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1.
Locating and accessing data repositories with WebSemantics 总被引:1,自引:0,他引:1
George A. Mihaila Louiqa Raschid Anthony Tomasic 《The VLDB Journal The International Journal on Very Large Data Bases》2002,11(1):47-57
Many collections of scientific data in particular disciplines are available today on the World Wide Web. Most of these data
sources are compliant with some standard for interoperable access. In addition, sources may support a common semantics, i.e.,
a shared meaning for the data types and their domains. However, sharing data among a global community of users is still difficult
because of the following reasons: (i) data providers need a mechanism for describing and publishing available sources of data;
(ii) data administrators need a mechanism for discovering the location of published sources and obtaining metadata from these
sources; and (iii) users need a mechanism for browsing and selecting sources. This paper describes a system, WebSemantics,
that accomplishes the above tasks. We describe an architecture for the publication and discovery of scientific data sources,
which is an extension of the World Wide Web architecture and protocols. We support catalogs containing metadata about data
sources for some application domain. We define a language for discovering sources and querying their metadata. We then describe
the WebSemantics prototype.
Edited by H. Korth. Received: 15 July 1999 / Accepted: 13 September 2000 Published online: 16 April 2002 相似文献
2.
The cumbersome nature of wired interfaces often limits the range of application of virtual environments. In this paper, we
discuss the design and implementation of a novel system, called ALIVE, which allows unencumbered full-body interaction between
a human participant and a rich graphical world inhabited by autonomous agents. Based on results obtained with thousands of
users, the paper argues that this kind of system can provide more complex and very different experiences than traditional
virtual reality systems. The ALIVE system significantly broadens the range of potential applications of virtual reality systems;
in particular, the paper discusses novel applications in the area of training and teaching, entertainment, and digital assistants
or interface agents. We give an overview of the methods used in the implementation of the existing ALIVE systems. 相似文献
3.
Shahram Izadi Mike Fraser Steve Benford Martin Flintham Chris Greenhalgh Tom Rodden Holger Schnädelbach 《Personal and Ubiquitous Computing》2002,6(4):290-298
The Citywide project is exploring ways in which technology can provide people with rich and engaging digital experiences
as they move through physical space, including historical experiences, performances and games. This paper describes some initial
results and experiences with this project based upon two prototype demonstrators. In the first, we describe an application
in which a search party explores an archaeological site, uncovering enacted scenes within the virtual world that are of a
historical relevance to their particular physical location. In the second, we describe a museum experience where participants
explore an outdoors location, hunting for buried virtual artifacts that they then bring back to a museum for a more detailed
study. Our demonstrators employ a varied set of devices, including mobile wireless interfaces for locating hotspots of virtual
activity when outdoors, to give different experiences of the virtual world depending upon location, task, available equipment
and accuracy of tracking. We conclude by discussing some of the potential advantages of using an underlying shared virtual
world to support interactive experiences across extended physical settings. 相似文献
4.
Dialoguing with developers and suppliers of adaptive computer technologies: Data and recommendations
Jennison V. Asuncion Catherine S. Fichten Myrtis E. Fossey Maria Barile 《Universal Access in the Information Society》2002,1(3):177-196
The authors report on findings on computer technology needs and concerns of 725 Canadian college and university students with
a wide range of disabilities. The vast majority of this sample population uses computers and almost half need an adaptation
to use computers effectively. The authors provide information about computer technologies used by students with different
disabilities, describe adaptations/adaptive computer technologies that students find useful, report issues faced by users
and non-users of computers in postsecondary education, and discuss reasons why students are not using needed adaptations/adaptive
technology. Based on these findings, the authors provide recommendations for adaptive computer hardware and software developers
and vendors.
Published online: 21 March 2002 相似文献
5.
Massimo Mecella Barbara Pernici 《The VLDB Journal The International Journal on Very Large Data Bases》2001,10(1):2-15
Component-based approaches are becoming more and more popular to support Internet-based application development. Different
component modeling approaches, however, can be adopted, obtaining different abstraction levels (either conceptual or operational).
In this paper we present a component-based architecture for the design of e-applications, and discuss the concept of wrapper
components as building blocks for the development of e-services, where these services are based on legacy systems. We discuss
their characteristics and their applicability in Internet-based application development.
Received: 30 October 2000 / Accepted: 9 January 2001 Published online: 28 June 2001 相似文献
6.
Much work on video servers has concentrated on movies on demand, in which a relatively small number of titles are viewed
and users are given basic VCR-style controls. This paper concentrates on analyzing video server performance for non-linear
access applications. In particular, we study two non-linear video applications: video libraries, in which users select from
a large collection of videos and may be interested in viewing only a small part of the title; and video walk-throughs, in
which users can move through an image-mapped representation of a space. We present a characterization of the workloads of
these applications. Our simulation studies show that video server architectures developed for movies on demand can be adapted
to video library usage, though caching is less effective and the server can support a smaller user population for non-linear
video applications. We also show that video walk-throughs require extremely large amounts of RAM buffering to provide adequate
performance for even a small number of users. 相似文献
7.
Wen-Syan Li K.Selçuk Candan Kyoji Hirata Yoshinori Hara 《The VLDB Journal The International Journal on Very Large Data Bases》2001,9(4):312-326
Due to the fuzziness of query specification and media matching, multimedia retrieval is conducted by way of exploration.
It is essential to provide feedback so that users can visualize query reformulation alternatives and database content distribution.
Since media matching is an expensive task, another issue is how to efficiently support exploration so that the system is not
overloaded by perpetual query reformulation. In this paper, we present a uniform framework to represent statistical information
of both semantics and visual metadata for images in the databases. We propose the concept of query verification, which evaluates queries using statistics, and provides users with feedback, including the strictness and reformulation alternatives
of each query condition as well as estimated numbers of matches. With query verification, the system increases the efficiency
of the multimedia database exploration for both users and the system. Such statistical information is also utilized to support
progressive query processing and query relaxation.
Received: 9 June 1998/ Accepted: 21 July 2000 Published online: 4 May 2001 相似文献
8.
Steve Benford John Bowers Lennart E. Fahlén Chris Greenhalgh Dave Snowdon 《Multimedia Systems》1997,5(2):93-104
This paper explores the issue of user embodiment within collaborative virtual environments. By user embodiment we mean the
provision of users with appropriate body images so as to represent them to others and also to themselves. By collaborative
virtual environments we mean multi-user virtual reality systems which explicitly support cooperative work (although we argue
that the results of our exploration may also be applied to other kinds of collaborative system). The main part of the paper
identifies a list of embodiment design issues grouped by the general themes of personal representation, conveying activity,
embodiment in heterogeneous systems, embodiment of agents, and ethical issues. These issues are illustrated with examples
from our own DIVE and MASSIVE collaborative virtual environments. The paper also uses this set of issues as an analytical
framework for comparing a number of other communication technologies. 相似文献
9.
Anat Eyal Tova Milo 《The VLDB Journal The International Journal on Very Large Data Bases》2001,10(1):16-38
A broad spectrum of electronic commerce applications is currently available on the Web, providing services in almost any
area one can think of. As the number and variety of such applications grow, more business opportunities emerge for providing
new services based on the integration and customization of existing applications. (Web shopping malls and support for comparative
shopping are just a couple of examples.) Unfortunately, the diversity of applications in each specific domain and the disparity
of interfaces, application flows, actor roles in the business transaction, and data formats, renders the integration and manipulation
of applications a rather difficult task. In this paper we present the Application Manifold system, aimed at simplifying the intricate task of integration and customization of e-commerce applications. The scope of
the work in this paper is limited to web-enabled e-commerce applications. We do not support the integration/customization
of proprietary/legacy applications. The wrapping of such applications as web services is complementary to our work. Based
on the emerging Web data standard, XML, and application modeling standard, UML, the system offers a novel declarative specification
language for describing the integration/customization task, supporting a modular approach where new applications can be added
and integrated at will with minimal effort. Then, acting as an application generator, the system generates a full integrated/customized
e-commerce application, with the declarativity of the specification allowing for the optimization and verification of the
generated application. The integration here deals with the full profile of the given e-commerce applications: the various
services offered by the applications, the activities and roles of the different actors participating in the application (e.g.,
customers, vendors), the application flow, as well as with the data involved in the process. This is in contrast to previous
works on Web data integration that focused primarily on querying the data available in the applications, mostly ignoring the
additional aspects mentioned above.
Received: 30 October 2000 / Accepted 14 March 2001 Published online: 2 August 2001 相似文献
10.
Understanding and Using Context 总被引:49,自引:6,他引:43
Anind K. Dey 《Personal and Ubiquitous Computing》2001,5(1):4-7
Context is a poorly used source of information in our computing environments. As a result, we have an impoverished understanding
of what context is and how it can be used. In this paper, we provide an operational definition of context and discuss the
different ways in which context can be used by context-aware applications. We also present the Context Toolkit, an architecture
that supports the building of these context-aware applications. We discuss the features and abstractions in the toolkit that
make the task of building applications easier. Finally, we introduce a new abstraction, a situation which we believe will
provide additional support to application designers. 相似文献