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911.
一种基于BTC-PCA的彩色图象压缩方法 总被引:1,自引:0,他引:1
本文提出的彩色图象压缩方法基于BTC(块截断编码)和PCA(主成分分析)的有效结合。先利用PCA方法将图象象素分成二类,简单地实现了矢量量化;然后用BTC方法对分类象素进行简单而高效的编码。实施结果表明此方法简单、易行,效果良好。 相似文献
912.
In this paper we present a nonmonotone trust region method for nonlinear least squares problems with zero-residual and prove its convergence properties. The extensive numerical results are reported which show that the nonmonotone trust region method is generally superior to the usual trust region method. 相似文献
913.
新型的一次性化学离子敏钾、钠测试卡片,是基于离子选择电极(ISE)原理设计制作的一种电化学传感器~[1]。它由测量电池装置、敏感膜、接触衬底(石墨)和盐桥等构件组装而成。采用两点电位测量法。具有一次性使用、简便、快速、精确度高、成本低等优点,对样品不必作预处理,避免了交叉污染,克服了ISE重现性差、固有漂移等缺点,发挥了ISE选择性好、准确度高等优点。根据临床应用和抽样测试结果,钾、钠测试卡片的精密度±SD:钾1.0;钠2.0,C.V%:钾3.0%;钠2.0%;响应时间为30s;漂移:钾0.3mV/min;钠0.5mV/min;回收率为99.5%,均符合临床应用的基本要求。 相似文献
914.
The Lovász Local Lemma is a useful tool in the “probabilistic method” that has found many applications in combinatorics. In this paper, we discuss applications of the Lovász Local Lemma to some combinatorial set systems and arrays, including perfect hash families, separating hash families, ?-free systems, splitting systems, and generalized cover-free families. We obtain improved bounds for some of these set sytems. Also, we compare some of the bounds obtained from the local lemma to those using the basic probabilistic method as well as the well-known “expurgation” method. Finally, we briefly consider a “high probability” variation of the method, wherein a desired object is obtained with high probability in a suitable space. 相似文献
915.
916.
A novel communication technique is proposed, which utilizes a set ofmutually distinguishable optical pat terns instead of convergent facula to transmit information. Then the capacity is increased by exploiting the optical spatial bandwidth resources. At last, we experimentally demonstrate the proposed communication technique based on four 8 × 8 spatial pattern signals by using lenslet array processor. 相似文献
917.
Xiaobo Deng Rong Luo Hualin Chen Bailing Liu Yujun Feng Yuhai Sun 《Colloid and polymer science》2007,285(8):923-930
Composite latex particles of acrylate and polydimethylsiloxane (PDMS) with high PDMS content was prepared by emulsion copolymerization
and characterized by particle size analyzer, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR).
With gemini surfactant as the co-emulsifier in the system, the PDMS content in the system reached 50%, which was far higher
than the other reported values. Through the characterization of the particle size analyzer, the particle size augmented with
the increase of the amount of PDMS, which could be said that the polysiloxane had participated into the reaction and had been
introduced into the colloid particle. The results of FTIR indicated that almost all the monomer had been exhausted in the
reaction because there was no C=C and D4 characteristic peaks in the spectrum. Besides the surface properties also were measured by surface tension analysis, water
absorption, and the static contact angle, it could be found that with the increase of polysiloxane content, the excellent
properties acquired by PDMS were clearly revealed by the findings, such as the decrease of surface tension and water absorption,
and the increase of static contact angle. All the measurements were consistent with the conclusion that the composite latex
particles of polysiloxane and acrylate with high siloxane content had been prepared successfully. 相似文献
918.
919.
920.
一个近-三角剖分嵌入是指一个曲面上的嵌入图使得几乎所有的面都是三角形,至多只有一个可能的例外.文中作者证明了如下结论:如果一个图G 在球面S0(或环面S1)上有近-三角剖分嵌入,那么G在每一个可定向曲面Sk有近-三角剖分嵌入,其中k=h,h+1,\cdots ,\lfloor\frac{\beta(G)}{2}\rfloor$, 而h=0(或1)并且β(G)是图G的Betti数.特别地,G是上可嵌入的. 相似文献