Showing papers by "Johannes Kepler University of Linz published in 2011"

Differences Between Tight and Loose Cultures: A 33-Nation Study

Abstract: With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention self-guides, high regulatory strength, need for structure). This research advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.

APCluster: an R package for affinity propagation clustering.

Abstract: Summary: Affinity propagation (AP) clustering has recently gained increasing popularity in bioinformatics. AP clustering has the advantage that it allows for determining typical cluster members, the so-called exemplars. We provide an R implementation of this promising new clustering technique to account for the ubiquity of R in bioinformatics. This article introduces the package and presents an application from structural biology. Availability: The R package apcluster is available via CRAN—The Comprehensive R Archive Network: http://cran.r-project.org/web/packages/apcluster Contact: apcluster@bioinf.jku.at; bodenhofer@bioinf.jku.at

Dielectric Elastomer Generators: How Much Energy Can Be Converted?

Abstract: Dielectric elastomers are being developed as generators to harvest energy from renewable sources, such as human movements and ocean waves. We model a generator as a system of two degrees of freedom, represented on either the stress-stretch plane or the voltage-charge plane. A point in such a plane represents a state of the generator, a curve represents a path of operation, a contour represents a cycle of operation, and the area enclosed by the contour represents the energy of conversion per cycle. Each mechanism of failure is represented by a curve in the plane. The curves of all the known mechanics of failure enclose the region of allowable states. The area of this region defines the maximum energy of conversion. This study includes the following mechanisms of failure: material rupture, loss of tension, electrical breakdown, and electromechanical instability. It is found that natural rubber outperforms VHB elastomer as a generator at strains less than 15%. Furthermore, by varying material parameters, energy of conversion can be increased above 1.0 J/g.

An All‐Printed Ferroelectric Active Matrix Sensor Network Based on Only Five Functional Materials Forming a Touchless Control Interface

Abstract: An All-Printed Ferroelectric Active Matrix Sensor Network Based on Only Five Functional Materials Forming a Touchless Control Interface

The Eighth Bacteriochlorophyll Completes the Excitation Energy Funnel in the FMO Protein.

Abstract: The Fenna−Matthews−Olson (FMO) light-harvesting protein connects the outer antenna system (chlorosome/baseplate) with the reaction center complex in green sulfur bacteria. Since its first structure determination in the mid-70s, this pigment−protein complex has become an important model system to study excitation energy transfer. Recently, an additional bacteriochlorophyll a (the eighth) pigment was discovered in each subunit of this homotrimer. Our structure-based calculations of the optical properties of the FMO protein demonstrate that the eighth pigment is the linker to the baseplate, confirming recent suggestions from crystallographic studies.

The Causal Effect of Education on Health: What is the Role of Health Behaviors?

Abstract: In this paper we investigate the contribution of health related behaviors to the education gradient, using an empirical approach that addresses the endogeneity of both education and behaviors in the health production function. We apply this approach to a multi-country data set, which includes 12 European countries and has information on education, health and health behaviors for a sample of individuals aged 50. Focusing on self reported poor health as our health outcome, we find that education has a protective role both for males and females. When evaluated at the sample mean of the dependent variable, one additional year of education reduces self-reported poor health by 7.1% for females and by 3.1% for males. Health behaviors - measured by smoking, drinking, exercising and the body mass index - contribute to explaining the gradient. We find that the effects of education on smoking, drinking, exercising and eating a proper diet account for at most 23% to 45% of the entire effect of education on health, depending on gender.

Handling drifts and shifts in on-line data streams with evolving fuzzy systems

Abstract: In this paper, we present new approaches to handling drift and shift in on-line data streams with the help of evolving fuzzy systems (EFS), which are characterized by the fact that their structure (rule base and parameters) is not fixed and not pre-determined, but is extracted from data streams on-line and in an incremental manner. When dealing with so-called drifts and s hifts in data streams, one needs to take into account (1) automatic detection of drifts and shifts and (2) automatic reaction to the drifts and shifts. This is important to avoid interruptions in the learning process and downtrends in predictive accuracy. To address the first problem, we propose an approach based on the concept fuzzy rule age. The second problem is addressed by including gradual forgetting of (1) antecedent parts and (2) consequent parameters. The latter can be achieved by including a forgetting factor in the recursive local learning process of the parameters, whose value is automatically extracted based on the intensity of the shift/drift. For addressing the former problem, we introduce two alternative methods: one is based on the evolving density-based clustering (eClustering) used to form the antecedents in the eTS approach; the other is based on the automatic adaptation of the learning rate of the evolving vector quantization (eVQ) method used to form the antecedent in the FLEXFIS approach. The paper concludes with an empirical evaluation of the impact of the proposed approaches in (on-line) real-world data sets in which drifts and shifts occur.

The DOPLER meta-tool for decision-oriented variability modeling: a multiple case study

Abstract: The variability of a product line is typically defined in models. However, many existing variability modeling approaches are rigid and don't allow sufficient domain-specific adaptations. We have thus been developing a flexible and extensible approach for defining product line variability models. Its main purposes are to guide stakeholders through product derivation and to automatically generate product configurations. Our approach is supported by the DOPLER (Decision-Oriented Product Line Engineering for effective Reuse) meta-tool that allows modelers to specify the types of reusable assets, their attributes, and dependencies for their specific system and context. The aim of this paper is to investigate the suitability of our approach for different domains. More specifically, we explored two research questions regarding the implementation of variability and the utility of DOPLER for variability modeling in different domains. We conducted a multiple case study consisting of four cases in the domains of industrial automation systems and business software. In each of these case studies we analyzed variability implementation techniques. Experts from our industry partners then developed domain-specific meta-models, tool extensions, and variability models for their product lines using DOPLER. The four cases demonstrate the flexibility of the DOPLER approach and the extensibility and adaptability of the supporting meta tool.

Infrared Emitting and Photoconducting Colloidal Silver Chalcogenide Nanocrystal Quantum Dots from a Silylamide-Promoted Synthesis

Abstract: Here, we present a hot injection synthesis of colloidal Ag chalcogenide nanocrystals (Ag2Se, Ag2Te, and Ag2S) that resulted in exceptionally small nanocrystal sizes in the range between 2 and 4 nm. Ag chalcogenide nanocrystals exhibit band gap energies within the near-infrared spectral region, making these materials promising as environmentally benign alternatives to established infrared active nanocrystals containing toxic metals such as Hg, Cd, and Pb. We present Ag2Se nanocrystals in detail, giving size-tunable luminescence with quantum yields above 1.7%. The luminescence, with a decay time on the order of 130 ns, was shown to improve due to the growth of a monolayer thick ZnSe shell. Photoconductivity with a quantum efficiency of 27% was achieved by blending the Ag2Se nanocrystals with a soluble fullerene derivative. The co-injection of lithium silylamide was found to be crucial to the synthesis of Ag chalcogenide nanocrystals, which drastically increased their nucleation rate even at relatively low g...

Exotic materials for bio-organic electronics

Abstract: “Exotic” materials have become the focus of recent developments in organic electronics that envision biocompatibility, biodegradability, and sustainability for low-cost, large-volume electronic components. In this brief review, we discuss firstly the use of paper, leather, silk, hard gelatine, and bio-degradable plastics as substrates for electronic devices, and secondly smoothing agents, such as polydimethylsiloxane and aurin. Thirdly, we describe DNA and nucleobases as examples of exotic dielectrics with low dielectric losses and leakage currents as well as sufficiently high dielectric breakdown strength. Fourthly, natural, nature-inspired, and common-commodity semiconductors are presented that broaden the materials base for organic semiconductors and may inspire further work to identify semiconductors that are stable in the face of changing environmental conditions yet degradable at the end of their product lifetime. Sustainability in organic electronics, energy storage, and emerging concepts will also be reviewed briefly. Research on “exotic” organic materials may ultimately result in environmentally safe “green electronic” products.

Sodium citrate: A universal reducing agent for reduction / decoration of graphene oxide with au nanoparticles

Abstract: A facile method is proposed for the synthesis of reduced graphene oxide nanosheets (RGONS) and Au nanoparticle-reduced graphene oxide nanosheet (Au-RGONS) hybrid materials, using graphene oxide (GO) as precursor and sodium citrate as reductant and stabilizer. The resulting RGONS and Au-RGONS hybrid materials were characterized by UV-vis spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, transmission electron microscopy, and X-ray diffraction. It was found that the RGONS and Au-RGONS hybrid materials formed stable colloidal dispersions through hydrogen bonds between the residual oxygen-containing functionalities on the surface of RGONS and the hydroxyl/carboxyl groups of sodium citrate. The electrochemical responses of RGONS and Au-RGONS hybrid material-modified glassy carbon electrodes (GCE) to three kinds of biomolecules were investigated, and all of them showed a remarkable increase in electrochemical performance relative to a bare GCE.

Educational institutions and the integration of migrants

Abstract: In this paper, I study educational integration of students with migration background using data from five international student assessment studies. First, Blinder–Oaxaca decompositions are used to allow for a comparison of integration of migrant students across countries and time. In a second step, integration is related to institutional characteristics of the schooling system. Pooled, country-group and country fixed effects estimations show that time in school and early education are positively related to the integration of students with migration background. Furthermore, in the OECD countries, educational integration in science is positively related to external student assessment policies.

A twenty-first century assessment of values across the global workforce

Abstract: This article provides current Schwartz Values Survey (SVS) data from samples of business managers and professionals across 50 societies that are culturally and socioeconomically diverse. We report the society scores for SVS values dimensions for both individual- and societal-level analyses. At the individual-level, we report on the ten circumplex values sub-dimensions and two sets of values dimensions (collectivism and individualism; openness to change, conservation, self-enhancement, and self-transcendence). At the societal-level, we report on the values dimensions of embeddedness, hierarchy, mastery, affective autonomy, intellectual autonomy, egalitarianism, and harmony. For each society, we report the Cronbach’s α statistics for each values dimension scale to assess their internal consistency (reliability) as well as report interrater agreement (IRA) analyses to assess the acceptability of using aggregated individual level values scores to represent country values. We also examined whether societal development level is related to systematic variation in the measurement and importance of values. Thus, the contributions of our evaluation of the SVS values dimensions are two-fold. First, we identify the SVS dimensions that have cross-culturally internally reliable structures and within-society agreement for business professionals. Second, we report the society cultural values scores developed from the twenty-first century data that can be used as macro-level predictors in multilevel and single-level international business research.

Cube and conquer: guiding CDCL SAT solvers by lookaheads

Abstract: Satisfiability (SAT) is considered as one of the most important core technologies in formal verification and related areas. Even though there is steady progress in improving practical SAT solving, there are limits on scalability of SAT solvers. We address this issue and present a new approach, called cube-and-conquer, targeted at reducing solving time on hard instances. This two-phase approach partitions a problem into many thousands (or millions) of cubes using lookahead techniques. Afterwards, a conflict-driven solver tackles the problem, using the cubes to guide the search. On several hard competition benchmarks, our hybrid approach outperforms both lookahead and conflict-driven solvers. Moreover, because cube-and-conquer is natural to parallelize, it is a competitive alternative for solving SAT problems in parallel.

Unit Cell Structure of Crystal Polytypes in InAs and InSb Nanowires

Abstract: The atomic distances in hexagonal polytypes of III-V compound semiconductors differ from the values expected from simply a change of the stacking sequence of (111) lattice planes. While these changes were difficult to quantify so far, we accurately determine the lattice parameters of zinc blende, wurtzite, and 4H polytypes for InAs and InSb nanowires, using X-ray diffraction and transmission electron microscopy. The results are compared to density functional theory calculations. Experiment and theory show that the occurrence of hexagonal bilayers tends to stretch the distances of atomic layers parallel to the c axis and to reduce the in-plane distances compared to those in zinc blende. The change of the lattice parameters scales linearly with the hexagonality of the polytype, defined as the fraction of bilayers with hexagonal character within one unit cell.

Automatically Detecting and Tracking Inconsistencies in Software Design Models

Abstract: Software models typically contain many inconsistencies and consistency checkers help engineers find them. Even if engineers are willing to tolerate inconsistencies, they are better off knowing about their existence to avoid follow-on errors and unnecessary rework. However, current approaches do not detect or track inconsistencies fast enough. This paper presents an automated approach for detecting and tracking inconsistencies in real time (while the model changes). Engineers only need to define consistency rules-in any language-and our approach automatically identifies how model changes affect these consistency rules. It does this by observing the behavior of consistency rules to understand how they affect the model. The approach is quick, correct, scalable, fully automated, and easy to use as it does not require any special skills from the engineers using it. We evaluated the approach on 34 models with model sizes of up to 162,237 model elements and 24 types of consistency rules. Our empirical evaluation shows that our approach requires only 1.4 ms to reevaluate the consistency of the model after a change (on average); its performance is not noticeably affected by the model size and common consistency rules but only by the number of consistency rules, at the expense of a quite acceptable, linearly increasing memory consumption.

A comparison of decision modeling approaches in product lines

Abstract: It has been shown that product line engineering can significantly improve the productivity, quality and time-to-market of software development by leveraging extensive reuse Variability models are currently the most advanced approach to define, document and manage the commonalities and variabilities of reusable artifacts such as software components, requirements, test cases, etc These models provide the basis for automating the derivation of new products and are thus the key artifact to leverage the flexibility and adaptability of systems in a product line Among the existing approaches to variability modeling feature modeling and decision modeling have gained most importance A significant amount of research exists on comparing and analyzing different feature modeling approaches However, despite their significant role in product line research and practical applications, only little effort has been devoted to compare and analyze decision modeling approaches In order to address this shortcoming and to provide a basis for more structured research on decision modeling in the future, we present a comparative analysis of representative approaches We identify their major modeling concepts and present an analysis of their commonalities and variabilities

Blocked clause elimination for QBF

Abstract: Quantified Boolean formulas (QBF) provide a powerful framework for encoding problems from various application domains, not least because efficient QBF solvers are available. Despite sophisticated evaluation techniques, the performance of such a solver usually depends on the way a problem is represented. However, the translation to processable QBF encodings is in general not unique and may either introduce variables and clauses not relevant for the solving process or blur information which could be beneficial for the solving process. To deal with both of these issues, preprocessors have been introduced which rewrite a given QBF before it is passed to a solver. In this paper, we present novel preprocessing methods for QBF based on blocked clause elimination (BCE), a technique successfully applied in SAT. Quantified blocked clause elimination (QBCE) allows to simulate various structural preprocessing techniques as BCE in SAT. We have implemented QBCE and extensions of QBCE in the preprocessor bloqqer. In our experiments we show that preprocessing with QBCE reduces formulas substantially and allows us to solve considerable more instances than the previous state-of-the-art.

The concrete tetrahedron

Abstract: We give an overview over computer algebra algorithms for dealing with symbolic sums, recurrence equations, generating functions, and asymptotic estimates, and we will illustrate how to apply these algorithms to problems arising in discrete mathematics.

The 2010 Eurobarometer on the life sciences

Abstract: Since 1991, the triennial Eurobarometer survey has assessed public attitudes about biotech and the life sciences in Europe. The latest 2010 Eurobarometer survey on the Life Sciences and Biotechnology (http://ec.europa.eu/research/science-society/document_library/pdf_06/europeans-biotechnology-in-2010_en.pdf), based on representative samples from 32 European countries, hints at a new era in the relations between science and society. We see less criticism of technology based on distrust in government and industry; more enthusiasm for novel technologies; and a more sophisticated appraisal of what technologies offer in terms of benefits, safety and sustainability. Europeans want regulation in the public interest and want a voice in such regulation when social values are at stake; we highlight an emerging European landscape of social value differences that shape people's views of technologies.