A Note on Computing Multiple Sums
In a recent paper, 1 ~:method was given for computing multidimensional sums in FORTRAN in a particular case •. We show that the general problem of computing mUltidimensional sums is best expressed by a recursive definition which can then be translated into a programming language. The method is applied to an example optimization"problem. ' "

title: Showing Programs on a Screen
abstract: We present a strategy and algorithms for displaying a meaningful view of structured objects such as programs on a screen of limited size. The methods introduced here are language-independent; they were developed for the implementation of Cepage, a structural editor making full use of modern display technology. The algorithms are linear with respect to the number of nodes in the syntax tree. We use a formal model of the screen allocation, the ‘calculus of windows’, which makes it possible to reason about the display process at a proper level of abstraction. A systematic approach was followed, in which a number of ‘invariants’ and ‘attributes’ were defined before the actual construction of the algorithms and data structures, and served as a basis for their development; the paper describes the methodology used and includes a semi-formal correctness proof of the main algorithm, which involves mutually recursive procedures.

title: Approaches to Portability

title: The conceptual perspective [Object Technology]
abstract: bject technology is here to stay. For a while, after object-oriented ideas burst onto the software scene in the mid-eighties, we heard people say, “It’s just a fad and will go away like the others.” Not any more. The commitment of the big players is proof enough. Just mention your favorite household name in hardware or software; almost certainly it has defined an “all object” software policy (although one might quibble about how seriously they are doing it, how much is show and how much is reality). True, except for banking, networking, and other areas with particularly demanding requirements, the spread of 00 ideas is not as universal in the applications software community as in the core group of computer vendors and major software houses. But the move is irresistible, and very few software experts doubt that object technology is the way to go. Not since Dijkstra came up with structured programming around 1970 has any idea affected so deeply how we think about software.

title: Library Design

title: Design by Contract, Components and Debugging

title: Issues in practical application of an adaptive interface
abstract: The authors have been developing a prototype sys[em for installation in an operationat business environment. During the development, a number of issues have been encountered. These include: ● constraints arising from placing prototypes in operational environments . lack of guidelines for selecting types of adaptation ● difficulty determining adaptation criteria ● difficulty obtaining necessary data from users ● lack of guidelines for making information display decisions ● problems in testing ‘real world’ interfaces These issues are not readily solved with more sophisticated adaptation algorithms; rather. they point out the need for CO1Iect ing more information from attempts to bring intelligent interfaces to complex business environments.

title: Age group differences in world wide web navigation
abstract: In this study, we examined the effects of age and training on efficiency and preferences in a World Wide Web search activity. Older participants were able to complete most of the tasks, but took more steps to find the information than did younger adults. Factors in this inefficiency were patterns of returning to the home page and revisiting pages that had been seen before during a search. Interactive training improved efficiency and altered preferences. We discuss implications for training and design.

title: Design and evaluation of an adaptive icon toolbar
abstract: As information systems become increasingly important in many different domains, the potential to adapt them to individual users and their needs also becomes more important. Adaptive user interfaces offer many possible ways to adjust displays and improve procedures for a user's individual patterns of work. This paper describes an attempt to design an adaptive user interface in a computer environment familiar to many users. According to one classification of adaptive user interfaces, the adaptive bar described in this paper would be classified as a user-controlled self-adaptation system.At the user's convenience, the adaptive bar offers suggestions for adding or removing command icons, based on the frequency and probability of specific commands. It also implements these changes once the user has agreed to them. Beyond the adaptive bar, the general behavior of the whole user interface does not change, thereby allowing the user to maintain a clear general model of the system. This paper describes the decision-making algorithm implemented in the bar. It also describes the bar's self-adaptive behavior of displaying the frequency of each icon's use through the icon's size. Finally, we present some encouraging preliminary results of evaluations by users.