The schema of a system consists of the constructs that model its entities. Schema evolution is the timely change and management of the schema. Dynamic schema evolution is the management of schema changes while the system is in operation. We propose a sound and complete axiomatic model for dynamic schema evolution in objectbase management systems (OBMSs) that support subtyping and property inher...

When genetic algorithms are used to evolve decision trees, key tree quality parameters can be recursively computed and re-used across generations of partially similar decision trees. Simply storing instance indices at leaves is enough for fitness to be piecewise computed in a lossless fashion. We show the derivation of the (substantial) expected speed-up on two bounding case problems and trace ...

A semantic net system in which knowled; ge is topically organized around concepts has been under development at the University of Alberta for some time. The system is capable of automatic topical classification of modal logic input sentences, concept and topic oriented retrieval, and property inheritance of a general sort. This paper presents an inference method which efficiently determines yes...

A semantic definition is given for instance-based pointer confinement (alias control); this provides a form of encapsulation suited to many object-oriented designs. A syntax-directed static analysis is defined and proved, using a compositional semantics, to imply semantic confinement. Previous work by the authors, reviewed here, shows that this notion of confinement ensures a strong information...

South Africa’s Master of the High Court administers property inheritance. Described as a ‘creature statute’, and staffed by legally trained officials, law takes centre-stage. Focusing on Johannesburg, Master’s biggest busiest branch, this article examines how is performed in bureaucratic encounters, shapes everyday relations that make legal bureaucrats middle-class professionals. Middle-class s...

Most comparisons among OO languages focus on structural or philosophical features but rarely on dynamic ones. Beyond all these structural properties, late-binding is, to our opinion, the key property of OO paradigm; the operational consequence of inheritance use. All OO languages use late-binding, but do they all have the same interpretation? We show that the answer is no, not very surprisingly...

This paper describes how routers can be used for factory communications. This statement is based on QoS management features of the IP protocol, especially schedulers, shapers, markers, filters that can be used and the ability of IP datagrams to carry priority in the ToS field for Ipv4 or the DS field for Ipv6. This last property allows priority inheritance of real-time threads across a factory ...

An ordinal view of independence is studied in the framework of possibility theory. We investigate three possible definitions of dependence, of increasing strength. One of them is the counterpart to the multiplication law in probability theory, and the two others are based on the notion of conditional possibility. These two have enough expressive power to support the whole possibility theory, an...

Multimedia digital data is highly redundant: successive video frames are very similar in a movie clip, most songs contain some repetitive patterns, etc. This property can consequently be exploited to successively replace each part of the signal with a similar one taken from another location in the same signal or with a combination of similar parts. Such an approach is all the more pertinent whe...