The CorDis Corpus Mark-up and Related Issues

CorDis is a large, XML, TEI-conformant, POS-tagged, multimodal, multigenre corpus representing a significant portion of the political and media discourse on the 2003 Iraqi conflict. It was generated from different sub-corpora which had been assembled by various research groups, ranging from official transcripts of Parliamentary sessions, both in the US and the UK, to the transcripts of the Hutton Inquiry, from American and British newspaper coverage of the conflict to White House press briefings and to transcriptions of American and British TV news programmes. The heterogeneity of the data, the specificity of the genres and the diverse discourse analytical purposes of different groups had led to a wide range of coding strategies being employed to make textual and meta-textual information retrievable. The main purpose of this paper is to show the process of harmonisation and integration whereby a loose collection of texts has become a stable architecture. The TEI proved a valid instrument to achieve standardisation of mark-up. The guidelines provide for a hierarchical organisation which gives the corpus a sound structure favouring replicability and enhancing the reliability of research. In discussing some examples of the problems encountered in the annotation, we will deal with issues like consistency and re-usability, and will examine the constraints imposed on data handling by specific research objectives. Examples include the choice to code the same speakers in different ways depending on the various (institutional) roles they may assume throughout the corpus, the distinction between quotations of spoken or written discourse and quotations read aloud in the course of a spoken text, and the segmentation of portions of news according to participants interaction and use of camera/voiceover

Metastability for reversible probabilistic cellular automata with self--interaction

The problem of metastability for a stochastic dynamics with a parallel updating rule is addressed in the Freidlin--Wentzel regime, namely, finite volume, small magnetic field, and small temperature. The model is characterized by the existence of many fixed points and cyclic pairs of the zero temperature dynamics, in which the system can be trapped in its way to the stable phase. %The characterization of the metastable behavior %of a system in the context of parallel dynamics is a very difficult task, %since all the jumps in the configuration space are allowed. Our strategy is based on recent powerful approaches, not needing a complete description of the fixed points of the dynamics, but relying on few model dependent results. We compute the exit time, in the sense of logarithmic equivalence, and characterize the critical droplet that is necessarily visited by the system during its excursion from the metastable to the stable state. We need to supply two model dependent inputs: (1) the communication energy, that is the minimal energy barrier that the system must overcome to reach the stable state starting from the metastable one; (2) a recurrence property stating that for any configuration different from the metastable state there exists a path, starting from such a configuration and reaching a lower energy state, such that its maximal energy is lower than the communication energy

Linear Boltzmann dynamics in a strip with large reflective obstacles: stationary state and residence time

The presence of obstacles modify the way in which particles diffuse. In cells, for instance, it is observed that, due to the presence of macromolecules playing the role of obstacles, the mean square displacement ofbiomolecules scales as a power law with exponent smaller than one. On the other hand, different situations in grain and pedestrian dynamics in which the presence of an obstacle accelerate the dynamics are known. We focus on the time, called residence time, needed by particles to cross a strip assuming that the dynamics inside the strip follows the linear Boltzmann dynamics. We find that the residence time is not monotonic with the sizeand the location of the obstacles, since the obstacle can force those particles that eventually cross the strip to spend a smaller time in the strip itself. We focus on the case of a rectangular strip with two open sides and two reflective sides and we consider reflective obstaclea into the strip

On the Classical Model for Microwave Induced Escape from a Josephson Washboard Potential

We revisit the interpretation of earlier low temperature experiments on Josephson junctions under the influence of applied microwaves. It was claimed that these experiments unambiguously established a quantum phenomenology with discrete levels in shallow wells of the washboard potential, and macroscopic quantum tunneling. We here apply the previously developed classical theory to a direct comparison with the original experimental observations, and we show that the experimental data can be accurately represented classically. Thus, our analysis questions the necessity of the earlier quantum mechanical interpretation.Comment: 4 pages, one table, three figures. Submitted for publication on December 14, 200

Does communication enhance pedestrians transport in the dark?

We study the motion of pedestrians through an obscure tunnel where the lack of visibility hides the exits. Using a lattice model, we explore the effects of communication on the effective transport properties of the crowd of pedestrians. More precisely, we study the effect of two thresholds on the structure of the effective nonlinear diffusion coefficient. One threshold models pedestrians's communication efficiency in the dark, while the other one describes the tunnel capacity. Essentially, we note that if the evacuees show a maximum trust (leading to a fast communication), they tend to quickly find the exit and hence the collective action tends to prevent the occurrence of disasters

Correlation functions by Cluster Variation Method for Ising model with NN, NNN and Plaquette interactions

We consider the procedure for calculating the pair correlation function in the context of the Cluster Variation Methods. As specific cases, we study the pair correlation function in the paramagnetic phase of the Ising model with nearest neighbors, next to the nearest neighbors and plaquette interactions in two and three dimensions. In presence of competing interactions, the so called disorder line separates in the paramagnetic phase a region where the correlation function has the usual exponential behavior from a region where the correlation has an oscillating exponentially damped behavior. In two dimensions, using the plaquette as the maximal cluster of the CVM approximation, we calculate the phase diagram and the disorder line for a case where a comparison is possible with results known in literature for the eight-vertex model. In three dimensions, in the CVM cube approximation, we calculate the phase diagram and the disorder line in some cases of particular interest. The relevance of our results for experimental systems like mixtures of oil, water and surfactant is also discussed.Comment: 31 pages, LaTeX file, 7 figure