Christian Gram

Christian Gram
Dansk Datahistorisk Forening

MSc

About

24
Publications
4,234
Reads
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197
Citations
Citations since 2016
0 Research Items
43 Citations
2016201720182019202020212022024681012
2016201720182019202020212022024681012
2016201720182019202020212022024681012
2016201720182019202020212022024681012
Introduction
Skills and Expertise

Publications

Publications (24)
Conference Paper
Full-text available
In 1979 a software research and development centre was created to demonstrate the power of systematic and formal methods in software development. One of the first and biggest projects at Dansk Datamatik Center (DDC) was to develop an Ada compiler and run-time system. DDC made the first DoD validated Ada compiler in Europe, and the Ada project was c...
Conference Paper
Full-text available
Following a session on university education, this panel discussed early Nordic visions and experiences on university computing education, contrasting them to today’s needs and the international development at that time. This report gives short papers by the panelists (their opening statements), and a brief summary (the chair’s interpretation) of th...
Conference Paper
Full-text available
In this panel session, people from the four countries Finland, Sweden, Norway, and Denmark who participated in the early development of computers and computer industry discuss how the computer industry started and what happened 30 to 40 years ago. We will try to answer questions as follows. How and why did the computer development and industry star...
Chapter
The workshop discussed what to be understood by a formal design method, and what is required to make the formal methods useful and used in practice, i.e., in design of industrial scale interactive systems. It is proposed to arrange a rather detailed comparison of several methods on a selected test case.
Chapter
Every engineering project is driven by the need to produce an acceptable product which matches the users’ requirements and which will therefore be accepted in accordance with contractual obligations. Where a product is being produced speculatively in the hope of attracting users, there is just as strong a set of requirements (including costing and...
Chapter
Full-text available
This chapter demonstrates how one can use analysis of software architectures to generate software designs that are compatible with a chosen ‘property profile’. Such a profile must be determined during requirements specification. The approach used in this chapter is to take each external and internal property, and describe (in)compatibilities betwee...
Chapter
Full-text available
This chapter introduces a single large example of using the properties and architecture which have been discussed in earlier chapters. The example chosen is an Air Traffic Control (ATC) Support System. The concrete meaning of the abstract properties introduced in earlier chapters will be discussed in that context, showing how one property interacts...
Chapter
Full-text available
The usability of an interactive system is linked to the quality of the dialog, and quality shall here be expressed through a number of measurable properties of the dialog. The aim of this chapter is to identify and define a set of user-centered properties of interactive systems which promote high quality from the perspective of the users. The set m...
Chapter
Full-text available
An interactive system is seen by different people from different points of view. The system user is concerned with external properties, such as those that influence task coverage, flexibility and robustness during system use. The developer is often more concerned with those internal properties which address such things as the costs and reliability...
Book
IFIP's Working Group 2.7(13.4)* has, since its establishment in 1974, con­ centrated on the software problems of user interfaces. From its original interest in operating systems interfaces the group has gradually shifted em­ phasis towards the development of interactive systems. The group has orga­ nized a number of international working conference...
Article
Full-text available
An interactive system must be designed for usability. But usability is often described through a number of heuristics that are difficult to use directly in the design process. This paper relates the most important usability heuristics to software properties which the developer may design for. The software properties are grouped after influence on t...
Article
As a follow-up on John Karat's paper in a previous SIGCHI bulletin on IFIP's activities [Karat93], the present article describes another IFIP-activity of interest to the HCI community.
Conference Paper
The meaning of a program can be specified by pre- and postconditions, and the semantics of each statement can be defined by its weakest precondition. We present the development including implementation of a simple system to verify small programs. The system contains a weakest precondition calculator and a theorem prover; it is specified using VDM (...
Article
In computer science a number of mathematical disciplines are used: Programming language theory and automata theory use mathematical logic, formal systems, algebra, and recursive functions.The study of program structure and program verification uses graph theory as well as some of the above disciplines.The study of computability—'what can we compute...
Article
Two representations of zero in floating-point arithmetic are considered in relation to a summation with correction for rounding errors. The common representation with exponent zero is shown in this case to be better than the “academic” representation where the exponent depends on the “history” of the zero.
Book
Detailed programming Manual for the Danish computer Gier, developed 1959-61
Article
This paper gives a brief review of the design of the machine GIER (42-bit words, 1-k core store, 12-k drum store, 50-microsecond fixed point, 100-microsecond floating, add time) and its programming systems. The principal subjects are: The order structure, the operating system, the ALGOL 60 system, an evaluation of the order structure, the hardware...

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