L'Internet et ses utilisateurs font quotidiennement l'objet d'attaques à l'aide de logiciels malveillants. Les vers, qui font partie de ces logiciels, se distinguent des autres moyens d'attaque par leur propagation automatique, qui les rend potentiellement dangereux. Pour faciliter leur propagation et la rendre plus rapide, les vers peuvent, entre autres, s'attaquer aux applications les plus prisées par les utilisateurs. La généralisation de l'utilisation des réseaux Pair-à-Pair par les internautes fait de ces réseaux une cible parfaite pour des vers appelés "vers Pair-à-Pair". Ces vers, et en particulier ceux d'entre eux qui sont passifs, sont caractérisés par leur furtivité. En effet, ils ne génèrent aucun trafic suspect, ce qui rend leur détection dans le réseau difficile. Le but de cette thèse est de proposer une solution efficace contre les vers Pair-à-Pair passifs, afin de sécuriser les réseaux Pair-à-Pair, qui commencent à être utilisés pour distribuer du contenu légal, comme la vidéo à la demande. Ainsi, nous proposons une architecture et des algorithmes pour détecter les vers Pair-à-Pair passifs dans le réseau. Nous évaluons nos algorithmes dans un simulateur que nous avons développé, ainsi qu'à l'aide d'une étude analytique. Nous nous intéressons ensuite à la mitigation des vers détectés dans le réseau. / The Internet and its users are daily the object of attacks of malware. Among them, we can find the worms, which distinguish themselves from the other attacks by their automatic way of propagation. This makes them potentially very dangerous. To make their propagation easier and faster, the worms can attack popular applications. The generalization of the use of Peer-to-Peer networks makes them a perfect target of worms called "Peer-to-Peer worms". These worms, and in particular the passive ones, are characterized by their stealthy. Indeed, they generate no suspect traffic, and are so difficult to detect in the network. The purpose of this thesis is to propose an effective solution against the passive Peer-to-Peer worms, to make Peer-to-Peer networks, which begin to be used to distribute some legal contents such as the VoD (Video on Demand) ones, more secure. We propose several algorithms and an architecture to detect the passive Peer-to-Peer worms in the network. We evaluate our algorithms in a simulator which we have developed, as well as with an analytical study. We then study the mitigation issue of the detected worms.

The City of Watsonville is vulnerable to a number of natural and man-made hazards. This project analyzed this risk and vulnerabilities to critical facilities within the city, and made recommendations of mitigation strategies and implementation methods to address this risk. Analysis and data collection was conducted in coordination with the City of Watsonville Fire Department and the resulting product will be given to the City for their use and potential adoption. The documents within this Local Hazard Mitigation Plan was developed to the standards and specifications developed by the State of California and Federal Emergency Management Agency for a Local Hazard Mitigation Plan in order for the opportunity for the City of Watsonville to be able to use the information contained here to develop a State and Federally-approved Local Hazard Mitigation Plan. The hazards analyzed within this document are as follows: earthquakes, wildfires, urban and industrial fires, flooding, hazardous materials, liquefaction, land subsidence, landslides, unreinforced masonry, airport hazards, civil disturbance/terrorism, dam failure, drought, expansive soils, natural gas pipeline failure, vehicle collisions, tornados, and tsunamis.

Numerous approaches have been proposed in order to resolve the problems of current harmonics in electrical distribution systems. The rapid development of power semiconductors along with the revolutionary advances on microprocessors consolidated the motor drives industry and with it a massive proliferation of non-linear loads. It was thought that these very same technological advances would trigger an explosive development of harmonic solutions based on power electronics. Moreover, the introduction of the instantaneous active and reactive power theory or the so-called p, q theory which simplifies and gives more robustness to the control strategies of active filters reinforced this idea. Three decades have passed since the first IGBT was introduced in early 1980s, and active harmonic solutions are not the first choice to solve harmonic pollution in electrical distribution systems, mainly due to the high cost and the perception of low reliability. Given this scenario, in this work two main approaches are explored. First, the combination of an asymmetric 18-pulse rectifier with a reduced KVA active harmonic filter to improve the performance under abnormal utility conditions. Second, an interleaved active harmonic filter using multiple inverters connected in parallel at the ac and dc size, which will allow for higher power ratings and power density increase. The performance issues of the asymmetric 18-pulse rectifier under unbalanced voltage and pre-existing harmonic components are analyzed, as well as the current distortion improvement, achieved when an active power filter is introduced. On the other hand, the high frequency harmonic cancellation when interleaved inverters are used, the circulation of zero-sequence current and the impact of interleaving on dc bus capacitor are analyzed. Finally, some methods to mitigate the low frequency circulating currents based on eliminating the zero-sequence component, and the introduction of common mode inductors to reduce the high frequency circulating current are studied. Without a doubt the search for new cost-effective topologies able to reach broader power levels and voltage ranges will continue emerging giving more alternatives to users. Moreover, extensive research on wide band gap devices such as Silicon Carbide (SiC) and Gallium Nitride (GaN), with which it is possible to reach higher voltage breakdown and at least an order-of-magnitude lower switching losses, makes the future more promising for active solutions.

Thesis (M.S.)--Pennsylvania State University, 2009. / Mode of access: World Wide Web. Thesis advisor: Robert P. Brooks.

Tourism mitigation is a contentious issue that requires a multifaceted approach to effectively achieve. The need to reduce personal traveling expenditure in order to mitigate the greenhouse gas emissions caused by tourism has not suitably been infiltrated within the public consciousness. Furthermore, those travellers who have been exposed to the reality that greenhouse gas emissions from tourism has often disregard that information and continue with their behaviour regardless.  This thesis aimed to investigate the reasons why those who travel the most in society, the hypermobile, choses to travel as much as they do and how this demand for travel could be curbed. It focused on three forms of tourism mitigation; government regulations, increases to the price of air travel and social marketing. The study was conducted with 10 individuals who self-identify as being highly mobile (more than 3 international return trips per year). The results showed that those who no single method of tourism mitigation would be effective in the goal of limiting highly mobile behavioural tendencies. A mixture of all three methods would be required in reaching the goal of lowering the levels of distance air travel consumption.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 72-75). Also available on the World Wide Web.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xii, 99 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 80-83).

No description available.

The design of buildings for extreme loads has traditionally been conducted on a life safety basis. As a result, buildings often need to be demolished after an extreme event since the cost of repairing the extensive damage is too great. For many buildings, especially critical infrastructure, continued operation after an explosive attack is essential. The use of energy-dissipating methods in a componentized system will enable the protection of a structure and occupants from a blast and permit the rapid repair and re-occupation of the building after an explosive attack. This study focuses on the characterization of a componentized system utilizing energy-dissipating component assemblies. From this characterization, a predictive theory, based on a single degree of freedom model, is developed and a general design method proposed. The predictive theory and design method are evaluated in field blast tests.

The design of buildings for extreme loads has traditionally been conducted on a life safety basis. As a result, buildings often need to be demolished after an extreme event since the cost of repairing the extensive damage is too great. For many buildings, especially critical infrastructure, continued operation after an explosive attack is essential. The use of energy-dissipating methods in a componentized system will enable the protection of a structure and occupants from a blast and permit the rapid repair and re-occupation of the building after an explosive attack. This study focuses on the characterization of a componentized system utilizing energy-dissipating component assemblies. From this characterization, a predictive theory, based on a single degree of freedom model, is developed and a general design method proposed. The predictive theory and design method are evaluated in field blast tests.