Development of Use Cases, Part I

For determining requirements and constructs appropriate for a Web query language, or in fact any language, use cases are of essence. The W3C has published two sets of use cases for XML and RDF query languages. In this article, solutions for these use cases are presented using Xcerpt. a novel Web and Semantic Web query language that combines access to standard Web data such as XML documents with access to Semantic Web metadata such as RDF resource descriptions with reasoning abilities and rules familiar from logicprogramming. To the best knowledge of the authors, this is the first in depth study of how to solve use cases for accessing XML and RDF in a single language: Integrated access to data and metadata has been recognized by industry and academia as one of the key challenges in data processing for the next decade. This article is a contribution towards addressing this challenge by demonstrating along practical and recognized use cases the usefulness of reasoning abilities, rules, and semistructured query languages for accessing both data (XML) and metadata (RDF)

D7-Brane Chaotic Inflation

We analyze string-theoretic large-field inflation in the regime of spontaneously-broken supergravity with conventional moduli stabilization by fluxes and non-perturbative effects. The main ingredient is a shift-symmetric Kahler potential, supplemented by flux-induced shift symmetry breaking in the superpotential. The central technical observation is that all these features are present for D7-brane position moduli in Type IIB orientifolds, allowing for a realization of the axion monodromy proposal in a controlled string theory compactification. On the one hand, in the large complex structure regime the D7-brane position moduli inherit a shift symmetry from their mirror-dual Type IIA Wilson lines. On the other hand, the Type IIB flux superpotential generically breaks this shift symmetry and allows, by appealing to the large flux discretuum, to tune the relevant coefficients to be small. The shift-symmetric direction in D7-brane moduli space can then play the role of the inflaton: While the D7-brane circles a certain trajectory on the Calabi-Yau many times, the corresponding F-term energy density grows only very slowly, thanks to the above-mentioned tuning of the flux. Thus, the large-field inflationary trajectory can be realized in a regime where Kahler, complex structure and other brane moduli are stabilized in a conventional manner, as we demonstrate using the example of the Large Volume Scenario.Comment: 8 pages, 2 figures; v2: references adde

Psychological needs as motivators for security and privacy actions on smartphones

Much work has been conducted to investigate the obstacles that keep users from using mitigations against security and privacy threats on smartphones. By contrast, we conducted in-depth interviews (N = 19) to explore users’ motivations for voluntarily applying security and privacy actions on smartphones. Our work focuses on analyzing intrinsic motivation in terms of psychological need fulfillment. The findings from the interview study provide first insights on the salience of basic psychological needs in the context of smartphone security and privacy. They illustrate how security and privacy actions on smartphones are motivated by a variety of psychological needs, only one of them being the need for Security. We further conducted an online survey (N = 70) in which we used questionnaires on psychological need fulfillment from the literature. The online survey is a first attempt to quantify psychological need fulfillment for security and privacy actions on smartphones. Whereas the results of the interview study indicate that Security and other needs play a role as motivators for employing security and privacy actions on smartphones, the online study does not support the need for Security as an outstanding motivator. Instead, in the online study, other needs such as Keeping the meaningful, Stimulation, Autonomy, and Competence show to be rather salient as motivators for security and privacy actions. Furthermore, the mean need fulfillment for security and privacy actions is in general rather low in the online survey. We conclude that there is scope for improvement to maximize psychological need fulfillment with security and privacy actions. In order to achieve a positive user experience with security and privacy technologies on smartphones, we suggest addressing additional psychological needs, beyond the need for Security, in the design of such technologies

Survey over Existing Query and Transformation Languages

A widely acknowledged obstacle for realizing the vision of the Semantic Web is the inability of many current Semantic Web approaches to cope with data available in such diverging representation formalisms as XML, RDF, or Topic Maps. A common query language is the first step to allow transparent access to data in any of these formats. To further the understanding of the requirements and approaches proposed for query languages in the conventional as well as the Semantic Web, this report surveys a large number of query languages for accessing XML, RDF, or Topic Maps. This is the first systematic survey to consider query languages from all these areas. From the detailed survey of these query languages, a common classification scheme is derived that is useful for understanding and differentiating languages within and among all three areas

Development of Use Cases, Part I

For determining requirements and constructs appropriate for a Web query language, or in fact any language, use cases are of essence. The W3C has published two sets of use cases for XML and RDF query languages. In this article, solutions for these use cases are presented using Xcerpt. a novel Web and Semantic Web query language that combines access to standard Web data such as XML documents with access to Semantic Web metadata such as RDF resource descriptions with reasoning abilities and rules familiar from logicprogramming. To the best knowledge of the authors, this is the first in depth study of how to solve use cases for accessing XML and RDF in a single language: Integrated access to data and metadata has been recognized by industry and academia as one of the key challenges in data processing for the next decade. This article is a contribution towards addressing this challenge by demonstrating along practical and recognized use cases the usefulness of reasoning abilities, rules, and semistructured query languages for accessing both data (XML) and metadata (RDF)

Minimal and complete set of descriptors for IR-absorption spectra of liquid H2–D2 mixtures

The IR spectra of liquid hydrogen isotopologues (Q$_{2}$ = H$_{2}$, D$_{2}$, T$_{2}$, HD, HT, DT) are dominated by the interaction induced absorption. Therefore, the complexity tremendously increases with the number of different isotopologues in the sample. As we aim for a system independent calibration of IR absorption spectroscopy against all six isotopologues and three ortho–para ratios, we need a minimal and complete set of descriptors to predict the spectra and to decrease the needed calibration effort. For this, we grouped the absorption lines into three groups: absorption on monomers, phonons, and molecular dimers. In particular, molecular dimers contribute to the absolute number of absorption lines in the spectra of mixed isotopologues. To develop and test the set of descriptors, we make use of three spectra: a pure H$_{2}$ sample, a pure D$_{2}$ sample, and a mixed H$_{2}$–D$_{2}$ sample. We show a detailed analysis of these three spectra in the first and second vibrational branch in the range from 2000 cm$^{-1}$ to 9000 cm$^{-1}$. The set of descriptors found within this work can be used to identify and predict all lines in this range for liquid H$_{2}$–D$_{2}$ mixtures

Minimal and complete set of descriptors for IR-absorption spectra of liquid H2–D2 mixtures

The IR spectra of liquid hydrogen isotopologues (Q$_{2}$ = H$_{2}$, D$_{2}$, T$_{2}$, HD, HT, DT) are dominated by the interaction induced absorption. Therefore, the complexity tremendously increases with the number of different isotopologues in the sample. As we aim for a system independent calibration of IR absorption spectroscopy against all six isotopologues and three ortho–para ratios, we need a minimal and complete set of descriptors to predict the spectra and to decrease the needed calibration effort. For this, we grouped the absorption lines into three groups: absorption on monomers, phonons, and molecular dimers. In particular, molecular dimers contribute to the absolute number of absorption lines in the spectra of mixed isotopologues. To develop and test the set of descriptors, we make use of three spectra: a pure H$_{2}$ sample, a pure D$_{2}$ sample, and a mixed H$_{2}$–D$_{2}$ sample. We show a detailed analysis of these three spectra in the first and second vibrational branch in the range from 2000 cm$^{-1}$ to 9000 cm$^{-1}$. The set of descriptors found within this work can be used to identify and predict all lines in this range for liquid H$_{2}$–D$_{2}$ mixtures