In this paper we first review the main results in the theory of schemata in Genetic Programming (GP) and summarise a new GP schema theory which is based on a new definition of schema. Then we study the creation, propagation and disruption of this new form of schemata in real runs, for standard crossover, one-point crossover and selection only. Finally, we discuss these results in the light our ...

Impact analysis is seen as an important technique for controlling the evolution of software systems. Numerous approaches have been proposed which aim to assess the impact of changes on many types of development artefacts. These techniques, although suitable for specific applications, contain inherent weaknesses, making them unsuitable for analysis of object database schemata. In this paper, we ...

This paper rst analyses the impact of variance on schema transmission. Working from an exact derivation of the expected variance in schema transmission, it derives and analyses the signal-to-noise ratio for schemata. The paper then presents short term schema transmission probability results that focus on newly created schemata in the population. The analysis reveals the relative dependencies be...

We propose an analytic approach to approximate the survival probabilities of schemata under multi-point crossover and obtain its closed form. It gives a convenient way to mathematically analyze the disruptiveness of multi-point crossover. Based on the approximation, we describe a geometric property of the survival probability under multi-point crossover and show the relationship between the sur...

In this paper, a generic system that generates parsers from parsing schemata is applied to the particular case of the XTAG English grammar. In order to be able to generate XTAG parsers, some transformations are made to the grammar, and TAG parsing schemata are extended with feature structure unification support and a simple tree filtering mechanism. The generated implementations allow us to stu...

In this article, we present a validation approach and method to support the development of database applications. We explain how validation can cope both with the need for a formalized evaluation of correctness as well as the need for prototyping of conceptual database schemata. We de ne di erent levels of correctness for such schemata and show how these levels can be achieved through validatio...

Approaches to morphology typically account for regular, completely productive aaxation, while ignoring subregular and semiproductive schemata. The alternative approach to derivational morphology presented here relates exceptions and subregularities to productive rules. It accounts for the contribution lexicalized words make to the rule, and for the fact that not all new formations follow thèrul...

We introduce two abstract, causal schemata used during causal learning. (1) Tolerance is when an effect diminishes over time, as an entity is repeatedly exposed to the cause (e.g., a person becoming tolerant to caffeine). (2) Sensitization is when an effect intensifies over time, as an entity is repeatedly exposed to the cause (e.g., an antidepressant becoming more effective through repeated us...

We construct models as an aid to our thought process. A particular class of models, operational models, can be used for simulation and prototyping. The Opj modeling language is suitable for building operational models of complex software systems. The notion of operational parameterized building block is the key point of the approach, which focuses on two major phases: domain modeling and system...