Cette thèse étudie deux aspects d'interaction entre deux joueurs dans le modèle du calcul et de la communication quantique.Premièrement, elle étudie deux primitives cryptographiques quantiques, des briques de base pour construire des protocoles cryptographiques complexes entre deux joueurs, comme par exemple un protocole d'identification. La première primitive est la ``mise en gage quantique". Cette primitive ne peut pas être réalisée de manière inconditionnellement sûre, mais il possible d'avoir une sécurité lorsque les deux parties sont soumis à certaines contraintes additionnelles. Nous étudions cette primitive dans le cas où les deux joueurs sont limités à l'utilisation d'états et d'opération gaussiennes, un sous-ensemble de la physique quantique central en optique, donc parfaitement adapté pour la communication via fibres optiques. Nous montrons que cette restriction ne permet malheureusement pas la réalisation de la mise en gage sûre. Pour parvenir à ce résultat, nous introduisons la notion de purification intrinsèque, qui permet de contourner l'utilisation du théorème de Uhlman, en particulier dans le cas gaussien. Nous examinons ensuite une primitive cryptographique plus faible, le ``tirage faible à pile ou face'', dans le modèle standard du calcul quantique. Carlos Mochon a donné une preuve d'existence d'un tel protocole avec un biais arbitrairement petit. Nous donnons une interprétation claire de sa preuve, ce qui nous permet de la simplifier et de la raccourcir grandement.La seconde partie de cette thèse concerne l'étude de méthodes pour prouver des bornes inférieures dans le modèle de la complexité en requête. Il s'agit d'un modèle de complexité central en calcul quantique dans lequel de nombreux résultats majeurs ont été obtenus. Dans ce modèle, un algorithme ne peut accéder à l'entrée uniquement en effectuant des requêtes sur chacun des bits de l'entrée. Nous considérons une extension de ce modèle dans lequel un algorithme ne calcule pas une fonction, mais doit générer un état quantique. Cette généralisation nous permet de comparer les différentes méthodes pour prouver des bornes inférieures dans ce modèle. Nous montrons d'abord que la méthode par adversaire ``multiplicative" est plus forte que la méthode ``additive". Nous montrons ensuite une réduction de la méthode polynomiale à la méthode multiplicative, ce qui permet de conclure à la supériorité de la méthode par adversaire multiplicative sur toutes les autres méthodes. Les méthodes par adversaires sont en revanche souvent difficiles à utiliser car elles nécessite le calcul de normes de matrices de très grandes tailles. Nous montrons comment l'étude des symétries d'un problème simplifie grandement ces calculs. Enfin, nous appliquons ces formules pour prouver la borne inférieure optimale du problème INDEX-ERASURE un problème de génération d'état quantique lié au célèbre problème GRAPH-ISOMORPHISM. / This dissertation studies two different aspects of two-player interaction in the model of quantum communication and quantum computation.First, we study two cryptographic primitives, that are used as basic blocks to construct sophisticated cryptographic protocols between two players, e.g. identification protocols. The first primitive is ``quantum bit commitment''. This primitive cannot be done in an unconditionally secure way. However, security can be obtained by restraining the power of the two players. We study this primitive when the two players can only create quantum Gaussian states and perform Gaussian operations. These operations are a subset of what is allowed by quantum physics, and plays a central role in quantum optics. Hence, it is an accurate model of communication through optical fibers. We show that unfortunately this restriction does not allow secure bit commitment. The proof of this result is based on the notion of ``intrinsic purification'' that we introduce to circumvent the use of Uhlman's theorem when the quantum states are Gaussian. We then examine a weaker primitive, ``quantum weak coin flipping'', in the standard model of quantum computation. Mochon has showed that there exists such a protocol with arbitrarily small bias. We give a clear and meaningful interpretation of his proof. That allows us to present a drastically shorter and simplified proof.The second part of the dissertation deals with different methods of proving lower bounds on the quantum query complexity. This is a very important model in quantum complexity in which numerous results have been proved. In this model, an algorithm has restricted access to the input: it can only query individual bits. We consider a generalization of the standard model, where an algorithm does not compute a classical function, but generates a quantum state. This generalization allows us to compare the strength of the different methods used to prove lower bounds in this model. We first prove that the ``multiplicative adversary method'' is stronger than the ``additive adversary method''. We then show a reduction from the ``polynomial method'' to the multiplicative adversary method. Hence, we prove that the multiplicative adversary method is the strongest one. Adversary methods are usually difficult to use since they involve the computation of norms of matrices with very large size. We show how studying the symmetries of a problem can largely simplify these computations. Last, using these principles we prove the tight lower bound of the INDEX-ERASURE problem. This a quantum state generation problem that has links with the famous GRAPH-ISOMORPHISM problem.

Das Münzkabinett ist – obwohl zentral im Georgenbau am Residenzschloss untergebracht – eines der weniger intensiv besuchten Museen der Staatlichen Kunstsammlungen Dresden.1 Dies liegt vor allem an der durch laufende Baumaßnahmen bedingten Begrenztheit der Präsentationsräume. Während die 30.000 Bände umfassende Spezialbibliothek und der Studiensaal interessierten Fachbesuchern Detailstudien ermöglichen, steht der Sammlungspräsentation aufgrund des Umbaus der Ausstellungsräume nur ein kleines Rondell im Hausmannsturm des Residenzschlosses zur Verfügung. (...)

The principal objective of this thesis is the comprehension of students' mental processes while solving verbal math problems about money. There searchis focused on pupils in the first stage of primary school and in particular verbal math problems, in which nominal value of coins, quantity of coins and their total particular verbal math problems, in which nominal value of coins, quantity of coins and their total sum play a key role. There fore, the objective of this diploma thesis is to lay out classify mony-related exprecises in thee currently used lies of elementary school mathematics text books for grade. The theoretical part consist of demarcation of early school age, a certain number of fanticipate dacts by RVP ZV for the first and second educational period, numeracy, literacy, verbal math problems, various strategies on how to solve such problems, basic is sues pipils encounter whilw solving those problems, coments on the topic of verbal math problems which appear in theree volume soft text books in tended for primary schools (Prodos, Taktic, H-mat). Their division into three types (a total sum of coins, nominal value of coins and number of coins) and their mutual comparision. The goal of the practial part is to analyse thought processes of and grade pupils when solving word problems about...

There is little solid research that explores counterinsurgency practices against the Revolutionary Armed Forces of Colombia (FARC), not only from the standpoint of what is being done, but, rather, what should be done based on past COIN successes. Notable works on counterinsurgency in Colombia include the research of Tom Marks, who focused on operational strategy and tactics; Kevin Self, who professes the importance of controlling territory in defeating the FARC, by addressing the social and institutional ills within Colombia itself; and Dennis Rempe, who notes US involvement in shaping Colombia's COIN strategy. Using a comparative case study model, this thesis provides an analysis of Colombia?s counterinsurgency (COIN) strategies and tactics through the lens of successful and unsuccessful COIN operations in Iraq, Algeria, Malaya, South Vietnam, Thailand, Algeria and El Salvador over the course of the 20th and early 21st centuries. After all, no matter how successful a COIN force is militarily, their accomplishments will ultimately be fruitless if the conditions which fuel insurgency remains present. This paper begins by providing the historical context for the conditions which shaped the Colombian social order, which led to the revolutionary movement. It then follows the growth of the FARC, examining that organization?s strengths and weaknesses. The FARC is contrasted by outlining recent COIN transformation efforts within the Colombian government, to include little acknowledged failures and successes, strengths and weaknesses. An important focus is placed on Colombian President Alvaro Uribe Velez? Democratic Security Policy as the model for Colombia?s current COIN efforts. After next examining various ongoing factors contributing to the Colombian insurgency?to include institutional failures, illicit funding and the problem of paramilitary groups?this thesis examines past COIN efforts by other governments. Finally, after applying lessons learned from thee past COIN efforts?cross-referencing historically successful and unsuccessful tactics with tactics used and not used by Bogota in its fight against the FARC?I provide recommendations to the government of Colombia (GOC) on how to improve its COIN efforts. Although it is important to look at this problem set from an external standpoint, we must still factor in internal factors that have limited Colombia?s ability to emerge victorious, such as allowing porous borders, airspace and coastlines; placing a priority on killing or capturing the enemy and not on engaging the population; and the primacy of military direction of counterinsurgency; disregard of basic human rights; an insufficient judiciary structure; failure to halt financial support mechanisms; and the lack of an outlet for political inclusion . From this vantage point, we will be able to see that these elements?when properly implemented?have proven successful over time and may enhance GOC success and ultimately result in victory over the insurgency that has plagued their country for 40+ years

This study examines the phenomenon of abusive violence (AV) in the context of the American Post-9/11 Counter-terrorism and Counter-insurgency campaigns. Previous research into atrocities by states and their agents has largely come from examinations of totalitarian regimes with well-developed torture and assassination institutions. The mechanisms influencing willingness to do harm have been examined in experimental studies of obedience to authority and the influences of deindividuation, dehumanization, context and system. This study used Interpretive Phenomenological Analysis (IPA) to examine the lived experience of AV reported by fourteen American military and intelligence veterans. Participants were AV observers, objectors, or abusers. Subjects described why AV appeared sensible at the time, how methods of violence were selected, and what sense they made of their experiences after the fact. Accounts revealed the roles that frustration, fear, anger and mission pressure played to prompt acts of AV that ranged from the petty to heinous. Much of the AV was tied to a shift in mission view from macro strategic aims of CT and COIN to individual and small group survival. Routine hazing punishment soldiers received involving forced exercise and stress positions made similar acts inflicted on detainees unrecognizable as abusive. Overt and implied permissiveness from military superiors enabled AV extending to torture, and extra-judicial killings. Attempting to overcome feelings of vulnerability, powerlessness and rage, subjects enacted communal punishment through indiscriminate beatings and shooting. Participants committed AV to amuse themselves and humiliate their enemies; some killed detainees to force confessions from others, conceal misdeeds, and avoid routine paperwork. Participants realized that AV practices were unnecessary, counter-productive, and self-damaging. Several reduced or halted their AV as a result. The lived experience of AV left most respondents feeling guilt, shame, and inadequacy, whether they committed abuse or failed to stop it.