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941.
During recent years, synthetic aperture radar (SAR) data have been increasingly used for flood mapping. New radar satellites especially, such as TerraSAR-X, Radarsat-2 and COSMO-SkyMed, provide high-resolution data with high potential for fast and reliable detection of inundated areas. This article compares three simple approaches to derive water areas from SAR data in relation to the German–Vietnamese project, Water-related Information System for the Sustainable Development of the Mekong Delta (WISDOM). Two methods are pixel based and use histogram-based grey-level thresholds, as well as a homogeneity criterion for classification. The third approach is object based and applies characteristic attributes of water objects such as grey value, texture and relations to neighbouring objects. Further discussed are the influence of a variation of the thresholds and the challenges to validate water masks derived from active remote-sensing data. We implemented one of the introduced approaches for surface water derivation in a water mask processor for automatic water mask calculation from radar satellite imagery (WaMaPro). This fully automatic processing chain was developed to process TerraSAR-X and Environmental Satellite Advanced Synthetic Aperture Radar (ENVISAT ASAR) imagery in order to meet the demands for automatic flood monitoring.  相似文献   
942.
Since many years the robotics community is envisioning robot assistants sharing the same environment with humans. It became obvious that they have to interact with humans and should adapt to individual user needs. Especially the high variety of tasks robot assistants will be facing requires a highly adaptive and user-friendly programming interface. One possible solution to this programming problem is the learning-by-demonstration paradigm, where the robot is supposed to observe the execution of a task, acquire task knowledge, and reproduce it. In this paper, a system to record, interpret, and reason over demonstrations of household tasks is presented. The focus is on the model-based representation of manipulation tasks, which serves as a basis for incremental reasoning over the acquired task knowledge. The aim of the reasoning is to condense and interconnect the data, resulting in more general task knowledge. A measure for the assessment of information content of task features is introduced. This measure for the relevance of certain features relies both on general background knowledge as well as task-specific knowledge gathered from the user demonstrations. Beside the autonomous information estimation of features, speech comments during the execution, pointing out the relevance of features are considered as well. The results of the incremental growth of the task knowledge when more task demonstrations become available and their fusion with relevance information gained from speech comments is demonstrated within the task of laying a table.  相似文献   
943.
Fluid-structure interaction (FSI) problems are of great relevance to many fields in engineering and applied sciences. One wide spread and complex FSI-subclass is the category that studies the instationary behavior of incompressible viscous flows and thin-walled structures exhibiting large deformations. Free surfaces often present an essential additional challenge for this class of problems. Prominent application areas are fluid sloshing in tanks and numerable problems in offshore engineering and naval architecture. Especially when partitioned strong coupling schemes are used in order to solve the coupled FSI problem the design of an appropriate overall computational approach including free surface effects is not trivial. In this paper a new so-called partitioned implicit free surface approach is introduced and embedded into a strong coupling FSI solver. For complex problem classes this approach is combined with the general elevation equation that is closed through a dimensionally reduced pseudo-structural approach. The presented approach shows the same stability properties as a full implicit approach but is by far more efficient—especially in the partitioned coupled case.  相似文献   
944.
Currently, electronic agents are being designed and implemented that, unprecedentedly, will be capable of performing legally binding actions. These advances necessitate a thorough treatment of their legal consequences. In our paper, we first demonstrate that electronic agents behave structurally similar to human agents. Then we study how declarations of intention stated by an electronic agent are related to ordinary declarations of intention given by natural persons or legal entities, and also how the actions of electronic agents in this respect have to be classified under German law. We discuss four different approaches of classifying agent declarations. As one of these, we propose the concept of an electronic person (i.e., agents with limited liability), enrolment of agents into an agent register, and agent liability funds as means to serve the needs of all contracting parties.  相似文献   
945.
This paper describes Bibster, a Peer-to-Peer system for exchanging bibliographic metadata among researchers. We show how Bibster exploits ontologies in data-representation, query formulation, query routing, and query result presentation. The Bibster system is freely available and is used by researchers across multiple organizations.  相似文献   
946.
947.
Joseph L. Steffen 《Software》1984,14(4):323-334
Debugging tools are usually highly machine and compiler dependent programs that are either impossible to move or require a tremendous effort to move to another machine. This paper describes Ctrace, a portable debugging tool for the C language that provides the same, easy-to-use debugging environment on all machines. A similar debugger can be written for any language. Ctrace is a preprocessor that inserts source language debugging code into the program before compilation that, at execution time, prints the text of each source language statement along with the values of variables it uses and modifies. Redundant trace output from program loops is detected and eliminated. Tracing can be limited to selected statements or functions. Ctrace has shown its usefulness and popularity by its installation on over 200, computers at Bell Laboratories. It has proven its portability by being used to test software on four different operating systems and nine different processors.  相似文献   
948.
The effect of molecular hydrogen on the formation of molecular carbonaceous species important for soot formation is studied through a combination of shock-tube experiments with high-repetition-rate time-of-flight mass spectrometry and detailed chemistry modeling. The experiment allows to simultaneously measure the concentration–time profiles for various species with a time resolution of 10 μs. Concentration histories of reactants and polyacetylene intermediates (C2xH2, x = 1–4) are measured during the pyrolysis of acetylene with and without H2 added to the gas mixture for a wide range of conditions. In the 1760–2565 K temperature range, reasonable agreement between the experiment and the model predictions for C2H2, C4H2, C6H2, and C8H2 is achieved. H2 addition leads to the depletion of important building blocks for particle formation, namely of polyacetylenes due to an enhanced consumption of important radicals by H2, which are required for the fast build-up of carbonaceous material.  相似文献   
949.
With the development of the new Swiss Ventafresh technology (Steffen, 2007 Steffen, H.P. April 2-4 2007. Presentation of the VENTAFRESH Disinfection and Packing Technology in Several Food Processing Applications, April 2-4, Fresno, CA: Proc. Intl. Water Technology Conference and OZONE V. Session D, paper 4 [Google Scholar]; Steffen et al., 2007a,b) that produces edible, packaged foods having much longer shelf-lives than are available by current technologies, new vistas in food service and restaurant service have become available. About 170 km outside of Madrid is a new food processing and packaging plant. Raw foodstuffs (spices, fruits, meats, vegetables, rice, potatoes, pasta, salads, etc.) are delivered to this plant where they are washed (in ozone-containing water), peeled, sliced, etc. Microwaveable packing trays are filled with ingredients of a complete meal and then sealed with a microwaveable plastic film (sometimes with modified atmospheres). Both the packing trays and the sealing film are disinfected using combinations of ozone and UV radiation. Individual meals are prepared and packaged, but are not precooked, then are delivered to five (currently) Crono Chef restaurants strategically located throughout Madrid (www.crono.tv). There are only waiters/waitresses. A customer entering a Crono Chef restaurant is seated, offered the usual libations, and given a menu of the meals stocked?–?in refrigerators, not frozen. The customer's selection is cooked fresh in one of many microwave ovens on the premises. Cheese and/or desserts follow, along with the usual after-dinner drinks, if desired. This new concept in food delivery can be extended to food service for large institutions, e.g., military installations, sporting events, hospitals, elder care facilities, schools, prisons, highway restaurants, and is available for franchising.  相似文献   
950.
Multi-technology platforms are an emerging and promising production technology. However, until now the conditions are unclear under which value creation with multi-technology platforms can be carried out more efficiently than with a system of stand-alone machines. This paper derives characteristic thresholds mathematically that describe points of equal advantageousness of both alternatives in terms of lot size and number of processes required to machine the workpiece. It is found that the progression of the characteristic thresholds is describable by three characteristic figures χ, ρ and ω. The findings emphasize the necessity of a significant reduction of processing times on multi-technology platforms.  相似文献   
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