72 resultados para cache coherence protocols

em Deakin Research Online - Australia


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This study investigated the physical and psychological impact of arthritis on people's quality of life. A range of variables were examined in a sample of 375 participants who comprised three groups: people with arthritis receiving a support-based service from the Arthritis Foundation of Victoria, people with arthritis receiving standard treatment, and a group of people from the general population. The results revealed that the two arthritis groups reported a significantly higher level of functional impairment, pain, and negative affectivity, and lowered mood, positive affect, and Sense of Coherence, compared to the general population group. They also reported normal levels of importance, but lower levels of satisfaction on various life domains. After statistically controlling for pain however, group differences were eliminated on all variables except for functional impairment and for all satisfaction domains except health. These data are interpreted as evidence that the combination of low domain satisfaction coupled with high domain importance yields a negative psychological state. This, then suggests the possibility of a therapy based on reducing the perceived importance of health.

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The purpose of this study was to quantify the strength of motor-unit coherence from the first dorsal interosseus muscle in young and old adults using data obtained in a previous study, where no differences in motor-unit synchronization between the two groups were observed.

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The purpose of the study was to quantify the strength of motor-unit coherence from the left and right first dorsal interosseous muscles in untrained, skill-trained (musicians), and strength-trained (weightlifters) individuals who had long-term specialized use of their hand muscles. The strength of motor-unit coherence was quantified from a total of 394 motor-unit pairs in 13 subjects using data from a previous study in which differences were found in the strength of motor-unit synchronization depending on training status. In the present study, we found that the strength of motor-unit coherence was significantly greater in the left compared with the right hand of untrained right-handed subjects with the largest differences observed between 21 and 24 Hz. The strength of motor-unit coherence was lower in both hands of skill-trained subjects (21–27 Hz) and the right (skilled) hand of untrained subjects (21–24 Hz), whereas the largest motor-unit coherence was observed in both hands of strength-trained subjects (3–9 and 21–27 Hz). A strong curvilinear association was observed between motor-unit synchronization and the integral of coherence at 10–30 Hz in all motor-unit pairs (r2 = 0.77), and was most pronounced in strength-trained subjects (r2 = 0.90). Furthermore, this association was accentuated when using synchronization data with broad peaks (>11 ms), suggesting that the 10- to 30-Hz coherence is due to oscillatory activity in indirect branched common inputs. The altered coherence with training may be due to an interaction between cortical inhibition and the number of direct common inputs to motor neurons in skill- or strength-trained hands.

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Anycast and multicast are two important Internet services. Combining the two protocols can provide new and practical services. In this paper we propose a new Internet service, Minicast: in the scenario of n replicated or similar servers, deliver a message to at least m members, 1 m n. Such a service has potential applications in information retrieval, parallel computing, cache queries, etc. The service can provide the same Internet service with an optimal cost, reducing bandwidth consumption, network delay, and so on. We design a multi-core tree based architecture for the Minicast service and present the criteria for calculating the subcores among a subset of Minicast members. Simulation shows that the proposed architecture can even the Minicast traffic, and the Minicast application can save the consumptions of network resource.

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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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Histograms have been used for Shape Representation and Retrieval. The drawback of the histograms method is that histograms can be same for dissimilar shapes, which renders the method less effective for retrieval of shapes. In this paper, we describe the concept of coherence. We show how coherence can be used with distance and angular histograms. We perform experiments to test the effectiveness of the proposed method. It is found that coherence improves accuracy of retrieval significantly.

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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.