法向约束的多幅点云数据融合算法

针对光学测量中多幅点云的数据融合,提出了一种基于法向约束的多幅点云融合算法.该算法首先对多幅点云法向滤波,通过2幅点云的双向查找来寻找种子点,在点的法向方向寻找2幅点云中对应的k邻域,计算邻域点的加权和,而融合点是种子点沿其法向移动的结果.与平均聚类法相比,该方法获得的模型表面更加光顺,特征更明显,点的分布也更均匀,对于包含粗大匹配误差的多幅点云模型的融合具有较好的效果.     

利用变换法计算颗粒动态散射光分形维数

颗粒的动态散射光具有分形特征,可以利用分形维数进行描述.本文分析了变换法在计算颗粒动态散射光分形维数中的应用,利用该法计算了不同温度下粒径为60nm,90nm,200nm,300nm,450nm的聚苯乙烯标准颗粒动态散射光的分形维数,并与盒维数法进行了比较.     

昆虫飞行高升力的一种新解释——柔性楔形效应

以探索仿生扑翼飞行机器人研制为目的,在研究"柔性楔形效应"的基础上,将昆翅视为柔性翅,提出用"柔性楔形效应"解释昆虫飞行高升力的观点.指出了用"柔性楔形效应"解释昆虫飞行高升力的仿生学意义.根据该观点,翅翼在自适应变形状态下施以简单的节律运动将是未来仿生扑翼飞行机器人翅翼驱动方式的发展趋势.仿生运动的模拟越简单越容易稳定地实现,实验小组已设计制作了仿生扑翼飞行机器人样机,并成功进行了多次室外放飞.     

筏板和独立柱基的沉降协调问题探索

对于有裙房的高层建筑,考虑到裙房和主楼之间楼层及荷载差异比较大的问题,采用不同的基础型式,为满足使用功能的要求主楼和裙房连为一个整体.文章在介绍筏板基础和独立柱基设计的同时主要讨论其引起的沉降变形协调问题的解决方法,为同类工程的设计提供参考.     

WA-IDS： A Distributed Intrusion Detection System Based on Data Mining

Aiming at the shortcomings in intrusion detection systems (IDSs) used in commercial and research fields, we propose the MAIDS system, a distributed intrusion detection system based on data mining. In this model, misuse intrusion detection system (MIDS) and anomaly intrusion detcction system (AIDS) are combined. Data mining is applicd to raise detection performance, and distributed mechanism is employed to increase the scalability and efficiency. Host- and network based mining algorithms employ an improved Bayesian decision theorem that suits for real security environment to minimize the risks incurred by false decisions. We describe the overall architeeture of thc MA-IDS system, and discusss pecific design and implementation issue.     

An experimental study on variation of thermal fields during the deformation of a compressive en echelon fault set

The temperature variations during deformation of a compressive en echelon fault set in a rock sample were measured by a surface measurement system with multi-point platinum resistance thermometers and an infrared thermal image system. The measurements obtained by the two systems were in agreement with each other, indicating a relationship between temporal-spatial variations of the thermal field and changes of stress and strain. At varied structural positions of the rock sample, the rising of the temperature was different, implying distinct stress distributions at these positions. In the experiment, the deformation process of the sample included three stages: elastic deformation, stick-slip, and rupture. Correspondingly, the variation process of temperature had also three stages, each of which had its own temperature rising profile. And the thermal radiation field showed a similar process. These phenomena mean that the dominant mechanisms of temperature rising in all stages of deformation are different. Experimental results provide a physical basis for the study of current fault activities by using data of satellite infrared images.     

对高校图书馆参与校园文化建设的探讨

阐述了校园文化与高校图书馆的关系,指出了图书馆参与校园文化建设的途径,提出了图书馆参与校园文化建设的建议。     

Doubling Fock空间之间的正Toeplitz算子

设F~p(φ)为复平面C上的加权Fock空间,其中φ为次调和函数,ΔφdA为doubling测度.本文利用均值函数与t-Berezin变换刻画了F~p(φ)(0p∞)与F~∞(φ)之间具有正测度符号的Toeplitz算子T_μ的有界性和紧性,拓展了已有结果.     

重载货车挂档下坡速度变化特征仿真

为提高长大下坡道路大型车辆行车安全,建立了重载货车整车模型和道路模型,分析了载重量、挂档档位、路面坡度与挂档车速之间的关联和影响,探讨了挂档车速的波动特性及挂档机理,得到了不同坡度各档位挂档车速变化范围,提出了在挂档决策基础上结合驾驶人操纵行为特征谱的新型仿真模式。仿真结果表明:在挂档决策基础上结合驾驶人操纵行为特征谱分析长大下坡车辆行驶安全更具可靠性,从而为驾驶人挂档决策、道路行驶安全研究提供依据。     

压裂液侵入对页岩储层导流能力伤害

大规模水力分段压裂是页岩气等非常规资源高效开发的关键技术。页岩气井返排率一般较低,大量的压裂液长期滞留地层对储层岩石、支撑剂强度等造成一定的伤害,影响页岩储层压裂改造长期效果。针对该问题,通过室内试验模拟研究现场压裂前后气测导流的变化规律,对压裂液伤害程度进行表征。结果表明:压裂液侵入降低了支撑剂、页岩岩石强度,导致支撑剂破碎率、岩石嵌入程度加剧,导流能力伤害达到60%以上;使用大粒径支撑剂、较高铺砂浓度,优选破胶性能好、低残渣、防膨性强的压裂液,能有效提高导流能力,降低压裂液伤害程度。研究结果对页岩地层压裂设计,降低压裂液伤害提高产量提供参考。