In the Biodiversity World (BDW) project we have created a flexible and extensible Web services-based grid environment for biodiversity researchers to solve problems in biodiversity and analyse biodiversity patterns. In this environment, heterogeneous and globally distributed biodiversity-related resources such as data sets and analytical tools are made available to be accessed and assembled by users into workflows to perform complex scientific experiments. One such experiment is bioclimatic modelling of the geographical distribution of individual species using climate variables in order to predict past and future climate-related changes in species distribution. Data sources and analytical tools required for such analysis of species distribution are widely dispersed, available on heterogeneous platforms, present data in different formats and lack interoperability. The BDW system brings all these disparate units together so that the user can combine tools with little thought as to their availability, data formats and interoperability. We describe the architecture of the BDW problem solving environment (PSE) consisting of a number of components providing uniform access to heterogeneous resources and analytical tools. Architectural components of the BDW system include a workflow management tool, resource wrappers, a communications layer, BDW datatypes and a metadata repository.

In the GRAB (Grid and Biodiversity) project we are developing a prototype to illustrate some aspects of the GRID's potential for collaborative biodiversity research. A catalogue of life, two species information systems (SISs) and a climate database are made available in a problem solving environment that demonstrates how bioclimatic modelling can be performed by bringing together such resources. We use Globus to provide access to these resources, in a secure environment. We also discuss more generally the GRID's potential for biodiversity research, and identify the main areas of development within the GRID that are needed to support such research.

A principal problem with integrity constraints' use for monitoring dynamically changing database integrity is evaluation cost. This cost associated with performance of checking mechanisms is the main quantitative measure which must be supervised carefully. Based on literature, evaluating an integrity constraint cost includes these main components: (i) data amount accessed; (ii) data amount transferred across network; and (iii) number of sites involved. In distributed databases, where many networked sites are involved, not only amount of data accessed must be minimized but also amount of data transferred across network and number of sites involved. In [Ibrahim H, Gray WA, Fiddian NJ. SICSDD: Techniques and implementation. In Proceedings of Constraint Databases and Applications, Second International Workshop on Constraint Database Systems (CDB'97), Delphi, Greece, January 1997, pp 187–207], we introduced an integrity constraint subsystem for a relational distributed database. The subsystem consists of several techniques necessary for efficient constraint checking, particularly in a distributed environment where data distribution is transparent to application domain. Here, we show how these techniques effectively reduce constraint checking cost in such a distributed environment. This is done by analyzing and comparing generated simplified forms to respective initial constraints respecting amount of data to be accessed, amount of data transferred across network, and number of sites involved during evaluation of constraints or simplified forms. Generally, our strategy reduces data amount needing to be accessed since only fragments of relations subject to update are evaluated. Data amount transferred across network and number of sites that are involved are minimized by evaluating simplified forms at target site, i.e., site where update is performed. © 2001 John Wiley & Sons, Inc.

The authors demonstrate a prototype toolkit called ITSE (Integrated Translation Support Environment), for interoperation and migration of heterogeneous database systems.

Resolving different levels of heterogeneity present in heterogeneous database environments is a subject that has been addressed in a number of research projects. Graphical user interfaces are becoming the de-facto form of user interface in many application areas, including database management systems. The use of a popular visualisation notation to present schemas at an abstract level and to permit direct user manipulation of this visualisation in formulating queries is one of the most widespread approaches to providing database graphical user interfaces. The existence of a variety of visualisation notations (which are in common use to visualise schemas) introduces additional heterogeneity to a distributed system, in visual representation at the end-user interface level. This paper describes the use of meta-programming techniques which are applied to resolve this visual model heterogeneity on existing databases, by allowing a user to select a preferred visualisation notation, both to view the schema and to query the database.

Abstract An experimental software tool called FAST‐Fast Assembly Tool—has been used to evaluate the operational characteristics and range of application of the program translation technique known as meta‐assembly. It has been applied successfully in practice to a variety of different types of assembly problem and would appear to show some promise for the future in a microprocessor support context. The most significant aspects of the design, implementation and application of FAST are discussed.

In the context of this paper a computing software system consists of a database, an associated user interface which allows users to analyse the data and the routines or programs which implement the analytic functions available through the user interface. It is assumed that the complete system - source code and data - already exists in a form which is as easily portable as possible between different computer environments. For such systems adaptability is the problem of adjusting the user interface and analytic capabilities to suit different user communities when such a system is transferred from one environment to another. This may include adaptation to specific hardware facilities as well as user requirements.In 1977/8 the International Planned Parenthood Federation (IPPF) funded a project at University College Cardiff to implement a portable computing software system originating from the Population Dynamics Group (PDG) at the University of Illinois. This system allowed users to perform population projections under different demographic conditions showing in a graphical presentation how the population of a country varies over selected time spans. The database consisted of population statistics for a number of countries. When implemented at Cardiff it was intended that this system should be used as a demographic training aid by the post graduate diploma students in the David Owen Centre for Population Growth Studies. These students are an international group who are specialists in the field of demography but have little or no computing background.This paper will discuss briefly how this portable system was implemented on a PDP 11 minicomputer at Cardiff and then give a fuller description of the adaptation of the user interface and analytic capabilities to the local community and its computer facilities. General conclusions will be drawn as to how such systems should be written so as to ease the problems of adaptability.

In most general purpose computer systems there is a wide variety of software available to users. Such software is usually provided in one of three organisational forms - routines in a library; collections of related functions grouped in a package with a common interface; independent programs called through operating system commands. This interdependent tripartite structure creates problems for non-sophisticated users as it involves different levels of user interface complexity.At the routine level a user must write programs in an appropriate host programming language to use the software. If he wishes to use a selection of routines written in incompatible languages then he may have to familiarise himself with more than one host language. In each language he must be aware of the calling conventions for routines, the possible representations of various types of data, the methods of passing parameters and the ways of inputting and outputting data to and from the external environment. This type of interface occurs with libraries like NAG and IMSL.