ef@phoibos.cs.kun.nl (E.D. Falkenberg) (09/26/90)
Ref. : EF/VB-496
Date : september 1990
ANNOUNCEMENT
At the Departement of Information Systems at the University of Nijmegen,
The Netherlands, a
POST - DOC RESEARCH POSITION
for the project
EVOLVING INFORMATION SYSTEMS
is to be filled.
Requirements: Phd; good kwowledge of information systems in general
and of time-related aspects of information systems in particular.
Duration: Fall 1990 - fall 1992
Applications: Until 15th October 1990 to
Prof.Dr. E.D. Falkenberg
Dept. of Information Systems
University of Nijmegen
Toernooiveld 1
NL 6525 ED NIJMEGEN
The Netherlands
PROJECT DESCRIPTION
'EVOLVING INFORMATION SYSTEMS'
In recent years various approaches to information systems have been developed
which deal with temporal aspects. One of these aspects is the ability of the
system, to store and retrieve not only current data, but also past,
"historical" data. In such systems, there is a "historical" or "conservative"
data base where not only a "snapshot" of the current set of data elements is
stored, but also the "lifetime" of the data elements, including proper "time
stamping". In these systems, this ability to deal with changes and the history
of a given universe of discourse is confined to the data elements. In practice
however, not only data elements change and have a history, but also laws and
rules of the universe of discourse (the conceptual schema). In addition
pre-defined operations and trigger mechanisms may also change and thus may
have a history. Changing the conceptual schema, as well as changing the
pre-defined operations and trigger mechanisms, means that basically a new
system must be implemented, which knows nothing about the changes at the
schema level. These changes are very time-consuming, expensive and maybe even
error-prone, since not only the schema etc. must be changed, but in general
the old data base, as well in order to maintain a consistent universe of
discourse specification.
This project is intended to go a significant step beyond the idea of
"historical" or "conservative" data bases. The project deals with the design,
specification and implementation of "Evolving Information Systems" (EIS).
These are systems with be ability to deal properly with changes at all the
mentioned levels; data elements, conceptual schema, pre-defined operations and
trigger mechanisms and their history. Thus, in an EIS the building and the
maintenance of the systems specification is a continuous process throughout
the lifetime of the system.
The aim of the project is to develop an adequate conceptual model and a
specification language for evolving universes of discourse and a prototype
implementation of a corresponding information system software package,
suitable for the realization of EIS. Furthermore, it is necessary to develop a
discipline for designing and maintaining EIS, and to perform case studies,
where significantly evolving information systems are be implemented, in order
to test the adequacy of the specification language, the design and maintenance
discipline, and the software package.
In this project, there are three major task areas to be covered:
a. The area of the conceptual model and the specification language. Special
aspects which are to be dealt with include: The time stamping of universe
of discourse elements, the handling of correction and roll-back of
specifications, and the specification of the "from-now-on"rules.
b. The area of the architecture and implementation of generalized EIS
software. Special aspects which are to be dealt with have include: The
architecture of a general message processor dealing with input and changes
of universe of discourse specification, the consistency checking, and data
base optimization aspects.
c. The area of the design and maintenance disipline, including the case
studies. A special aspect here is the integration of the initial design
and the further development and maintenance of the system specification
into one unified approach.