Investigation of 'off-line‘ relaxation phenomena in oil filled transformers

Power transformers are one of the most important and costly equipment in power generation, transmission and distribution systems. Current average age of transformers in Australia is around 25 years and there is a strong economical tendency to use them up to 50 years or more. As the transformers operate, they get degraded due to different loading and environmental operating stressed conditions. In today‘s competitive energy market with the penetration of distributed energy sources, the transformers are stressed more with minimum required maintenance. The modern asset management program tries to increase the usage life time of power transformers with prognostic techniques using condition indicators. In the case of oil filled transformers, condition monitoring methods based on dissolved gas analysis, polarization studies, partial discharge studies, frequency response analysis studies to check the mechanical integrity, IR heat monitoring and other vibration monitoring techniques are in use. In the current research program, studies have been initiated to identify the degradation of insulating materials by the electrical relaxation technique known as dielectrometry. Aging leads to main degradation products like moisture and other oxidized products due to fluctuating thermal and electrical loading. By applying repetitive low frequency high voltage sine wave perturbations in the range of 100 to 200 V peak across available terminals of power transformer, the conductive and polarization parameters of insulation aging are identified. An in-house novel digital instrument is developed to record the low leakage response of repetitive polarization currents in three terminals configuration. The technique is tested with known three transformers of rating 5 kVA or more. The effects of stressing polarization voltage level, polarizing wave shapes and various terminal configurations provide characteristic aging relaxation information. By using different analyses, sensitive parameters of aging are identified and it is presented in this thesis.

Film, cinema, screen

Screen industries around the globe are evolving. While technological change has been slower to take effect upon the Australian film industry than other creative sectors such as music and publishing, all indications suggest that local screen practices are in a process of fundamental change. Fragmenting audiences, the growth of digital video, distribution and exhibition, the potential for entirely new forms of cultural expression, the proliferation of multi-platforms, and the importance of social networking and viral marketing in promoting products, are challenging traditional approaches to ‘film making’. Moreover, there has been a marked transition in government policy rationales and funding models in recent years, resulting in the most significant overhaul of public finance structures for the film industry in almost 20 years. Film, Cinema, Screen evaluates the Australian film industry’s recent development – particularly in terms of Australian feature film and television series production; it also advocates new approaches to Australian film, and address critical issues around how screen production globally is changing, with implications for local screen industries.

A prototype system for the digital lodgement of spatial data

This dissertation develops the model of a prototype system for the digital lodgement of spatial data sets with statutory bodies responsible for the registration and approval of land related actions under the Torrens Title system. Spatial data pertain to the location of geographical entities together with their spatial dimensions and are classified as point, line, area or surface. This dissertation deals with a sub-set of spatial data, land boundary data that result from the activities performed by surveying and mapping organisations for the development of land parcels. The prototype system has been developed, utilising an event-driven paradigm for the user-interface, to exploit the potential of digital spatial data being generated from the utilisation of electronic techniques. The system provides for the creation of a digital model of the cadastral network and dependent data sets for an area of interest from hard copy records. This initial model is calibrated on registered control and updated by field survey to produce an amended model. The field-calibrated model then is electronically validated to ensure it complies with standards of format and content. The prototype system was designed specifically to create a database of land boundary data for subsequent retrieval by land professionals for surveying, mapping and related activities. Data extracted from this database are utilised for subsequent field survey operations without the need to create an initial digital model of an area of interest. Statistical reporting of differences resulting when subsequent initial and calibrated models are compared, replaces the traditional checking operations of spatial data performed by a land registry office. Digital lodgement of survey data is fundamental to the creation of the database of accurate land boundary data. This creation of the database is fundamental also to the efficient integration of accurate spatial data about land being generated by modem technology such as global positioning systems, and remote sensing and imaging, with land boundary information and other information held in Government databases. The prototype system developed provides for the delivery of accurate, digital land boundary data for the land registration process to ensure the continued maintenance of the integrity of the cadastre. Such data should meet also the more general and encompassing requirements of, and prove to be of tangible, longer term benefit to the developing, electronic land information industry.

Legislative and security requirements of audit material for evidentiary purpose

This research used the Queensland Police Service, Australia, as a major case study. Information on principles, techniques and processes used, and the reason for the recording, storing and release of audit information for evidentiary purposes is reported. It is shown that Law Enforcement Agencies have a two-fold interest in, and legal obligation pertaining to, audit trails. The first interest relates to the situation where audit trails are actually used by criminals in the commission of crime and the second to where audit trails are generated by the information systems used by the police themselves in support of the recording and investigation of crime. Eleven court cases involving Queensland Police Service audit trails used in evidence in Queensland courts were selected for further analysis. It is shown that, of the cases studied, none of the evidence presented was rejected or seriously challenged from a technical perspective. These results were further analysed and related to normal requirements for trusted maintenance of audit trail information in sensitive environments with discussion on the ability and/or willingness of courts to fully challenge, assess or value audit evidence presented. Managerial and technical frameworks for firstly what is considered as an environment where a computer system may be considered to be operating “properly” and, secondly, what aspects of education, training, qualifications, expertise and the like may be considered as appropriate for persons responsible within that environment, are both proposed. Analysis was undertaken to determine if audit and control of information in a high security environment, such as law enforcement, could be judged as having improved, or not, in the transition from manual to electronic processes. Information collection, control of processing and audit in manual processes used by the Queensland Police Service, Australia, in the period 1940 to 1980 was assessed against current electronic systems essentially introduced to policing in the decades of the 1980s and 1990s. Results show that electronic systems do provide for faster communications with centrally controlled and updated information readily available for use by large numbers of users who are connected across significant geographical locations. However, it is clearly evident that the price paid for this is a lack of ability and/or reluctance to provide improved audit and control processes. To compare the information systems audit and control arrangements of the Queensland Police Service with other government departments or agencies, an Australia wide survey was conducted. Results of the survey were contrasted with the particular results of a survey, conducted by the Australian Commonwealth Privacy Commission four years previous, to this survey which showed that security in relation to the recording of activity against access to information held on Australian government computer systems has been poor and a cause for concern. However, within this four year period there is evidence to suggest that government organisations are increasingly more inclined to generate audit trails. An attack on the overall security of audit trails in computer operating systems was initiated to further investigate findings reported in relation to the government systems survey. The survey showed that information systems audit trails in Microsoft Corporation's “Windows” operating system environments are relied on quite heavily. An audit of the security for audit trails generated, stored and managed in the Microsoft “Windows 2000” operating system environment was undertaken and compared and contrasted with similar such audit trail schemes in the “UNIX” and “Linux” operating systems. Strength of passwords and exploitation of any security problems in access control were targeted using software tools that are freely available in the public domain. Results showed that such security for the “Windows 2000” system is seriously flawed and the integrity of audit trails stored within these environments cannot be relied upon. An attempt to produce a framework and set of guidelines for use by expert witnesses in the information technology (IT) profession is proposed. This is achieved by examining the current rules and guidelines related to the provision of expert evidence in a court environment, by analysing the rationale for the separation of distinct disciplines and corresponding bodies of knowledge used by the Medical Profession and Forensic Science and then by analysing the bodies of knowledge within the discipline of IT itself. It is demonstrated that the accepted processes and procedures relevant to expert witnessing in a court environment are transferable to the IT sector. However, unlike some discipline areas, this analysis has clearly identified two distinct aspects of the matter which appear particularly relevant to IT. These two areas are; expertise gained through the application of IT to information needs in a particular public or private enterprise; and expertise gained through accepted and verifiable education, training and experience in fundamental IT products and system.