A distributed dynamic clustering algorithm for wireless sensor networks

This paper proposes a distributed dynamic k-medoid clustering algorithm for wireless sensor networks (WSNs), DDKCAWSN. Different from node-clustering algorithms and protocols for WSNs, the algorithm focuses on clustering data in the network. By sending the sink clustered data instead of practical ones, the algorithm can greatly reduce the size and the time of data communication, and further save the energy of the nodes in the network and prolong the system lifetime. Moreover, the algorithm improves the accuracy of the clustered data dynamically by updating the clusters periodically such as each day. Simulation results demonstrate the effectiveness of our approach for different metrics. Biography: WANG Leichun (1974–), male, Ph.D. candidate, research direction: wireless communication.     

An ontology reasoning architecture for data mining knowledge management

In order to realize the intelligent management of data mining （DM） domain knowledge, this paper presents an architecture for DM knowledge management based on ontology. Using ontology database, this architecture can realize intelligent knowledge retrieval and automatic accomplishment of DM tasks by means of ontology services. Its key features include：①Describing DM ontology and meta-data using ontology based on Web ontology language （OWL）.② Ontology reasoning function. Based on the existing concepts and relations, the hidden knowledge in ontology can be obtained using the reasoning engine. This paper mainly focuses on the construction of DM ontology and the reasoning of DM ontology based on OWL DL（s）.     

Dynamic replication strategies in data grid

Dynamic data replication is a technique used in data grid environments that helps to reduce access latency and network bandwidth utilization. Replication also increases data availability thereby enhancing system reliability. In this paper we discuss the issues with single-location strategies in large-scale data integration applications, and examine potential multiple-location schemes. Dynamic multiple-location replication is NP-complete in nature. We therefore transform the multiple-location problem into several classical mathematical problems with different parameter settings, to which efficient approximation algorithms apply experimental results indicate that unlike single-location strategies our multiple-location schemes are efficient with respect to access latency and bandwidth consumption, especially when the requesters of a data set are distributed over a large scale of locations.     

利用FSO实现文本记录导入ACCESS数据库

在开发WEB应用程序时,将电子文档中成批的数据记录导入至数据库中,可先把电子文档转换为文本文件,然后利用FSO对象模型的TextStream对象,一次性地将存有多条记录的文本信息导入到服务器数据库中,可极大地提高工作效率。     

Seismic tomography of the Moon

We attempted to determine the first three-dimensional P and S wave velocity and Poisson＇s ratio structures of the lunar crust and mantle down to 1000 km depth under the near-side of the Moon by applying seismic tomography to the moonquake arrival-time data recorded by the Apollo seismic network operated during 1969 to 1977. Our results show that significant lateral heterogeneities may exist in the lunar interior. Because there is no plate tectonics in the Moon, the lateral heterogeneities may be produced at the early stage of the Moon formation and evolution, and they have been preserved till today. There seems to be a correlation between the distribution of deep moonquakes and lateral velocity variations in the lunar lower mantle, suggesting that the occurrence of deep moonquakes may be affected by the lunar structural heterogeneity in addition to the tidal stresses. Although this is an experimental work and the result is still preliminary, it indicates that tomographic imaging of the lunar interior is feasible.     

广西钦州配电网电容电流核实测试出现问题的分析及对策

从广西电网发生的几起配电网事故说明测试配电网电容电流的重要性,接着介绍了传统和现在测量配电网电容电流的方法并分析其优缺点,从而证明新方法在电力系统的适用性、可行性,并从钦州供电局测试的数据进行分析,指出现阶段测试配电网电容电流的关键及注意事项.     

有毒可燃气体报警器原理及设计

本文设计了一种对环境中CO浓度进行实时数据采集和处理,并能在浓度超标时报警的电路。该电路通过单片机实现其控制功能。整个报警器电路由四大部分组成：采集模块、放大模块、模数转换模块、单片机。报警器的主要工作流程为：用两类传感器（气体传感器和温度传感器）将所需的模拟信号采集放大后传送给A／D转换器,再经模数转换后将数字信号传送至8051单片机。然后通过单片机内部的数据处理,判断是否需要启动蜂鸣器进行报警。该报警器能广泛应用于居民家庭和企事业单位,从而大大降低由CO所引起的中毒、火灾、爆炸等事故的发生率,保障了人们的生命和财产安全,具有重要的实用价值。     

多元图图形基元和特征基元提取与表示方法

提出一种多维数据多元图图形基元和特征基元提取和表示的方法.首先应用多维数据多元图表示原理实现无结构数据的结构化表示,然后在建立基于多元图图形基元和特征基元表示的一般化表示模型基础上,提取出了表征多元图图形的图形基元和特征基元.为验证该方法的正确性,采用UCI机器学习数据库中的Iris等数据进行了分类实验,不同分类方法实验结果对比证明该方法具有较好的识别效果.     

数据流上基于遗传算法的并行查询优化技术

传统数据库中存储的是相对静态的记录集,这些记录没有预先定义的时间概念,除非时间属性被显示地加上去.虽然这个模型能够较好地表示商业数据库和个人信息存储库,然而它对快速变化的数据流进行在线分析的支持存在很多限制.因此,需要对已有技术进行扩展研究,构建出新的管理系统来管理数据流.数据流的高速性和无限性以及计算机资源的有限性使得提高数据处理速度成为数据流管理系统(DSMS)的关键;本文主要讨论了DSMS的核心技术———查询优化;着重研究了在shared-nothing机群并行系统中,通过并行查询处理技术来提高数据流处理速度的新方法.     

数据仓库和数据挖掘技术在CRM中的应用研究

介绍了数据仓库与数据挖掘的概念,具体对数据仓库与数据挖掘在客户生命周期中发现新客户、挖掘现有客户价值以及保持老客户3个不同阶段的应用进行了分析.