Providing Trusted Components to the Industry
The software industry stands on feet of clay. However carefully we may strive to build correct and reliable software, we have no way of guaranteeing the quality of the result. Building correct and reliable software depends on the quality of so much else, from the hardware and the operating system to the compiler and the runtime libraries. And any significant software system has so many details and components of its own that we can hardly expect to get everything right if we do it all by ourselves. We describe an ambitious but realistic project that combines the ideas of reuse and formality with other more pragmatic techniques. The goal is to provide the entire software industry with a powerful set of reusable components deserving a high degree of trust.

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: Library Design

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: Approaches to Portability

title: A Note on Computing Multiple Sums
abstract: 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: 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.

title: Prediction of Material Properties from Chemical Structures. The Clearing Temperature of Nematic Liquid Crystals Derived from Their Chemical Structures by Artificial Neural Networks
abstract: The prediction of properties of molecules just on the basis of their chemical structures is desirable to selectively make molecules that have the wanted properties, like biological activity, viscosity, or toxicity. Here, we present an example of a new way to predict a property from the chemical structure of a chemically heterogeneous class of compounds. The clearing temperatures of nematic liquid-crystalline phases of 17383 compounds were used to train neural networks to derive this material property directly from their chemical structure. The trained neural networks were subsequently tested with 4345 structural patterns of molecules unknown to the networks to assess their predictive value. The clearing temperatures were predicted by the best network with a standard deviation of 13 degrees.