A quandle is a set with a binary operation that satisfies three axioms that corresponds to the three Reidemeister moves on knot diagrams. Homology and cohomology theories of quandles were introduced in 1999 by Carter, Jelsovsky,Kamada, Langford, and Saito as a modification of the rack (co)homology theory defined by Fenn, Rourke, and Sanderson. Cocycles of the quandle (co)homology, along with quandle colorings of knot diagrams, were used to define a new invariant called the quandle cocycle invariants, defined in a state-sum form. This invariant is constructed using a finite quandle and a cocyle, and it has the advantage that it can distinguish some knots from their mirror images, and orientations of knotted surfaces. To compute the quandle cocycle invariant for a specific knot, we need to find a quandle that colors the given knot non-trivially, and find a cocycle of the quandle. It is not easy to find cocycles,since the cocycle conditions form a large, over-determined system of linear equations. At first the computations relied on cocycles found by computer calculations. We have seen significant progress in computations after Mochizuki discovered a family of 2- and 3-cocycles for dihedral and other linear Alexander quandles written by polynomial expressions. In this dissertation, following the method of the construction by Mochizuki, a variety of n-cocycles for n >̲ 2 are constructed for some Alexander quandles, given by polynomial expressions. As an application, these cocycles are used to compute the invariants for (2,n)-torus knots, twist knots and their r-twist spins. The calculations in the case of (2,n)-torus knots resulted in formulas that involved the derivative of the Alexander polynomial. Non-triviality of some quandle homology groups is also proved using these cocycles. Another application is given for tangle embeddings. The quandle cocycle invariants are used as obstructions to embedding tangles in links. The formulas for the cocycle invariants of tangles are obtained using polynomial cocycles, and by comparing the invariant values, information is obtained on which tangles do not embed in which knots. Tangles and knots in the tables are examined, and concrete examples are listed.

The object of this work is to exploit various constructions of string theory and M-theory to yield new insights into supersymmetric theories in both four and three dimensions. In 4d, we extend work on Seiberg-Witten theory to study and compute BPS spectra of the class of complete N = 2 theories. The approach we take is based on the program of geometric engineering, in which 4d theories are constructed from compactifications of type IIB strings on Calabi-Yau manifolds. In this setup, the natural candidates for BPS states are D3 branes wrapped on supersymmetric 3-cycles in the Calabi-Yau. Our study makes use of the mathematical structure of quivers, whose representation theory encodes the notion of stability of BPS particles. Except for 11 exceptional cases, all complete theories can be constructed by wrapping stacks of two M5 branes on Riemann surfaces. By exploring the connection between quivers and M5 brane theories, we develop a powerful algorithm for computing BPS spectra, and give an in-depth study of its applications. In particular, we compute BPS spectra for all asymptotically free complete theories, as well as an infinite set of conformal \(SU(2)^k\) theories with certain matter content. From here, we go on to apply the insight gained from our 4d study to 3d gauge theories. We consider the analog of the M5 brane construction in the case of 3d N = 2 theories: pairs of M5 branes wrapped on a 3-manifold. Using the ansantz of R-flow, we study 3-manifolds consisting of Riemann surfaces fibered over R. When the construction is non-singular, the resulting IR physics is described by a free abelian Chern-Simons theory. The mathematical data of a tangle captures the data of the gauge theory, and the Reidemeister equivalances on tangles correspond to dualities of physical descriptions. To obtain interacting matter, we allow singularities in the construction. By extending the tangle description to these singular cases, we find a set of generalized Reidemeister moves that capture non-trivial mirror symmetries of 3d gauge theories. These results give a geometric origin to these well-known 3d dualities. / Physics

The purpose of this thesis was to explore if there are emotional dilemmas in environmentally aware individuals, stemming from conflicts, resulting in their environmental personal transportation behaviour. This study uses the dialogic, relational interview method to explore possible conflicts in participants' personal transportation choices. The analysis seems to indicate that there is an apparent emotional tangle in individuals when confronted with possible double binds that put their environmental beliefs in conflict with other important aspects in their lives. The personal dilemmas they feel revolve around social pressures and their personal identities and leave them feeling conflicting emotions and strong amounts of guilt. The findings show the importance of reframing pro-environmental activities in ways that help negate the secondary injunctions that may people feel.

This study investigates the viability of revising The Update Framework (TUF) to be implemented on a distributed ledger called IOTA. TUF is a framework that is becoming the de facto standard for securing update systems. The design for the revised Update Framework, called TUFT, is thoroughly explained and examined. A security analysis  as well as a performance analysis are made for the proposed design and prototype respectivly. Security-wise, TUFT is determined to be more secure than the original framework. On the other hand, TUFT is shown to be slower than the original TUF, with some scalability issues due to the requirement to fetch the whole update history for a repository. To accompany a wider range of software we also introduce new features in TUFT that provide versioning and mapping. The work done shows that a distributed ledger can improve a system like TUF in regards to security, auditability, and immutability. In summary, the proposed TUFT design is promising with its new features although it is limited performance-wise in some regards. With the updates being done to the IOTA ledger, a system like TUFT could be further improved upon to reduce the performance impact.

No description available.

Na história do pensamento geográfico há um grande equívoco na maneira pela qual é concebida a teoria do determinismo geográfico/ambiental. Isso significa que o tema tem sido tratado sob estereotipada roupagem, empobrecendo a Geografia e difamando e subestimando inúmeros geógrafos, bem como suas obras e idéias. O primeiro grande objetivo é o de demonstrar a importância histórica, científica e filosófica da idéia das influências ambientais que subjaz ao determinismo ambiental, a inevitabilidade de sua existência enquanto hipótese básica, e a impossibilidade epistemológica de se negá-la como uma hipóteses básica da Geografia, com ênfase em alguns autores rotulados de deterministas, como Hipócrates, Montesquieu, Semple e Huntington. O segundo grande objetivo é realizar uma crítica da crítica, minando algumas generalizações e equívocos dentre tantos que historicamente têm permeado o temário geográfico, e explicar o emaranhado semântico, filosófico, conceitual e epistemológico do tema das influências ambientais sobre a esfera humana, com ênfase na falsa dualidade determinismo/possibilismo. Assim, deve ser concebida como não mais que um mero prolegômeno, essencial, todavia, ao estudo da relação homem-ambiente, e em particular, ao estudo da história do pensamento geográfico, da idéia das influências ambientais e do determinismo ambiental. Ao final da pesquisa foi possível demonstrar a insustentabilidade da suposta dicotomia entre a escola determinista e a escola possibilista; a confusão conceitual, semântica e filosófica dos textos que comentam os autores deterministas; a impertinência, a leviandade e imprecisão da crítica ao determinismo, baseada mais no rótulo criado do que nas idéias em si; a riqueza de idéias de autores como Huntington e Semple, o pioneirismo possibilista de Hipócrates e Montesquieu e outros autores; a importância do modelo de modos de narrativa e dos estratagemas erísticos de Schopenhauer para a análise textual dos autores deterministas e de seus críticos, culminando com a elaboração de vinte e dois problemas essenciais de pesquisa, lançados como propostas metodológicas e epistemológicas iniciais ao estudo da história da Geografia e de suas idéias / Environmental determinism has been a controversial theme within human sciences and geography. There has been much misunderstanding and understatement concerning this fundamental explanatory hypothesis. A varied assortment of geographical works and authors have been incorrectly labeled and suffered from biased criticism and general misconceptions. The long-standing debate around environmental determinism is marked by a chaotic semantic tangle which shades its real and proper meaning. The first objective is to show the historical, philosophical and scientific importance of environmental determinism in terms of its underlying principle and hypothesis, called the idea of the environmental influences and point to its relevance as a craddle of modern geography and as valid approach to the man-milieu relationships.The second objective is to lauch a counter-criticism on those who irresponsibly dismissed environmental determinism without recognizing its underlying and unavoidable basic hypothesis and who did not read the labeled works in full. Criticism has been frequently incomplete, biased, crude, distorted, unscientific, politically oriented or naïve. The third objective is to disentangle the semantic, epistemologic and philosophic traps that threaten any attempt of covering the theme in full perspective and detail. The fourth objective is to analyse some environmentalists, such as Semple and Huntington, in order to deny the wrong labels attached to them. The fifth objective was to deconstruct the false determinism/possibilism dualism and to present a new way of interpreting this issue. The last objective was to bring a preliminary discussion of the literature of the theme, a short history of environmental ideas from the Greeks to the modern geography in the United States. After a careful analysis some myths were proven incorrect, or misleading and inaccurate at best, and as a final evaluation, twenty-one epistemological and methodological devices were listed as a contribution to the research in history of geography.

Na história do pensamento geográfico há um grande equívoco na maneira pela qual é concebida a teoria do determinismo geográfico/ambiental. Isso significa que o tema tem sido tratado sob estereotipada roupagem, empobrecendo a Geografia e difamando e subestimando inúmeros geógrafos, bem como suas obras e idéias. O primeiro grande objetivo é o de demonstrar a importância histórica, científica e filosófica da idéia das influências ambientais que subjaz ao determinismo ambiental, a inevitabilidade de sua existência enquanto hipótese básica, e a impossibilidade epistemológica de se negá-la como uma hipóteses básica da Geografia, com ênfase em alguns autores rotulados de deterministas, como Hipócrates, Montesquieu, Semple e Huntington. O segundo grande objetivo é realizar uma crítica da crítica, minando algumas generalizações e equívocos dentre tantos que historicamente têm permeado o temário geográfico, e explicar o emaranhado semântico, filosófico, conceitual e epistemológico do tema das influências ambientais sobre a esfera humana, com ênfase na falsa dualidade determinismo/possibilismo. Assim, deve ser concebida como não mais que um mero prolegômeno, essencial, todavia, ao estudo da relação homem-ambiente, e em particular, ao estudo da história do pensamento geográfico, da idéia das influências ambientais e do determinismo ambiental. Ao final da pesquisa foi possível demonstrar a insustentabilidade da suposta dicotomia entre a escola determinista e a escola possibilista; a confusão conceitual, semântica e filosófica dos textos que comentam os autores deterministas; a impertinência, a leviandade e imprecisão da crítica ao determinismo, baseada mais no rótulo criado do que nas idéias em si; a riqueza de idéias de autores como Huntington e Semple, o pioneirismo possibilista de Hipócrates e Montesquieu e outros autores; a importância do modelo de modos de narrativa e dos estratagemas erísticos de Schopenhauer para a análise textual dos autores deterministas e de seus críticos, culminando com a elaboração de vinte e dois problemas essenciais de pesquisa, lançados como propostas metodológicas e epistemológicas iniciais ao estudo da história da Geografia e de suas idéias / Environmental determinism has been a controversial theme within human sciences and geography. There has been much misunderstanding and understatement concerning this fundamental explanatory hypothesis. A varied assortment of geographical works and authors have been incorrectly labeled and suffered from biased criticism and general misconceptions. The long-standing debate around environmental determinism is marked by a chaotic semantic tangle which shades its real and proper meaning. The first objective is to show the historical, philosophical and scientific importance of environmental determinism in terms of its underlying principle and hypothesis, called the idea of the environmental influences and point to its relevance as a craddle of modern geography and as valid approach to the man-milieu relationships.The second objective is to lauch a counter-criticism on those who irresponsibly dismissed environmental determinism without recognizing its underlying and unavoidable basic hypothesis and who did not read the labeled works in full. Criticism has been frequently incomplete, biased, crude, distorted, unscientific, politically oriented or naïve. The third objective is to disentangle the semantic, epistemologic and philosophic traps that threaten any attempt of covering the theme in full perspective and detail. The fourth objective is to analyse some environmentalists, such as Semple and Huntington, in order to deny the wrong labels attached to them. The fifth objective was to deconstruct the false determinism/possibilism dualism and to present a new way of interpreting this issue. The last objective was to bring a preliminary discussion of the literature of the theme, a short history of environmental ideas from the Greeks to the modern geography in the United States. After a careful analysis some myths were proven incorrect, or misleading and inaccurate at best, and as a final evaluation, twenty-one epistemological and methodological devices were listed as a contribution to the research in history of geography.