An integrated approach to cryptographic mitigation of denial-of-service attacks

Gradual authentication is a principle proposed by Meadows as a way to tackle denial-of-service attacks on network protocols by gradually increasing the confidence in clients before the server commits resources. In this paper, we propose an efficient method that allows a defending server to authenticate its clients gradually with the help of some fast-to-verify measures. Our method integrates hash-based client puzzles along with a special class of digital signatures supporting fast verification. Our hash-based client puzzle provides finer granularity of difficulty and is proven secure in the puzzle difficulty model of Chen et al. (2009). We integrate this with the fast-verification digital signature scheme proposed by Bernstein (2000, 2008). These schemes can be up to 20 times faster for client authentication compared to RSA-based schemes. Our experimental results show that, in the Secure Sockets Layer (SSL) protocol, fast verification digital signatures can provide a 7% increase in connections per second compared to RSA signatures, and our integration of client puzzles with client authentication imposes no performance penalty on the server since puzzle verification is a part of signature verification.

A dynamic approach to forecast rental growth

Numerous econometric models have been proposed for forecasting property market performance, but limited success has been achieved in finding a reliable and consistent model to predict property market movements over a five to ten year timeframe. This research focuses on office rental growth forecasts and overviews many of the office rent models that have evolved over the past 20 years. A model by DiPasquale and Wheaton is selected for testing in the Brisbane, Australia office market. The adaptation of this study did not provide explanatory variables that could assist in developing a reliable, predictive model of office rental growth. In light of this result, the paper suggests a system dynamics framework that includes an econometric model based on historical data as well as user input guidance for the primary variables. The rent forecast outputs would be assessed having regard to market expectations and probability profiling undertaken for use in simulation exercises. The paper concludes with ideas for ongoing research.

Outcomes and implications of one teacher's approach to context-based science in the middle years

In Australia, there is a crisis in science education with students becoming disengaged with canonical science in the middle years of schooling. One recent initiative that aims to improve student interest and motivation without diminishing conceptual understanding is the context-based approach. Contextual units that connect the canonical science with the students’ real world of their local community have been used in the senior years but are new in the middle years. This ethnographic study explored the learning transactions that occurred in one 9th grade science class studying a context-based Environmental Science unit for 11 weeks. Outcomes of the study and implications are discussed in this paper.

A Bayesian approach to assess interaction between known risk factors: The risk of lung cancer from exposure to asbestos and smoking

We review the literature on the combined effect of asbestos exposure and smoking on lung cancer, and explore a Bayesian approach to assess evidence of interaction. Previous approaches have focussed on separate tests for an additive or multiplicative relation. We extend these approaches by exploring the strength of evidence for either relation using approaches which allow the data to choose between both models. We then compare the different approaches.

IS-impact utility and intuitiveness : a rigorous approach to relevance

The study proposes to test the ‘IS-Impact’ index as Analytic Theory (AT). To (a) methodically evaluate the ‘relevance’ qualities of IS-Impact; namely, Utility & Intuitiveness. In so doing, to (b) document an exemplar of ‘a rigorous approach to relevance’, while (c) treating the overarching study as a higher-order case study having AT as the unit-of-analysis, and assessing adequacy of the 6 AT qualities, both for IS-Impact and for similar taxonomies. Also to (d) look beyond IS-Impact to other forms of Design Science, considering the generality of the AT qualities; and (e) further validating IS-Impact in new system organisation contexts taking account of contemporary understandings of construct theorisation, operationalization and validation.

A sustainable approach to community based rehabilitation in rural and remote Australia

This paper presents a summary of an extensive review of the health, disability and rehabilitation literature conducted for the purposes of informing the formulation of a sustainable approach to community based rehabilitation in rural and remote Australia. It begins with a review of definitions of disability and rehabilitation, which is followed by differentiating 'rehabilitation in the community' and 'community based rehabilitation'. Finally, a network of community based rehabilitation coalitions is proposed as a sustainable approach to community based rehabilitation in rural and remote Australia. Each coalition would have a community rehabilitation facilitator and community specific database of resources, as well as a register of local community rehabilitation assistants who can support the work of health professionals by providing rehabilitation interventions under the latter's direction. In this approach, rehabilitation is conceptualised as being about people's lives rather than only a series of interventions provided by health care professionals. As such, rehabilitation becomes everybody's business.

A constraints-led approach to talent development in cricket

The aim of this chapter is to increase understanding of how a sound theoretical model of the learner and learning processes informs the organisation of learning environments and effective and efficient use of practice time. Drawing on an in-depth interview with Greg Chappell, the head coach at the Centre of Excellence—the Brisbane-based centre for training and development in cricket of the Australian Institute of Sport (AIS) and Cricket Australia—it describes and explains many of the key features of non-linear pedagogy. Specifically, after backgrounding the constraints-led approach, it deals with environmental constraints; the focus of the individual and the implications of self-organisation for coaching strategies; implications for the coach–athlete relationship; manipulating constraints; representative practice; developing decision-makers and learning design including discovery and implicit learning. It then moves on to a discussion of more global issues such as the reactions of coaches and players when a constraints-led approach is introduced, before finally considering the widely held belief among coaches that approaches such as Teaching Games for Understanding (TGfU) ‘take longer’ than traditional coaching methods.

The constraints-based approach to motor learning : Implications for a non-linear pedagogy in sport and physical education

Recently, a constraints- led approach has been promoted as a framework for understanding how children and adults acquire movement skills for sport and exercise (see Davids, Button & Bennett, 2008; Araújo et al., 2004). The aim of a constraints- led approach is to identify the nature of interacting constraints that influence skill acquisition in learners. In this chapter the main theoretical ideas behind a constraints- led approach are outlined to assist practical applications by sports practitioners and physical educators in a non- linear pedagogy (see Chow et al., 2006, 2007). To achieve this goal, this chapter examines implications for some of the typical challenges facing sport pedagogists and physical educators in the design of learning programmes.

A learning-based approach to reactive security

Despite the conventional wisdom that proactive security is superior to reactive security, we show that reactive security can be competitive with proactive security as long as the reactive defender learns from past attacks instead of myopically overreacting to the last attack. Our game-theoretic model follows common practice in the security literature by making worst-case assumptions about the attacker: we grant the attacker complete knowledge of the defender’s strategy and do not require the attacker to act rationally. In this model, we bound the competitive ratio between a reactive defense algorithm (which is inspired by online learning theory) and the best fixed proactive defense. Additionally, we show that, unlike proactive defenses, this reactive strategy is robust to a lack of information about the attacker’s incentives and knowledge.