Peter M. D. Gray

KRAFT: knowledge fusion from distributed databases and knowledge bases

The KRAFT project aims to investigate how a distributed architecture can support the transformation and reuse of a particular class of knowledge, namely constraints, and to fuse this knowledge so as to gain added value, by using it for constraint solving or data retrieval.

Logic, algebra and databases

Inevitably, reading is one of the requirements to be undergone. To improve the performance and quality, someone needs to have something new every day. It will suggest you to have more inspirations, then. However, the needs of inspirations will make you searching for some sources. Even from the other people experience, internet, and many books. Books and internet are the recommended media to help you improving your quality and performance.

CoLan: a functional constraint language and its implementation

Abstract This paper is about the definition of CoLan, a high-level declarative Constraint Description Language, for use with an Object-Oriented Database (OODB). CoLan has features of both first-order logic and functional programming and is based on Daplex. CoLan expressions are translated into Prolog code that implements the operational semantics of the constraint. Pieces of generated code are cached inside the class descriptor of the ‘host’ class attached to appropriate slots. The pieces of code are retrieved along an inheritance path when an update on the database is attempted. If the update violates any of the retrieved constraints then it is rejected with an informative message. Thus constraints are expressed declaratively and they can even be retracted individually. However, they are implemented efficiently as code-generated methods, triggered selectively by an update. The implementation is described for the ADAM OODB, which uses meta-classes of the CoLan system to generate class descriptions.

A schema-based approach to building a bioinformatics database federation

Developments in our ability to integrate and analyse the data held in existing heterogeneous data resources can lead to an increase in our understanding of biological function at all levels. However, supporting ad-hoc queries across multiple data resources and correlating the data retrieved from these is still difficult. To address this, we are building a mediator based on the functional data model database, P/FDM, which integrates access to heterogeneous, distributed biological databases, while making use of existing search engines and indexes, without infringing on the autonomy of the underlying databases. Central to our design philosophy is the use of schemas. We have adopted a federated architecture with a five-level schema, arising from the use of the ANSI-SPARC three-level schema to describe both the existing autonomous data resources and the mediator itself. We describe the use of mapping functions and list comprehensions in query splitting, producing execution plans, code generation and result fusion. We give an example of cross-database querying involving data held locally in P/FDM systems and external data in the Sequence Retrieval System (SRS).

A Prolog Interface to a Functional Data Model Database

This paper describes a new database architecture for the manipulation of objects, based on an extended version of Prolog with modules. The modules permit the entity classes of the Functional Data Model to be viewed as Abstract Data Types to which methods stored in the modules can be applied. The database is stored as linked structures in a persistent heap. This architecture facilitates the use of Prolog as a navigational query language which can explore relationships in an object-oriented database.

An overview of the COBRA-ABS high level synthesis system for multi-FPGA systems

This paper presents an overview of the COBRA-ABS behavioural high-level synthesis tool. COBRA-ABS has been designed to synthesise custom architectures for arithmetic intensive algorithms, specified in C, for implementation on multi-FPGA Custom Computing Machine (FCCM) platforms. It performs globally optimising high level synthesis using simulated annealing, integrating all partitioning, scheduling, binding and allocation operations in one optimisation step, and has been designed to be retargetable to different board architectures. COBRA-ABS synthesises a custom Very Long Instruction Word (VLIW) architecture for the given algorithm for implementation on the specified FCCM. The paper gives details of the architectural issues which have influenced the design of the tool, looks at how it fits into the overall design flow and reviews the fundamental concepts and implementation of the globally optimising synthesis methodology. To illustrate the operation of the tool, a number of results for synthesis of a Fast Fourier Transform algorithm are presented.

Optimisation of methods in a navigational query language

In this paper we present the design of an optimiser for the object-oriented database P/FDM. We explore the approach of using a navigational query language, based on Shipmans original Daplex language [Sh 81] for the optimisation. The advantage of this is that it fits the navigational style of querying very well, but it is also optimisable. The optimisation is based on the equivalence of most Daplex queries to ZF-expressions as pointed out in [PG 90].

The Functional Approach to Data Management

point x-coord point -) num y-cood .. point -) num weight .. point -) num Suppose a particular application is much concerned with the distance between pairs of points. It would then clearly be useful to have a function to provide this directly as part of the user view. This can be achieved by including in the view specification the function definition dist point dist p1 p2 = point -> num; let x = (x-coord p1) let y = (y-coord p1) in sqrt (x*x+y*y);

Using the functional data model to integrate distributed biological data sources

There is unavoidable heterogeneity in the databanks and databases currently used for biological data collections. The authors are aiming to develop a system that will provide uniform access to heterogeneous databases via a single high-level query language or graphical interface and will enable multi-database queries. They have taken an approach in which high-level code in an object-oriented database system (based on the functional data model) is used effectively as a mediator between distributed heterogeneous databases. The resulting system enables one to ask queries that combine, for example, geometric calculations on three-dimensional protein structures stored locally and access to databanks held at the European Bioinformatics Institute, while making use of existing search engines and indexes when accessing remote data.

Compiling a Declarative High-Level Language for Semantic Integrity Constraints

The provision of more intelligent support for complex database applications is becoming an important research topic, and declaratively stated integrity constraints are increasingly being seen as a potential source of semantic information for such advanced DBMS’s. However, despite much research effort, the problem of efficiently compiling and checking a wide range of complex constraints has not yet been solved. And until it is solved, few database designers will be willing to sacrifice the performance of the every day database usage, in order to provide a complete semantic modelling of their application domain.