Browsing by Author "MacDonald, Bruce"
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Item Open Access EXPERT CONTROL FOR A ROBOT BODY(1987-12-01) MacDonald, Bruce; Andreae, John H.Mobile robots with dextrous hands and sophisticated sensory systems will require intelligent, knowledge-based, expert controllers. In this paper we develop a design for a robot controller which can acquire task knowledge as it interacts in the world with its human users. The design is based on four reasonable assumptions which lead us to a theoretical framework for robot learning systems. The framework is called a multiple context learning system. It is a production system with multiple templates for forming productions as the system interacts with the world. The paper discusses elaborations of the framework and experimental tests of the system.Item Open Access THE FDDI PILOT PROJECT IN COMPUTER SCIENCE AT THE UNIVERSITY OF CALGARY(1991-03-01) Hankinson, David; Rokne, Jon; Snowcroft, Brian; MacDonald, BruceContinued demands on the Computer Science Department's resources forced an unsatisfactory network topology. Sun Microsystem's implementation of FDDI was selected to replace the backbone, and is the first such installation in Western Canada. The paper reviews the hardware, software and topology of FDDI systems, explains the configuration chosen for the department, and discusses the installation. Each ring node requires a VME bus FDDI controller board. Physically the ring is star connected, providing convenient patch panel reconfiguration for maintenance and testing. All department file/client servers were attached to the ring, while groups of client workstations are controlled over sub-Ethernets. The resulting topology is a central backbone ring, with sub-Ethernets radiating from each FDDI node. FDDI's simplicity enables performance improvements in addition to the increased speed, so long as the network topology and systems configuration are carefully designed. Reliability is achieved by duplication of file systems on all ring nodes, so that any subnetwork may operate independently of the ring. We conclude by recommending that machine crashes should cause the FDDI board to pass through the data, rather than wrapping the dual rings and possibly causing unnecessary ring fragmentation. The paper discusses the relative merits of concentrators and optical bypass switches for fragmentation protection.Item Open Access INDUCING FUNCTIONS IN ROBOT DOMAINS(1988-01-01) Pauli, David; MacDonald, BruceThis paper describes a reimplementation of a function induction algorithm that is part of Peter Andreae's robot procedure learning system NODDY. Results are given, the implementation is compared to Andreae's version, and the BACON and COPER systems are compared to both. The discussion focuses on the representation of knowledge--in particular on the representation of inverse operators and the induced expression--and the strength of argument typing.Item Open Access OPTIMAL TUNNELING: A HEURISTIC FOR LEARNING MACROS(1993-03-01) James, Mark; MacDonald, BruceThis paper presents the Optimal Tunneling heuristic for learning macro operators. Optimal Tunneling produces shorter more useful macros than the similar Minimum to Minimum heuristic presented by Iba. Optimal Tunneling is arguably an improvement since its macros (a) best reduce search cost, (b) give the most accurate modification to the search space to make the heuristic function correct, and (c) result in better performance on comparative tests. Optimal Tunneling creates macros that cross exactly the expensive segment of the heuristic function along the current solution path. A water pouring analogy is proposed to illustrate the effect of macros on the cost of search in problem solving.Item Open Access PROCEEDINGS OF THE MACHINE LEARNING WORKSHOP AT AI/GI/VI'94(1994-05-01) MacDonald, Bruce; Holte, Robert; Ling, CharlesNo abstractItem Open Access STATE OF THE ART IN COMPUTER GRAPHICS AND ANIMATION(1987-03-01) Wyvill, Brian; MacDonald, BruceDuring the last ten years computer graphics has graduated from the laboratory into the public domain. In the last five years the computer animation industry has reached the hundred million dollar mark and is still growing. Presented here are some of the more important recent developments in computer graphics that have made this growth possible and how these advances benefit the simulation community.