XTRANS:一个XML与关系数据相互转换系统

可扩展标记语言XML已逐渐成为了WWW中业务数据的交换标准,利用XML文档作为载体可以在各种异构的业务系统间交换信息,具有灵活、方便、快速的特点。该文提出了一种XML与传统关系数据相互转换的系统框架,XTRANS就是在此基础上实现的一个XML与关系数据的转换系统。系统借助一个映射文件来定制系统的转换细节,能够实现保序的转换。通过扩展映射文件可以使系统满足用户的不同需求。     

Storing user experiences in mixed reality using hypermedia

This paper describes HyperMem, a system to store and replay user experiences in mixed environments. The experience is stored as a set of hypermedia nodes and links, with the information that was displayed along with the video of the real world that was navigated. It uses a generic hypermedia model, implemented as software components, to handle mixed reality environments. This model includes components for storing and replaying experiences and integrating them in the overall set of hypermedia graphs that can be accessed by a given user. The paper presents the goals of the system, the underlying hypermedia model, the application scenarios, and the architecture and tools for replaying and repurposing stored information.     

一个开放可扩展的SDAI实现系统

STEP标准数据存取界面－SDAI为应用程序提供了独立于数据存储的STEP数据访问界面，SDAI允许访问不同的数据存储系统，有不同的实现语言联编方式，如果对每一种实用语言和数据存储系统单独实现SDAI，其工作量将是巨大的，该文选择系数据库作为SDAI数据存储系统，C语言作为实现语言，实现系统独立于不同的关系数据库系统，并且为不同语言的联编提供了一个统一的开发平台，提高了系统的开放性和可扩展性，为STEP在企业信息集成中的应用提供了核心操作，STEP建模语言EXPRESS，关系数据库，SDAI实现语言在模式表示上的不匹配是系统实现要解决的主要问题，该文从数据字典，STEP数据的字储与访问等方面阐明了系统实现时没模式之间的匹配过程。     

Toward intelligent styling for digital museum exhibitions: modularization framework for aesthetic hypermedia presentations

In current Web-based hypermedia environments, constructing and maintaining a large-scale interactive aesthetic hypermedia exhibition is a difficult task. In particular, the shaping of presentation styles requires tedious multimedia composing and is indeed extremely laborious. As our first step toward developing an intelligent styling system for digital museum exhibitions, this paper proposes a fine-grained modularization framework that decomposes the styling of a typical hypermedia presentation into fine-grained style modules (FGSM). A hypermedia document based on a monomodal media handler and a digital museum exhibition management framework have been designed to realize the concept of FGSM. We have implemented a Web-based authoring system that allows content providers to efficiently construct mediacentric, interactive, aesthetic hypermedia Web sites. In the future, relevant optimization and constraint-solving techniques will be exploited to achieve the goal of intelligent styling for digital museum exhibitions .     

The aditi deductive database system

Deductive databases generalize relational databases by providing support for recursive views and non-atomic data. Aditi is a deductive system based on the client-server model; it is inherently multi-user and capable of exploiting parallelism on shared-memory multiprocessors. The back-end uses relational technology for efficiency in the management of disk-based data and uses optimization algorithms especially developed for the bottom-up evaluation of logical queries involving recursion. The front-end interacts with the user in a logical language that has more expressive power than relational query languages. We present the structure of Aditi, discuss its components in some detail, and present performance figures.     

High speed architectures for Leviathan: a binary tree based stream cipher

Connectionless routed networks, built atop high-speed communication medium, require cryptographic algorithms capable of out-of-order keystream generation and high throughput. Binary tree based stream ciphers, of which Leviathan is an example, are capable of meeting both of these requirements. We investigate high-speed architectures for the binary tree traversal and show that the traversal approaches discussed can be extended to m-ary tree of height h. Of the two architectures presented, the pipeline architecture computes keystream at uniform rate and the parallel architecture bounds the worst-case variance in the time period between computations of consecutive output key words, which form the keystream. The design and implementation of Leviathan keystream generator based on the pipeline architecture for binary tree traversal are presented. We show that it is possible to achieve keystream generation rates approaching 1 Gbps with the pipeline architecture. The design was implemented in two parts, the keysetup and the keystream pipeline, targeting commercially available Xilinx XC2V4000 and XC2V3000 FPGAs. The keystream pipeline implementation operated at frequency of 50 MHz and occupied 6864 slices. The results were verified performing the timing simulation.     

基于O-D的XML编码及对信息查询与更新的支持

提出了一种基于区间表示的XML编码方式,设计了相应的关系存储模式,研究了该编码方式对信息查询和信息更新的支持。鉴于XML关系存储下信息更新的困难性,采用基于order-descendan(O-D)的XML编码方式,不仅可以完全支持XPath查询语言的13个查询轴的查询功能,而且通过简单的计算即可有效地支持XML数据的增加和删除,这种简单计算可以在关系存储模式下通过SQL语句方便地实现。     

Supporting Hypermedia Services in the User Interface

This paper presents an architecture for developing hypermedia systems in which hypermedia services are provided primarily through the interface and hypermedia components of an application. The architecture relieves the application component and its developers from the issues associated with hypermedia. It also allows a common hypermedia engine and interface to be used in multiple applications to present a consistent view of a hypermedia model. A prototype of the architecture is presented with examples of the hypermedia facilities which can be provided. The discussion associated with the prototype demonstrates that many of the common features of pure hypermedia systems can be supported. Limitations and future research issues also are discussed.     

JPernLite: extensible transaction services for the WWW

Concurrency control is one of the key problems in design and implementation of collaborative systems such as hypertext/hypermedia systems, CAD/CAM systems, and software development environments. Most existing systems store data in specialized databases with built-in concurrency control policies, usually implemented via locking. It is desirable to construct such collaborative systems on top of the World Wide Web, but most Web servers do not support even conventional transactions, let alone distributed (multi-Website) transactions or flexible concurrency control mechanisms oriented toward team work-such as event notification, shared locks, and fine granularity locks. We present a transaction server that operates independently of Web servers or the collaborative systems, to fill the concurrency control gap. By default, the transaction server enforces the conventional atomic transaction model, where sets of operations are performed in an all-or-nothing fashion and isolated from concurrent users. The server can be tailored dynamically to apply more sophisticated concurrency control policies appropriate for collaboration. The transaction server also supports applications employing information resources other than Web servers, such as legacy databases, CORBA objects, and other hypermedia systems. Our implementation permits a wide range of system architecture styles     

一种多媒体数据库管理系统的体系结构

文中简要介绍了一种基于层次－关系模式的多用户媒体数据库管理系统的客户／服务器体系结构以及多媒体声音图象的存储方式。对用于描述多媒体图象，声音及ＭＩＤＩ音乐的数据类型－Ｍ类型进行了扩充。     

Online adaptive decision trees: pattern classification and function approximation

Recently we have shown that decision trees can be trained in the online adaptive (OADT) mode (Basak, 2004), leading to better generalization score. OADTs were bottlenecked by the fact that they are able to handle only two-class classification tasks with a given structure. In this article, we provide an architecture based on OADT, ExOADT, which can handle multiclass classification tasks and is able to perform function approximation. ExOADT is structurally similar to OADT extended with a regression layer. We also show that ExOADT is capable not only of adapting the local decision hyperplanes in the nonterminal nodes but also has the potential of smoothly changing the structure of the tree depending on the data samples. We provide the learning rules based on steepest gradient descent for the new model ExOADT. Experimentally we demonstrate the effectiveness of ExOADT in the pattern classification and function approximation tasks. Finally, we briefly discuss the relationship of ExOADT with other classification models.     

MUSiCAL: An object-oriented hypermedia data model for the reuse of museum information for computer-aided learning and the World-Wide Web

As museum databases are computerized, a rich and extensive resource that could be reused to create World Wide Web pages and computer-aided learning materials is being created. This reuse can be facilitated using a complex set of views of museum data for many different contexts and applications. This paper presents MUSiCAL, a data model and methodology for the structuring and encoding of all types of museum information to do this. This model supports all museum uses of the information, and the retrieval and manipulation of this material by computer aided learning and World Wide Web authors.In this model, museum information is stored as distinct units called entity-objects, which capture all information relating to an object, person, place or company. Novel hypermedia techniques (called layers and wrappers) are used to create varied abstractions of the entity-objects for different users and uses. Material is stored in a context independent manner, but context sensitive views can be created, allowing units of information to be connected together in more than one contextual view. These structures facilitate the organisation and retrieval of objects and create a varied range of abstractions to help support reuse.     

基于Oracle XML DB的XML存取技术研究

XML近来已成为Web上数据表示与交换的标准,而由此带来的一个亟需解决的问题就是XML数据在关系数据库中如何存储与管理。以Oracle数据库为例,简要介绍了Oracle XML DB技术,并用实例说明如何利用这种技术将XML和关系数据库联系起来,实现对XML文档的存取。     

Broadening the Scope of Hypermedia Principles

Hypermedia systems have been implemented for such a wide range of applications that one must wonder whether their principles should not be included among the building blocks of computer environments themselves. In this paper, we argue that this would indeed be desirable and present a model on which such extension could be based.

After a brief review of hypermedia principles and the terminology used in this paper, we give examples of several computer applications in which hypermedia already are or could advantageously be used. We then suggest that most computer applications would greatly benefit if hypermedia were extended from isolated applications to a system-wide facility and that this could substantially simplify implementation of new hypermedia applications. This claim is then generalized and it is shown that extending hypermedia concepts to the organization of the computer environment itself --- the file system --- and to the user interface would make computer environments more flexible and easier to use.

We then list the main characteristics of such a ‘hyperenvironment’ and conclude the paper with an outline of its implementation model and an example.     

Query processing over object views of relational data

This paper presents an approach to object view management for relational databases. Such a view mechanism makes it possible for users to transparently work with data in a relational database as if it was stored in an object-oriented (OO) database. A query against the object view is translated to one or several queries against the relational database. The results of these queries are then processed to form an answer to the initial query. The approach is not restricted to a ‘pure’ object view mechanism for the relational data, since the object view can also store its own data and methods. Therefore it must be possible to process queries that combine local data residing in the object view with data retrieved from the relational database. We discuss the key issues when object views of relational databases are developed, namely: how to map relational structures to sub-type/supertype hierarchies in the view, how to represent relational database access in OO query plans, how to provide the concept of object identity in the view, how to handle the fact that the extension of types in the view depends on the state of the relational database, and how to process and optimize queries against the object view. The results are based on experiences from a running prototype implementation. Edited by: M.T. ?zsu. Received April 12, 1995 / Accepted April 22, 1996     

支持网络化、协同化的超媒体平台*

在分析超媒体系统的发展趋势和需求的基础上,提出一个支持网络化、协同化的超媒体平台模型,讨论了该系统的体系结构,并介绍了该平台在教育领域中的应用。     

Management of complex immunogenetics information using an enhanced relational model.

Flow cytometry has become a technique of paramount importance in the armamentarium of the scientist in such domains as immunogenetics. In the PENGUIN project, we are currently developing the architecture for an expert database system to facilitate the design of flow-cytometry experiments. This paper describes the core of this architecture--a methodology for managing complex biomedical information in an extended relational framework. More specifically, we exploit a semantic data model to enhance relational databases with structuring and manipulation tools that take more domain information into account and provide the user with an appropriate level of abstraction. We present specific applications of the structural model to database schema management, data retrieval and browsing, and integrity maintenance.     

基于XML Schema的XML存储

文章介绍了一个在关系数据库中,基于XMLSchema的XML存储方案。描述了一个以树模型为模型,XMLSchema为模式的XML数据库的存储系统。首先给出了在关系数据库中存储XMLSchema的方法,在此基础上,又给出了存储XML文档的方法。与通常的XML分解存储方案不同之处在于,在该方案中,XMLSchema被保存到数据库中,未作模式映射,避免了模式映射通常会带来的数据丢失和数据要分散到多个关系表中的问题;对XML文档的存储和查询都是基于XMLSchema的;并且由于所有基于同一个模式的XML文档共享该模式的结构,不必对结构信息进行重复存储,减少了存储空间;最后,由于我们为每一个元素赋予了一个唯一ID值,在进行查询的时候,可以利用该ID值进行定位,具有和XPath表达式相同的作用,但是更为简便。     

HypEs: an architecture for hypermedia-enabled expert systems

Expert systems and hypermedia constitute two important technologies for organizations to create, store, and manage information products. The purpose of our research is to develop an architectural blueprint for the construction of hypermedia-enabled expert systems. We propose an architecture termed HypEs (Hypermedia-enabled Expert System) for the development of media-rich expert systems. The integration of hypermedia technologies and expert systems can provide significant potential benefits by enabling the storage and manipulation of non-textual knowledge, enhancing the effectiveness of both knowledge acquisition from the sources of expertise and knowledge transfer to non-expert users. An experimental analysis that contrasts the hypermedia-enabled and text-restricted expert systems provides results that underscore the usefulness of hypermedia techniques in enhancing the effectiveness of expert systems in practical applications.     

Relational storage and processing of two-dimensional diagrams

We present a relational representation of diagrams which accommodates the three fundamental categories of graphical object: points, lines and regions, uniformly. This representation permits a large variety of queries and processes to be performed on the graphical data using the extended relational algebra. We describe a relational picture editor, which we have implemented, which creates the diagrams in the first place and allows them to be displayed and modified. We discuss a low-level data structure, based on dynamic multipaging, which combines the best of the polygon and the pixel representations of pictures, and we examine the interactions of this data structure with the relational representation.