https://ir.unisa.ac.za/handle/10500/24187 2026-05-06T12:53:49Z 2026-05-06T12:53:49Z Van der Vegte, L.J. https://ir.unisa.ac.za/handle/10500/24200 2018-06-01T01:00:53Z 1987-01-01T00:00:00Z

The development of a syntax checker for LOTOS Van der Vegte, L.J. In this article a brief overview is given of specification techniques in general and in particular, specification techniques used for the specification of communication protocols. This discussion forms the background against which the development of a syntax checker for LOTOS, LOTOSCHECK, was done. LOTOS is a specification technique which was developed during 1981-1984 for the specification of communication protocols. Development tools such as LOTOSCHECK are required in order to eventually semi-automate the lengthy and complex task of implementing and verifying a protocol. In the first section of the article the concept of a specification is discussed in general. In Section 2 the increasing interest in specification techniques in the area of data communications is discussed. In this section, reference is made to some of the formal description techniques for protocol specification which are currently being developed. LOTOS is introduced as one of these techniques which is currently receiving a lot of attention. An overview of LOTOS will be given in Section 3. This section will give a brief introduction to LOTOS and describe some of the more interesting characteristics of LOTOS. In Section 4 the actual development of LOTOSCHECK is discussed. The parsing technique which was used will be discussed in particular. The article concludes with references to other work already done in the area of semi-automated implementations of communication protocols. 1.

1987-01-01T00:00:00Z Roos, Jan https://ir.unisa.ac.za/handle/10500/24199 2018-06-01T01:00:59Z 1987-01-01T00:00:00Z

The protocol specification language ESTELLE Roos, Jan ESTELLE is being developed by the International Standards Organisation (ISO), Technical Committee (TC) 97, Sub-committee (SC) 21, Working Group (WG) 1, Formal Definition Technique (FDT) Subgroup B to fulfil the need for a protocol specification language. FDT Subgroup C is working on LOTOS as an alternative protocol specification language and the International Telegraph and Telephone Consultative Committee (CCITT) has developed SDL for the same purpose. The purpose of this paper is to briefly introduce the language ESTELLE and to discuss the following: - The characteristics of the language. • The finite state machine orientation of the language. • The formal semantics of the language constructs. • The levels of abstraction provided by the language. • Features enhancing protocol specification and verification. - The current level of maturity of the language. Some indications of the limitations of the language are given and the appendix contains a very simple skeleton example of an ESTELLE specification.

1987-01-01T00:00:00Z Podevyn, D. https://ir.unisa.ac.za/handle/10500/24198 2018-06-01T01:00:59Z 1987-01-01T00:00:00Z

Decision tables as a knowledge representation formalism Podevyn, D. A knowledge engineering tool called GESS (General Expert System Shell) is presented which is used for building different types of expert systems. Knowledge representation is based on direct extensions of the idea of decision tables. It was found that this formalism reduces the knowledge acquisition bottleneck by assisting the knowledge engineer in the structuring of knowledge because it enforces completeness and allows for automated checking of contradictions and redundancies. It was also found that this formalism is quite flexible in expressing knowledge and implementing different reasoning paradigms as is discussed in this paper. Complex systems have been built with Gess using its capability of creating networks of decision tables and the accessibilty of the external computer environment from within Gess.

1987-01-01T00:00:00Z Pirow, Peter Cluver https://ir.unisa.ac.za/handle/10500/24197 2018-06-01T01:01:02Z 1987-01-01T00:00:00Z

Research computeracy Pirow, Peter Cluver This paper describes the concept of computeracy as it applies to research workers and argues that research will be improved if the level of computeracy can be raised.

1987-01-01T00:00:00Z