Double-layered schema integration of heterogeneous XML sources

Schema integration aims to create a mediated schema as a unified representation of existing heterogeneous sources sharing a common application domain. These sources have been increasingly written in XML due to its versatility and expressive power. Unfortunately, these sources often use different elements and structures to express the same concepts and relations, thus causing substantial semantic and structural conflicts. Such a challenge impedes the creation of high-quality mediated schemas and has not been adequately addressed by existing integration methods. In this paper, we propose a novel method, named XINTOR, for automating the integration of heterogeneous schemas. Given a set of XML sources and a set of correspondences between the source schemas, our method aims to create a complete and minimal mediated schema: it completely captures all of the concepts and relations in the sources without duplication, provided that the concepts do not overlap. Our contributions are fourfold. First, we resolve structural conflicts inherent in the source schemas. Second, we introduce a new statistics-based measure, called path cohesion, for selecting concepts and relations to be a part of the mediated schema. The path cohesion is statistically computed based on multiple path quality dimensions such as average path length and path frequency. Third, we resolve semantic conflicts by augmenting the semantics of similar concepts with context-dependent information. Finally, we propose a novel double-layered mediated schema to retain a wider range of concepts and relations than existing mediated schemas, which are at best either complete or minimal, but not both. Performed on both real and synthetic datasets, our experimental results show that XINTOR outperforms existing methods with respect to (i) the mediated-schema quality using precision, recall, F-measure, and schema minimality; and (ii) the execution performance based on execution time and scale-up performance.     

基于布尔矩阵的Deep Web复杂模式匹配

在正负关联规则中引入布尔矩阵的概念,在双重相关性挖掘算法的基础上提出一种Deep Web复杂模式匹配算法。将查询接口模式中的属性项转化成布尔矩阵,通过对矩阵进行正关联规则运算挖掘组属性,对矩阵进行负关联规则运算挖掘同义属性。实验结果表明该算法的执行效率较高。     

一种基于文档模式的GML压缩方法

GML已成为地理空间数据编码的事实标准.GML文档一般体积庞大,存储和传输时占用巨额资源.提出了一种基于文档模式的有效GML压缩方法,通过用文档推导出的模式验证文档本身,对树自动机的状态转换路径进行比特编码,对坐标数据增量编码,实现GML文档压缩.对真实GML文档的压缩实验表明,所提出方法的压缩率优于通用文本压缩器(gzip和PPMD)、主要高性能XML压缩器(XMill,XMLPPM和XWRT)以及现有GML压缩器GPress.     

A semi-automatic strategy for achieving learning content and practice repurposing

The development of instructional content using Information Technologies is an expensive, time-consuming and complex process that requires new methodologies. It was in this context that the concept of Learning Objects (LOs) was proposed in order to promote reuse. However, this goal is not yet fully attained and new contributions to increase reuse are still welcome. Besides, if content is conveyed in LOs that are easier to reuse, they must be combined and sequenced in order to build more elaborated and complex content. This paper presents a strategy to deal with these problems based on the definition of small LOs here called Component Objects (COs). These COs are structured and combined according to a conceptual metamodel, which is the basis for the definition of conceptual schemas representing the existing material, including not only content but also practice. This strategy for searching, extracting, and sequencing COs, supports a teacher to better control the implementation of complex content, reducing errors in the authoring process. This approach includes a specification language and an algorithm for semi-automatic sequencing learning content and practice. Finally, a case study that shows the proposed approach and some results of using the algorithm are presented.     

METAPHOR RECOGNITION: CHMETA, A PATTERN-BASED SYSTEM

Metaphor recognition presents a computational challenge, in part due to metaphoric deviation from literal thinking, and also because of a metaphor's various linguistic expressions. This article forwards a new computational method, an integrated treatment of metaphor recognition from the computational perspective, which recent related studies have not entirely addressed. The authors differentiate metaphor recognition from complex metaphor inference and interpretation employing psychological clues. To accomplish this, we have developed a formalized system of metaphorical expression in metaphor role dependency schema, which specifically defines, classifies, and quantifies metaphorical anomalies, building a computable classification system for metaphors (incorporating 32 major patterns of metaphorical expressions) by providing a strategy to locate potential metaphorical anomalies in a target input sentence through a pattern recognition method and a metaphor components' tagging approach. This metaphor recognition and tagging system is named and implemented as "CHMeta." Experiment results support the validity and efficiency of this metaphor recognition system. Compared with most metaphor computation systems, which work mainly on a few examples, this system classifies major metaphorical expressions from a computational perspective and is able to recognize a variety of different kinds of metaphors, including nested ones. Thus, this is the first integrated work in computable classification, recognition, and tagging of large-scale metaphors in Chinese.     

深层网查询接口的自动集成

深层网数据库的访问方式主要是通过查询接口,所以查询接口是外部访问深层网数据库的门户.为了能够同时访问同一领域多个Web数据库,需要对多个Web数据库的查询接口进行集成.因此,提出基于本体的深层网查询接口集成方法.首先构建领域核心本体,在模式匹配过程中,不断完善核心本体;然后,以本体作为媒介,在不同查询接口模式间建立属性映射关系,发现属性间的语义关联;最后,根据本体概念出现的频数生成集成接口.实验表明提出的深层网查询接口自动集成方法是可行的和高效的.     

网格环境下基于P2P的数据集成方法

针对旧有数据集成方法已不适应网格环境下高动态数据集成的现状,提出基于P2P的数据集成方法,给出一个异构的XML数据源的集成框架。通过在各Peer点直接建立模式映射,利用给出的分解再组成算法,有效地完成对各网格节点上动态XML数据源的集成。     

基于SIPN的PLC通用编程器

针对PLC编程器的缺陷,建立PLC通用编程器抽象模型,采用中间格式代码和配置文件链接生成可下载的PLC程序。利用信号解释Petri网对控制系统模型进行规格并将其转换成中间格式代码。抽象出不同机型PLC系统的特性信息,生成统一模式的XML类型配置文件。根据机型选择,通过PLC通用处理器提取相应配置文件,与中间格式代码链接,重组代码并生成与机型适配的可执行程序。     

基于SCEA的模糊控制器的优化设计研究

有关最优模糊控制器设计的研究已经提出许多年了,也因此而提出了各种各样的模糊建模方法。该文为模糊建模提出了一种新颖的算法――计划协同进化算法(Schema Coevolutionary Algorithm-SCEA),用该算法来设计最优模糊控制器,并将优化后的模糊控制器用于汽车防抱死制动系统(ABS)。理论分析以及仿真试验都验证了该算法的有效性。     

GML模式匹配技术研究

GML是基于XML的空间信息编码标准。GML模式匹配技术作为实现应用模式的集成与共享的关键技术,与GML解析机理和实现技术密切相关。本文详细介绍了关于GML模式匹配的概念;给出了匹配方法的步骤、算法及已所实现的模式匹配详细流程,包括语意与结构相似度判断以及权重的设置;最后,对匹配过程中包含的不确定因素进行了分析与讨论。