Several agent platforms of general purpose exist — for example, Voyager, Jade, and Grasshopper — each of which provide an environment for building and executing software agents. Unfortunately, the platforms are usually incompatible with each other. Thus, agents built for one platform cannot be used in another platform, nor can they interact with agents in other platforms. Some effort is put int...

The design and operation of long-lived, sustainable systems (LSS) are hampered by limited support for change over time and limited preservation of system knowledge. The solution we propose is to adopt software product-line engineering (SPLE) techniques for use in single, critical systems with requirements for sustainability. We describe how four categories of change in a LSS can be usefully han...

Recent changes in software technology have opened new possibilities for statistical computing. Conditions for creating efficient and reliable extensible systems have been largely improved by programming languages and systems which provide dynamic loading and type-safety across module boundaries, even at run time. We introduce Voyager, an extensible data analysis system based on Oberon, which tr...

The Voyager 2 Planetary Radio Astronomy experiment to Jupiter has confirmed and extended to higher zenomagnetic latitudes results from the identical experiment carried by Voyager 1. The kilometric emissions discovered by Voyager 1 often extended to 1 megahertz or higher on Voyager 2 and often consisted of negatively or, less frequently, positively drifting narrowband bursts. On the basis of ten...

The Voyager 1 spacecraft is currently in the vicinity of the heliopause, which separates the heliosphere from the local interstellar medium. There has been a precipitous decrease in particles accelerated in the heliosphere and a substantial increase in galactic cosmic rays (GCRs). The evidence is unclear, however, as to whether Voyager 1 has crossed the heliopause into the local interstellar me...