This paper is an introduction to natural language interfaces to databases (Nlidbs). A brief overview of the history of Nlidbs is first given. Some advantages and disadvantages of Nlidbs are then discussed, comparing Nlidbs to formal query languages, form-based interfaces, and graphical interfaces. An introduction to some of the linguistic problems Nlidbs have to confront follows, for the benefit of readers less familiar with computational linguistics. The discussion then moves on to Nlidb architectures, portability issues, restricted natural language input systems (including menu-based Nlidbs), and Nlidbs with reasoning capabilities. Some less explored areas of Nlidb research are then presented, namely database updates, meta-knowledge questions, temporal questions, and multi-modal Nlidbs. The paper ends with reflections on the current state of the art.

Over recent decades there has been a growing interest in the question of whether computer programs are capable of genuinely creative activity. Although this notion can be explored as a purely philosophical debate, an alternative perspective is to consider what aspects of the behaviour of a program might be noted or measured in order to arrive at an empirically supported judgement that creativity has occurred. We sketch out, in general abstract terms, what goes on when a potentially creative program is constructed and run, and list some of the relationships (for example, between input and output) which might contribute to a decision about creativity. Specifically, we list a number of criteria which might indicate interesting properties of a program's behaviour, from the perspective of possible creativity. We go on to review some ways in which these criteria have been applied to actual implementations, and some possible improvements to this way of assessing creativity.

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It is sometimes claimed that genetic algorithms using diploid representations will be more suitable for problems in which the environment changes from time to time, as the additional information stored in the double chromosome will ensure diversity, which in turn allows the system to respond more quickly and robustly to a change in the fitness function. We have tested various diploid algorithms, with and without mechanisms for dominance change, on non-stationary problems, and conclude that some form of dominance change is essential, as a diploid encoding is not enough in itself to allow flexible response to change. Moreover, a haploid method which randomly mutates chromosomes whose fitness has fallen sharply also performs well on these problems.

Riddles based on simple puns can be dassified according to the patterns of word, syllable or phrase similarity they depend upon. We have devised a formal model ofthe semantic and syntactic regularities underlying some of the simpler types of punning riddle. We have also implemented thispreliminary theory in a Computer program which can generate riddles from a lexicon containing general data about words andphrases; that is, the lexicon content is not customized to produce jokes. An informal, formative evaluation of the program's results by a set of human judges suggests that the riddles produced by this program are of comparable quality to those in general circulation among school children.