing application by a mobile agent is what we call task. Hence, the tasks can migrate whenever the local machine is requested by its local user, since they are provided with automatic migration capabilities. Our framework also provides the user with a manager that keeps track of the submitted agents. Based on the execution environment described above, we have created a mathematical model which allows us to simulate how a great quantity of tasks submitted to a grid with many workstations would behave. In this text, we also present our model, as well as the results of our simulations.

This thesis concerns the viability of the 'Yin-Yang grid' for future generations of atmospheric models. The 'Yin-Yang grid’, is an overset grid in which two segments of the classical latitude-longitude grid, with the poles excised, are rotated relative to each other and fit together rather like the surface of a tennis ball. We investigate whether wave propagation can be accurately modelled across the overlap regions and whether transport of air mass properties, such as entropy or water content, can be modelled accurately and conservatively across the overlap regions, without significant 'grid imprinting' on the solution. The wave propagation results demonstrate that the overlapping regions support computational/spurious wave modes and methods for controlling these wave modes are discussed. Transport schemes are investigated in one dimension using the Chesshire and Henshaw conservative interpolation scheme [Chesshire and Henshaw 1984] and the new 'Zerroukat mass fixer' scheme. The Zerroukat mass fixer scheme is extended to the (two-dimensional) Yin-Yang grid. The results demonstrate that the Zerroukat mass fixer scheme is successful in conserving mass. However, the Zerroukat scheme has an effect on flux limiter schemes, overshoots can occur. The Zerroukat scheme also reduces convergence rates by 2 orders of accuracy. Therefore if 2nd order convergence is required a 4th order scheme would need to be used.

No description available.

Grid computing provides a powerful, virtual parallel system known as a computational Grid on which users can run parallel applications to solve problems quickly. However, users must be careful to allocate tasks to nodes properly because improper allocation of only one task could result in lengthy executions of applications, or even worse, applications could crash. This allocation problem is called the mapping problem, and an entity that tackles this problem is called a mapper. In this thesis, we aim to develop an efficient, practical, portable mapper. To study the mapping problem, researchers often make unrealistic assumptions such as that nodes of Grids are always reliable, that execution times of tasks assigned to nodes are known a priori, or that detailed information of parallel applications is always known. As a result, the practicality and portability of mappers developed in such conditions are uncertain. Our review of related work suggested that a more efficient tool is required to study this problem; therefore, we developed GMap, a simulator researchers/developers can use to develop practical, portable mappers. The fact that nodes are not always reliable leads to the development of an algorithm for predicting the reliability of nodes and a predictor for identifying reliable nodes of Grids. Experimental results showed that the predictor reduced the chance of failures in executions of applications by half. The facts that execution times of tasks assigned to nodes are not known a priori and that detailed information of parallel applications is not alw ays known, lead to the evaluation of five nearest-neighbour (nn) execution time estimators: k-nn smoothing, k-nn, adaptive k-nn, one-nn, and adaptive one-nn. Experimental results showed that adaptive k-nn was the most efficient one. We also implemented the predictor and the estimator in GMap. Using GMap, we could reliably compare the efficiency of six mapping algorithms: Min-min, Max-min, Genetic Algorithms, Simulated Annealing, Tabu Search, and Quick-quality Map, with none of the preceding unrealistic assumptions. Experimental results showed that Quick-quality Map was the most efficient one. As a result of these findings, we achieved our goal in developing an efficient, practical, portable mapper.

<p>The fact is, no organization has ever become great without exceptional leadership - without leaders who can connect the efforts of their teams to the critical objectives of the organization, who can tap the full potential of each individual on their teams, who can align systems and clarify purposes, and who can inspire trust. The purpose of the study is to investigate and compare what management styles business students from Halmstad University, Sweden, will implement. Moreover, this study shows future leaders work preferences and concerns. As a tool for the findings the managerial grid (founded in 1964 by Blake and Mounton) was incorporated with situational theory (Hersey and Blanchard, 1977). The investigation was conducted applying a theoretical framework to empirical data. By analysing leadership styles and students work preferences, it illustrates the kind of leader a business student will potentially become and which direction he/she may take. Overall, the average of 130 business students from Halmstad University shows that they are going to be a Team Leader, because for them the people’s needs as well as the results of their work are important.</p>