Summary of Objectives and Approach.
Detailed Summary of Technical Progress.
cc(FD) and NEWTON
constraint-based prototypes),
graphics support, and database tools (e.g., new indexing methods for
constraints, multidatabases, extensible optimization EPOQ, and the AQUA data
model). There has been significant progress on algorithmic methods, including
dynamic algorithms, approximation algorithms for combinatorial optimization,
parallel computing and hierarchical learning. A major accomplishment has been
a breakthrough linear-time algorithm for minimum spanning trees.
Our efforts in programming environments have concentrated on the evolution of a system for program visualization. We have developed a framework for providing a variety of 3D visualizations and a mapping language that allows arbitrary objects to be visualized. The prototype VALLEY is close to completion.
We have continued to work on trace-based debugging, porting our trace package AARD to Solaris and experimenting with various strategies to compact the trace data by several orders of magnitude to make the concept practical. We have been working on porting FIELD to Solaris to increase its compatibility with the native toolkit.
We have begun a new effort on fragment integration. The idea here is to provide the facilities associated with data integration in a programming environment, i.e. hypertext linking, intelligent editing, smart system rebuilding, without having to use a central repository.
In the last year we have continued to make significant progress on developing new debugging and programming tools for large, complex, parallel (and sequential) systems.
We have continued our work on the cc(FD) constraint language.
We have
developed new constraint languages for linear constraints and nonlinear
constraints (NEWTON).
We have developed new randomized, parallel and dynamic algorithms for approximation problems and for computational geometry problems.
We have developed a model for multi-grained parallelism that addresses the question of which architectures are best for problems that express both serial and parallel behavior.
We have studied algorithms for planning in very large stochastic domains and controlling partially observable Markov decision processes.
The Graphics Group continued research in new 3D user interface tools. Collaborating with research at NASA Ames, we have developed several 3D time-varying fluid-flow visualization tools: the streamline, particle path, ribbon, hedgehog, colorpicker, rake, and isosurface widgets. These tools will help scientists at NASA study fluid flows in a virtual-reality environment. We also developed a technique for annotating 3D time-varying data fields that lets scientists embed annotation markers in the same 3D space in which the flow data resides.
We are developing the Thread-Monitor Library, a system for monitoring Solaris-threads programs.
We continued our work on Interactions, an open, nested, flexible transaction model for multidatabases and the MONGREL Multidatabase System.
We also continued the design of an open, extensible query optimizer called EPOQ. As part of this effort, we have been exploring the extension of an object-oriented query algebra to include queries on lists and trees. We have completed an initial design of such a language in the context of the AQUA data model.
Transitions and DOD Interactions.
Software and Hardware Prototypes.
Considerable use is made by universities and research laboratories of the software prototypes developed through this (and its predecessor) ARPA efforts. The distribution of software has been centralized in the department and the responsible systems staff member is John Bazik jsb@cs.brown.edu 401-863-7624. Since June 1990 (when our accounting was put in place) there are the following statistics:
In addition there have been extensions to the prototype
cc(FD) constraint language and MONGREL multidatabase system
developed as part of this effort.
cc(FD)', in Intelligent Scheduling, Morgan Kaufman.
Invited and Contributed Presentations.
Honors, Prizes or Awards Received.
Project Personnel Promotions Obtained.