@inproceedings{Fullerton2007, author = {Fullerton, A. W.}, title = {Discussion: Spectral modeling}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17917}, year = {2007}, language = {en} } @inproceedings{Townsend2007, author = {Townsend, R. H. D.}, title = {Techniques for simulating radiative transfer through porous media}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17866}, year = {2007}, abstract = {In this contribution, I discuss some basic techniques that can be used to simulate radiative transfer through porous media. As specific examples, I consider scattering transfer through a clumped slab, and X-ray emission line formation in a clumped wind.}, language = {en} } @inproceedings{udDoula2007, author = {ud-Doula, A.}, title = {Large-scale wind structure due to magnetic fields}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18010}, year = {2007}, abstract = {Magnetic fields influence the dynamics of hot-star winds and create large scale structure. Based on numerical magnetohydrodynamic (MHD) simulations, we model the wind of θ¹ Ori C, and then use the SEI method to compute synthetic line profiles for a range of viewing angles as function of rotational phase. The resulting dynamic spectrum for a moderately strong line shows a distinct modulation, but with a phase that seems at odds with available observations.}, language = {en} } @inproceedings{IpingSonnebornMassaetal.2007, author = {Iping, R.C. and Sonneborn, G. and Massa, D.L. and Gies, D. and Williams, Simon E.}, title = {Far-ultraviolet spectroscopy of O+O binaries in the Magellanic Clouds}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17896}, year = {2007}, abstract = {We report FUSE observations in 2005-2006 of three O-type, double-lined spectroscopic binaries in the Magellanic Clouds. The systems have very short periods (1.4-2.25 d), represent rare, young evolutionary stages of massive stars and binaries, and provide a unique glimpse at some of the most massive systems that form in dense clusters of massive stars. Improved orbit parameters, including revised masses, for LH54-425 are derived from new ctio spectroscopy. The systems are: LH54-425 in the LMC (O3V + O5V, P=2.25d, 62+37M⊙), J053441-693139 in the LMC (O2-3If+O6V, P=1.4 d, 41+27M⊙), and Hodge 53-47 in the SMC (O6V + O4-5IIIf, P=2.2 d, 24+14M⊙, where the O4 star appears to be less massive than the O6 star). Their short periods indicates that wind interaction and mass transfer are likely important factors in their evolution. The spectra provide quantitative and systematic studies of phase-dependent stellar wind properties, wind collision effects in O+O binaries at lower metallicities, improved radial velocity curves, and FUV spectro-photometric changes as a function of orbital phase.}, language = {en} } @inproceedings{KustererNagelWerneretal.2007, author = {Kusterer, D.-J. and Nagel, T. and Werner, K. and Feldmeier, Achim}, title = {Radiative transfer in CV disk winds}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17847}, year = {2007}, abstract = {Mass accretion onto compact objects through accretion disks is a common phenomenon in the universe. It is seen in all energy domains from active galactic nuclei through cataclysmic variables (CVs) to young stellar objects. Because CVs are fairly easy to observe, they provide an ideal opportunity to study accretion disks in great detail and thus help us to understand accretion also in other energy ranges. Mass accretion in these objects is often accompanied by mass outflow from the disks. This accretion disk wind, at least in CVs, is thought to be radiatively driven, similar to O star winds. WOMPAT, a 3-D Monte Carlo radiative transfer code for accretion disk winds of CVs is presented.}, language = {en} } @inproceedings{DaviesVinkOudmaijer2007, author = {Davies, B. and Vink, J. S. and Oudmaijer, R. D.}, title = {Modelling the polarimetric variability of hot stars}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17939}, year = {2007}, abstract = {Many hot stars exhibit stochastic polarimetric variability, thought to arise from clumping low in the wind. Here we investigate the wind properties required to reproduce this variability using analytic models, with particular emphasis on Luminous Blue Variables. We find that the winds must be highly structured, consisting of a large number of optically-thin clumps; while we find that the overall level of polarization should scale with mass-loss rate - consistent with observations of LBVs. The models also predict variability on very short timescales, which is supported by the results of a recent polarimetric monitoring campaign.}, language = {en} } @inproceedings{KubatSaad2007, author = {Kub{\´a}t, Jiř{\´i} and Saad, S. M.}, title = {Moving absorption bumps in the spectra of Be stars}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17879}, year = {2007}, abstract = {Several Be binaries exhibit an absorption bump moving across the blue wing of hydrogen emission lines towards the line center. This bump is demonstrated for the case of two bright Be stars, κ Dra and 4 Her. It is not clear what is the reason for this travelling bump.}, language = {en} } @inproceedings{Nielsen2007, author = {Nielsen, K. E.}, title = {On irregular line profiles in the optical spectrum of Eta Carinae}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18227}, year = {2007}, abstract = {The optical spectrum of Eta Carinae (η Car) is prominent in H I, He i and Fe ii wind lines, all of which vary both in absorption and emission with phase. The phase dependance is a consequence of the interaction between the two objects in the η Car binary (η Car A \& B). The binary system is enshrouded by ejecta from previous mass ejection events and consequently, η Car B is not directly observable. We have traced the He i lines over η Car's spectroscopic period, using HST/STIS data obtained with medium spectral, but high angular, resolving power, and created a radial velocity curve for the system. The He I lines are formed in the core of the system, and appear to be a composite of multiple features formed in spatially separated regions. The sources of their irregular line profiles are still not fully understood, but can be attributed to emission/absorption near the wind-wind interface and/or a direct consequence of the η Car A's, massive, clumpy wind. This paper will discuss the spectral variability, the narrow emission structure of the He i lines and how clumpiness of the winds may impede the construction of the reliable radial velocity curve, necessary for characterizations of especially η Car B.}, language = {en} } @inproceedings{CohenLeuteneggerTownsend2007, author = {Cohen, David H. and Leutenegger, M. A. and Townsend, R. H. D.}, title = {Quantitative analysis of resolved X-ray emission line profiles of O stars}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18115}, year = {2007}, abstract = {By quantitatively fitting simple emission line profile models that include both atomic opacity and porosity to the Chandra X-ray spectrum of ζ Pup, we are able to explore the trade-offs between reduced mass-loss rates and wind porosity. We find that reducing the mass-loss rate of ζ Pup by roughly a factor of four, to 1.5 × 10-6 M⊙ yr-1, enables simple non-porous wind models to provide good fits to the data. If, on the other hand, we take the literature mass-loss rate of 6×10-6 M⊙ yr-1, then to produce X-ray line profiles that fit the data, extreme porosity lengths - of h∞ ≈ 3 R∗ - are required. Moreover, these porous models do not provide better fits to the data than the non-porous, low optical depth models. Additionally, such huge porosity lengths do not seem realistic in light of 2-D numerical simulations of the wind instability.}, language = {en} } @inproceedings{MorrisonRotherKurschat2007, author = {Morrison, N. D. and Rother, R. and Kurschat, N.}, title = {Hα line profile variability in the B8Ia-type supergiant Rigel (β Ori)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18120}, year = {2007}, abstract = {Hα observations of Rigel obtained on 184 nights during the past ten years with the 1-m telescope and ´echelle spectrograph of Ritter Observatory are surveyed. The line profiles were classified in terms of morphology. About 1/4 of them are of P Cygni type, about 15\% inverse P Cygni, about 25\% double-peaked, about 1/3 pure absorption, and a few are single emission lines. Transformation of the profile from one type to another typically takes a few days. Although the line stays in absorption for extended intervals, only one high-velocity absorption event of the intensity reported by Kaufer et al. (1996a) was observed, in late 2006. Late in this event, Hα absorption occurred farther to the red than the red wing of a plausible photospheric absorption component, an indication of infalling material. In general, as the absorption events come to an end, the emission typically returns with an inverse P Cygni profile. The Hα profile class shows no obvious correlation with the radial velocity of C II λ6578, a photospheric absorption line.}, language = {en} } @inproceedings{CheneMoffatCrowther2007, author = {Chen{\´e}, A.-N. and Moffat, Anthony F. J. and Crowther, P. A.}, title = {Rapidly accelerating clumps in the winds of the very hot WNE Stars}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18163}, year = {2007}, abstract = {We study the time variability of emission lines in three WNE stars : WR 2 (WN2), WR 3 (WN3ha) and WR152 (WN3). While WR 2 shows no variability above the noise level, the other stars do show variation, which are like other WR stars in WR 152 but very fast in WR 3. From these motions, we deduce a value of β ∼1 for WR 3 that is like that seen in O stars and β ∼2-3 for WR 152, that is intermediate between other WR stars and WR 3.}, language = {en} } @inproceedings{Kholtygin2007, author = {Kholtygin, A. F.}, title = {Modelling the induced clumping stochastic line profile variability}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18180}, year = {2007}, abstract = {We model the line profile variability (lpv) in spectra of clumped stellar atmospheres using the Stochastic Clump Model (SCM) of the winds of early-type stars. In this model the formation of dense inhomogeneities (clumps) in the line driven winds is considered as being a stochastic process. It is supposed that the emission due to clumps mainly contributes to the intensities of emission lines in the stellar spectra. It is shown that in the framework of the SCM it is possible to reproduce both the mean line profiles and a common pattern of the lpv.}, language = {en} } @inproceedings{Cassinelli2007, author = {Cassinelli, Joseph P.}, title = {Discussion: Magnetic fields, variability}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18195}, year = {2007}, language = {en} } @inproceedings{StLouis2007, author = {St-Louis, N.}, title = {Discussion: Binaries, colliding winds, LBVs and high energy radiation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18155}, year = {2007}, abstract = {Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007}, language = {en} } @inproceedings{RomeroOwockiAraudoetal.2007, author = {Romero, G. E. and Owocki, S. P. and Araudo, A. T. and Townsend, R. H. D. and Benaglia, P.}, title = {Using gamma-rays to probe the clumped structure of stellar winds}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18210}, year = {2007}, abstract = {Gamma-rays can be produced by the interaction of a relativistic jet and the matter of the stellar wind in the subclass of massive X-ray binaries known as "microquasars". The relativistic jet is ejected from the surroundings of the compact object and interacts with cold protons from the stellar wind, producing pions that then quickly decay into gamma-rays. Since the resulting gamma-ray emissivity depends on the target density, the detection of rapid variability in microquasars with GLAST and the new generation of Cherenkov imaging arrays could be used to probe the clumped structure of the stellar wind. In particular, we show here that the relative fluctuation in gamma rays may scale with the square root of the ratio of porosity length to binary separation, \$\sqrt{h/a}\$, implying for example a ca. 10\% variation in gamma ray emission for a quite moderate porosity, h/a ∼ 0.01.}, language = {en} } @inproceedings{Weis2007, author = {Weis, K.}, title = {Wind relics : clumps, inhomogeneities and outflows in LBV nebulae}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18235}, year = {2007}, abstract = {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.}, language = {en} } @inproceedings{GeskeWolf2010, author = {Geske, Ulrich and Wolf, Armin}, title = {Preface}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41401}, year = {2010}, abstract = {The workshops on (constraint) logic programming (WLP) are the annual meeting of the Society of Logic Programming (GLP e.V.) and bring together researchers interested in logic programming, constraint programming, and related areas like databases, artificial intelligence and operations research. In this decade, previous workshops took place in Dresden (2008), W{\"u}rzburg (2007), Vienna (2006), Ulm (2005), Potsdam (2004), Dresden (2002), Kiel (2001), and W{\"u}rzburg (2000). Contributions to workshops deal with all theoretical, experimental, and application aspects of constraint programming (CP) and logic programming (LP), including foundations of constraint/ logic programming. Some of the special topics are constraint solving and optimization, extensions of functional logic programming, deductive databases, data mining, nonmonotonic reasoning, , interaction of CP/LP with other formalisms like agents, XML, JAVA, program analysis, program transformation, program verification, meta programming, parallelism and concurrency, answer set programming, implementation and software techniques (e.g., types, modularity, design patterns), applications (e.g., in production, environment, education, internet), constraint/logic programming for semantic web systems and applications, reasoning on the semantic web, data modelling for the web, semistructured data, and web query languages.}, language = {en} } @inproceedings{KrtičkaPulsKubat2007, author = {Krtička, Jiri and Puls, Joachim and Kub{\´a}t, Jiř{\´i}}, title = {The influence of clumping on predicted O star wind parameters}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17969}, year = {2007}, abstract = {We study the influence of clumping on the predicted wind structure of O-type stars. For this purpose we artificially include clumping into our stationary wind models. When the clumps are assumed to be optically thin, the radiative line force increases compared to corresponding unclumped models, with a similar effect on either the mass-loss rate or the terminal velocity (depending on the onset of clumping). Optically thick clumps, alternatively, might be able to decrease the radiative force.}, language = {en} } @inproceedings{KrausKubatKrtička2007, author = {Kraus, M. and Kub{\´a}t, Jiř{\´i} and Krtička, Jiri}, title = {Wind emission of OB supergiants and the influence of clumping}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17757}, year = {2007}, abstract = {The influence of the wind to the total continuum of OB supergiants is discussed. For wind velocity distributions with β > 1.0, the wind can have strong influence to the total continuum emission, even at optical wavelengths. Comparing the continuum emission of clumped and unclumped winds, especially for stars with high β values, delivers flux differences of up to 30\% with maximum in the near-IR. Continuum observations at these wavelengths are therefore an ideal tool to discriminate between clumped and unclumped winds of OB supergiants.}, language = {en} } @inproceedings{Cabalar2010, author = {Cabalar, Pedro}, title = {Existential quantifiers in the rule body}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41476}, year = {2010}, abstract = {In this paper we consider a simple syntactic extension of Answer Set Programming (ASP) for dealing with (nested) existential quantifiers and double negation in the rule bodies, in a close way to the recent proposal RASPL-1. The semantics for this extension just resorts to Equilibrium Logic (or, equivalently, to the General Theory of Stable Models), which provides a logic-programming interpretation for any arbitrary theory in the syntax of Predicate Calculus. We present a translation of this syntactic class into standard logic programs with variables (either disjunctive or normal, depending on the input rule heads), as those allowed by current ASP solvers. The translation relies on the introduction of auxiliary predicates and the main result shows that it preserves strong equivalence modulo the original signature.}, language = {en} } @inproceedings{HerreHummel2010, author = {Herre, Heinrich and Hummel, Axel}, title = {A paraconsistent semantics for generalized logic programs}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41496}, year = {2010}, abstract = {We propose a paraconsistent declarative semantics of possibly inconsistent generalized logic programs which allows for arbitrary formulas in the body and in the head of a rule (i.e. does not depend on the presence of any specific connective, such as negation(-as-failure), nor on any specific syntax of rules). For consistent generalized logic programs this semantics coincides with the stable generated models introduced in [HW97], and for normal logic programs it yields the stable models in the sense of [GL88].}, language = {en} } @inproceedings{Seipel2010, author = {Seipel, Dietmar}, title = {Practical Applications of Extended Deductive Databases in DATALOG*}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41457}, year = {2010}, abstract = {A wide range of additional forward chaining applications could be realized with deductive databases, if their rule formalism, their immediate consequence operator, and their fixpoint iteration process would be more flexible. Deductive databases normally represent knowledge using stratified Datalog programs with default negation. But many practical applications of forward chaining require an extensible set of user-defined built-in predicates. Moreover, they often need function symbols for building complex data structures, and the stratified fixpoint iteration has to be extended by aggregation operations. We present an new language Datalog*, which extends Datalog by stratified meta-predicates (including default negation), function symbols, and user-defined built-in predicates, which are implemented and evaluated top-down in Prolog. All predicates are subject to the same backtracking mechanism. The bottom-up fixpoint iteration can aggregate the derived facts after each iteration based on user-defined Prolog predicates.}, language = {en} } @inproceedings{Brass2010, author = {Brass, Stefan}, title = {Range restriction for general formulas}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41521}, year = {2010}, abstract = {Deductive databases need general formulas in rule bodies, not only conjuctions of literals. This is well known since the work of Lloyd and Topor about extended logic programming. Of course, formulas must be restricted in such a way that they can be effectively evaluated in finite time, and produce only a finite number of new tuples (in each iteration of the TP-operator: the fixpoint can still be infinite). It is also necessary to respect binding restrictions of built-in predicates: many of these predicates can be executed only when certain arguments are ground. Whereas for standard logic programming rules, questions of safety, allowedness, and range-restriction are relatively easy and well understood, the situation for general formulas is a bit more complicated. We give a syntactic analysis of formulas that guarantees the necessary properties.}, language = {en} } @inproceedings{ZeilingerMuttiStreckeretal.2006, author = {Zeilinger, Gerold and Mutti, Maria and Strecker, Manfred and Rehak, Katrin and Bookhagen, Bodo and Schwab, Marco}, title = {Integration of digital elevation models and satellite images to investigate geological processes.}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7063}, year = {2006}, abstract = {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 1km3 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, Universit{\"a}t 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.
Dokument 1: Foliensatz | Dokument 2: Abstract
Interdisziplin{\"a}res Zentrum f{\"u}r Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006}, language = {en} } @inproceedings{OhrnbergerWassermannRichter2006, author = {Ohrnberger, Matthias and Wassermann, Joachim and Richter, Gudrun}, title = {Automatic detection and classification of seismic signals for monitoring purposes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7294}, year = {2006}, abstract = {Interdisziplin{\"a}res Zentrum f{\"u}r Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006}, language = {en} } @inproceedings{PoppBlaumDomptailetal.2006, author = {Popp, Alexander and Blaum, Niels and Domptail, Stephanie and Herpel, Nicole and Gr{\"o}ngr{\"o}ft, Alexander and Hoffman, T. T. and J{\"u}rgens, Norbert and Milton, Sue and Nuppenau, Ernst-August and Rossmanith, Eva and Schmidt, Michael and Vogel, Melanie and Vohland, Katrin and Jeltsch, Florian}, title = {From satellite imagery to soil-plant interactions}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7302}, year = {2006}, abstract = {Decisions for the conservation of biodiversity and sustainable management of natural resources are typically related to large scales, i.e. the landscape level. However, understanding and predicting the effects of land use and climate change on scales relevant for decision-making requires to include both, large scale vegetation dynamics and small scale processes, such as soil-plant interactions. Integrating the results of multiple BIOTA subprojects enabled us to include necessary data of soil science, botany, socio-economics and remote sensing into a high resolution, process-based and spatially-explicit model. Using an example from a sustainably-used research farm and a communally used and degraded farming area in semiarid southern Namibia we show the power of simulation models as a tool to integrate processes across disciplines and scales.}, language = {en} } @inproceedings{RossmanithBlaumKeiletal.2006, author = {Rossmanith, Eva and Blaum, Niels and Keil, Manfred and Langerwisch, F. and Meyer, Jork and Popp, Alexander and Schmidt, Michael and Schultz, Christoph and Schwager, Monika and Vogel, Melanie and Wasiolka, Bernd and Jeltsch, Florian}, title = {Scaling up local population dynamics to regional scales}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7320}, year = {2006}, abstract = {In semi-arid savannas, unsustainable land use can lead to degradation of entire landscapes, e.g. in the form of shrub encroachment. This leads to habitat loss and is assumed to reduce species diversity. In BIOTA phase 1, we investigated the effects of land use on population dynamics on farm scale. In phase 2 we scale up to consider the whole regional landscape consisting of a diverse mosaic of farms with different historic and present land use intensities. This mosaic creates a heterogeneous, dynamic pattern of structural diversity at a large spatial scale. Understanding how the region-wide dynamic land use pattern affects the abundance of animal and plant species requires the integration of processes on large as well as on small spatial scales. In our multidisciplinary approach, we integrate information from remote sensing, genetic and ecological field studies as well as small scale process models in a dynamic region-wide simulation tool.
Interdisziplin{\"a}res Zentrum f{\"u}r Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006.}, language = {en} } @inproceedings{GebserHinrichsSchaubetal.2010, author = {Gebser, Martin and Hinrichs, Henrik and Schaub, Torsten and Thiele, Sven}, title = {xpanda: a (simple) preprocessor for adding multi-valued propositions to ASP}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41466}, year = {2010}, abstract = {We introduce a simple approach extending the input language of Answer Set Programming (ASP) systems by multi-valued propositions. Our approach is implemented as a (prototypical) preprocessor translating logic programs with multi-valued propositions into logic programs with Boolean propositions only. Our translation is modular and heavily benefits from the expressive input language of ASP. The resulting approach, along with its implementation, allows for solving interesting constraint satisfaction problems in ASP, showing a good performance.}, language = {en} }