446,856 research outputs found
Databases Reduction Simultaneously by Ordered Projection
In this paper, a new algorithm Database Reduction Simulta neously by Ordered Projections (RESOP) is introduced. This algorithm
reduces databases in two directions: editing examples and feature se lection simultaneously. Ordered projections techniques have been used
to design RESOP taking advantage of symmetrical ideas for two dif ferent task. Experimental results have been made with UCI Repository
databases and the performance for the latter application of classification
techniques has been satisfactor
The combined approach to ontology-based data access
The use of ontologies for accessing data is one of
the most exciting new applications of description
logics in databases and other information systems.
A realistic way of realising sufficiently scalable ontology-
based data access in practice is by reduction
to querying relational databases. In this paper,
we describe the combined approach, which incorporates
the information given by the ontology into
the data and employs query rewriting to eliminate
spurious answers. We illustrate this approach for
ontologies given in the DL-Lite family of description
logics and briefly discuss the results obtained
for the EL family
Duplicate Detection in Probabilistic Data
Collected data often contains uncertainties. Probabilistic databases have been proposed to manage uncertain data. To combine data from multiple autonomous probabilistic databases, an integration of probabilistic data has to be performed. Until now, however, data integration approaches have focused on the integration of certain source data (relational or XML). There is no work on the integration of uncertain (esp. probabilistic) source data so far. In this paper, we present a first step towards a concise consolidation of probabilistic data. We focus on duplicate detection as a representative and essential step in an integration process. We present techniques for identifying multiple probabilistic representations of the same real-world entities. Furthermore, for increasing the efficiency of the duplicate detection process we introduce search space reduction methods adapted to probabilistic data
Residual acceleration data on IML-1: Development of a data reduction and dissemination plan
The research performed consisted of three stages: (1) identification of sensitive IML-1 experiments and sensitivity ranges by order of magnitude estimates, numerical modeling, and investigator input; (2) research and development towards reduction, supplementation, and dissemination of residual acceleration data; and (3) implementation of the plan on existing acceleration databases
Improving the Evolutionary Coding for Machine Learning Tasks
The most influential factors in the quality of the solutions
found by an evolutionary algorithm are a correct coding of the
search space and an appropriate evaluation function of the potential
solutions. The coding of the search space for the obtaining of decision
rules is approached, i.e., the representation of the individuals of
the genetic population. Two new methods for encoding discrete and
continuous attributes are presented. Our “natural coding” uses one
gene per attribute (continuous or discrete) leading to a reduction in
the search space. Genetic operators for this approached natural coding
are formally described and the reduction of the size of the search
space is analysed for several databases from the UCI machine learning
repository.Comisión Interministerial de Ciencia y Tecnología TIC1143–C03–0
Hormone replacement therapy and prevention of vertebral fractures: a meta-analysis of randomised trials
BACKGROUND: Hormone replacement therapy (HRT) is often seen as the treatment of choice for preventing fractures in women. We undertook a recent meta-analysis of randomised trials which suggested that HRT reduced non-vertebral fractures by 30%. In this analysis we extend that analysis to vertebral fractures. METHODS: We searched the main electronic databases until the end of August 2001. We sought all randomised controlled trials (RCTs) of HRT where women had been randomised to at least 12 months of HRT or to no HRT. RESULTS: We found 13 RCTs. Overall there was a 33% reduction in vertebral factures (95% confidence interval (CI) 45% to 98%). CONCLUSIONS: This review and meta-analysis showed a significant reduction in vertebral fractures associated with HRT use
Towards a Holistic Integration of Spreadsheets with Databases: A Scalable Storage Engine for Presentational Data Management
Spreadsheet software is the tool of choice for interactive ad-hoc data
management, with adoption by billions of users. However, spreadsheets are not
scalable, unlike database systems. On the other hand, database systems, while
highly scalable, do not support interactivity as a first-class primitive. We
are developing DataSpread, to holistically integrate spreadsheets as a
front-end interface with databases as a back-end datastore, providing
scalability to spreadsheets, and interactivity to databases, an integration we
term presentational data management (PDM). In this paper, we make a first step
towards this vision: developing a storage engine for PDM, studying how to
flexibly represent spreadsheet data within a database and how to support and
maintain access by position. We first conduct an extensive survey of
spreadsheet use to motivate our functional requirements for a storage engine
for PDM. We develop a natural set of mechanisms for flexibly representing
spreadsheet data and demonstrate that identifying the optimal representation is
NP-Hard; however, we develop an efficient approach to identify the optimal
representation from an important and intuitive subclass of representations. We
extend our mechanisms with positional access mechanisms that don't suffer from
cascading update issues, leading to constant time access and modification
performance. We evaluate these representations on a workload of typical
spreadsheets and spreadsheet operations, providing up to 20% reduction in
storage, and up to 50% reduction in formula evaluation time
PLANT ENTRY AND EXIT FROM THE MEATPACKING INDUSTRY DURING PATHOGEN REDUCTION AND HACCP IMPLEMENTATION
Implementation of the Pathogen Reduction and Hazard Analysis and Critical Control Points (PR/HACCP) regulations has now occurred across all U.S. meat and poultry plants. Using databases of plants under federal inspection, we estimate a probit model to determine which factors have affected the probability of exit of meat slaughtering plants during implementation of the regulations.Industrial Organization, Livestock Production/Industries,
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