2,328 research outputs found
Executable First-Order Queries in the Logic of Information Flows
The logic of information flows (LIF) has recently been proposed as a general
framework in the field of knowledge representation. In this framework, tasks of
a procedural nature can still be modeled in a declarative, logic-based fashion.
In this paper, we focus on the task of query processing under limited access
patterns, a well-studied problem in the database literature. We show that LIF
is well-suited for modeling this task. Toward this goal, we introduce a variant
of LIF called "forward" LIF, in a first-order setting. We define FLIFio, a
syntactical fragment of forward LIF, and show that it corresponds exactly to
the "executable" fragment of first-order logic defined by Nash and Lud\"ascher.
Moreover, we show that general FLIF expressions can also be put into
io-disjoint form. The definition of FLIFio involves a classification of the
free variables of an expression into "input" and "output" variables. Our result
hinges on inertia and determinacy laws for forward LIF expressions, which are
interesting in their own right. These laws are formulated in terms of the input
and output variables.Comment: This paper is the extended version of the two papers presented at
ICDT 2020 and ICDT 202
Linking data and BPMN processes to achieve executable models
We describe a formally well founded approach to link data and processes conceptually, based on adopting UML class diagrams to represent data, and BPMN to represent the process. The UML class diagram together with a set of additional process variables, called Artifact, form the information model of the process. All activities of the BPMN process refer to such an information model by means of OCL operation contracts. We show that the resulting semantics while abstract is fully executable. We also provide an implementation of the executor.Peer ReviewedPostprint (author's final draft
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