11,166 research outputs found
Querying a Polynomial Object-Relational Constraint Database in Model-Based Diagnosis
Many papers related to Constraint Databases (CDBs) theories
exist, including proposals that present frameworks for the treatment
of constraints as a new data type. Our proposal presents a new way
of storing and manipulating constraints as a usual data, and of making
queries about the constraint variables derived from an Object-Relational
Constraint Database (ORCDB). In this work, the constraints stored in
an ORCDB are only polynomial equality constraints. The proposal is
based on Gr¨obner bases, constraint consistency and constraint optimisation
techniques. Most works in CDB use spatial-temporal data as a case
study, however this work presents an emergent engineering domain, that
of fault diagnosis.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
Distributed Model-Based Diagnosis using Object-Relational Constraint Databases
This work presents a proposal to diagnose distributed
systems utilizing model-based diagnosis using distributed
databases. In order to improve aspects as versatility, persistence,
easy composition and efficiency in the diagnosis
process we use an Object Relational Constraint Database
(ORCDB). Thereby we define a distributed architecture to
store the behaviour of components as constraints in a relational
database to diagnose a distributed system. This
work proposes an algorithm to detect which components fail
when their information is distributed in several databases,
and all the information is not available in a global way. It
is also offered a proposal to define, in execution time, the
allocation of the sensors in a distributed system.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
Developing a labelled object-relational constraint database architecture for the projection operator
Current relational databases have been developed in order to improve the handling of
stored data, however, there are some types of information that have to be analysed for
which no suitable tools are available. These new types of data can be represented and treated
as constraints, allowing a set of data to be represented through equations, inequations
and Boolean combinations of both. To this end, constraint databases were defined and
some prototypes were developed. Since there are aspects that can be improved, we propose
a new architecture called labelled object-relational constraint database (LORCDB). This provides
more expressiveness, since the database is adapted in order to support more types of
data, instead of the data having to be adapted to the database. In this paper, the projection
operator of SQL is extended so that it works with linear and polynomial constraints and
variables of constraints. In order to optimize query evaluation efficiency, some strategies
and algorithms have been used to obtain an efficient query plan.
Most work on constraint databases uses spatiotemporal data as case studies. However,
this paper proposes model-based diagnosis since it is a highly potential research area,
and model-based diagnosis permits more complicated queries than spatiotemporal examples.
Our architecture permits the queries over constraints to be defined over different sets
of variables by using symbolic substitution and elimination of variables.Ministerio de Ciencia y Tecnología DPI2006-15476-C02-0
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