A detailed investigation of the behaviour of a new printable photochromic time-temperature indicator (TTI) was conducted to characterise its properties under specific temperature conditions and to analyse the influence of ultra violet (UV) light irradiation (activation) on the discolouration process. The reproducibility of the charging process and the discolouration process of the TTI were analysed. For different charging times the calculated activation energies based on the Arrhenius model ranged from 23.2 to 25.3 kcal mol )1 depending on the UV light irradiation (charging time). A quality contour diagram was established to define the appropriate charging time for different kinds of products. Due to the possibility of defining the shelf life of a TTI by different charging times, this novel TTI constitutes a reliable tool to monitor the cold chains of a broad range of food products on their way from production to consumption.

Abstract. We present HYPROLOG, a novel integration of Prolog with assumptions and abduction which is implemented in and partly borrows syntax from Constraint Handling Rules (CHR) for integrity constraints. Assumptions are a mechanism inspired by linear logic and taken over from Assumption Grammars. The language shows a novel flexibility in the interaction between the different paradigms, including all additional built-in predicates and constraints solvers that may be available. Assumptions and abduction are especially useful for language processing, and we can show how HYPROLOG works seamlessly together with the grammar notation provided by the underlying Prolog system. An operational semantics is given which complies with standard declarative semantics for the "pure" sublanguages, while for the full HYPROLOG language, it must be taken as definition. The implementation is straightforward and seems to provide for abduction, the most efficient of known implementations; the price, however, is a limited use of negations. The main difference wrt. previous implementations of abduction is that we avoid any level of metainterpretation by having Prolog execute the deductive steps directly and by treating abducibles (and assumptions as well) as CHR constraints.

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Abstract. Complete checks of database integrity constraints may be prohibitively time consuming, and several methods have been suggested for producing simplified checks for each update. The present approach introduces a set of transformation operators that apply to database integrity constraints with each operator representing a concise, semanticspreserving operation. These operators are applied in a procedure producing simplified constraints for parametric transaction patterns, which then can be instantiated and checked for consistency at run-time but before any transaction is executed. The operators provide a flexibility for other database enhancements and the work may also be seen as more systematic and general when compared with other approaches. The framework is formulated with first-order clause logic but with the perspective of being applied with present-day database technology.