364 resultados para collision avoidance
Resumo:
Purpose We designed a visual field test focused on the field utilized while driving to examine associations between field impairment and motor vehicle collision involvement in 2,000 drivers ≥70 years old. Methods The "driving visual field test" involved measuring light sensitivity for 20 targets in each eye, extending 15° superiorly, 30° inferiorly, 60° temporally and 30° nasally. The target locations were selected on the basis that they fell within the field region utilized when viewing through the windshield of a vehicle or viewing the dashboard while driving. Monocular fields were combined into a binocular field based on the more sensitive point from each eye. Severe impairment in the overall field or a region was defined as average sensitivity in the lowest quartile of sensitivity. At-fault collision involvement for five years prior to enrollment was obtained from state records. Poisson regression was used to calculate crude and adjusted rate ratios examining the association between field impairment and at-fault collision involvement. Results Drivers with severe binocular field impairment in the overall driving visual field had a 40% increased rate of at-fault collision involvement (RR 1.40, 95%CI 1.07-1.83). Impairment in the lower and left fields was associated with elevated collision rates (RR 1.40 95%CI 1.07-1.82 and RR 1.49, 95%CI 1.15-1.92, respectively), whereas impairment in the upper and right field regions was not. Conclusions Results suggest that older drivers with severe impairment in the lower or left region of the driving visual field are more likely to have a history of at-fault collision involvement.
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This thesis examines perceptions of advertising on social networking sites (SNS), in particular consumers' privacy concerns, advertising engagement and advertising avoidance. It contributes to the understanding of social media by providing results of a longitudinal investigation of consumer perceptions of advertising, a topography of engagement and avoidance triggers and a three dimensional model of advertising avoidance on SNS. This research used a mixed methodology, employing Critical Incident Technique, In-depth interviews and online surveys.
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In this paper we present concrete collision and preimage attacks on a large class of compression function constructions making two calls to the underlying ideal primitives. The complexity of the collision attack is above the theoretical lower bound for constructions of this type, but below the birthday complexity; the complexity of the preimage attack, however, is equal to the theoretical lower bound. We also present undesirable properties of some of Stam’s compression functions proposed at CRYPTO ’08. We show that when one of the n-bit to n-bit components of the proposed 2n-bit to n-bit compression function is replaced by a fixed-key cipher in the Davies-Meyer mode, the complexity of finding a preimage would be 2 n/3. We also show that the complexity of finding a collision in a variant of the 3n-bits to 2n-bits scheme with its output truncated to 3n/2 bits is 2 n/2. The complexity of our preimage attack on this hash function is about 2 n . Finally, we present a collision attack on a variant of the proposed m + s-bit to s-bit scheme, truncated to s − 1 bits, with a complexity of O(1). However, none of our results compromise Stam’s security claims.
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There is a need for systems which can autonomously perform coverage tasks on large outdoor areas. Unfortunately, the state-of-the-art is to use GPS based localization, which is not suitable for precise operations near trees and other obstructions. In this paper we present a robotic platform for autonomous coverage tasks. The system architecture integrates laser based localization and mapping using the Atlas Framework with Rapidly-Exploring Random Trees path planning and Virtual Force Field obstacle avoidance. We demonstrate the performance of the system in simulation as well as with real world experiments.
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Despite the extent of works done on modelling port water collisions, not much research effort has been devoted to modelling collisions at port anchorages. This paper aims to fill this important gap in literature by applying the Navigation Traffic Conflict Technique (NTCT) for measuring the collision potentials in anchorages and for examining the factors contributing to collisions. Grounding on the principles of the NTCT, a collision potential measurement model and a collision potential prediction model were developed. These models were illustrated by using vessel movement data of the anchorages in Singapore port waters. Results showed that the measured collision potentials are in close agreement with those perceived by harbour pilots. Higher collision potentials were found in anchorages attached to shoreline and international fairways, but not at those attached to confined water. Higher operating speeds, larger numbers of isolated danger marks and day conditions were associated with reduction in the collision potentials.
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We address the problem of the rangefinder-based avoidance of unforeseen static obstacles during a visual navigation task. We extend previous strategies which are efficient in most cases but remain still hampered by some drawbacks (e.g., risks of collisions or of local minima in some particular cases, etc.). The key idea is to complete the control strategy by adding a controller providing the robot some anticipative skills to guarantee non collision and by defining more general transition conditions to deal with local minima. Simulation results show the proposed strategy efficiency.
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Objective To examine the association between glaucoma and motor vehicle collision (MVC) involvement among older drivers, including the role of visual field impairment that may underlie any association found. Design A retrospective population-based study Participants A sample of 2,000 licensed drivers aged 70 years and older who reside in north central Alabama. Methods At-fault MVC involvement for five years prior to enrollment was obtained from state records. Three aspects of visual function were measured: habitual binocular distance visual acuity, binocular contrast sensitivity and the binocular driving visual field constructed from combining the monocular visual fields of each eye. Poisson regression was used to calculate crude and adjusted rate ratios (RR) and 95% confidence intervals (CI). Main Outcomes Measures At-fault MVC involvement for five years prior to enrollment. Results Drivers with glaucoma (n = 206) had a 1.65 (95% confidence interval [CI] 1.20-2.28, p = 0.002) times higher MVC rate compared to those without glaucoma after adjusting for age, gender and mental status. Among those with glaucoma, drivers with severe visual field loss had higher MVC rates (RR = 2.11, 95% CI 1.09-4.09, p = 0.027), whereas no significant association was found among those with impaired visual acuity and contrast sensitivity. When the visual field was sub-divided into six regions (upper, lower, left, and right visual fields; horizontal and vertical meridians), we found that impairment in the left, upper or lower visual field was associated with higher MVC rates, and an impaired left visual field showed the highest RR (RR = 3.16, p = 0.001) compared to other regions. However, no significant association was found in deficits in the right side or along the horizontal or vertical meridian. Conclusions A population-based study suggests that older drivers with glaucoma are more likely to have a history of at-fault MVC involvement than those without glaucoma. Impairment in the driving visual field in drivers with glaucoma appears to have an independent association with at-fault MVC involvement, whereas visual acuity and contrast sensitivity impairments do not.
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The report of the Senate Economics References Committee inquiry into corporate tax avoidance comes with the subtitle – “You cannot tax what you cannot see”, with a strong focus on increased transparency. The majority of the 17 recommendations in the interim report relate to improved transparency of the tax affairs of corporate taxpayers. This is a significant step in the right direction. Recent experiences in the war on corporate tax avoidance both in Australia and overseas confirm that “information is power”. Most notably, we have seen increased transparency changing the behaviour of multinational enterprises as well as inducing governments to act.
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The Turnbull Government announced yet another measure aimed at addressing tax base erosion and profit shifting, placing additional requirements on new foreign investment under the existing national interest test. In the last 12 months Australia has seen various reforms within the tax system. However, this latest initiative is a shift as it links Australia’s tax regime with its foreign investment regime. It sends a broader signal to the market that Australia will look beyond the collection of tax revenues to a consideration of national interest.
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Previous research has shown that action tendencies to approach alcohol may be modified using computerized ApproacheAvoidance Task (AAT), and that this impacted on subsequent consumption. A recent paper in this journal (Becker, Jostman, Wiers, & Holland, 2015) failed to show significant training effects for food in three studies: Nor did it find effects on subsequent consumption. However, avoidance training to high calorie foods was tested against a control rather than Approach training. The present study used a more comparable paradigm to the alcohol studies. It randomly assigned 90 participants to ‘approach’ or ‘avoid’ chocolate images on the AAT, and then asked them to taste and rate chocolates. A significant interaction of condition and time showed that training to avoid chocolate resulted in faster avoidance responses to chocolate images, compared with training to approach it. Consistent with Becker et al.'s Study 3, no effect was found on amounts of chocolate consumed, although a newly published study in this journal (Schumacher, Kemps, & Tiggemann, 2016) did do so. The collective evidence does not as yet provide solid basis for the application of AAT training to reduction of problematic food consumption, although clinical trials have yet to be conducted.
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We have already seen major amendments to Australia’s tax regime to tackle base erosion and profit shifting (BEPS). Several more significant measures were announced in the federal budget, most notably the diverted profits tax, aimed at multinationals which shift tax to a lower taxing jurisdiction. Yet to date, a very simple tax minimisation strategy has been largely ignored in the ongoing reforms and was ignored in the federal budget. Excessive debt loading is a problem that not been afforded the same attention as other aggressive tax planning strategies adopted by multinationals.
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This document outlines a framework that could be used by government agencies in assessing policy interventions aimed at achieving social outcomes from government construction contracts. The framework represents a rational interpretation of the information gathered during the multi-outcomes construction policies project. The multi-outcomes project focused on the costs and benefits of using public construction contracts to promote the achievement of training and employment and public art objectives. The origin of the policy framework in a cost-benefit appraisal of current policy interventions is evidenced by its emphasis on sensitivity to policy commitment and project circumstances (especially project size and scope).The quantitative and qualitative analysis conducted in the multi-outcomes project highlighted, first, that in the absence of strong industry commitment to policy objectives, policy interventions typically result in high levels of avoidance activity, substantial administrative costs and very few benefits. Thus, for policy action on, for example, training or local employment to be successful compliance issues must be adequately addressed. Currently it appears that pre-qualification schemes (similar to the Priority Access Scheme) and schemes that rely on measuring, for example, the training investments of contractors within particular projects do not achieve high levels of compliance and involve significant administrative costs. Thus, an alternative is suggested in the policy framework developed here: a levy on each public construction project – set as a proportion of the total project costs. Although a full evaluation of this policy alternative was beyond the scope of the multi-outcomes construction policies project, it appears to offer the potential to minimize the transaction costs on contractors whilst enabling the creation of a training agency dedicated to improving the supply of skilled construction labour. A recommendation is thus made that this policy alternative be fully researched and evaluated. As noted above, the outcomes of the multi-outcomes research project also highlighted the need for sensitivity to project circumstances in the development and implementation of polices for public construction projects. Ideally a policy framework would have the flexibility to respond to circumstances where contractors share a commitment to the policy objectives and are able to identify measurable social outcomes from the particular government projects they are involved in. This would involve a project-by-project negotiation of goals and performance measures. It is likely to only be practical for large, longer term projects.
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This study explores teenager perceptions towards advertising in the online social networking environment. The future of online social networking sites is dependant upon the continued support of advertisers in this new medium, which is linked to the acceptance of advertising on these sites by their targeted audience. This exploratory study used the qualitative research methods of focus groups and in-depth personal interviews to gain insights from the teenager participants. The literature review in Chapter Two examined the previous research into advertising theories, consumer attitudes and issues such as advertising avoidance, advertising as a service and trust and privacy in the online social networking environment. The teenage consumer was also examined as were the influences of social identity theory. From this literature review eleven propositions were formed which provided a structure to the analysis of the research. Chapter Three outlined the multi-method research approach of using focus groups and in-depth interviews. The key findings were outlined in Chapter Four and Chapter Five provides discussion regarding these findings and the implications for theory and advertising practice. The main findings from this study suggest that teenagers have very high levels of advertising avoidance and are sceptical towards advertising on their online social networking sites. They have an inherent distrust of commercial messages in the online social networking environment; however they are extremely trusting with the information that they disclose online. They believe that if their site is classified as private, then the information disclosed on this site is not accessible to anyone. The study explores the reasons behind these views. This research has resulted in the identification of seven motivations behind online social networking use. A new model of advertising avoidance in the online social networking environment is also presented and discussed. This model makes a contribution towards filling the gap in available research on online social networking sites and advertising perception. The findings of this study have also resulted in the identification of the characteristics of online social networking sites as an advertising medium. The newness of online social networking sites coupled with the enthusiastic adoption of online social networking by the teenage demographic means that this exploratory study will be of interest to both academics and practitioners alike.
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The decision as to which procurement system to adopt is a complex and challenging task for clients of construction projects. Despite a plethora of tools and techniques available for selecting a procurement method, clients are still uncertain about what method to adopt for a given construction project to achieve success. This paper examines ‘how and why’ procurement methods are selected by public sector clients in Queensland (QLD) and Western Australia (WA). Findings from workshops with senior managers in procurement selection revealed that traditional lump sum methods (TLS) are preferred even though alternative forms could be better suited for a given project. Participants of the workshops agreed that alternative procurement forms should be considered for projects but an embedded culture of uncertainty avoidance meant the selection of TLS methods. It was perceived that only a limited number of contractors operating in the marketplace have the resources and experience to deliver projects using the non-traditional methods.
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This paper explores the likely efficacy of government agencies using their contracting relationships with private firms to affect training outcomes in the construction industry. Specifically, it reports on the results of a study of two training policies of theWestern Australian government. Empirical data is drawn from the government’s Tender Registration System between 1997 and 2006. The main finding of the quantitative analysis is that in the absence of strong industry commitment to policy objectives, the contracting approach is likely to result in high levels of avoidance activity and generate very few benefits. The results of a qualitative investigation also support these findings.