Information-system structure by communication-technology concepts: A cybernetic model approach

摘要

Information-systems are classified into two types, termed “Evidence-of Existence” and “Presentation” of information. The objective of the evidence-type system lies in the domain of documentation and retrieval of information. The structure of this system-type is developed, with application of cybernetic concepts, as an isomorphic model in analogy to the system-structure of communication technology. The latter postulates three criteria of structuring: (1) Source-Channel-Sink, with input-output characteristics, (2) Filter-type communication-channel, (3) Reversable code. These criteria are applied to the structuring of information-systems of the evidence-of-existence type. For the purpose of two-way communication the information-systems have to be represented by closed-loop models. The selective-retrieval requirements necessitate the system-channel to be a filter of information. These information-filters are implemented by keyword-phrases, being identical with the codewords. They yield a uniquely decodable code which is totally reversible to adequately serve both the documentation and the retrieval of documents. It is proven that hierarchic information-systems, applying categorization or subject-heading objects of information, do not meet the mandatory code-requirements. The inherent coding-deficiencies of hierarchic systems generate intolerable retrieval ambiguities. The same critique applies to the thesaurus concept. The development of a novel species of thesaurus is suggested, realizing a kind of Linnéan encyclopedia of general human knowledge, presenting all relevant interrelations of objects of knowledge. Such thesaurus would provide the much needed support for formulating efficient search queries. Other relevant features of communication technology, like the information-potential, should be isomorphically transformed into information-system models.