Data types, abstract

Abstract Data Types In The Construction Of Knowledge-Based Quantum Chemistry Software... 

Recently, Diercksen and Hall (1) presented the OpenMol Program a proposal for an open, flexible and intelligent software system for performing quantum chemical computations. Central to their proposal was the observation that there is a close relationship between an abstract data type operation and a production rule in a rule-based expert system. The aim of this paper is to explore the establishment of a sound theoretical foundation for this relationship. 

Abstract data types have been established in computer science for many years (2). Indeed they are at the heart of the object-oriented programming paradigm. However, their use in scientific programming has been limited -probably because, prior to FORTRAN 90, FORTRAN provided no direct... 

Note that many features of a chemical database system could not be reasonably duplicated with a commercial DBMS. One reason was that general DBMS s were designed to treat numbers, text, dates and money data types, but not abstract data types such as chemical structures. This allowed DBMS vendors to tune the performance of their product to the needs of the general business community, a vast market place, and to avoid specialisation in narrower markets such as the chemical/pharmaceutical industry. 

The conceptual need for abstract data types emerged quickly in our experimentation with DDD. We looked first to Haynes s Infer system (Haynes 1993) as potentially supporting types in way that was compatible with contemporary programming methods research based in Scheme. Infer is an ML-style type inference system superimposed on the Scheme user level. It supports,... 

DDD provides a collection of transformations to replace an abstract data type occurance with a more concrete representation. Incorporating a representation requires defining a correspondence between terms in the abstract ADT and combinators in the concrete ADT. DDD assumes that a given representation has been verified, that is, that an implementation relationship has been established between the two ADTs. We usually work with a simple notion of implementation, involving a partial equivalence relation on the (term algebra of) the concrete type which supports the equational theory of the abstract type. 

Behavioral style All common procedural programming language constructs and abstract data types are supported the design is expressed as a set concurrent processes. This style has very poor performance for synthesis. 

Write up (04) Abstract data type (ADTyidentify DS ormulate problem (2) a... 

In the design phase, the students are expected to show the identified 2D/3D objects, data structures, and definition of ADT (Abstract Data Type). 

The architecture of the software refers to its organization into modnles. These modules include processes, abstract data types, communication paths, data stmcmres and display templates. There are munerous methods of dividing the software into modules with differing emphasis on particular kinds of module. The choice of architecture is very important in determining the simplicity of the modnles and of the interactions between them, which in timi determines the simplicity of their specifications and of the verification and validation tasks. 

A specification language should offer abstract data-types, so that specifications do not bias the algorithm design or implementation processes. However, abstract datatypes and the issue of their reification are not addressed anywhere in this book. 

Historically, mathematics has been the main, if not the only, science of representation , so it is not surprising that the lack of appreciation of the role of object representation has been inherited from mathematics, where the centuries-old tradition has been to represent objects as unstructured points . In this sense, the underestimation of the role of object representation in a computational model is also not surprising. But while the mainstream mathematics—Shaving been isolated from the problems arising in computer science—had no apparent impetus to proceed with the necessary radical developments, computer science has no such excuse. The concepts of data structure and abstract data type have been screaming for such fundamental developments. As was mentioned in Introduction, I believe the reasons for the lack of such developments within computer science have to do with its historical roots in mathematical logic, whose development was not at all motivated by the representation of physical objects... 

The abstract data type ImageG is introduced to represent an arbitrary shaped region with associated integer grey-scale values. ... 

On the data structuring level the method for defining semantics is borrowed from the concepts of abstract data types the effect of elementary operations on the data structure (creation, deletion, identification, navigation) is used. 

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