Confluence of CHR Revisited:Invariants and Modulo Equivalence

Abstract simulation of one transition system by another is introduced as a means to simulate a potentially infinite class of similar transition sequences within a single transition sequence. This is useful for proving confluence under invariants of a given system, as it may reduce the number of proof cases to consider from infinity to a finite number. The classical confluence results for Constraint Handling Rules (CHR) can be explained in this way, using CHR as a simulation of itself. Using an abstract simulation based on a ground representation, we extend these results to include confluence under invariant and modulo equivalence, which have not been done in a satisfactory way before.Comment: Pre-proceedings paper presented at the 28th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2018), Frankfurt am Main, Germany, 4-6 September 2018 (arXiv:1808.03326

Engineering an Advanced Location-Based Augmented Reality Engine for Smart Mobile Devices

Daily business routines more and more require to access information systems in a mobile manner, while preserving a desktop-like feeling at the same time. The goal of this work is to outline the engineering process of a sophisticated mobile service running on a smartphone. More precisely, we show how to develop the core of a location-based augmented reality engine for the iPhone 4S based on the operating system iOS 5.1 (or higher). We denote this engine as AREA. In particular, we develop concepts for coping with limited resources on a mobile device, while providing a smooth user augmented reality experience at the same time. We further present and develop a suitable application architecture in this context, which easily allows integrating augmented reality with a wide range of applications

Correct Configuration of Process Variants in Provop

When engineering process-aware information systems (PAISs) one of the fundamental challenges is to cope with the variability of business processes. While some progress has been achieved regarding the configuration of process variants, there exists only little work on how to accomplish this in a correct manner. Configuring process variants constitutes a non-trivial challenge when considering the large number of process variants that exist in practice as well as the many syntactical and semantical constraints a configured process variant has to obey in a given context. In previous work we introduced the Provop approach for configuring and managing process variants. This paper picks up the Provop framework and shows how it ensures correctness of configurable process variants by construction. We discuss advanced concepts for the context- and constraint-based configuration of process variants, and show how they can be utilized to ensure correctness of the configured process variants. In this paper we also consider correctness issues in conjunction with dynamic variant re-configurations. Enhancing PAISs with the capability to correctly configure process models fitting to the given application context, and to correctly manage the resulting process variants afterwards, will enable a new quality in PAIS engineering