43 resultados para TDMA protocols

em Deakin Research Online - Australia


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Current studies to analyzing security protocols using formal methods require users to predefine authentication goals. Besides, they are unable to discover potential correlations between secure messages. This research attempts to analyze security protocols using data mining. This is done by extending the idea of association rule mining and converting the verification of protocols into computing the frequency and confidence of inconsistent secure messages. It provides a novel and efficient way to analyze security protocols and find out potential correlations between secure messages. The conducted experiments demonstrate our approaches.

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Security protocols have been widely used to safeguard secure electronic transactions. We usually assume that principals are credible and shall not maliciously disclose their individual secrets to someone else. Nevertheless, it is impractical to completely ignore the possibility that some principals may collude in private to achieve a fraudulent or illegal purpose. Therefore, it is critical to address the possibility of collusion attacks in order to correctly analyse security protocols. This paper proposes a framework by which to detect collusion attacks in security protocols. The possibility of security threats from insiders is especially taken into account. The case study demonstrates that our methods are useful and promising in discovering and preventing collusion attacks.

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Most of the current web-based application systems suffer from poor performance and costly heterogeneous accessing. Distributed or replicated strategies can alleviate the problem in some degree, but there are still some problems of the distributed or replicated model, such as data synchronization, load balance, and so on.  In this paper, we propose a novel architecture for Internet-based data processing system based on multicast and anycast protocols. The proposed architecture breaks the functionalities of existing data processing system, in particular, the database functionality, into several agents. These agents communicate with each other using multicast and anycast mechanisms. We show that the proposed architecture provides better scalability, robustness, automatic load balance, and performance than the current distributed architecture of Internet-based data
processing.

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The cost of recovery protocols is important with respect to system performance during normal operation and failure in terms of overhead, and time taken to recover failed transactions. The cost of recovery protocols for web database systems has not been addressed much. In this paper, we present a quantitative study of cost of recovery protocols. For this purpose, we use an experiment setup to evaluate the performance of two recovery algorithms, namely the, two-phase commit algorithm and log-based algorithm. Our work is a step towards building reliable protocols for web database systems.

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Mobile ad-hoc networks are characterised by constant topology changes, the absence of fixed infrastructure and lack of any centralised control. Traditional routing algorithms prove to be inefficient in such a changing environment. Ad-hoc routing protocols such as dynamic source routing (DSR), ad-hoc on-demand distance vector routing (AODV) and destination-sequence distance vector (DSDV) have been proposed to solve the multi hop routing problem in ad-hoc networks. Performance studies of these routing protocols have assumed constant bit rate (CBR) traffic. Real-time multimedia traffic generated by video-on demand and teleconferencing services are mostly variable bit rate (VBR) traffic. Most of these multimedia traffic is encoded using the MPEG standard. (ISO moving picture expert group). When video traffic is transferred over MANETs a series of performance issues arise. In this paper we present a performance comparison of three ad-hoc routing protocols - DSR, AODV and DSDV when streaming MPEG4 traffic. Simulation studies show that DSDV performs better than AODV and DSR. However all three protocols fail to provide good performance in large, highly mobile network environments. Further study is required to improve the performance of these protocols in mobile ad-hoc networks offering VBR services.

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Traditional approaches such as theorem proving and model checking have been successfully used to analyze security protocols. Ideally, they assume the data communication is reliable and require the user to predetermine authentication goals. However, missing and inconsistent data have been greatly ignored, and the increasingly complicated security protocol makes it difficult to predefine such goals. This paper presents a novel approach to analyze security protocols using association rule mining. It is able to not only validate the reliability of transactions but also discover potential correlations between secure messages. The algorithm and experiment demonstrate that our approaches are useful and promising.

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Aims and objectives. The aim of the study was to determine how graduate nurses use protocols in their medication management activities. The objectives were to: examine the extent of adherence to various protocols in relation to medication activities and determine how the ward environment impacts on graduate nurses' use of protocols to manage patients' medications.
Background. Protocols help newly qualified nurses integrate new knowledge into practice and promote effective decision-making
Design. A descriptive prospective qualitative design was used.
Methods. Twelve graduate nurses involved in direct patient care in medical, surgical and specialty wards of a metropolitan teaching hospital participated in the study. Participant observations were conducted with the graduate nurses during a two-hour period when medications were being administered to patients. In-depth interviews were conducted with each nurse immediately after observations and demographic data were collected on participating nurses and patients in their care, including all medications prescribed. Protocols associated with medication management activities for the clinical settings were also transcribed.
Results. Six themes were evident from the data: availability and use of protocols, scrutinizing patients' identity before medication administration, double-checking certain medications before administration, writing incident reports, following specific policies and timing the administration of medications.
Conclusion. Graduate nurses adhered to protocols if they were perceived not to impede with other nursing activities. Participants were also more likely to follow protocols if they felt encouraged to make their own decisions and if there was a decreased likelihood that disciplinary action would be involved.
Relevance to clinical practice. Experienced health professionals should encourage graduate nurses to comply with medication protocols and to make clinically reasoned decisions about medication activities. By providing peer support and acting as role models, experienced health professionals can also demonstrate to graduate nurses how effective protocol use is an important component of quality patient care.

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The aim of this manual is to provide a comprehensive practical tool for the generation and analysis of genetic data for subsequent application in aquatic resources management in relation to genetic stock identification in inland fisheries and aquaculture. The material only covers general background on genetics in relation to aquaculture and fisheries resource management, the techniques and relevant methods of data analysis that are commonly used to address questions relating to genetic resource characterisation and population genetic analyses. No attempt is made to include applications of genetic improvement techniques e.g. selective breeding or producing genetically modified organisms (GMOs). The manual includes two ‘stand-alone’ parts, of which this is the second volume: Part 1 – Conceptual basis of population genetic approaches: will provide a basic foundation on genetics in general, and concepts of population genetics. Issues on the choices of molecular markers and project design are also discussed. Part 2 – Laboratory protocols, data management and analysis: will provide step-by-step protocols of the most commonly used molecular genetic techniques utilised in population genetics and systematic studies. In addition, a brief discussion and explanation of how these data are managed and analysed is also included. This manual is expected to enable NACA member country personnel to be trained to undertake molecular genetic studies in their own institutions, and as such is aimed at middle and higher level technical grades. The manual can also provide useful teaching material for specialised advanced level university courses in the region and postgraduate students. The manual has gone through two development/improvement stages. The initial material was tested at a regional workshop and at the second stage feedback from participants was used to improve the contents.

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Aim: The aim of this review was to determine if ventilation-weaning protocols developed and implemented by multidisciplinary teams (MDTs) reduced the duration of mechanical ventilation in adult intensive care patients compared to usual care.

Method: A systematic review was conducted to review published research studies from January 1999 to June 2009 to identify and analyse the best available evidence on MDT-based weaning protocols in adult intensive care patients. All relevant studies based on electronic searches of MEDLINE, EMBASE, CINAHL, the Cochrane Controlled Trials Registry and the Cochrane Database of Systematic Reviews were included. Where possible data were pooled and a meta-analysis performed. A narrative synthesis of data was conducted to provide a critical appraisal of nonrandomised controlled trials included in the review.

Results: Three pre- and postinterventional studies were identified for inclusion in this review. Results show equivocal support for weaning protocols developed and implemented by MDTs for reducing duration of mechanical ventilation.

Conclusion: Communication and organizational processes must be addressed for multidisciplinary protocols to be effective. Due to methodological limitations of included studies, large randomised controlled trials are required to provide high-level evidence of the effects of MDT-based protocols on duration of mechanical ventilation.

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Recent research has shown that the single-user security of optimistic fair exchange cannot guarantee the multi-user security. This paper investigates the conditions under which the security of optimistic fair exchange in the single-user setting is preserved in the multi-user setting. We first introduce and define a property called “Strong Resolution-Ambiguity”. Then we prove that in the certified-key model, an optimistic fair exchange protocol is secure in the multi-user setting if it is secure in the single-user setting and has the property of strong resolution-ambiguity. Finally we provide a new construction of optimistic fair exchange with strong resolution-ambiguity. The new protocol is setup-free, stand-alone and multi-user secure without random oracles.

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Mobile agents are expected to run in partially unknown and untrustworthy environments. They transport from one host to another host through insecure channels and may execute on non-trusted hosts. Thus, they are vulnerable to direct security attacks of intruders and non-trusted hosts. The security of information the agents collect is a fundamental requirement for a trusted implementation of electronic business applications and trade negotiations. This chapter discusses the security protocols presented in the literature that aim to secure the data mobile agents gather while searching the Internet, and identifies the security flaws revealed in the protocols. The protocols are analyzed with respect to the security properties, and the security flaws are identified. Two recent promising protocols that fulfill the various security properties are described. The chapter also introduces common notations used in describing security protocols and describes the security properties of the data that mobile agents gather.