37,885 research outputs found
The NASA Astrophysics Data System: Architecture
The powerful discovery capabilities available in the ADS bibliographic
services are possible thanks to the design of a flexible search and retrieval
system based on a relational database model. Bibliographic records are stored
as a corpus of structured documents containing fielded data and metadata, while
discipline-specific knowledge is segregated in a set of files independent of
the bibliographic data itself.
The creation and management of links to both internal and external resources
associated with each bibliography in the database is made possible by
representing them as a set of document properties and their attributes.
To improve global access to the ADS data holdings, a number of mirror sites
have been created by cloning the database contents and software on a variety of
hardware and software platforms.
The procedures used to create and manage the database and its mirrors have
been written as a set of scripts that can be run in either an interactive or
unsupervised fashion.
The ADS can be accessed at http://adswww.harvard.eduComment: 25 pages, 8 figures, 3 table
The Most Influential Paper Gerard Salton Never Wrote
Gerard Salton is often credited with developing the vector space model
(VSM) for information retrieval (IR). Citations to Salton give the impression
that the VSM must have been articulated as an IR model sometime between
1970 and 1975. However, the VSM as it is understood today evolved over a
longer time period than is usually acknowledged, and an articulation of the
model and its assumptions did not appear in print until several years after
those assumptions had been criticized and alternative models proposed. An
often cited overview paper titled ???A Vector Space Model for Information
Retrieval??? (alleged to have been published in 1975) does not exist, and
citations to it represent a confusion of two 1975 articles, neither of which
were overviews of the VSM as a model of information retrieval. Until the
late 1970s, Salton did not present vector spaces as models of IR generally
but rather as models of specifi c computations. Citations to the phantom
paper refl ect an apparently widely held misconception that the operational
features and explanatory devices now associated with the VSM must have
been introduced at the same time it was fi rst proposed as an IR model.published or submitted for publicatio
Storing and Indexing Plan Derivations through Explanation-based Analysis of Retrieval Failures
Case-Based Planning (CBP) provides a way of scaling up domain-independent
planning to solve large problems in complex domains. It replaces the detailed
and lengthy search for a solution with the retrieval and adaptation of previous
planning experiences. In general, CBP has been demonstrated to improve
performance over generative (from-scratch) planning. However, the performance
improvements it provides are dependent on adequate judgements as to problem
similarity. In particular, although CBP may substantially reduce planning
effort overall, it is subject to a mis-retrieval problem. The success of CBP
depends on these retrieval errors being relatively rare. This paper describes
the design and implementation of a replay framework for the case-based planner
DERSNLP+EBL. DERSNLP+EBL extends current CBP methodology by incorporating
explanation-based learning techniques that allow it to explain and learn from
the retrieval failures it encounters. These techniques are used to refine
judgements about case similarity in response to feedback when a wrong decision
has been made. The same failure analysis is used in building the case library,
through the addition of repairing cases. Large problems are split and stored as
single goal subproblems. Multi-goal problems are stored only when these smaller
cases fail to be merged into a full solution. An empirical evaluation of this
approach demonstrates the advantage of learning from experienced retrieval
failure.Comment: See http://www.jair.org/ for any accompanying file
Digital Image Access & Retrieval
The 33th Annual Clinic on Library Applications of Data Processing, held at the University of Illinois at Urbana-Champaign in March of 1996, addressed the theme of "Digital Image Access & Retrieval." The papers from this conference cover a wide range of topics concerning digital imaging technology for visual resource collections. Papers covered three general areas: (1) systems, planning, and implementation; (2) automatic and semi-automatic indexing; and (3) preservation with the bulk of the conference focusing on indexing and retrieval.published or submitted for publicatio
- …