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121.
ZHAN Xiao guoSenior engineer Yangtze River Scientific Research Institute Changjiang Water Resources Commission Wuhan China 《人民长江》2002,(Z1)
1 SpatialDataWarehouse1.1 FunctionsofSpatialDataWarehouseInordertomeettherequirementtospatialdata ,thedataderivedfromdifferentsubjectsaregroupedinuniformformatsaccordingtothethemesthatuserscareabout.Thespecialmodelsareestablishedtoprocessthedatainthevie… 相似文献
122.
Chakraborty DP 《Journal of the Society for Information Display》2006,14(10):921-926
Researchers have developed visual discrimination models (VDMs) that can predict a human observer's ability to detect a target object superposed on an image. These models incorporate sophisticated knowledge of the properties of the human visual system. In the predictive approach, termed conventional VDM usage, two input images with and without a target are analyzed by an algorithm that calculates a just-noticeable-difference (JND) index, which is a taken as a measure of the detectability of the target. A new method of using the VDM is described, termed channelized VDM, which involves finding the linear combination of the VDM-generated channels (which are not used in conventional VDM analysis) that has optimal classification ability between normal and abnormal images. The classification ability can be measured using receiver operating characteristic (ROC) or two alternative forced choice (2AFC) experiments, and in special cases they can also be predicted by signal detection theory (SDT) based model-observer methods. In this study simulated background and nodule containing regions were used to validate the new method. It was found that the channelized VDM predictions were in excellent qualitative agreement with human-observer validated SDT predictions. Either VDM method (conventional or channelized) has potential applicability to soft-copy display optimization. An advantage of any VDM-based approach is that complex effects, such as visual masking, are automatically accounted for, which effects are usually not included in SDT-based methods. 相似文献
123.
Reports an error in "Recovery of spatial alternation deficits following selective hippocampal destruction with kainic acid" by J. Patrick Kesslak and Fred H. Gage (Behavioral Neuroscience, 1986[Apr], Vol 100[2], 280-283). In the aforementioned article, the degrees of freedom reported in the Results section are incorrect. In the sixth paragraph on page 281, the second sentence should read as follows: Results of the ANOVA indicated a significant effect for surgical treatments. F(2, 25)=25.44, p1986-21445-001.) Examined whether the sympathetic ingrowth of superior cervical ganglion (SCG) fibers sprouting into the hippocampus following kainic acid (KA) lesion of CA3 and CA4 pyramidal cells in male Sprague-Dawley rats would contribute to behavioral recovery. 31 Ss were trained on a forced-choice task. After reaching criterion performance levels, Ss received either KA (8 nM/0.4 μl) or saline injections into the hippocampus and were again tested on the forced-choice task. Half of the Ss had their SCG removed 35 days after injections, and all were again tested on the forced-choice task. Analysis of variance (ANOVA) showed Ss receiving KA took significantly longer to reach criterion following injections. Removal of the SCG after recovery reintroduced the performance deficit of KA-treated Ss on the alternation task; no other group showed any effect for SCG removal. Results indicate that the SCG may have a modulatory effect in behavioral recovery, although other mechanisms may also be operating. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
124.
Using the photonic band gap in photonic crystals, the fundamental waveguide structures for the light wavelength range have been developed. Based on the fine structure of these many functional devices have been proposed by analytical or numerical simulation methods and the experiments of trial manufacture. In this paper, the treatment of chiral dielectric in the Condensed Node Spatial Network for the vector potential is explained, and we show the polarization plane rotation property in air‐hole and pillar type photonic crystal waveguide structures with the chiral medium substrate. Then, we show the fundamental advantage of the air‐hole type photonic crystal waveguide structure in application to a mode converter. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(1): 7–14, 2005; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20098 相似文献
125.
姚占勇 《山东工业大学学报》2007,37(6):79-82
采用有限差分的计算方法,分析了黄泛区公路地基在不同压实度和压实深度条件下的沉降规律,提出了地基的压实标准和处置技术措施.研究认为,对高度〈6m的路基,保证90%的压实度对减少路基的工后沉降变形至关重要.对高度〉6m的路基,提高地基压实度,特别是将压实度由90%提高到93%,对降低地基沉降的作用不大.加大地基的压实深度,与提高压实度表现出相似的规律性,但对降低地基沉降的效果更明显.应根据路基高度提出地基的压实控制标准.路基高度≤2m,地基表层30压实度应≥93%;路基高度2~6m,地基表层30压实度应≥90%;路基高度〉6m,地基表层30压实度应〉185%.指出采用强夯、冲击碾压实地基,是黄泛区经济有效的工程技术措施. 相似文献
126.
高敬 《稀有金属与硬质合金》1998,(1)
对奥地利普兰西公司作了简要介绍,并将我国的钨、钼产品标准和普兰百公司的钨、钼产品、规格进行了对比。根据差距提出了我国钨、钼产品今后的发展方向。 相似文献
127.
Ray-cast volume rendering accelerated by incremental trilinear interpolation and cell templates 总被引:3,自引:0,他引:3
Two related ideas for improving the speed of ray-cast volume rendering are studied in this paper. The first is an incremental algorithm for trilinear interpolation, a method commonly used in ray-cast volume rendering to calculate sample values. The incremental algorithm can expedite trilinear interpolation when many samples along a ray are located in one cell. The second is an efficient hybrid volume rendering restricted to parallel projection. In the preprocessing stage, acell template is created to store the information used by the incremental trilinear interpolation. When a cell is parallel projected, the information is retrieved from the template to compute the cell contribution. Because the algorithm with only one template may cause aliasing, an antialiasing technique exploiting multiple cell templates is proposed. With our method, ray-cast volume rendering can be accelerated considerably. 相似文献
128.
黄正纲 《计算机与数字工程》2012,40(7):31-32,107
目前,地基增强系统(Ground-Based Augment System,GBAS)中的主要问题是:尽管使用载波平滑降低了伪距噪,利用差分技术消除了用户和基准站间的大部分共同误差,从而减少了差分改正值中的误差。但是电离层时间梯度和空间梯度于这两个过程中产生了额外的误差,阻碍了差分改正值质量的进一步提高。基于对电离层时间和空间梯度引起的额外误差的分析,并考虑平滑伪距噪声,文章提出了一种新的Hatch滤波方法,该滤波器的时间常数是随卫星仰角、电离层时间和空间梯度以及用户与参考站之间的距离而实时变化的。该方法降低了差分改正值误差,提高了定位精度。并且通过差分定位仿真并对比传统的单频Hatch滤波方法,发现使用该方法后,减小了差分校正值的误差。 相似文献
129.
130.
庞玲 《计算机与数字工程》2012,40(6):82-84,120
深入研究了利于音频数字水印实现空间定位的技术思想,提出了一种在数字音频中嵌入水印信息后,实现对声源的空间定位算法,详细阐述了该算法的设计思想,并分别给出了音频数字水印的嵌入过程和数字水印的提取过程。 相似文献