数据挖掘技术及Web应用

在计算机与信息技术普及的今天,人们的消费需求、行为和习惯都可以化为海量的用户数据。这样的数据挖掘成果,正逐步为公众所分享。     

SWI: A Semantic Web Interactive Gazetteer to support Linked Open Data

Current implementations of gazetteers, geographic directories that associate place names to geographic coordinates, cannot use semantics to answer complex queries (most gazetteers are just thesauri of place names), use domain ontologies for place name disambiguation, make their data sets available in the Semantic Web or support the use of Volunteered Geographic Information (VGI). A new generation of gazetteers has to tackle these problems. In this paper, we present a new architecture for gazetteers that uses VGI and Semantic Web tools, such as ontologies and Linked Open Data to overcome these limitations. We also present a gazetteer, the Semantic Web Interactive Gazetteer (SWI), implemented using this architecture, and show that it can be used to add absent geographic coordinates to biodiversity records. In our tests, we use this gazetteer to correct geographic data from a big sample (around 142,000 occurrence records of Amazonian specimens) from SpeciesLink, a big repository of biodiversity collection records from Brazil. The tests showed that the SWI Gazetteer was able to add geographic coordinates to around 30,000 records, increasing the records with coordinates from 30.29% to 57.5% of the total number of records in the sample (representing an increase of 90%).     

Exploiting Persistence in Build Management

A challenging issue in the construction and maintenance of large application systems is how to determine which components need to be rebuilt after change, when and in which order. Rebuilding is typically recompilation and linking, but may also include update of derivable components such as cross-reference databases and re-creation of library indexes. Type definitions or schema, and data values in a file store, database or persistent store may also need to be rebuilt. The main purpose of this paper is to describe how persistent language technology can be exploited to enhance build management. In particular, the paper describes a method for transactional, incremental linking and the implementation of its support. To help implement this method, and to make it safer and more efficient to carry out rebuild activities in general, we have defined a set of automatically checkable constraints on the software. The build management tool we have implemented, the Builder, derives rebuild dependencies automatically and offers partitioning of dependency graphs—a means to defer or avoid unnecessary rebuilding. The Builder is implemented in a persistent programming language and provides build management for applications written in the language. It exploits features such as strong typing, runtime linguistic reflection, and referential integrity provided by the language processing technology. The Builder operates over both programs and (complex) data, which is in contrast to conventional language-centred tools. © 1997 by John Wiley & Sons, Ltd.     

Data Layout Transformation Exploiting Memory-Level Parallelism in Structured Grid Many-Core Applications

We present automatic data layout transformation as an effective compiler performance optimization for memory-bound structured grid applications. Structured grid applications include stencil codes and other code structures using a dense, regular grid as the primary data structure. Fluid dynamics and heat distribution, which both solve partial differential equations on a discretized representation of space, are representative of many important structured grid applications. Using the information available through variable-length array syntax, standardized in C99 and other modern languages, we enable automatic data layout transformations for structured grid codes with dynamically allocated arrays. We also present how a tool can guide these transformations to statically choose a good layout given a model of the memory system, using a modern GPU as an example. A transformed layout that distributes concurrent memory requests among parallel memory system components provides substantial speedup for structured grid applications by improving their achieved memory-level parallelism. Even with the overhead of more complex address calculations, we observe up to 10.94X speedup over the original layout, and a 1.16X performance gain in the worst case.     

Exploiting client caches to build large Web caches

New demands brought by the continuing growth of the Internet will be met in part by more effective and comprehensive use of caching. This paper proposes to exploit client browser caches in the context of cooperative proxy caching by constructing the client caches within each organization (e.g., corporate networks) as a peer-to-peer (P2P) client cache. Via trace-driven simulations we evaluate the potential performance benefit of cooperative proxy caching with/without exploiting client caches. We show that exploiting client caches in cooperative proxy caching can significantly improve performance, particularly when the size of individual proxy caches is limited compared to the universe of Web objects. We further devise a cooperative hierarchical greedy-dual replacement algorithm (Hier-GD), which not only provides some cache coordination but also utilizes client caches. Through Hier-GD, we explore the design issues of how to exploit client caches in cooperative proxy caching to build large Web caches. We show that Hier-GD is technically practical and can potentially improve the performance of cooperative proxy caching by utilizing client caches.

A Linked Data approach for the discovery of educational ICT tools in the Web of Data

The use of Information and Communication Technologies (ICT) tools to support learning activities is nowadays generalized. Several educational registries provide information about ICT tools in order to help educators in their discovery and selection. These registries are typically isolated and require much effort to keep tool information up to date. To address this issue, this paper explores whether educational tool registries can be federated to other datasets currently available on the Web of Data. In order to answer this question, and following the Linked Data approach, this paper proposes to collect data from third-party sources, align it to a vocabulary understandable by educators and finally publish it to be consumed by educational applications. This way, an incipient educational dataset can be automatically created and easily maintained, since non-educative information is obtained from updated third-party sources. A case study with practitioners has been carried out to evaluate whether the information about ICT tools provided by this dataset is understandable and useful for educators. Evaluation results show that available information on the Web of Data can be used to obtain suitable tools for real educational settings, thus overcoming the sustainability problems of existing ICT tool registries.     

User Intention Modeling in Web Applications Using Data Mining

The problem of inferring a user's intentions in Machine–Human Interaction has been the key research issue for providing personalized experiences and services. In this paper, we propose novel approaches on modeling and inferring user's actions in a computer. Two linguistic features – keyword and concept features – are extracted from the semantic context for intention modeling. Concept features are the conceptual generalization of keywords. Association rule mining is used to find the proper concept of corresponding keyword. A modified Naïve Bayes classifier is used in our intention modeling. Experimental results have shown that our proposed approach achieved 84% average accuracy in predicting user's intention, which is close to the precision (92%) of human prediction.     

Searching and browsing Linked Data with SWSE: The Semantic Web Search Engine

In this paper, we discuss the architecture and implementation of the Semantic Web Search Engine (SWSE). Following traditional search engine architecture, SWSE consists of crawling, data enhancing, indexing and a user interface for search, browsing and retrieval of information; unlike traditional search engines, SWSE operates over RDF Web data – loosely also known as Linked Data – which implies unique challenges for the system design, architecture, algorithms, implementation and user interface. In particular, many challenges exist in adopting Semantic Web technologies for Web data: the unique challenges of the Web – in terms of scale, unreliability, inconsistency and noise – are largely overlooked by the current Semantic Web standards. Herein, we describe the current SWSE system, initially detailing the architecture and later elaborating upon the function, design, implementation and performance of each individual component. In so doing, we also give an insight into how current Semantic Web standards can be tailored, in a best-effort manner, for use on Web data. Throughout, we offer evaluation and complementary argumentation to support our design choices, and also offer discussion on future directions and open research questions. Later, we also provide candid discussion relating to the difficulties currently faced in bringing such a search engine into the mainstream, and lessons learnt from roughly six years working on the Semantic Web Search Engine project.     

New Ways to Build Rich Internet Applications

Ajax has become a popular open approach for developing rich Internet applications. Now, some vendors are releasing their own Ajax-based development platforms, while others have released proprietary platforms not based on Ajax.     

Web应用系统跨多级防火墙访问企业数据资源的解决方案

分析了企业网的结构,针对防火墙在保障网络安全的同时严格限制外部访问的情况,提出了Web应用系统跨越多级防火墙访问企业数据资源的软件架构。以汽车站客运班次查询为例,基于轻量级JavaEE平台开发了采用该架构的应用系统,阐述了该解决方案的具体实现方法和步骤。并进一步分析了应用服务器,给出了提高应用服务器性能的若干方法。最后,对方案进行了评价,指出了该方案易于扩展、便于维护、灵活性高的特点。实践表明,该方案具有较好的推广应用价值。     

Exploiting location information for Web search

Most Web pages contain location information, which are usually neglected by traditional search engines. Queries combining location and textual terms are called as spatial textual Web queries. Based on the fact that traditional search engines pay little attention in the location information in Web pages, in this paper we study a framework to utilize location information for Web search. The proposed framework consists of an offline stage to extract focused locations for crawled Web pages, as well as an online ranking stage to perform location-aware ranking for search results. The focused locations of a Web page refer to the most appropriate locations associated with the Web page. In the offline stage, we extract the focused locations and keywords from Web pages and map each keyword with specific focused locations, which forms a set of <keyword, location> pairs. In the second online query processing stage, we extract keywords from the query, and computer the ranking scores based on location relevance and the location-constrained scores for each querying keyword. The experiments on various real datasets crawled from nj.gov, BBC and New York Time show that the performance of our algorithm on focused location extraction is superior to previous methods and the proposed ranking algorithm has the best performance w.r.t different spatial textual queries.     

Exploiting temporal information in Web search

Time plays important roles in Web search, because most Web pages contain temporal information and a lot of Web queries are time-related. How to integrate temporal information in Web search engines has been a research focus in recent years. However, traditional search engines have little support in processing temporal-textual Web queries. Aiming at solving this problem, in this paper, we concentrate on the extraction of the focused time for Web pages, which refers to the most appropriate time associated with Web pages, and then we used focused time to improve the search efficiency for time-sensitive queries. In particular, three critical issues are deeply studied in this paper. The first issue is to extract implicit temporal expressions from Web pages. The second one is to determine the focused time among all the extracted temporal information, and the last issue is to integrate focused time into a search engine. For the first issue, we propose a new dynamic approach to resolve the implicit temporal expressions in Web pages. For the second issue, we present a score model to determine the focused time for Web pages. Our score model takes into account both the frequency of temporal information in Web pages and the containment relationship among temporal information. For the third issue, we combine the textual similarity and the temporal similarity between queries and documents in the ranking process. To evaluate the effectiveness and efficiency of the proposed approaches, we build a prototype system called Time-Aware Search Engine (TASE). TASE is able to extract both the explicit and implicit temporal expressions for Web pages, and calculate the relevant score between Web pages and each temporal expression, and re-rank search results based on the temporal-textual relevance between Web pages and queries. Finally, we conduct experiments on real data sets. The results show that our approach has high accuracy in resolving implicit temporal expressions and extracting focused time, and has better ranking effectiveness for time-sensitive Web queries than its competitor algorithms.     

Web数据库的JSP开发技术

本文介绍了当前Web数据库开发中一种新颖、易用的JSP解决方案。文中了JSP的实现技术，并讨论了JSP用JDBC实现数据库访问的技术。     

利用WEB SERVICES集成管理信息系统的WEB应用

WEB服务使业务流程支持面向对象和基于组件的应用,可以通过增加一个服务增加一个服务协议来增强现有的模型从而支持WEB服务.服务协议使系统应用和系统接口完全分离.SUN公司的J2EE平台和微软的.NET平台都能很好的建立和支持WEB服务.本文探讨了如何利用两个平台来集成企业信息系统和基于JAVA的WEB应用.     

面向主题的关系—多维数据模型建立与数据集市

基于关系型数据库如何构建多维数据库的关键技术进行了深入研究,采用对星形模式分解成维表的方法,优化数据库结构,大大提高了数据的查询和处理性能,并用多维数据库实现了一个数据集市.     

面向主题的关系—多维数据模型建立与数据集市

基于关系型数据库如何构建多维数据库的关键技术进行了深入研究,采用对星形模式分解成维表的方法,优化数据库结构,大大提高了数据的查询和处理性能,并用多维数据库实现了一个数据集市。