Applying Constraint Databases in the Determination of Potential Minimal Conflicts to Polynomial Model-Based Diagnosis

Model-based Diagnosis allows the identification of the parts which fail in a system. The models are based on the knowledge of the system to diagnose, and may be represented by constraints associated to the components. The variables of these constraints can be observable or non-observable, depending on the situation of the sensors. In order to obtain the potential minimal diagnosis in a system, an important issue is related to finding out the potential minimal conflicts in an efficient way. We consider that Constraint Databases represent an excellent option in order to solve this problem in complex systems. In this work we have used a novel logical architecture of Constraint Databases which has allowed obtaining these potential conflicts by means of the corresponding queries. Moreover, we have considered Gröbner Bases as a projection operator to obtain the potential minimal conflicts of a system. The first results obtained on this work, which are shown in a heat exchangers example, have been very promising.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0

Constraint Databases Technology for Polynomial Models Diagnosis

Model-based Diagnosis allows the identification of the parts which fail in a system. The models are based on the knowledge of the system to diagnose, and they can be represented by constraints associated to the components. The variables including in these con straints can be observable or non-observable, depending on the situa tion of sensors. In order to obtain the minimal diagnosis in a system, an important issue is related to find out the minimal possible conflicts in an efficient way. We consider that Constraint Databases represent an excellent approach in order to solve this problem in complex sys tems, where a tuple in a relational database could be replaced by a conjunction of constraints. In this work we have used a novel logical architecture of Con straint Databases which has allowed us to obtain these possible min imal conflicts by means of a standard query language though the in formation is stored in a conventional relational database. Moreover, we have considered Grobner bases as a projection operator to obtain ¨ the minimal possible conflicts of a system.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0

Determination of Possible Minimal Conflict Sets Using Constraint Databases Technology and Clustering

Model-based Diagnosis allows the identification of the parts which fail in a system. The models are based on the knowledge of the system to diagnose, and can be represented by constraints associated to components. Inputs and outputs of components are represented as variables of those constraints, and they can be observable and non-observable depending on the situation of sensors. In order to obtain the minimal diagnosis in a system, an important issue is to find out the possible minimal conflicts in an efficient way. In this work, we propose a new approach to automate and to improve the determination of possible minimal conflict sets. This approach has two phases. In the first phase, we determine components clusters in the system in order to reduce drastically the number of contexts to consider. In the second phase, we construct a reduced context network with the possible minimal conflicts. In this phase we use Gröbner bases reduction.A novel logical architecture of Constraint Databases is used to store the model, the components clusters and possible minimal conflict sets. The necessary information in each phase is obtained by using a standard query language.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0

Strategic directions in constraint programming

An abstract is not available

On the Decidability of Semilinearity for Semialgebraic Sets and Its Implications for Spatial Databases

AbstractSeveral authors have suggested using first-order logic over the real numbers to describe spatial database applications. Geometric objects are then described by polynomial inequalities with integer coefficients involving the coordinates of the objects. Such geometric objects are called semialgebraic sets. Similarly, queries are expressed by polynomial inequalities. The query language thus obtained is usually referred to as FO+poly. From a practical point of view, it has been argued that a linear restriction of this so-called polynomial model is more desirable. In the so-called linear model, geometric objects are described by linear inequalities and are called semilinear sets. The language of the queries expressible by linear inequalities is usually referred to as FO+linear. As part of a general study of the feasibility of the linear model, we show in this paper that semilinearity is decidable for semialgebraic sets. In doing so, we point out important subtleties related to the type of the coefficients in the linear inequalities used to describe semilinear sets. An important concept in the development of the paper is regular stratification. We point out the geometric significance, as well as its significance in the context of FO+linear and FO+poly computations. The decidability of semilinearity of semialgebraic sets has an important consequence. It has been shown that it is undecidable whether a query expressible in FO+poly is linear, i.e., maps spatial databases of the linear model into spatial databases of the linear model. It follows now that, despite this negative result, there exists a syntactically definable language precisely expressing the linear queries expressible in FO+poly

Constraint Query Algebras

Constraint query languages are natural extensions of relational database query languages. A framework for their declarative speci cation (constraint calculi) and e cient implementation (low data complexity and secondary storage indexing) was presented in Kanellakis et al., 1995. Constraint query algebras form a procedural language layer between high-level declarative calculi and low-level indexing methods. Just like the relational algebra, this intermediate layer can be very useful for program optimization. In this paper, we study properties of constraint query algebras, which wepresent through three concrete examples. The dense order constraint algebra illustrates how the appropriate canonical form can simplify expensive operations, such as projection, and facilitate interaction with updates. The monotone two-variable linear constraint algebra illustrates the concept of strongly polynomial operations. Finally, thelazy evaluation of (non)linear constraint algebras illustrates how large numbers of (non)linear constraints could be implemented with only a small amount of costly symbolic processing

Constraint Query Algebras

Pages : : : University Microfilms Agreement (signed): : : Survey of Earned Doctorates : : : Career Plans Questionnaire : : : Constraint Query Algebras by Dina Q Goldin B.A. Yale University, 1985 M.S. Brown University, 1987 Thesis Submitted in partial fulfillment of the requirements for the Degree of Doctor of Philosophy in the Department of Computer Science at Brown University Copyright by Dina Q Goldin 1997 This dissertation by Dina Q Goldin is accepted in its present form by the Department of Computer Science as satisfying the dissertation requirement for the degree of Doctor of Philosophy

The Constraint Database Framework: Lessons Learned from CQA/CDB

This paper reflects our experience with CQA/CDB, a prototype rational linear constraint database. First, we show that the standard semantics of constraint databases lead to an anomaly when queried in the presence of missing attributes. In CQA/CDB, this anomaly is avoided by enriching the CDB relational schema, resulting in heterogenous databases. Then, we present spatial databases as a special case of heterogenous databases and extend constraint query algebras (CQAs) with two additional spatial operators, proving that the resulting language is safe for linear constraints