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1.
Ethan Scarl 《Annals of Mathematics and Artificial Intelligence》1994,11(1-4):493-509
The concept of diagnostic accuracy is examined and redefined to support specific criteria for sensor placement. If the correctness of diagnoser operation is assumed, then any failure to diagnose accurately must be attributable to an inadequacy of sensor data. Inaccuracy in diagnoses can be expressed solely in terms of additional candidates whose faults cannot be ruled out. With ambiguity as the determiner of the quality of a diagnosis, user-defined diagnosability requirements can be expressed in terms of the types and instances of components which are permissible exceptions to perfect diagnosis. This requires a working diagnoser and a simulator, along with sets of system configurations, component fault modes, potentially measurable parameters, and uniqueness requirements for fault isolation. From these, the diagnosability of individual components can be determined for a particular attached subset of the available sensors. An optimum sensor assignment is one that satisfies the most requirements with a fixed number of sensors or, conversely, that minimizes the sensor requirements to achieve a given threshold of diagnosability. The considerable complexity of this search is reduced by exploiting sensor set minimality, structural knowledge, and diagnosis-free extension to the system level. Global optimization and sensor allocation do not add to the number of diagnoses required for diagnosability analysis. Finally, corrective measures are discussed for use when residual costs remain too high, or when redundancy is too low.In support of NASA's Marshall Space Flight Center and the Space Station Freedom Advanced Development Program under NASA contract number NAS 8-37200. 相似文献
2.
Abstract— Recent commercial liquid‐crystal‐display (LCD) televisions are larger and brighter than traditional televisions, thus impacting the viewing conditions in which they are viewed. These changes in viewing conditions may require different electro‐optical transfer functions (EOTFs) for LCD TVs than those for conventional TVs. Here, the way various EOTFs affect the preferred image quality of test images with changes in brightness and surround illumination conditions are examined. The first method used a gain, offset, and gamma (GOG) function with a range of gamma values, and the second method altered the intrinsic EOTFs. Image preference for the simulated EOTFs was determined using a paired‐comparison experiment for ten images. The first experiment took place in a darkened room at two display luminance levels. The results indicated that a gamma of 1.6 was most preferred overall although more so at a lower screen luminance level. In a second experiment, the procedure was repeated with a dim surround of 10% of the display's white point. With this surround, preference for a gamma value of around 1.6 at both screen luminance levels was more enhanced. These results indicated that image preference for different EOTFs is dependent on display luminance and that this dependence is maintained with a dim surround. 相似文献
3.
The San Diego County Water Authority of California has initiated planning for coastal desalination facilities to augment their water supplies. Integration of the different water qualities from these facilities into existing pipelines must be achieved. This investigation determined whether, and to what degree, consumers can discriminate between desalinated seawater and imported water supplies and how these investigations can contribute to decision making regarding the need for construction of facilities to blend such supplies prior to delivery. Based upon the results of the flavour profile analysis panel and the consumer evaluation sessions, it was concluded that free chlorine versus chloramine disinfection or different concentrations of disinfectants did not significantly affect consumer perception of the taste and odour of desalinated seawater or blends with Colorado River water and State project water. Consumers were able to discern between desalinated seawater and imported water, preferring imported water when forced to make a choice. However, the investigators did not believe that the difference in consumer perception was significant enough to warrant special blending facilities to mitigate the relatively minor aesthetic quality differences between imported water supplies and desalinated seawater. 相似文献
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M Albert C Athanassopoulos LB Auerbach D Bauer R Bolton B Boyd RL Burman I Cohen DO Caldwell BD Dieterle JB Donahue AM Eisner A Fazely FJ Federspiel GT Garvey RM Gunasingha V Highland J Hill R Imlay K Johnston WC Louis A Lu AK Mann J Margulies K McIlhany W Metcalf RA Reeder V Sandberg M Schillaci D Smith I Stancu W Strossman MK Sullivan GJ VanDalen W Vernon YX Wang DH White D Whitehouse D Works Y Xiao S Yellin 《Canadian Metallurgical Quarterly》1995,51(3):R1065-R1069
6.
This paper surveys recent research in deliberative real-time artificial intelligence (AI). Major areas of study have beenanytime algorithms, approximate processing, and large system architectures. We describe several systems in each of these areas, focusing both on progress within the field, and the costs, benefits and interactions among different problem and algorithm complexity limitations used in the surveyed work. 相似文献
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8.
Do Alluvial Sand Dunes Create Energetic Refugia for Benthic Fishes? An Experimental Test with the Endangered Pallid Sturgeon 下载免费PDF全文
River modifications have altered critical habitats for fishes at a variety of spatial scales and caused global declines of many fluvial species. At small spatial scales (<1 m2), alluvial sand dunes, a ubiquitous habitat in highly modified rivers, are thought to provide energetic relief for benthic fishes in energetically costly riverine landscapes created by water flow. However, use of alluvial dune habitat is not well understood, and it is unclear whether dunes provide refuge that effectively reduces energetic costs. We designed a scale‐relevant experiment to examine the energetic responses associated with sand dune habitat in rivers. We tested whether the US federally endangered pallid sturgeon (Scaphirhynchus albus ), a benthic fish commonly associated with sand dunes, experienced reduced energetic costs with different configurations of simulated sand dune habitat. We quantified mass specific oxygen consumption (M O2; mg O2 kg?1 h?1) using intermittent flow‐through respirometry for age‐0 sturgeon (140–170 mm) in front of a sand dune, behind a sand dune and in the absence of a sand dune at two velocities (25 and 50 cm s?1) commonly observed in field studies of sturgeon habitat use. Sturgeon displayed distinct station holding behaviours for each habitat configuration. Dune location did not affect energy expenditure, but sturgeon M O2 was on average 16–20% higher in the absence of a sand dune depending on dune configuration. M O2 was on average 14% higher at 50 cm s?1 compared with 25 cm s?1. Our results provide a potential mechanism for over two decades of research on why sturgeon and other benthic fishes exhibit selection for sand dune habitat in large rivers. Fishes that select main channel habitats may depend on energetic relief provided by sand dunes, especially when other forms of structure are not available. For this reason, alluvial sand dune habitat may be important to the persistence of benthic fishes in high flow environments. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
9.
A method is presented for determining the optical absorption coefficient, or the imaginary refractive index, of particulate material that has been collected from aerosols or hydrosols by means of filtration. The method, based on the Kubelka-Munk theory of diffuse reflectance, is nondestructive and requires no other knowledge of the sample than the amount present, the specific gravity, and an estimate of the real index of refraction. The theoretical development of the method is discussed along with an analysis of photometric and gravimetric errors. We test the method by comparing results obtained for powdered didymium glass with measurements made before the glass was crushed. An example of the method's application to the determination of the absorption coefficient of atmospheric dust at UV, visible, and near-IR wavelengths is also presented. 相似文献
10.
On the Wetting States of Low Melting Point Metal Galinstan® on Silicon Microstructured Surfaces 下载免费PDF全文