In this chapter we provide an overview of the main techniques for processing qualitative temporal constraints. We survey a collection of algorithms for solving fundamental reasoning problems in the context of Allen’s Interval Algebra, Vilain and Kautz’s Point Algebra, and of other tractable and intractable classes of temporal relations. These problems include determining the satisfiability of a...

A positive temporal template (or a positive temporal constraint language) is a relational structure whose relations can be defined over countable dense linear order without endpoints using a relational symbol ≤, logical conjunction and disjunction. This paper gives a complete complexity characterization for quantified constraint satisfaction problems (QCSP) over positive temporal languages. Alt...

We propose a framework for performing extensional and intensional temporal reasoning about qualitative and quantitative “periodicity-dependent” temporal constraints between repeated events, also considering user-defined periodicities.

Temporal integrity constraints are integrity constraints formulated over temporal databases. They can express dynamic properties by referring to data valid at different time points. This is to be contrasted with databases that do not store past or future information: if integrity constraints can only refer to data valid at the current time, they can only express static properties. Languages for...

The notion of time plays an important role in any intelligent activities Time is represented either im plicitly or explicitly We are interested in explicit representation of time The popular approaches for such representation are based on points or intervals or a hybrid of both Propositional temporal asser tions are represented as relations among the points or among the intervals The inde nite ...

We continue the development of a theory of constraint databases with indeenite information which we originated in our previous research. Initially we review the schemes of L-constraint databases and indeenite L-constraint databases where L, the parameter, is a rst-order constraint language. Then we consider several instances of these schemes where L is a language for expressing information abou...

A wide range of database applications manage information that varies over time. The conceptual modeling of databases is frequently based on one of the several versions of the ER model. As this model does not provide built-in means for capturing temporal aspects of data, the resulting diagrams are unnecessarily obscure and inadequate for documentation purposes. The TimeER model extends the ER mo...

In this paper we consider a class of integrity constraints which describe admissible lifecycles of database objects, and which can be speciied by transition graphs. We present an algorithmic scheme for monitoring such constraints in temporal databases which eeciently support the concept of valid-time. The keys to eecient monitoring lie in storing lifecycle situations with respect to constraints...

Policy evaluation is a process to determine whether a request submitted by a user satisfies the access control policies defined by an organization. Modality conflict is one of the main issues in policy evaluation. Existing modality conflict detection approaches do not consider complex condition attributes such as spatial and temporal constraints. An effective authorization propagation rule is n...