分布式连接全装配RC楼盖动力特性分析

为研究分布式连接全装配RC楼盖(DCPCD)的动力特性,进行了 4个足尺DCPCD试件和一个整浇板试件在两端简支条件下的锤击法试验和数值模拟分析,研究了 DCPCD的板缝构造、连接件锚固方式、边界约束条件和自重等对楼盖竖向动力特性的影响.试验结果表明:与整浇板相比DCPCD横板向刚度较小,自振频率较低,板缝构造是影响楼盖刚度和振动特性的主要因素;连接件数量越多,楼盖的刚度和自振频率越高;板缝数量越多,楼盖的刚度和自振频率越低.所提出的有限元模拟方法可以准确模拟DCPCD的动力特性;连接件锚固强度越高,楼盖的刚度和自振频率越高;两端嵌固约束下的楼盖基频比两端简支约束下提高了 70％;随着楼盖自重的增加,自振频率显著降低.研究结果可为四边约束下楼盖的竖向振动特性与人致激励响应研究提供参考和依据.     

Adaptive fuzzy control for nontriangular form systems with time-varying full-state constraints

This article investigates an adaptive fuzzy tracking control problem for a class of nontriangular form systems with asymmetric time-varying full state constraints. Unknown functions are approximated by the fuzzy logic systems. A domination approach is employed to tackle the nontriangular form structure. Time-varying asymmetric barrier Lyapunov functions (ABLFs) are adopted to ensure full-state constraints satisfaction. Based on the backstepping technique and time-varying ABLFs, an adaptive controller is proposed and guarantees that all the signals in the closed-loop system are ultimately bounded and the time-varying full state constraints are met. Simulation examples are presented to further demonstrate the effectiveness of the proposed approach.     

基于模式间混淆关系自适应构建层次化分类器

为了解决层次化分类器的设计难点——子分类器的层属关系及其内部组成的确定,本文首先定义了模式间混淆关系,用于描述不同模式在判决域中的相互作用;进而提出了基于混淆矩阵度量模式间混淆关系的方法。设计并实现了多模式混淆关系分析机MPCRAM,将有师指派和无师自组两种常用的模式重组方法有机结合,遵循Fisher准则,自适应地产生层次化分类器结构。大量综合测试证实了该方法有效、实用,可显著提高分类器的识别性能和稳健性。     

地下输水管网的腐蚀调查

介绍了中国石油天然气股份有限公司大庆石化分公司地下输水管网的腐蚀现状与调查分析情况,提出了对地下输水管网实施以深井阳极地床外加电流阴极保护为主、局部欠保护区辅以镁合金牺牲阳极的阴极保护方案。经分析,采取上述防护措施后,每年可产生2488万元的经济效益。     

甲磺酸铜催化合成草酸二异戊酯

制备了甲磺酸铜催化剂,对其结构进行了IR和热重分析,并用于催化草酸和异戊醇的酯化反应。结果表明,甲磺酸铜具有催化活性高、稳定,易分离,重复使用性能优良,对环境友好的特点。最佳酯化工艺条件为:n(异戊醇):n(草酸)=2．8:1,w(甲磺酸铜)=0．3％,以过量的异戊醇为带水剂,回流反应2．0 h,酯化率可达到96．8％。     

焊膏印刷工艺参数的选择与优化

表面贴装工艺流程的关键工序之一就是焊膏印刷,其工艺控制的好坏直接影响着装配的线路板的质量。通过对印刷工艺参数的分析,利用试验设计的方法来找出关键工艺参数,并加以优化设定,从而为控制工序参数奠定基础。     

结合RDF实现对XML文档的RBAC

文章提出了一种面向XML文档的基于XMLschema并结合RDF的访问控制模型,它实现了对XML文档的细粒度的安全访问控制,同时提供了对XML文档中associationsecurityobject的安全访问控制。     

Quantitative pharmacophore models with inductive logic programming

Three-dimensional models, or pharmacophores, describing Euclidean constraints on the location on small molecules of functional groups (like hydrophobic groups, hydrogen acceptors and donors, etc.), are often used in drug design to describe the medicinal activity of potential drugs (or ‘ligands’). This medicinal activity is produced by interaction of the functional groups on the ligand with a binding site on a target protein. In identifying structure-activity relations of this kind there are three principal issues: (1) It is often difficult to “align” the ligands in order to identify common structural properties that may be responsible for activity; (2) Ligands in solution can adopt different shapes (or `conformations’) arising from torsional rotations about bonds. The 3-D molecular substructure is typically sought on one or more low-energy conformers; and (3) Pharmacophore models must, ideally, predict medicinal activity on some quantitative scale. It has been shown that the logical representation adopted by Inductive Logic Programming (ILP) naturally resolves many of the difficulties associated with the alignment and multi-conformation issues. However, the predictions of models constructed by ILP have hitherto only been nominal, predicting medicinal activity to be present or absent. In this paper, we investigate the construction of two kinds of quantitative pharmacophoric models with ILP: (a) Models that predict the probability that a ligand is “active”; and (b) Models that predict the actual medicinal activity of a ligand. Quantitative predictions are obtained by the utilising the following statistical procedures as background knowledge: logistic regression and naive Bayes, for probability prediction; linear and kernel regression, for activity prediction. The multi-conformation issue and, more generally, the relational representation used by ILP results in some special difficulties in the use of any statistical procedure. We present the principal issues and some solutions. Specifically, using data on the inhibition of the protease Thermolysin, we demonstrate that it is possible for an ILP program to construct good quantitative structure-activity models. We also comment on the relationship of this work to other recent developments in statistical relational learning. Editors: Tamás Horváth and Akihiro Yamamoto     

Accurate estimation of capacities and cross-traffic of all links in a path using ICMP timestamps

The estimation of the link capacity and its available bandwidth in an end-to-end path is crucial for network management, admission control and flow control for adaptive applications. This paper introduces an estimation mechanism able to accurately estimate the available bandwidth of all links in an end-to-end path, through its capacity and cross-traffic estimation. The estimation procedures resort to the dispersions of packet pairs and trains using the concepts of ICMP Timestamp and Traceroute that, efficiently used together, enable the measurement of the dispersions in all links in the path. These mechanisms were evaluated through simulation experiments, where we analyzed the influence of the several network parameters on each estimation mechanism. The results show that these estimation methods are able to accurately estimate both the capacity and the cross-traffic of all links in a path with moderate length and with low overhead.     

变换域数字水印处理技术

数字水印是信息安全领域的一项新技术,给出了相对明确的定义。着重分析了变换域数字水印系统的特征及常见攻击,给出了一些相应的对策。最后指出变换域水印的重要问题,即频率的选择问题。