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1.
The traditional style of working with computers generally revolves around the computer being used as a tool, with individual
users directly initiating operations and waiting for the results of them. A more recent paradigm of human-computer interaction,
based on the indirect management of computing resources, is agent-based interaction. The idea of delegation plays a key part
in this approach to computer-based work, which allows individuals to relinquish the routine, mechanistic parts of their everyday
tasks, having them performed automatically instead. Adaptive interfaces combine elements of both these approaches, where the
goal is to have the interface adapt to its users rather than the reverse. This paper addresses some of the issues arising
from a practical software development process which aimed to support individuals using this style of interaction. This paper
documents the development of a set of classes which implement an architecture for adaptive interfaces. These classes are intended
to be used as part of larger user interface systems which are to exhibit adaptive behaviour. One approach to the implementation
of an adaptive interface is to use a set of software “agents”– simple processes which effectively run “in the background”–
to decompose the task of implementing the interface. These agents form part of a larger adaptive interface architecture, which
in turn forms a component of the adaptive system. 相似文献
2.
Deadlock detection in distributed database systems: a new algorithm and a comparative performance analysis 总被引:4,自引:0,他引:4
Natalija Krivokapić Alfons Kemper Ehud Gudes 《The VLDB Journal The International Journal on Very Large Data Bases》1999,8(2):79-100
This paper attempts a comprehensive study of deadlock detection in distributed database systems. First, the two predominant
deadlock models in these systems and the four different distributed deadlock detection approaches are discussed. Afterwards,
a new deadlock detection algorithm is presented. The algorithm is based on dynamically creating deadlock detection agents (DDAs), each being responsible for detecting deadlocks in one connected component of the global wait-for-graph (WFG). The
DDA scheme is a “self-tuning” system: after an initial warm-up phase, dedicated DDAs will be formed for “centers of locality”,
i.e., parts of the system where many conflicts occur. A dynamic shift in locality of the distributed system will be responded
to by automatically creating new DDAs while the obsolete ones terminate. In this paper, we also compare the most competitive
representative of each class of algorithms suitable for distributed database systems based on a simulation model, and point
out their relative strengths and weaknesses. The extensive experiments we carried out indicate that our newly proposed deadlock
detection algorithm outperforms the other algorithms in the vast majority of configurations and workloads and, in contrast
to all other algorithms, is very robust with respect to differing load and access profiles.
Received December 4, 1997 / Accepted February 2, 1999 相似文献
3.
TELEPORT is an experimental teleconferencing system with the goal of enabling small groups of people, although geographically
separated, to meet as if face to face. The innovative features of the system include the use of full-wall display surfaces,
“merging” of real and virtual environments, viewer tracking, and real-time compositing of live video with synthetic backgrounds. 相似文献
4.
Design and analysis of a video-on-demand server 总被引:6,自引:0,他引:6
The availability of high-speed networks, fast computers and improved storage technology is stimulating interest in the development
of video on-demand services that provide facilities similar to a video cassette player (VCP). In this paper, we present a
design of a video-on-demand (VOD) server, capable of supporting a large number of video requests with complete functionality
of a remote control (as used in VCPs), for each request. In the proposed design, we have used an interleaved storage method
with constrained allocation of video and audio blocks on the disk to provide continuous retrieval. Our storage scheme interleaves
a movie with itself (while satisfying the constraints on video and audio block allocation. This approach minimizes the starting delay and the
buffer requirement at the user end, while ensuring a jitter-free display for every request. In order to minimize the starting
delay and to support more non-concurrent requests, we have proposed the use of multiple disks for the same movie. Since a
disk needs to hold only one movie, an array of inexpensive disks can be used, which reduces the overall cost of the proposed
system. A scheme supported by our disk storage method to provide all the functions of a remote control such as “fast-forwarding”,
“rewinding” (with play “on” or “off”), “pause” and “play” has also been discussed. This scheme handles a user request independent
of others and satisfies it without degrading the quality of service to other users. The server design presented in this paper
achieves the multiple goals of high disk utilization, global buffer optimization, cost-effectiveness and high-quality service
to the users. 相似文献
5.
Scott D. Stoller 《Distributed Computing》2000,13(2):85-98
Summary. This paper proposes a framework for detecting global state predicates in systems of processes with approximately-synchronized
real-time clocks. Timestamps from these clocks are used to define two orderings on events: “definitely occurred before” and
“possibly occurred before”. These orderings lead naturally to definitions of 3 distinct detection modalities, i.e., 3 meanings of “predicate held during a computation”, namely: (“ possibly held”), (“ definitely held”), and (“ definitely held in a specific global state”). This paper defines these modalities and gives efficient algorithms for detecting
them. The algorithms are based on algorithms of Garg and Waldecker, Alagar and Venkatesan, Cooper and Marzullo, and Fromentin
and Raynal. Complexity analysis shows that under reasonable assumptions, these real-time-clock-based detection algorithms
are less expensive than detection algorithms based on Lamport's happened-before ordering. Sample applications are given to
illustrate the benefits of this approach.
Received: January 1999 / Accepted: November 1999 相似文献
6.
S. Arbanowski S. van der Meer S. Steglich R. Popescu-Zeletin 《Personal and Ubiquitous Computing》2001,5(1):34-37
In the last few years, a variety of concepts for service integration and corresponding systems have been developed. On the
one hand, they aim for the interworking and integration of classical telecommunications and data communications services.
On the other, they are focusing on universal service access from a variety of end-user systems. Many of the technical problems,
resulting from the service integration, and service personalisation have been solved during the last years. However, all these
systems are driven by the concept of providing several technologies to users by keeping the peculiarity of each service.
Looking at humans’ communication behaviour and their communication space, it is obvious that human beings interact habitually
in a set of contexts with their environment. The individual information preferences and needs, persons to interact with, and
the set of devices controlled by each individual define their personal communication space. Following this view, a new approach
is to build communication systems not on the basis of specific technologies, but on the analysis of the individual communication
spaces. The result is a communication system adapted to the demands of each individual (I-centric). The communication system
will act on behalf of users’ demands, reflecting recent actions to enable profiling and self-adaptation to contexts and situations.
In this paper, we introduce I-centric Communications, an approach to design communication systems that adapt themselves to
the individual communication space and individual environment and situation. In this context “I” means I, or individual, “Centric”
means adaptable to I requirements and a certain user environment. 相似文献
7.
Xiangyun Ye Mohamed Cheriet Ching Y. Suen 《International Journal on Document Analysis and Recognition》2001,4(2):84-96
The automation of business form processing is attracting intensive research interests due to its wide application and its
reduction of the heavy workload due to manual processing. Preparing clean and clear images for the recognition engines is
often taken for granted as a trivial task that requires little attention. In reality, handwritten data usually touch or cross
the preprinted form frames and texts, creating tremendous problems for the recognition engines. In this paper, we contribute
answers to two questions: “Why do we need cleaning and enhancement procedures in form processing systems?” and “How can we
clean and enhance the hand-filled items with easy implementation and high processing speed?” Here, we propose a generic system
including only cleaning and enhancing phases. In the cleaning phase, the system registers a template to the input form by
aligning corresponding landmarks. A unified morphological scheme is proposed to remove the form frames and restore the broken
handwriting from gray or binary images. When the handwriting is found touching or crossing preprinted texts, morphological
operations based on statistical features are used to clean it. In applications where a black-and-white scanning mode is adopted,
handwriting may contain broken or hollow strokes due to improper thresholding parameters. Therefore, we have designed a module
to enhance the image quality based on morphological operations. Subjective and objective evaluations have been studied to
show the effectiveness of the proposed procedures.
Received January 19, 2000 / Revised March 20, 2001 相似文献
8.
C. Stary 《Universal Access in the Information Society》2001,1(1):16-30
This paper addresses user modelling for “Design for All” in a model-based approach to Human-Computer Interaction, paying particular
attention to placing user models within organisational role- and task-related contexts. After reviewing a variety of user
modelling approaches, and deriving requirements for user modelling related to Design for All, the paper proposes a role-driven
individualised approach. Such an approach is based on a model-based representation schema and a unifying notation that keeps
the user’s models and the contextual information transparent and consistent. Individualisation is achieved by coupling symbolic
model specifications with neural networking on synchronisation links between symbolic representation elements. As a result,
user modelling for Design for All is achieved not by stereotypical user properties and functional roles, but by accommodating
the actual users’ behaviour.
Published online: 18 May 2001 相似文献
9.
This paper proposes a new hand-held device called “InfoPoint” that allows appliances to work together over a network. We
have applied the idea of “drag-and-drop” operation as provided in the GUIs of PC and workstation desktop environment. InfoPoint
provides a unified interface that gives different types of appliances “drag-and-drop”-like behaviour for the transfer of data.
Moreover, it can transfer data from/to non-appliances such as pieces of paper. As a result, InfoPoint allows appliances to
work together, in the real-world environment, in terms of data transfer. A prototype of InfoPoint has been implemented and
several experimental applications have been investigated. InfoPoint has shown its applicability in a variety of circumstances.
We believe that the idea proposed in this paper will be a significant technology in the network of the future. 相似文献
10.
As multimedia applications spread widely, it is crucial for programming and design support systems to handle “time” in multimedia
documents effectively and flexibly. This paper presents a set of interactive system support tools for designing and maintaining
the temporal behavior of multimedia documents. The tool set provides mechanisms for anomaly detection, temporal query processing,
and interactive scheduling. It is based on a fast incremental constraint solver we have developed, which can be adapted by
any constraint-based system. The incremental constraint solver provides immediate feedback to the user, supporting a highly
interactive design process. Combined with existing optimal layout generation mechanisms proposed in the literature, our tools
effectively utilize the flexibility provided by constraint-based systems. 相似文献
11.
One key component in providing effective image data management support is an expressive query language/interface. In this
paper, we describe the EXQUISI system that we have developed. A main contribution of EXQUISI is its ability to allow a user
to express subtle differences that may exist between images to be retrieved and other images that are similar. In particular,
it allows the user to incorporate ambiguities and imprecisions in specifying his/her query. Another important aspect of EXQUISI
is the provision of a reformulation language by which the user can ask “like this in what” queries, by specifying which parts
of a returned image the user wants to include and exclude. 相似文献
12.
Personalized, interactive news on the Web 总被引:2,自引:0,他引:2
We present Krakatoa Chronicle, an interactive, personalized newspaper on the World Wide Web implemented as a Java applet. The newspaper is similar in appearance
to newspapers in the real world, with a multi-column layout and justified text. At the same time, it provides various interaction
techniques for browsing the content of articles, giving relevance feedback, and dynamically changing layout. As users interact
with the system, individual ‘user profiles’ are built up at the webserver site. These are used to tailor the newspaper's content
and layout to each user's declared and inferred preferences. The system allows for a balancing of personal and community interests,
allowing the user to navigate through a space of newspapers corresponding to a range of viewpoints. 相似文献
13.
Lawrence D. Bergman Jerre Shoudt Vittorio Castelli Chung-Sheng Li Loey Knapp 《International Journal on Digital Libraries》1999,2(2-3):178-189
In this paper, we describe a new interface for querying multimedia digital libraries and an interface building framework.
The interface employs a drag-and-drop style of interaction and combines a structured natural-language style query specification
with reusable multimedia objects. We call this interface DanDMM, short for “drag-and-drop multimedia”. DanDMM interfaces capture
the syntax of the underlying query language, and dynamically reconfigure to reflect the contents of the data repository.
A distinguishing feature of DanDMM is its ability to synthesize integrated interfaces that incorporate both example-based
specification using multimedia objects, and traditional techniques including keyword, attribute, and free text-based search.
We describe the DanDMM-builder, a framework for synthesizing DanDMM interfaces, and give several examples of interfaces that
have been constructed using DanDMM-builder, including a remote-sensing library application and a video digital library.
Received: 15 December 1997 / Revised: June 1999 相似文献
14.
Michiharu Kudo 《International Journal of Information Security》2002,1(2):116-130
Over the years a wide variety of access control models and policies have been proposed, and almost all the models have assumed
“grant the access request or deny it.” They do not provide any mechanism that enables us to bind authorization rules with
required operations such as logging and encryption. We propose the notion of a “provisional action” that tells the user that
his request will be authorized provided he (and/or the system) takes certain actions. The major advantage of our approach
is that arbitrary actions such as cryptographic operations can all coexist in the access control policy rules. We define a
fundamental authorization mechanism and then formalize a provision-based access control model. We also present algorithms
and describe their algorithmic complexity. Finally, we illustrate how provisional access control policy rules can be specified
effectively in practical usage scenarios.
Published online: 22 January 2002 相似文献
15.
NeTra: A toolbox for navigating large image databases 总被引:17,自引:0,他引:17
We present here an implementation of NeTra, a prototype image retrieval system that uses color, texture, shape and spatial
location information in segmented image regions to search and retrieve similar regions from the database. A distinguishing
aspect of this system is its incorporation of a robust automated image segmentation algorithm that allows object- or region-based
search. Image segmentation significantly improves the quality of image retrieval when images contain multiple complex objects.
Images are segmented into homogeneous regions at the time of ingest into the database, and image attributes that represent
each of these regions are computed. In addition to image segmentation, other important components of the system include an
efficient color representation, and indexing of color, texture, and shape features for fast search and retrieval. This representation
allows the user to compose interesting queries such as “retrieve all images that contain regions that have the color of object
A, texture of object B, shape of object C, and lie in the upper of the image”, where the individual objects could be regions
belonging to different images. A Java-based web implementation of NeTra is available at http://vivaldi.ece.ucsb.edu/Netra. 相似文献
16.
In this paper we describe the fundamental principles that guide our work process at 5050 Ltd, in developing concepts and
prototypes for personal technology devices. We maintain that in designing personal devices it is critical to address the social
interaction elements of the user experience. We introduce the term “social functionality” to refer to those aspects of a device
that are specifically designed to elicit sociability and serendipity. It also refers to those aspects which enable users to
communicate or represent individuating characteristics through the use of their device. Social functionality is seen as a
critical success factor in the design of future personal devices. Introducing social functionality in personal technology
devices requires a multidisciplinary approach. Design and technology are seen as inseparable elements of the development process.
The mbracelet1, a wearable prototype we developed for, and in association with, NCR’s The Knowledge Lab, is used as a case in point. 相似文献
17.
We present a new approach to the tracking of very non-rigid patterns of motion, such as water flowing down a stream. The
algorithm is based on a “disturbance map”, which is obtained by linearly subtracting the temporal average of the previous
frames from the new frame. Every local motion creates a disturbance having the form of a wave, with a “head” at the present
position of the motion and a historical “tail” that indicates the previous locations of that motion. These disturbances serve
as loci of attraction for “tracking particles” that are scattered throughout the image. The algorithm is very fast and can
be performed in real time. We provide excellent tracking results on various complex sequences, using both stabilized and moving
cameras, showing a busy ant column, waterfalls, rapids and flowing streams, shoppers in a mall, and cars in a traffic intersection.
Received: 24 June 1997 / Accepted: 30 July 1998 相似文献
18.
A labelling approach for the automatic recognition of tables of contents (ToC) is described in this paper. A prototype is
used for the electronic consulting of scientific papers in a digital library system named Calliope. This method operates on
a roughly structured ASCII file, produced by OCR. The recognition approach operates by text labelling without using any a
priori model. Labelling is based on part-of-speech tagging (PoS) which is initiated by a primary labelling of text components
using some specific dictionaries. Significant tags are first grouped into homogeneous classes according to their grammar categories
and then reduced in canonical forms corresponding to article fields: “title” and “authors”. Non-labelled tokens are integrated
in one or another field by either applying PoS correction rules or using a structure model generated from well-detected articles.
The designed prototype operates very well on different ToC layouts and character recognition qualities. Without manual intervention,
a 96.3% rate of correct segmentation was obtained on 38 journals, including 2,020 articles, accompanied by a 93.0% rate of
correct field extraction.
Received April 5, 2000 / Revised February 19, 2001 相似文献
19.
Flip Korn Alexandros Labrinidis Yannis Kotidis Christos Faloutsos 《The VLDB Journal The International Journal on Very Large Data Bases》2000,8(3-4):254-266
Association Rule Mining algorithms operate on a data matrix (e.g., customers products) to derive association rules [AIS93b, SA96]. We propose a new paradigm, namely, Ratio Rules, which are quantifiable in that we can measure the “goodness” of a set of discovered rules. We also propose the “guessing
error” as a measure of the “goodness”, that is, the root-mean-square error of the reconstructed values of the cells of the
given matrix, when we pretend that they are unknown. Another contribution is a novel method to guess missing/hidden values
from the Ratio Rules that our method derives. For example, if somebody bought $10 of milk and $3 of bread, our rules can “guess”
the amount spent on butter. Thus, unlike association rules, Ratio Rules can perform a variety of important tasks such as forecasting,
answering “what-if” scenarios, detecting outliers, and visualizing the data. Moreover, we show that we can compute Ratio Rules
in a single pass over the data set with small memory requirements (a few small matrices), in contrast to association rule mining methods
which require multiple passes and/or large memory. Experiments on several real data sets (e.g., basketball and baseball statistics,
biological data) demonstrate that the proposed method: (a) leads to rules that make sense; (b) can find large itemsets in
binary matrices, even in the presence of noise; and (c) consistently achieves a “guessing error” of up to 5 times less than
using straightforward column averages.
Received: March 15, 1999 / Accepted: November 1, 1999 相似文献
20.
Marieke Huisman Bart Jacobs Joachim van den Berg 《International Journal on Software Tools for Technology Transfer (STTT)》2001,3(3):332-352
This paper presents a verification of an invariant property for the Vector class from JAVA’s standard library (API). The property
says (essentially) that the actual size of a vector is less than or equal to its capacity. It is shown that this “safety”
or “data integrity” property is maintained by all methods of the Vector class, and that it holds for all objects created by
the constructors of the Vector class. The verification of the Vector class invariant is done with the proof tool PVS. It is
based on a semantics of JAVA in higher order logic. The latter is incorporated in a special purpose compiler, the LOOP tool,
which translates JAVA classes into logical theories. It has been applied to the Vector class for this case study. The actual
verification takes into account the object-oriented character of JAVA: (non-final) methods may always be overridden, so that
one cannot rely on a particular implementation. Instead, one has to reason from method specifications in such cases. This
project demonstrates the feasibility of tool-assisted verification of non-trivial properties for non-trivial JAVA classes.
Published online: 10 May 2001 相似文献