Analysing change in international politics: a semiotic method of structural connotation

Processes such as internationalisation and privatisation bring along new challenges both for the conceptualisation and for the measurement of transformations of the state. This paper outlines a semiotic Method of Structural Connotation, which combines content- and network analysis, thus to model change in international politics. After an investigation of the methodical and epistemological chances and pitfalls a 5-step-toolbox is presented and illustrated with a current application: The Bologna-Process for a European Higher Education Area. -- Angesichts neuerer Entwicklungen wie Internationalisierung und Privatisierung stellen sich auch neue Herausforderungen für die Konzeptualisierung und Messung von Staatlichkeit im Wandel. In diesem Arbeitspapier wird eine semiotische Methode Struktureller Konnotation vorgestellt, die inhaltsanalytische und netzwerkanalytische Elemente zusammenführt, um den Wandel internationaler politischer Prozesse und Akteursfigurationen zu erfassen. Nach einer Betrachtung der methodischen und epistemologischen Herausforderungen und Chancen folgt ein konkreter Verfahrensvorschlag nach dem Baukastenprinzip. Am Beispiel des Bologna-Prozesses für einen Europäischen Hochschulraum wird das methodische Vorgehen Schritt für Schritt erläutert.

Pinning of polymers and interfaces by random potentials

We consider a polymer, with monomer locations modeled by the trajectory of a Markov chain, in the presence of a potential that interacts with the polymer when it visits a particular site 0. Disorder is introduced by, for example, having the interaction vary from one monomer to another, as a constant $u$ plus i.i.d. mean-0 randomness. There is a critical value of $u$ above which the polymer is pinned, placing a positive fraction of its monomers at 0 with high probability. This critical point may differ for the quenched, annealed and deterministic cases. We show that self-averaging occurs, meaning that the quenched free energy and critical point are nonrandom, off a null set. We evaluate the critical point for a deterministic interaction ($u$ without added randomness) and establish our main result that the critical point in the quenched case is strictly smaller. We show that, for every fixed $u\in\mathbb{R}$, pinning occurs at sufficiently low temperatures. If the excursion length distribution has polynomial tails and the interaction does not have a finite exponential moment, then pinning occurs for all $u\in\mathbb{R}$ at arbitrary temperature. Our results apply to other mathematically similar situations as well, such as a directed polymer that interacts with a random potential located in a one-dimensional defect, or an interface in two dimensions interacting with a random potential along a wall.Comment: Published at http://dx.doi.org/10.1214/105051606000000015 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Subgaussian concentration and rates of convergence in directed polymers

We consider directed random polymers in (d+1) dimensions with nearly gamma i.i.d. disorder. We study the partition function ZN,ω and establish exponential concentration of log ZN,ω about its mean on the subgaussian scale √N/log N . This is used to show that E[log ZN,ω] differs from N times the free energy by an amount which is also subgaussian (i.e. o(√N)), specifically O(√N/logN log log N)