clarke@utcsri.UUCP (Jim Clarke) (02/16/87)
(SF = Sandford Fleming Building, 10 King's College Road) (GB = Galbraith Building, 35 St. George Street) SUMMARY: Tuesday, February 24, 11 am, SF1101, John Mylopoulos: ``Knowledge Representation and Software Development" Tuesday, February 24, 3 pm, GB 120, Jiawei Han: ``Handling Redundancy in the Processing of Recursive Database Queries" Thursday, February 26, 11 am, GB220, Ozalp Babaoglu: ``On the Reliability of Fault-Tolerant Distributed Computing Systems" Thursday, February 26, 3 pm, GB220, Joel Friedman: ``On the Convergence of Newton's Method" -------------- COLLOQUIUM, Tuesday, February 24, 11 am, SF1101 Professor John Mylopoulos University of Toronto ``Knowledge Representation and Software Development" Requirements and design languages for software development are gen- erally accepted by now, but there is little agreement on the principles that ought to guide their definition and the features that they ought to support. The talk will overview research on this topic based on the prem- ise that software development can be viewed usefully as knowledge base con- struction. Focusing on interactive information systems, such as reservation or registration systems, we will review features of a design language (Taxis) and a requirements modelling language (CML) based on this premise. We will also report on work in progress to build a software development environment using these languages. A.I. SEMINAR, Tuesday, February 24, 3 pm, GB 120 Professor Jiawei Han Northwestern University ``Handling Redundancy in the Processing of Recursive Database Queries" SYSTEMS SEMINAR, Thursday, February 26, 11 am, GB220 Professor Ozalp Babaoglu Cornell University ``On the Reliability of Fault-Tolerant Distributed Computing Systems" The designer of a fault-tolerant distributed system faces numerous alternatives. Using a stochastic model of processor failure times, we investigate design choices such as replication level, protocol running time, randomized versus deterministic protocols, fault detection and authentication. We use the probability with which a system produces the correct output as our evaluation criterion. This contrasts with previous fault-tolerance results that guarantee correctness only if the percentage of faulty processors in the system can be bounded. Our results reveal some subtle and counterintuitive interactions between the design parameters and system reliability. THEORY SEMINAR, Thursday, February 26, 3 pm, GB220 Professor Joel Friedman University of California ``On the Convergence of Newton's Method" -- Jim Clarke -- Dept. of Computer Science, Univ. of Toronto, Canada M5S 1A4 (416) 978-4058 {allegra,cornell,decvax,linus,utzoo}!utcsri!clarke