154 resultados para rational interpolants
Resumo:
Market failures involving the sale of complex merchandise, such as residential property, financial products and credit, have principally been attributed to information asymmetries. Existing legislative and regulatory responses were developed having regard to consumer protection policies based on traditional economic theories that focus on the notion of the ‘rational consumer’. Governmental responses therefore seek to impose disclosure obligations on sellers of complex goods or products to ensure that consumers have sufficient information upon which to make a decision. Emergent research, based on behavioural economics, challenges traditional ideas and instead focuses on the actual behaviour of consumers. This approach suggests that consumers as a whole do not necessarily benefit from mandatory disclosure because some, if not most, consumers do not pay attention to the disclosed information before they make a decision to purchase. The need for consumer policies to take consumer characteristics and behaviour into account is being increasingly recognised by governments, and most recently in the policy framework suggested by the Australian Productivity Commission
Resumo:
The theories of parents about the cause of their children's leukaemia have been documented in the course of a case-control study. From a sample of 175 children who were diagnosed as having acute lymphoblastic leukaemia, 91.4% of their parents put forward their theories. Some of these theories were related clearly to material that had been published and therefore had some scientific validity. Other theories often had no apparent scientific basis. Persons who are involved in the care of children with leukaemia should be aware of the wide variety of theories that are held by their parents so that they may provide counselling which could be of help in the relief of feelings of anxiety or guilt among the parents. Parents should always be afforded the opportunity to put forward their own theories so that they may be discussed on a rational basis. It is conceivable that some parents might put forward new hypotheses about leukaemogenesis that could be tested scientifically.
Resumo:
This thesis is about the derivation of the addition law on an arbitrary elliptic curve and efficiently adding points on this elliptic curve using the derived addition law. The outcomes of this research guarantee practical speedups in higher level operations which depend on point additions. In particular, the contributions immediately find applications in cryptology. Mastered by the 19th century mathematicians, the study of the theory of elliptic curves has been active for decades. Elliptic curves over finite fields made their way into public key cryptography in late 1980’s with independent proposals by Miller [Mil86] and Koblitz [Kob87]. Elliptic Curve Cryptography (ECC), following Miller’s and Koblitz’s proposals, employs the group of rational points on an elliptic curve in building discrete logarithm based public key cryptosystems. Starting from late 1990’s, the emergence of the ECC market has boosted the research in computational aspects of elliptic curves. This thesis falls into this same area of research where the main aim is to speed up the additions of rational points on an arbitrary elliptic curve (over a field of large characteristic). The outcomes of this work can be used to speed up applications which are based on elliptic curves, including cryptographic applications in ECC. The aforementioned goals of this thesis are achieved in five main steps. As the first step, this thesis brings together several algebraic tools in order to derive the unique group law of an elliptic curve. This step also includes an investigation of recent computer algebra packages relating to their capabilities. Although the group law is unique, its evaluation can be performed using abundant (in fact infinitely many) formulae. As the second step, this thesis progresses the finding of the best formulae for efficient addition of points. In the third step, the group law is stated explicitly by handling all possible summands. The fourth step presents the algorithms to be used for efficient point additions. In the fifth and final step, optimized software implementations of the proposed algorithms are presented in order to show that theoretical speedups of step four can be practically obtained. In each of the five steps, this thesis focuses on five forms of elliptic curves over finite fields of large characteristic. A list of these forms and their defining equations are given as follows: (a) Short Weierstrass form, y2 = x3 + ax + b, (b) Extended Jacobi quartic form, y2 = dx4 + 2ax2 + 1, (c) Twisted Hessian form, ax3 + y3 + 1 = dxy, (d) Twisted Edwards form, ax2 + y2 = 1 + dx2y2, (e) Twisted Jacobi intersection form, bs2 + c2 = 1, as2 + d2 = 1, These forms are the most promising candidates for efficient computations and thus considered in this work. Nevertheless, the methods employed in this thesis are capable of handling arbitrary elliptic curves. From a high level point of view, the following outcomes are achieved in this thesis. - Related literature results are brought together and further revisited. For most of the cases several missed formulae, algorithms, and efficient point representations are discovered. - Analogies are made among all studied forms. For instance, it is shown that two sets of affine addition formulae are sufficient to cover all possible affine inputs as long as the output is also an affine point in any of these forms. In the literature, many special cases, especially interactions with points at infinity were omitted from discussion. This thesis handles all of the possibilities. - Several new point doubling/addition formulae and algorithms are introduced, which are more efficient than the existing alternatives in the literature. Most notably, the speed of extended Jacobi quartic, twisted Edwards, and Jacobi intersection forms are improved. New unified addition formulae are proposed for short Weierstrass form. New coordinate systems are studied for the first time. - An optimized implementation is developed using a combination of generic x86-64 assembly instructions and the plain C language. The practical advantages of the proposed algorithms are supported by computer experiments. - All formulae, presented in the body of this thesis, are checked for correctness using computer algebra scripts together with details on register allocations.
Resumo:
Following Youngjohn, Lees-Haley, and Binder's (1999) comment on Johnson and Lesniak-Karpiak's (1997) study that warnings lead to more subtle malingering, researchers have sought to better understand warning effects. However, such studies have been largely atheoretical and may have confounded warning and coaching. This study examined the effect on malingering of a warning that was based on criminological-sociological concepts derived from the rational choice model of deterrence theory. A total of 78 participants were randomly assigned to a control group, an unwarned simulator group, or one of two warned simulator groups. The warning groups comprised low- and high-level conditions depending on warning intensity. Simulator participants received no coaching about how to fake tests. Outcome variables were scores derived from the Test of Memory Malingering and Wechsler Memory Scale-III. When the rate of malingering was compared across the four groups, a high-level warning effect was found such that warned participants were significantly less likely to exaggerate than unwarned simulators. In an exploratory follow-up analysis, the warned groups were divided into those who reported malingering and those who did not report malingering, and the performance of these groups was compared to that of unwarned simulators and controls. Using this approach, results showed that participants who were deterred from malingering by warning performed no worse than controls. However, on a small number of tests, self-reported malingerers in the low-level warning group appeared less impaired than unwarned simulators. This pattern was not observed in the high-level warning condition. Although cautious interpretation of findings is necessitated by the exploratory nature of some analyses, overall results suggest that using a carefully designed warning may be useful for reducing the rate of malingering. The combination of some noteworthy effect sizes, despite low power and the small size of some groups, suggests that further investigation of the effects of warnings needs to continue to determine their effect more fully.
Resumo:
This thesis addresses the contemporary issue of the control, restoration and potential for reuse of State Government-owned heritage properties with commercial potential. It attempts to reconcile the sometimes competing interests of the range of stakeholders in such properties, particularly those seeking to maximise economic performance and return on one hand and community expectations for heritage preservation and exhibition on the other. The matters are approached principally from the Government's position as asset owner/manager. It includes research into a number of key elements - including statutory, physical and economic parameters and an analysis of the legitimate requirements of all stakeholders. The thesis also recognises the need for innovation in approach and for the careful structuring and pre-planning of proposals on a project-by-project basis. On the matter of innovation, four case studies are included in the thesis to exhibit some approaches and techniques that have already been employed in addressing these issues. From this research base, a series of deductions at both a macro and micro level are established and a model for a rational decision-making process for dealing with such projects is developed as a major outcome of the work. Finally, the general model is applied to a specific project, the currently unused Port Office heritage site in the Brisbane Central Business District.
Resumo:
In open railway access markets, a train service provider (TSP) negotiates with an infrastructure provider (IP) for track access rights. This negotiation has been modeled by a multi-agent system (MAS) in which the IP and TSP are represented by separate software agents. One task of the IP agent is to generate feasible (and preferably optimal) track access rights, subject to the constraints submitted by the TSP agent. This paper formulates an IP-TSP transaction and proposes a branch-and-bound algorithm for the IP agent to identify the optimal track access rights. Empirical simulation results show that the model is able to emulate rational agent behaviors. The simulation results also show good consistency between timetables attained from the proposed methods and those derived by the scheduling principles adopted in practice.
Resumo:
Introduction: Floods are the most common hazard to cause disasters and have led to extensive morbidity and mortality throughout the world. The impact of floods on the human community is related directly to the location and topography of the area, as well as human demographics and characteristics of the built environment. Objectives: The aim of this study is to identify the health impacts of disasters and the underlying causes of health impacts associated with floods. A conceptual framework is developed that may assist with the development of a rational and comprehensive approach to prevention, mitigation, and management. Methods: This study involved an extensive literature review that located >500 references, which were analyzed to identify common themes, findings, and expert views. The findings then were distilled into common themes. Results: The health impacts of floods are wide ranging, and depend on a number of factors. However, the health impacts of a particular flood are specific to the particular context. The immediate health impacts of floods include drowning, injuries, hypothermia, and animal bites. Health risks also are associated with the evacuation of patients, loss of health workers, and loss of health infrastructure including essential drugs and supplies. In the mediumterm, infected wounds, complications of injury, poisoning, poor mental health, communicable diseases, and starvation are indirect effects of flooding. In the long-term, chronic disease, disability, poor mental health, and poverty-related diseases including malnutrition are the potential legacy. Conclusions: This article proposes a structured approach to the classification of the health impacts of floods and a conceptual framework that demonstrates the relationships between floods and the direct and indirect health consequences.
Resumo:
Aim: There are issues surrounding the apparent decline and devaluing of cooking skills in the population, potential health impacts and the role of dietitians. The present paper aims to outline several arguments and raise questions on the relationship between cooking and dietetics.---------- Methods: Evidence from dietetics and nutrition journals and other sources is used to develop positions for dietetics and its relationship to cooking and cooking skills. ---------- Results: The historical relationship between dietetics and home economics has seen dietetics professionally distance itself by its scientific education on food and nutrition, rather than actual involvement with cooking. In pursuing this rational scientific approach there are concerns that dietitians have inadvertently supported the growth of the functional and convenience food market, particularly given the demise of home economics as a skill-based curricula in schools in several states. There is a need to consider what role cooking skills could have in dietetics training as a professional competency for practice, particularly for public health interventions. This is in the light of Commonwealth government funding that is legitimising cooking skill interventions as a policy response to obesity. There may be a role for dietitians to develop partnerships and train a new professional category or paraprofessionals and/or peer educators to deliver cooking skill interventions. ---------- Conclusion: There is a need for research on dietitian's views and use of cooking skill interventions. This would help answer whether we should consider cooking and cooking skills as part of our professional practice and whether cooking should be a dietetic competency.
Resumo:
Background: Patterns of diagnosis and management for men diagnosed with prostate cancer in Queensland, Australia, have not yet been systematically documented and so assumptions of equity are untested. This longitudinal study investigates the association between prostate cancer diagnostic and treatment outcomes and key area-level characteristics and individual-level demographic, clinical and psychosocial factors.---------- Methods/Design: A total of 1064 men diagnosed with prostate cancer between February 2005 and July 2007 were recruited through hospital-based urology outpatient clinics and private practices in the centres of Brisbane, Townsville and Mackay (82% of those referred). Additional clinical and diagnostic information for all 6609 men diagnosed with prostate cancer in Queensland during the study period was obtained via the population-based Queensland Cancer Registry. Respondent data are collected using telephone and self-administered questionnaires at pre-treatment and at 2 months, 6 months, 12 months, 24 months, 36 months, 48 months and 60 months post-treatment. Assessments include demographics, medical history, patterns of care, disease and treatment characteristics together with outcomes associated with prostate cancer, as well as information about quality of life and psychological adjustment. Complementary detailed treatment information is abstracted from participants’ medical records held in hospitals and private treatment facilities and collated with health service utilisation data obtained from Medicare Australia. Information about the characteristics of geographical areas is being obtained from data custodians such as the Australian Bureau of Statistics. Geo-coding and spatial technology will be used to calculate road travel distances from patients’ residences to treatment centres. Analyses will be conducted using standard statistical methods along with multilevel regression models including individual and area-level components.---------- Conclusions: Information about the diagnostic and treatment patterns of men diagnosed with prostate cancer is crucial for rational planning and development of health delivery and supportive care services to ensure equitable access to health services, regardless of geographical location and individual characteristics. This study is a secondary outcome of the randomised controlled trial registered with the Australian New Zealand Clinical Trials Registry (ACTRN12607000233426)
Resumo:
The last decade has seen an increase in research on the experience of immigrant nurses. There are two prevailing approaches in this body of work. One is a focus on the positive or negative aspects of the experience, and the other, a depiction of the experience as a linear movement from struggle to a comfortable state. Based on our study findings on the experience of China educated nurses working in Australia, this study proposes that the concept of ambivalence is more appropriate in portraying the experience of immigrant nurses. Several sources of ambivalence experienced by the participants are represented: a disparity between expectation and reality, conflicting social and cultural norms, the dual reference points of comparison, divergent interests within families, and a sense that although it is unsatisfactory, it is hard to go back. We argue that immigration generates various forms of ambivalence and immigrant nurses must live with more or less ambivalence. The notion of ambivalence can explain a range of behaviours and situations beyond the scope of rational-choice explanations. To date, ambivalence as a theoretical concept in understanding the experience of immigrant nurses has been either ignored or insufficiently addressed in the literature.
Resumo:
In line with accepted decision making theory, individuals engage in rational decision making. Decisions made under conditions of bounded rationality may have serious adverse consequences. Employees making decisions on behalf of their employer are often faced with situations where perfect and complete information is not available, and time is limited. Under such conditions, we posit that employees will make decisions that are increasingly bounded. At its most extreme neither time nor information is available to make a decision and rational decision making, bounded or not, reaches its limits. Many authors suggest that this is the point at which improvisation takes place. Although opinion in the literature is mixed regarding the efficacy of improvised decisions, we argue that improvised decisions place the organisation at considerable risk and as a consequence are undesirable.
Resumo:
The ‘anti- of ‘(Anti)Queer’ is a queer anti. In particle physics, a domain of science which was for a long time peddled as ultimately knowable, rational and objective, the postmodern turn has made everything queer (or chaotic, as the scientific version of this turn is perhaps more commonly named). This is a world where not only do two wrongs not make a right, but a negative and positive do not calmly cancel each other out to leave nothing, as mathematics might suggest. When matter meets with anti-matter, the resulting explosion can produce not only energy - heat and light? - but new matter. We live in a world whose very basics are no longer the electron and the positron, but an ever proliferating number of chaotic, unpredictable - queer? - subatomic particles. Some are ‘charmed’, others merely ‘strange’ . Weird science indeed. The ‘Anti-’ of ‘Anti-queer’ does not place itself neatly into binaries. This is not a refutation of all that queer has been or will be. It is explicitly a confrontation, a challenge, an attempt to take seriously not only the claims made for queer but the potent contradictions and silences which stand proudly when any attempt is made to write a history of the term. Specifically, ‘Anti-Queer’ is not Beyond Queer, the title of Bruce Bawer’s 1996 book which calmly and self-confidently explains the failings of queer, extols a return to a liberal political theory of cultural change and places its own marker on queer as a movement whose purpose has been served. We are not Beyond Queer. And if we are Anti-Queer, it is only to challenge those working in the arena to acknowledge and work with some of the facts of the movement’s history whose productivity has been erased with a gesture which has, proved, bizarrely, to be reductive and homogenising.
Resumo:
The kallikreins and kallikrein-related peptidases are serine proteases that control a plethora of developmental and homeostatic phenomena, ranging from semen liquefaction to skin desquamation and blood pressure. The diversity of roles played by kallikreins has stimulated considerable interest in these enzymes from the perspective of diagnostics and drug design. Kallikreins already have well-established credentials as targets for therapeutic intervention and there is increasing appreciation of their potential both as biomarkers and as targets for inhibitor design. Here, we explore the current status of naturally occurring kallikrein protease-inhibitor complexes and illustrate how this knowledge can interface with strategies for rational re-engineering of bioscaffolds and design of small-molecule inhibitors.
Resumo:
Columns are one of the key load bearing elements that are highly susceptible to vehicle impacts. The resulting severe damages to columns may leads to failures of the supporting structure that are catastrophic in nature. However, the columns in existing structures are seldom designed for impact due to inadequacies of design guidelines. The impact behaviour of columns designed for gravity loads and actions other than impact is, therefore, of an interest. A comprehensive investigation is conducted on reinforced concrete column with a particular focus on investigating the vulnerability of the exposed columns and to implement mitigation techniques under low to medium velocity car and truck impacts. The investigation is based on non-linear explicit computer simulations of impacted columns followed by a comprehensive validation process. The impact is simulated using force pulses generated from full scale vehicle impact tests. A material model capable of simulating triaxial loading conditions is used in the analyses. Circular columns adequate in capacity for five to twenty story buildings, designed according to Australian standards are considered in the investigation. The crucial parameters associated with the routine column designs and the different load combinations applied at the serviceability stage on the typical columns are considered in detail. Axially loaded columns are examined at the initial stage and the investigation is extended to analyse the impact behaviour under single axis bending and biaxial bending. The impact capacity reduction under varying axial loads is also investigated. Effects of the various load combinations are quantified and residual capacity of the impacted columns based on the status of the damage and mitigation techniques are also presented. In addition, the contribution of the individual parameter to the failure load is scrutinized and analytical equations are developed to identify the critical impulses in terms of the geometrical and material properties of the impacted column. In particular, an innovative technique was developed and introduced to improve the accuracy of the equations where the other techniques are failed due to the shape of the error distribution. Above all, the equations can be used to quantify the critical impulse for three consecutive points (load combinations) located on the interaction diagram for one particular column. Consequently, linear interpolation can be used to quantify the critical impulse for the loading points that are located in-between on the interaction diagram. Having provided a known force and impulse pair for an average impact duration, this method can be extended to assess the vulnerability of columns for a general vehicle population based on an analytical method that can be used to quantify the critical peak forces under different impact durations. Therefore the contribution of this research is not only limited to produce simplified yet rational design guidelines and equations, but also provides a comprehensive solution to quantify the impact capacity while delivering new insight to the scientific community for dealing with impacts.