个性化搜索引擎算法研究

搜索引擎是用户利用网络资源不可或缺的工具,但目前搜索引擎的查准率有待提高。对于不同的用户而言,即便是相同的查询词其期望的查询对象可能不同,那么搜索引擎此时的查准率其实就是让搜索引擎具有个性化搜索的特点。个性化搜索引擎的关键是用户兴趣的确定和文档兴趣值的确定,只有把抽象的个性化兴趣量化成数值类的模型,才可以了解用户真正的需求和量化文档与兴趣的相关程度,从而准确地对网页进行筛选并达到个性化排序的功能。     

Structure and distribution of carapace setae in British spider crabs

Carapace setae were examined by SEM in species of spider crabs (Family Majidae). These setae are predominantly hamate (i.e. hooked), to which extraneous materials are attached for the purpose of concealment. They are described for eight species collected around the Isle of Man. In each species setae were sorted to types on the basis of consistent differences in size, shape and fine structure. Diversity ranged from two to six types per species, and this was examined in the context of their masking, or camouflage, habits. Certain setae can be assigned to particular species, so a limited taxonomic usage is indicated: however, further work is required for this to become a comprehensive tool. Distribution of setal types on the carapace is also described, and compared to patterns reported in previous studies.     

福建茶园蜘蛛种类与种群动态的初步研究

对福建茶区茶园蜘蛛开展普查和定期定点调查,初步查明福建省茶园蜘蛛有45种,明确了不同类型茶园天敌蜘蛛,有机生态茶园和综防示范园的害虫治理措施对蜘蛛有显著的保护作用,但综防示范园农药的使用对天敌蜘蛛仍然有一定的影响．此外,茶园耕作措施对台刈蜘蛛种群影响显著．蜘蛛是黑剌粉虱和茶假眼小绿叶蝉的重要天敌,尤其结网蜘蛛对其成虫表现出很高的网捕效果．     

Abundance,species richness and diversity of the orb-weaving spider families Araneidae,Nephilidae and Tetragnathidae in natural habitats in Trinidad,West Indies

This study examined the biodiversity of orb-weaving spiders in natural habitats in Trinidad, a continental island with a northern South American fauna. Forty-six localities were sampled, classified into seven formations (representing vegetation structure) and 16 habitat types (based on plant species composition), using visual search and sweep-netting methods, resulting in a total of 1225 individuals of 57 species. Abundance and species richness were significantly related to formation but not habitat type, while both factors influenced species diversity, evenness and dominance. Gamma (γ) diversity had a larger component of β than α diversity did, indicating that between-habitat differences are a substantial part of regional diversity in orb-weaving spiders in Trinidad.     

Does nutritional status constrain adoption of more costly and less risky foraging behaviour in an Amazonian shelter-building spider?

Individual nutritional status may increase marginal foraging costs and potentially drive animal foraging strategies. Here, we investigated how it might affect foraging strategies of the shelter-building spider Hingstepeira folisecens (Hingston 1932) (Araneidae). This spider can catch prey using two strategies with different relative costs: ‘pulling’ (higher energy expenditure) and ‘pursuing’ (lower energy expenditure). We conducted experiments by offering prey at a fixed distance from the shelter entrance to investigate if spiders with lower nutritional status would exhibit riskier but less costly foraging behaviours more frequently than spiders with better status. The nutritional status did not affect the foraging behaviours adopted by H. folisecens. Additionally, the frequency of both foraging behaviours was similar. Therefore, our results did not provide any evidence that individual nutritional status is a factor driving the selection of foraging behaviours in H. folisecens. We suggest that the malnourished spiders should adopt additional strategies to compensate for the costs of pulling behaviour, especially when prey is far from the shelter. Furthermore, it is possible that other factors, like relative prey size in relation to web size, can help us to understand the threshold that determines when such individuals must adopt one of two possible behaviours.     

虎纹捕鸟蛛（Selenocosimia huwena）粗毒对蟾蜍神经肌肉接头传递的影响

１０－５～１０－４ｇ／ｍｌ虎纹捕鸟蛛粗毒对蟾蜍坐骨神经肌肉标本有阻遏作用，１×１０－４ｇ／ｍｌ粗毒发生阻断的时间为３８ｍｉｎ，但不改变神经干动作电位，不影响肌肉对直接刺激的反应。阻断后肌肉对间接强直刺激仍可发生强直收缩；粗毒对蟾蜍坐骨神经肌肉标本的阻断作用表现为：初期４～５０秒的收缩增强继而转向抑制；粗毒可对抗箭毒的阻断作用；蟾蜍在体坐骨神经肌肉标本可被粗毒阻断，但阻断后可以恢复；粗毒不改变蛙腹直肌对Ａｃｈ的敏感性，粗毒中含有拟胆碱成份。箭毒可以阻止粗毒对蛙腹直肌的拟胆碱效应；该粗毒对蟾蜍坐骨神经肌肉标本的阻遏作用发生在神经肌肉接头，粗毒中含有拟胆碱组份，此组份可能通过后膜去极化阻断神经肌肉接头。     

棉叶螨对久效磷的抗药性研究

对棉叶螨久效磷抗性种群研究表明，棉叶螨对久效磷的抗性可能与ＡｃｈＥ敏感性下降，ＧＳＴ和ＭＦＯ活性上升有关，该种群对常见杀虫，杀螨剂的交互抗性研究结果：久效磷与氧化乐果（１１．２７倍）、水胺硫磷（６．７０倍）等有机磷化合物和三氟氯氰菊酯（１３１倍）及双甲脒（５．７５倍）都有交互抗性，而与其他测定药剂间均无交互抗性。     

基于动态多子族群自适应群居蜘蛛优化算法

为了提高群居蜘蛛优化算法(SSO)样本多样性和算法收敛性能,提出了一种基于动态多子族群自适应群居蜘蛛优化算法(DMASSO).根据算法样本多样性和算法进化程度,动态的将蜘蛛种群分成若干个主导子族群和辅助子族群,在不同子族群中分别引入自适应学习因子和高斯扰动因子改进算法个体更新方式,实现提高算法全局寻优能力和保持群体样本多样性.针对具有典型特点的测试函数仿真结果表明,较SSO算法、MSFLA算法等优化算法相比,新算法在收敛速度和收敛精度上均有明显改善.     

基于机器学习的Web文本分类技术及算法

提出了一种基于机器学习的Web文本自动分类的信息检索解决方案。采用层次约束法完成文本自动抓取功能,文本频度与词条频度相结合的文本特征选择算法实现特征提取,并采用特征加权技术进一步提高文本分类性能。该算法不仅实现中文文本的自动分类,有效地提高Web信息检索的精度,而且能大大降低人工二次浏览筛选的工作量,还可用于电子政务和电子商务信息的自动分类。     

基于类蜘蛛仿生煤矿救灾机器人步态研究

基于类蜘蛛仿生多足煤矿救灾机器人是一种具有冗余运动、多支链、时变拓扑运动机构的特种机器人,利用类蜘蛛仿生煤矿救灾机器人模仿了蜘蛛的行走特点,遵循蜘蛛行走时的摆腿顺序,在不同情况下设计不同的摆腿行走顺序,使煤矿救灾机器人的灵活性以及对复杂环境的适应性大为增强,能够快速灵活的进入煤矿巷道中,对巷道中的复杂情况进行及时了解并及时处理.通过对机器人学的研究,能更好的符合仿生学的发展方向和趋势,使步态模仿蜘蛛法达更加合理稳定的效果,进一步提高机器人的行走速度,缩短救援时间,加强救援能力.