253 resultados para Averaging operators


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An increased interest in utilising groups of Unmanned Aerial Vehicles (UAVs) with heterogeneous capabilities and autonomy is presenting the challenge to effectively manage such during missions and operations. This has been the focus of research in recent years, moving from a traditional UAV management paradigm of n-to-1 (n operators for one UAV, with n being at least two operators) toward 1-to-n (one operator, multiple UAVs). This paper has expanded on the authors’ previous work on UAV functional capability framework, by incorporating the concept of Functional Level of Autonomy (F-LOA) with two configurations: The lower F-LOA configuration contains sufficient information for the operator to generate solutions and make decisions to address perturbation events. Alternatively, the higher F-LOA configuration presents information reflecting on the F-LOA of the UAV, allowing the operator to interpret solutions and decisions generated autonomously, and decide whether to veto from this decision.

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Bus travel time estimation and prediction are two important modelling approaches which could facilitate transit users in using and transit providers in managing the public transport network. Bus travel time estimation could assist transit operators in understanding and improving the reliability of their systems and attracting more public transport users. On the other hand, bus travel time prediction is an important component of a traveller information system which could reduce the anxiety and stress for the travellers. This paper provides an insight into the characteristic of bus in traffic and the factors that influence bus travel time. A critical overview of the state-of-the-art in bus travel time estimation and prediction is provided and the needs for research in this important area are highlighted. The possibility of using Vehicle Identification Data (VID) for studying the relationship between bus and cars travel time is also explored.

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Traffic congestion has a significant impact on the economy and environment. Encouraging the use of multimodal transport (public transport, bicycle, park’n’ride, etc.) has been identified by traffic operators as a good strategy to tackle congestion issues and its detrimental environmental impacts. A multi-modal and multi-objective trip planner provides users with various multi-modal options optimised on objectives that they prefer (cheapest, fastest, safest, etc) and has a potential to reduce congestion on both a temporal and spatial scale. The computation of multi-modal and multi-objective trips is a complicated mathematical problem, as it must integrate and utilize a diverse range of large data sets, including both road network information and public transport schedules, as well as optimising for a number of competing objectives, where fully optimising for one objective, such as travel time, can adversely affect other objectives, such as cost. The relationship between these objectives can also be quite subjective, as their priorities will vary from user to user. This paper will first outline the various data requirements and formats that are needed for the multi-modal multi-objective trip planner to operate, including static information about the physical infrastructure within Brisbane as well as real-time and historical data to predict traffic flow on the road network and the status of public transport. It will then present information on the graph data structures representing the road and public transport networks within Brisbane that are used in the trip planner to calculate optimal routes. This will allow for an investigation into the various shortest path algorithms that have been researched over the last few decades, and provide a foundation for the construction of the Multi-modal Multi-objective Trip Planner by the development of innovative new algorithms that can operate the large diverse data sets and competing objectives.

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For the timber industry, the ability to simulate the drying of wood is invaluable for manufacturing high quality wood products. Mathematically, however, modelling the drying of a wet porous material, such as wood, is a diffcult task due to its heterogeneous and anisotropic nature, and the complex geometry of the underlying pore structure. The well{ developed macroscopic modelling approach involves writing down classical conservation equations at a length scale where physical quantities (e.g., porosity) can be interpreted as averaged values over a small volume (typically containing hundreds or thousands of pores). This averaging procedure produces balance equations that resemble those of a continuum with the exception that effective coeffcients appear in their deffnitions. Exponential integrators are numerical schemes for initial value problems involving a system of ordinary differential equations. These methods differ from popular Newton{Krylov implicit methods (i.e., those based on the backward differentiation formulae (BDF)) in that they do not require the solution of a system of nonlinear equations at each time step but rather they require computation of matrix{vector products involving the exponential of the Jacobian matrix. Although originally appearing in the 1960s, exponential integrators have recently experienced a resurgence in interest due to a greater undertaking of research in Krylov subspace methods for matrix function approximation. One of the simplest examples of an exponential integrator is the exponential Euler method (EEM), which requires, at each time step, approximation of φ(A)b, where φ(z) = (ez - 1)/z, A E Rnxn and b E Rn. For drying in porous media, the most comprehensive macroscopic formulation is TransPore [Perre and Turner, Chem. Eng. J., 86: 117-131, 2002], which features three coupled, nonlinear partial differential equations. The focus of the first part of this thesis is the use of the exponential Euler method (EEM) for performing the time integration of the macroscopic set of equations featured in TransPore. In particular, a new variable{ stepsize algorithm for EEM is presented within a Krylov subspace framework, which allows control of the error during the integration process. The performance of the new algorithm highlights the great potential of exponential integrators not only for drying applications but across all disciplines of transport phenomena. For example, when applied to well{ known benchmark problems involving single{phase liquid ow in heterogeneous soils, the proposed algorithm requires half the number of function evaluations than that required for an equivalent (sophisticated) Newton{Krylov BDF implementation. Furthermore for all drying configurations tested, the new algorithm always produces, in less computational time, a solution of higher accuracy than the existing backward Euler module featured in TransPore. Some new results relating to Krylov subspace approximation of '(A)b are also developed in this thesis. Most notably, an alternative derivation of the approximation error estimate of Hochbruck, Lubich and Selhofer [SIAM J. Sci. Comput., 19(5): 1552{1574, 1998] is provided, which reveals why it performs well in the error control procedure. Two of the main drawbacks of the macroscopic approach outlined above include the effective coefficients must be supplied to the model, and it fails for some drying configurations, where typical dual{scale mechanisms occur. In the second part of this thesis, a new dual{scale approach for simulating wood drying is proposed that couples the porous medium (macroscale) with the underlying pore structure (microscale). The proposed model is applied to the convective drying of softwood at low temperatures and is valid in the so{called hygroscopic range, where hygroscopically held liquid water is present in the solid phase and water exits only as vapour in the pores. Coupling between scales is achieved by imposing the macroscopic gradient on the microscopic field using suitably defined periodic boundary conditions, which allows the macroscopic ux to be defined as an average of the microscopic ux over the unit cell. This formulation provides a first step for moving from the macroscopic formulation featured in TransPore to a comprehensive dual{scale formulation capable of addressing any drying configuration. Simulation results reported for a sample of spruce highlight the potential and flexibility of the new dual{scale approach. In particular, for a given unit cell configuration it is not necessary to supply the effective coefficients prior to each simulation.

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The assembly of retroviruses is driven by oligomerization of the Gag polyprotein. We have used cryo-electron tomography together with subtomogram averaging to describe the three-dimensional structure of in vitro-assembled Gag particles from human immunodeficiency virus, Mason-Pfizer monkey virus, and Rous sarcoma virus. These represent three different retroviral genera: the lentiviruses, betaretroviruses and alpharetroviruses. Comparison of the three structures reveals the features of the supramolecular organization of Gag that are conserved between genera and therefore reflect general principles of Gag-Gag interactions and the features that are specific to certain genera. All three Gag proteins assemble to form approximately spherical hexameric lattices with irregular defects. In all three genera, the N-terminal domain of CA is arranged in hexameric rings around large holes. Where the rings meet, 2-fold densities, assigned to the C-terminal domain of CA, extend between adjacent rings, and link together at the 6-fold symmetry axis with a density, which extends toward the center of the particle into the nucleic acid layer. Although this general arrangement is conserved, differences can be seen throughout the CA and spacer peptide regions. These differences can be related to sequence differences among the genera. We conclude that the arrangement of the structural domains of CA is well conserved across genera, whereas the relationship between CA, the spacer peptide region, and the nucleic acid is more specific to each genus.

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Restoring a large-scale power system has always been a complicated and important issue. A lot of research work has been done on different aspects of the whole power system restoration procedure. However, more time will be required to complete the power system restoration process in an actual situation if accurate and real-time system data cannot be obtained. With the development of the wide area monitoring system (WAMS), power system operators are capable of accessing to more accurate data in the restoration stage after a major outage. The ultimate goal of the system restoration is to restore as much load as possible while in the shortest period of time after a blackout, and the restorable load can be estimated by employing WAMS. Moreover, discrete restorable loads are employed considering the limited number of circuit-breaker operations and the practical topology of distribution systems. In this work, a restorable load estimation method is proposed employing WAMS data after the network frame has been reenergized, and WAMS is also employed to monitor the system parameters in case the newly recovered system becomes unstable again. The proposed method has been validated with the New England 39-Bus system and an actual power system in Guangzhou, China.

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The aim of this study is to investigate the compliance impact of price queries issued by a securities market operator to its participating firms. Market operators in Australia and New Zealand, such as the Australian Securities Exchange and the New Zealand Securities Exchange, have the regulatory power in their rules to issue queries to its market participants to explain unusual fluctuations in trading price or volume in the market. The operator will issue a price query where it believes that the market has not been fully informed as to price relevant information. Responsive regulation has informed much of the regulatory debate in securities laws in our region. We posit that price queries are one strategy that a market operator can use in communicating its enforcement expectations to its stakeholder. However, whilst responsive regulation informs regulatory choices, an alternate view seeks to explain why participants respond to these regulatory strategies, and we use disclosure behaviour after price queries to test compliance behaviour

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The Australian Federal Government has recently passed reforms to the shipping industry. These reforms are aimed at removing barriers to investment in Australian shipping, fostering global competitiveness and securing a stable maritime skills base. The shipping reform package adopts a two pronged approach designed to achieve its stated goals by providing both a ‘stick’ and ‘carrot’ to industry participants. First, the ‘stick’ is delivered via the provision of tighter regulation of coastal trading operations through a new licencing system, along with the introduction of a civil penalty regime and an increase in existing penalties. Second, the ‘carrot’ is delivered via taxation incentives available to vessels registered in Australia where the registrant meets certain specified criteria. These incentives, introduced through amendments to the Income Tax Assessment Act 1997 and the Income Tax Assessment Act 1936 and contained in the Tax Laws Amendment (Shipping Reform) Act 2012, provide five key tax incentives to the shipping industry. From 1 July 2012, amendments give effect to an income tax exemption for qualifying ship operators, accelerated depreciation of vessels, roll-over relief from income tax on the sale of a vessel, an employer refundable tax offset, and an exemption from royalty withholding tax for payments made for the lease of certain shipping vessels.

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Two approaches are described, which aid the selection of the most appropriate procurement arrangements for a building project. The first is a multi-attribute technique based on the National Economic Development Office procurement path decision chart. A small study is described in which the utility factors involved were weighted by averaging the scores of five 'experts' for three hypothetical building projects. A concordance analysis is used to provide some evidence of any abnormal data sources. When applied to the study data, one of the experts was seen to be atypical. The second approach is by means of discriminant analysis. This was found to provide reasonably consistent predictions through three discriminant functions. The analysis also showed the quality criteria to have no significant impact on the decision process. Both approaches provided identical and intuitively correct answers in the study described. Some concluding remarks are made on the potential of discriminant analysis for future research and development in procurement selection techniques.

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Abstract: Texture enhancement is an important component of image processing, with extensive application in science and engineering. The quality of medical images, quantified using the texture of the images, plays a significant role in the routine diagnosis performed by medical practitioners. Previously, image texture enhancement was performed using classical integral order differential mask operators. Recently, first order fractional differential operators were implemented to enhance images. Experiments conclude that the use of the fractional differential not only maintains the low frequency contour features in the smooth areas of the image, but also nonlinearly enhances edges and textures corresponding to high-frequency image components. However, whilst these methods perform well in particular cases, they are not routinely useful across all applications. To this end, we applied the second order Riesz fractional differential operator to improve upon existing approaches of texture enhancement. Compared with the classical integral order differential mask operators and other fractional differential operators, our new algorithms provide higher signal to noise values, which leads to superior image quality.

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Vehicle speed is an important attribute for the utility of a transport mode. The speed relationship between multiple modes of transport is of interest to the traffic planners and operators. This paper quantifies the relationship between bus speed and average car speed by integrating Bluetooth data and Transit Signal Priority data from the urban network in Brisbane, Australia. The method proposed in this paper is the first of its kind to relate bus speed and average car speed by integrating multi-source traffic data in a corridor-based method. Three transferable regression models relating not-in-service bus; in-service bus during peak; and in-service bus during off peak periods with average car are proposed. The models are cross-validated and the interrelationships are significant

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A novel in-cylinder pressure method for determining ignition delay has been proposed and demonstrated. This method proposes a new Bayesian statistical model to resolve the start of combustion, defined as being the point at which the band-pass in-cylinder pressure deviates from background noise and the combustion resonance begins. Further, it is demonstrated that this method is still accurate in situations where there is noise present. The start of combustion can be resolved for each cycle without the need for ad hoc methods such as cycle averaging. Therefore, this method allows for analysis of consecutive cycles and inter-cycle variability studies. Ignition delay obtained by this method and by the net rate of heat release have been shown to give good agreement. However, the use of combustion resonance to determine the start of combustion is preferable over the net rate of heat release method because it does not rely on knowledge of heat losses and will still function accurately in the presence of noise. Results for a six-cylinder turbo-charged common-rail diesel engine run with neat diesel fuel at full, three quarters and half load have been presented. Under these conditions the ignition delay was shown to increase as the load was decreased with a significant increase in ignition delay at half load, when compared with three quarter and full loads.

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Alcohol consumption is enmeshed with Australian culture (Palk, 2008) and the use and misuse of alcohol contributes to considerable health and social harms (Barbor et al., 2010; English et al., 1995; Gutjahr, Gmel, & Rehm, 2001; Palk, 2008; Steenkamp, Harrison, & Allsop, 2002). Despite shifts in the way that alcohol is consumed and how it is used, it has been reported that one-third of all alcohol consumed is done so within licensed premises (Lang, Stockwell, Rydon, & Gamble, 1992). Consequently, licensed premises are over-represented as settings in which alcohol-related harms occur. These harms, particularly those related to violence, are associated with particular licensed premises operating in the night-time economy (Briscoe & Donnelly, 2001b; Chikritzhs, Stockwell, & Masters, 1997; Homel, Tomsen, & Thommeny, 1991; Stockwell, 1997). Police have a role in not only responding to the manifestation of harms, such as crime, injuries, assaults, domestic violence, stealing and sexual offences, but they also have a role in preventing problems, and thereby reducing alcohol and other drug-related harms (Doherty & Roche, 2003). Given the extent of alcohol consumption within licensed premises and the nature and extent of the harms, as well as the lack of opportunity to influence outcomes in other settings (e.g. the home), licensed premises offer police and other stakeholders a significant opportunity to influence positively the reduction of alcoholrelated harm. This research focuses specifically on the police role in policing licensed premises. Primarily, this research aims to investigate the factors which are relevant to why and how police officers respond to alcohol-related incidents inside and outside licensed premises. It examines the attitudes and beliefs of police and assesses their knowledge, capacity and ability to effectively police licensed premises. The research methodology uses three distinct surveys. Each contributes to understanding the motivations and practice of police officers in this important area of harm reduction. Study One involved a survey of police officers within a police district (Brisbane Central District) in Queensland, Australia and used a comprehensive questionnaire involving both quantitative and qualitative techniques. A key research outcome of Study One was the finding that officers had low levels of knowledge of the strategies that are effective in addressing alcohol-related harm both inside and outside licensed premises. Paradoxically, these officers also reported extensive recent experience in dealing with alcohol issues in these locations. In addition, these officers reported that alcohol was a significant contextual factor in the majority of matters to which they responded. Officers surveyed reported that alcohol increased the difficulty of responding to situations and that licensed premises (e.g. nightclubs, licensed clubs and hotels) were the most difficult contexts to police. Those surveyed were asked to self-assess their knowledge of the Liquor Act (Qld), which is the primary legislative authority in Queensland for regulating licensed premises. Surprisingly, well over half of the officers (65%) reported ‘no’ to ‘fair’ knowledge of the Act, despite officers believing that their skill level to police such premises was in the ‘good to very good range’. In an important finding, officers reported greater skill level to police outside licensed premises than inside such premises, indicating that officers felt less capable, from a skill perspective, to operate within the confines of a licensed premise than in the environment immediately outside such premises. Another key finding was that officers reported greater levels of training in responding to situations outside and around licensed premises than to situations inside licensed premises. Officers were also asked to identify the frequency with which they employed specified regulatory enforcement and community-based strategies. Irrespective of the type of response, ‘taking no action’ or passive policing interventions were not favoured by officers. The findings identified that officers favoured taking a range of strategies (sending home, releasing into the custody of friends, etc.) in preference to arrest. In another key finding, officers generally reported their support for operational stakeholder partnership approaches to policing licensed premises. This was evidenced by the high number of officers (over 90%) reporting that there should be shared responsibility for enforcing the provisions of the Liquor Act. Importantly, those surveyed also identified the factors which constrain or prevent them from policing licensed premises. Study Two involved interviewing a small but comprehensive group (n=11) of senior managers from within the Queensland Police Service (QPS) who have responsibility for setting operational and strategic policy. The aim of this study was to examine the attitudes, perceptions and influence that senior officers (at the strategy and policy-setting level) had on the officers at the operational level. This qualitative study was carried out using a purposive sampling (Denzin & Lincoln, 2005; Guba & Lincoln, 1989), focused interview and thematic analytic approach. The interview participants were drawn from three tiers of management at district, regional as well as the whole-of-organisational level. The first key theme emerging from the study related to role, in terms of both the QPS broader organisational role, and the individual officer role with respect to the policing of licensed premises. For the QPS organisational role, participants at all three strategic levels had a high degree of congruity as to the organisations service role; that is, to enhance public safety. With respect to participants’ beliefs as to whether police officers have knowledge and understanding of their individual roles concerning licensed premises (as opposed to the QPS role), participants reported most commonly that officers had a reasonable to clear understanding of their role. Participant comments also were supportive of the view that officers operating in the research area, Brisbane Central District (BCD), had a clearer understanding of their role than police operating in other locations. The second key theme to emerge identified a disparity between the knowledge and capability of specialist police, compared with general duties police, to police licensed premises. In fact, a number of the responses to a variety of questions differentiated specialist and general police in a range of domains. One such example related to the clarity of understanding of officer role. Participants agreed that specialist police (Liquor Enforcement & Proactive Strategies [LEAPS] officers) had more clarity of understanding in terms of their role than generalist police. Participants also were strongly of the opinion that specialist police had higher skill levels to deal with issues both inside and outside licensed premises. Some participants expressed the view that general duty police undertook purely response-related activities, or alternatively, dealt with lower order matters. Conversely, it was viewed that specialist police undertook more complex tasks because of their higher levels of knowledge and skill. The third key theme to emerge concerned the identification of barriers that serve to restrict or prevent police officers from policing licensed premises. Participant responses strongly indicated that there was a diversity of resourcing barriers that restrict police from undertaking their roles in licensed premises. Examples of such barriers were the lack of police and the low ratio of police to patrons, available officer time, and lack of organisational investment in skills and knowledge acquisition. However, some participants indicated that police resourcing in the BCD was appropriate and officers were equipped with sufficient powers (policy and legislation). Again, the issue of specialist police was raised by one participant who argued that increasing the numbers of specialist police would ameliorate the difficulties for police officers policing licensed premises. The fourth and last key theme to emerge from Study Two related to the perception of senior officers regarding the opportunity and capability of officers to leverage off external partnerships to reduce harms inside and outside licensed premises. Police working in partnership in BCD was seen as an effective harm reduction strategy and strongly supported by the participants. All participants demonstrated a high degree of knowledge as to who these partners were and could identify those government, non-government and community groups precisely. Furthermore, the majority of participants also held strong views that the partnerships were reasonably effective and worked to varying degrees depending on the nature of the partnership and issues such as resourcing. These senior officers identified better communication and coordination as factors that could potentially strengthen these partnerships. This research finding is particularly important for senior officers who have the capacity to shape the policy and strategic direction of the police service, not only in Queensland but throughout Australasia. Study Three examined the perceptions of those with links to the broader liquor industry (government, non-government and community but exclusive of police) concerning their understanding of the police role and the capacity of police to reduce alcohol-related harm inside and outside licensed premises, and their attitudes towards police. Participants (n=26) surveyed represented a range of areas including the liquor industry, business represenatives and government representatives from Queensland Fire and Rescue Service, Queensland Ambulance Service, Brisbane City Council and Queensland Health. The first key theme to emerge from Study Three related to participant understanding of the QPS organisational role, and importantly, individual officer role in policing licensed premises. In terms of participant understanding of the QPS role there was a clear understanding by the majority of participants that the police role was to act in ways consistent with the law and to otherwise engage in a range of enforcement-related activities. Participants saw such activities falling into two categories. The first category related to reactive policing, which included actions around responding to trouble in licensed premises, monitoring crowd controllers and removing trouble-makers. In the second category, proactive approaches, participants identified the following activities as consistent with that approach: early intervention with offenders, support of licensed premises operators and high visibility policing. When participants were asked about their understanding of individual officer roles in the policing of licensed premises, a range of responses were received but the consistent message that emerged was that there is a different role to be played by general duty (uniformed) police compared to specialist (LEAPS Unit) police, which reflects differences in knowledge, skill and capability. The second key theme that emerged from the data related to the external participants’ views of the knowledge and capability of specialist police, compared with general duty police, to police licensed premises. As noted in the first key theme, participants were universally of the view that the knowledge, skill and capability of police in specialist units (LEAPS Unit) was at a higher level than that of general duty police. Participants observed that these specialist officers were better trained than their colleagues in generalist areas and were therefore better able to intervene knowledgeably and authoritatively to deal with problems and issues as they emerged. Participants also reported that officers working within BCD generally had a positive attitude to their duties and had important local knowledge that they could use in the resolution of alcohol-related issues. Participants also commented on the importance of sound and effective QPS leadership, as well as the quality of the leadership in BCD. On both these measures, there was general consensus from participants, who reported positively on the importance and effectiveness of such leadership in BCD. The third key theme to emerge from Study Three concerned the identification of barriers that serve to restrict or prevent police officers from policing licensed premises. Overwhelmingly, external participants reported the lack of human resources (i.e. police officers) as the key barrier. Other resourcing limitations, such as available officer time, police computer systems, and the time taken to charge offenders, were identified as barriers. Some participants identified barriers in the liquor industry such as ‘dodgy operators’ and negative media attention as limitations. Other constraints to emerge related to government and policy barriers. These were reflected in comments about the collection by government of fees from licensees and better ‘powers’ for police to deal with offenders. The fourth and final key theme that emerged from Study Three related to the opportunities for and capability of police to leverage off external partnerships to reduce harms inside and outside licensed premises. Not surprisingly, participants had a comprehensive knowledge of a broad range of stakeholders, from a diversity of contexts, influential in addressing issues in licensed premises. Many participants reported their relationships with the police and other stakeholders as effective, productive and consistent with the objectives of partnering to reduce alcohol-related harm. On the other hand, there were those who were concerned with their relationship with other stakeholders, particularly those with a compliance function (e.g. Office of Liquor & Gaming Regulation [OLGR]). The resourcing limitations of partners and stakeholders were also raised as an important constraining factor in fulfilling the optimum relationship. Again, political issues were mentioned in terms of the impact on partnerships, with participants stating that there is at times political interference and that politicians complicate the relationships of stakeholders. There are some significant strengths with respect to the methodology of this research. The research is distinguished from previous work in that it examines these critical issues from three distinct perspectives (i.e. police officer, senior manager and external stakeholder). Other strengths relate to the strong theoretical framework that guides and informs the research. There are also some identified limitations, including the subjective nature of self-report data as well as the potential for bias by the author, which was controlled for using a range of initiatives. A further limitation concerns the potential for transferability and generalisability of the findings to other locations given the distinctive nature of the BCD. These limitations and issues of transferability are dealt with at length in the thesis. Despite a growing body of literature about contextual harms associated with alcohol, and specific research concerning police intervention in such contextual harms, there is still much to learn. While research on the subject of police engaging in alcohol-related incidents has focused on police behaviours and strategies in response to such issues, there is a paucity of research that focuses on the knowledge and understanding of officers engaged in such behaviours and practices. Given the scarcity of research dealing with the knowledge, skills and attitudes of police officers responding to harms inside and outside licensed premises, this research contributes significantly to what is a recent and growing body of research and literature in the field. The research makes a practical contribution to police agencies’ understanding of officer knowledge and police practice in ways that have the potential to shape education and training agendas, policy approaches around generalist versus specialist policing, strategic and operational strategy, as well as partnership engagements. The research also makes a theoretical contribution given that the research design is informed by the Three Circle

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As highlighted by previous work in Normal Accident Theory1 and High Reliability Organisations, 2 the ability of a system to be flexible is of critical importance to its capability to prepare for, respond to, and recover from disturbance and disasters. This paper proposes that the research into ‘edge organisations’3 and ‘agility’4 is a potential means to operationalise components that embed high reliable traits in the management and oversight of critical infrastructure systems. Much prior work has focused on these concepts in a military frame whereas the study reported on here examines the application of these concepts to aviation infrastructure, specifically, a commercial international airport. As a commercial entity functions in a distinct manner from a military organisation this study aims to better understand the complementary and contradictory components of the application of agility work to a commercial context. Findings highlight the challenges of making commercial operators of infrastructure systems agile as well as embedding traits of High Reliability in such complex infrastructure settings.

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Critical road infrastructure (such as tunnels and overpasses) is of major significance to society and constitutes major components of interdependent, ‘systems and networks’. Failure in critical components of these wide area infrastructure systems can often result in cascading disturbances with secondary and tertiary impacts - some of which may become initiating sources of failure in their own right, triggering further systems failures across wider networks. Perrow1) considered the impact of our increasing use of technology in high-risk fields, analysing the implications on everyday life and argued that designers of these types of infrastructure systems cannot predict every possible failure scenario nor create perfect contingency plans for operators. Challenges exist for transport system operators in the conceptualisation and implementation of response and subsequent recovery planning for significant events. Disturbances can vary from reduced traffic flow causing traffic congestion throughout the local road network(s) and subsequent possible loss of income to businesses and industry to a major incident causing loss of life or complete loss of an asset. Many organisations and institutions, despite increasing recognition of the effects of crisis events, are not adequately prepared to manage crises2). It is argued that operators of land transport infrastructure are in a similar category of readiness given the recent instances of failures in road tunnels. These unexpected infrastructure failures, and their ultimately identified causes, suggest there is significant room for improvement. As a result, risk profiles for road transport systems are often complex due to the human behaviours and the inter-mix of technical and organisational components and the managerial coverage needed for the socio-technical components and the physical infrastructure. In this sense, the span of managerial oversight may require new approaches to asset management that combines the notion of risk and continuity management. This paper examines challenges in the planning of response and recovery practices of owner/operators of transport systems (above and below ground) in Australia covering: • Ageing or established infrastructure; and • New-build infrastructure. With reference to relevant international contexts this paper seeks to suggest options for enhancing the planning and practice for crisis response in these transport networks and as a result support the resilience of Critical Infrastructure.