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1.
Patrick DAstous Franoise Dtienne Willemien Visser Pierre N. Robillard 《Design Studies》2004,25(6):625-655
By contrast to design meetings, design evaluation meetings (DEMs) have generally been considered as situations in which, according to DEM methodologies, design activities are quite marginal. In a study of DEMs in software development, i.e. in technical review meetings following a particular review methodology, we showed: (i) the occurrence of design activities as part of an argumentation process; (ii) the relative importance of cognitive synchronisation as a prerequisite for evaluation; (iii) the important role played in evaluation by argumentation that makes explicit the underlying design rationale (DR). On the basis of our results, we discuss the potential for using DR methodologies in this kind of meetings. 相似文献
2.
Prof. Dr.-Ing. Andreas Visser Dipl.-Ing. Dipl.-Oec. Frank W. Peinemann 《Forschung im Ingenieurwesen》1996,62(6):149-160
Zusammenfassung Es werden die prinzipiellen Einsatzm?glichkeiten neuronaler Netwwerke zur Modellbildung, Steuerung und Regelung von Robotern
sowie zur Unterstützung sensomotorischer Aktionen dargelegt. Einige ausgew?hlte neuronale Regelungskonzepte werden vorgestellt
und auf ihre Stabilit?t, Robustheit, Genauigkeit sowie Echtzeitf?higkeit hin untersucht. Ferner wird gezeigt, wie sich neuronale
Regelungskonzepte in industrielle Robotersteuerungen integrieren lassen. 相似文献
3.
J. J. Quist W. J. A. Dhert W. Visser F. C. Oner A. J. Verbout B. P. Meij H. A. W. Hazewinkel 《Journal of materials science. Materials in medicine》1995,6(12):731-738
In the present study the potential of Polyactive® bilayer sheets in the prevention of scar tissue formation after spinal surgery was investigated. Eight adult beagle dogs underwent 3 laminectomies at three levels (L2, L4 and L6). According to a randomized implantation schedule a Polyactive® sheet or autogenous fat graft was placed in the defect. The third site served as a control without implant. After 4 or 12 weeks (4 dogs per period) the dogs were sacrificed and histological sections were prepared. The Polyactive® treated defects showed partial closure by newly formed bone. The Polyactive® was encapsuled by a thin fibrous tissue layer. Ventral to the defect, dense fibrous tissue was present which was separated from the dura by the Polyactive® sheet in all cases. In some cases fibrous tissue was present between the implant capsule and the dura. In the fat graft group there were no signs of closure of the defect but most sites showed fibrous tissue at the edges of the graft, which was in 4 sites continous with the dura mater. Fibrosis and degeneration of the fat grafts were seen. All control defects showed partial closure by newly formed bone, and ventral to the defect extensive fibrous tissue, which was in 50% continous with the dura mater. Other sections showed loose connective tissue in contact with the dura mater. It is concluded that Polyactive® has a potential as a mechanical barrier in the prevention of adhesions between the dorsal spinal muscles and the dura mater. 相似文献
4.
M Visser DP Kiel J Langlois MT Hannan DT Felson PW Wilson TB Harris 《Canadian Metallurgical Quarterly》1998,49(5-6):745-747
Aim of the study was investigate the cross-sectional relationship between body composition and bone mineral density (BMD) in very old men and women. The study sample consisted of 504 women and 285 men, aged 72-93 yr, participating in examination 22 (1992-1993) of the Framingham Heart Study. Total body BMD, regional BMD, and soft-tissue body composition was measured by dual-energy X-ray absorptiometry. Both muscle mass and percentage body fat were positively associated with total body BMD in women. After adjustment for age, physical activity, smoking status, estrogen use, and thiazide use, BMD increased with increasing tertile of muscle mass (p = 0.007) and with increasing tertile of percentage body fat (p = 0.0001) in women. In men muscle mass, not percentage body fat, was positively associated with BMD. After adjustment for potential confounders, BMD remained associated with muscle mass only (p = 0.02). These results were similar for leg BMD and arm BMD. The study suggests that the influence of muscle and fat mass on bone mineral density is different between very old men and women. 相似文献
5.
Walking tracks of Colorado potato beetles,Leptinotarsa decemlineata Say, were recorded on a locomotion-compensator in response to wind, odors of host plantsSolanum tuberosum L. and nonhost plantsLycopersicon hirsutum f.glabratum C.H. Mull, and to mixtures of these plant species. Host-plant odor induced positive anemotactic responses in starved females, whereas odor of the nonhostL. hirsutum was neither repellent nor attractive. The attractiveness of host-plant odor, however, was neutralized in the odor blend of plant species. Masking the attractive host-plant odor will hinder the beetle's searching for host-plant patches, and this principle may be exploited in pest control by mixed cropping.The locomotion-compensator was constructed with financial support from the Foundation for Fundamental Biological Research (BION), which is subsidized by the Netherlands Organization for the Advancement of Pure Research (ZWO), grant 14-02-02. The first author was supported by a grant from the French Ministry of Industry and Research. 相似文献
6.
Olfactory coding in the perception of semiochemicals 总被引:4,自引:0,他引:4
Information processing in the olfactory pathway underlying the perception of semiochemicals by insects is discussed. Both the chemical message for mates and the message for food consist of blends of chemicals. Olfactory receptors in an insect species are tuned to the detection of those compounds which comprise such chemical messages for that species. The classification of receptors as specialists or generalists coincides with two concepts of information processing, i.e., labeled lines and across-fiber patterns, respectively. The olfactory code coming from antennal receptors inPieris brassicae larvae is a combination of labeled lines and across-fiber patterning. When antennae of adult Colorado potato beetles,Leptinotarsa decemlineata, are stimulated by binary mixtures of leaf odor components, the pattern of neural activities in the olfactory receptors shows some separation into two channels, quantitative versus qualitative detection. The separation is complete in the antennal lobe of this beetle.Presented at the Symposium on Insect Chemical Communications: Unifying Concepts. ACS 194th National Meeting, New Orleans, Louisiana, August 31, 1987. 相似文献
7.
Somsen GW Hooijschuur EW Gooijer C Brinkman UA Velthorst NH Visser T 《Analytical chemistry》1996,68(5):746-752
An on-line postcolumn extraction module was used in conjunction with a solvent elimination interface for the semi-on-line coupling of reversed-phase liquid chromatography (RP-LC) and Fourier transform infrared spectrometry (FT-IR). The extraction module consisted of a phase segmentor, an extraction coil, and a phase separator. Dichloromethane was used as extraction solvent. The organic phase delivered by the separator was evaporated by a spray-jet assembly that simultaneously deposited the extracted analytes onto a zinc selenide window, which was subsequently analyzed by FT-IR microscopy. The method is evaluated by studying parameters such as postcolumn band broadening, phase separation efficiency, evaporation efficiency, extraction yield, eluent composition, and use of nonvolatile buffer salts. Good-quality spectra were obtained for test compounds (phenylureas and quinones), which were separated by RP-LC using a buffered eluent with high water content. Large-volume injections allowed FT-IR detection at the submicrogram per milliliter level. 相似文献
8.
Benjamin Balaguer Stephen Balakirsky Stefano Carpin Arnoud Visser 《Autonomous Robots》2009,27(4):449-464
This paper presents the map evaluation methodology developed for the Virtual Robots Rescue competition held as part of RoboCup.
The procedure aims to evaluate the quality of maps produced by multi-robot systems with respect to a number of factors, including
usability, exploration, annotation and other aspects relevant to robots and first responders. In addition to the design choices,
we illustrate practical examples of maps and scores coming from the latest RoboCup contest, outlining strengths and weaknesses
of our modus operandi. We also show how a benchmarking methodology developed for a simulation testbed effortlessly and faithfully
transfers to maps built by a real robot. A number of conclusions may be derived from the experience reported in this paper
and a thorough discussion is offered. 相似文献
9.
Eric Bouwers Martin Bravenboer Eelco Visser 《Electronic Notes in Theoretical Computer Science》2008,203(2):85
A wide range of parser generators are used to generate parsers for programming languages. The grammar formalisms that come with parser generators provide different approaches for defining operator precedence. Some generators (e.g. YACC) support precedence declarations, others require the grammar to be unambiguous, thus encoding the precedence rules. Even if the grammar formalism provides precedence rules, a particular grammar might not use it. The result is grammar variants implementing the same language. For the C language, the GNU Compiler uses YACC with precedence rules, the C-Transformers uses SDF without priorities, while the SDF library does use priorities. For PHP, Zend uses YACC with precedence rules, whereas PHP-front uses SDF with priority and associativity declarations.The variance between grammars raises the question if the precedence rules of one grammar are compatible with those of another. This is usually not obvious, since some languages have complex precedence rules. Also, for some parser generators the semantics of precedence rules is defined operationally, which makes it hard to reason about their effect on the defined language. We present a method and tool for comparing the precedence rules of different grammars and parser generators. Although it is undecidable whether two grammars define the same language, this tool provides support for comparing and recovering precedence rules, which is especially useful for reliable migration of a grammar from one grammar formalism to another. We evaluate our method by the application to non-trivial mainstream programming languages, such as PHP and C. 相似文献
10.