No description available.

Anonymizers based on an intermediate computer (a set of them) located between the sender and the receiver of an e-mail message have been used for several years by senders of e-mail messages who do not wish to disclose their identity to the receivers. The job of the computer in the middle (the mediator) is to receive the message from the sender, delete the sender's address and other personal data from the header of the message, and forward the message to its final destination. In this paradigm, there are no means to hide the identity of the user from the mediator simple because the message sent arrives in the middle computer, with information that easily leads to the identity of the sender. The origin of this problem is that the sender uses a computer identified by an IP-address that unambiguously leads to the identity of its user. In fact, the sender discloses his identity to the mediator computer from the very moment lie sends his message in the hope that the mediator will protect it. Because of this, in this paradigm the strength of the system for protecting the identity of the sender depends on the ability and willingness of the mediator to keep the secret. In this dissertation we propose a novel approach to sending truly anonymous and confidential messages over the Internet which does not depend on a third party. Our idea departs from the mediator approach in that we do not use an IP-addressed computer to send anonymous messages, we use an IP-addressless computer instead, to be specific, we use a Personal Digital Assistant (PDA) which is IP-addresslessly connected to the Internet with the support of a Mobile Support Station (MSS). The PDA is identified by the MSS by a temporary, non-personal, random identifier (TmpId) which is assigned by the MSS and is valid only for one communication session. Thanks to the use of the TmpId, the sender of the anonymous messages does not need to disclose his identity to the MSS or to anybody else; thus, the strength of the system does not depend on any mediator. Having observed that a public telephone box provides complete anonymity when operated by coins, we took its functionality as a paradigm for our system. Thus, the main idea of our approach is to make the PDA, the MSS, and the Internet communication infrastructure imitate the work of a public telephone box connected to the telephone network. For this to be possible the PDA user uses anonymous electronic cash to pay for his anonymous message. To prove the feasibility of our approach and its correctness, the protocol of the proposed system was designed, specified in Promela specification language, and its basic safety properties and proper end-states were validated using the Spin validator.

This thesis examines the roles of governors within the contexts of the national framework for governance and the effect they have on schools. The field of research into the effects of school governors is an infant one. Little direct observation of governance has taken place and there is no true experimental research. In the absence of such work, the project developed a definition of effective governance through consideration of the descriptions of and prescriptions for governor activity. It used the definition to develop two research instruments. The first of these, a national questionnaire, produced some specific examples of a range of activities for governors and lead to the development of a second instrument. This, a schedule for semi- structured interviews, was applied to six case study schools. In these studies, governors and headteachers were interviewed conceming the characteristics of their goveming bodies and the outcomes for the schools were set against these characteristics. What emerges from these comparisons are some clear associations between effective outcomes and certain governor activities. These include training, monitoring, clear support for the school, the degree of trust gained with the staff, detailed knowledge of the school, and participation in school development planning. Overall, the conclusions point to connections between the manner in which governors conduct themselves and their business and the successes of the school that they govern.

Classifying pipe cracks by size from their pulse-echo ultrasonic signal is difficult but highly significant for the defect evaluation required in pipe testing and maintenance decision making. For this thesis, a binary Support Vector Machine (SVM) classifier, which divides pipe cracks into two categories: large and small, was developed using collected ultrasonic signals. To improve the performance of this SVM classifier in terms of reducing test errors, we first combined the Sequential Backward Selection and Sequential Forward Selection schemes for input feature reduction. Secondly, we used the data dependent kernel instead of the Gaussian kernel as the kernel function in the SVM classifier. Thirdly, as it is time-consuming to use the classic grid-search method for parameter selection of SVM, this work proposes a Kernel Fisher Discriminant Ratio (KFD Ratio) which makes it possible to more quickly select parameters for the SVM classifier.

Thesis (MBus)--University of South Australia, 1998

Thesis (PhD) -- University of South Australia, 1998

No description available.

No description available.

No description available.

Thesis (MBus)--University of South Australia, 1998