995 resultados para Impulsive semidynamical systems


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Fire safety design of buildings is essential to safeguard lives and minimize the loss of damage to properties. Light-weight cold-formed steel channel sections along with fire resistive plasterboards are used to construct light gauge steel frame floor systems to provide the required fire resistance rating. However, simply adding more plasterboard layers is not an efficient method to increase FRR. Hence this research focuses on using joists with improved joist section profiles such as hollow flange sections to increase the structural capacity of floor systems under fire conditions and thus their FRR. In this research, the structural and thermal behaviour of LSF floor systems made of LiteSteel Beams with different plasterboard and insulation configurations was investigated using four full scale tests under standard fires. Based on the ultimate failure load of the floor joist at ambient temperature, transient state fire tests were conducted for different Load Ratios. These fire tests showed that the new LSF floor system has improved the FRR well above that of those made of lipped channel sections. The joist failure was predominantly due to local buckling of LSB compression flanges near mid-span with severe yielding of tension flanges. Fire tests have provided valuable structural and thermal performance data of tested floor systems that included time-temperature profiles, and failure times and temperatures. Average failure temperatures of LSB joists and reduced yield strengths were used to predict their ultimate moment capacities, which were compared with corresponding test capacities. This allowed an assessment in relation to the accuracy of current design rules for steel joists at elevated temperatures. This paper presents the details of full scale fire tests of LSF floor systems made of LSB joists with different plasterboard and insulation configurations and their results along with some important findings.

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Organizational and technological systems analysis and design practices such as process modeling have received much attention in recent years. However, while knowledge about related artifacts such as models, tools, or grammars has substantially matured, little is known about the actual tasks and interaction activities that are conducted as part of analysis and design acts. In particular, key role of the facilitator has not been researched extensively to date. In this paper, we propose a new conceptual framework that can be used to examine facilitation behaviors in process modeling projects. The framework distinguishes four behavioral styles in facilitation (the driving engineer, the driving artist, the catalyzing engineer, and the catalyzing artist) that a facilitator can adopt. To distinguish between the four styles, we provide a set of ten behavioral anchors that underpin facilitation behaviors. We also report on a preliminary empirical exploration of our framework through interviews with experienced analysts in six modeling cases. Our research provides a conceptual foundation for an emerging theory for describing and explaining different behaviors associated with process modeling facilitation, provides first preliminary empirical results about facilitation in modeling projects, and provides a fertile basis for examining facilitation in other conceptual modeling activities.

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The present study deals with two dimensional, numerical simulation of railway track supporting system subjected to dynamic excitation force. Under plane strain condition, the coupled finite-infinite elements to represent the near and far field stress distribution and thin layer interface element was employed to model the interfacial behavior between sleepers and ballast. To account for the relative debonding, slipping and crushing that could take place in the contact area between the sleepers and ballast, modified Mohr-Coulomb criterion was adopted. Furthermore an attempt has been made to consider the elasto-plastic material non-linearity of the railway track supporting media by employing different constitutive models to represent steel, concrete and supporting materials. Based on the proposed physical and constitutive modeling a code has been developed for dynamic loads. The applicability of the developed F.E code has been demonstrated by analyzing a real railway supporting structure.

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This paper investigates how community based media organisations are co-creative storytelling institutions, and how they learn to disseminate knowledge in a social learning system. Organisations involved in story co-creation are learning to create in fluid environments.They are project based, with a constant turnover of volunteers or staff. These organisations have to meet the needs of their funding bodies and their communities to remain sustainable. Learning is seen as dialogical, and this is also reflected in the nature of storytelling itself. These organisations must learn to meet the needs of their communities, who in turn learn from the organisation’s expertise in a facilitated setting. This learning is participatory and collaborative, and is often a mix of virtual and offline interaction. Such community-based organisations sit in the realm of a hybrid-learning environment; they are neither a formal educational institution like a college, nor do their volunteers produce outcomes in a professional capacity. Yet, they must maintain a certain level of quality outcomes from their contributors to be of continued value in their communities. Drawing from a larger research study, one particular example is that of the CitizenJ project. CitizenJ is hosted by a state cultural centre, and partnered with publishing partners in the community broadcasting sector. This paper explores how this project is a Community of Practice, and how it promotes ethical and best practice, meets contributors’ needs, emphasises the importance of facilitation in achieving quality outcomes, and the creation of projects for wider community and public interest.

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Discounted Cumulative Gain (DCG) is a well-known ranking evaluation measure for models built with multiple relevance graded data. By handling tagging data used in recommendation systems as an ordinal relevance set of {negative,null,positive}, we propose to build a DCG based recommendation model. We present an efficient and novel learning-to-rank method by optimizing DCG for a recommendation model using the tagging data interpretation scheme. Evaluating the proposed method on real-world datasets, we demonstrate that the method is scalable and outperforms the benchmarking methods by generating a quality top-N item recommendation list.

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This paper reviews a variety of advanced signal processing algorithms that have been developed at the University of Southampton as part of the Prometheus (PROgraMme for European Traffic flow with Highest Efficiency and Unprecedented Safety) research programme to achieve an intelligent driver warning system (IDWS). The IDWS includes: visual detection of both generic obstacles and other vehicles, together with their tracking and identification, estimates of time to collision and behavioural modelling of drivers for a variety of scenarios. These application areas are used to show the applicability of neurofuzzy techniques to the wide range of problems required to support an IDWS, and for future fully autonomous vehicles.

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In this paper we discuss some preliminary results of an ethnographic study focused on the ways money and financial issues are collaboratively handled within families. Families develop ‘systems’ or methods through which they organize and manage their everyday financial activities. These systems not only organize everyday family finances, but represent and shape family relationships. Through analysis of our ethnographic field study data, we develop four types of financial systems that we observed in the field: banking arrangements, physical hubs, goal-oriented systems and spatio-temporal organization. In this paper, we discuss examples of these systems and their implications for designing tools to support household financial practices.

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This important new book draws lessons from a large-scale initiative to bring about the improvement of an urban education system. Written from an insider perspective by an internationally recognized researcher, it presents a new way of thinking about system change. This builds on the idea that there are untapped resources within schools and the communities they serve that can be mobilized in order to transform schools from places that do well for some children so that they can do well for many more. Towards Self-improving School Systems presents a strategic framework that can help to foster new, more fruitful working relationships: between national and local government; within and between schools; and between schools and their local communities. What is distinctive in the approach is that this is mainly led from within schools, with senior staff having a central role as system leaders. The book will be relevant to a wide range of readers throughout the world who are concerned with the strengthening of their national educational systems, including teachers, school leaders, policy makers and researchers. The argument it presents is particularly important for the growing number of countries where increased emphasis on school autonomy, competition and choice is leading to fragmentation within education provision.

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This review provides details on the role of Geographical Information Systems (GIS) in current dengue surveillance systems and focuses on the application of open access GIS technology to emphasize its importance in developing countries, where the dengue burden is greatest. It also advocates for increased international collaboration in transboundary disease surveillance to confront the emerging global challenge of dengue.

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A number of international human rights frameworks protect the rights of young people in contact with the criminal justice system in states parties, including Australia. These frameworks inform youth justice policy in Australia’s jurisdictions. While the frameworks protect young people’s right to non-discrimination on the grounds of ‘race’, religion and political opinion, the rights of young people to non-discrimination on the grounds of sexuality and gender diversity are not explicitly protected. This is problematic given that lesbian, gay, bisexual, trans, intersex and queer (LGBTIQ) young people appear over-represented in youth justice systems. This article argues that the exclusion of this group from human rights frameworks has an important flow-on effect: the marginalisation of the right of LGBTIQ young people to non-discrimination in policy and discourse that is informed by international human rights frameworks. After outlining the relevant frameworks, this article examines the evidence about LGBTIQ young people’s interactions with youth justice agencies, particularly police. The evidence indicates that the human rights of LGBTIQ young people are frequently breached in these interactions. We conclude by arguing that it is timely to consider how best to protect the human rights of LBGTIQ young people and keep their rights on the agenda.

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This research project investigated and designed a modular architecture for a 3D Reconfigurable Autopilot Flight System that could be used to control actuators in both manned and unmanned aircraft. The system is based on a CAN Bus interface and allows seamless control of different types of actuators. During the course of the research the differences and similarities of autopilots for fixed-wing general aviation aircraft and unmanned aircraft were analysed focusing on the actuator interfaces. This project suggests that software and hardware used in commercial-of-the-shelf avionics could be used in manned and unmanned aviation.

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This thesis explored the state of the use of e-learning tools within Learning Management Systems in higher education and developed a distinct framework to explain the factors influencing users' engagement with these tools. The study revealed that the Learning Management System design, preferences for other tools, availability of time, lack of adequate knowledge about tools, pedagogical practices, and social influences affect the uptake of Learning Management System tools. Semi structured interviews with 74 students and lecturers of a major Australian university were used as a source of data. The applied thematic analysis method was used to analyse the collected data.