957 resultados para Multi-Platform


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This thesis presents an analysis of the resource allocation problem in Orthogonal Frequency Division Multiplexing based multi-hop wireless communications systems. The study analyzed the tractable nature of the problem and designed several heuristic and fairness-aware resource allocation algorithms. These algorithms are fast and efficient and therefore can improve power management in wireless systems significantly.

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This thesis investigates condition monitoring (CM) of diesel engines using acoustic emission (AE) techniques. The AE signals recorded from a small size diesel engine are mixtures of multiple sources from multiple cylinders. Thus, it is difficult to interpret the information conveyed in the signals for CM purposes. This thesis develops a series of practical signal processing techniques to overcome this problem. Various experimental studies conducted to assess the CM capabilities of AE analysis for diesel engines. A series of modified signal processing techniques were proposed. These techniques showed promising results of capability for CM of multiple cylinders diesel engine using multiple AE sensors.

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The small and medium enterprise (SME) sector has been the major source of well-being and employment opportunities in regional Australia. Consequently, fostering the innovative capacity of SMEs in regions that are struggling to grow their economies and distribute the growth fairly while not degrading the environment has never been more important. While SMEs generally face more uncertainties in relation to resources (e.g. financial, human and social capital) when compared to larger businesses, collaborative, cuttingedge mechanisms to enhance innovation capabilities of regional SMEs are lacking. This paper responds to this gap and proposes a Living Laboratory – an open, multi-disciplinary and multi-stakeholder action research platform where innovations can be co-created, tested and evaluated in the every-day environment of SMEs – as a way to strengthen the SME sector in regional Australia.

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Multi-Microgrids (MMGs) have been proposed to connect distributed generators (DG), microgrids (MG), and medium-voltage (MV) loads with the distribution system. A flexible protection scheme that enables an islanded MMG to continue operation during fault conditions is yet to be developed. In this paper, a protection scheme for an islanded MMG that utilises MG controllers and communication links is proposed. The MMG model used includes two MGs connected to the distribution system. Each MG consists of diesel, wind, and photovoltaic (PV) microsources. The effectiveness of the proposed protection scheme is evaluated by simulation.

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This thesis presents a multi-criteria optimisation study of group replacement schedules for water pipelines, which is a capital-intensive and service critical decision. A new mathematical model was developed, which minimises total replacement costs while maintaining a satisfactory level of services. The research outcomes are expected to enrich the body of knowledge of multi-criteria decision optimisation, where group scheduling is required. The model has the potential to optimise replacement planning for other types of linear asset networks resulting in bottom-line benefits for end users and communities. The results of a real case study show that the new model can effectively reduced the total costs and service interruptions.

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Association rule mining is one technique that is widely used when querying databases, especially those that are transactional, in order to obtain useful associations or correlations among sets of items. Much work has been done focusing on efficiency, effectiveness and redundancy. There has also been a focusing on the quality of rules from single level datasets with many interestingness measures proposed. However, with multi-level datasets now being common there is a lack of interestingness measures developed for multi-level and cross-level rules. Single level measures do not take into account the hierarchy found in a multi-level dataset. This leaves the Support-Confidence approach, which does not consider the hierarchy anyway and has other drawbacks, as one of the few measures available. In this chapter we propose two approaches which measure multi-level association rules to help evaluate their interestingness by considering the database’s underlying taxonomy. These measures of diversity and peculiarity can be used to help identify those rules from multi-level datasets that are potentially useful.

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The selection of optimal camera configurations (camera locations, orientations, etc.) for multi-camera networks remains an unsolved problem. Previous approaches largely focus on proposing various objective functions to achieve different tasks. Most of them, however, do not generalize well to large scale networks. To tackle this, we propose a statistical framework of the problem as well as propose a trans-dimensional simulated annealing algorithm to effectively deal with it. We compare our approach with a state-of-the-art method based on binary integer programming (BIP) and show that our approach offers similar performance on small scale problems. However, we also demonstrate the capability of our approach in dealing with large scale problems and show that our approach produces better results than two alternative heuristics designed to deal with the scalability issue of BIP. Last, we show the versatility of our approach using a number of specific scenarios.

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Diagnostics of rolling element bearings have been traditionally developed for constant operating conditions, and sophisticated techniques, like Spectral Kurtosis or Envelope Analysis, have proven their effectiveness by means of experimental tests, mainly conducted in small-scale laboratory test-rigs. Algorithms have been developed for the digital signal processing of data collected at constant speed and bearing load, with a few exceptions, allowing only small fluctuations of these quantities. Owing to the spreading of condition based maintenance in many industrial fields, in the last years a need for more flexible algorithms emerged, asking for compatibility with highly variable operating conditions, such as acceleration/deceleration transients. This paper analyzes the problems related with significant speed and load variability, discussing in detail the effect that they have on bearing damage symptoms, and propose solutions to adapt existing algorithms to cope with this new challenge. In particular, the paper will i) discuss the implication of variable speed on the applicability of diagnostic techniques, ii) address quantitatively the effects of load on the characteristic frequencies of damaged bearings and iii) finally present a new approach for bearing diagnostics in variable conditions, based on envelope analysis. The research is based on experimental data obtained by using artificially damaged bearings installed on a full scale test-rig, equipped with actual train traction system and reproducing the operation on a real track, including all the environmental noise, owing to track irregularity and electrical disturbances of such a harsh application.

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This body of photographic work has been created to firstly, explore a new approach to practice-led research that uses an “action genre” approach to reflective practice (Lemke) and secondly, to visually explore human interaction with the fundamental item in life - water. The first of these is based on the contention that to understand the meanings inherent in photographs we cannot look merely at the end result. It is essential to keep looking at the actions of practitioners, and the influences upon them, to determine how external influences affect the meaning potential of editorial photographs (Grayson, 2012). WATER therefore, provides an ideal platform to reflect upon the actions and influences involved in creating work within the photographic genre of photojournalism. It enables this practitioner to reflect on each stage of production to gain a better understanding of how external influences impact the narrative potential within images created. There are multi-faceted influences experienced by photographers who are creating images that, in turn, are part of constructing and presenting the narrative potential of editorial photographs. There is an important relationship between professional photographers and the technical, cultural, economic and institutional forces that impinge upon all stages of production and publication. What results is a greater understanding of technical, cultural, economic and institutional forces that impinge upon all stages of production and publication. Therefore, to understand the meanings inherent in photographs within WATER, I do not look merely at the end result. It provides a case study looking at my actions in the filed, and the influences upon me, to determine how external influences affect the meaning potential of these photographs (Grayson, 2012). As a result, this project adds to the body of scholarship around the definition of Photojournalism, how it has adapted to the current media environment and provides scope for further research into emerging new genres within editorial photography, such as citizen photojournalism. Concurrently, the photographs themselves were created to visually explore how there remains a humanistic desire to interact with the natural form of water even while living a modern cosmopolitan life around it. Taking a photojournalistic approach to exploring this phenomenon, the images were created by “capturing moments as they happened” with no posing or setting up of images. This serendipitous approach to the photographic medium provides the practitioner with at least an attempt to direct the subjectivity contained explicitly in photographs. What results is a series of images that extend the visual dialogue around the role of water within modern humanistic lifestyles and how it remains an integral part of our society’s behaviors. It captures important moments that document this relationship at this time of modern development. The resulting works were exhibited and published as part of the Head On Photo Festival, Australia's largest photo festival and the world's second largest festival in Sydney 20-24 May 2013. The WATER series of images were curated by three Magnum members; Ian Berry, Eli Reed and Chris Steele-Perkins. Magnum is a highly regarded international photographic co-operative with editorial offices in New York, London, Paris and Tokyo. There was a projection of the works as part of the official festival programme, presented to both members of the public and Sydney’s photography professionals. In addition, a sample of images from the WATER series was chosen for inclusion in the Magnum-published hardcover book. References Grayson, Louise. 2012. “Editorial photographs and patterns of practice.” Journalism Practice. Accessed: http://www.tandfonline.com/doi/abs/10.1080/17512786.2012.726836#.UbZN-L--1RQ Lemke, Jay. 1995. Textual Politics: Discourse and Social Dynamics. London: Taylor & Francis.

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We report on an alternative OCGM interface for a bulletin board, where a user can pin a note or a drawing, and actually shares contents. Exploiting direct and continuous manipulations, opposite to discrete gestures, to explore containers, the proposed interface supports a more natural and immediate interaction. It manages also the presence of different simultaneous users, allowing for the creation of local multimedia contents, the connection to social networks, providing a suitable working environment for cooperative and collaborative tasks in a multi-touch setup, such as touch-tables, interactive walls or multimedia boards

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This paper conceptualizes and defines knowledge governance (KG) in project-based organizations (PBOs). Two key contributions towards a multi-faceted view of KG and an understanding of KG in PBOs are advanced, as distinguished from knowledge management and organizational learning concepts. The conceptual framework addresses macro- and micro-level elements of KG and their interaction. Our definition of KG in PBOs highlights the contingent nature of KG processes in relation to their organizational context. These contributions provide a novel platform for understanding KG in PBOs.

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This paper presents large, accurately calibrated and time-synchronised datasets, gathered outdoors in controlled environmental conditions, using an unmanned ground vehicle (UGV), equipped with a wide variety of sensors. It discusses how the data collection process was designed, the conditions in which these datasets have been gathered, and some possible outcomes of their exploitation, in particular for the evaluation of performance of sensors and perception algorithms for UGVs.

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Joint venture design teams are formed to combine resources and expertise in order to secure multi-discipline engineering design services on major projects. Bringing together resources from two ordinarily competing companies to form one joint team is however challenging as each parent company brings to the project its own organisational culture, processes and team attitudes. This study examined the factors that impact on forming a successful joint venture project team. Three critical areas were identified from an extensive literature review; Joint Venture Arrangements, Parent Companies and Forming the Team; and a survey was conducted with professionals who have worked in joint venture project teams in the Australian building industry in order to identify factors that affected successful joint venture team formation, and the common lessons learnt. This study reinforced the importance of three key criteria - trust, commitment and compatibility - for partner alignment. The results also identified four key lessons learnt which included; selecting the right resources, enabling a collaborative working environment by way of project office, implementing an independent Joint Venture Manager, and allocating work which is best for project with fees reflecting risk where risk is disproportionate.