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201.
202.
In this paper, we explore the situation where no cardinal directions or globally available orientations are available and no metric estimates are given. This corresponds to the way many people perceive their environment and carry out spatial reasoning tasks. We consider three kinds of locally available information – proximity (nearest neighbor), relevance (different sets of neighbors) and distribution (alignments) – and we limit our interest to a universe of point objects. We show how the theory of manifolds and sheaves can be applied to the problem of combining locally available information of a qualitative nature into a global model of an environmental space. We then explore the limitations of the resulting global model if information capture is incomplete or uncertain. Finally, we note that some indeterminacy in the global model does not entail difficulties for a user, provided the reasoning task is appropriately constrained or appropriate additional information is used, such as an external reference. 相似文献
203.
世博会中的芬兰:建筑、设计和创造力芬兰一直是世界博览会积极的参与者。从第一届1851年伦敦世博会开始就已开始崭露头角,虽然当时作为俄国的一部分(芬兰 相似文献
204.
Fairén AG Davila AF Lim D Bramall N Bonaccorsi R Zavaleta J Uceda ER Stoker C Wierzchos J Dohm JM Amils R Andersen D McKay CP 《Astrobiology》2010,10(8):821-843
Mars has undergone three main climatic stages throughout its geological history, beginning with a water-rich epoch, followed by a cold and semi-arid era, and transitioning into present-day arid and very cold desert conditions. These global climatic eras also represent three different stages of planetary habitability: an early, potentially habitable stage when the basic requisites for life as we know it were present (liquid water and energy); an intermediate extreme stage, when liquid solutions became scarce or very challenging for life; and the most recent stage during which conditions on the surface have been largely uninhabitable, except perhaps in some isolated niches. Our understanding of the evolution of Mars is now sufficient to assign specific terrestrial environments to each of these periods. Through the study of Mars terrestrial analogues, we have assessed and constrained the habitability conditions for each of these stages, the geochemistry of the surface, and the likelihood for the preservation of organic and inorganic biosignatures. The study of these analog environments provides important information to better understand past and current mission results as well as to support the design and selection of instruments and the planning for future exploratory missions to Mars. 相似文献
205.
Marie-Paule Daniel Célia Mores Dibo-Cohen Luc Carité Patrice Boyer Michel Denis 《Spatial Cognition & Computation》2013,13(3):287-309
ABSTRACT Twenty outpatients who fulfilled the criteria for a diagnosis of schizophrenia and 28 control participants were invited to learn a route through a complex outdoor environment. They were then tested in tasks intended to explore various aspects of their memorized representation of the navigational episode. Compared to controls, the patients showed significant impairment in both the verbal production of route directions and the drawing of sketch maps. They referred to fewer landmarks and provided fewer directional instructions than the controls, while making a greater number of irrelevant comments. When invited to distinguish between photographs showing views of landmarks encountered along the route and distractors, they performed as well as the controls, and they had similar response times. However, when they were presented with pairs of actual photographs taken along the route, they displayed special difficulty in deciding which of the two landmarks was encountered first along the route. This difficulty in retrieving the sequential structure of the navigational episode suggests that the patients' memories were not accurately linked to one another in their mental representation of the route. These findings are interpreted in the context of current hypotheses about the hippocampal impairment that affects schizophrenic patients. 相似文献
206.
ISO performed a large variety of observing programmes on comets, asteroids and zodiacal light – covering about 1% of the archived
observations – with a surprisingly rewarding scientific return. Outstanding results were related to the exceptionally bright
comet Hale–Bopp and to ISO's capability to study in detail the water spectrum in a direct way. But many other results were
broadly recognised: Discovery of new molecules in comets, the studies of crystalline silicates, the work on asteroid surface
mineralogy, results from thermophysical studies of asteroids, a new determination of the asteroid number density in the main-belt
and last but not least, the investigations on the spatial and spectral features of the zodiacal light. 相似文献
207.
Helmut Lammer Eric Chassefière Özgür Karatekin Achim Morschhauser Paul B. Niles Olivier Mousis Petra Odert Ute V. Möstl Doris Breuer Véronique Dehant Matthias Grott Hannes Gröller Ernst Hauber Lê Binh San Pham 《Space Science Reviews》2013,174(1-4):113-154
The evolution and escape of the martian atmosphere and the planet’s water inventory can be separated into an early and late evolutionary epoch. The first epoch started from the planet’s origin and lasted ~500 Myr. Because of the high EUV flux of the young Sun and Mars’ low gravity it was accompanied by hydrodynamic blow-off of hydrogen and strong thermal escape rates of dragged heavier species such as O and C atoms. After the main part of the protoatmosphere was lost, impact-related volatiles and mantle outgassing may have resulted in accumulation of a secondary CO2 atmosphere of a few tens to a few hundred mbar around ~4–4.3 Gyr ago. The evolution of the atmospheric surface pressure and water inventory of such a secondary atmosphere during the second epoch which lasted from the end of the Noachian until today was most likely determined by a complex interplay of various nonthermal atmospheric escape processes, impacts, carbonate precipitation, and serpentinization during the Hesperian and Amazonian epochs which led to the present day surface pressure. 相似文献
208.
B. Ehmann L. Balázs É. Fülöp R. Hargitai P. Kabai B. Péley T. Pólya A. Vargha J. László 《Acta Astronautica》2011,68(9-10):1560-1566
This paper is about a pilot application of narrative psychological content analysis in the psychological status monitoring of Crew 71 of a space analog simulation environment, the Mars Desert Research Station (MDRS). Both the method and its theoretical framework, Scientific Narrative Psychology, are original developments by Hungarian psychologists [5] (László, 2008). The software was NooJ, a multilingual linguistic development environment [11] (Silberztein, 2008). Three measures were conceptualized and assessed: emotional status, team spirit and subjective physical comfort. The results showed the patterns of these three measures on a daily basis at group level, and allowed for detecting individual differences as well. The method is adaptable to languages involved in space psychology, e.g. Russian, French and German in addition to English. 相似文献
209.
Recent discoveries of planets orbiting several nearby solar-mass stars have focussed renewed attention on the frequency and evolution of planetary systems and their evolutionary precursors around both solar and intermediate (2 M/M 8) mass stars. As a result of a wealth of new observations at all wavelengths of the circumstellar material around the nearest of the young intermediate-mass stars, the so-called Herbig Ae/Be (HAeBe) stars, we are beginning to see how these systems are similar to the solar mass objects, and how they differ. A review of the recent literature is presented, including the evolutionary status of the stars, binary frequency and the star forming environment, the morphology of the circumstellar material, including the first direct detections of disks in Keplerian rotation around these objects, and mass loss and infall phenomena. Prospects for advances in this research area as a result of advances in instrumentation are reviewed. 相似文献
210.
The temperature and emissivity of infrared and submillimeter telescopes are basic parameters that drive the optical and thermal design of astronomical space projects. They determine also, among other parameters, the self-emission of the instrument and the photon noise produced by this radiation on the detectors. By comparing the telescope brightness with that of the sky in the 1m–1 cm wavelength range, general conditions for background limited photometry are derived. For <0.4 mm, temperature is the driving parameter, and for >0.4 mm, temperature and emissivity have equivalent importances. It can be shown on actual projects that these two regimes determine different optical and thermal concepts. Although based on a simplistic approach, this work intends to help designers to handle some basic system parameters of infrared and submillimeter instruments. 相似文献