947 resultados para Endeavour (Ship)
Resumo:
The invention of asymmetric encryption back in the seventies was a conceptual leap that vastly increased the expressive power of encryption of the times. For the first time, it allowed the sender of a message to designate the intended recipient in an cryptographic way, expressed as a “public key” that was related to but distinct from the “private key” that, alone, embodied the ability to decrypt. This made large-scale encryption a practical and scalable endeavour, and more than anything else—save the internet itself—led to the advent of electronic commerce as we know and practice it today.
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Non-profit organizations (NPOs) are major providers of services in many fields of endeavour, and often receive financial support from government. This article investigates different forms of government/nonprofit funding relationships, with the viewpoint being mainly, though not exclusively, from the perspective of the non-profit agencies. While there are a number of existing typologies of government/NPO relations, these are dated and in need of further empirical analysis and testing. The article advances an empirically derived extension to current models of government/NPO relations. A future research agenda is outlined based on the constructs that underpin typologies, rather than discrete categorization of relationships.
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In this chapter, we present a case study of control system design for rudderbased stabilisers of ships using RHC. The rudder’s main function is to correct the heading of a ship; however, depending on the type of ship, the rudder may also be used to produce, or correct, roll motion. Rudder roll stabilisation consists of using rudder-induced roll motion to reduce the roll motion induced by waves. When this technique is employed, an automatic control system is necessary to provide the rudder command based on measurements of ship motion. The RHC formulation provides a unified framework to address many of the difficulties associated with this control system design problem.
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This paper presents two novel nonlinear models of u-shaped anti-roll tanks for ships, and their linearizations. In addition, a third simplified nonlinear model is presented. The models are derived using Lagrangian mechanics. This formulation not only simplifies the modeling process, but also allows one to obtain models that satisfy energy-related physical properties. The proposed nonlinear models and their linearizations are validated using model-scale experimental data. Unlike other models in the literature, the nonlinear models in this paper are valid for large roll amplitudes. Even at moderate roll angles, the nonlinear models have three orders of magnitude lower mean square error relative to experimental data than the linear models.
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In this article, we have described the main components of a ship motion-control system and two particular motion-control problems that require wave filtering, namely, dynamic positioning and heading autopilot. Then, we discussed the models commonly used for vessel response and showed how these models are used for Kalman filter design. We also briefly discussed parameter and noise covariance estimation, which are used for filter tuning. To illustrate the performance, a case study based on numerical simulations for a ship autopilot was considered. The material discussed in this article conforms to modern commercially available ship motion-control systems. Most of the vessels operating in the offshore industry worldwide use Kalman filters for velocity estimation and wave filtering. Thus, the article provides an up-to-date tutorial and overview of Kalman-filter-based wave filtering.
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In extreme weather conditions, thrusters on ships and rigs may be subject to severe thrust losses caused by ventilation and in-and-out-of-water events. When a thruster ventilates, air is sucked down from the surface and into the propeller. In more severe cases, parts of or even the whole propeller can be out of the water. These losses vary rapidly with time and cause increased wear and tear in addition to reduced thruster performance. In this paper, a thrust allocation strategy is proposed to reduce the effects of thrust losses and to reduce the possibility of multiple ventilation events. This thrust allocation strategy is named antispin thrust allocation, based on the analogous behavior of antispin wheel control of cars. The proposed thrust allocation strategy is important for improving the life span of the propulsion system and the accuracy of positioning for vessels conducting station keeping in terms of dynamic positioning or thruster-assisted position mooring. Application of this strategy can result in an increase of operational time and, thus, increased profitability. The performance of the proposed allocation strategy is demonstrated with experiments on a model ship.
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The motion of marine vessels has traditionally been studied using two different approaches: manoeuvring and seakeeping. These two approaches use different reference frames and coordinate systems to describe the motion. This paper derives the kinematic models that characterize the transformation of motion variables (position, velocity, accelerations) and forces between the different coordinate systems used in these theories. The derivations hereby presented are done in terms of the formalism adopted in robotics. The advantage of this formulation is the use of matrix notation and operations. As an application, the transformation of linear equations of motion used in seakeeping into body-fixed coordinates is considered for both zero and forward speed.
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The role of law in managing public health challenges such as influenza pandemics poses special challenges. This article reviews Australian plans in the context of the H1N1 09 experience to assess whether risk management was facilitated or inhibited by the "number" of levels or phases of management, the degree of prescriptive detail for particular phases, the number of plans, the clarity of the relationship between them, and the role of the media. Despite differences in the content and form of the plans at the time of the H1N1 09 emerging pandemic, the article argues that in practice, the plans proved to be responsive and robust bases for managing pandemic risks. It is suggested that this was because the plans proved to be frameworks for coordination rather than prescriptive straitjackets, to be only one component of the regulatory response, and to offer the varied tool box of possible responses, as called for by the theory of responsive regulation. Consistent with the principle of subsidiarity, it is argued that the plans did not inhibit localised responses such as selective school closures or rapid responses to selected populations such as cruise ship passengers.
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Uanda house is of historical importance to Queensland both in terms of its architectural design and its social history. Uanda is a low set, single story house built in 1928, located in the inner city Brisbane suburb of Wilston. Architecturally, the house has a number of features that distinguish it from the surrounding bungalow influenced inter-war houses. The house has been described as a Queensland style house with neo-Georgian influences. Historically, it is associated with the entry of women into the profession of architecture in Queensland. Uanda is the only remaining intact work of architect/draftswoman Nellie McCredie and one of a very few examples of works by pioneering women architects in Queensland. The house was entered into the Queensland Heritage Register, in 2000, after an appeal against Brisbane City Council’s refusal of an application to demolish the house was disputed in the Queensland Planning and Environment court in 1998/1999. In the court’s report, Judge Robin QC, DCJ, stated that, “The importance of preserving women's history and heritage, often previously marginalised or lost, is now accepted at government level, recognising that role models are vital for bringing new generations of women into the professions and public life.” While acknowledging women’s contribution to the profession of architecture is an important endeavour, it also has the potential to isolate women architects as separate to a mainstream history of architecture. As Julie Willis writes, it can imply an atypical, feminine style of architecture. What is the impact or potential implications of recognising heritage buildings designed by women architects? The Judge also highlights the absence of a recorded history of unique Brisbane houses and questions the authority of the heritage register. This research looks at these points of difference through a case study of the Uanda house. The paper will investigate the processes of adding the house to the heritage register, the court case and existing research on Nellie McCredie and Uanda House.
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Parametric ship roll resonance is a phenomenon where a ship can rapidly develop high roll motion while sailing in longitudinal waves. This effect can be described mathematically by periodic changes of the parameters of the equations of motion, which lead to a bifurcation. In this paper, the control design of an active u-tank stabilizer is carried out using Lyapunov theory. A nonlinear backstepping controller is developed to provide global exponential stability of roll. An extension of commonly used u-tank models is presented to account for large roll angles, and the control design is tested via simulation on a high-fidelity model of a vessel under parametric roll resonance.
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In 2005, governments around the world unanimously agreed to the principle of the responsibility to protect (R2P), which holds that all states have a responsibility to protect their populations from genocide and mass atrocities, that the international community should assist them to fulfil this duty, and that the international community should take timely and decisive measures to protect populations from such crimes when their host state fails to do so. Progressing R2P from words to deeds requires international consensus about the principle’s meaning and scope. To achieve a global consensus on this, we need to better understand the position of governments around the world, including in the Asia-Pacific region, which has long been associated with an enduring commitment to a traditional concept of sovereignty. The present article contributes to such an endeavour through its three sections. The first part charts the nature of the international consensus on R2P and examines the UN secretary-general’s approach. The second looks in detail at the positions of the Asia-Pacific region’s governments on the R2P principle. The final part explores the way forward for progressing the R2P principle in the Asia-Pacific region.
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The 1967 Protocol Relating to the Status of Refugees has been described as an unnecessary addendum to the 1951 Convention Relating to the Status of Refugees. However, if the 1967 Protocol was superfluous, why did the United Nations High Commissioner for Refugees in the early 1960s insist on its development? This article seeks to establish that the 1967 Protocol was originally intended to encompass the broader concerns of African and Asian states concerning refugee populations in their region. However, the political influence upon the development of international refugee law radically altered the UNHCR's endeavour to make the 1951 Convention universally accessible.
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Charities' fundraising financial transactions should be reported in the interests of accountability, and the report should be publicly available. However, research shows that at present there is little consistency in how fundraising is defined or in how such transactions are reported, and little guidance from accounting standards. This report examines whether the current reporting of fundraising in annual financial statements by Australian charities is fit for the purposes of informing the donating public and other stakeholders, whether through the Australian Charities and Not-for-profits Commission’s registry strategy or through other means such as private ratings agencies. The authors endeavour to suggest a way forward if it is not.
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This study demonstrates a novel method for testing the hypothesis that variations in primary and secondary particle number concentration (PNC) in urban air are related to residual fuel oil combustion at a coastal port lying 30 km upwind, by examining the correlation between PNC and airborne particle composition signatures chosen for their sensitivity to the elemental contaminants present in residual fuel oil. Residual fuel oil combustion indicators were chosen by comparing the sensitivity of a range of concentration ratios to airborne emissions originating from the port. The most responsive were combinations of vanadium and sulfur concentration ([S], [V]) expressed as ratios with respect to black carbon concentration ([BC]). These correlated significantly with ship activity at the port and with the fraction of time during which the wind blew from the port. The average [V] when the wind was predominantly from the port was 0.52 ng.m-3 (87%) higher than the average for all wind directions and 0.83 ng.m-3 (280%) higher than that for the lowest vanadium yielding wind direction considered to approximate the natural background. Shipping was found to be the main source of V impacting urban air quality in Brisbane. However, contrary to the stated hypothesis, increases in PNC related measures did not correlate with ship emission indicators or ship traffic. Hence at this site ship emissions were not found to be a major contributor to PNC compared to other fossil fuel combustion sources such as road traffic, airport and refinery emissions.
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• For the purposes of this chapter, “health law” encapsulates regulation of the medical and health professions, the administration of health services and the maintenance of public health to the extent that it is connected to the provision of health services. • There are diverging views as to whether health law can be regarded as a discrete “area of law”. • Health law draws on other areas of law such as tort law, criminal law and family law. It also draws upon other disciplines, most notably medical and health ethics. • Social and economic forces have influenced the development and direction of health law, and these forces may become even more influential in the future. • The increasingly globalised world has implications for Australia's health systems and raises questions and creates commitments in respect of the international community. • Technological developments, including in respect of treatment, diagnosis and information management, create ongoing challenges for health law. • Patient rights, human rights and consumerism are increasingly key drivers in the development of health law. • Health law is significant to contemporary Australian society because of the gravity of the topics that fall within its ambit, its social relevance to so many aspects of human existence and endeavour, the important role it plays in protecting the vulnerable, and the extent to which it engages with fundamental principles of justice.