Showing papers on "Semantic interoperability published in 1986"

Semantic networks as abstract data types

Abstract: ion has often been used to permit one to concentrate on the relevant attributes of the domain and to disregard the irrelevant ones. This is accompanied by a reduction in the complexity of the domain. Researchers have extensively studied the use of abstraction in programming languages to allow programmers to develop software that is precise, reliable, readable, and maintainable. In spite of the amount of research that it has been subjected to, data abstraction has been largely neglected by programmers, when compared with other abstract methodologies used in programming. One problem is that it is not always easy to characterize the correct set of operations that defines an abstract data type; and, although many definitions have been presented, no precise methodology has ever been proposed to hint at the choice of those operations. A second problem is that there is a discrepancy between the formalism used to define an abstract specification and the architecture of the underlying virtual machine used to implement it. This discrepancy makes it difficult for the programmer to map the abstract specification, written at design time, into a concrete implementation, written at coding time. In order to correct these problems, a theory of data abstraction is presented, which includes a new definition of abstract data type and a methodology to create abstract data types. Because of their complexity, semantic networks are defined in terms of a variety of interrelated data types. The preciseness of the abstract data type formalism, and its emphasis on the behavior of the data type operations, rather than on the structure of its objects, makes the semantics of semantic networks clearer. In addition, the design, development, and maintenance of a semantic network processing system requires an appropriate software engineering environment. The methodology of data abstraction, with its philosophy of modularity and independence of representations, provides this kind of environment. On the other hand, the definition of a semantic network as an abstract data type and its implementation using the methodology of data abstraction provide insights on the development of a new theory of abstract data types and the opportunity for testing and refining that theory. (Abstract shortened with permission of author.)

Designing Equvialent Semantic Models for Process Creation

Abstract: 1 I n t r o d u c t i o n Process creat ion is an impor tant programming concept which appears in a variety of forms in many contemporary programming styles. In imperat ive programming one finds process creation in languages such as Ada [Ad], NIL [SS] and many others. In the context of functional or dataflow languages we refer to [BrB] for a semantic study. For logic programming many recent references can be found in [Sa]. Object-oriented pi-ogramming has the family of actor languages (see, e.g., [He,C1,Agl) as examples. The present s tudy was inspired by the language POOL, an acronym for Parallel Object -Oriented Language, described in IAml,Am2]. In two previous investigations we have developed operational (0) and denotationat (P) semantics for P O O L [ABKR1,ABKR2 I. These two semantic models were designed independently of each other, and the investigation reported below const, itutes the first step towards the goat of settling the relat ionship between the two models. For this purpose we concentrate on the programming notion of process creation together with a simple version of process communication, and leave a number of further key notions in P O O L for later study. More, specifically, we treat communication in the sense approximately as exemplified by CSP [Hol,Ho2] and do not treat message Most of this work has been carried out in the context of ESPRIT project 415: "Parallel Architectures and Languages for Advanced Information Processing A VLSI-directed Approach"