50,922 Works

A semi-automatic approach to protocol implementation : the ISO class 2 Transport protocol as an example

Allen Chakming Lau
Formal Description Techniques (FDTs) for specifying communication protocols, and the adopted FDT standards such as Estelle have opened a new door for the possibility of automating the implementation of a complex communication protocol directly from its specification. After a brief overview of Estelle FDT, we present the basic ideas and the encountered problems in developing a C-written Estelle compiler, which accepts an Estelle specification of protocols and produces a protocol implementation in C. The practicality...

A model of grammar based on principles of government and binding

Randall Martin Sharp
This thesis describes an implementation of a model of natural language grammar based on current theories of transformational grammar, collectively referred to as Government and Binding (GB) theory. A description is presented of the principles of GB, including X-bar syntax and the theories of Case, Theta, Binding, Bounding, and Government The principles, in effect, constitute an embodiment of "universal grammar" (UG), i.e. the abstract characterization of the innately endowed human language faculty. Associated with the...

Characterizing user workload for capacity planning

Jee Fung Pang
With the widespread use of computers in today's industry, planning system configurations in computer sites plays an increasingly important role. The process of planning system configurations or determining hardware requirements for new or existing systems is commonly known as capacity planning among performance researchers and analysts. This thesis presents a refined capacity planning process for centralized computing system, with special attention to characterizing user workload for capacity planning. The objective is to make the entire...

An algorithm for polyhedron modelling and its implementation

Kwai-Biu Ricky Yeung
This thesis describes an algorithm for calculating the theoretic set operations union, intersection, and difference of two polyhedra. The polyhedra are in the Eulerian surface description format, specified by their vertices, edges, and faces. The representation of polyhedra is based on the unambiguous Boundary Representation scheme. The domain of this algorithm includes all flat-surfaced polyhedra; however, nested holes and curved surfaces are not permitted. The thesis is divided into three parts. The first part presents...

A state-dependent policy for computer system load regulation

William Chun Mun Wong
One of the principal ideas behind multiprogramming is to make more effective use of the system resources. However, in order to avoid excessive interactions among the competing jobs, which will result in general degradation of system performance, the number and composition of jobs in the multiprogramming set should be carefully controlled. This is the function of the load-control policy. A good load-control policy should be adaptive to work load variation. A load-control policy based on...

An Estelle-C compiler for automatic protocol implementation

Robin Isaac Man-Hang Chan
Over the past few years, much experience has been gained in semi-automatic protocol implementation using an existing Estelle-C compiler developed at the University of British Columbia. However, with the continual evolution of the Estelle language, that compiler is now obsolete. The present study found substantial syntactic and semantic differences between the Estelle language as implemented by the existing compiler and that specified in the latest ISO document to warrant the construction of a new Estelle-C...

Integrating local area networks to improve reliability and performance

Kenneth Chi-Kin Chan
A hybrid network comprising an Ethernet and a Cambridge Ring has been proposed by researchers in the Department of Computer Science at the University of British Columbia as a means for improving reliablility and performance of computer communication in a local area network environment. This thesis explores the practicability of this concept and constructs a generalization of this model, where an arbitrary number of LANs, of arbitrary technologies, may be used together in an integrated...

A message-based remote database access facility

Neil Karl Koorland
We present a design for a remote database access facility, which uses a message system as its communication medium. Adopting a message-based design offers a number of advantages over more conventional connection-oriented architectures for those remote database applications where the interaction between user and DBMS involves a single query followed by a single result. By complying with the CCITT X.400 Recommendations on Message Handling Systems, the design allows for networkwide access to remote DBMSs that...

Modelling and animating three-dimensional articulate figures

Danny G. Cachola
This thesis describes an animation extension to a high-level graphical programming language which provides constructs for the definition, manipulation, and external representation of three-dimensional articulate figures and and their associated movements. The extension permits the definition of models consisting of segments and joints and the specification of each model's motion at a high level of abstraction. The relationship of the extension with respect to the host language is discussed and a general description of the...

On implementing the ISO File Transfer, Access and Management protocol for a UNIX 4.2 BSD environment

Mei Jean Goh
Different computer systems have their own ways of representing, storing and managing files. One approach to facilitate file transfers among systems in a heterogeneous networked environment is for each system to locally map files for transfer onto a virtual filestore (VFS). Conceptually, a virtual filestore provides a universal model for describing files and how they can be manipulated. The ISO File Transfer, Access and Management (FTAM) protocol offers one such virtual filestore model. This thesis...

Implementation of Team Shoshin : an exercise in porting and multiprocess structuring of the kernel

Huay-Yong Wang
Team Shoshin is an extension of Shoshin, a testbed for distributed software originally developed on the LSI ll/23s at the University of Waterloo. This thesis presents a description of the implementation of Team Shoshin on the Sun Workstation. With wide disparity in the underlying hardware, a major part of our initial development effort was to port Shoshin to its new hardware. The problems and design decisions faced by the porting effort and how they were...

Implementation methods for singularly perturbed two-point boundary value problems

Simon Jacobs
In this thesis we consider the numerical solution of singularly perturbed two-point boundary value problems in ordinary differential equations. We examine implementation methods for general purpose solvers of first order linear systems. The basic difference scheme is collocation at Gauss points, with a new symmetric Runge-Kutta implementation. Adaptive mesh selection is based on localized error estimates at the collocation points. These methods are implemented as modifications to the successful collocation code, COLSYS (Ascher, Christiansen &...

Conformance testing of OSI protocols : the class O transport protocol as an example

Tian Kou
This thesis addresses the problem of conformance testing of communication protocol implementations. Test sequence generation techniques for finite state machines (FSM) have been developed to solve the problem of high costs of an exhaustive test. These techniques also guarantee a complete coverage of an implementation in terms of state transitions and output functions, and therefore provide a sound test of the implementation under test. In this thesis, we have modified and applied three test sequence...

Specification-verification of protocols : the significant event temporal logic technique

George Tsiknis
This thesis addresses the problem of protocol verification. We first present a brief review of the existing specification methods for communication protocols, with emphasis on the hybrid techniques. The alternating bit protocol is specified in ISO/FDT, BBN/FST and UNISPEX to provide a comparison between three interesting hybrid models of protocol specification. A method for applying the unbounded state Temporal Logic to verify a protocol specified in a hybrid technique (in particular FDT) is outlined. Finally,...

A numerical investigation of two boundary element methods

Mui Hoon Quek
This thesis investigates the viability of two boundary element methods for solving steady state problems, the continuous least squares method and the Galerkin minimization technique. In conventional boundary element methods, the singularities of the fundamental solution involved are usually located at fixed points on the boundary of the problem's domain or on an auxiliary boundary. This leads to some difficulties: when the singularities are located on the problem domain's boundary, it is not easy to...

A high-order accurate particle-in-cell method

Essex Edwards
We propose the use of high-order accurate interpolation and approximation schemes alongside high-order accurate time integration methods to enable high-order accurate Particle-in-Cell methods. The key insight is to view the unstructured set of particles as the underlying representation of the continuous fields; the grid used to evaluate integro-differential coupling terms is purely auxiliary. We also include a novel regularization term to avoid the accumulation of noise in the particle samples without harming the convergence rate....

A prolog implementation of a subset of Marcus’ parser and its relation to the handling of extragrammatical input

Michael Scarlett Dorotich
In any system employing a natural language interface, there is the problem that, by means of a formal grammar, the system itself defines the language it will accept. But, when using language, people will not always adhere to the rules of this grammar; therefore, a natural language computer system should not simply treat as incomprehensible any input not conforming to its internal grammar, input we may call extragrammatical. The term extragrammatical refers to input that...

Implementation of a logic programming language : R-Maple and its extension to include functions

Benjamin Yu
The use of logic as a language for communication with computers has been exploited in various research areas. R-Maple is a logic programming language, designed by Paul Voda, which improves on some of the short-comings of Prolog. The implementation details of R-Maple will be discussed. R-Maple is a relational programming language which has relations as its basic objects. It can be extended to include functions to form a functional and relational programming language. The advantage...

Schema labelling applied to hand-printed Chinese character recognition

Timothy Paul Bult
Hand-printed Chinese character recognition presents an interesting problem for Artificial Intelligence research. Input data in the form of arrays of pixel values cannot be directly mapped to unique character identifications because of the complexity of the characters. Thus, intermediate data structures are necessary, which in turn lead to a need to represent knowledge of the characters' composition. Building the intermediate constructs for these hand-printed characters necessarily involves choices among ambiguities, the set of which is...

The design and implementation of the Cambridge ring protocols

Julian Hong Pak Wong
Protocol implementation is characterized by various issues such as concurrency, time-critical responses, and asynchronous events. Such issues would be easier to resolve if the underlying operating system provides a hospitable environment that include an efficient interprocess communication facility. Most operating systems, however, do not provide such an environment. This thesis presents an implementation and discusses what has been learned -in implementing the Byte Stream and the Basic Block protocols of the Cambridge Ring on a...

Implementation of microcomputers in elementary schools : a survey and evaluation

Christine Wai-Chi Chan
The objective of this thesis is to investigate the uses of computer aided learning (CAL) at the elementary level. Some recent publications on CAL are summarized and discussed. A questionnaire was used and interviews were conducted with elementary teachers in four chosen school districts in Vancouver and Toronto. From this field research, information was collected on teachers' perceptions on the use of CAL in the elementary classroom. This data is compared with observations presented in...

An environment theory with precomplete negation over pairs

James H. Andrews
A formal semantics of Voda's Theory of Pairs is given which takes the natural-deduction form of Gilmore's first-order set theory. The complete proof theory corresponding to this semantics is given. Then, a logic programming system is described in the form of a computational proof theory for the Gilmore semantics. This system uses parallel disjunction and the technique of precomplete negation; these features are shown to make it more complete than conventional logic programming languages. Finally,...

The intermediate machine approach to distributed computing system design

Gordon Peter Simon
This thesis proposes that an intermediate machine be viewed as the software base of a distributed operating system. In this role the services provided to the operating system by the intermediate machine are similar to those provided by a security kernel. Such an intermediate machine software base differs from the traditional security kernel in that it additionally provides an interpreted instruction set. The advantage of this approach is that software extension of a machine architecture...

A schema & constraint-based representation to understanding natural language

Eliza Wing-Mun Kuttner
This thesis attempts to represent the syntax and semantics of English sentences using a schema and constraint-based approach. In this approach, syntactic and semantic knowledge that are represented by schemata are processed in parallel with the utilization of network consistency techniques and an augmented version of Earley's context-free parsing algorithm. A sentence's syntax and semantics are disambiguated incrementally as the interpretation proceeds left to right, word by word. Each word and recognized grammatical constituent provide...

Design and implementation of an event monitor for the unix operating system

Susan Chui-Sheung Chan
Tuning a computer system effectively requires prior studies on the performance of the system. There are different types of tools available to measure a system: hardware, firmware and software. This thesis presents the design and implementation of an event monitor, which is one type of software tools. The event monitor was developed on a SUN1 workstation running UNIX 4.2bsd version 1.4. Six types of events were selected to be measured, namely transactions, logins/logouts, pageins, pageouts,...

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