空间点群目标相似度计算   总被引：2，自引：1，他引：1  

刘涛  杜清运  闫浩文 《武汉大学学报(信息科学版)》2011,36(10):1149-1153

顾及到视觉认知的Gestalt原则,提出了一种综合考虑到点群的空间关系、空间分布和几何特征,注重空间点群的整体描述的相似度计算模型。实验结果表明,相似度计算结果与直观认知比较一致。  相似文献   

Abundance of general aerobic heterotrophic bacteria in the Bering Sea and Chukchi Sea and their adaptation to temperature   总被引：3，自引：0，他引：3  

陈皓文  高爱国  孙海青  矫玉田 《极地研究(英文版)》2004,15(1):39-46

1　IntroductionInthedeepseawithawatertemperaturelowerthan5℃andtheseabottom ,theor ganicmattersareoxidizedmainlybytheaerobicbacteria (BenderandHeggie 1 984;Her bert 1 986) ,whichmeansthattheaerobicbacteriainthisenvironmentareratherabun dant.Thearcticseaareaisanareawhereenvironmentispermanentlycold ,butsomere searchresults (Sahmetal.1 998)indicatethattherearedominantbacteria eubacteriainthearcticseawaterandsediment,andtheiradaptationtotemperaturehasnosubstantialdifferenceincomparisonwiththatof…  相似文献   

南极长城站微生物考察          下载免费PDF全文

陈皓文  宋庆云  卢颍 《极地研究》1992,4(4):7-13

198 6- 1 987年中国第三次南极考察中 ,对南极长城站空气、陆上和海滨的微生物作了考察。长城站野外空气中的微生物含量较低 ,海洋性微生物为 1 4 8.7CFU/ m3 ,陆源性微生物为 1 7.9CFU/ m3 ,表明野外空气相当洁净。室内空气微生物数比室外及野外均高得多 ,霉菌的检出率和含量都不高。微生物因人群活动和环境的不同而异。陆上的微生物含量次序是 :冰雪 <湖水 <原土等。海滨的微生物含量相当多 ,>1 0 3 CFU/ cm3 (或 g)。长城站的微生物组成有 1 1属以上 ,包括偶见的芽孢杆菌。温度试验结果表明 ,野外的大部分菌株适于低温生活。没有发现能在≥2 5℃的温度中存活者。低温是控制长城站微生物生态的一个重要因子。在长城站这类环境中 ,低温微生物对物质转化和循环发挥着持久的重要作用  相似文献   

基于方向Voronoi图模型的群组目标空间方向关系计算   总被引：1，自引：0，他引：1  

王中辉  闫浩文 《武汉大学学报(信息科学版)》2013,38(5):584-588

根据群组目标间方向关系的特点,对方向Voronoi图模型进行了扩展,并在其基础上实现了群组目标间方向关系的计算。实验表明,该模型能够在各种复杂情况下,对群组目标间的方向关系进行精确的描述。  相似文献   

地图点群综合的加权Voronoi算法     

闫浩文  王邦松 《武汉大学学报(信息科学版)》2013,(9):1088-1091

提出了一个基于加权Voronoi图的地图点群综合算法。为点群中包含的统计、专题、拓扑和度量信息分别选定量化描述因子,并把这些因子运用到点群综合过程中,来保证对应类型信息的正确传输;点群综合的过程借助于反复构造点群的加权Voronoi图来实现。  相似文献   

超高层建筑风荷载计算中的振型函数   总被引：2，自引：1，他引：1  

徐永林  朱元清  周晶矛  范宜瑶  秦浩文  阮镇基  干劲 《地震地磁观测与研究》2010,31(3):111-114

在我国高层建筑建筑规范中关于风荷载计算中有一振型函数表达式Φ_z=tan(π(Z/H)~(0.7)/4),这一公式在计算风荷载中被广泛采用。作者在对金茂大厦风振位移的观测和研究中,发现该公式与实际观测的结果不符。本研究给出金茂大厦这样的超高层建筑物的实测振型函数表达式:给出与建筑规范不同的风荷载振型函数,供建筑界参考;积累超高层建筑风振振型函数样本,以便在规范中给出符合实际振型函数的表达式,提高风荷载计算精度,设计出既经济又抗强风的超高层建筑。  相似文献   

Effect of a polybrominated diphenyl ether congener (BDE-47) on growth and antioxidative enzymes of two mangrove plant species, Kandelia obovata and Avicennia marina, in South China     

Ying Wang  Haowen Zhu  Nora Fung Yee Tam 《Marine pollution bulletin》2014

The effects of BDE-47 on the growth and antioxidative responses of the seedlings of Kandelia obovata (Ko) and Avicennia marina (Am) were compared in an 8-week hydroponic culture spiked with different levels of BDE-47, 0.1, 1, 5 and 10 mg l⁻¹. The two highest BDE-47 levels significantly suppressed the growth and increased the activities of three antioxidative enzymes, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), of Ko in week 1. However, SOD and POD activities at high levels of BDE-47 became lower than the control in week 8. On the contrary, growth of Am was not affected at all contamination levels, and the activities of three enzymes were enhanced by BDE-47 in weeks 1 and 4, but such stimulatory effect became insignificant in week 8. Avicennia was more tolerant to BDE-47 toxicity than Kandelia, as its antioxidative enzymes could better counter-balance the oxidative stress caused by BDE-47.  相似文献   

A normalization-based watermarking scheme for 2D vector map data     

Haowen Yan  Liming Zhang  Weifang Yang 《Earth Science Informatics》2017,10(4):471-481

Copyright protection of 2-dimensional (2D) vector map data is of great importance in the community of geographic information sciences. However, no blind, imperceptible and robust algorithm has been proposed by far. To fill the gap, this paper puts forwards a normalization-based watermarking algorithm for 2D vector map data: firstly, each coordinate of the original vector map data is normalized, and the watermark is shuffled; then the shuffled watermark is multiply embedded in the normalized vector data. After this, the coordinates of the watermarked data is restored (i.e. anti-normalized) for normal use. Once a suspicious copyright piracy appears, the watermarked data is re-normalized and the watermark can be detected and extracted. Our mathematical proofs and experiments have shown that the scheme owns four features that a good watermarking algorithm should possesses, i.e. usability, invisibility, blindness and robustness: the precision of the watermarked data can be guaranteed (usability); the users cannot perceive the embedded watermark (invisibility); the watermark can be extracted without knowing the original data and the original watermark; and the algorithm can resist a number of attacks such as translation, scaling, vertices reordering, vertex deletion, vertex insertion, vertex modification, cropping, and data format transformation (robustness).  相似文献   

Reading the Past,Informing the Future: Progress and Prospective of the Recent Ocean Drilling Researches on Climate and Ocean Change     

Zhimin Jian  Haowen Dang 《地球科学进展》2017,32(12):1267-1276

Aiming at the current climate status, i.e., drastic rise of atmospheric greenhouse gases and the apparent trend of global warming, the International Ocean Discovery Program (IODP), launched in 2013, proposed four scientific challenges, including the response of global climate to CO₂ rise, the feedback of ice-sheet and sea-level to global warming, the dynamics of the mid- and low-latitude hydro-cycle, and the mechanism of the marine carbon-chemical buffering system. By August 2017, eight IODP expeditions of climate-related themes were implemented, focusing on the Neogene evolution of the monsoon system over Asia-Pacific-Indian and the West Pacific Warm Pool, with specific interests in the variabilities and mechanisms of the Asian Monsoon system on orbital-to millennial-scales, as well as the connections between Asian Monsoon and the uplift/weathering of the Tibetan Plateau on tectonic time scale. The planned IODP expeditions in the forthcoming two years will explore the Southern high-latitude climate histories of West Antarctic ice in the Cenozoic, and Southern Ocean currents and carbon cycle in the Cretaceous-Paleogene. In sum, during the current phase of IODP (2013-2023), our knowledge about the marine climate system would be greatly advanced via deciphering the past changes in tropical processes of Asian Monsoon and West Pacific Warm Pool, as well as in high-latitude factors of the West Antarctic ice. A better scientific background of natural variability would be provided, accordingly, for predicting the future tendency in climate change. In this context, China’s strategic directions include the global monsoon concept, the tropical forcing hypothesis, and in particular the climate effect of the Sunda Shelf.  相似文献   

南设得兰群岛区域的微生物          下载免费PDF全文

陈皓文  宋庆云 《极地研究》1992,4(4):1-1

198 6年 1 2月 - 1 987年 3月对南设得兰群岛海区和麦克斯威尔湾的空气、长城湾远岸表层海水、欺骗岛潮间带表层海水、底质和火山灰的微生物作了考察研究。结果表明 ,两个测区的空气中陆源性微生物的检出率在 90 %以上 ,每立方米空气中一般含几个 CFU。海洋性微生物的检出率在 50 %以上 ,数量较小 ,每立方米空气仅 1个左右的 CFU。麦克斯威尔湾比南设得兰群岛海区的空气微生物数稍高些。测区的空气微生物受岛屿的影响较大。空气微生物数呈现出某种昼夜变化。空气微生物数受气温、相对湿度的影响不大明显。每立方厘米的长城湾远岸表层海水含几百个 CFU的微生物。其数量随水温的逐月降低减少 ,并显示出某种昼夜变化趋势。该湾海水比较洁净。空气中的海洋性微生物与海水中的微生物呈现出某种关系。长城湾海水细菌有1 3属以上。以假单胞菌为常见者。欺骗岛潮间带每立方厘米海水中只有几个 CFU,火山灰中的含菌量达每克数千个 CFU。以上结果基本反映了南设得兰群岛一带空气、海洋和陆上的微生物一般状况 ,并为进一步考察和开发该区域的微生物资源提供了资料  相似文献