976 resultados para technical school


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Organizational transformations reliant on successful ICT system developments (continue to) fail to deliver projected benefits even when contemporary governance models are applied rigorously. Modifications to traditional program, project and systems development management methods have produced little material improvement to successful transformation as they are unable to routinely address the complexity and uncertainty of dynamic alignment of IS investments and innovation. Complexity theory provides insight into why this phenomenon occurs and is used to develop a conceptualization of complexity in IS-driven organizational transformations. This research-in-progress aims to identify complexity formulations relevant to organizational transformation. Political/power based influences, interrelated business rules, socio-technical innovation, impacts on stakeholders and emergent behaviors are commonly considered as characterizing complexity while the proposed conceptualization accommodates these as connectivity, irreducibility, entropy and/or information gain in hierarchically approximation and scaling, number of states in a finite automata and/or dimension of attractor, and information and/or variety.

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This paper merges the analysis of a case history and the simplified theoretical model related to a rather singular phenomenon that may happen in rotating machinery. Starting from the first, a small industrial steam turbine experienced a very strange behavior during megawatt load. When the unit was approaching the maximum allowed power, the temperature of the babbitt metal of the pads of the thrust bearing showed constant increase with an unrecoverable drift. Bearing inspection showed that pad trailing edge had the typical aspect of electrical pitting. This kind of damage was not reparable and bearing pads had to replaced. This problem occurred several times in sequence and was solved only by adding further ground brushes to the shaft-line. Failure analysis indicated electrodischarge machining as the root fault. A specific model, able to take into consideration the effect of electrical pitting and loading capacity decreasing as a consequence of the damage of the babbitt metal, is proposed in the paper and shows that the phenomenon causes the irretrievable failure of the thrust bearing.

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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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Diagnostics is based on the characterization of mechanical system condition and allows early detection of a possible fault. Signal processing is an approach widely used in diagnostics, since it allows directly characterizing the state of the system. Several types of advanced signal processing techniques have been proposed in the last decades and added to more conventional ones. Seldom, these techniques are able to consider non-stationary operations. Diagnostics of roller bearings is not an exception of this framework. In this paper, a new vibration signal processing tool, able to perform roller bearing diagnostics in whatever working condition and noise level, is developed on the basis of two data-adaptive techniques as Empirical Mode Decomposition (EMD), Minimum Entropy Deconvolution (MED), coupled by means of the mathematics related to the Hilbert transform. The effectiveness of the new signal processing tool is proven by means of experimental data measured in a test-rig that employs high power industrial size components.

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Design of hydraulic turbines has often to deal with hydraulic instability. It is well-known that Francis and Kaplan types present hydraulic instability in their design power range. Even if modern CFD tools may help to define these dangerous operating conditions and optimize runner design, hydraulic instabilities may fortuitously arise during the turbine life and should be timely detected in order to assure a long-lasting operating life. In a previous paper, the authors have considered the phenomenon of helical vortex rope, which happens at low flow rates when a swirling flow, in the draft tube conical inlet, occupies a large portion of the inlet. In this condition, a strong helical vortex rope appears. The vortex rope causes mechanical effects on the runner, on the whole turbine and on the draft tube, which may eventually produce severe damages on the turbine unit and whose most evident symptoms are vibrations. The authors have already shown that vibration analysis is suitable for detecting vortex rope onset, thanks to an experimental test campaign performed during the commissioning of a 23 MW Kaplan hydraulic turbine unit. In this paper, the authors propose a sophisticated data driven approach to detect vortex rope onset at different power load, based on the analysis of the vibration signals in the order domain and introducing the so-called "residual order spectrogram", i.e. an order-rotation representation of the vibration signal. Some experimental test runs are presented and the possibility to detect instability onset, especially in real-time, is discussed.

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The progress of technology has led to the increased adoption of energy monitors among household energy consumers. While the monitors available on the market deliver real-time energy usage feedback to the consumer, the form of this data is usually unengaging and mundane. Moreover, it fails to address consumers with different motivations and needs to save and compare energy. This master‟s thesis project presents a study that seeks to inform design guidelines for differently motivated energy consumers. The focus of the research is on comparative feedback supported by a community of energy consumers. In particular, the discussed comparative feedback types are explanatory comparison, temporal self-comparison, norm comparison, one-on-one comparison and ranking, whereby the last three support exploring the potential of socialising energy-related feedback in social networking sites, such as Facebook. These feedback types were integrated in EnergyWiz – a mobile application that enables users to compare with their past performance, neighbours, contacts from social networking sites and other EnergyWiz users. The application was developed through a theory-driven approach and evaluated in personal, semi-structured interviews which provided insights on how motivation-related comparative feedback should be designed. It was also employed in expert focus group discussions which resulted in defining opportunities and challenges before mobile, social energy monitors. The findings have unequivocally shown that users with different motivations to compare and to conserve energy have different preferences for comparative feedback types and design. It was established that one of the most influential factors determining design factors is the people users compare to. In addition, the research found that even simple communication strategies in Facebook, such as wall posts and groups can contribute to engagement with energy conservation practices. The concept of mobility of the application was evaluated as positive since it provides place and time-independent access to the energy consumption data.

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The National Curriculum is an innovation in Australian schooling history and is likely to have a widespread and long-term impact on schools, teachers and students. This research used theoretical frameworks informed by Leithwood (1994) and Fullan (2007), and concepts related to innovation, to contribute to an understanding that may support a better understanding of teachers' perceptions when leading curriculum change such as a National Curriculum in schools. This research concludes that teachers who participated in the research demonstrated that their perceptions of a National Curriculum implementation are influenced by their perceptions of school leadership. Specifically, teachers with positive perceptions of their Principal's leadership also had positive perceptions of their capacity to implement the new National Curriculum.

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Bacterial siderophores are a group of chemically diverse, virulence-associated secondary metabolites whose expression exerts metabolic costs. A combined bacterial genetic and metabolomic approach revealed differential metabolomic impacts associated with biosynthesis of different siderophore structural families. Despite myriad genetic differences, the metabolome of a cheater mutant lacking a single set of siderophore biosynthetic genes more closely approximate that of a nonpathogenic K12 strain than its isogenic, uropathogen parent strain. Siderophore types associated with greater metabolomic perturbations are less common among human isolates, suggesting that metabolic costs influence success in a human population. Although different siderophores share a common iron acquisition function, our analysis shows how a metabolomic approach can distinguish their relative metabolic impacts in E.coli.

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Agile learning spaces have the potential to afford flexible and innovative pedagogic practice. However there is little known about the experiences of teachers and learners in newly designed learning spaces, and whether the potential for reimagined pedagogies is being realised. This paper uses data from a recent study into the experiences of teacher-librarians, teachers, students and leaders of seven Queensland school libraries built with Building the Education Revolution (BER) funding, to explore the question, “how does the physical environment of school libraries influence pedagogic practices?” This paper proposes that teachers explored new pedagogies within the spaces when there was opportunity for flexibility and experimentation and the spaces sufficiently supported their beliefs about student learning. The perspectives of a range of library users were gathered through an innovative research design incorporating student drawings, videoed library tours and reflections, and interviews. The research team collected qualitative data from school libraries throughout 2012. The libraries represented a variety of geographic locations, socioeconomic conditions and both primary and secondary campuses. The use of multiple data sources, and also the perspectives of the multiple researchers who visited the sites and then coded the data, enabled complementary insights and synergies to emerge. Principles of effective teacher learning that can underpin school wide learning about the potential for agile learning spaces to enhance student learning, are identified. The paper concludes that widespread innovative use of the new library spaces was significantly enhanced when the school leadership fostered whole school discussions about the type of learning the spaces might provoke. This research has the potential to inform school designers, teachers and teacher-librarians to make the most of the transformative potential of next generation learning spaces.

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The use of Wireless Sensor Networks (WSNs) for Structural Health Monitoring (SHM) has become a promising approach due to many advantages such as low cost, fast and flexible deployment. However, inherent technical issues such as data synchronization error and data loss have prevented these distinct systems from being extensively used. Recently, several SHM-oriented WSNs have been proposed and believed to be able to overcome a large number of technical uncertainties. Nevertheless, there is limited research examining effects of uncertainties of generic WSN platform and verifying the capability of SHM-oriented WSNs, particularly on demanding SHM applications like modal analysis and damage identification of real civil structures. This article first reviews the major technical uncertainties of both generic and SHM-oriented WSN platforms and efforts of SHM research community to cope with them. Then, effects of the most inherent WSN uncertainty on the first level of a common Output-only Modal-based Damage Identification (OMDI) approach are intensively investigated. Experimental accelerations collected by a wired sensory system on a benchmark civil structure are initially used as clean data before being contaminated with different levels of data pollutants to simulate practical uncertainties in both WSN platforms. Statistical analyses are comprehensively employed in order to uncover the distribution pattern of the uncertainty influence on the OMDI approach. The result of this research shows that uncertainties of generic WSNs can cause serious impact for level 1 OMDI methods utilizing mode shapes. It also proves that SHM-WSN can substantially lessen the impact and obtain truly structural information without having used costly computation solutions.

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Two poems in journal Axon. 2013 Issue 4.

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We present a review of literature from the fields of gerontology, gerontechnology, HCI and government policy that deals with social and technical solutions for the ageing population. We highlight common assumptions about ageing people, which we argue are still embedded in much of the research related to the domain of ageing. This paper challenges six common assumptions across four broad themes that we identified in the literature. It aims to provide a reminder and resource for designers to eschew assumptions during designing technology for 'older' users.

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The demands and responsibilities placed on schools in contemporary education systems are vast. However, with growing obesity levels and physical inactivity, the prevention of chronic disease has focused on youth populations, with schools playing the focal educative asset in this strategy. Parents play a decisive role in their child’s educational setting, and as fee and tax payers, are ultimately a consumer. Parents (82 males and 208 females) of secondary school children were recruited from three private (n=151) and two government schools (n=150) in Brisbane, Australia. The mean (standard deviation) age was 44.57 (6.21) years. Participants responded to a series of questions about physical activity at their child’s school, in addition to completing the International Physical Activity Questionnaire. Data were analysed using descriptive statistics, frequency distributions and logistic regressions. Parents were deemed sufficiently physically active if they participated in at least 150 minutes of moderate-to-vigorous physical activity per week. Overall, 83 (59.7%) parents from private and 60 (50.8%) parents from government schools were deemed sufficiently physically active. Concerning whether physical activity promotion should be a priority at their child’s school, 111 (73.5%) parents from private schools either agreed or strongly agreed, as opposed to 97 (64.7%) parents from government schools. Logistic regressions indicated that the concept of physical activity promotion being prioritised at schools was dependent on whether the child attended a private school (OR =1.34, z = 2.30, p = 0.02), and whether the participant was sufficiently active (OR =.71, z = -2.48, p = 0.01). Physical activity promotion within schools may provide substantial future benefits on a population scale. The demands on schools may need to be addressed to meet the needs of students and the desires of their parents.