Precise specification matching for adaptive reuse in embedded systems

AbstractSpecification matching is a key to reuse of components in embedded systems. Existing specification matching techniques for embedded systems are designed to match reactive behaviors using adaptive techniques to dynamically alter behaviors. However, correct specification matching demands both behavioral matching (that checks component adaptability) and functional matching (that ensures that proper functionality is reused). While approaches for behavioral matching exist, combined functional and behavioral matching during component reuse in embedded systems is lacking. This paper presents a precise specification matching, including both behavioral and functional matching. We introduce attributed labeled transition systems (ALTS) to formally specify component behavior and functionalities. Given ALTS of a new specification (a function F) and an existing component (a device D), a new refinement relation from F to D, called an S-matching relation, is proposed for precise specification matching. The existence of an S-matching relation is also shown to be a necessary and sufficient condition for the existence of a correct adapter to adapt D to match F both behaviorally and functionally. Automated component adaptation is facilitated by a matching tool implemented in a tabled logic programming environment, which provides distinct advantages for rapid implementation. Practical examples are given to illustrate how the concrete adapter is derived automatically from specification matching

Supporting pruning in tabled LP

This paper analyzes issues which appear when supporting pruning operators in tabled LP. A version of the once/1 control predicate tailored for tabled predicates is presented, and an implementation analyzed and evaluated. Using once/1 with answer-on-demand strategies makes it possible to avoid computing unneeded solutions for problems which can benefit from tabled LP but in which only a single solution is needed, such as model checking and planning. The proposed version of once/1 is also directly applicable to the efficient implementation of other optimizations, such as early completion, cut-fail loops (to, e.g., prune at the top level), if-then-else, and constraint-based branch-and-bound optimization. Although once/1 still presents open issues such as dependencies of tabled solutions on program history, our experimental evaluation confirms that it provides an arbitrarily large efficiency improvement in several application areas

Justifying Proofs using Memo Tables

Tableau-based proof systems can be elegantly specified and directly executed by a tabled Logic Programming (LP) system. Our experience with the XMC model checker shows that such an encoding can be used to search for the existence of a proof very efficiently. However, the users of a tableau system are often interested in getting sufficient evidence (in terms of the tableau proof rules) on why a proof does or does not exist. In this paper, we address the problem of constructing such an evidence without introducing any additional computational overhead to the proof search. A tabled LP system maintains a memo table of "lemmas" that were tried and possibly proved during query evaluation. We propose the concept of justifier for extracting sufficient evidence for the truth or falsehood of literals in a logic program, by post-processing the memo tables created during query evaluation. Based on this logic program justifier, we showhow to construct evidence for the presence/absence of tableau in a tableau-based proof system. Weprovide experimental results showing the effectiveness of the justifier in constructing succinct evidence of the evaluation performed by the XMC model checker. Finally we discuss the role of the justifier as a programming abstraction for encoding efficient algorithms as tabled logic programs

Logic based modeling and analysis of workflows (Extended Abstract)

We propose Concurrent Transaction Logic (CT R) as the language for specifying, analyzing, and scheduling of work ows. We show that both local and global properties of work ows can be naturally represented as CT R formulas and reasoning can be done with the use of the proof theory and the semantics of this logic. We describe a transformation that leads to an e cient algorithm for scheduling work ows in the presence of global temporal constraints, which leads to decision procedures for dealing with several safety related properties such as whether every valid execution of the work ow satises a particular property or whether a work ow execution is consistent with some given global constraints on the ordering of events in a work ow. We also provide tight complexity results on the running times of these algorithms

Beyond tamaki-sato style unfold/fold transformations for normal logic programs

10.1142/S0129054102001175International Journal of Foundations of Computer Science133387-40