Electronic `how things work' articles: two early prototypes

The electronic encyclopedia exploratorium (E³) is a vision of a future computer system-an electronic book describing how thing work. Typical articles in E³ will describe such mechanisms as compression refrigerators, engines, telescopes, and mechanical linkages. Each article will provide simulations, three-dimensional animated graphics that the user can manipulate, laboratory areas that allow a user to modify the device or experiment with related artifacts, and a facility for asking questions and receiving customized, computer-generated English-language explanations. Some of the foundational technology is discussed, focusing on topics in artificial intelligence, graphics, and user interfaces. The initial prototype system and the technical lessons learned from it, as well as the second prototype currently under construction, are described     

Software, Software Engineering and Software Engineering Research: Some Unconventional Thoughts

Software engineering is broadly discussed as falling far short of expectations. Data and examples are used to justify how software itself is often poor, how the engineering of software leaves much to be desired, and how research in software engineering has not made enough progress to help overcome these weaknesses. However, these data and examples are presented and interpreted in ways that are arguably imbalanced. This imbalance, usually taken at face value, may be distracting the field from making significant progress towards improving the effective engineering of software, a goal the entire community shares. Research dichotomies, which tend to pit one approach against another, often subtly hint that there is a best way to engineer software or a best way to perform research on software. This, too, may be distracting the field from important classes of progress.     

Hydrogen transport by group 5 metals: Achieving the maximal flux density through a vanadium membrane

Hydrogen transport by 100-μm-thick vanadium and palladium membranes was studied in the pressure range from 1 × 10^?8 to 4.5 × 10^?1 MPa at a temperature of 400°C. Both sides of the vanadium membrane were covered by 2 μm of palladium (Pd-V-Pd) for facilitating the dissociative absorption and associative desorption of H₂ molecules. At low pressures, hydrogen flux densities through vanadium and palladium membranes are nearly the same; at high pressures, the flux through the vanadium membrane becomes 16 times larger than the flux through the palladium membrane and attains a value of 2.4 scc cm^?2 s^?1. This flux of permeating hydrogen is larger than all values ever observed earlier for membranes made of group 5 metals or any other unsupported metal membranes.     

Reconstruction of distributed physical fields in integrating measuring systems and systems of direct measuring in rare points of field

The theoretical analysis of reconstruction problem of distributed physical fields in integrating measuring systems has been carried out. The integrating measuring systems are compared with the systems of direct measuring in rare points of the field. And the application prospects have been revealed. The text was submitted by the authors in English.     

Using tool abstraction to compose systems

The tool abstraction paradigm, which supports the evolution of large-scale software systems by easing design changes in the system functions, is discussed. Systems that support tool abstraction are structured as a pool of abstract data structures shared by a collection of cooperating `toolies', where each toolie provides a piece of the overall system function. When one toolie updates the shared data, other toolies must be notified: otherwise, cooperating-but-independent toolies may not execute, and the overall system function may be compromised. The KWIC (key word in context) index production system is used to illustrate the idea of tool abstraction. The relationship of tool abstraction to other concepts is examined     

Towards a Formal Treatment of Implicit Invocation Using Rely/Guarantee Reasoning

Implicit invocation [SuN92, GaN91] has become an important architectural style for large-scale system design and evolution. This paper addresses the lack of specification and verification formalisms for such systems. A formal computational model for implicit invocation is presented. We develop a verification framework for implicit invocation that is based on Jones' rely/guarantee reasoning for concurrent systems [Jon83, St?91]. The application of the framework is illustrated with several examples. The merits and limitations of the rely/guarantee paradigm in the context of implicit invocation systems are also discussed. Received August 1997 / Accepted in revised form June 1998