A Visual Language for Web Querying and Reasoning

As XML is increasingly being used to represent information on the Web, query and reasoning languages for such data are needed. This article argues that in contrast to the navigational approach taken in particular by XPath and XQuery, a positional approach as used in the language Xcerpt is better suited for a straightforward visual representation. The constructs of the pattern- and rule-based query language Xcerpt are introduced and it is shown how the visual representation visXcerpt renders these constructs to form a visual query language for XML

Completing Queries: Rewriting of IncompleteWeb Queries under Schema Constraints

Reactive Web systems, Web services, and Web-based publish/ subscribe systems communicate events as XML messages, and in many cases require composite event detection: it is not sufficient to react to single event messages, but events have to be considered in relation to other events that are received over time. Emphasizing language design and formal semantics, we describe the rule-based query language XChangeEQ for detecting composite events. XChangeEQ is designed to completely cover and integrate the four complementary querying dimensions: event data, event composition, temporal relationships, and event accumulation. Semantics are provided as model and fixpoint theories; while this is an established approach for rule languages, it has not been applied for event queries before

Identification of Design Principles

This report identifies those design principles for a (possibly new) query and transformation language for the Web supporting inference that are considered essential. Based upon these design principles an initial strawman is selected. Scenarios for querying the Semantic Web illustrate the design principles and their reflection in the initial strawman, i.e., a first draft of the query language to be designed and implemented by the REWERSE working group I4

A Generic Module System forWeb Rule Languages: Divide and Rule

An essential feature in practically usable programming languages is the ability to encapsulate functionality in reusable modules. Modules make large scale projects tractable by humans. For Web and Semantic Web programming, many rule-based languages, e.g. XSLT, CSS, Xcerpt, SWRL, SPARQL, and RIF Core, have evolved or are currently evolving. Rules are easy to comprehend and specify, even for non-technical users, e.g. business managers, hence easing the contributions to the Web. Unfortunately, those contributions are arguably doomed to exist in isolation as most rule languages are conceived without modularity, hence without an easy mechanism for integration and reuse. In this paper a generic module system applicable to many rule languages is presented. We demonstrate and apply our generic module system to a Datalog-like rule language, close in spirit to RIF Core. The language is gently introduced along the EU-Rent use case. Using the Reuseware Composition Framework, the module system for a concrete language can be achieved almost for free, if it adheres to the formal notions introduced in this paper

Effective and Efficient Data Access in the Versatile Web Query Language Xcerpt

Access to Web data has become an integral part of many applications and services. In the past, such data has usually been accessed through human-tailoredHTMLinterfaces.Nowadays, rich client interfaces in desktop applications or, increasingly, in browser-based clients ease data access and allow more complex client processing based on XML or RDF data retrieved throughWeb service interfaces. Convenient specifications of the data processing on the client and flexible, expressive service interfaces for data access become essential in this context.Web query languages such as XQuery, XSLT, SPARQL, or Xcerpt have been tailored specifically for such a setting: declarative and efficient access and processing ofWeb data. Xcerpt stands apart among these languages by its versatility, i.e., its ability to access not just oneWeb format but many. In this demonstration, two aspects of Xcerpt are illustrated in detail: The first part of the demonstration focuses on Xcerpt’s pattern matching constructs and rules to enable effective and versatile data access. It uses a concrete practical use case from bibliography management to illustrate these language features. Xcerpt’s visual companion language visXcerpt is used to provide an intuitive interface to both data and queries. The second part of the demonstration shows recent advancements in Xcerpt’s implementation focusing on experimental evaluation of recent complexity results and optimization techniques, as well as scalability over a number of usage scenarios and input sizes

Regular Rooted Graph Grammars

In dieser Arbeit wir ein pragmatischer Ansatz zur Typisierung, statischen Analyse und Optimierung von Web-Anfragespachen, speziell Xcerpt, untersucht. Pragmatisch ist der Ansatz in dem Sinne, dass dem Benutzer keinerlei Einschränkungen aus Entscheidbarkeits- oder Effizienzgründen auf modellierbare Typen gestellt werden. Effizienz und Entscheidbarkeit werden stattdessen, falls nötig, durch Vergröberungen bei der Typprüfung erkauft. Eine Typsprache zur Typisierung von Graph-strukturierten Daten im Web wird eingeführt. Modellierbare Graphen sind so genannte gewurzelte Graphen, welche aus einem Spannbaum und Querreferenzen aufgebaut sind. Die Typsprache basiert auf reguläre Baum Grammatiken, welche um typisierte Referenzen erweitert wurde. Neben wie im Web mit XML üblichen geordneten strukturierten Daten, sind auch ungeordnete Daten, wie etwa in Xcerpt oder RDF üblich, modellierbar. Der dazu verwendete Ansatz---ungeordnete Interpretation Regulärer Ausdrücke---ist neu. Eine operationale Semantik für geordnete wie ungeordnete Typen wird auf Basis spezialisierter Baumautomaten und sog. Counting Constraints (welche wiederum auf presburgerarithmetische Ausdrücke) basieren. Es wird ferner statische Typ-Prüfung und -Inferenz von Xcerpt Anfrage- und Konstrukttermen, wie auch Optimierung von Xcerpt Anfragen auf Basis von Typinformation eingeführt.This thesis investigates a pragmatic approach to typing, static analysis and static optimization of Web query languages, in special the Web query language Xcerpt. The approach is pragmatic in the sense, that no restriction on the types are made for decidability or efficiency reasons, instead precision is given up if necessary. Pragmatics on the dynamic side means to use types not only to ensure validity of objects operating on, but also influencing query selection based on types. A typing language for typing of graph structured data on the Web is introduced. The Graphs in mind are based on spanning trees with references, the typing languages is based on regular tree grammars with typed reference extensions. Beside ordered data in the spirit of XML, unordered data (i.e. in the spirit of the Xcerpt data model or RDF) can be modelled using regular expressions under unordered interpretation – this approach is new. An operational semantics for ordered and unordered types is given based on specialized regular tree automata and counting constraints (them again based on Presburger arithmetic formulae). Static type checking of Xcerpt query and construct terms is introduced, as well as optimization of Xcerpt query terms based on schema information

Modular Web Queries — From Rules to Stores

Even with all the progress in Semantic technology, accessing Web data remains a challenging issue with new Web query languages and approaches appearing regularly. Yet most of these languages, including W3C approaches such as XQuery and SPARQL, do little to cope with the explosion of the data size and schemata diversity and richness on the Web. In this paper we propose a straightforward step toward the improvement of this situation that is simple to realize and yet effective: Advanced module systems that make partitioning of (a) the evaluation and (b) the conceptual design of complex Web queries possible. They provide the query programmer with a powerful, but easy to use high-level abstraction for packaging, encapsulating, and reusing conceptually related parts (in our case, rules) of a Web query. The proposed module system combines ease of use thanks to a simple core concept, the partitioning of rules and their consequences in flexible “stores”, with ease of deployment thanks to a reduction semantics. We focus on extending the rule-based Semantic Web query language Xcerpt with such a module system though the same approach can be applied to other (rule-based) languages as well

STUCK IN A MOMENT: TONIC IMMOBILITY PREDICTS POOR QUALITY OF LIFE IN TREATED PTSD PATIENTS

Background: Posttraumatic stress disorder (PTSD) is a prevalent and disabling multisystem disorder, with significant physical and psychiatric morbidity and poor quality of life (QOL). Although peritraumatic reactions - tonic immobility and dissociation - are established predictors of PTSD severity and development, there is a dearth of investigation assessing the impact of peritraumatic reactions on QOL of PTSD patients. Quality of life has become increasingly important in health care and research as a reliable outcome measure. It comprises psychological, physical, social and environmental domains, providing important information about the impact of diseases on patient\u27s life. This study aims to investigate the impact of peritraumatic tonic immobility and peritraumatic dissociation on QOL of PTSD civilian outpatients. Subjects and methods: It is a cross-sectional study of 50 victims of urban violence with current PTSD, recruited in a specialized outpatient clinic. Instruments used were: Structured Clinical Interview IV, Peritraumatic Dissociative Experiences Questionnaire, Tonic Immobility Scale and WHOQOL-BREF (psychological, physical, social and environmental domains). Linear regression models were fitted to evaluate the impact of peritraumatic reactions - tonic immobility and dissociation - on WHOQOL-BREF scores. We controlled for sex as potential confounding. Results: The severity of peritraumatic tonic immobility negatively impacted on psychological and environment domains of quality of life. For each additional point on the Tonic Immobility Scale, there was a decreased of 0.8 points on the scores of these domains of WHOQOL-BREF. Neither the peritraumatic reactions showed effects on physical nor social domains. Possible limitations of this study include cross-sectional design, relatively small sample size of tertiary center outpatients and recall bias. Conclusions: Peritraumatic tonic immobility is related to poor quality of life, adding new insights about the relationship between this immobility reaction and PTSD

Leptogenesis and low-energy phases

In supersymmetric models, the CP asymmetry produced in the decay of the lightest right-handed neutrino, $\equiv epsilon$, can be written as a function of weak scale parameters. We introduce a way of separating epsilon into contributions from the various weak-scale phases, and study the contribution of potentially measurable neutrino phases to leptogenesis. We find that the Majorana phase phi', which could have observable effects on neutrinoless double beta decay, is important for epsilon unless there are cancellations among phases. If the phase delta can be measured at a neutrino factory, then it contributes significantly to epsilon over much of parameter space.Comment: amplified discussion, minor comments added (33 pages, 3 figures

From weak-scale observables to leptogenesis

Thermal leptogenesis is an attractive mechanism for generating the baryon asymmetry of the Universe. However, in supersymmetric models, the parameter space is severely restricted by the gravitino bound on the reheat temperature $T_{RH}$. For hierarchical light neutrino masses, it is shown that thermal leptogenesis {\it can} work when $T_{RH} \sim 10^{9}$ GeV. The low-energy observable consequences of this scenario are $BR(\tau \to \ell \gamma) \sim 10^{-8} - 10^{-9}$. For higher $T_{RH}$, thermal leptogenesis works in a larger area of parameter space, whose observable consequences are more ambiguous. A parametrisation of the seesaw in terms of weak-scale inputs is used, so the results are independent of the texture chosen for the GUT-scale Yukawa matrices.Comment: a few references adde