Verified stochastic methods

Markov chains provide quite attractive features for simulating a system’s behavior under consideration of uncertainties. However, their use is somewhat limited because of their deterministic transition matrices. Vague probabilistic information and imprecision appear in the modeling of real-life systems, thus causing difficulties in the pure probabilistic model set-up. Moreover, their accuracy suffers due to implementations on computers with floating point arithmetics. Our goal is to address these problems by extending the Dempster-Shafer with Intervals toolbox for MATLAB with novel verified algorithms for modeling that work with Markov chains with imprecise transition matrices, known as Markov set-chains. Additionally, in order to provide a statistical estimation tool that can handle imprecision to set up Markov chain models, we develop a new verified algorithm for computing relations between the mean and the standard deviation of fuzzy sets.     

Comparative in Vivo Assessment of Some Adverse Bioeffects of Equidimensional Gold and Silver Nanoparticles and the Attenuation of Nanosilver’s Effects with a Complex of Innocuous Bioprotectors

Stable suspensions of nanogold (NG) and nanosilver (NS) with mean particle diameter 50 and 49 nm, respectively, were prepared by laser ablation of metals in water. To assess rat’s pulmonary phagocytosis response to a single intratracheal instillation of these suspensions, we used optical, transmission electron, and semi-contact atomic force microscopy. NG and NS were also repeatedly injected intraperitoneally into rats at a dose of 10 mg/kg (0.5 mg per mL of deionized water) three times a week, up to 20 injections. A group of rats was thus injected with NS after oral administration of a “bioprotective complex” (BPC) comprised of pectin, multivitamins, some amino acids, calcium, selenium, and omega-3 PUFA. After the termination of the injections, many functional and biochemical indices and histopathological features of the spleen, kidneys and liver were evaluated for signs of toxicity, and accumulation of NG or NS in these organs was measured. From the same rats, we obtained cell suspensions of different tissues for performing the RAPD test. It was demonstrated that, although both nanometals were adversely bioactive in all respects considered in this study, NS was more noxious as compared with NG, and that the BPC tested by us attenuated both the toxicity and genotoxicity of NS.     

More confident,less formal: stylistic changes in academic psychology writing from 1970 to 2016

Scientometrics - Stylistic changes in academic psychology writing were examined in a corpus of 790,520 psychology journal article abstracts published between 1970 and 2016. We anticipated that...     

Formation of pores and amorphous-nanocrystalline phases in porous TiNi alloys made by self-propagating high-temperature synthesis (SHS)

The objective of this study was to examine the mechanism how the surface of porous TiNi compounds produced by SHS method evolves. The prepared samples were investigated using light-microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive x-ray spectroscopy (EDS). The results indicated that the surface of all pores is represented by a granular stratum due to dendrite liquation by peritectic crystallization mechanism. The voids of 2–15?μm in size are formed owing to a capillary spreading of the liquid. Reaction gases with dissociated carbon, nitrogen, and oxygen are responsible for heat-and-mass transfer through the forming pores. High pressure-temperature effect of reaction gases on the melt causes the forming voids to coalesce, as well as transfers the peritectic liquid (PL) throughout the open pores catalyzing a distinctive spitted topography. It is through the chemisorption of gasiform nonmetallics by the pore surface melt, where these impurities are chemically bound, that it was formed a massive corrosion-resistant amorphous-nanocrystalline stratified shell deduced as an intermetallic oxycarbonitride layer.     

Efficient sampling strategy and refinement strategy for randomized circle detection

Circle detection is fundamental in pattern recognition and computer vision. The randomized approach has received much attention for its computational benefit when compared with the Hough transform. In this paper, a multiple-evidence-based sampling strategy is proposed to speed up the randomized approach. Next, an efficient refinement strategy is proposed to improve the accuracy. Based on different kinds of ten test images, experimental results demonstrate the computation-saving and accuracy effects when plugging the proposed strategies into three existing circle detection methods.     

Thermal behavior of high-temperature fuel cells: reliable parameter identification and interval-based sliding mode control

In this contribution, we present interval methods for mathematical modeling, for parameter identification, and for control design of dynamical systems. The corresponding approaches are applied to the thermal subsystem of a high-temperature solid oxide fuel cell (SOFC) which is available as a test rig at the Chair of Mechatronics at the University of Rostock. In practice, most internal parameters of SOFC stack modules cannot be measured directly. Therefore, system characteristics such as heat capacities or internal thermal resistances cannot be identified exactly, but only bounded. For this reason, intervals represent a good first approach to dealing with parameter uncertainty. In the first part of the paper, we present interval methods for the parameter identification aiming at the computation of globally optimal parameterizations. In comparison with classical local optimization procedures, the approximation quality is improved by the presented identification approach. The corresponding bounds for admissible domains are used to design a robust sliding mode control law for arbitrary operating points compensating the impact of disturbances and parameter uncertainties in a reliable way. In the second part of the paper, we show a simple approach to handling non-smoothness appearing in SOFC models based on ordinary differential equations in a verified way. We use a generalized derivative definition for a certain type of non-smooth functions inside the algorithm of the verified solver ValEncIA-IVP to be able to compute solutions to non-smooth initial value problems. The applicability of our method is demonstrated using the designed sliding mode controller.     

Conceptual metaphor theory meets the data: a corpus-based human annotation study

Metaphor makes our thoughts more vivid and fills our communication with richer imagery. Furthermore, according to the conceptual metaphor theory (CMT) of Lakoff and Johnson (Metaphors we live by. University of Chicago Press, Chicago, 1980), metaphor also plays an important structural role in the organization and processing of conceptual knowledge. According to this account, the phenomenon of metaphor is not restricted to similarity-based extensions of meanings of individual words, but instead involves activating fixed mappings that reconceptualize one whole area of experience in terms of another. CMT produced a significant resonance in the fields of philosophy, linguistics, cognitive science and artificial intelligence and still underlies a large proportion of modern research on metaphor. However, there has to date been no comprehensive corpus-based study of conceptual metaphor, which would provide an empirical basis for evaluating the CMT using real-world linguistic data. The annotation scheme and the empirical study we present in this paper is a step towards filling this gap. We test our annotation procedure in an experimental setting involving multiple annotators and estimate their agreement on the task. The goal of the study is to investigate (1) how intuitive the conceptual metaphor explanation of linguistic metaphors is for human annotators and whether it is possible to consistently annotate interconceptual mappings; (2) what are the main difficulties that the annotators experience during the annotation process; (3) whether one conceptual metaphor is sufficient to explain a linguistic metaphor or whether a chain of conceptual metaphors is needed. The resulting corpus annotated for conceptual mappings provides a new, valuable dataset for linguistic, computational and cognitive experiments on metaphor.     

Understanding privacy policies

Their is growing recognition that users of web-based systems want to understand, if not control, what customer’s data is stored by whom, for what purpose, for what duration, and with whom it is shared. We inform current language-based privacy efforts with an empirical study of P3P—the W3C domain-specific language for privacy policies. We use methods of software language engineering to study usage profiles, correctness of policies, metrics, cloning, and language extensions. The study supports the conclusion that P3P’s approach to policy validation is too weak to ensure correct use of the language. The study also discovers common, dominating policies, which may suggest a simpler approach to web privacy. Further, the study investigates a range of metrics for policies in an attempt to discover particularly interesting or complex policies. Finally, the study also attempts to discover symptoms of the need for extending the P3P language, but the found results are not conclusive here.     

Analyzing place metaphors in 3D educational collaborative virtual environments

In the recent years, the usage of three dimensional (3D) collaborative virtual environments (CVEs) for educational purposes has increased. The metaphors behind the design of virtual places are quite diverse, from replication of real universities to art museums and scientific labs. This paper reports the results of a case study where the students of our university, as a part of their course assignment, analyzed place metaphors used in a range of 3D educational CVEs vs. the corresponding educational goals. The students suggested a design for a virtual campus representing the Norwegian University of Science and Technology (NTNU). The results of this study provide some suggestions concerning the characterization of different design features in educational CVEs and the suitability of such features for different educational goals. Also, a preliminary set of design guidelines for an ideal virtual campus representing a real university is presented. Finally, some challenges associated with using 3D CVEs in various educational situations are discussed.