Application of the Asymptotic Iteration Method to a Perturbed Coulomb Model

We show that the asymptotic iteration method converges and yields accurate energies for a perturbed Coulomb model. We also discuss alternative perturbation approaches to that model.Comment: 9 pages, 2 figures, 1 tabl

Multilingual media components directly embeddable in open educational resources in science and technology

The use and reuse of OER (Open Educational Resources) depends on several conditions. Amongst others, the richness of their metadata, their granularity and the languages ​​in which they are made available. This work aims to facilitate efficient production of graphical and language-neutral components. It is assumed that the STEM areas (Science, Technology, Engeneering and Mathematics) share a common mathematical language and, more intuitively, an iconographic approach linked to the structures that satisfy the formulas used in each case. The work is limited to these areas of knowledge, primarily as presentations and animations of very low granularity, which can be directly integrated into larger resources in any language. The overall research design consists of four stages: 1. Initially, the manual generation of presentations and animations, with no literal in any language, and very concisely focused (mainly, definitions of a single concept for each animation). Determination of common graphics primitives to differentiate the common subtasks: presentation of examples to make the concept emerge inductively, graphical construction of the definition, highlighting the generalization or instantiation steps, homogeneous use of icons for emphasising or posing a question to the observer .. . 2. Evaluation of the expressiveness and effectiveness of these resources. Currently, these resources are being presented to small groups of students. This fall begins a multilingual evaluation process on a larger scale: as part of a regular course at the UNED and as LabSpace course in the Open University. Here we attempt to clarify the appropriate assessment tools (preferably in the same graphics language) with the minimum amount of additional external comments to constitute a course in a particular language. 3. The first two stages must provide an intuitive and graphical interface of the selected formalism (mainly Discrete Mathematics and Logic). The third stage addresses the effect of changing the output device on the selection of the graphics primitives for each generic subtask. Possible variations of the graphical language will be studied in the context of HCI analyses. 4. Finally the approach addresses semi-automatic generation, via script, of these resources: from formal description of the definitions or processes (as described, for example, in OMDoc) to the production of the corresponding animation. Additionally, the injection of semantics should facilitate the link between different animations, the navigation and search of conceptual dependency and the identification of concepts that have supporting collections of resources as described. At this point, the current development of this work provides results for the first two stages described

Non-homogeneous polygonal Markov fields in the plane: graphical representations and geometry of higher order correlations

We consider polygonal Markov fields originally introduced by Arak and Surgailis (1989). Our attention is focused on fields with nodes of order two, which can be regarded as continuum ensembles of non-intersecting contours in the plane, sharing a number of features with the two-dimensional Ising model. We introduce non-homogeneous version of polygonal fields in anisotropic enviroment. For these fields we provide a class of new graphical constructions and random dynamics. These include a generalised dynamic representation, generalised and defective disagreement loop dynamics as well as a generalised contour birth and death dynamics. Next, we use these constructions as tools to obtain new exact results on the geometry of higher order correlations of polygonal Markov fields in their consistent regime.Comment: 54 page

Comment on the numerical solutions of a new coupled MKdV system (2008 Phys. Scr. 78 045008)

In this comment we point out some wrong statements in the paper by Inc and Cavlak, Phys. Scr. 78 (2008) 04500

Parsing as Reduction

We reduce phrase-representation parsing to dependency parsing. Our reduction is grounded on a new intermediate representation, "head-ordered dependency trees", shown to be isomorphic to constituent trees. By encoding order information in the dependency labels, we show that any off-the-shelf, trainable dependency parser can be used to produce constituents. When this parser is non-projective, we can perform discontinuous parsing in a very natural manner. Despite the simplicity of our approach, experiments show that the resulting parsers are on par with strong baselines, such as the Berkeley parser for English and the best single system in the SPMRL-2014 shared task. Results are particularly striking for discontinuous parsing of German, where we surpass the current state of the art by a wide margin

Dobrushin-Kotecky-Shlosman theorem for polygonal Markov fields in the plane

We consider the so-called length-interacting Arak-Surgailis polygonal Markov fields with V-shaped nodes - a continuum and isometry invariant process in the plane sharing a number of properties with the two-dimensional Ising model. For these polygonal fields we establish a low-temperature phase separation theorem in the spirit of the Dobrushin-Kotecky-Shlosman theory, with the corresponding Wulff shape deteremined to be a disk due to the rotation invariant nature of the considered model. As an important tool replacing the classical cluster expansion techniques and very well suited for our geometric setting we use a graphical construction built on contour birth and death process, following the ideas of Fernandez, Ferrari and Garcia.Comment: 59 pages, new version revised according to the referee's suggestions and now publishe

Classification of cosmological milestones

In this paper causal geodesic completeness of FLRW cosmological models is analysed in terms of generalised power expansions of the scale factor in coordinate time. The strength of the found singularities is discussed following the usual definitions due to Tipler and Krolak. It is shown that while classical cosmological models are both timelike and lightlike geodesically incomplete, certain observationally alllowed models which have been proposed recently are lightlike geodesically complete.Comment: RevTeX 4, 12 page

On Evidence-based Risk Management in Requirements Engineering

Background: The sensitivity of Requirements Engineering (RE) to the context makes it difficult to efficiently control problems therein, thus, hampering an effective risk management devoted to allow for early corrective or even preventive measures. Problem: There is still little empirical knowledge about context-specific RE phenomena which would be necessary for an effective context- sensitive risk management in RE. Goal: We propose and validate an evidence-based approach to assess risks in RE using cross-company data about problems, causes and effects. Research Method: We use survey data from 228 companies and build a probabilistic network that supports the forecast of context-specific RE phenomena. We implement this approach using spreadsheets to support a light-weight risk assessment. Results: Our results from an initial validation in 6 companies strengthen our confidence that the approach increases the awareness for individual risk factors in RE, and the feedback further allows for disseminating our approach into practice.Comment: 20 pages, submitted to 10th Software Quality Days conference, 201