The Kestrel Interactive Development System (KIDS) provides automated sup- port for the development of correct and efficient programs from formal specifications.

Reusing the products of the software development process is an important way to reduce software costs and to make programmers and designers more efficient. Object-oriented programming permits the reuse of design as well as programs. This paper describes two techniques for reusing design and how these reusable designs are developed. Abstract classes are reusable designs for components while frameworks are reusable designs for entire applications or subsystems. These two techniques are related since frameworks almost always contain abstract classes. Although the most widely used frameworks are for user interfaces, this paper draws its examples from a framework for the virtual memory subsystem of an operating system.

The Kestrel Interactive Development System (KIDS) provides knowledge-based support for the derivation of correct and efficient programs from formal specifications. We trace the use of KIDS in deriving an algorithm for solving a problem arising from the design of sonar and radar signals. This derivation illustrates algorithm design, a generalized form of deductive inference, program simplification, finite differencing optimization, partial evaluation, case analysis, and data type refinement. All of the KIDS operations are automatic except the algorithm design tactics which presently require some interaction. Dozens of programs have been derived using the KIDS environment and we believe that it could be developed to the point where it can be used for routine programming.

. Requirements engineering (RE) is perceived as an area of growing importance. Due to the increasing effort spent for research in this area many contributions to solve different problems within RE exist. The purpose of this paper is to identify the main goals to be reached during the requirements engineering process in order to develop a framework for RE. This framework consists of the three dimensions: . the specification dimension . the representation dimension . the agreement dimension Looking at the RE research using this framework, the different approaches can be classified and therefore their interrelationships become much clearer. Additionally the framework offers a first step towards a common understanding of RE. + This work was supported by ESPRIT Basic Research Action 6353 (NATURE) which is concerned with Novel Approaches to Theories Underlying Requirements Engineering and by the state Nordrhein-Westfalen, Germany. 1 Introduction There is general agreement among softwa...

Frameworks are an object-oriented reuse technique that are widely used in industry but not discussed much by the software engineering research community. They are a way of reusing design that is part of the reason that some object-oriented developers are so productive. This paper compares and contrasts frameworks with other reuse techniques, and describes how to use them, how to evaluate them, and how to develop them. It describe the tradeoffs involved in using frameworks, including the costs and pitfalls, and when frameworks are appropriate.