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91.
Real time discrete shading 总被引:1,自引:1,他引:0
A shading technique for voxel-based images, termedcongradient shading, is presented. As the surface information is not available in voxel representation, the surface normal must be recovered from the 3D discrete voxel map itself. The technique defines the normal as one of a finite set of neighborhood-estimated gradients and can thus employ precalculated look-up tables. Furthermore, a table-driven mechanism permits changing the light source parameters by merely redefining the look-up table. The technique uses only simple arithmetic operations and is thus suitable for hardware implementation. Since it has been implemented not as a post-processor, but as part of the projection pipeline of the cube architecture, congradient shading can be executed in real time. Two versions of the technique in real time. Two versions of the technique have been conceived and implemented:unidirectional shading, in which the gradient is estimated only from neighborhoods along the scan-lines;bidirectional shading, in which both horizontal and vertical components of the gradient are considered. In spite of the simplicity of the technique, the results are practically indistinguishable from images generated by conventional techniques.This work was supported by the National Science Foundation under grants DCR 8603603, CCR 8743478, CCR 8717016, and MIP 8805130 相似文献
92.
R. D. Roberts, M. Zeidner, and G. Matthews (see record 2001-10055-001) have carefully examined the controversial issue of whether emotional intelligence (EI) should be classified as an intelligence and whether EI's constructs meet the same psychometric standards as general intelligence's constructs. This article casts their efforts into the framework of both historical and modern IQ-testing theory and research. It details David Wechsler's attempts to integrate EI into his tests and how his conception of a good clinician would be that of an emotionally intelligent clinician. Current theories and research on IQ also have a role in EI beyond what Roberts et al. described, including J. L. Horn's (1989) expanded model and A. R. Luria's (1966) neuropsychological research, and better criteria than the Armed Services Vocational Aptitude Battery should be used in future EI studies. The authors look forward to more research being conducted on EI, particularly in future performance-based assessments. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
93.
The model studied in this paper captures the combined effects of finite and infinite source traffic-often used to model interactive and batch traffic, respectively-when they contend for a single server resource. The finite source traffic is modeled by heterogeneous finite sources, the infinite source traffic by a stationary Poisson process, and the single server is assumed to have exponentially distributed service times with distinct service rates for the different customer types. All customers share a common queue and are serviced in FIFO order. A special case of this model where theN finite sources are identical combines two fundamental and widely used models (the repairman andM/M/1 models) in a natural manner. Regardless of the homogeneous or heterogeneous nature of the finite sources, the combined source model is not product form due to the realistic assumption that service rates are distinct for different customer types (batch and interactive traffic typically have different CPU processing requirements). In this paper, we show how to recursively calculate all mean quantities of interest in an approximate but quite accurate manner for the general heterogeneous model. The accuracy of the recursive technique is established in part by contrasting the approximate solution to simulation results for a wide parameter range, and in part by studying the asymptotic behavior of the approximation. 相似文献
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95.
96.
Doz. Dr. J. Zajíc Dr. M. Bare K. Kaufman 《European Journal of Lipid Science and Technology》1970,72(10):865-870
Effect of Fatty Acid Configuration on the Properties of Soap The effect of configuration of the hydrophobic chain of fatty acids C10–C18 on the properties of their alkali salts was studied. Furthermore, the effect of temperature on critical micelle concentration (CMC) and on alteration of surface tension at CMC, as well as the effect of chain length of the hydrophobic part on CMC were determined. At the same time, the effect of double and cis-trans configuration on CMC was studied. Also the foaming ability of the individual soaps and foam stability as well as the stability of the soaps were investigated. 相似文献
97.
Ribeiro P.C. Williamson S.J. Kaufman L. 《IEEE transactions on bio-medical engineering》1988,35(7):551-560
Recently developed small arrays of SQUID- (superconducting quantum interference device) based magnetic sensors can, if appropriately placed, locate the position of a confined biomagnetic source without moving the array. A technique is presented having a relative accuracy of about 2% for calibrating such sensors having detection coils with the geometry of a second-order gradiometer. The effects of calibration error and magnetic noise on the accuracy of locating an equivalent current dipole source in the human brain are investigated for five- and seven-sensor probes and for a pair of seven-sensor probes. With a noise level of 5% of peak signal, uncertainties of about 20% in source strength and depth for a five-sensor probe are reduced to 8% for a pair of seven-sensor probes, and uncertainties of about 15 mm in lateral position are reduced to 1 mm for the configuration considered 相似文献
98.
Ilmoniemi R.J. Williamson S.J. Kaufman L. Weinberg H.J. Boyd A.D. 《IEEE transactions on bio-medical engineering》1988,35(7):561-564
A piece of thin acupuncture needle lodged under the right scapula of a patient could not be found in surgical procedures accompanied by studies of 30 standard X-ray images. To locate it, the authors mapped the magnetic field component normal to a plane lying above the object, using a superconducting quantum interference device (SQUID). Assuming that the needle could be modeled as a magnetic dipole, it was possible to infer its lateral position, depth, orientation, and magnetic moment. With this information, directed CT scans, high resolution X-ray films, and the subsequent surgical removal of the needle proved that it could be located in the body with an accuracy of about 3 mm 相似文献
99.
Brett Jack Fontana Raymond P. Walsh Peter J. Thouret Wolfgang E. Gerber Max Kaufman Rudolph Thorington Luke 《Industry Applications, IEEE Transactions on》1981,(2):210-216
The design considerations for filaments in energy conserving incandescent lamps are described. Such lamps require compact high emissivity filaments to absorb infrared radiation reflected from heat mirrored focusing envelopes. The relationships between the electrical parameters in the radiation returning environment and in the clear surroundings are developed. Efficiency experiments with filaments of various geometries under conditions of radiation return were performed. A highly compact coiled coil filament seems most promising for development. A calculation is presented of the filament emissivity as a function of spacing of the windings in a coil. Measurements of the emissivity as a function of the pitch of a coiled coil filament agree with the calculation. 相似文献
100.