782 research outputs found
Structure oriented case based reasoning
Das Ziel dieser Arbeit war es, durch Verwendung geeigneter vorhandener CAD-Pläne die Bearbeitung neuer CAD-Pläne zu unterstützen. Entstanden ist ein generischer Ansatz zum fallbasierten Schließens. Da in CAD-Plänen die räumliche Struktur eine wichtige Rolle spielt, ist das Konzept auf strukturorientierte Anwendungen ausgerichtet. Deshalb bezeichne ich es als ein Konzept zum " strukturorientierten fallbasierten Schließen". Die Arbeit spezifiziert das Minimum an Wissen, welches zur Suche und Wiederverwendung von Fällen benötigt wird, wie das darüber hinausgehende Wissen verarbeitet wird, welche Zusammenhänge es zum Beispiel zwischen Vergleichs- und Anpassungswissen gibt und wie man das Wissen modellieren kann. Zur Erläuterung wird das benötigte Wissen anhand verschiedener Anwendungen dargestellt. Das in der Arbeit vorgestellte Konzept erlaubt die Ergänzung, Detaillierung und Korrektur einer Anfrage. Die beiden entscheidenden Algorithmen dienen dem Vergleich von Anfrage und Fall und der Anpassung der Information des Falles zur Modifikation der Anfrage.The task of this thesis was the computer supported reuse of known CAD-designs in order to create new CAD-designs. The developed solution contains a generic approach to case based reasoning. Due to the relevance of spatial structures in CAD-designs the approach focusses on structure oriented applications. Therefore it is called an approach for „structure oriented case based reasoning". This thesis specifies the kind of the minimum knowledge required for retrieval and reuse of cases, how to integrate additional knowledge, relations between knowledge needed for comparision and adaption and how to model the knowledge. For illustration the required knowledge is described for different applications. The developed concept allows to extend, detail and correct a given query. The two most important algorithms are used to compare cases and query and to reuse the information found in a case to modify a query
The seismic conversion log and its application to vertical seismic profiling at the German Continental Deep Drilling Site (KTB)
The conversion of compressional to shear waves in a vertical seismic profile (VSP), recorded in 1999 between 3-8.5 km depth at the German Continental Deep Drilling Site (KTB) was quantified with the newly developed conversion log method and analyzed in detail. The experiment yielded high quality seismic data in terms of signal bandwidth, signal-to-noise ratio, amplitude reference, and stability of the source signal. Important facts were obtained: The source signal proved to be simple. Its multi-phase signature is a result of multi-pathing within the crust. The determination of attenuation values in a complicated crustal environment is hampered by the structural features. In a scattering environment the wave conversion log method is not only capable of determining the conversion amplitude from the direct vicinity of the borehole but also from distant conversion points. The conversion in the field data as well as in model data is frequency dependent in an unusual manner; intermediate frequency signals (30-60 Hz) convert less than low (15-30 Hz) and high frequency signals (60-240 Hz). In the crust at the KTB site only about 10% - 50% of the conversion originates from the variation of the mineral composition of the rocks. Wave conversion depends on the fracture density. However, wave conversion is also highly dependent on chlorite content that seems to 'heal' the influence of cracks and fissures. This is important for crustal surface seismic experiments aiming at the reflection analysis of fault zones
Use of Bovine Milk Concentrate Containing Antibody to Rotavirus to Treat Rotavirus Gastroenteritis in Infants
The use of a concentrate containing milk immunoglobulins prepared from rotavirus-hyperimmunized cows (neutralization titer, 1:6,000 for a 10% solution) to treat infants hospitalized for acute rotavirus gastroenteritis resulted in a significant (P = .008) reduction in the duration of excretion of virus. Stool samples from treated infants showed the presence of bovine milk immunoglobulins in 47% of cases and of neutralizing activity in 43% (mean neutralization titer, 1:48); stool samples from control infants showed neutralizing activities in only 3% of cases (neutralization titers, <1:20). Immunoelectrophoresis of stool extracts revealed fragment A, a bovine analogue of F(ab′)2 or Fab, as the major product of in vitro and in vivo digestion of the immunoglobulins. Cessation of excretion of virus correlated with the appearance of neutralizing activities in 19 of 25 infants. Only concentrate-treated infants with high neutralizing activity in stools showed a statistically significant reduction in duration of excretion of virus; this duration in concentrate-treated infants with low neutralizing activity was comparable with control
Exkursionspunkt 2: Besucherbergwerk BĂĽchenberg
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KI-Methoden beim Entwurf komplexer Gebäude
Anhand von Ergebnissen aus dem FABEL-Projekt wird gezeigt, welche Beiträge Methoden der Künstlichen Intelligenz, insbesondere der Wissensverarbeitung beim Entwurf komplexer Gebäude leisten können. Exemplarisch werden spezialisierte wissensintensive Methoden, und allgemeine fallbasierte Methoden zum Retrieval und zur Wiederverwendung früherer Entwürfe vorgestellt. Es werden Fragen der Integration von Wissen, Fällen und Daten diskutiert. Der Prototyp des FABEL-Projekts verwendet die Metapher der virtuellen Baustelle, um die verschiedenen Methoden als Planungswerkzeuge in einem CAD-System integriert anzubieten. Ein Planungsmodell dient der zusätzlichen Orientierung des Planers. Die Ergebnisse sind interessant für den Entwurf komplexer Unikate, dürften aber auch als Zusatz zu elektronisch angebotenen Katalogen relevant sein
New socio-political environments and the dynamics of European public research systems
The performance of science and technology is being challenged by new socio-political
environments. The changes in science policy are influenced by a more systemic view of
the understanding on how science and technology evolve. The concept of risk society is mediating the links between science and society. Comparative analyses cast doubts about the possibilities of European institutions to cope with the challenges of the new environment.This paper is based on the work and previous experience of the author and develops some results from the project 'European Comparison of Public Research Systems (EUPSR)', funded by the European Commission TSER programme (contract SOE1-CT96-1036), co-ordinated by J. Senker (SPRU). The author is solely responsible for the work presented in this paper. The support of the EC is gratefully acknowledged as well as that of the Spanish National R&D Plan (SEC97-1382). A preliminary version was presented in the Lisbon Workshop (5-6 June 2000) of the EUROPOLIS project funded by the STRATA Programme
The trough-system algorithm and its application to spatial modeling of Greenland subglacial topography
This is the published version. Copyright 2014 Herzfeld et al.Dynamic ice-sheet models are used to assess the contribution of mass loss from the Greenland ice sheet to sea-level rise. Mass transfer from ice sheet to ocean is in a large part through outlet glaciers. Bed topography plays an important role in ice dynamics, since the acceleration from the slow-moving inland ice to an ice stream is in many cases caused by the existence of a subglacial trough or trough system. Problems are that most subglacial troughs are features of a scale not resolved in most ice-sheet models and that radar measurements of subglacial topography do not always reach the bottoms of narrow troughs. The trough-system algorithm introduced here employs mathematical morphology and algebraic topology to correctly represent subscale features in a topographic generalization, so the effects of troughs on ice flow are retained in ice-dynamic models. The algorithm is applied to derive a spatial elevation model of Greenland subglacial topography, integrating recently collected radar measurements (CReSIS data) of the Jakobshavn Isbræ, Helheim, Kangerdlussuaq and Petermann glacier regions. The resultant JakHelKanPet digital elevation model has been applied in dynamic ice-sheet modeling and sea-level-rise assessment
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Trapping, chemistry, and export of trace gases in the South Asian summer monsoon observed during CARIBIC flights in 2008
The CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) passenger aircraft observatory performed in situ measurements at 10–12 km altitude in the South Asian summer monsoon anticyclone between June and September 2008. These measurements enable us to investigate this atmospheric region (which so far has mostly been observed from satellites) using the broad suite of trace gases and aerosol particles measured by CARIBIC. Elevated levels of a variety of atmospheric pollutants (e.g. carbon monoxide, total reactive nitrogen oxides, aerosol particles, and several volatile organic compounds) were recorded. The measurements provide detailed information about the chemical composition of air in different parts of the monsoon anticyclone, particularly of ozone precursors. While covering a range of 3500 km inside the monsoon anticyclone, CARIBIC observations show remarkable consistency, i.e. with distinct latitudinal patterns of trace gases during the entire monsoon period.
Using the CARIBIC trace gas and aerosol particle measurements in combination with the Lagrangian particle dispersion model FLEXPART, we investigated the characteristics of monsoon outflow and the chemical evolution of air masses during transport. The trajectory calculations indicate that these air masses originated mainly from South Asia and mainland Southeast Asia. Estimated photochemical ages of the air were found to agree well with transport times from a source region east of 90–95° E. The photochemical ages of the air in the southern part of the monsoon anticyclone were systematically younger (less than 7 days) and the air masses were mostly in an ozone-forming chemical mode. In its northern part the air masses were older (up to 13 days) and had unclear ozone formation or destruction potential. Based on analysis of forward trajectories, several receptor regions were identified. In addition to predominantly westward transport, we found evidence for efficient transport (within 10 days) to the Pacific and North America, particularly during June and September, and also of cross-tropopause exchange, which was strongest during June and July. Westward transport to Africa and further to the Mediterranean was the main pathway during July
Association of Hepatitis C Virus—Specific CD8+ T Cells with Viral Clearance in Acute Hepatitis C
CD8+ T lymphocytes play a major role in antiviral immune defense. Their significance for acute hepatitis C is unclear. Our aim was to correlate the CD8+ T cell response with the outcome of infection. Eighteen patients with acute hepatitis C and 19 normal donors were studied. Hepatitis C virus (HCV)—specific CD8+ T cells were identified in the enzyme-linked immunospot assay by their interferon-γ (IFN-γ) production after specific stimulation. The highest numbers of IFN-γ—producing HCV-specific CD8+ T cells were found in patients with acute hepatitis C and a self-limited course of disease during the first 6 months after onset of disease, but these numbers dropped thereafter to undetectable levels. The differences in responsiveness between patients with self-limited disease versus patients with a chronic course were statistically significant (P < .001). Our data show that the number of IFN—γ-producing HCV-specific CD8+ T cells during the first 6 months after onset of disease is associated with eradication of the HCV infectio
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