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91.
92.
This paper presents a multiobjective hybrid metaheuristic approach for an intelligent spatial zoning model in order to draw territory line for geographical or spatial zone for the purpose of space control. The model employs a Geographic Information System (GIS) and uses multiobjective combinatorial optimization techniques as its components. The proposed hybrid metaheuristic consists of the symbiosis between tabu search and scatter search method and it is used heuristically to generate non-dominated alternatives. The approach works with a set of current solution, which through manipulation of weights are optimized towards the non-dominated frontier while at the same time, seek to disperse over the frontier by a strategic oscillation concept. The general procedure and its algorithms are given as well as its implementation in the GIS environment. The computation has resulted in tremendous improvements in spatial zoning. 相似文献
93.
求线性规划初始可行基的新方法 总被引:9,自引:3,他引:6
本文提出一个求线性规划初始可行基的新算法,该算法不仅避免了人工变量,而且理论分析及初步的数值实验结果表明其效率更高。 相似文献
94.
Songxin Tan Ram M. Narayanan Sunil K. Shetty 《International Journal of Infrared and Millimeter Waves》2005,26(8):1175-1194
There is growing interest in the use of lidar for remote sensing of vegetation owing to the emergence of reliable and rugged lasers and highly sensitive detectors. Lidar remote sensing has a distinct advantage over conventional techniques in vegetation remote sensing due to its capability for three-dimensional characterization of vegetative targets. The Multiwavelength Airborne Polarimetric Lidar (MAPL) system was developed primarily for vegetation remote sensing applications from an airborne platform of up to 1,000 -m altitude. The lidar system has full waveform capture and polarimetric measurement capability at two wavelengths in the near-infrared (1064 nm) and the green (532 nm) spectral regions. This study presents preliminary ground-based lidar reflectance measurements on a variety of deciduous and coniferous trees under fully foliated conditions with a view towards tree species discrimination. Variations in the reflectance characteristics of selected deciduous trees under unfoliated and fully foliated conditions were also investigated. Our study reveals distinct differences in the reflectance characteristics of various trees. 相似文献
95.
J.J. Pan Xiangdong Qiu Kejian Guan Liang Dong FengQing Zhou Wei Wang Mingjie Zhang James Guo Jun Yang Chunmeng Wu 《光学学报》2003,23(Z1)
A low cost, coolerless 980nm diode pumped, gain flattened L band EDFA with fast transient control, high pump efficiency and gain clamping effect was realized by using FBGs as C band seed generators. 相似文献
96.
用PowerPoint制作出的幻灯片简洁明快、条理清晰,而且PowerPoint简单易用,非常适合教师上课使用,成为教师制作多媒体课件的工具之一(在我校大部分教师采用PowerPoint制作多媒体课件).在制作多媒体课件过程中,结合适当的媒体技术(动画、声音、文字)不仅能提高课件的直观生动性,激发学生学习兴趣,同时有助于学生对课堂知识的当堂消化和理解,加深记忆.通过我校开展多媒体教学多年的实践发现:对医科学生的基础课、专业基础课和专业课教学中广泛涉及的机能性、原理性的知识适当采用动画其教学效果是传统教学方法无法比拟的.在众多的动画媒体中(avi、mov、mpg、swf、gif、ram等),Flash动画(swf文件)以其作品容量小(单个swf文件通常不到100 K)、质量高和丰富的交互性,特别是近年推出的Flash5同时能结合视频和音频,成为目前最为流行的二维动画.不仅为网页制作增添了活力,同时也为多媒体制作提供了有效的手段,既精巧又实用,素有"闪客"、"动画精灵"之美誉,越来越受到人们的青睐.如果要把Flash制作好的动画插入到PowerPoint制作的课件中,将会使PowerPoint单调的动画增色不少,使课件更具魅力.为此,我校专门开展了一系列Flash动画制作讲座,广大教师都能结合本专业制作Flash动画.如何将Flash动画加入到PowerPoint中,不少教师都是直接通过"超级连接"导入Flash课件,放映时总会出现讨厌的警告信息和警告声音提示,点击确定后打开Flash课件,有时打开的Flash课件窗口还要重新调整,使用十分不便.如何才能更恰当地引入Flash动画呢?不少杂志刊物和网上发表过类似文章,但大都比较复杂,而且在使用中特别是在PowerPoint中放映Flash动画偶尔会出现这样和那样的问题,这也是我们教学工作中经常遇到的问题,具有一定的普遍性.经过与教师们的众多交流和笔者平时反复摸索,找到了较为简便有效的方法,写出来与大家分享. 相似文献
97.
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99.
Qingbiao Yang Zhenyu Li Youliang Hong Yiyang Zhao Shilun Qiu Ce Wang Yen Wei 《Journal of Polymer Science.Polymer Physics》2004,42(20):3721-3726
Although there have been many reports on the preparation and applications of various polymer nanofibers with the electrospinning technique, the understanding of synthetic parameters in electrospinning remains limited. In this article, we investigate experimentally the influence of solvents on the morphology of the poly(vinyl pyrrolidone) (PVP) micro/nanofibers prepared by electrospinning PVP solution in different solvents, including ethanol, dichloromethane (MC) and N,N‐dimethylformamide (DMF). Using 4 wt % PVP solutions, the PVP fibers prepared from MC and DMF solvents had a shape like a bead‐on‐a‐string. In contrast, smooth PVP nanofibers were obtained with ethanol as a solvent although the size distribution of the fibers was somewhat broadened. In an effort to prepare PVP nanofibers with small diameters and narrow size distributions, we developed a strategy of using mixed solvents. The experimental results showed that when the ratio of DMF to ethanol was 50:50 (w/w), regular cylindrical PVP nanofibers with a diameter of 20 nm were successfully prepared. The formation of these thinnest nanofibers could be attributed to the combined effects of ethanol and DMF solvents that optimize the solution viscosity and charge density of the polymer jet. In addition, an interesting helical‐shaped fiber was obtained from 20 wt % PVP solution in a 50:50 (w/w) mixed ethanol/DMF solvent. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3721–3726, 2004 相似文献
100.
Shu‐Ling Huang Wei‐Kuo Chin W. P. Yang 《Journal of Polymer Science.Polymer Physics》2004,42(18):3476-3486
The tetramethoxysilane (TMOS)/2‐hydroxylethyl methacrylate (HEMA) hybrid gels were synthesized with acid and base catalysts, via the in situ polymerization of HEMA, with and without the cosolvent methanol. With methanol in the TMOS/HEMA sol, the enhanced esterification and depolymerization reactions of the silanols resulted in a slower growth of silica particles. The silica particles that were synthesized with an acid catalyst were less than 40 nm. The thermal resistance of the poly(2‐hydroxyethyl methacrylate) (PHEMA) chains was enhanced by the addition of colloidal silica. The Fourier transform infrared characterizations and the exothermal peaks on the differential scanning calorimetry traces of these hybrid gels indicated chemical hybridization occurring as a result of condensation of the colloid silica and PHEMA at higher temperatures. Hence, the residual weight content of the hybrid gel after its synthesis with the base catalyst was even higher than the content of TMOS in the hybrid sol. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3476–3486, 2004 相似文献