Fostering sharing of unshared knowledge by having access to the collaborators’ meta-knowledge structures

The present experimental study focuses on two problems occurring in computer-supported collaborative learning situations: First, it has been empirically proven that groups discuss mainly shared information, that is, information already known to all group members, while unshared information, that is, information known to only one member, is often neglected. However, such unshared information could be task-relevant. Therefore, taking unshared information into consideration should be fostered. Second, Wegner’s theory of transactive memory system points out that groups perform better when the group members are informed about their collaborators’ knowledge. However, acquiring correct knowledge about what others know is difficult. An approach for solving these two problems is introduced which provides the group members with the collaborators’ meta-knowledge structures by means of digital concept maps. The study compares 20 triads with spatially distributed group members that had access to their collaborators’ meta-knowledge maps with 20 triads collaborating without these maps. Results showed, as expected, that the triads having been provided with such maps started sooner to discuss unshared information, applied more of their collaborators’ unshared information, and processed unshared information more deeply. Additional results, however, demonstrated in contrast to Wegner’s theory that being informed about the collaborators’ meta-knowledge is not sufficient to increase group performance.     

On the Complexity of 2-Monotone Restarting Automata

The -automaton is the weakest form of the nondeterministic version of the restarting automaton that was introduced by Jančar et al. to model the so-called analysis by reduction. Here it is shown that the class ℒ(R) of languages that are accepted by -automata is incomparable under set inclusion to the class of Church-Rosser languages and to the class of growing context-sensitive languages. In fact this already holds for the class of languages that are accepted by 2-monotone -automata. In addition, we prove that already the latter class contains -complete languages, showing that already the 2-monotone -automaton has a surprisingly large expressive power. The results of this paper have been announced at DLT 2004 in Auckland, New Zealand. This work was mainly carried out while T. Jurdziński was visiting the University of Kassel, supported by a grant from the Deutsche Forschungsgemeinschaft (DFG). F. Mráz and M. Plátek were partially supported by the Grant Agency of the Czech Republic under Grant-No. 201/04/2102 and by the program ‘Information Society’ under project 1ET100300517. F. Mráz was also supported by the Grant Agency of Charles University in Prague under Grant-No. 358/2006/A-INF/MFF.     

Multiresponse imaging: Information and fidelity

Multiresponse imaging is a process that acquires images, each with a different optical response, and reassembles them into a single image with an improved resolution that can approach times the photodetector-array sampling lattice. Our goals are to optimize the performance of this process in terms of the resolution and fidelity of the restored image and to assess the amount of information required to do so. The theoretical approach is based on the extension of both image restoration and rate distortion theories from their traditional realm of signal processing to image processing which includes image gathering and display.     

The influence of brittle boundary layers on the strength of fibrous metallic composites

The brittle boundary layers often caused during the production of composites or by their treatment at higher temperatures, may change the mechanical properties. On the steel wire/aluminium system the growth of the intermetallic boundary phase and its influence on the strength of the composite were investigated. Hence followed a maximum strength at small layer thicknesses. By means of fracture investigations new models were developed which allow the calculation of the dependence of strength behaviour on layer thickness.List of symbols E _f Young's modulus of fibre - E _b Young's modulus of boundary layer - _c external load - _f tensile stress in the fibre - _m tensile stress in the matrix - _b tensile stress in the boundary layer - _uc,f,b ultimate strength of the composite, the fibre or the boundary layer, respectively - averaged stress in the fibre - _bf shear stress in the boundary layer-fibre interface - ₀ shear strength of the boundary layer-fibre-interface - _uf ultimate strain of the fibre - fraction of the layer which has grown into the matrix - Weibull parameter - ^–1 characteristic length of stress transfer between fibre and boundary layer - d diameter of the boundary layer - 2l length of the boundary layer segments - r _f fibre radius - u(x) displacement field - v _{f, b,m} volume fraction of fibres, boundary layer or matrix respectively.     

Photometrische Mikrobestimmung der Reste keimt?tender QAV in Milch

Zusammenfassung Die photometrische Mikrobestimmung für Rückstände quaterndrer Ammoniumverbindungen (QAV) in Milch wurde weiterentwickelt: Insbesondere wurde als hauptsächliche Stäquelle das Milchprotein Casein ermittelt und weitgehend ausgeschaltet, die Bindung von QAV an Casein diskutiert, die untere Grenze der Bestimmbarkeit kationischer Tenside in Milch auf 0,2 mg/l gesenkt und das Analysenverfahren für einige Milchprodukte (Rahm, Joghurt und Quark) modifiziert, so daß 1 mg/kg noch bestimmt werden kann.

---

Photometric micro-determination of the residues of disinfectant quaternary ammonium compounds in milk3. Improvement and adaption for milk products

Summary The photometric method for the quantitative micro-determination of the residues of quaternary ammonium compounds (QAC) in milk was improved. The casein has proved as an essential interfering substance and it was largely eliminated. Furthermore the bond of QAC on casein in discussed. The minimum level für determination for QAC in milk was reduced to 0.2 ppm. By modifying the photometric method for some milk-products as cream, joghurt, and quarg QAC can be determined at minimal concentrations of 1 ppm.

---

---

Teilauszug aus Friedrich Einreiner Entwicklung einer Analysenmethode für Rückstände kationischer Bactericide in Milch und Milchprodukten Dissertation Technische Universität München-Weihenstephan 1976     

Untersuchung und Zusammensetzung einiger Leguminosen

Zusammenfassung Im Anschluß an die qualitative und quantitative Bestandsaufnahme flüchtiger Inhaltsstoffe in Tomaten sind die Aromastoffzusammensetzungen technologisch unterschiedlich behandelter Tomatensäfte untersucht worden. 80 Aromakomponenten wurden gaschromatographisch-massenspektrometrisch identifiziert. Quantitative Vergleiche zeigten, daß bei der Saftherstellung enzymatisch einerseits aus ungesättigten Fettsduren eine Reihe von C₆-Komponenten, insbesondere 1-Hexanol andcis-3-Hexen-1-ol entstehen, andererseits einige Aromastoffe, die sich aus Carotinoidstrukturen ableiten lassen, wie 6-Methyl-5-hepten-2-on, Geranyl- und Farnesylaceton sowie-Ionen gebildet worden. Als Folgeprodukte thermischer Behandlungen sind u. a. erhöhte Gehalte an Acetoin, furfural, 5-Methylfurfural and 6-Methyl-5-hepten-2-on nachgewiesen worden. Die Verteilung der im Serum gelösten und der an Trubbestandteile gebundenen Aromastoffe wurde in den verschiedenen Säften quantitativ gaschromatographisch ermittelt.

---

The quantitative composition of natural and technologically changed aromas of plantsIV. Enzymic and thermal reaction products formed during the processing of tomatoes

Summary After the qualitative and quantitative investigation of the flavor compounds of tomatoes, the flavor compositions of tomato juices treated by different technological methods were determined. 80 aroma components were identified by gas chromatography and mass spectrometry. The quantitative comparisons showed that during the processing of juices unsaturated fatty acids acted as precursors for a series of C₆-compounds, especially 1-hexanol, and cis-3-hexen-l-ol and that on the other hand some aroma compounds derived from carotenoid like structures, e.g. 6-methyl-5-hepten-2-one, geranyl- and farnesylacetone and -ionone were formed. As reaction products of thermal treatments among others increased amounts of acetoin, furfural, 5-methylfurfural and 6-methyl-5-hepten-2-one were established. The distribution of the aroma compounds dissolved in the serum or bound on the pulp was determined quantitatively by employing gaschromatographical methods.

---

---

III. Mitt.: P. Schreier, F. Drawert and A. Junker, Lebensm. Wiss. u. Technol. (im Druck). Die Arbeit wurde mit finanzieller Unterstützung des Forschungskreises der Ernährungsindustrie durchgeführt     

Sample size and correlational inference.

In 4 studies, the authors examined the hypothesis that the structure of the informational environment makes small samples more informative than large ones for drawing inferences about population correlations. The specific purpose of the studies was to test predictions arising from the signal detection simulations of R. B. Anderson, M. E. Doherty, N. D. Berg, and J. C. Friedrich (2005). The results of a simulation study in the present article confirmed and extended previous theoretical claims (R. B. Anderson et al., 2005) that in a yes/no correlation detection task, small-sample advantages should occur but should be restricted to particular decision conditions. In 3 behavioral studies, participants viewed larger or smaller samples of data pairs and judged whether each sample had been drawn from a population characterized by a zero correlation or from one characterized by a greater-than-zero correlation. Consistent with traditional statistical theory, accuracy tended to be greater for larger than for smaller samples, though there was a small-sample advantage in 1 experimental condition. The results are discussed in relation to alternative theoretical and behavioral paradigms such as those of Y. Kareev (e.g., 2005) and K. Fiedler and Y. Kareev (2006). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Numerical study on the prediction of microstructure parameters by multi-scale modeling of directional solidification of binary aluminum–silicon alloys

In order to create a model to predict microstructural quantities like grain size, primary and secondary dendrite arm spacing a multi-phase and multi-scale model based on the work of Wang and Beckermann [C. Wang, C. Beckermann, Metallurgical and Materials Transactions A 27A (1996) 2754–2764] was combined with a front tracking technique [A. Wu, A. Ludwig, in: C.-A. Gandin, M. Bellet (Eds.), Modeling of Casting, Welding, and Advanced Solidification Processes – XI, TMS, 2006, pp. 291–298], micro-models for nucleation [M. Rappaz, P. Thevoz, Acta Metallurgica 35 (7) (1987) 1487–1497], primary [J. Hunt, S.-Z. Lu, Metallurgical and Materials Transactions A 27A (1996) 611–623], secondary [W. Kurz, D. Fisher, Fundamentals of Solidification, Trans Tech Publication, 1986, ISBN 0-87849-522-3] dendrite arm spacing and a control volume based finite element solver for axial-symmetric problems. As most of the micro-models are just valid for pure diffusive conditions, the model just takes into account macroscopic diffusion in the melt and thus neglects the influence of melt flow. The new software was used for a comprehensive comparison to several test cases. The validation includes investigation of the correlation of calculated and measured grain size distributions for inoculated alloys. Experimental and numerical data for the primary and secondary dendrite arm spacing for steady state and transient directional solidification were compared in a second step. A good correlation is found for all test cases.     

A resolution study for electrostatic force microscopy on bimetallic samples using the boundary element method

Electrostatic force microscopy (EFM) is a special design of non-contact atomic force microscopy used for detecting electrostatic interactions between the probe tip and the sample. Its resolution is limited by the finite probe size and the long-range characteristics of electrostatic forces. Therefore, quantitative analysis is crucial to understanding the relationship between the actual local surface potential distribution and the quantities obtained from EFM measurements. To study EFM measurements on bimetallic samples with surface potential inhomogeneities as a special case, we have simulated such measurements using the boundary element method and calculated the force component and force gradient component that would be measured by amplitude modulation (AM) EFM and frequency modulation (FM) EFM, respectively. Such analyses have been performed for inhomogeneities of various shapes and sizes, for different tip-sample separations and tip geometries, for different applied voltages, and for different media (e.g., vacuum or water) in which the experiment is performed. For a sample with a surface potential discontinuity, the FM-EFM resolution expression agrees with the literature; however, the simulation for AM-EFM suggests the existence of an optimal tip radius of curvature in terms of resolution. On the other hand, for samples with strip-?and disk-shaped surface potential inhomogeneities, we have obtained quantitative expressions for the detectability size requirements as a function of experimental conditions for both AM-?and FM-EFMs, which suggest that a larger tip radius of curvature is moderately favored for detecting the presence of such inhomogeneities.