Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2003
Populærvitenskapelig – Driftsassistanse 2002. Teigen avfallsanlegg, Nesodden kommune.
Ketil Haarstad
Forfattere
Ketil HaarstadSammendrag
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Sammendrag
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Forfattere
Holger LangeSammendrag
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Sammendrag
Reprints available in my office
Sammendrag
Living organisms in ecosystems are conceptualized as autonomous agents with a spectrum for their behavior. Ecosystems are described here as interacting multi-agent systems. Implementing such a system is a challenge for current hardware and software technology both technically and conceptually, in particular if one of the agents is human, either virtually within the system or as external participant and user (real human).Interfering with and manipulating the system occurs at arbitrary times during simulation, with a collection of choices to do that, rendering the details of the particular simulation fundamentally unpredictable.As a result, we have an open interactive system with tight feedback loops, for which new computer models (beyond the Universal Turing Machine) are required. We discuss some of the theoretical concepts for the appropriate software technology and shortly present one example of such a system, a forest simulator used by forest administrators.
Forfattere
Holger LangeSammendrag
High resolution digital elevation maps (DEMs) offer the investigation of multifractal properties of the spatial characteristics of river basins like the width function, and the determination of the relation between average slope and basin area.There have been a number of universality claims in this respect; the range of the scaling exponent for the slope-area relation seems to be narrow, and the multifractal spectrum of the width function is characterized by a single site-specific Lipschitz-Hlder exponent alpha, the spectrum having an envelope given by that of Peanos basin.Comparing 17 river basins covering two orders of magnitude in basin area, our findings do not confirm this universal character. In particular, the Lipschitz-Hlder exponent crucially depends on the resolution of the width function extraction; we show that it is easy to produce almost identical spectra for completely different basins when varying the resolution.The problem of interior points is also encountered. We adopt Venezianos modified calculation of f(alpha) in this case. The slope-area exponent covers a wide range of values which also include the pure random case. We thus question the usability of these measures as a classification tool for river basins. http://www.cosis.net/abstracts/EAE03/05246/EAE03-J-05246.pdf
Forfattere
Holger LangeSammendrag
For the intepretation of multifractal properties of experimental time series, two prominent procedures used are the double trace method (DTM) and the universal multifractal (UM) approach. We calculated multifractal spectra for a collection of long-term precipitation, air temperature and river discharge records, covering a wide range of spatial scales.Considering K(q) in this framework leads to an effective classification of dynamical behavior. Comparison of the DTM and UM methodologies, however, reveals substantial differences which make them difficult to reconcile. This is in particular true for the discharge case.The scaling exponent is generally larger in magnitude for the DTM and in some cases even extends into the non-analytical regime. Part of previous work thus could not be confirmed. Whether the description of river flow as multifractal process is feasible remains an open question. http://www.cosis.net/abstracts/EAE03/05092/EAE03-J-05092.pdf
Forfattere
Ketil HaarstadSammendrag
Det er ikke registrert sammendrag
Forfattere
Ketil HaarstadSammendrag
Det er ikke registrert sammendrag
Forfattere
Ketil HaarstadSammendrag
Det er ikke registrert sammendrag