Visual programming languages are emerging as an important paradigm for development of interactive multimedia presentations. We are actively developing and using such languages and have identified several criteria for evaluating the user interface for such tools. These criteria include: 1) support for the authoring process, 2) icon set semantics, and 3)… (More)
The security of a major operating system is investigated, including recently announced security enhancements. Four areas of security which are generally applicable to operating system design are discussed. File system security flaws were discovered, permitting a total system penetration. These flaws are described and improvements are recommended.
The chlorophyll synthase gene from oat (Avena sativa) was cloned and expressed in Escherichia coli. The deduced amino acid sequence consists of 378 amino acids including a presequence of 46 amino acids. Deletion mutants show that a core protein comprising amino acid residues 88 to 377 is enzymatically active. The sequence of the mature protein shows 85%… (More)
Over the past two years the Interactive Media Group has developed a variety of multimedia applications using various X11-based programming environments. These applications include: • Audio and video conferencing • Multimedia presentation authoring • Time-based document annotation (audio, graphics, text) • Meeting protocol analysis • Hypermedia browsing •… (More)
We have developed a set of interactive tools for collecting, annotating, and analyzing group communication sessions. These tools have been used to model group meetings which we have enacted on our computer-based video conferencing system as well as single location meetings. The purpose of this work is to support the analysis of group meetings over… (More)
The programming language POOL (Parallel Object Oriented Logic) allows computation to be represented as a collection of parallel objects which communicate via asynchronous message passing. Object procedures are Constraint Logic Programming (CLP) programs. POOL objects are mapped transparently to a network of CLP machines which execute concurrently. An… (More)
The prevailing vision for next generation multimedia communication systems is a digital one. However, we anticipate a transitional period in which hybrid networks involving both analog and digital technology will coexist. These analog facilities will include crossbar audio-video switches, CATV distribution systems, and dedicated lines. For some scale of… (More)
Next generation computer and communications technology for instructional environments is expected to accelerate progress in distributed and collaborative learning and interactive multimedia courseware. Various industry and international standards groups are currently creating specifications which will define a framework for how this technology will be… (More)