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In this talk, I would like to share my experiences gained from participating in four CSP solver competitions and the second ASP solver competition. In particular, I’ll talk about how various programming techniques can make huge differences in solving some of the benchmark problems used in the competitions. These techniques include global constraints, table constraints, and problem-specific propagators and labeling strategies for selecting variables and values. I’ll present these techniques with experimental results from B-Prolog and other CLP(FD) systems.
Integration of digital elevation models and satellite images to investigate geological processes.
(2006)
In order to better understand the geological boundary conditions for ongoing or past surface processes geologists face two important questions: 1) How can we gain additional knowledge about geological processes by analyzing digital elevation models (DEM) and satellite images and 2) Do these efforts present a viable approach for more efficient research. Here, we will present case studies at a variety of scales and levels of resolution to illustrate how we can substantially complement and enhance classical geological approaches with remote sensing techniques. Commonly, satellite and DEM based studies are being used in a first step of assessing areas of geologic interest. While in the past the analysis of satellite imagery (e.g. Landsat TM) and aerial photographs was carried out to characterize the regional geologic characteristics, particularly structure and lithology, geologists have increasingly ventured into a process-oriented approach. This entails assessing structures and geomorphic features with a concept that includes active tectonics or tectonic activity on time scales relevant to humans. In addition, these efforts involve analyzing and quantifying the processes acting at the surface by integrating different remote sensing and topographic data (e.g. SRTM-DEM, SSM/I, GPS, Landsat 7 ETM, Aster, Ikonos…). A combined structural and geomorphic study in the hyperarid Atacama desert demonstrates the use of satellite and digital elevation data for assessing geological structures formed by long-term (millions of years) feedback mechanisms between erosion and crustal bending (Zeilinger et al., 2005). The medium-term change of landscapes during hundred thousands to millions years in a more humid setting is shown in an example from southern Chile. Based on an analysis of rivers/watersheds combined with landscapes parameterization by using digital elevation models, the geomorphic evolution and change in drainage pattern in the coastal Cordillera can be quantified and put into the context of seismotectonic segmentation of a tectonically active region. This has far-reaching implications for earthquake rupture scenarios and hazard mitigation (K. Rehak, see poster on IMAF Workshop). Two examples illustrate short-term processes on decadal, centennial and millennial time scales: One study uses orogen scale precipitation gradients derived from remotely sensed passive microwave data (Bookhagen et al., 2005a). They demonstrate how debris flows were triggered as a response of slopes to abnormally strong rainfall in the interior parts of the Himalaya during intensified monsoons. The area of the orogen that receives high amounts of precipitation during intensified monsoons also constitutes numerous landslide deposits of up to 1km<sup>3 volume that were generated during intensified monsoon phase at about 27 and 9 ka (Bookhagen et al., 2005b). Another project in the Swiss Alps compared sets of aerial photographs recorded in different years. By calculating high resolution surfaces the mass transport in a landslide could be reconstructed (M. Schwab, Universität Bern). All these examples, although representing only a short and limited selection of projects using remote sense data in geology, have as a common approach the goal to quantify geological processes. With increasing data resolution and new sensors future projects will even enable us to recognize more patterns and / or structures indicative of geological processes in tectonically active areas. This is crucial for the analysis of natural hazards like earthquakes, tsunamis and landslides, as well as those hazards that are related to climatic variability. The integration of remotely sensed data at different spatial and temporal scales with field observations becomes increasingly important. Many of presently highly populated places and increasingly utilized regions are subject to significant environmental pressure and often constitute areas of concentrated economic value. Combined remote sensing and ground-truthing in these regions is particularly important as geologic, seismicity and hydrologic data may be limited here due to the recency of infrastructural development. Monitoring ongoing processes and evaluating the remotely sensed data in terms of recurrence of events will greatly enhance our ability to assess and mitigate natural hazards. <hr> Dokument 1: Foliensatz | Dokument 2: Abstract <hr> Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
In this paper, we present a finite-state approach to constituency and therewith an analysis of coordination phenomena involving so-called non-constituents. We show that non-constituents can be seen as parts of fully-fledged constituents and therefore be coordinated in the same way. We have implemented an algorithm based on finite state automata that generates an LFG grammar assigning valid analyses to non-constituent coordination structures in the German language.
Nested complementation plays an important role in expressing counter- i.e. star-free and first-order definable languages and their hierarchies. In addition, methods that compile phonological rules into finite-state networks use double-nested complementation or “double negation”. This paper reviews how the double-nested complementation extends to a relatively new operation, generalized restriction (GR), coined by the author (Yli-Jyrä and Koskenniemi 2004). This operation encapsulates a double-nested complementation and elimination of a concatenation marker, diamond, whose finite occurrences align concatenations in the arguments of the operation. The paper demonstrates that the GR operation has an interesting potential in expressing regular languages, various kinds of grammars, bimorphisms and relations. This motivates a further study of optimized implementation of the operator.
Generalized Two-Level Grammar (GTWOL) provides a new method for compilation of parallel replacement rules into transducers. The current paper identifies the role of generalized lenient composition (GLC) in this method. Thanks to the GLC operation, the compilation method becomes bipartite and easily extendible to capture various application modes. In the light of three notions of obligatoriness, a modification to the compilation method is proposed. We argue that the bipartite design makes implementation of parallel obligatoriness, directionality, length and rank based application modes extremely easy, which is the main result of the paper.
We analyze anaphoric phenomena in the context of building an input understanding component for a conversational system for tutoring mathematics. In this paper, we report the results of data analysis of two sets of corpora of dialogs on mathematical theorem proving. We exemplify anaphoric phenomena, identify factors relevant to anaphora resolution in our domain and extensions to the input interpretation component to support it.
The most massive stars are those with the shortest but most active life. One group of massive stars, the Luminous Blue Variables (LBVs), of which only a few objects are known, are in particular of interest concerning the stability of stars. They have a high mass loss rate and are close to being instable. This is even more likely as rotation becomes an important factor in stellar evolution of these stars. Through massive stellar winds and sometimes giant eruptions, LBV nebulae are formed. Various aspects in the evolution in the LBV phase lead, beside the large scale morphological and kinematical differences, to a diversity of small structures like clumps, rims, and outflows in these nebulae.
Die Präsentation gibt zuerst einen Überblick über mögliche Parameter für die Wasserhaushaltsmodellierung, die aus Fernerkundungs(FE)-daten generell abgeleitet werden können. Bei der Beschreibung der Ableitungsverfahren dieser Parameter aus (FE)-Daten wird auf die Landnutzung, Vegetationsindices und die reale Evapotranspiration (ETr) fokussiert. Die Verfahren zur Bestimmung der ETr aus optischen FE-Daten lassen grob wie folgt gliedern : • Direkte Ableitung der Evapotranspiration aus radiometrisch bestimmten Oberflächen-temperaturen • Ableitung von Modellinputdaten wie z.B. Globalstrahlung, Albedo, Blattflächeniondex LAI und NDVI aus FE-Daten zur Anwendung von SoilVegetation-AtmosphereTransfer- und Energiebilanzmodellen wie z.B. SEBAL (Bastiaansen et al . 1998) • Kombinierte Anwendung verschiedenster Sensoren wie SAR-ERS1, LANDSAT-TM, NOAA-AHVRR mit SVAT-Modellen und hydrologischen Einzugsgebietsmodellen Die Validierung dieser Methoden wurde in verschiedenen Messkampagnen wie z.B. Lo-trex10E-HIBE, FIFE oder HAPEX-Sahel durchgeführt. Dabei wurde die aus dem entspre-chenden Sensor abgeleitete ETr mit gemessenen ETr-Raten von Ankerstationen innerhalb eines definierten Gebietes verglichen. Diese Ankerstationen leiteten die ETr aus Profil-, Ed-dy-Flux-, oder Szintillometermessungen ab. Durchgängige längere Zeitreihen der ETr sind nur mit FE-Daten mit hoher Wiederholungsrate wie z.B. NOAA-AVHRR, MODIS hoher Zeitauflösung möglich Mit Landsat-TM z.B. ergeben sich dagegen nur „Snap Shots“ der ETr von einzelnen Tagen. Daher wurden oftmals Multisensorverfahren d.h. Kombination von z.B. Landsat-TM mit NOAA-AVHRR eingesetzt oder die FE-Daten nur für die Erhebung zeitin-varianter Eingangsdaten (z.B. Landnutzung) und zur raumbezogenen Validierung der ETr-Berechnungen von hydrologischen Modellen verwendet. Im zweiten Teil des Vortrags wird ein Anwendungsbeispiel für den Versuch einer räumliche Validierung eines Wasserhaus-haltsmodells über NDVI-ETr-Datenprodukte aus Landsat-TM5-Daten für das Stobbergebiet. Ein weiteres Anwendungsbeispiel für die Einbindung von Landnutzungsdatenprodukten aus Landsat-TM5-Daten in die Wasserhaushaltmodellierung für das Ucker-Einzugsgebiet schliesst den Vortrag ab. <hr> Dokument 1: Foliensatz | Dokument 2: Abstract <hr> Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006