排序方式: 共有201条查询结果,搜索用时 140 毫秒
101.
102.
103.
设H,G为有限群,如果H的子群A为H的Abel直因子,则H到G的同态个数是|A|和|G|的最大公因子的倍数。推广了著名的T.Yoshida定理。 相似文献
104.
针对现有蚁群聚类中将带聚类样本放于网格进行聚类的算法存在随机移动而延长聚类时间,及大数据集进行蚁群聚类时收敛速度慢的缺点,在蚁群进行聚类前增加数据预处理.利用两元素越相似属于同一类簇的可能性越大的思想,将样本集中的样本量缩小.研究了通过信息素进行聚类的蚁群聚类算法,使算法中的"蚂蚁"在一定指导下进行聚类,达到缩短时间的目的.最后通过实验验证了所提出算法的有效性和优越性. 相似文献
105.
基于模糊神经网络的地图匹配算法 总被引:1,自引:0,他引:1
提出了基于模糊神经网络的新的地图匹配算法.该算法综合了数字道路信息和GPS/DR定位信息,提取两个重要参数作为输入变量,即定位点到候选路段的投影距离及定位航向与候选路段方位角差.设计出了四层模糊神经网络及改进的收敛学习规则.实验结果表明所提出的算法能很好地匹配车辆行驶路段位置. 相似文献
106.
The density-based clustering algorithm presented is different from the classical Density-Based Spatial Clustering of Applications with Noise (DBSCAN) (Ester et al., 1996), and has the following advantages: first, Greedy algorithm substitutes for R(*)-tree (Bechmann et al., 1990) in DBSCAN to index the clustering space so that the clustering time cost is decreased to great extent and I/O memory load is reduced as well; second, the merging condition to approach to arbitrary-shaped clusters is designed carefully so that a single threshold can distinguish correctly all clusters in a large spatial dataset though some density-skewed clusters live in it. Finally, authors investigate a robotic navigation and test two artificial datasets by the proposed algorithm to verify its effectiveness and efficiency. 相似文献
107.
木醋杆菌1.1812发酵产细菌纤维素的研究 总被引:1,自引:0,他引:1
通过单因素试验和正交试验对木醋杆菌1.1812液体发酵产细菌纤维素的培养基和培养条件进行优化,得到木醋杆菌1.1812发酵产细菌纤维素的适宜培养基和条件是:蔗糖5%,蛋白胨1.5%,柠檬酸0.2%,Na2HPO4.12H2O 0.2%,KH2PO40.2%,MgSO4.7H2O 0.03%,乙醇1%,pH值6.8,温度28℃,培养周期6 d。细菌纤维素产量干重为2 g/L。发酵完毕后过滤收集粗纤维,再用4%NaOH溶液冲洗,去离子水和0.5%乙酸反复冲洗,即获细菌纤维素。通过Sephadex G-150柱层析对细菌纤维素进行组成分析,发现木醋杆菌1.1812发酵所得的纤维素成分较为单一。 相似文献
108.
植物乙醇提取物对荔枝蒂蛀虫成虫产卵的影响 总被引:7,自引:0,他引:7
本文应用干扰作用控制指数 (IIPC)评价了 2 4种植物异源植物次生物质对荔枝蒂蛀虫成虫产卵的影响 ,结果表明 :在供试的 2 4种植物乙醇提取物中 ,对荔枝蒂蛀虫成虫产卵干扰作用效果较好的有非洲山毛豆Tephrosia vogelli、飞机草 Eupatorium odoratum、大叶桉 Eucalyptus robusta的乙醇提取物 ,其 IIPC值分别为0 .10 94、0 .112 2、0 .12 74 ,即它们对荔枝蒂蛀虫成虫产卵的驱避作用效果在 80 %- 90 %之间。 相似文献
109.
综合考虑影响地空导弹团战斗力的多方面因素,基于AHP方法建立了地空导弹团战斗力模型,以定性和定量相结合的方式来评估地空导弹团战斗力,最后以具体算例证明模型可行。 相似文献
110.
Watermarking system is a complex system requiring both expertise and specialized techniques with security concerns.Thus to relieve the multimedia manufacturers of the complexities of designing complicated watermarking systems, this paper presents a new watermarking model in which watermarking is provided as a kind of service by the specialized watermarking companies. In order to make this service model work, a simple permutation scheme to hide the true contents is proposed. The paper also proves the security of the scheme against the attacks from the watermarking companies. Finally, the effectiveness of the scheme is demonstrated through experiments. 相似文献