This study presents a theoretical basis for and outlines the method of finding the Lie point symmetries of systems of partial differential equations. It seeks to determine which of five computer algebra packages is best at finding these symmetries. The chosen packages are LIEPDE and DIMSYM for REDUCE, LIE and BIGLIE for MUMATH, DESOLV for MAPLE, and MATHLIE for MATHEMATICA. This work concludes that while all of the computer packages are useful, DESOLV appears to be the most successful system at determining the complete set of Lie symmetries. Also, the study describes REDUCEVAR, a new package for MAPLE, that reduces the number of independent variables in systems of partial differential equations, using particular Lie point symmetries. It outlines the results of some testing carried out on this package. It concludes that REDUCEVAR is a very useful tool in performing the reduction of independent variables according to Lie's theory and is highly accurate in identifying cases where the symmetries are not suitable for finding S/G equations.

The expectation gap is the definition of the differences between what the interests expects from the auditor and what the auditor delivers. A number of studies have been done regarding the expectation gap and generally they point at the existence of an expectation gap. In our paper we want to discover and see how strategies are used in the process to reduce the expectation gap from three levels. The levels we treat are auditors, audit bureaus and the profession. We have chosen to examine the strategies used by the three levels to reduce the expectation gap to following interest groups, owners, management/board of directors, and creditors.The purpose with our paper is to create understanding about how auditors, audit bureaus and the profession use strategies in the process to reduce the expectation gap. With existing theories as ground we have construed and developed our own theory about which thinkable strategies the three levels can use. We have interviewed auditors, representatives from bureaus and a spokesman for the profession. In the examination we have used telephone interviews with questions based on our operationalization. From our analyse we came to following conclusion: All three levels use strategies in the process to reduce the expectation gap, but not to all interests and not in the same range. We can se a common denominator for the strategies that are used by the levels, they are built on communication. The difference between them is that they take way thru different communication channels. Examples of communication channels are commission letters and oral communication. / Förväntningsgapet är definitionen på skillnaden mellan vad intressenterna förväntar sig av revisorn och vad revisorn i själva verket tillhandahåller. Det har utförts en rad studier gällande förväntningsgapet och generellt pekar de på existensen av ett förväntningsgap. Vi vill i vår uppsats upptäcka och se hur strategier används i arbetet mot att reducera förväntningsgapet utifrån tre nivåer. Nivåerna vi behandlar är revisorer, revisionsbyråer och professionen. Vi har valt att undersöka de tre nivåernas strategier för att reducera gapet till följande tre intressentgrupper, ägare, kreditgivare och ledning/styrelse. Syftet med vår uppsats är att skapa förståelse för hur revisorn, revisionsbyrån och professionen använder sig av strategier för att reducera förväntningsgapet till intressenterna. Med existerande teorier som grund har vi tolkat och utvecklat en egen teori för vilka tänkbara strategier som kan användas av de tre nivåerna. Vi har intervjuat revisorer, representanter från byråer och en talesman för professionen. Vi har i undersökningen använt oss av telefonintervjuer med frågor baserade på vår operationalisering. Utifrån vår analys kom vi fram till följande: alla tre nivåer använder sig av strategier för att reducera förväntningsgapet, men inte till alla intressenter och inte i lika stor omfattning. Vi kan se en gemensam nämnare för strategierna som idag används av de tre nivåerna, nämligen att de bygger på kommunikation. Skillnaden mellan de är att de sker via olika kommunikationskanaler. Exempel på kommunikationskanaler är uppdragsbrev och muntlig kommunikation.

In this thesis I describe my research activities and results of the last 4 years. I also provide an outlook and guidelines on how to proceed with our project, that we named SEDNS - Security-Enhanced Domain Name System. This project’s ambitions are to complement DNS, the Domain Name System, in a way that allows us to keep using it in the future. The main reason for this strategy is, that it has proven to be difficult to change any part of the Internet infrastructure, such as parts of the protocols stack or well established Internet authorities, like ICANN or IANA. The main problems of DNS are twofold. (1) The DNS protocol does not contain any measures to prevent data from being tampered with. (2) Furthermore, it is difficult to configure DNS correctly since most of the configuration is done within the DNS data itself, e.g., delegating authority. It is well known that DNS problems lead to reduced availability of Internet-based services in many different ways. In this thesis, I present four main results. All of them contribute to improvements and deeper understanding of DNS’ dependability issues. First, I discuss, how well established cryptographic tools can be used to enhance DNS’ security without getting into the same problems that prevent DNSSEC from being globally deployed. These problems are explained as well. This is an important topic for the Internet and DNS community, since at the moment most of the protocol improvements are connected to DNSSEC. Second, I thoroughly discuss the technique that was used in the recent years to overcome any problems related to client-server architectures, i.e., peer-to-peer systems. Such solutions have been proposed to improve DNS’ availability and reduce configuration effort. I show, that those systems do not keep up with the expectations, neither as client side tools nor as server infrastructure replacement. To reach this conclusion, a novel DHT scheme has been developed. The evaluation of it is shown as well. Third, results of our DNS data mining show that it is useful to improve the quality of DNS data and therefore, to protect clients from malicious or erroneous information. And fourth, an outlook is presented, which combines all the results of the first three points to suggest an architecture that indeed can improve our supply with DNS data, omitting the shortcomings of the classical client-server-architecture and its peer-to-peer replacements. Note, that although the development of future DNS standards and protocols is subject to political struggle, e.g., on whether or not an international organization should maintain the root zone instead of the USA, this thesis focuses only on technical aspects. / In dieser Dissertation beschreibe ich meine Forschungsaktivitäten und Ergebnisse der letzten 4 Jahre. Ich gebe auch einen Ausblick und Hinweise, wie unser Project, das wir SEDNS - Security-Enhanced Domain Name System genannt haben, fortgesetzt werden sollte. Die Ambitionen dieses Projektes sind, DNS, das Domain Name System, zu in einer Art und Weise zu erweitern, die es uns erlauben soll, dieses System auch in der Zukunft weiter zu benutzen. Der Hauptgrund für diese Strategie ist, dass es sich in der Vergangenheit als schwierig erwiesen hat, Teile der Internet-Infrastruktur, wie zum Beispiel Teile des Protokollstapels oder gut etablierte Internet-Behörden wie ICANN oder IANA, zu ändern bzw. auszutauschen. Daher wollen wir nicht versuchen, DNS komplett zu ersetzen. DNS hat zwei Hauptprobleme: (1) Das DNS Protokoll bietet keinerlei Möglichkeiten, Daten vor Verfälschung zu schützen, und (2) es ist schwierig, DNS korrekt zu konfigurieren, weil ein Großteil der Konfiguration direkt innerhalb der DNS Daten selbst stattfindet, wie zum Beispiel die Delegation von Verantwortungsbereichen, und diese oft nicht global konsistent und korrekt sind. Diese Probleme sind umso bedeutender, weil es allgemein bekannt ist, dass DNS Probleme auf verschiedene Art und Weisen zu reduzierter Verfügbarkeit von wichtigen Internet-basierten Diensten führen. In dieser Arbeit präsentiere ich vier Hauptergebnisse. Zuerst diskutiere ich, wie gut etablierte kryptographische Werkzeuge benutzt werden können um die Sicherheit von DNS zu verbessern, ohne dabei auf dieselben Probleme zu stoßen, die DNSSEC davon abhalten, weltweit benutzt zu werden. Diese Probleme werden dabei erläutert. Es handelt sich dabei um ein wichtiges Thema für die Internet- und DNS-Community, weil im Moment die meisten Weiterentwicklungen des DNS Protokolls mit DNSSEC zusammenhängen. Als zweites diskutiere ich im Detail die Technik, die in den vergangenen Jahren benutzt wurde um Probleme beliebiger Client-Server Anwendungen zu überwinden: Peer-to-Peer Systeme. Derartige Lösungen wurden vorgeschlagen, um DNS' Verfügbarkeit zu verbessern und Konfigurationsaufwand zu reduzieren. Ich zeige allerdings, dass solche Lösungen nicht die in sie gesetzten Erwartungen erfüllen, weder als Client-seitige Tools noch als Ersatz für die Server-Infrastruktur. Um diesen Schluss zu ziehen, wurde ein neues, auf die Bedürfnisse von DNS zugeschnittenes DHT Schema entwickelt und evaluiert im Vergleich zu DNS und existierenden Systemen. Als drittes werden DNS Data Mining Ergebnisse präsentiert, die zeigen, wie sinnvoll es ist, die Qualität der DNS Daten zu verbessern, und somit Clients vor bösartigen oder fehlerhaften Informationen zu schützen. Als viertes wird ein Ausblick präsentiert, der die Ergebnisse der vorherigen drei Punkte kombiniert und eine Architektur vorschlägt, die unsere Versorgung mit DNS Daten tatsächlich verbessern kann und die Nachteile der klassischen Client-Server-Architektur und ihrer Peer-to-Peer Nachfolger vermeidet. Zu beachten ist, dass obwohl die Entwicklung zukünftiger DNS Standards und Protokolle Gegenstand politischer Konflikte ist, z.B. darüber ob anstelle der USA eine internationale Organisation die Root-Zone verwalten sollte, diese Arbeit nur auf die technischen Aspekte ausgerichtet ist.

Made available in DSpace on 2015-05-14T12:09:19Z (GMT). No. of bitstreams: 1 parte1.pdf: 2251690 bytes, checksum: 95ea9b80e4e6b97eecd2712f040514b9 (MD5) Previous issue date: 2009-09-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Due to the intensity of its use, the motorized transport has become one of the biggest urban problems, because of the negative impacts caused on this environment. As the population grows, the need to move belongings and people also swells. Although to contribute decisively to the development of economic activities, the intense use of inadequate transportation has grown the social inequities, becoming a big challenge to urban managers committed to sustainability. In order to produce knowledge to support politics formulation to sustainable urban mobility, this work was based on an extensive literature search, in which it was possible to analyze the negative impacts arising from the urban transport and some measures to reduce those impacts currently adopted in developed countries. Based on this analysis, it was developed a field research, where the object of study was some selected measures, which considered potentially viable for developing countries to assess the degree of acceptance and awareness of drivers of the city of João Pessoa, capital of the state of Paraíba (Brazil). Among other findings, the survey revealed that in João Pessoa, the field is open for the adoption of measures to reduce impacts of urban transport. / Devido à intensidade de seu uso, o transporte motorizado vem se tornando um dos maiores problemas do meio urbano, pelos impactos negativos causados nesse ambiente. À medida que a população cresce, a necessidade de deslocamento de bens e pessoas também se avoluma e, apesar de contribuir de forma decisiva para o desenvolvimento das atividades econômicas, a intensa utilização de transporte inadequado tem feito crescer as iniqüidades sociais, passando a ser considerado um grande desafio aos gestores urbanos comprometidos com a sustentabilidade. Com o objetivo de produzir subsídios para formulação de políticas sustentáveis para a mobilidade urbana, este trabalho baseou-se em uma ampla pesquisa bibliográfica, na qual foi possível analisar os impactos negativos oriundos do transporte urbano e algumas medidas de redução desses impactos adotadas atualmente em países desenvolvidos. Com base nessas análises, foi desenvolvida uma pesquisa de campo, tendo como objeto de estudo algumas medidas selecionadas, consideradas potencialmente viáveis para países em desenvolvimento, para aferir o grau de aceitação e a percepção dos motoristas da cidade de João Pessoa, capital do Estado da Paraíba (Brasil). Entre outras conclusões, a pesquisa revelou que em João Pessoa, o campo está aberto para a adoção de medidas de redução dos impactos do transporte urbano.

Orientador: Jefferson Sidney Camacho / Banca: Rogério de Oliveira Rodrigues / Banca: Luiz Roberto Prudêncio Júnior / Resumo: O principal objetivo do trabalho foi desenvolver o estudo de ligações diretas entre paredes de blocos de concreto em escala real e reduzida 1A. Foram realizados ensaios de resistência à compressão axial e medidas as deformações em blocos, prismas e paredes nas duas escalas. Também foram montadas paredes em forma de H assentadas sobre bases de concreto armado. Estas foram construídas de 2 formas: na primeira, chamada de PRl, foram construídas 3 (três) unidades de modo que a parede central não possuísse apoio em sua base, com isso, todo o carregamento aplicado foi transferido para as abas. Na segunda forma, chamada PH2, foram montadas 3 (três) unidades, e ,nestas, a parede central ficou apoiada em sua base, dessa maneira, observou-se os efeitos de transferência de carga entre paredes, simulando uma estrutura real, onde geralmente todas as paredes da edificação são apoiadas em outras paredes ou em vigas baldrames. Na confecção dos corpos-de-prova, nas duas escalas em estudo, foi empregada uma argamassa industrializada usada comercialmente. O carregamento foi introduzido de forma centrada, e as deformações foram medidas através de relógios comparadores e de extensômetros elétricos. Para a análise dos resultados foram empregados testes estatísticos, validando estatisticamente as conclusões. Também foi empregada uma análise através de elementos finitos, simulando os ensaios experimentais realizados, comparando-se os resultados e readequando o modelo numérico. Os resultados obtidos permitiram uma avaliação da eficiência dos modelos numéricos empregados e os ajustes necessários nos mesmos, o entendimento da forma de transferência das ações verticais entre as paredes interligadas e as correlações entre as escalas estudadas. / Abstract: The main objective ofthis research was to develop a study of direct bond (stretcher bond) connections between walls of concrete blocks in real and 1:4 small-scale. In order to know the mechanical properties, it was accomplished shear and axial strength tests where it was also measured the strain in blocks, prisms and walls for both scales. It was executed walls in the "H" form supported by reinforced concrete base. These walls were done in two different ways, the first was called PRI, (with 3 specimens) it had no support in its central wall base, thus forcing that alI the load imposed to it was transferred to the lateral walIs throughout the connections. The second kind, which was called PH2, with also 3 specimens, was entirely support in its base. This was done in order to observe the load transference effects among walls simulating conventional structures, where all the walls are support over other walls or foundation beams. The specimens in both scales were made using industrialized mortar commercially used. The load was centralized imposed and strains were measurements by electrical displacement gages and strain gages. Statistical tests were used in the result analysis, statistically validating the conclusions. A finite element analysis was also used attempting to simulate the accomplished experimental tests, being this analytical model compared to the experimental results and then, by retrofitting the numerical analysis approaching their results. The obtained results allowed: an evaluation of the efficiency of the numeric models employed and the necessity of retrofitting the analysis; the comprehension in the way of transference of the vertical actions between the interlinked walls; and the correlations among the studied scales. / Mestre

Cette thèse s'inscrit dans la thématique du stockage de l'hydrogène sous forme d'hydrure métallique. Pour pallier aux coûts importants des éléments utilisés pour l'élaboration des matériaux hydrurables, il est possible d'utiliser des alliages de pureté moindre comme précurseurs. Cela implique la présence d'éléments supplémentaires dans matériaux. Le matériau étudié appartient à la famille des composés intermétalliques Ti-V-Fe de structure cubique centrée. Cette structure est connue pour donner de fortes capacités réversibles d'absorption d'hydrogène durant une utilisation dans des conditions proches de l’ambiant. Grâce à une modélisation des principaux paramètres des hydrures formés à partir de ces alliages, il est apparu que le composé Ti15V71Fe14 présente des pressions d’équilibre intéressantes à température ambiante. Toutes les propriétés de ce matériau de référence ont été mesurées par diffraction des rayons X, microsonde de Castaing, microscopie à balayage électronique et banc d’hydruration. Une petite quantité des éléments d’addition est ajoutée individuellement puis ensemble dans la composition du matériau référent. Les échantillons sont analysés et les résultats sont comparés à ceux obtenus avec le référent. Il apparait que l’aluminium forme une solution solide de structure cubique centrée simple et améliore la capacité d’absorption du matériau référent. Il en est de même pour le silicium malgré un comportement plus complexe avec l’apparition de plusieurs phases supplémentaires. En contrepartie la vitesse d’absorption de l’hydrogène dans le matériau est diminuée / This Ph.D takes place on the hydrogen storage theme in metal hydride. In order to reduce the cost of the elements used for the preparation of hydridable materials, it is possible to use lower purity alloys as precursors. The compound selected belongs to the body centered cubic family consisting of Ti, V and Fe. This structure is known to store reversibly good quantities of hydrogen in conditions close to ambient. Thanks to modeling of the main parameters, it appears that the compound Ti15V71Fe14 presents interesting equilibrium pressure at room temperature. All properties of this reference material are measured by X-ray diffraction, EPMA, scanning electron microscopy and hydriding apparatus. A small amount of alloying elements has then been added individually then together in the composition of the reference material. Samples are analyzed and the results are compared to the referent. It appears that aluminum forms a solid solution of body centered cubic structure and improves the absorption capacity of the reference material. It is the same for silicon despite more complex behavior with the formation of several additional phases. In return the absorption kinetic of the material is reduced

This thesis is about Circular Economy and sustainability through a retailer’s perspective. There has also been a focus on researching and trying to find out if the size of the retailer matters in a sustainability perspective and to achieve a Circular Economy. The research that has been made is done with a deductive approach and a qualitative method. Interviews have been held over a timeframe of a week in May 2020. Because of the pandemic, Covid-19, all of the interviews were held over telephone or email to ensure safety for all respondents, including the safety for the authors. The theory chapter has been conducted through peer-reviewed articles and literature. This chapter has then been divided into smaller parts chapters, as Circular Economy, Sustainability and Supply chain, and Triple bottom line. After the theory chapter the method in how the research have been done and why specific methods have been preferred over others. Following chapter is the empirical findings bundled together with analysis, each interview comes first separately and divided in the same way as the theory and are then compared in an analysis. The conclusion is that retailers need to continue working to become more sustainable. A way for retailers to present their work towards Circular Economy and sustainability is to be transparent and will reach consumers’ which can lead to higher reliability. There is a difference between larger and smaller retailers, it is in how the larger retailers have worked more towards incorporate Circular Economy model and sustainability in comparison to the smaller retailers.

No description available.

Reduced-speed school zones greatly improve the safety of young children commuting to and from school and provide larger gaps in traffic for children to cross the street. The main focus of this study was to determine effective methods for increasing speed compliance in reduced-speed school zones. This objective was accomplished through an in-depth literature review, a public opinion survey of Utah drivers, and an evaluation of the effects of speed monitoring displays (SMDs) in school zones. The main focus of the literature review was to determine how to increase and maintain speed limit compliance within school zones. Information about the following topics with respect to school zones was researched and compiled: traffic control devices, SMDs, law enforcement, and other speed influences. A public survey was developed and implemented to evaluate the feelings and concerns of Utah drivers with respect to school-zone safety and school-zone traffic control devices. The survey was conducted in various locations throughout the state of Utah and proved to be an effective tool. The majority of those surveyed felt there was a need to improve school-zone safety in Utah. An evaluation of SMDs in four school zones throughout the state was performed. The results concluded that the SMDs analyzed in this study proved to increase speed compliance in most cases. In some cases, the SMDs maintained their effectiveness at increasing speed compliance over time; on the other hand, others lost some of their effectiveness over time, possibly due to higher percentages of commuter traffic. For the most part, speed compliance increased as manifested by the decrease in mean speed, standard deviation, 10 mph pace range, and the percentage of vehicles exceeding the 20 mph school-zone speed limit. In summary, the results of this study suggest that a combination of effective traffic control devices, public education, and appropriate law enforcement are all necessary to improve speed-limit compliance in school zones.

Based on an analysis of challenges and enablers of circular economy (CE) practices for outdoor brands and retailers, we aim to identify which of these CE practices are best suited for the outdoor sporting goods industry. To develop the study, we used a qualitative methodology through a content analysis of 21 expert interviews. From these interviews, we derived challenges and enablers for different CE elements in the categories reduce, circulate products, circulate materials, and shift towards renewable resources. Our findings indicate trade-offs related to the high complexity and functionality of many products, the juxtaposition of extremely technical and less technical products, and the low product return rate as challenges, while design for durability, design for repairability, and linking the degree of circularity to product types were identified as enablers. Based on our data, we argue that among circular practices reduce should form a basis upon which other aspects can build, with durability and repairability best suited for technical outdoor gear. As our study adds an industry-specific perspective, it contributes new knowledge to the CE literature. It also helps managers with the practical implications, as we argue they should be aware of potential downsides of CE elements and thus consider carefully which of those elements can help support their overall business and sustainability strategies.