利用数据仓库技术实现网络流量数据分析

阐述了利用数据仓库的聚合技术，通过设计不同粒度的分级表，实现了对网络流量的海量数据的高效处理．给出了流量分析数据库的设计思想及结构描述，讨论了数据聚合过程．通过采用梯形式的聚合方式，在保证有用信息粒度的基础上，可以大大减少数据量和存储空间，提高查询效率．     

电厂远程专家分析平台的建立

提出了建立电厂远程专家分析平台的整体方案．合理构建了电厂远程实时运行数据库平台，基于此数据库平台，进行专业应用软件的开发．介绍了远程实时监视、远程经济性分析、远程仿真、远程故障诊断等专业软件的开发思路.     

钢-混凝土梁试件的温度分布与温度荷载分析

采用控制容积法来建立钢-混凝土混合梁试件(以下简称“钢-混凝土试件”)温度分布的离散化方程。对钢-混凝土试件在夏季太阳辐射和外气温度变化时的内部温度变化过程进行了数值计算，得到了温度变化规律和分布情况：随着气温和太阳辐射的不断变化，钢-混凝土试件内各点的温度变化趋势近似于余弦曲线，内部温度分布与其所处方位、表面朝向以及太阳辐射强度有很大的关系。指出对青藏线上铁路桥梁结构的温度荷载将产生不利影响问题应予以高度重视。     

纤维对PEI改性环氧树脂单向复合材料形态的影响

人们改善环氧树脂基复合材料的脆性通常只改善环氧树脂基体和增强纤维间的界面，提高环氧树脂韧性的另一种常用方法是添加初始相容性良好的热塑性树脂如聚醚酰亚胺，在某一转化率（取决于体系的组成和反应温度）时体系发生相转变，体系最终的形态由相转变速率和环氧树脂反应速度所控制。本文作者研究了两种增强纤维（玻璃纤维和碳纤维）对不同环氧树脂／聚醚酰亚爱体系形态形成的影响，结果发现体系中纤维的存在不会影响基体相分离过程，但会改变体系的最终形态；形态的变化与纤维的品种关系不大；基体中不同组分的粘度是影响复合材料形态形成的关键因素。     

IEEE 802.1x 认证技术的原理和应用

介绍了IEEE802．1x协议的起源、体系结构、技术特点等，指出了需要认证的端口有受控和非受控两种状态，没有通过认证前，只有EAP报文可以通过端口到达认证服务器，认证通过后，其他数据报文才可以通过。     

一种基于聚类的粗糙集连续属性的离散化算法

粗糙集理论是一种新的处理不精确、不完全与不相容知识的数学工具。粗糙集理论只能对离散属性进行处理，而不能处理连续属性。中针对这一缺陷，利用连续数值属性有序性的性质和统计方差理论，提出了一种基于聚类的连续属性离散化算法。运用典型数据将本算法与现有方法进行了比较分析，得到了满意的结果。     

Splitting an Ordering into a Partition to Minimize Diameter

k consisting of k clusters, with k > 2. Bottom-up agglomerative approaches are also commonly used to construct partitions, and we discuss these in terms of worst-case performance for metric data sets. Our main contribution derives from a new restricted partition formulation that requires each cluster to be an interval of a given ordering of the objects being clustered. Dynamic programming can optimally split such an ordering into a partition P^k for a large class of objectives that includes min-diameter. We explore a variety of ordering heuristics and show that our algorithm, when combined with an appropriate ordering heuristic, outperforms traditional algorithms on both random and non-random data sets.     

Differential effects of the serotonin receptors on cultured rat cerebral cortical neurons

Effects of serotonin (5-HT) on cerebral cortical neurons were examined by patch clamp techniques. 5-HT produced a variety of responses such as outward (19/73 patches/neurons), slow inward (15/73 patches/neurons), fast inward (8/73 patches/neurons), and mixed currents (initially fast inward deflection followed by an outward response: 2/73 patches/neurons), with a latency of 12 sec, 15 sec, 0 sec, and 0 sec respectively, at a holding potential of −60 mV in whole-cell patches. The fast inward currents were again evoked by a selective 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide hydrochloride (CPBG). In the cell-attached patch clamp configuration, 5-HT inside the patch pipette elicited single channel currents with slope conductances of 42 pS and 132 pS (4/42 patches/neurons). CPBG inside the patch pipette evoked inward single channel currents with a lower slope conductance of 41 pS (3/23 patches/neurons). In contrast, application of 5-HT or a 5-HT₂ receptor agonist, α-methyl-5-hydroxytryptamine-maleate, outside the patch pipette induced outward single channel currents with a major slope conductance of 140 pS (8/30 patches/neurons) or 135 pS (6/20 patches/neurons), respectively. These results indicate that the outward and fast inward currents may be mediated respectively by the 5-HT₂ receptor, which is coupled to a G-protein, and by the 5-HT₃ receptor, which contains the non-selective cation channel, and that the mixed type may be caused by both the 5-HT₂ and 5-HT₃ receptors. Received 27 September 1996; received after revision 4 November 1996; accepted 7 November 1996