In this study, we consider the disassembly problem of end-of-life (EOL) products for recovering valuable parts or assemblies. All parts obtained by disassembly processes of an EOL product may not be profitable due to their high recovery costs. Our problem is to select the parts to be released and determine the associated disassembly tasks so as to maximize the total profit. We first tackle the simple part selection problem, and then introduce a time constraint for the tasks to be performed for selected parts and search for incomplete time constrained sequences. We formulate our first problem as a Mixed Integer Problem and show that the constraint set of this formulation is totally unimodular. We also provide the dual formulation of our problem and its interpretation. For time-constrained part selection problem we propose a branch-and-bound algorithm. We first develop some reduction mechanism to reduce the size of the problem. Our solution procedure is capable of solving problems with up to 94 parts and tasks.

The purpose of this thesis was to research the systems issues surrounding identity fraud in New Zealand. There is only limited published research on the topic, either at an academic or industry level. The New Zealand Government has been conducting work in identity fraud in recent times but New Zealand appears to be lagging behind other similar westernised countries in terms of developing specific identity fraud policy or legislative provisions. The research showed that New Zealand does have serious problems in its systems, which in some cases facilitate identity fraud. There is a lack of synchronicity between New Zealand Government systems which undermines a whole of government approach to minimising the risk of identity fraud. Issues in the private sector with identity fraud are just as serious, with financial advantage being one of the main reasons that identity fraud is committed. However, the lack of information sharing between the public and private sectors does not help stem the flow of identity fraud that is currently occurring. Finding policy solutions to combat identity fraud is far from being simplistic. Public policy in this area is fraught with social, political and financial implications. Identity fraud is committed with speed while public policy faces a slow battle with red tape. Nonetheless, the New Zealand Government does not even appear to categorically know what is happening on its own door step with respect to identity fraud. There are no statistics on identity fraud and no concrete figures as to the cost of identity fraud to New Zealand. To compound problems, identity fraud is not even an official offence classification so even when it is occurring, it is not always being recorded. The damage resulting from identity fraud can be catastrophic. Identity fraud is a breeder crime for other offences. It can enable an act of terrorism to occur, women and children to be trafficked, and organisations and individuals to suffer serious financial loss. In New Zealand however, the benefits of identity fraud can be great while the deterrents are weak. New Zealand faces potential harm to its international reputation if its systems are not strengthened to fight identity fraud. In order for this to occur, New Zealand needs to develop a specific identity fraud policy so that it has the basic knowledge in place to allocate the necessary resources to this problem.

Effective antenna selection and deployment strategies are important for reducing co-channel interference in indoor wireless systems. Low-cost solutions are essential, and strategies that utilise simple antennas (such as directional patches) are advantageous from this perspective. However, performance is always an issue and the improvements achievable through clever antenna deployment need to be quantified. In this thesis, an experimental investigation of indoor propagation comparing the performance of directional antennas and multiple-element arrays (MEAs) with omni-directional antennas is reported. Estimation of the performance of a direct sequence code division multiple access (DS-CDMA) system operating in a variety of deployment scenarios allows the identification of a range of performance-limiting factors and the optimal deployment strategies. It is shown that the orientation of single-element directional antennas can significantly impact on system performance compared to omni-directional antennas in traditional systems. The deployment of MEAs with an active diversity combining scheme can further improve system performance by more than one order of magnitude. From the perspective of system planning, the choice of antenna selection and deployment options depends on the current and future demand for system performance and the financial resources available. An evolutionary path has been proposed to provide a smooth transition from conventional (low-cost) to high-performance (high-cost) antenna systems as demand dictates. Other performance-limiting factors in indoor wireless systems include the physical environment and external interference. It is also shown that electromagnetically-opaque obstacles in the environment can amplify the effectiveness of the antenna deployment by acting as physical zone boundaries that restrict interference. External interference has been shown to cause a significant degradation to the performance of an indoor system when the carrier-to-external-interference ratio (CEIR) is below 30 dB. This performance degradation can be minimised by appropriate antenna deployment, although the optimum antenna orientations depends on the strength of the external interference.

Effective antenna selection and deployment strategies are important for reducing co-channel interference in indoor wireless systems. Low-cost solutions are essential, and strategies that utilise simple antennas (such as directional patches) are advantageous from this perspective. However, performance is always an issue and the improvements achievable through clever antenna deployment need to be quantified. In this thesis, an experimental investigation of indoor propagation comparing the performance of directional antennas and multiple-element arrays (MEAs) with omni-directional antennas is reported. Estimation of the performance of a direct sequence code division multiple access (DS-CDMA) system operating in a variety of deployment scenarios allows the identification of a range of performance-limiting factors and the optimal deployment strategies. It is shown that the orientation of single-element directional antennas can significantly impact on system performance compared to omni-directional antennas in traditional systems. The deployment of MEAs with an active diversity combining scheme can further improve system performance by more than one order of magnitude. From the perspective of system planning, the choice of antenna selection and deployment options depends on the current and future demand for system performance and the financial resources available. An evolutionary path has been proposed to provide a smooth transition from conventional (low-cost) to high-performance (high-cost) antenna systems as demand dictates. Other performance-limiting factors in indoor wireless systems include the physical environment and external interference. It is also shown that electromagnetically-opaque obstacles in the environment can amplify the effectiveness of the antenna deployment by acting as physical zone boundaries that restrict interference. External interference has been shown to cause a significant degradation to the performance of an indoor system when the carrier-to-external-interference ratio (CEIR) is below 30 dB. This performance degradation can be minimised by appropriate antenna deployment, although the optimum antenna orientations depends on the strength of the external interference.

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Effective antenna selection and deployment strategies are important for reducing co-channel interference in indoor wireless systems. Low-cost solutions are essential, and strategies that utilise simple antennas (such as directional patches) are advantageous from this perspective. However, performance is always an issue and the improvements achievable through clever antenna deployment need to be quantified. In this thesis, an experimental investigation of indoor propagation comparing the performance of directional antennas and multiple-element arrays (MEAs) with omni-directional antennas is reported. Estimation of the performance of a direct sequence code division multiple access (DS-CDMA) system operating in a variety of deployment scenarios allows the identification of a range of performance-limiting factors and the optimal deployment strategies. It is shown that the orientation of single-element directional antennas can significantly impact on system performance compared to omni-directional antennas in traditional systems. The deployment of MEAs with an active diversity combining scheme can further improve system performance by more than one order of magnitude. From the perspective of system planning, the choice of antenna selection and deployment options depends on the current and future demand for system performance and the financial resources available. An evolutionary path has been proposed to provide a smooth transition from conventional (low-cost) to high-performance (high-cost) antenna systems as demand dictates. Other performance-limiting factors in indoor wireless systems include the physical environment and external interference. It is also shown that electromagnetically-opaque obstacles in the environment can amplify the effectiveness of the antenna deployment by acting as physical zone boundaries that restrict interference. External interference has been shown to cause a significant degradation to the performance of an indoor system when the carrier-to-external-interference ratio (CEIR) is below 30 dB. This performance degradation can be minimised by appropriate antenna deployment, although the optimum antenna orientations depends on the strength of the external interference.

The purpose of this thesis was to research the systems issues surrounding identity fraud in New Zealand. There is only limited published research on the topic, either at an academic or industry level. The New Zealand Government has been conducting work in identity fraud in recent times but New Zealand appears to be lagging behind other similar westernised countries in terms of developing specific identity fraud policy or legislative provisions. The research showed that New Zealand does have serious problems in its systems, which in some cases facilitate identity fraud. There is a lack of synchronicity between New Zealand Government systems which undermines a whole of government approach to minimising the risk of identity fraud. Issues in the private sector with identity fraud are just as serious, with financial advantage being one of the main reasons that identity fraud is committed. However, the lack of information sharing between the public and private sectors does not help stem the flow of identity fraud that is currently occurring. Finding policy solutions to combat identity fraud is far from being simplistic. Public policy in this area is fraught with social, political and financial implications. Identity fraud is committed with speed while public policy faces a slow battle with red tape. Nonetheless, the New Zealand Government does not even appear to categorically know what is happening on its own door step with respect to identity fraud. There are no statistics on identity fraud and no concrete figures as to the cost of identity fraud to New Zealand. To compound problems, identity fraud is not even an official offence classification so even when it is occurring, it is not always being recorded. The damage resulting from identity fraud can be catastrophic. Identity fraud is a breeder crime for other offences. It can enable an act of terrorism to occur, women and children to be trafficked, and organisations and individuals to suffer serious financial loss. In New Zealand however, the benefits of identity fraud can be great while the deterrents are weak. New Zealand faces potential harm to its international reputation if its systems are not strengthened to fight identity fraud. In order for this to occur, New Zealand needs to develop a specific identity fraud policy so that it has the basic knowledge in place to allocate the necessary resources to this problem.

Effective antenna selection and deployment strategies are important for reducing co-channel interference in indoor wireless systems. Low-cost solutions are essential, and strategies that utilise simple antennas (such as directional patches) are advantageous from this perspective. However, performance is always an issue and the improvements achievable through clever antenna deployment need to be quantified. In this thesis, an experimental investigation of indoor propagation comparing the performance of directional antennas and multiple-element arrays (MEAs) with omni-directional antennas is reported. Estimation of the performance of a direct sequence code division multiple access (DS-CDMA) system operating in a variety of deployment scenarios allows the identification of a range of performance-limiting factors and the optimal deployment strategies. It is shown that the orientation of single-element directional antennas can significantly impact on system performance compared to omni-directional antennas in traditional systems. The deployment of MEAs with an active diversity combining scheme can further improve system performance by more than one order of magnitude. From the perspective of system planning, the choice of antenna selection and deployment options depends on the current and future demand for system performance and the financial resources available. An evolutionary path has been proposed to provide a smooth transition from conventional (low-cost) to high-performance (high-cost) antenna systems as demand dictates. Other performance-limiting factors in indoor wireless systems include the physical environment and external interference. It is also shown that electromagnetically-opaque obstacles in the environment can amplify the effectiveness of the antenna deployment by acting as physical zone boundaries that restrict interference. External interference has been shown to cause a significant degradation to the performance of an indoor system when the carrier-to-external-interference ratio (CEIR) is below 30 dB. This performance degradation can be minimised by appropriate antenna deployment, although the optimum antenna orientations depends on the strength of the external interference.

Thesis (Ph. D.)--University of Virginia, 2008. / Includes bibliographical references. Also available online through Digital Dissertations.