wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (04/28/89)
DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S ESSAY PRESENTATION -Tuesday, May 2, 1989 Mr. Guno Sutiono, graduate student, Dept. of Computer Science, University of Waterloo, will speak on "A Region-Based Approach for Digital Cel Painting." TIME: 3:30 PM ROOM: DC 1304 ABSTRACT Recently, a number of computer- aided paint systems have been developed to improve the colour painting process, traditionally one of the most time-consuming steps in 2-D cel animation production. However, much improvement remains to be made in the design of these new systems. In this talk, we describe a region-based cel painting design which uses the "paint-by-number" method and is based on a virtual frame buffer model. In this region-based design, the regions are recognizable, defined entities. This allows us to define functions for conceptually-based, interactive painting techniques, which can be easily implemented. Furthermore, the availability of this additional region information introduces the possibility of automatic multi-frame colour tracking, which can be implemented by transforming this problem into a well-known maximum matching problem in graph theory. Thus, this new region-based design builds upon techniques used in earlier systems and paves the way for future improvements.
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (06/15/89)
DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Monday, June 19, 1989 Denise M. Woit, graduate student, Dept. of Computer Science, University of Waterloo, will speak on "Rational Testing for Computational Geometry Codes: A Case Study TIME: 2:30 p.m. ROOM: DC 3540 ABSTRACT As the role of software grows in our society, the need for reliable and practical software testing techniques increases. Functional testing is one method that may help fulfill this need. While many functional testing techniques have been theorized, they are often too involved or too complicated to be of practical use. As well as the general testing technique, the testing process must also be of practical use: the testing environment should be engineered so that the tests will execute with minimal human interaction and be easily repeatable. In the area of computational geometry, algorithms are sometimes found to be intricate and counter-intuitive; these algorithms, especially, are in need of software testing techniques which are reliable, yet practical. One such algorithm is that of the visibility polygon problem. The fundamentals of a visibility polygon algorithm, VISPOL, are presented; a functional testing technique and environment are proposed which, while specific to VISPOL, can be extended into a general methodology for the testing of computational geometry codes; an account of the design and implementation of the VISPOL algorithm, using current software engineering practices, is given; and, the results of the proposed testing technique and environment applied to the VISPOL implementation are presented and analyzed.
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (07/28/89)
Dept. of Computer Science, will speak on ``Performance Studies in Optical Disk Storage.'' DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Thursday, August 3, 1989 Mr. K. Hatzilemonias, graduate student, Dept. of Computer Science, will speak on ``Performance Studies in Optical Disk Storage.'' TIME: 1:00 p.m. ROOM: DC 1302 ABSTRACT Optical disks, due to the low storage cost per bit of stored information, easy replication, large storage capacity, and long archival life, are projected to be the dominant storage technology for many storage intensive applications. In the research presented we investigate the various types of available optical disk storage systems and through experimentation we identify their performance characteristics. Based on the experimental results, mathematical models capturing the behavior of these systems have been developed and validated against the actual systems they represent. These models are incorporated in the implementation of simulators for various optical disk storage systems. We investigate the effects of a new notion of blocking and we show that in certain application environments, it can improve the retrieval performance of optical disk storage systems. Optical disk storage media is new and not well understood. The research presented provides answers and new insights about the various optical disk storage architectures and models their access performance.
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (07/28/89)
Dept. of Computer Science, will speak on ``Software Portability by Virtual Machine Emulation.'' DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Wednesday, August 2, 1989 Mr. Stefan Vorhoetter, graduate student, Dept. of Computer Science, will speak on ``Software Portability by Virtual Machine Emulation.'' TIME: 3:30 p.m. ROOM: DC 1304 ABSTRACT The proliferation of diverse computer architectures has resulted in an increased need for portable software, but many portability techniques incur a performance penalty. This penalty can be reduced by restricting the range of architectures to which a program must be portable, at the risk of limiting portability to new hardware as it becomes available. In this thesis we examine a technique for making a program portable to architectures for which it was not intended, without affecting its performance on other architectures. The technique used is virtual machine emulation, whereby an ideal (for the program) architecture is emulated by another program on an incompatible system. By designing the virtual machine carefully, performance loss due to emulation can be minimized, and the program to be ported can be recompiled for the virtual machine without modification.
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (08/11/89)
Dept. of Computer Science, will speak on ``Tuples in Imperative Programming Languages.'' DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Friday, August 18, 1989 Mr. David Till, graduate student, Dept. of Computer Science will speak on ``Tuples in Imperative Programming Languages.'' TIME: 2:00 p.m. ROOM: DC 3540 ABSTRACT Ordered lists of heterogeneous elements, known as tuples, appear in most imperative programming languages, usually as parameter lists for routine invocations or as subscript lists for array element extraction. In this talk, other tuple contexts are developed, and three constructs relating to them are discussed: the multiple assignment statement, multiple return values from routines, and input parameters passed by means of the assignment statement. The programming language K-W C, which implements most of these tuple contexts and constructs, is introduced and described.
daemon@watdragon.waterloo.edu (Owner of Many System Processes) (09/06/89)
Dept. of Computer Science, will speak on ``Study of Monitors.'' From: wlrush@poppy.waterloo.edu (Wenchantress Wench Wendall) Path: poppy!wlrush DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Friday, September 8, 1989 Mr. Michel Fortier, graduate student, Dept. of Computer Science, will speak on ``Study of Monitors.'' TIME: 2:00 p.m. ROOM: DC 1304 In the design of a concurrent system, problems of synchronization and communication of processes can be solve by using monitors. Over the past 15 years several different kinds of monitors have been investigated. A taxonomy is presented that encompasses all these traditional monitors and suggests others not found in the literature or in existing programming languages. The classification scheme is based on a single criterion - the scheduling of processes waiting to use the monitor which occurs after a wait, after a signal and at the exit of the monitor. It identifies a total of nine different primitive monitor types: six signal monitors based on categorizations of blocking/nonblocking signal and priority of resumption, two based on immediate return signal and priority of resumption, and two based on an automatic- signal mechanism and priority of resumption. An attempt is made to give some empirical discussion and analytical results about the classification criterion that suggest that some monitor types, although functionally equivalent, are better than other types. In particular, the priority-nonblocking monitor has properties that suggest it is better than the others. All the monitor types have been implemented in C language. By having the different monitor types in one language, it was possible to run tests to compare them. An animation facility has been implemented to visualize the different types of monitors by showing process movement on entry queues, on condition variables and in and out of the monitor. With this tool, it is possible to see the differences in the monnitors as well as deadlock and bottlenecks.
daemon@watdragon.waterloo.edu (Owner of Many System Processes) (09/07/89)
Dept. of Computer Science, will speak on ``A Model for Approximate Text Matching.'' From: wlrush@poppy.waterloo.edu (Wenchantress Wench Wendall) Path: poppy!wlrush DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Monday, September 11, 1989 Mr. George Townsend, graduate student, Dept. of Computer Science, will speak on ``A Model For Approximate Text Matching.'' TIME: 3:30 p.m. ROOM: DC 1302 ABSTRACT This thesis introduces the concept of Approximate Text Matching, a natural extension of approximate string matching. A hierarchical model is presented upon which solutions to this problem may be based. Traditional approaches to approximate string matching deal with transformations which, when applied at the string layer, cause two strings to become equivalent at the character layer. If the transformations required to achieve this are "reasonable" as determined by some heuristics, the two original strings are claimed to be approximately equal. This traditional model consists of two layers, the string layer and the character layer, where the string layer is viewed as a sequence of characters. The typical transformations applied to the string layer are transposition of characters, removal of superfluous characters, and addition of missing characters. In the model presented here, these same notions are applied at multiple layers of the problem. "Text" is viewed as a sequence of "fields of data", or phrases. A "field of data" is viewed as a sequence of "unit strings" or words. Each "unit string" is viewed, in the traditional manner, as a sequence of characters. The traditional transformations considered in approximate string matching are applied at each of these layers in a general way. The advantages of the model are twofold. First, the model understands the structure of the data, and will therefore search for matches for a particular field in an appropriate place. Secondly, the failure of the model at one layer is often compensated for at the next highest layer. The Oxford English Dictionary was used as a testing ground for algorithms based upon this model. Citations occurring in the body were matched against their sources in the O.E.D. bibliography. On two samples of data, correct matches were made over 90% of the time.
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (09/22/89)
Dept. of Computer Science, will speak on ``The Automatic Inbetweening of Keyframes Composed of Spline Curves Satisfying Various Constraints.'' DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Thursday, September 28, 1989 Mr. Ronald Hardock, graduate student, Dept. of Computer Science, will speak on ``The Automatic Inbetweening of Keyframes Composed of Spline Curves Satisfying Various Constraints.'' TIME: 2:30 p.m. ROOM: DC 1304 ABSTRACT This thesis presents a method one can use to obey a certain class of constraints between spline curves in a keyframe inbetweening environment. The general problem is ensuring that constraints, which are true for keyframes, will also be true for the computer-generated inbetween frames. Various types of constraints are outlined. A set of conditions on the interpolation method are outlined such that linear mapping constraints can be obeyed. Mention is also made of various constraints that are not expressible as linear mappings, to point to directions of future research.
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (09/28/89)
Dept. of Computer Science, will speak on ``Hypermedia Document Information Based Retrieval Applications.'' DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Thursday, October 5, 1989 Suzanne M. Potvin, graduate student, Dept. of Computer Science, will speak on ``Hypermedia Document Information Based Retrieval Application.'' TIME: 10:30 p.m. ROOM: DC 3540 ABSTRACT Hypermedia systems emphasize text and graphical information and provide interactive interfaces for browsing and editing information concepts. However, most hypermedia systems do not provide adequate query mechanisms. In this presentation, we present a specification and a prototype implementation of a hypermedia document-based information retrieval application (HyDIRA). This application combines the advantages of both hypertext and document management systems, and minimizes disadvantages related to present hypertext systems. The prototype version that has been implemented demonstrates the feasibility of the goals and functionality provided by HyDIRA. The document model used resembles the ODA/ODIF object- oriented standard for Office Document Architectures (although it is limited). We will present some first feedback on how the ODA/ODIF standard could be extended to support hypertext/hypermedia applications in an integrated and uniform manner.
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (10/12/89)
will speak on ``An Evaluation of Tension within an Extensible Spline Testing Facility.'' DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Monday, October 16, 1989 NOTE!! DATE CHANGE!! Mr. Paul Ruest, graduate student, Dept. of Computer Science, will speak on ``An Evaluation of Tension within an Extensible Spline Testing Facility.'' TIME: 10:30 a.m. ROOM: DC 3540 NOTE!! CHANGE OF ROOM ABSTRACT Beta2 and rational B-splines have received a great deal of attention in recent years. Both associate an extra parameter called tension with each control vertex which allows the curve to be pulled or pushed locally, relative to the control polygon, and independent of control vertex movement. An obvious question from the design point of view is whether users actually find these tension parameters useful. Therefore an experiment was designed and performed to explore the usefulness of tension when interactively designing curves. The experiment was performed on a reworked version of an extensible spline testing software system that has been developed at the University of Waterloo Graphics lab. October 5, 1989
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (11/17/89)
DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Wednesday, November 22, 1989 Martin Van Bommel, graduate student, Dept. of Computer Science, will speak on ``Functional Dependencies and Join Conditions in Object-Oriented Data Models'' TIME: 2:30 p.m. ROOM: DC 1331 ABSTRACT Several kinds of explicit constraints for the relational model have proven invaluable in appraising a choice of relation schemes, in designing the physical database, and in optimizing queries. Variations of these constraints for object-oriented data models will almost certainly have the same benefits. In this talk, I will discuss two possible forms of constraints for a simple choice of object-oriented data model. Some preliminary results on applications of an ability to reason about these constraints will be examined. Sound and complete axiomatizations will be presented, followed by an outline of decision procedures for several special cases in which constraints satisfy further syntactic restrictions. November 15, 1989
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (12/01/89)
DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Tuesday, December 5, 1989 Mr. Dexter Bradshaw, graduate student, Dept. of Computer Science, will speak on ``Retrieval Optimization in the Minos Distributed Testbed.'' TIME: 10:30 a.m. ROOM: DC 1331 ABSTRACT MINOS is a distributed data management system that supports the management of complex data objects. Particular emphasis is given to the management of complex multimedia data (text, voice, images, video etc.). This thesis describes the design, implementation and performance evaluation of algorithms for improving the retrieval performance of the system. Three types of performance optimizations are described. Query evaluation performance is improved by introducing buffering and scheduling algorithms that exploit the sequential characteristics of the access methods used by the system for queries involving text and attribute searches. Data retrieval from the database server is improved by reducing the disk exchanges in jukebox server architectures through appropriate long term scheduling algorithms. Finally, network traffic is reduced by using set processing, routing and flow control protocols between the data server and its clients. November 30, 1989
wlrush@water.waterloo.edu (Wenchantress Wench Wendall) (12/08/89)
DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF WATERLOO SEMINAR ACTIVITIES MASTER'S THESIS PRESENTATION -Thursday, December 14, 1989 Ms. Yvonne Dubreuil, graduate student, Dept. of Computer Science, will speak on ``The Integration of Buffer Management and Recovery Management.'' TIME: 2:30 p.m. ROOM: DC 1304 ABSTRACT The basics of IBM's ARIES Database Recovery System will be discussed. This system uses fuzzy checkpoints thus all the buffers containing dirty pages do not have to be written out during checkpointing. The cost of checkpointing is significantly reduced especially with the large buffer pools in use today. Buffer Managers and Recovery Managers tend to be at odds with each other. The buffer manager wants to keep pages it expects to be accessed in the near future in the buffer pool while the recovery manager wants to write out the pages that will poorly affect its recovery performance. I will discuss a buffer manager, ODPF (Oldest Dirty Page First), that bases its criteria for page replacement on data that is used by the recovery system thus having the effect of lowering the I/O cost of recovery even further. Performance results based on simulation will also be presented. December 7, 1989