The dif"cult problems in the design of systems which facilitate interoperation and mediation among information sources and their consumers arise from the presence of semantic heterogeneity among the schemas and ontologies supporting the different services. The purpose of this paper is to develop a taxonomy of semantic heterogeneity, and to describe, taking the perspective of text databases, the conditions under which autonomy-respecting interoperation of different kinds are likely to be feasible. The main conclusion is that interoperation can be based on structured database technology only if the participating organizations communicate among themselves, otherwise the considerations underlying text databases dominate the technology used. 1.

this paper I briefly sketch recent work on meta-logical foundations that seems promising as a conceptual basis on which to achieve the goal of formal interoperability. Specificaly, I will briefly discuss:

. The problem of retrieving information from a collection of heterogeneous distributed databases has attracted a number of solutions. However, the task of integrating established database systems is complicated not only by the differences between the database systems themselves, but also by the differences in structure and semantics of the information contained within them. The problem is exacerbated when one needs to provide access to such a system for naive end-users. This paper is concerned with a Knowledge-Based Systems approach to solving this problem for clearly bounded situations, in which both the domain and the types of query are constrained. At the user interface, dialogue is conducted in terms of concepts with which the user is familiar, and these are then mapped into appropriate database queries. To achieve this a model for query decomposition and answer construction has been used. This model is based around the development of an Intensional Structure containing informatio...

Data Analysis Problems . . . . . 5 6.2 E-M Algorithm . . . . . . . . . . . . . . . 5 7 Current Model-Building Experiments 5 8 Conclusions 6 Abstract This paper is about analyzing a dataset that has been collected off and on for over a hundred years. This dataset records the geyser eruptions in Yellowstone National Park, and while it is not massive in the sense of terabytes or more, it makes up for that in anomalies: it is very heterogeneous, partly missing and somewhat erroneous (almost all data collection is by volunteers who trek out to the geyser basins and watch). It affords a very good (and very stringent) test of any data analysis method, because it has many different kinds of anomalies all concentrated in a small space. In many very large data sets, the anomalies are often simply ignorable, but they are decidedly not ignorable in this case. The purpose of the data collection and analysis project is to support models of the causal interconnections among the geysers and predictiv...