430 resultados para systems safety
Resumo:
Cooperative collision warning system for road vehicles, enabled by recent advances in positioning systems and wireless communication technologies, can potentially reduce traffic accident significantly. To improve the system, we propose a graph model to represent interactions between multiple road vehicles in a specific region and at a specific time. Given a list of vehicles in vicinity, we can generate the interaction graph using several rules that consider vehicle's properties such as position, speed, heading, etc. Safety applications can use the model to improve emergency warning accuracy and optimize wireless channel usage. The model allows us to develop some congestion control strategies for an efficient multi-hop broadcast protocol.
Resumo:
Ecological dynamics characterizes adaptive behavior as an emergent, self-organizing property of interpersonal interactions in complex social systems. The authors conceptualize and investigate constraints on dynamics of decisions and actions in the multiagent system of team sports. They studied coadaptive interpersonal dynamics in rugby union to model potential control parameter and collective variable relations in attacker–defender dyads. A videogrammetry analysis revealed how some agents generated fluctuations by adapting displacement velocity to create phase transitions and destabilize dyadic subsystems near the try line. Agent interpersonal dynamics exhibited characteristics of chaotic attractors and informational constraints of rugby union boxed dyadic systems into a low dimensional attractor. Data suggests that decisions and actions of agents in sports teams may be characterized as emergent, self-organizing properties, governed by laws of dynamical systems at the ecological scale. Further research needs to generalize this conceptual model of adaptive behavior in performance to other multiagent populations.
Resumo:
The identification of attractors is one of the key tasks in studies of neurobiological coordination from a dynamical systems perspective, with a considerable body of literature resulting from this task. However, with regards to typical movement models investigated, the overwhelming majority of actions studied previously belong to the class of continuous, rhythmical movements. In contrast, very few studies have investigated coordination of discrete movements, particularly multi-articular discrete movements. In the present study, we investigated phase transition behavior in a basketball throwing task where participants were instructed to shoot at the basket from different distances. Adopting the ubiquitous scaling paradigm, throwing distance was manipulated as a candidate control parameter. Using a cluster analysis approach, clear phase transitions between different movement patterns were observed in performance of only two of eight participants. The remaining participants used a single movement pattern and varied it according to throwing distance, thereby exhibiting hysteresis effects. Results suggested that, in movement models involving many biomechanical degrees of freedom in degenerate systems, greater movement variation across individuals is available for exploitation. This observation stands in contrast to movement variation typically observed in studies using more constrained bi-manual movement models. This degenerate system behavior provides new insights and poses fresh challenges to the dynamical systems theoretical approach, requiring further research beyond conventional movement models.
Resumo:
In the study of complex neurobiological movement systems, measurement indeterminacy has typically been overcome by imposing artificial modelling constraints to reduce the number of unknowns (e.g., reducing all muscle, bone and ligament forces crossing a joint to a single vector). However, this approach prevents human movement scientists from investigating more fully the role, functionality and ubiquity of coordinative structures or functional motor synergies. Advancements in measurement methods and analysis techniques are required if the contribution of individual component parts or degrees of freedom of these task-specific structural units is to be established, thereby effectively solving the indeterminacy problem by reducing the number of unknowns. A further benefit of establishing more of the unknowns is that human movement scientists will be able to gain greater insight into ubiquitous processes of physical self-organising that underpin the formation of coordinative structures and the confluence of organismic, environmental and task constraints that determine the exact morphology of these special-purpose devices.
Resumo:
This paper provides much needed consolidation of the available evidence in relation to the design and evaluation of road safety advertising messages. Drawing upon current knowledge, the paper identifies some key challenges for improving both the persuasiveness of messages and the methods utilised to assess their effectiveness. The paper identifies some key message-related and individual difference factors, such as response efficacy, emotion, gender and involvement, which theoretical and empirical evidence has shown to be key determinants of message persuasiveness. In relation to message evaluation, the paper focuses upon research relating to the direct, persuasive role of advertising as opposed to evaluations of the combined effects of advertising and enforcement. The paper reviews methodological limitations of previous studies and gaps in existing knowledge that together limit the ability to draw accurate and comprehensive conclusions regarding message effectiveness. Overall, this paper provides a significant and timely review of what is currently known about road safety advertising design and evaluation.
Resumo:
Building integrated living systems (BILS), such as green roofs and living walls, could mitigate many of the challenges presented by climate change and biodiversity protection. However, few if any such systems have been constructed, and current tools for evaluating them are limited, especially under Australian subtropical conditions. BILS are difficult to assess, because living systems interact with complex, changing and site-specific social and environmental conditions. Our past research in design for eco-services has confirmed the need for better means of assessing the ecological values of BILS - let alone better models for assessing their thermal and hydrological performance. To address this problem, a research project is being developed jointly by researchers at the Central Queensland University (CQ University) and the Queensland University of Technology (QUT), along with industry collaborators. A mathematical model under development at CQ University will be applied and tested to determine its potential for predicting their complex, dynamic behaviour in different contexts. However, the paper focuses on the work at QUT. The QUT school of design is generating designs for living walls and roofs that provide a range of ecosystem goods and services, or ‘eco-services’, for a variety of micro-climates and functional contexts. The research at QUT aims to develop appropriate designs, virtual prototypes and quantitative methods for assessing the potential multiple benefits of BILS in subtropical climates. It is anticipated that the CQ University model for predicting thermal behaviour of living systems will provide a platform for the integration of ecological criteria and indicators. QUT will also explore means to predict and measure the value of eco-services provided by the systems, which is still largely uncharted territory. This research is ultimately intended to facilitate the eco-retrofitting of cities to increase natural capital and urban resource security - an essential component of sustainability. The talk will present the latest range of multifunctional, eco-productive living walls, roofs and urban space frames and their eco-services.
Resumo:
Despite ongoing enhancements to graduated licensing systems, young drivers continue to have a high risk of being killed or injured in car crashes. This study investigated the influence of parents and peers on the risky behaviour of young drivers, utilising Akers’ social learning theory. The specific factors examined related to parent and peer norms perceived by the young driver, and the rewards and punishments anticipated by the young driver from their parents and peers. A questionnaire was completed by 165 young drivers. Regression analysis revealed that these factors explained 54% of the variance in risky driving. The strongest predictor was anticipated parent rewards, followed by peer norms, and anticipated peer rewards. Exploratory analyses however revealed the profile of predictors varied for male and female participants, and for self-reported offenders and non-offenders. The results highlight the role of psychosocial factors in the risky behaviour of young drivers and the need for road safety policies and programs to consider the influence of both parents and peers upon this behaviour.
Resumo:
Risk-taking behaviour by motorcyclists has been shown to contribute to a substantial proportion of road crashes in Australia and abroad. Concern has been expressed that traditional motorcycle licence training programs do not sufficiently address such behaviour. Accordingly, the Three Steps to Safer Riding program was developed to address risk taking behaviour by riders as an adjunct to existing skills-based rider training. The program was designed to be delivered in a one hour classroom session at the start of training, with a 20 minute debrief to revise the key concepts at the end of training. This paper reports on the key training concepts, methodology and implementation of the pilot program with a major rider training organisation in Queensland and presents findings from a process evaluation. The Three Steps to Safer Riding intervention pilot was delivered to 518 learner riders over a three month period. Follow-up focus groups and one interview with intervention participants (N=18) five to eight months after completion of the program suggest that new riders (absolute novices) embraced and internalised many of the intervention concepts. However, some riders who had previous riding experience prior to training stated these issues were common sense, yet still expressed riding styles that were contrary to some of the key intervention messages. This is discussed in terms of raising awareness of risk issues for motorcyclists versus behaviour change. Additionally, interviews conducted with riding instructors are discussed regarding logistical challenges of implementation, training consistency, skills required to deliver the program, support for the program, and student engagement.
Resumo:
An emergent form of political economy, facilitated by information and communication technologies (ICTs), is widely propagated as the apotheosis of unmitigated social, economic, and technological progress. Meanwhile, throughout the world, social degradation and economic inequality are increasing logarithmically. Valued categories of thought are, axiomatically, the basic commodities of the “knowledge economy”. Language is its means of exchange. This paper proposes a sociolinguistic method with which to critically engage the hyperbole of the “Information Age”. The method is grounded in a systemic social theory that synthesises aspects of autopoiesis and Marxist political economy. A trade policy statement is analysed to exemplify the sociolinguistically created aberrations that are today most often construed as social and political determinants.
Resumo:
In this chapter I propose a theoretical framework for understanding the role of mediation processes in the inculcation, maintenance, and change of evaluative meaning systems, or axiologies, and how such a perspective can provide a useful and complementary dimension to analysis for SFL and CDA. I argue that an understanding of mediation—the movement of meaning across time and space—is essential for the analysis of meaning. Using two related texts as examples, I show how an understanding of mediation can aid SFL and CDA practitioners in the analysis of social change.
Resumo:
Context The School of Information Technology at QUT has recently undertaken a major restructuring of their Bachelor of Information Technology (BIT) course. Some of the aims of this restructuring include a reduction in first year attrition and to provide an attractive degree course that meets both student and industry expectations. Emphasis has been placed on the first semester in the context of retaining students by introducing a set of four units that complement one another and provide introductory material on technology, programming and related skills, and generic skills that will aid the students throughout their undergraduate course and in their careers. This discussion relates to one of these four fist semester units, namely Building IT Systems. The aim of this unit is to create small Information Technology (IT) systems that use programming or scripting, databases as either standalone applications or web applications. In the prior history of teaching introductory computer programming at QUT, programming has been taught as a stand alone subject and integration of computer applications with other systems such as databases and networks was not undertaken until students had been given a thorough grounding in those topics as well. Feedback has indicated that students do not believe that working with a database requires programming skills. In fact, the teaching of the building blocks of computer applications have been compartmentalized and taught in isolation from each other. The teaching of introductory computer programming has been an industry requirement of IT degree courses as many jobs require at least some knowledge of the topic. Yet, computer programming is not a skill that all students have equal capabilities of learning (Bruce et al., 2004) and this is clearly shown by the volume of publications dedicated to this topic in the literature over a broad period of time (Eckerdal & Berglund, 2005; Mayer, 1981; Winslow, 1996). The teaching of this introductory material has been done pretty much the same way over the past thirty years. During this period of time that introductory computer programming courses have been taught at QUT, a number of different programming languages and programming paradigms have been used and different approaches to teaching and learning have been attempted in an effort to find the golden thread that would allow students to learn this complex topic. Unfortunately, computer programming is not a skill that can be learnt in one semester. Some basics can be learnt but it can take many years to master (Norvig, 2001). Faculty data typically has shown a bimodal distribution of results for students undertaking introductory programming courses with a high proportion of students receiving a high mark and a high proportion of students receiving a low or failing mark. This indicates that there are students who understand and excel with the introductory material while there is another group who struggle to understand the concepts and practices required to be able to translate a specification or problem statement into a computer program that achieves what is being requested. The consequence of a large group of students failing the introductory programming course has been a high level of attrition amongst first year students. This attrition level does not provide good continuity in student numbers in later years of the degree program and the current approach is not seen as sustainable.
Resumo:
Young drivers aged 17-24 are consistently overrepresented in motor vehicle crashes. Research has shown that a young driver’s crash risk increases when carrying similarly aged passengers, with fatal crash risk increasing two to three fold with two or more passengers. Recent growth in access to and use of the internet has led to a corresponding increase in the number of web based behaviour change interventions. An increasing body of literature describes the evaluation of web based programs targeting risk behaviours and health issues. Evaluations have shown promise for such strategies with evidence for positive changes in knowledge, attitudes and behaviour. The growing popularity of web based programs is due in part to their wide accessibility, ability for personalised tailoring of intervention messages, and self-direction and pacing of online content. Young people are also highly receptive to the internet and the interactive elements of online programs are particularly attractive. The current study was designed to assess the feasibility for a web based intervention to increase the use of personal and peer protective strategies among young adult passengers. An extensive review was conducted on the development and evaluation of web based programs. Year 12 students were also surveyed about their use of the internet in general and for health and road safety information. All students reported internet access at home or at school, and 74% had searched for road safety information. Additional findings have shown promise for the development of a web based passenger safety program for young adults. Design and methodological issues will be discussed.
Resumo:
Research has shown that road lane width impacts on driver behaviour. This literature review provides guidelines to assist in the design, construction and retrofitting of urban roads to accommodate road users' safety requirements. It focuses on the impacts of lane widths on cyclists and motor vehicle safety behaviour. The literature review commenced with a search of library databases. Peer reviewed articles and road authority (local, state and national) reports were reviewed. The majority of studies investigating the effects of lane width on driver behaviour were simulator based, while research into cycling safety involved data collected from actual traffic environments. Results show that marked road lane width influences perceived task difficulty, risk perception and possibly speed choice. The positioning of cyclists in traffic lanes is influenced by the presence of on-road cycling facilities and the total roadway width. The lateral displacement between bicycle and vehicle is smallest when a bicycle facility is present. Lower, or reduced, vehicle speeds play a significant role in improving bicyclist and pedestrian safety. It is also shown that if road lane widths in urban areas were reduced, to a functional width that was less than the current guidelines of 3.5m, it could result in a safer road environment for all road users.
Resumo:
Street racing and associated (hooning) behaviours have attracted increasing concern in recent years. While New Zealand and all Australian jurisdictions have introduced “antihooning” legislation and allocated significant police resources to managing the problem, there is limited evidence of the road safety implications of hooning. However, international and Australian data suggests that drivers charged with a hooning offence tend to be young males who are accompanied by one or more peers, and hooning-related crashes tend to occur at night. In this regard, there is considerable evidence that drivers under the age of 25 are over-represented in crash statistics, and are particularly vulnerable soon after obtaining a Provisional licence, when driving at night, and when carrying peer-aged passengers. The similarity between the nature of hooning offenders, offences and crashes, and road safety risks for young drivers in general, suggests that hooning is an issue that may be viewed as part of the broader young driver problem. Many jurisdictions have recently implemented a range of evidence-based strategies to address young driver road safety, and this paper will present Queensland crash and offence data to highlight the potential benefit of Graduated Driver Licensing initiatives, such as night driving restrictions and peer-aged passenger restrictions, to related road safety issues, including hooning. An understanding of potential flow-on effects is important for evaluations of anti-hooning legislation and Graduated Driver Licensing programs, and may have implications for future law enforcement resource allocation and policy development.
Resumo:
We propose an efficient and low-complexity scheme for estimating and compensating clipping noise in OFDMA systems. Conventional clipping noise estimation schemes, which need all demodulated data symbols, may become infeasible in OFDMA systems where a specific user may only know his own modulation scheme. The proposed scheme first uses equalized output to identify a limited number of candidate clips, and then exploits the information on known subcarriers to reconstruct clipped signal. Simulation results show that the proposed scheme can significantly improve the system performance.