Thesis (M.A.)--University of Hong Kong, 1991.

Thesis (M.A.)--University of Hong Kong, 1991. / Also available in print.

Thesis (M.A.)--University of Hong Kong, 2000. / Includes bibliographical references (p. i-xi).

Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2008.

Thesis (M.A.)--University of Hong Kong, 2000. / Includes bibliographical references (p. i-xi). Also available in print.

We present the design and implementation of a Certified Core Policy Language (ACCPL) that can be used to express access-control rules and policies. Although full-blown access-control policy languages such as eXtensible Access Control Markup Language (XACML) [OAS13] already exist, because access rules in such languages are often expressed in a declarative manner using fragments of a natural language like English, it isn’t alwaysclear what the intended behaviour of the system encoded in these access rules should be. To remedy this ambiguity, formal specification of how an access-control mechanism should behave, is typically given in some sort of logic, often a subset of first order logic. To show that an access-control system actually behaves correctly with respect to its specification, proofs are needed, however the proofs that are often presented in the literature are hard or impossible to formally verify. The verification difficulty is partly due to the fact that the language used to do the proofs while mathematical in nature, utilizes intuitive justifications to derive the proofs. Intuitive language in proofs means that the proofs could be incomplete and/or contain subtle errors. ACCPL is small by design. By small we refer to the size of the language; the syntax, auxiliary definitions and the semantics of ACCPL only take a few pages to describe. This compactness allows us to concentrate on the main goal of this thesis which is the ability to reason about the policies written in ACCPL with respect to specific questions. By making the language compact, we have stayed away from completeness and expressive power in several directions. For example, ACCPL uses only a single policy combinator, the conjunction policy combinator. The design of ACCPL is therefore a trade-off between ease of formal proof of correctness and expressive power. We also consider ACCPL a core policy access-control language since we have retained the core features of many access-control policy languages. For instance ACCPL employs a single condition type called a “prerequisite” where other languages may have very expressive and rich sets of conditions.

Thesis (M.A.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 38-43).

Thesis (M.A.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 38-43). Also available in print.

Gaelic in Scotland has been undergoing language shift, with both a decline in the number of speakers and domains in which the language is routinely used. The Gaelic Language (Scotland) Act of 2005 aimed to secure the status of the language and under its provision required public authorities based in Scotland to prepare Gaelic language plans. This thesis explored the interplay of these formal language management initiatives and linguistic practices in Stornoway, the largest settlement in the Western Isles, the last remaining heartland of the language in Scotland. Linguistic soundscape surveys collected data in real time and in situ in ten different public spaces, both with and without statutory Gaelic language plans, to assess how, when, and by whom, and for what purpose Gaelic was used. This data was supplemented by eleven language use diaries of bilingual Gaelic/English speakers residing in Stornoway. This quantitative data was used to evaluate individual linguistic practices and how these varied across the different domains of communication, including closed domains not covered by the linguistic soundscape surveys. The findings of this study indicate that Gaelic was not used as extensively as might statistically be expected, but that the language makes a significant contribution to the linguistic soundscape of the community, especially in interactions involving participants over the age of 60 and in private domain interactions. Bilingual Gaelic / English speakers use Gaelic in circumstances where they do not have to (re-)negotiate Gaelic as an accepted linguistic norm. This was especially the case in social networks and closed domains such as places of work or education. Gaelic was used to a lesser extent in public domain interactions, and only where members of staff used Gaelic in the linguistic soundscape of that particular space.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 256-262).