136 resultados para message exchange


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J.W.Lindt’s Colonial man and Aborigine image from the GRAFTON ALBUM: “On chemistry and optics all does not depend, art must with these in triple union blend” (text from J.W. Lindt’s photographic backing card) In this paper, I follow an argument that Lindt held a position in his particular colonial environment where he was simultaneously both an insider and an outsider and that such a position may be considered prerequisite in stimulating exchange. A study of the transition of J.W. Lindt in Grafton, N.S.W. in the 1860s from a traveller to a migrant and subsequently to a professional photographer, as well as Lindt’s photographic career, which evolved through strategic action and technical approaches to photography, bears witness to his cultural relativity. One untitled photograph from this period of work constructs a unique commentary of Australian colonial life that illustrates a non-hegemonic position, particularly as it was included in one of the first albums of photographs of Aborigines that Lindt gifted to an illustrious person (in this case the Mayor of Grafton). As in his other studio constructions, props and backdrops were arranged and sitters were positioned with care, but this photograph is the only one in the album that includes a non-Aborigine in a relationship to an Aborigine. An analysis of the props, technical details of the album and the image suggests a reconciliatory aspect that thwarts the predominant attitudes towards Aborigines in the area at that time.

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We investigate the claims of superiority of fundamental indexation strategy over capitalisation-weighted indexation by using data for Australian Securities Exchange (ASX) listed stocks. Whilst our results are in line with the outperformance observed in other geographical markets, we find that the excess returns from fundamental indexation in Australian market are much higher. On a rolling 5-year basis, the fundamental index always outperforms the capitalisation-weighted index. Our results suggest that superior performance of fundamental indexation could not be entirely attributed to value, size, or momentum effects. The outperformance persists even after adjusting for slightly higher transaction costs related to turnover.

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In this submission, we provide evidence for our view that copyright policy in the UK must encourage new digital business models which meet the changing needs of consumers and foster innovation in the UK both within, and beyond, the creative industries. We illustrate our arguments using evidence from the music industry. However, we believe that our key points on the relationship between the copyright system and innovative digital business models apply across the UK creative industries.

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Heteroatom doping on the edge of graphene may serve as an effective way to tune chemical activity of carbon-based electrodes with respect to charge carrier transfer in an aqueous environment. In a step towards developing mechanistic understanding of this phenomenon, we explore herein mechanisms of proton transfer from aqueous solution to pristine and doped graphene edges utilizing density functional theory. Atomic B-, N-, and O- doped edges as well as the native graphene are examined, displaying varying proton affinities and effective interaction ranges with the H3O+ charge carrier. Our study shows that the doped edges characterized by more dispersive orbitals, namely boron and nitrogen, demonstrate more energetically favourable charge carrier exchange compared with oxygen, which features more localized orbitals. Extended calculations are carried out to examine proton transfer from the hydronium ion in the presence of explicit water, with results indicating that the basic mechanistic features of the simpler model are unchanged.

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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.

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The Guide includes research findings from the Australian Centre for Philanthropy and Non Profit Studies at the Queensland University of Technology (QUT). This research probed the experiences of fourteen Indigenous people who have had different degrees of success in seeking funding from philanthropic organisations. This research shows how grantmakers can make a significant difference in the lives of Aboriginal and Torres Strait Islander people.

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Most security models for authenticated key exchange (AKE) do not explicitly model the associated certification system, which includes the certification authority (CA) and its behaviour. However, there are several well-known and realistic attacks on AKE protocols which exploit various forms of malicious key registration and which therefore lie outside the scope of these models. We provide the first systematic analysis of AKE security incorporating certification systems (ASICS). We define a family of security models that, in addition to allowing different sets of standard AKE adversary queries, also permit the adversary to register arbitrary bitstrings as keys. For this model family we prove generic results that enable the design and verification of protocols that achieve security even if some keys have been produced maliciously. Our approach is applicable to a wide range of models and protocols; as a concrete illustration of its power, we apply it to the CMQV protocol in the natural strengthening of the eCK model to the ASICS setting.

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Dedicated Short Range Communication (DSRC) is the emerging key technology supporting cooperative road safety systems within Intelligent Transportation Systems (ITS). The DSRC protocol stack includes a variety of standards such as IEEE 802.11p and SAE J2735. The effectiveness of the DSRC technology depends on not only the interoperable cooperation of these standards, but also on the interoperability of DSRC devices manufactured by various manufacturers. To address the second constraint, the SAE defines a message set dictionary under the J2735 standard for construction of device independent messages. This paper focuses on the deficiencies of the SAE J2735 standard being developed for deployment in Vehicular Ad-hoc Networks (VANET). In this regard, the paper discusses the way how a Basic Safety Message (BSM) as the fundamental message type defined in SAE J2735 is constructed, sent and received by safety communication platforms to provide a comprehensive device independent solution for Cooperative ITS (C-ITS). This provides some insight into the technical knowledge behind the construction and exchange of BSMs within VANET. A series of real-world DSRC data collection experiments was conducted. The results demonstrate that the reliability and throughput of DSRC highly depend on the applications utilizing the medium. Therefore, an active application-dependent medium control measure, using a novel message-dissemination frequency controller, is introduced. This application level message handler improves the reliability of both BSM transmissions/receptions and the Application layer error handling which is extremely vital to decentralized congestion control (DCC) mechanisms.

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Collisions among trains and cars at road/rail level crossings (LXs) can have severe consequences such as high level of fatalities, injuries and significant financial losses. As communication and positioning technologies have significantly advanced, implementing vehicular ad hoc networks (VANETs) in the vicinity of unmanned LXs, generally LXs without barriers, is seen as an efficient and effective approach to mitigate or even eliminate collisions without imposing huge infrastructure costs. VANETs necessitate unique communication strategies, in which routing protocols take a prominent part in their scalability and overall performance, through finding optimised routes quickly and with low bandwidth overheads. This article studies a novel geo-multicast framework that incorporates a set of models for communication, message flow and geo-determination of endangered vehicles with a reliable receiver-based geo-multicast protocol to support cooperative level crossings (CLXs), which provide collision warnings to the endangered motorists facing road/rail LXs without barriers. This framework is designed and studied as part of a $5.5 m Government and industry funded project, entitled 'Intelligent-Transport-Systems to improve safety at road/rail crossings'. Combined simulation and experimental studies of the proposed geo-multicast framework have demonstrated promising outcomes as cooperative awareness messages provide actionable critical information to endangered drivers who are identified by CLXs.

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This study was conducted within the context of a flexible education institution where conventional educational assessment practices and tests fail to recognise and assess the creativity and cultural capital of a cohort of marginalised young people. A new assessment model which included an electronic-portfolio-social-networking system (EPS) was developed and trialled to identify and exhibit evidence of students' learning. The study aimed to discern unique forms of cultural capital (Bourdieu, 1986) possessed by students who attend the Edmund Rice Education Australia Flexible Learning Centre Network (EREAFLCN). The EPS was trialled at the case study schools in an intervention and developed a space where students could make evident culturally specific forms of capital and funds of knowledge (Gonzalez, Moll, & Amanti, 2005). These resources were evaluated, modified and developed through dialogic processes utilising assessment for learning approaches (Qualifications and Curriculum Development Agency, 2009) in online and classroom settings. Students, peers and staff engaged in the recognition, judgement, revision and evaluation of students' cultural capital in a subfield of exchange (Bourdieu, 1990). The study developed the theory of assessment for learning as a field of exchange incorporating an online system as a teaching and assessment model. The term efield has been coined to describe this particular capital exchange model. A quasi-ethnographic approach was used to develop a collective case study (Stake, 1995). This case study involved an in-depth exploration of five students' forms of cultural capital and the ways in which this capital could be assessed and exchanged using the efield model. A comparative analysis of the five cases was conducted to identify the emergent issues of students' recognisable cultural capital resources and the processes of exchange that can be facilitated to acquire legitimate credentials for these students in the Australian field of education. The participants in the study were young people at two EREAFLC schools aged between 12 and 18 years. Data was collected through interviews, observations and examination of documents made available by the EREAFLCN. The data was coded and analysed using a theoretical framework based on Bourdieu's analytical tools and a sociocultural psychology theoretical perspective. Findings suggest that processes based on dialogic relationships can identify and recognise students' forms of cultural capital that are frequently misrecognised in mainstream school environments. The theory of assessment for learning as a field of exchange was developed into praxis and integrated in an intervention. The efield model was found to be an effective sociocultural tool in converting and exchanging students' capital resources for legitimated cultural and symbolic capital in the field of education.

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Previous research has shown that mobile phone use while driving can increase crash risk fourfold while texting results in 23 times greater crash risk for heavy vehicle drivers. However, mobile phone use has changed in recent years with the functional capabilities of smart phones to now also include a range of other common behaviours while driving such as using Facebook, emailing, the use of ‘apps’, and GPS. Research continues to show performance decrements for many such behaviours while driving, however many Australians still openly admit to illegal mobile phone use while driving despite ongoing enforcement efforts and public awareness campaigns. Of most concern are young drivers. ‘Apps’ available to restrict mobile phone use while in motion do not prevent use while a driver is stopped at traffic lights, so are therefore not a wholly viable solution. Vehicle manufacturers continue to develop in-vehicle technology to minimise distraction, however communication with the ‘outside world’ while driving is also perhaps a strong selling point for vehicles. Hence, the safety message that drivers should focus on the driving task solely and not use communication devices is unlikely to ever be internalised by many drivers. This paper reviews the available literature on the topic and argues that a better understanding of perceptions of mobile phone use while driving and motives for use are required to inform public awareness campaign development for specific road user groups. Additionally, illegal phone use while driving may be reinforced by not being apprehended (punishment avoidance), therefore stronger deterrence-focussed messages may also be beneficial.

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This paper presents a model for the generation of a MAC tag using a stream cipher. The input message is used indirectly to control segments of the keystream that form the MAC tag. Several recent proposals can be considered as instances of this general model, as they all perform message accumulation in this way. However, they use slightly different processes in the message preparation and finalisation phases. We examine the security of this model for different options and against different types of attack, and conclude that the indirect injection model can be used to generate MAC tags securely for certain combinations of options. Careful consideration is required at the design stage to avoid combinations of options that result in susceptibility to forgery attacks. Additionally, some implementations may be vulnerable to side-channel attacks if used in Authenticated Encryption (AE) algorithms. We give design recommendations to provide resistance to these attacks for proposals following this model.

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The most effective countermeasures to driver sleepiness (caffeine and a nap, ideally in combination) are not the most popular choice for UK drivers. Groups susceptible to driver sleepiness (OSA patients and truck drivers) do not favour effective countermeasures to driver sleepiness. Prior experience of driver sleepiness does not promote an effective choice of countermeasure.