825 resultados para Urban streets networks
Resumo:
This paper characterises nitrogen and phosphorus wash-off processes on urban road surfaces to create fundamental knowledge to strengthen stormwater treatment design. The study outcomes confirmed that the composition of initially available nutrients in terms of their physical association with solids and chemical speciation determines the wash-off characteristics. Nitrogen and phosphorus wash-off processes are independent of land use, but there are notable differences. Nitrogen wash-off is a “source limiting” process while phosphorus wash-off is “transport limiting”. Additionally, a clear separation between nitrogen and phosphorus wash-off processes based on dissolved and particulate forms confirmed that the common approach of replicating nutrients wash-off based on solids wash-off could lead to misleading outcomes particularly in the case of nitrogen. Nitrogen is present primarily in dissolved and organic form and readily removed even by low intensity rainfall events, which is an important consideration for nitrogen removal targeted treatment design. In the case of phosphorus, phosphate constitutes the primary species in wash-off for the particle size fraction <75 µm, while other species are predominant in particle size range >75 µm. This means that phosphorus removal targeted treatment design should consider both phosphorus speciation as well as particle size.
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The existence of the Macroscopic Fundamental Diagram (MFD), which relates network space-mean density and flow, has been shown in urban networks under homogeneous traffic conditions. Since the MFD represents the area-wide network traffic performances, studies on perimeter control strategies and an area traffic state estimation utilizing the MFD concept has been reported. The key requirements for the well-defined MFD is the homogeneity of the area wide traffic condition, which is not universally expected in real world. For the practical application of the MFD concept, several researchers have identified the influencing factors for network homogeneity. However, they did not explicitly take drivers’ behaviour under real time information provision into account, which has a significant impact on the shape of the MFD. This research aims to demonstrate the impact of drivers’ route choice behaviour on network performance by employing the MFD as a measurement. A microscopic simulation is chosen as an experimental platform. By changing the ratio of en-route informed drivers and pre-trip informed drivers as well as by taking different route choice parameters, various scenarios are simulated in order to investigate how drivers’ adaptation to the traffic congestion influences the network performance and the MFD shape. This study confirmed and addressed the impact of information provision on the MFD shape and highlighted the significance of the route choice parameter setting as an influencing factor in the MFD analysis.
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The ageing population is increasing worldwide, as are a range of chronic diseases, conditions, and physical and cognitive disabilities associated with later life. The older population is also neurologically diverse, with unique and specific challenges around mobility and engagement with the urban environment. Older people tend to interact less with cities and neighbourhoods, putting them at risk of further illnesses and co-morbidities associated with being less physically and socially active. Empirical evidence has shown that reduced access to healthcare services, health-related resources and social interaction opportunities is associated with increases in morbidity and premature mortality. While it is crucial to respond to the needs of this ageing population, there is insufficient evidence for interventions regarding their experiences of public space from the vantage point of neurodiversity. This paper provides a conceptual and methodological framework to investigate relationships between the sensory and cognitive abilities of older people, and their use and negotiation of the urban environment. The paper will refer to a case example of the city of Logan, an urban area in Queensland, Australia, where current urban development provides opportunities for the design of spaces that take experiences of neurodiversity into account. The framework will inform the development of principles for urban design for increasingly neurologically diverse populations.
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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 verifying the applicability of those WSNs with respect to demanding SHM applications like modal analysis and damage identification. This paper first presents a brief review of the most inherent uncertainties of the SHM-oriented WSN platforms and then investigates their effects on outcomes and performance of the most robust Output-only Modal Analysis (OMA) techniques when employing merged data from multiple tests. The two OMA families selected for this investigation are Frequency Domain Decomposition (FDD) and Data-driven Stochastic Subspace Identification (SSI-data) due to the fact that they both have been widely applied in the past decade. Experimental accelerations collected by a wired sensory system on a large-scale laboratory bridge model are initially used as clean data before being contaminated by different data pollutants in sequential manner to simulate practical SHM-oriented WSN uncertainties. The results of this study show the robustness of FDD and the precautions needed for SSI-data family when dealing with SHM-WSN uncertainties. Finally, the use of the measurement channel projection for the time-domain OMA techniques and the preferred combination of the OMA techniques to cope with the SHM-WSN uncertainties is recommended.
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Vietnam is currently undergoing a metamorphosis from a relatively closed society with a centrally planned economy, to a rapidly urbanising one with a global outlook. These changes have been the catalyst for an exciting ferment of activity in popular culture. This volume contains contributions from scholars engaged in the most up-to-date social research in Vietnam, as well as some of Vietnam's most popular cultural producers who are forging new ways of imagining the present whilst at the same time engaging actively in reinterpreting the past. The diverse ways that Vietnam is culturally and socially negotiating the future are examined as the book addresses issues of indigenisation of cultural influences, ambivalence surrounding change, and the consistent blurring of boundaries between informal, non-state cultural activities and formal institutional structures in the evolution of a civil society in Vietnam.
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In urban locations in Australia and elsewhere, public space may be said to be under attack from developers and also from attempts by civic authorities to oversee and control it (Davis 1995, Mitchell 2003, Watson 2006, Iveson 2006). The use of public space use by young people in particular, raises issues in Australia and elsewhere in the world. In a context of monitoring and control procedures, young people’s use of public space is often viewed as a threat to the prevailing social order (Loader 1996, White 1998, Crane and Dee 2001). This paper discusses recent technological developments in the surveillance, governance and control of public space used by young people, children and people of all ages.
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Informal learning networks play a key role in the skill and professional development of professionals working in micro-businesses within Australia’s digital content industry as they do not necessarily have access to a learning and development or a human resources section that can assist in mapping their learning pathway. Professionals working in this environment would typically adopt an informal learning approach to their skill and professional development by utilising their social and business networks. The overall aim of this PhD research project is to study how these professionals manage their skill and professional development, and to explore what role informal learning networks play in this professional learning context. This paper will describe the theme of the research project and how it fits with previous research and other relevant studies. Secondly, it will present the study’s research focus, and the research questions. It will also present relevant theories and perspectives, and the methods for empirical data collection. Data collection will be through three distinct phases using a mixed methods research design: an online survey, interviews, and case studies. It should be noted the findings presented in this paper offer some early results of the research project.
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Next generation screens of diverse dimensions such as the Pebble e-paper watch, Google’s Project Glass, Microsoft’s Kinect and IllumiRoom, and large-scale multi-touch screen surface areas, increasingly saturate and diversify the urban mediascape. This paper seeks to contribute to media architecture and interaction design theory by starting to critically examine how these different screen formats are creating a ubiquitous screen mediascape across the city. We introduce next generation personal, domestic, and public screens. The paper critically challenges conventional dichotomies such as local / global, online / offline, private / public, large / small, mobile / static, that have been created in the past to describe some of the qualities and characteristics of interfaces and their usage. More and more scholars recognise that the black and white nature of these dichotomies does not adequately represent the fluid and agile capabilities of many new screen interfaces. With this paper, we hope to illustrate the more nuanced ‘trans-scalar’ qualities of these new urban interactions, that is, ways in which they provide a range functionality, without being locked into either end of a scale.
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A technologically innovative study was undertaken across two suburbs in Brisbane, Australia, to assess socioeconomic differences in women's use of the local environment for work, recreation, and physical activity. Mothers from high and low socioeconomic suburbs were instructed to continue with usual daily routines, and to use mobile phone applications (Facebook Places, Twitter, and Foursquare) on their mobile phones to ‘check-in’ at each location and destination they reached during a one-week period. These smartphone applications are able to track travel logistics via built-in geographical information systems (GIS), which record participants’ points of latitude and longitude at each destination they reach. Location data were downloaded to Google Earth and excel for analysis. Women provided additional qualitative data via text regarding the reasons and social contexts of their travel. We analysed 2183 ‘check-ins’ for 54 women in this pilot study to gain quantitative, qualitative, and spatial data on human-environment interactions. Data was gathered on distances travelled, mode of transport, reason for travel, social context of travel, and categorised in terms of physical activity type – walking, running, sports, gym, cycling, or playing in the park. We found that the women in both suburbs had similar daily routines with the exception of physical activity. We identified 15% of ‘check-ins’ in the lower socioeconomic group as qualifying for the physical activity category, compared with 23% in the higher socioeconomic group. This was explained by more daily walking for transport (1.7kms to 0.2kms) and less car travel each week (28.km to 48.4kms) in the higher socioeconomic suburb. We ascertained insights regarding the socio-cultural influences on these differences via additional qualitative data. We discuss the benefits and limitations of using new technologies and Google Earth with implications for informing future physical and social aspects of urban design, and health promotion in socioeconomically diverse cities.
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IEEE 802.11 based wireless local area networks (WLANs) are being increasingly deployed for soft real-time control applications. However, they do not provide quality-ofservice (QoS) differentiation to meet the requirements of periodic real-time traffic flows, a unique feature of real-time control systems. This problem becomes evident particularly when the network is under congested conditions. Addressing this problem, a media access control (MAC) scheme, QoS-dif, is proposed in this paper to enable QoS differentiation in IEEE 802.11 networks for different types of periodic real-time traffic flows. It extends the IEEE 802.11e Enhanced Distributed Channel Access (EDCA) by introducing a QoS differentiation method to deal with different types of periodic traffic that have different QoS requirements for real-time control applications. The effectiveness of the proposed QoS-dif scheme is demonstrated through comparisons with the IEEE 802.11e EDCA mechanism.
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This book develops tools and techniques that will help urban residents gain access to urban computing. Metaphorically speaking, it is taking computing to the street by giving the general public – rather than just researchers and professionals – the power to leverage available city infrastructure and create solutions tailored to their individual needs. It brings together five chapters that are based on presentations given at the Street Computing Workshop held on 24 November 2009 in Melbourne in conjunction with the Australian Computer-Human Interaction Conference (OZCHI 2009). This book focuses on applying urban informatics, urban and community sensing and open application programming interfaces (APIs) to the public space through the delivery of online services, on demand and in real time. It then offers a case study of how the city of Singapore has harnessed the potential of an online infrastructure so that residents and visitors can access services electronically. This book was published as a special issue of the Journal of Urban Technology, 19(2), 2012.
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The emergence of global computer networks and the ubiquitous availability of advanced information and communication technology (ICT) since the mid Nineties has given rise to the hope that the traditional disadvantages faced by regional economies and regional communities could be elevated easily and swiftly. Yet, the experience of both community informatics and community development researchers and practitioners tells a different tale. Although the potential of ICT is in fact realised in some situations and locations and does provide means to ensure sustainability in some regional communities, elsewhere it has not been taken up or has not been able to elicit change for the promised better. Too many communities are still faced by a centralised structure in the context of commerce, service provision or governance and by various degrees of digital divides between connected and disconnected, between media literate and illiterate, between young and old, and between urban and rural. Many attempts to close or bridge the digital divide have been reported with various degrees of success (cf. Menou, 2001; Servon, 2002). Most of these accounts echo a common voice in that they report similar principles of action, and they reflect – in most cases unconsciously – practices of sociocultural animation. This article seeks to shed light onto the concept of sociocultural animation which is already commonplace in various forms in the arts, in education and professional development, youth work, sports, town planning, careers services, entrepreneurship and tourism. It starts by exploring the origins of sociocultural animation and draws parallels to the current state of research and practice. It unpacks the foundation of sociocultural animation and briefly describes underlying principles and how they can be applied in the context of community informatics and developing regional communities with ICT. Finally, further areas of investigation are being proposed.
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Modelling how a word is activated in human memory is an important requirement for determining the probability of recall of a word in an extra-list cueing experiment. Previous research assumed a quantum-like model in which the semantic network was modelled as entangled qubits, however the level of activation was clearly being over-estimated. This paper explores three variations of this model, each of which are distinguished by a scaling factor designed to compensate the overestimation.
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We consider the problem of maximizing the secure connectivity in wireless ad hoc networks, and analyze complexity of the post-deployment key establishment process constrained by physical layer properties such as connectivity, energy consumption and interference. Two approaches, based on graph augmentation problems with nonlinear edge costs, are formulated. The first one is based on establishing a secret key using only the links that are already secured by shared keys. This problem is in NP-hard and does not accept polynomial time approximation scheme PTAS since minimum cutsets to be augmented do not admit constant costs. The second one extends the first problem by increasing the power level between a pair of nodes that has a secret key to enable them physically connect. This problem can be formulated as the optimal key establishment problem with interference constraints with bi-objectives: (i) maximizing the concurrent key establishment flow, (ii) minimizing the cost. We prove that both problems are NP-hard and MAX-SNP with a reduction to MAX3SAT problem.