This paper describes and evaluates the design of four virtual controllers for use in rotating three-dimensional objects using the mouse. Three of four of these controllers are "new" in that they extend traditional direct manipulation techniques to a 3-D environment. User performance is compared during…
By the term data-oriented language, I mean a language whose main concern is in the structuring and handling of data. For contrast, procedure-oriented and process-oriented languages are mostly concerned with expressing algorithms and protocols. Other terms, such as the much abused object-oriented, can be used…
This paper describes a technique for implementing the sort of small databases that frequently occur in the design of operating systems and distributed systems. We take advantage of the existence of very large virtual memories, and quite large real memories, to make the technique feasible.…
Formal specifications of operating system interfaces can be a useful part of their documentation. We illustrate this by documenting the Threads synchronization primitives of the Taos operating system. We start with an informal description, present a way to formally specify interfaces in concurrent systems, give…
This correspondence presents a statistical analysis of frequency estimation using state-variable balancing for a single sinusoid in the presence of additive noise at high signal-to-noise ratios. The calculated variance is compared to the performance of the frequency estimation using linear prediction and the result is…
GRIP is a high-performance parallel machine designed to execute functional programs using supercombinator graph reduction. It uses a high-bandwidth bus to provide access to a large, distributed shared memory, using intelligent memory units and packet-switching protocols to increase the number of processors which the bus…
A new modeling technique for voiced speech is introduced. Salient features are detailed modeling of speech waveforms and the use of improved parameter estimation techniques. The ideas of pitch-synchronous analysis are extended to make two subintervals synchronous with regions of approximately closed and approximately open…
Privacy in secret-ballot elections has traditionally been attained by using a ballot box or voting booth to disassociate voters from ballots. Although such a system might achieve privacy, there is often little confidence in the accuracy of the announced tally. This thesis describes a practical…
In this paper I analyse lattice Yang-Mills theories with continuous time. After a short discussion of more conceptual questions, such as the existence of a Hamilton operator in the infinite volume limit, I study the phase diagram. The existence of a strong coupling/low temperature confinement…
When I joined DEC in 1985, they were the world leader in networking. Using their VMS operating system, I could type a simple copy command to a computer in California, specifying a file and machine name, to copy a file from a computer in Massachusetts.…
The purpose of this paper is to draw attention to existential fixed-point logic (EFPL). Among other things, we show the following. If a structure A satisfies an EFPL formula φ then A has a finite subset F such that every structure that coincides with A…
This article examines the direction in which knowledge bases are constructed for diagnosis and decision making When building an expert system, it is traditional to elicit knowledge from an expert in the direction in which the knowledge is to be applied, namely, from observable evidence…
