Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2007. / Includes bibliographical references (p. 35-36).

Zugl.: Potsdam, Universiẗat, Diss., 2008.

Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Mark Sussman, Florida State University, College of Arts and Sciences, Dept. of Mathematics. Title and description from dissertation home page (viewed Oct. 12, 2005). Document formatted into pages; contains xi, 104 pages. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 95-105). Also available in print.

Universiẗat, Diss., 2009--Bayreuth.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 163-172). Also available in electronic version.

Submitted by RICARDO CESAR CAMARA FERRARI null (rccferrari@hotmail.com) on 2018-04-05T15:50:10Z No. of bitstreams: 1 TESEV59.pdf: 2999220 bytes, checksum: d4796fb104f36a34069600090d6741e9 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-04-05T18:37:17Z (GMT) No. of bitstreams: 1 ferrari_rcc_dr_ilha.pdf: 2999220 bytes, checksum: d4796fb104f36a34069600090d6741e9 (MD5) / Made available in DSpace on 2018-04-05T18:37:17Z (GMT). No. of bitstreams: 1 ferrari_rcc_dr_ilha.pdf: 2999220 bytes, checksum: d4796fb104f36a34069600090d6741e9 (MD5) Previous issue date: 2018-03-01 / O trabalho propõe uma aplicação com o uso de desvio padrão para definir limites máximos e mínimos de pacotes e bytes para detecção de anomalias nos fluxos de comunicação entre mestre e escravos com o uso do protocolo DNP3 (Distributed Network Protocol v3.0) em uma Smart Grid, além de detecção e bloqueio de ataques originados de máquinas intrusas ou conhecidas. Atualmente, diversas pesquisas vêm sendo desenvolvidas sobre uso de sistemas Smart Grid, no entanto, sua implantação possui alguns fatores de risco. Esses fatores estão associados às redes de transmissão de dados, às tecnologias de aquisição e controle das informações, e às vulnerabilidades intrínsecas da união dessas tecnologias. A principal motivação dessa proposta origina-se da necessidade de se garantir segurança dos sistemas Smart Grid e o potencial apresentado pelas Redes Definidas por Software (Software Defined Networking – SDN) em analisar os fluxos de dados em um switch. Assim, a investigação dessas vulnerabilidades, bem como, a identificação de situações de ataques são relevantes a fim de propor soluções de defesa. Para isto, a tecnologia de SDN apresentou-se como uma solução viável e otimizada para a proteção de sistemas Smart Grid, permitindo que seja realizado um monitoramento dos fluxos entre mestre e escravos, e a coleta de informações para análise, abrindo oportunidades para aplicações de segurança em Smart Grid. Dessa forma, foram realizados três experimentos, o primeiro com o objetivo de mostrar a vulnerabilidade de uma Smart Grid, o segundo com o intuito de analisar uma aplicação SDN em uma Smart Grid e o terceiro com dois ataques DDoS (Distributed Denial of Service) em uma Smart Grid. O primeiro ataque a partir de máquinas intrusas e o segundo ataque, de escravas, permitindo analisar e monitorar o fluxo de dados e o bloqueio das portas em um Open vSwitch (OVS). Nesse contexto, um componente de um controlador SDN foi modificado para adicionar segurança e monitoramento da rede, tendo um comportamento satisfatório, identificando anomalias e conseguindo realizar bloqueios de portas das máquinas atacantes. / The work proposes an application with the use of standard deviation to define limits of maximum and minimum of packets and bytes for detection of anomalies in the communication flows between master and slave using the Distributed Network Protocol v3.0 (DNP3), besides the detection and blocking of attacks originated from intrusive or known machines. Currently several researches have been developed on the use of Smart Grid systems, however, its implementation has some risk factors. These factors are associated with data transmission networks, information acquisition and control technologies and intrinsic vulnerabilities of the union of these technologies. The main motivation of this proposal comes from the need to guarantee security of Smart Grid systems and the potential presented by Software Defined Networking (SDN). Thus, the investigation of these vulnerabilities, as well as, identification of situations of attacks are relevant in order to propose defense solutions. For this, the SDN technology has presented a viable and optimized solution for the protection of Smart Grid systems, allowing the monitoring of masterslave flows and the collection of information for analysis, opening opportunities for security applications in Smart Grid. In this way, three experiments were carried out, the first to show the vulnerability of an insecure Smart Grid, the second to analyze a SDN application in a Smart Grid and the third with two Distributed Denial of Service (DDoS) attack on a Smart Grid, the first from intrusive machines and the second from slaves, allowing to analyze and monitor the data flow and the lock of the doors in an Open vSwitch (OVS). In this context, a component of an SDN controller has been modified to add security and monitoring of the network, having a satisfactory behavior, identifying anomalies and being able to perform port blocking of the attacking machines.

Orientador: Ailton Akira Shinoda / Resumo: O trabalho propõe uma aplicação com o uso de desvio padrão para definir limites máximos e mínimos de pacotes e bytes para detecção de anomalias nos fluxos de comunicação entre mestre e escravos com o uso do protocolo DNP3 (Distributed Network Protocol v3.0) em uma Smart Grid, além de detecção e bloqueio de ataques originados de máquinas intrusas ou conhecidas. Atualmente, diversas pesquisas vêm sendo desenvolvidas sobre uso de sistemas Smart Grid, no entanto, sua implantação possui alguns fatores de risco. Esses fatores estão associados às redes de transmissão de dados, às tecnologias de aquisição e controle das informações, e às vulnerabilidades intrínsecas da união dessas tecnologias. A principal motivação dessa proposta origina-se da necessidade de se garantir segurança dos sistemas Smart Grid e o potencial apresentado pelas Redes Definidas por Software (Software Defined Networking – SDN) em analisar os fluxos de dados em um switch. Assim, a investigação dessas vulnerabilidades, bem como, a identificação de situações de ataques são relevantes a fim de propor soluções de defesa. Para isto, a tecnologia de SDN apresentou-se como uma solução viável e otimizada para a proteção de sistemas Smart Grid, permitindo que seja realizado um monitoramento dos fluxos entre mestre e escravos, e a coleta de informações para análise, abrindo oportunidades para aplicações de segurança em Smart Grid. Dessa forma, foram realizados três experimentos, o primeiro com o objetivo de mostrar a vuln... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The work proposes an application with the use of standard deviation to define limits of maximum and minimum of packets and bytes for detection of anomalies in the communication flows between master and slave using the Distributed Network Protocol v3.0 (DNP3), besides the detection and blocking of attacks originated from intrusive or known machines. Currently several researches have been developed on the use of Smart Grid systems, however, its implementation has some risk factors. These factors are associated with data transmission networks, information acquisition and control technologies and intrinsic vulnerabilities of the union of these technologies. The main motivation of this proposal comes from the need to guarantee security of Smart Grid systems and the potential presented by Software Defined Networking (SDN). Thus, the investigation of these vulnerabilities, as well as, identification of situations of attacks are relevant in order to propose defense solutions. For this, the SDN technology has presented a viable and optimized solution for the protection of Smart Grid systems, allowing the monitoring of masterslave flows and the collection of information for analysis, opening opportunities for security applications in Smart Grid. In this way, three experiments were carried out, the first to show the vulnerability of an insecure Smart Grid, the second to analyze a SDN application in a Smart Grid and the third with two Distributed Denial of Service (DDoS) attack on a Smar... (Complete abstract click electronic access below) / Doutor

This thesis contributes to improve the photovoltaic Distributed Generation (DG) systems by proposing three novel methods to the system. On DC conversion side, a new integrated magnetic structure for interleaved converter and a new method to calculate the eddy current and hysteresis losses in the magnetic core were proposed. On inversion side, A new synchronisation method for grid tie inverters was suggested. The technique is using the Recursive Discrete Fourier Transform (RDFT) to find fundamental in grid waveform. On the DC converter side, the benefits of the new structure is to produce magnetic flux that alternate in the core across both directions of the BH curve. The advantages of alternating magnetic flux are, to increase the Root Mean Square (RMS) value of produced current with respect to core volume that lead to reduce the core size and reducing losses by using high permeability material. Furthermore, the proposed structure led to reduce the number of magnetic components which helped to improve the efficiency. The converter was tested and evaluated were the results show that the topology is able to produce high gain and it shows that the new interleaved structure is efficient. A new method to calculate the eddy current loss was proposed, where the flux waveform in the core was analysed to its original frequency component. Each of the components were utilized individually to find the loss. The effect of changing the duty cycle of the converter was taken into consideration on the total eddy current loss, as it will effect on the total harmonics content in the flux waveform. On the inverter side, due to recent developments combined with the increasing power demand by single phase non-linear loads where voltage spikes, harmonics and DC component were impacted the electric grid quality. These effects can likewise make the synchronisation process a challenge, where filters or Digital Signal processing (DSP) analysers are required to acquire the fundamental component as a consequence to the waveform deformation. A new linear approximation with RDFT is presented in this thesis for grid tie inverters. The new method provides a computation reduction as well as high accuracy in tracking the fundamental frequency in a distorted grid during synchronisation. The method accuracy was proved mathematically and simulated with different input signals. Error in magnitude and frequency measurement were measured, presented and compared with other research in order to verify the proposed method.

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2007. / Submitted by Luis Felipe Souza (luis_felas@globo.com) on 2009-01-05T14:12:55Z No. of bitstreams: 1 Dissertacao_2007_GlauberScorsatto.pdf: 2122593 bytes, checksum: 53c097affeb6a78e961a465da8c004f1 (MD5) / Approved for entry into archive by Georgia Fernandes(georgia@bce.unb.br) on 2009-03-02T19:52:14Z (GMT) No. of bitstreams: 1 Dissertacao_2007_GlauberScorsatto.pdf: 2122593 bytes, checksum: 53c097affeb6a78e961a465da8c004f1 (MD5) / Made available in DSpace on 2009-03-02T19:52:14Z (GMT). No. of bitstreams: 1 Dissertacao_2007_GlauberScorsatto.pdf: 2122593 bytes, checksum: 53c097affeb6a78e961a465da8c004f1 (MD5) / Um sistema distribuído consiste em um conjunto de elementos computacionais que se comunicam através de uma rede de interconexão e que utilizam um software que permite que trabalhem de maneira cooperativa e coordenada. Visando o compartilhamento de recursos em larga escala, foi proposta a Computação em Grid, um tipo de sistema distribuído cujo objetivo é o compartilhamento de recursos geograficamente distribuídos, autônomos e pertencentes a diferentes domínios administrativos. Algumas aplicações executadas em grid podem necessitar de garantias de disponibilidade de recursos. Para que tais aplicações sejam satisfeitas, faz-se necessário o fornecimento de garantias de Qualidade de Serviço (QoS). QoS consiste em um conjunto de características quantitativas e qualitativas de um sistema necessárias para que seja alcançado o nível de serviço esperado pelas aplicações. Um meio de se fazer a negociação dos níveis de QoS fornecidos às aplicações é a utilização de acordos de serviço, pelos quais a parte fornecedora se compromete a prover o nível de serviço desejado. A presente dissertação propõe o GrAMoS (Grid Agreement Monitoring Service), um serviço capaz de monitorar acordos firmados em grid, assim como de detectar possíveis violações desses acordos e de tomar ações em caso de detecção de violações. A monitoração é feita em instantes randômicos dentro de intervalos fixos e as ações tomadas na situação de quebra de acordo são flexíveis e podem ser fornecidas pelo usuário. A análise do protótipo do GrAMoS, implementado no Globus Toolkit 4 (GT4), mostra que o overhead causado pelo monitoramento é baixo (abaixo de 2,8%), causando um impacto mínimo na aplicação de grid. _______________________________________________________________________________________________________________ ABSTRACT / A distributed system consists in a set of computational elements, which communicate through an interconnected network, making use of software that allows the elements to work in a cooperative and coordinate way. Aiming a large scale resource sharing, Grid Computing has emerged, a kind of distributed system which has as objective the sharing of autonomous, geographically distributed resources, belonging to different administrative domains. Some applications executed in a grid system may demand resource availability in some specific levels. For these applications to be satisfied, it is necessary to supply guarantees of Quality of Service (QoS). QoS consists of several quantitative and qualitative system characteristics which are necessary for the level of service demanded by applications to be achieved. A means of negotiating the QoS levels supplied for the applications is to use service agreements, by which the resource supplier compromises to supply the demanded level of service. The present dissertation proposes GrAMoS (Grid Agreement Monitoring Service), a service capable of monitoring agreements firmed in a grid, which can detect agreement violations and take actions. In our service, monitoring is done at random moments inside fixed intervals and the actions taken in the case of agreement violations are flexible and can be provided by the user. The evaluation of the GrAMoS prototype, which was implemented on top of the Globus Toolkit 4 (GT4), shows that the monitoring overhead is low (below 2.8%), causing a very small impact on the grid applications.