169 resultados para two-to-one trapdoor functions
em Queensland University of Technology - ePrints Archive
Resumo:
Digital signatures are often used by trusted authorities to make unique bindings between a subject and a digital object; for example, certificate authorities certify a public key belongs to a domain name, and time-stamping authorities certify that a certain piece of information existed at a certain time. Traditional digital signature schemes however impose no uniqueness conditions, so a trusted authority could make multiple certifications for the same subject but different objects, be it intentionally, by accident, or following a (legal or illegal) coercion. We propose the notion of a double-authentication-preventing signature, in which a value to be signed is split into two parts: a subject and a message. If a signer ever signs two different messages for the same subject, enough information is revealed to allow anyone to compute valid signatures on behalf of the signer. This double-signature forgeability property discourages signers from misbehaving—a form of self-enforcement—and would give binding authorities like CAs some cryptographic arguments to resist legal coercion. We give a generic construction using a new type of trapdoor functions with extractability properties, which we show can be instantiated using the group of sign-agnostic quadratic residues modulo a Blum integer; we show an additional application of these new extractable trapdoor functions to standard digital signatures.
Resumo:
To this day, realizations in the standard-model of (lossy) trapdoor functions from discrete-log-type assumptions require large public key sizes, e.g., about Θ(λ 2) group elements for a reduction from the decisional Diffie-Hellman assumption (where λ is a security parameter). We propose two realizations of lossy trapdoor functions that achieve public key size of only Θ(λ) group elements in bilinear groups, with a reduction from the decisional Bilinear Diffie-Hellman assumption. Our first construction achieves this result at the expense of a long common reference string of Θ(λ 2) elements, albeit reusable in multiple LTDF instantiations. Our second scheme also achieves public keys of size Θ(λ), entirely in the standard model and in particular without any reference string, at the cost of a slightly more involved construction. The main technical novelty, developed for the second scheme, is a compact encoding technique for generating compressed representations of certain sequences of group elements for the public parameters.
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Despite significant investment in school one-to-one device programs, little is known about which aspects of program implementation work and why. Through a comparison of two implementation models, adopter-diffusion and saturation, and using existing data from the One Laptop per Child Australia laptop program, we explored how factors of implementation may affect device diffusion, learning and educational outcomes, and program sustainability in schools. In this article we argue that more focused research into implementation of one-to-one device programs, moving beyond comparisons of “devices versus without devices,” is needed to provide reliable data to inform future program funding and advance this area of research.
Resumo:
This research paper reports on phase one of an investigation of video recorded intensive one-to-one teaching interactions with 6–7-year-old students who were in their second year of schooling in Australia and identified by the their teacher as low attaining in early number. The two-phased study from which this paper emerges was originally conducted in 1998 as part of my Bachelor of Teaching Honours (Research) program at Southern Cross University Lismore, New South Wales. That study identified teaching interactions particularly suited to one-to-one teaching in the Maths Recovery Program, a program designed for these students who were at risk of failure in early number. Since that time a great deal has not changed with limited literature available that comprehensively reports on teaching interactions in intensive one-to-one settings. Revisiting the original study is considered timely given the increasing number of withdrawal and intensive programs now funded and adopted by schools and yet, rarely reported on in terms of the effectiveness of the teaching interactions that occur in such settings. This paper then presents a discussion of a preliminary series of teaching interactions that either positively and or negatively influence an intensive one-to-one teaching and learning setting
Resumo:
Despite the significant recent growth in research relating to instrumental, vocal and composition tuition in higher education, little is known about the diversity of approaches that characterise one-to-one teaching in the Conservatoire, and what counts as optimal practice for educating 21st-century musicians. Through analysis of video-recorded one-to-one lessons that draws on a ‘bottom up’ methodology for characterising pedagogical practices (Taylor, 2012; Taylor et al, 2012), this paper provides empirical evidence about the nature of one-to-one pedagogy in one Australian institution. The research aims (1) to enable a better understanding of current one-to-one conservatoire teaching; and (2) to build and improve upon existing teaching practice using authentic insights gained through systematic investigation. The authors hope the research will lead to a better understanding of the diversity and efficacy of the pedagogical practice within the specific context in which the study was conducted, and beyond, to Conservatoire pedagogy generally.
Resumo:
The primary aim of this descriptive exploration of scientists’ life cycle award patterns is to evaluate whether awards breed further awards and identify researcher experiences after reception of the Nobel Prize. To achieve this goal, we collected data on the number of awards received each year for 50 years before and after Nobel Prize reception by all 1901–2000 Nobel laureates in physics, chemistry, and medicine or physiology. Our results indicate an increasing rate of awards before Nobel reception, reaching the summit precisely in the year of the Nobel Prize. After this pinnacle year, awards drop sharply. This result is confirmed by separate analyses of three different disciplines and by a random-effects negative binomial regression model. Such an effect, however, does not emerge for more recent Nobel laureates (1971–2000). In addition, Nobelists in medicine or physiology generate more awards shortly before and after prize reception, whereas laureates in chemistry attract more awards as time progresses.
Resumo:
Purpose The LUX-Lung 3 study investigated the efficacy of chemotherapy compared with afatinib, a selective, orally bioavailable ErbB family blocker that irreversibly blocks signaling from epidermal growth factor receptor (EGFR/ErbB1), human epidermal growth factor receptor 2 (HER2/ErbB2), and ErbB4 and has wide-spectrum preclinical activity against EGFR mutations. A phase II study of afatinib in EGFR mutation-positive lung adenocarcinoma demonstrated high response rates and progression-free survival (PFS). Patients and Methods In this phase III study, eligible patients with stage IIIB/IV lung adenocarcinoma were screened for EGFR mutations. Mutation-positive patients were stratified by mutation type (exon 19 deletion, L858R, or other) and race (Asian or non-Asian) before two-to-one random assignment to 40 mg afatinib per day or up to six cycles of cisplatin plus pemetrexed chemotherapy at standard doses every 21 days. The primary end point was PFS by independent review. Secondary end points included tumor response, overall survival, adverse events, and patient-reported outcomes (PROs). Results A total of 1,269 patients were screened, and 345 were randomly assigned to treatment. Median PFS was 11.1 months for afatinib and 6.9 months for chemotherapy (hazard ratio [HR], 0.58; 95% CI, 0.43 to 0.78; P = .001). Median PFS among those with exon 19 deletions and L858R EGFR mutations (n = 308) was 13.6 months for afatinib and 6.9 months for chemotherapy (HR, 0.47; 95% CI, 0.34 to 0.65; P = .001). The most common treatmentrelated adverse events were diarrhea, rash/acne, and stomatitis for afatinib and nausea, fatigue, and decreased appetite for chemotherapy. PROs favored afatinib, with better control of cough, dyspnea, and pain. Conclusion Afatinib is associated with prolongation of PFS when compared with standard doublet chemotherapy in patients with advanced lung adenocarcinoma and EGFR mutations.
Resumo:
Aggressive driving is considered an important road-safety concern for drivers in highly motorised countries. However, understanding of the causes and maintenance factors fundamental to aggressive driving is limited. In keeping with theoretical advances from general aggression research such as the General Aggression Model (GAM), research has begun to examine the emotional and cognitive antecedents of aggressive driving in order to better understand the underlying processes motivating aggressive driving. Early findings in the driving area have suggested that greater levels of aggression are elicited in response to an intentionally aggressive on-road event. In contrast, general aggression research suggests that greater levels of aggression are elicited in response to an ambiguous event. The current study examined emotional and cognitive responses to two hypothetical driving scenarios with differing levels of aggressive intent (intentional versus ambiguous). There was also an interest in whether factors influencing responses were different for hostile aggression (that is, where the action is intended to harm the other) versus instrumental aggression (that is, where the action is motivated by an intention to remove an impediment or attain a goal). Results were that significantly stronger negative emotion and negative attributions, as well as greater levels of threat were reported in response to the scenario which was designed to appear intentional in nature. In addition, participants were more likely to endorse an aggressive behavioural response to a situation that appeared deliberately aggressive than to one where the intention was ambiguous. Analyses to determine if greater levels of negative emotions and cognitions are able to predict aggressive responses provided different patterns of results for instrumental aggression from those for hostile aggression. Specifically, for instrumental aggression, negative emotions and negative attributions were significant predictors for both the intentional and the ambiguous scenarios. In addition, perceived threat was also a significant predictor where the other driver’s intent was clearly aggressive. However, lower rather than higher, levels of perceived threat were associated with greater endorsement of an aggressive response. For hostile aggressive behavioural responses, trait aggression was the strongest predictor for both situations. Overall the results suggest that in the driving context, instrumental aggression is likely to be a much more common response than hostile aggression. Moreover, aggressive responses are more likely in situations where another driver’s behaviour is clearly intentional rather than ambiguous. The results also support the conclusion that there may be different underlying mechanisms motivating an instrumental aggressive response to those motivating a hostile one. In addition, understanding the emotions and cognitions underlying aggressive driving responses may be helpful in predicting and intervening to reduce driving aggression. The finding that drivers appear to regard tailgating as an instrumental response is of concern since this behaviour has the potential to result in crashes.
Resumo:
One-time proxy signatures are one-time signatures for which a primary signer can delegate his or her signing capability to a proxy signer. In this work we propose two one-time proxy signature schemes with different security properties. Unlike other existing one-time proxy signatures that are constructed from public key cryptography, our proposed schemes are based one-way functions without trapdoors and so they inherit the communication and computation efficiency from the traditional one-time signatures. Although from a verifier point of view, signatures generated by the proxy are indistinguishable from those created by the primary signer, a trusted authority can be equipped with an algorithm that allows the authority to settle disputes between the signers. In our constructions, we use a combination of one-time signatures, oblivious transfer protocols and certain combinatorial objects. We characterise these new combinatorial objects and present constructions for them.
Resumo:
In 2009, Religious Education is a designated key learning area in Catholic schools in the Archdiocese of Brisbane and, indeed, across Australia. Over the years, though, different conceptualisations of the nature and purpose of religious education have led to the construction of different approaches to the classroom teaching of religion. By investigating the development of religious education policy in the Archdiocese of Brisbane from 1984 to 2003, the study seeks to trace the emergence of new discourses on religious education. The study understands religious education to refer to a lifelong process that occurs through a variety of forms (Moran, 1989). In Catholic schools, it refers both to co-curricula activities, such as retreats and school liturgies, and the classroom teaching of religion. It is the policy framework for the classroom teaching of religion that this study explores. The research was undertaken using a policy case study approach to gain a detailed understanding of how new conceptualisations of religious education emerged at a particular site of policy production, in this case, the Archdiocese of Brisbane. The study draws upon Yeatman’s (1998) description of policy as occurring “when social actors think about what they are doing and why in relation to different and alternative possible futures” (p. 19) and views policy as consisting of more than texts themselves. Policy texts result from struggles over meaning (Taylor, 2004) in which specific discourses are mobilised to support particular views. The study has a particular interest in the analysis of Brisbane religious education policy texts, the discursive practices that surrounded them, and the contexts in which they arose. Policy texts are conceptualised in the study as representing “temporary settlements” (Gale, 1999). Such settlements are asymmetrical, temporary and dependent on context: asymmetrical in that dominant actors are favoured; temporary because dominant actors are always under challenge by other actors in the policy arena; and context - dependent because new situations require new settlements. To investigate the official policy documents, the study used Critical Discourse Analysis (hereafter referred to as CDA) as a research tool that affords the opportunity for researchers to map and chart the emergence of new discourses within the policy arena. As developed by Fairclough (2001), CDA is a three-dimensional application of critical analysis to language. In the Brisbane religious education arena, policy texts formed a genre chain (Fairclough, 2004; Taylor, 2004) which was a focus of the study. There are two features of texts that form genre chains: texts are systematically linked to one another; and, systematic relations of recontextualisation exist between the texts. Fairclough’s (2005) concepts of “imaginary space” and “frameworks for action” (p. 65) within the policy arena were applied to the Brisbane policy arena to investigate the relationship between policy statements and subsequent guidelines documents. Five key findings emerged from the study. First, application of CDA to policy documents revealed that a fundamental reconceptualisation of the nature and purpose of classroom religious education in Catholic schools occurred in the Brisbane policy arena over the last twenty-five years. Second, a disjuncture existed between catechetical discourses that continued to shape religious education policy statements, and educational discourses that increasingly shaped guidelines documents. Third, recontextualisation between policy documents was evident and dependent on the particular context in which religious education occurred. Fourth, at subsequent links in the chain, actors created their own “imaginary space”, thereby altering orders of discourse within the policy arena, with different actors being either foregrounded or marginalised. Fifth, intertextuality was more evident in the later links in the genre chain (i.e. 1994 policy statement and 1997 guidelines document) than in earlier documents. On the basis of the findings of the study, six recommendations are made. First, the institutional Church should carefully consider the contribution that the Catholic school can make to the overall pastoral mission of the diocese in twenty-first century Australia. Second, policymakers should articulate a nuanced understanding of the relationship between catechesis and education with regard to the religion classroom. Third, there should be greater awareness of the connections among policies relating to Catholic schools – especially the connection between enrolment policy and religious education policy. Fourth, there should be greater consistency between policy documents. Fifth, policy documents should be helpful for those to whom they are directed (i.e. Catholic schools, teachers). Sixth, “imaginary space” (Fairclough, 2005) in policy documents needs to be constructed in a way that allows for multiple “frameworks for action” (Fairclough, 2005) through recontextualisation. The findings of this study are significant in a number of ways. For religious educators, the study highlights the need to develop a shared understanding of the nature and purpose of classroom religious education. It argues that this understanding must take into account the multifaith nature of Australian society and the changing social composition of Catholic schools themselves. Greater recognition should be given to the contribution that religious studies courses such as Study of Religion make to the overall religious development of a person. In view of the social composition of Catholic schools, there is also an issue of ecclesiological significance concerning the conceptualisation of the relationship between the institutional Catholic Church and Catholic schools. Finally, the study is of significance because of its application of CDA to religious education policy documents. Use of CDA reveals the foregrounding, marginalising, or excluding of various actors in the policy arena.
Resumo:
Boundary spanning links organisations to one another in order to create mutually beneficial relationships; it is a concept developed and used in organisational theory but rarely used to understand organisational structures in higher education (Pruitt & Schwartz, 1999). Yet understanding boundary spanning activity has the capacity to help universities respond to demands for continuous quality improvement, and to increase capacity to react to environmental uncertainty. At a time of rapid change characterised by a fluctuating economic environment, globalisation, increased mobility, and ecological issues, boundary spanning could be viewed as a key element in assisting institutions in effectively understanding and responding to such change. The literature suggests that effective boundary spanning could help universities improve organisational performance, use of infrastructure and resources, intergroup relations, leadership styles, performance and levels of job satisfaction, technology transfer, knowledge creation, and feedback processes, amongst other things. Our research aims to put a face on boundary spanning (Miller, 2008) by contextualising it within organisational systems and structures in university departments responsible for work related programs i.e. Work Integrated Learning (WIL) and Co-operative Education (Co-op). In this paper these approaches are referred to collectively as work related programs. The authors formed a research team in Victoria, British Columbia in 2009 at a sponsored international research forum, Two Days in June. The purpose of the invitation-only forum was to investigate commonalities and differences across programs and to formulate an international research agenda for work related programs over the next five to ten years. Researchers from Queensland University of Technology, University of Cincinnati, Baden-Wuerttemberg Cooperative State University, University of Ottawa,and Dublin City University agreed that further research was needed into the impact stakeholders, organisational systems, structures, policies, and practices have on departments delivering work related programs. This paper illustrates how policy and practice across the five institutions can be better understood through the lens of boundary spanning. It is argued that boundary spanning is an area of theory and practice with great applicability to a better understanding of the activity of these departments. The paper concludes by proposing topics for future research to examine how boundary spanning can be used to better understand practice and change in work related programs.
Resumo:
The purpose of this study was to explore barriers and facilitators to using CityCycle, a public bicycle share scheme in Brisbane, Australia. Focus groups were conducted with participants belonging to one of three categories. Group one consisted of infrequent and noncyclists (no bicycle riding over the past month), group two were regular bicycle riders (ridden a bicycle at least once in the past month) and group three was composed of CityCycle members. A thematic analytic method was used to analyse the data. Three main themes were found: Accessibility/spontaneity, safety and weather/topography. The lengthy sign-up process was thought to stifle the spontaneity typically thought to attract people to public bike share. Mandatory helmet legislation was thought to reduce spontaneous use. Safety was a major concern for all groups and this included a perceived lack of suitable bicycle infrastructure, as well as regular riders describing a negative attitude of some car drivers. Interestingly, CityCycle riders unanimously perceived car driver attitudes to improve when on CityCycle bicycles relative to riding on personal bicycles. Conclusions: In order to increase the popularity of the CityCycle scheme, the results of this study suggest that a more accessible, spontaneous sign-up process is required, 24/7 opening hours, and greater incentives to sign up new members and casual users, as seeing people using CityCycle appears critical to further take up.
Resumo:
Neighbourhood like the concept of liveability is usually measured by either subjective indicators using surveys of residents’ perceptions or by objective means using secondary data or relative weights for objective indicators of the urban environment. Rarely, have objective and subjective indicators been related to one another in order to understand what constitutes a liveable urban neighbourhood both spatially and behaviourally. This paper explores the use of qualitative (diaries, in-depth interviews) and quantitative (Global Positioning Systems, Geographical Information Systems mapping) liveability research data to examine the perceptions and behaviour of 12 older residents living in six high density urban areas of Brisbane. Older urban Australians are one of the two principal groups highly attracted to high density urban living. The strength of the relationship between the qualitative and quantitative measures was examined. Results of the research indicate a weak relationship between subjective and objective indicators. Linking the two methods (quantitative and qualitative) is important in obtaining a greater understanding of human behaviour and the lived world of older urban Australians and in providing a wider picture of the urban neighbourhood.
Resumo:
This book was written to serve two functions. First it is an exploration of what I have called Socratic pedagogy, a collaborative inquiry-based approach to teaching and learning suitable not only to formal educational settings such as the school classroom but to all educational settings. The term is intended to capture a variety of philosophical approaches to classroom practice that could broadly be described Socratic in form. The term ‘philosophy in schools’ is ambiguous and could refer to teaching university style philosophy to high school students or to the teaching of philosophy and logic or critical reasoning in senior years of high school. It is also used to describe the teaching of philosophy in schools generally. In the early and middle phases of schooling the term philosophy for children is often used. But this too is ambiguous as the name was adopted from Matthew Lipman’s Philosophy for Children curriculum that he and his colleagues at the Institute for the Advancement of Philosophy for Children developed. In Britain the term ‘philosophy with children’ is sometimes employed to mark two methods of teaching that have Socratic roots but have distinct differences, namely Philosophy for Children and Socratic Dialogue developed by Leonard Nelson. The use of the term Socratic pedagogy and its companion term Socratic classroom (to refer to the kind of classroom that employs Socratic teaching) avoids the problem of distinguishing between various approaches to philosophical inquiry in the Socratic tradition but also separates it from the ‘study of philosophy’, such as university style philosophy or other approaches which place little or no emphasis on collaborative inquiry based teaching and learning. The second function builds from the first. It is to develop an effective framework for understanding the relationship between what I call the generative, evaluative and connective aspects of communal dialogue, which I think are necessary to the Socratic notion of inquiry. In doing so it is hoped that this book offers some way to show how philosophy as inquiry can contribute to educational theory and practice, while also demonstrating how it can be an effective way to approach teaching and learning. This has meant striking a balance between speaking to philosophers and to teachers and educators together, with the view that both see the virtues of such a project. In the strictest sense this book is not philosophy of education, insofar as its chief focus is not on the analysis of concepts or formulation of definitions specific to education with the aim of formulating directives that guide educational practice. It relinquishes the role of philosopher as ‘spectator’, to one of philosopher ‘immersed in matter’ – in this case philosophical issues in education, specifically those related to philosophical inquiry, pedagogy and classroom practice. Put another way, it is a book about philosophical education.