Modelling client puzzles and denial-of-service resistant protocols

Denial-of-service (DoS) attacks are a growing concern to networked services like the Internet. In recent years, major Internet e-commerce and government sites have been disabled due to various DoS attacks. A common form of DoS attack is a resource depletion attack, in which an attacker tries to overload the server's resources, such as memory or computational power, rendering the server unable to service honest clients. A promising way to deal with this problem is for a defending server to identify and segregate malicious traffic as earlier as possible. Client puzzles, also known as proofs of work, have been shown to be a promising tool to thwart DoS attacks in network protocols, particularly in authentication protocols. In this thesis, we design efficient client puzzles and propose a stronger security model to analyse client puzzles. We revisit a few key establishment protocols to analyse their DoS resilient properties and strengthen them using existing and novel techniques. Our contributions in the thesis are manifold. We propose an efficient client puzzle that enjoys its security in the standard model under new computational assumptions. Assuming the presence of powerful DoS attackers, we find a weakness in the most recent security model proposed to analyse client puzzles and this study leads us to introduce a better security model for analysing client puzzles. We demonstrate the utility of our new security definitions by including two hash based stronger client puzzles. We also show that using stronger client puzzles any protocol can be converted into a provably secure DoS resilient key exchange protocol. In other contributions, we analyse DoS resilient properties of network protocols such as Just Fast Keying (JFK) and Transport Layer Security (TLS). In the JFK protocol, we identify a new DoS attack by applying Meadows' cost based framework to analyse DoS resilient properties. We also prove that the original security claim of JFK does not hold. Then we combine an existing technique to reduce the server cost and prove that the new variant of JFK achieves perfect forward secrecy (the property not achieved by original JFK protocol) and secure under the original security assumptions of JFK. Finally, we introduce a novel cost shifting technique which reduces the computation cost of the server significantly and employ the technique in the most important network protocol, TLS, to analyse the security of the resultant protocol. We also observe that the cost shifting technique can be incorporated in any Diffine{Hellman based key exchange protocol to reduce the Diffie{Hellman exponential cost of a party by one multiplication and one addition.

Pre-service Physical Education teachers and concerns regarding their ability to successfully facilitate school-based physical activity promotion strategies

Regular physical activity (PA) in youth has numerous immediate and long-term health benefits. With several studies indicating low levels of youth PA globally, schools settings have become increasingly critical settings for youth health promotion strategies. The role of physical education (PE) teachers has long been considered central to the facilitation of such strategies. However, PE teachers have a selfreported lack of knowledge, skills, understanding, and competence to successfully implement these strategies. Tertiary education programs are fundamental to adequately preparing, and shaping the attitudes and philosophies of future PE teachers towards their involvement within these programs. The aim of this investigation was to explore the beliefs and perceptions of future secondary school PE teachers, regarding their potential roles in future school-based programs designed to promote student PA. Fifty-seven (21 males and 36 females) pre-service PE teachers completed a series of open-ended survey questions concerning their perceptions towards participating in school-based PA promotion programs both as preservice during practicum, and prospectively as practising teachers. Responses were analysed thematically. Participants responded both positively and enthusiastically to both questions. Concerns regarding time, and the intention or expectation to participate in such programs were also key themes for pre-service and practicing teacher participation respectively. Critically in this study, participants did not identify any limitations which may impact upon their ability to successfully promote youth PA in school settings. This may indicate that participants have misconceptions regarding their ability to fulfil this role, or conversely, the deficiency of current PE teachers regarding school-based PA promotion has been recognised by the tertiary institution, and addressed to adequately prepare its students. School-based PA promotion is an integral element of pre-service PE teacher education, and ongoing professional development of practicing PE teachers. This trend is expected to continue in the future, in order to address ongoing public health concerns.

Urban transit quality of service : user perception and behaviour

Despite its potential multiple contributions to sustainable policy objectives, urban transit is generally not widely used by the public in terms of its market share compared to that of automobiles, particularly in affluent societies with low-density urban forms like Australia. Transit service providers need to attract more people to transit by improving transit quality of service. The key to cost-effective transit service improvements lies in accurate evaluation of policy proposals by taking into account their impacts on transit users. If transit providers knew what is more or less important to their customers, they could focus their efforts on optimising customer-oriented service. Policy interventions could also be specified to influence transit users’ travel decisions, with targets of customer satisfaction and broader community welfare. This significance motivates the research into the relationship between urban transit quality of service and its user perception as well as behaviour. This research focused on two dimensions of transit user’s travel behaviour: route choice and access arrival time choice. The study area chosen was a busy urban transit corridor linking Brisbane central business district (CBD) and the St. Lucia campus of The University of Queensland (UQ). This multi-system corridor provided a ‘natural experiment’ for transit users between the CBD and UQ, as they can choose between busway 109 (with grade-separate exclusive right-of-way), ordinary on-street bus 412, and linear fast ferry CityCat on the Brisbane River. The population of interest was set as the attendees to UQ, who travelled from the CBD or from a suburb via the CBD. Two waves of internet-based self-completion questionnaire surveys were conducted to collect data on sampled passengers’ perception of transit service quality and behaviour of using public transit in the study area. The first wave survey is to collect behaviour and attitude data on respondents’ daily transit usage and their direct rating of importance on factors of route-level transit quality of service. A series of statistical analyses is conducted to examine the relationships between transit users’ travel and personal characteristics and their transit usage characteristics. A factor-cluster segmentation procedure is applied to respodents’ importance ratings on service quality variables regarding transit route preference to explore users’ various perspectives to transit quality of service. Based on the perceptions of service quality collected from the second wave survey, a series of quality criteria of the transit routes under study was quantitatively measured, particularly, the travel time reliability in terms of schedule adherence. It was proved that mixed traffic conditions and peak-period effects can affect transit service reliability. Multinomial logit models of transit user’s route choice were estimated using route-level service quality perceptions collected in the second wave survey. Relative importance of service quality factors were derived from choice model’s significant parameter estimates, such as access and egress times, seat availability, and busway system. Interpretations of the parameter estimates were conducted, particularly the equivalent in-vehicle time of access and egress times, and busway in-vehicle time. Market segmentation by trip origin was applied to investigate the difference in magnitude between the parameter estimates of access and egress times. The significant costs of transfer in transit trips were highlighted. These importance ratios were applied back to quality perceptions collected as RP data to compare the satisfaction levels between the service attributes and to generate an action relevance matrix to prioritise attributes for quality improvement. An empirical study on the relationship between average passenger waiting time and transit service characteristics was performed using the service quality perceived. Passenger arrivals for services with long headways (over 15 minutes) were found to be obviously coordinated with scheduled departure times of transit vehicles in order to reduce waiting time. This drove further investigations and modelling innovations in passenger’ access arrival time choice and its relationships with transit service characteristics and average passenger waiting time. Specifically, original contributions were made in formulation of expected waiting time, analysis of the risk-aversion attitude to missing desired service run in the passengers’ access time arrivals’ choice, and extensions of the utility function specification for modelling passenger access arrival distribution, by using complicated expected utility forms and non-linear probability weighting to explicitly accommodate the risk of missing an intended service and passenger’s risk-aversion attitude. Discussions on this research’s contributions to knowledge, its limitations, and recommendations for future research are provided at the concluding section of this thesis.

The Foxtel-BBC deal : implications for Australian television and content

The ABC’s 50-year TV partnership with the BBC is at breaking point after a landmark deal between the British broadcaster and pay TV provider Foxtel was announced in April 2013. Under the new deal Foxtel will host a new BBC channel that will screen first-run, “fast-tracked” British programming, meaning ABC viewers will no longer have free-to-air access to popular shows such as Silent Witness and The Thick of It. The deal between Foxtel and the BBC’s commercial arm, BBC Worldwide, has major implications not only for the two partners, but also for the ABC and potentially for Australian screen content.

Designing an innovative approach to engage students in learning science : the evolving case of hybridized writing

Innovations are usually attributed to ideas generated in the minds of individuals. As we reflect upon the evolving design of an online project to engage students in learning science through hybridized writing activities we propose a more distributed view of the process of innovative design. That is, our experience suggests ideas are generated in the activity of interacting with human and material resources that expand and constrain possibilities. This project is innovative in that it is a new educational response to the problem of disengagement of students in science, and has proven to be effective in changing classroom practice and improving students’ scientific literacy. In this chapter, we identify the antecedents and trace the evolution of the project. This account illuminates the innovative design process, presents a summary of the evidence for the effectiveness of the project, and identifies future directions for further development and research. Keywords: Science learning, hybridized writing, case study, innovative approach

Valuing student and community voices in the university : action research as a framework for community service-learning

The Community Service-learning Lab (the Lab) was initiated as a university-wide service-learning experience at an Australian university. The Lab engages students, academics, and key community organisations in interdisciplinary action research projects to support student learning and to explore complex and ongoing problems nominated by the community partners. The current study uses feedback from the first offering of the Lab and focuses on exploring student experiences of the service learning project using an action research framework. Student reflections on this experience have revealed some positive outcomes of the Lab such as an appreciation for positive and strengths-based change. These outcomes are corroborated by collected reflections from community partners and academics. The students also identified challenges balancing the requirements for assessment and their goals to serve the community partner’s needs. This feedback has provided vital information for the academic team, highlighting the difficulties in balancing the agenda of the academic framework and the desire to give students authentic experiences.

It started with a KISS

This is the essay prepared for the exhibition titled 'Hot Chocolate' held at the SASA Gallery, Adelaide, South Australia, 24 October - 29 November, 2012. Below are the words that start the essay and which provide a glimpse of the artworks in the exhibition. By agreeing to work together in this exhibition, the artists in Hot Chocolate delivered across an eclectic assortment of academic enquiry: • the politics of identity • the politics of desire • fetishisation of racial and othered bodies • origin and place • the politics of skin • events, moments, and ephemerality • need We too, talked, laughed, cried and worked through these issues in relation to the artworks submitted, including Pamela’s work, and to the theory and literature we have read and utilised in our words with each other and communities. We begin this piece by reflecting on the writings of bell hooks, whose words kissed us awake and stirred us at the start of our respective formal research journeys. We align her words with some of our activism, advocacy, academic and community work. We will weave the magical lyrics from the 1970s iconic band Hot Chocolate throughout this essay.

Usability extensions for the worklet service

The YAWL Worklet Service is an effective approach to facilitating dynamic flexibility and exception handling in workflow processes. Recent additions to the Service extend its capabilities through a programming interface that provides easier access to rules storage and evaluation, and an event server that notifies listening servers and applications when exceptions are detected, which together serve enhance the functionality and accessibility of the Service's features and expand its usability to new potential domains.

Something’s coming, something good: Identifying TPACK competence in pre-service teachers’ analyses of learning objects

There is a song at the beginning of the musical, West Side Story, where the character Tony sings that “something’s coming, something good.” The song is an anthem of optimism, brimming with promise. This paper is about the long-held promise of information and communication technology (ICT) to transform teaching and learning, to modernise the learning environment of the classroom, and to create a new digital pedagogy. But much of our experience to date in the schooling sector tells more of resistance and reaction than revolution, of more of the same but with a computer in the corner and of ICT activities as unwelcome time-fillers/time-wasters. Recently, a group of pre-service teachers in a postgraduate primary education degree in an Australian university were introduced to learning objects in an ICT immersion program. Their analyses and related responses, as recorded in online journals, have here been interpreted in terms of TPACK (Technological Pedagogical and Content Knowledge). Against contemporary observation, these students generally displayed high levels of competence and highly positive dispositions of students to the integration of ICT in their future classrooms. In short, they displayed the same optimism and confidence as the fictional “Tony” in believing that something good was coming.

Rethinking the literacy capabilities of pre-service primary teachers in testing times

As a group of committed literacy teacher educators from five universities across three Australian states, the authors bring professional critique to the problematic issue of what counts in current and possible future measures of pre-service teachers’ literacy capacity. In times when normalising models of literacy assessment ignore innovative developments in technologies, we provide an example of what is happening at the ‘chalk-face’ of literacy teacher education. This paper describes a study that demonstrates how responsible alignment of teacher accreditation requirements with a scholarly impetus to incorporate digital literacies to prepare pre-service teachers will help address changing educational needs and practices (AITSL 2012; Gillen & Barton 2010; Hattie 2003; Johnson, Smith, Willis, Levine & Haywood 2011; Klein 2006; Masny & Cole 2012; OECD 2011).

Pragmatism and precision : psychology in the service of civil litigation

While forensic psychology is commonly associated with the criminal and family law domains, its ambit to offer skills and knowledge at the legal interface also makes it particularly suited to the civil law domain. At this time, civil law is arguably the least represented legislative area in terms of psychological research and professional commentary. However, it is also a broad area, with its very breadth providing scope for research consideration, as urged by Greene. The purposes of this article are (1) to review the broad role of the psychologist in the conduct of civil litigation matters in Australia, (2) to assist the novice to the area by indicating a non-exhaustive list of potentially ambiguous terms and concepts common to the conduct of professional practice, and; (3) to highlight, as an example, one area of practice not only where legal direction demands professional pragmatism but also where opportunity arises for psychological research to vitally address a major social issue.

Towards a model for student selection in clinical psychology

Background Selection of candidates for clinical psychology programmes is arguably the most important decision made in determining the clinical psychology workforce. However, there are few models to inform the development of selection tools to support selection procedures. The study, using a factor analytic structure, has operationalised the model predicting applicants' capabilities. Method Eighty-eight clinical applicants for entry into a postgraduate clinical psychology programme were assessed on a series of tasks measuring eight capabilities: guided reflection, communication skills, ethical decision making, writing, conceptual reasoning, empathy, and awareness of mind and self-observation. Results Factor analysis revealed three capabilities: labelled “awareness” accounting for 35.71% of variance; “reflection” accounting for 20.56%; and “reasoning” accounting for 18.24% of variance. Fourth year grade point average (GPA) did not correlate with performance on any of the selection capabilities other than a weak correlation with performance on the ethics capability. Conclusions Eight selection capabilities are identified for the selection of candidates independent of GPA. While the model is tentative, it is hoped that the findings will stimulate the development and validation of assessment procedures with good predictive validity which will benefit the training of clinical psychologists and, ultimately, effective service delivery.

Communicating personal amnesty : a model for health promotion in an Australian disability context

Currently pathological and illness-centric policy surrounds the evaluation of the health status of a person experiencing disability. In this research partnerships were built between disability service providers, community development organizations and disability arts organizations to build a translational evaluative methodology prior to implementation of an arts-based workshop that was embedded in a strengths-based approach to health and well-being. The model consisted of three foci: participation in a pre-designed drama-based workshop program; individualized assessment and evaluation of changing health status; and longitudinal analysis of participants changing health status in their public lives following the culmination of the workshop series. Participants (n = 15) were recruited through disability service providers and disability arts organizations to complete a 13-week workshop series and public performance. The study developed accumulative qualitative analysis tools and member-checking methods specific to the communication systems used by individual participants. Principle findings included increased confidence for verbal and non-verbal communicators; increased personal drive, ambition and goal-setting; increased arts-based skills including professional engagements as artists; demonstrated skills in communicating perceptions of health status to private and public spheres. Tangential positive observations were evident in the changing recreational, vocational and educational activities participants engaged with pre- and post- the workshop series; participants advocating for autonomous accommodation and health provision and changes in the disability service staff's culture. The research is an example of translational health methodologies in disability studies.

Writing the visible page : a multimodal approach to graphic devices in literary fiction

This practice-led project has two outcomes: a collection of short stories titled 'Corkscrew Section', and an exegesis. The short stories combine written narrative with visual elements such as images and typographic devices, while the exegesis analyses the function of these graphic devices within adult literary fiction. My creative writing explores a variety of genres and literary styles, but almost all of the stories are concerned with fusing verbal and visual modes of communication. The exegesis adopts the interpretive paradigm of multimodal stylistics, which aims to analyse graphic devices with the same level of detail as linguistic analysis. Within this framework, the exegesis compares and extends previous studies to develop a systematic method for analysing how the interactions between language, images and typography create meaning within multimodal literature.

Quality assessment of service bundles for governmental one-stop portals : a literature review

Service bundles, in the context of e-government, are used to group services together that relate to a certain citizen need. These bundles can then be presented on a governmental one-stop portal to structure the available service offerings according to citizen expectations. In order to ensure that citizens utilise the one-stop portal and comprised service bundles for future transactions, the quality of these service bundles needs to be managed and maximised accordingly. Consequently, models and tools that focus on assessing service bundle quality play an important role, when it comes to increasing or retaining usage behaviour of citizens. This study focuses on providing a rigorous and structured literature review of e-government outlets with regards to their coverage of service bundle quality and e-service quality themes. The study contributes to academia and practice by providing a framework that allows structuring and classifying existing studies relevant for the assessment of quality for government portals. Furthermore, this study provides insights into the status quo of quality models that can be used by governments to assess the quality of their service bundles. Directions for future research and limitations of the present study are provided as well.