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91.
A Bayesian approach to diagnosis and prognosis using built-in test   总被引:3,自引:0,他引:3  
Accounting for the effects of test uncertainty is a significant problem in test and diagnosis, especially within the context of built-in test. Of interest here, how does one assess the level of uncertainty and then utilize that assessment to improve diagnostics? One approach, based on measurement science, is to treat the probability of a false indication [e.g., built-in-test (BIT) false alarm or missed detection] as the measure of uncertainty. Given the ability to determine such probabilities, a Bayesian approach to diagnosis, and by extension, prognosis suggests itself. In the following, we present a mathematical derivation for false indication and apply it to the specification of Bayesian diagnosis. We draw from measurement science, reliability theory, signal detection theory, and Bayesian decision theory to provide an end-to-end probabilistic treatment of the fault diagnosis and prognosis problem.  相似文献   
92.
Boundary cell-based acceleration for volume ray casting   总被引:4,自引:0,他引:4  
Several effective acceleration techniques for volume rendering offer efficient means to skip over empty space, providing significant speedup without affecting image quality. The effectiveness of such an approach depends on its ability to accurately estimate the object boundary inside a volume with minimal computational overhead. We propose a novel boundary cell-based acceleration technique for ray casting which skips over empty space by accurately calculating the intersection distance for each ray. Very short distance estimation time is achieved by exploiting a projection template to calculate the parallel-projection values of each boundary cell and the coherency of adjacent cells. Since no hardware acceleration is used, the projection procedure can also be efficiently parallelized. Experimental results are provided to demonstrate the performance of our new algorithm.  相似文献   
93.
Fast Hybrid Approach for Texturing Point Models   总被引:1,自引:0,他引:1  
We present three methods for texturing point models from sample textures. The first method, the point parameterization method, uses a fast distortion‐bounded parameterization algorithm to flatten the point model's surface into one or more 2D patches. The sample texture is mapped onto these patches and alpha blending is used to minimize the discontinuity in the gaps between the patches. The second method is based on neighborhood matching where a color is assigned to each point by searching the best match within an irregular neighborhood. The hybrid method combines the former two methods, capitalizing on the advantages of both. The point parameterization method is used first to color most of the points, and the point neighborhood‐matching method is then applied to the points belonging to the gaps between the parameterized patches to minimize the discontinuity. We opt for fast texture generation, while some discontinuities may appear in the gaps of anisotropic textures.  相似文献   
94.
Thin films of Ba1?x Sr x Ti1+y O3+z (BST), were fabricated using both by RF-magnetron sputtering and MOCVD to demonstrate application to high frequency devices. Precise control of composition and microstructure is critical for the production of (Ba x Sr1?x )Ti1+y O3+z (BST) dielectric thin films with the large dependence of permittivity on electric field, low losses, and high electrical breakdown fields that are required for successful integration of BST into tunable high frequency devices. Here we review results on composition-microstructure-electrical property relationships of polycrystalline BST films produced by magnetron sputter deposition that are appropriate for microwave devices such as phase shifters. BST films with a multilayer structure were also developed with different Ti-elemental ratio in each layer to minimize losses and leakage current. Interfacial contamination from C and H species was studied and implications on electrical properties are highlighted. Finally, York's group at the University of California-Santa Barbara successfully integrated our BST films onto phase shifter arrays. The results show potential of BST films in such applications. Results from initial work on the integration of Cu-electrodes with BST films are also presented.  相似文献   
95.
The springback and anelastic behavior of selected Mg alloys were investigated as a function of thermo-mechanical state and loading conditions by strain-recovery experiments in three-point bending. The observed stress relaxations were primarily due to recoverable microstructural relaxations and the transformation of linear-elastic strains to recoverable time-dependent anelastic strains. This transformation occurs by thermally activated dislocation motion or reversible twin movement and influences the magnitude of the springback effect. The amount of anelastic strain observed during stress relaxation experiments was found to depend on four factors: initial dislocation density (cold work), applied strain levels, temperature, and holding time at fixed strain levels.  相似文献   
96.
The use of the Internet for conducting research has found that the level of anonymity intrinsic to web-based surveys is useful in deterring various participant biases. Though, concerns about Internet privacy could interfere with the effects of perceived anonymity and influence how a person responds. In this study, participants were asked to take an Internet survey and then were randomly assigned to conditions with varying degrees of implied privacy in which they answered questions about their desire for casual sex (sociosexuality) and their lifetime sexual partners. Only in the condition without any threat to the participant’s anonymity was there no difference between men and women’s reports of their sexual behavior. However, in every condition men reported having a significantly higher sociosexuality than women. Findings are consistent with both the biologic and gender-biased explanations in differences of self-report for sexual information. Implications for social constraints and Internet based research are discussed.  相似文献   
97.
Automatic photo enhancement is one of the long‐standing goals in image processing and computational photography. While a variety of methods have been proposed for manipulating tone and colour, most automatic methods used in practice, operate on the entire image without attempting to take the content of the image into account. In this paper, we present a new framework for automatic photo enhancement that attempts to take local and global image semantics into account. Specifically, our content‐aware scheme attempts to detect and enhance the appearance of human faces, blue skies with or without clouds and underexposed salient regions. A user study was conducted that demonstrates the effectiveness of the proposed approach compared to existing auto‐enhancement tools.  相似文献   
98.
The Food System     
Shelley Jordon describes her artwork as celebrating “the power and the beauty of domestic spaces and objects…culled from daily life.” Food is among the most basic of daily human needs, yet what is most basic often gets overlooked. Alpenrose, her image of a breakfast table, brings this human need to the fore, as authors Ka-meshwari Pothukucki and Jerome L. Kaufman argue that food systems need a place among the concerns of planners.

The artist, who is an associate professor of art at Oregon State University, resides in Portland, Oregon. Her works can be found in galleries and private collections throughout the West Coast.

Planning lays claim to being comprehensive, future-oriented, and public-interest driven, and of wanting to enhance the livability of communities. It is concerned with community systems—such as land use, housing, transportation, the environment, and the econ-omy—and their interconnections. The food system, however, is notable by its absence from most planning practice, research, and education. We present evidence for the limited presence of the food system in planning's list of concerns by scanning leading journals, texts, and classic writings, and by reporting on a survey of 22 U.S. city planning agencies. We analyze this low level of attention and discuss reasons and ideas for planning involvement to strengthen community food systems.1  相似文献   
99.
This paper discusses the effects of non-Lambertian reflection from a homogeneous surface on remote sensing of the surface reflectance and vegetation index from a satellite. Remote measurement of the surface characteristics is perturbed by atmospheric scattering of sun light. This scattering tends to smooth the angular dependence of non-Lambertian surface reflectances, an effect that is not present in the case of Lambertian surfaces. This effect is calculated to test the validity of a Lambertian assumption used in remote sensing. For the three types of vegetations considered in this study, the assumption of Lambertian surface can be used satisfactorily in the derivation of surface reflectance from remotely measured radiance for a view angle outside the backscattering region. Within the backscattering region, however, the use of the assumption can result in a considerable error in the derived surface reflectance. Accuracy also deteriorates with increasing solar zenith angle. The angular distribution of the surface reflectance derived from remote measurements is smoother than that at the surface. The effect of surface non-Lambertianity on remote sensing of vegetation index is very weak. Since the effect is similar in the visible and near infrared part of the solar spectrum for the vegetations treated in this study, it is canceled in deriving the vegetation index. The effect of the diffuse skylight on surface reflectance measurements at ground level is also discussed.  相似文献   
100.
Remote sensing of suspended sediments and shallow coastal waters   总被引:8,自引:0,他引:8  
Ocean color sensors were designed mainly for remote sensing of chlorophyll concentrations over the clear open oceanic areas (Case 1 water) using channels between 0.4-0.86 /spl mu/m. The Moderate Resolution Imaging Spectroradiometer (MODIS) launched on the National Aeronautics and Space Administration Terra and Aqua spacecrafts is equipped with narrow channels located within a wider wavelength range between 0.4-2.5 /spl mu/m for a variety of remote sensing applications. The wide spectral range can provide improved capabilities for remote sensing of the more complex and turbid coastal waters (Case 2 water) and for improved atmospheric corrections for ocean scenes. We describe an empirical algorithm that uses this wide spectral range to identify areas with suspended sediments in turbid waters and shallow waters with bottom reflections. The algorithm takes advantage of the strong water absorption at wavelengths longer than 1 /spl mu/m that does not allow illumination of sediments in the water or a shallow ocean floor. MODIS data acquired over the east coast of China, west coast of Africa, Arabian Sea, Mississippi Delta, and west coast of Florida are used.  相似文献   
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