No description available.

München, Techn. Univ., Diss., 2004.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Understanding the processes related to the movement of water in soil profile is relevant to the management of soil and water resources. Hydraulic conductivity is an important soil property that affects this movement, but its determination in laboratory conditions requires that samples are contained in cylinders which can cause the presence of preferential flow through the soil wall interface. So, the goal of this work was to test the effect of increasing perimeter and height of the sample on saturated hydraulic conductivity in confined soil samples of different textures. Soil samples were collected and the following physical analyzes were performed: particle density, particle-size, water dispersed clay, soil porosity, and saturated hydraulic conductivity (Ko). Experimental data were analyzed in a randomized design for all variables, adopting a 4 x 5 factorial arrangement (four diameters x five heights of the cylinders), with six replications. The Shapiro- Wilk test was used to verify the normality of the data, F test for analysis of variance, and TukeyÂs test for comparison of means (p<0.05). Classical descriptive statistics and multivariate analysis techniques were also employed. It was conclude that: a) the results support the hypothesis that the increase of the perimeter causes an increase of the saturated hydraulic conductivity; b) for the same increase of preferential flow area, the effect on the saturated hydraulic conductivity was higher for clay soil; c) the hypothesis that increased water path causes a change in the Ko values was rejected; d) for both soil classes increased water path did not affect the values of the saturated hydraulicconductivity. / A compreensÃo dos processos relacionados ao movimento da Ãgua no perfil do solo à relevante para o manejo do solo e dos recursos hÃdricos. A condutividade hidrÃulica à um importante atributo do solo que interfere nesse movimento, sendo que sua determinaÃÃo na condiÃÃo de laboratÃrio requer que as amostras estejam confinadas em cilindros, o que pode causar a presenÃa de fluxo preferencial pela interface solo/parede do cilindro. Objetivou-se nesse trabalho testar o efeito do aumento do perÃmetro e da altura da amostra sobre a condutividade hidrÃulica do solo saturado em amostras confinadas de terra de diferentes texturas. Foram coletadas amostras de terra para realizaÃÃo das anÃlises fÃsicas, a saber: densidade de partÃculas, granulometria, argila dispersa em Ãgua, porosidade do solo e condutividade hidrÃulica do solo saturado (Ko). Os dados experimentais foram analisados em delineamento inteiramente casualizado para todas as variÃveis, adotandose o esquema fatorial 4 x 5 (quatro diÃmetros e cinco alturas dos cilindros), com seis repetiÃÃes. Foram aplicados os testes de Shapiro-Wilk para verificar a normalidade dos dados, o F para anÃlise de variÃncia e o de Tukey para a comparaÃÃo da mÃdias (todos a 5% de probabilidade). TambÃm foi empregada a estatÃstica descritiva clÃssica para algumas variÃveis e tÃcnicas multivariadas de anÃlises. Conclui-se que a) aceita-se a hipÃtese de que o aumento do perÃmetro da amostra provoca aumento nos valores de condutividade hidrÃulica do solo saturado; b) para o mesmo aumento de Ãrea de fluxo preferencial, o efeito sobre a condutividade hidrÃulica do solo saturado para o solo argiloso foi maior; c) a hipÃtese de que o aumento do percurso da Ãgua causa alteraÃÃo nos valores de Ko foi refutada; d) para ambas as classes de solos o aumento do percurso da Ãgua nÃo foi determinante nos valores obtidos para condutividade hidrÃulica do solo saturado.

No description available.

In this study we provide a new proof of C¹,α boundary regularity for finite perimeter sets with flat boundary which are local minimizers of a variational mean curvature formula. Our proof is provided for curvature term H∈LΩ. The proof is a generalization of Cafarelli and C#243;rdoba's method, and combines techniques from geometric measure theory and the theory of viscosity solutions which have been developed in the last 50 years. We rely on the delicate interplay between the global nature of sets which are variational minimizers of a given functional, and the pointwise local nature of comparison surfaces which satisfy certain PDE. As a heuristic, in our proof we can consider the curvature as an error term which is estimated and controlled at each point of the calculation.

A distributed fiber optic sensor with the ability of detecting and locating intruders on foot and vehicles over long perimeters (>10 km) was studied. The response of the sensor to people walking over or near it and to vehicles driving nearby was observed and analyzed. The sensor works on the principle of phase sensitive optical time domain re ectometry, making use of interferometric effects of Rayleigh backscattered light along a single mode fiber. Light pulses from a highly stable Er:doped fiber laser emitting single longitudinal mode light and exhibiting low frequency drift are passed through one end of the buried fiber. The backscattered light emerging from the same fiber end was monitored using a photodetector. The phase changes produced in the light pulse due to the pressure of the intruder walking directly above or near the sensor or from the seismic disturbances created by vehicles moving in the vicinity of the sensor are detected using the phase sensitive Optical Time Domain Re ectometer (OTDR). Field tests were conducted with the sensing element as a single mode fiber in a 3-mm diameter cable buried at depths ranging from 8 to 18 inches in clay soil. It was observed that the sensor could detect intruders walking transverse to the cable line at a distance of 40 ft from it. A car moving at a speed of 30 mph on a rough road could be consistently detected up to a distance of 480 ft from the sensor, while a car driven on a smooth road 200 ft from the sensor could be detected only when passing through rough patches on the road. Tests were also performed with an intruder walking near the sensor while a car was driven at a speed of 30 mph on a rough road. The effect on the signal due to the intruder on foot could be distinguished clearly only when the car was at least 200 ft away from the sensor. The results in this thesis represent the first quantitative study of the sensitivity of the sensor under varied test conditions. It is expected that these findings will be helpful in the practical implementation of the long perimeter intrusion sensor along high security domains like national borders, military bases and government buildings.

Syftet med denna studie är att studera elevers svårigheter i hanterandet av matematikuppgifter gällande omkrets och area samt att undersöka hur elevers kunskaper motsvarar kursplanens uppnående- och strävansmål. Kvalitativt inriktade intervjuer har använts som undersökningsmetod, då studiens huvudsakliga syfte har varit att på djupet undersöka och ge exempel på elevers förståelse. Elevsvaren har analyserats utifrån hur representationsformer, begreppsuttryck och innehåll används gällande omkrets, area och kursplanens mål. Eleverna visar svårigheter gällande omkrets- och areamätning och areakonservering, vilket utgör uppnåendemål inom målet att kunna undersöka matematiska problem och uttrycka sig muntligt med hjälp av grundläggande matematiska begrepp. Elevernas förståelse ökar när de får visa och förklara sin förståelse muntligt och med hjälp av bilder. / The aim of this study is to find pupils difficulties handling mathematical problems concerning perimeter and area and to examine in what way pupils knowledge match the curriculum striving and achieving goals. The main focus is qualitative interviews since the aim of the study is to examine and exemplify pupils understanding. The students’ answers to the mathematical tasks are focused and analyzed from the way pupils handle representations, expressions and contents about perimeter and area and from the curriculum goals. The result shows the pupils difficulties concerning measuring perimeter and area, area constancy, the curriculum achieving goals concerning examine mathematical problems and the ability to express oneself orally by using fundamental mathematical conceptions. Their understanding increases when they are allowed to show and explain their understanding orally and by means of illustrations.

Background. In the field of risk management, focusing on digital infrastructure, there is an uncertainty about which methods and algorithms are relevant and correct. Behind this uncertainty lies a need for testing and evaluation of different risk management analysis methods in order to determine how effective they are in relation to each other. Purpose. The purpose of this thesis is to manufacture a reproducible and universal method of comparison between risk management analysis methods. This is based on the need to compare two risk assessment analysis methods. One method relies solely on impact information and the other expands on that concept by also utilizing information about the network environment. Method. A network is modeled into a scenario. A risk assessment is conducted on the scenario by risk assessment experts which will be used as the correct solution. The tested risk management analysis methods are applied to the scenario and the results are compared with the expert risk assessment. The distance between the assessments are measured with Mean Square Error; A smaller distance between one assessment and the experts assessment indicates that it is more correct. Result. The result shows that it is possible to reproducibly compare risk management analysis methods by comparing the respective output with an established truth. The conducted comparison shows that a method that use network environment data is capable of producing a more correct assessment than one which simply uses impact data. Conclusion. A scenario based approach to compare risk management analysis methods for risk assessment has been proven effective.

This work was motivated by the famous Plateau\'s Problem which concerns the existence of a minimizing set of the area functional with prescribed boundary. In order to solve the Plateau\'s Problem, we make use of different theories: the theory of varifolds, currents and locally finite perimeter sets (Caccioppoli sets). Working on the Caccioppoli sets theory, it is straightforward to prove the existence of a minimizing set in some classical problems as the isoperimetric and Plateau\'s problems. If we switch the problem to find the regularity that we can extract of some minimizing set, we come across complicated ideas and tools. Although, the Plateau\'s Problem and other classical problems are well settled. Because of that, we have extensively studied the almost minimizing condition ((; r)-minimizing sets) considered by Maggi ([?]) which subsumes some classical problems. We focused on the regularity theory extracted from this almost minimizing condition. / This work was motivated by the famous Plateau\'s Problem which concerns the existence of a minimizing set of the area functional with prescribed boundary. In order to solve the Plateau\'s Problem, we make use of different theories: the theory of varifolds, currents and locally finite perimeter sets (Caccioppoli sets). Working on the Caccioppoli sets theory, it is straightforward to prove the existence of a minimizing set in some classical problems as the isoperimetric and Plateau\'s problems. If we switch the problem to find the regularity that we can extract of some minimizing set, we come across complicated ideas and tools. Although, the Plateau\'s Problem and other classical problems are well settled. Because of that, we have extensively studied the almost minimizing condition ((; r)-minimizing sets) considered by Maggi ([?]) which subsumes some classical problems. We focused on the regularity theory extracted from this almost minimizing condition.

Remote access is a way of providing access to networks from outside the premises of the network. Virtual Private Network (VPN) is one solution used to provide remote access. Software-Defined Perimeter (SDP) is another solution that is capable of providing access to resources from a remote location. These two technologies use different security models yet provide comparable remote access functionalities. This thesis project investigates the basic components, architecture, and security services of SDP and IPSec VPN. Additionally, a performance evaluation is conducted on SDPand VPN on their connection setup time and network throughput. Our result shows that both SDP and VPN provide secure access, however, SDP has additional features that make it a more secure solution. This thesis project is written in the hopes that it can help enterprises with or without a VPN solution already in place to consider SDP as an alternative solution and learn SDP in comparison with VPN.