971 resultados para Air Services Network
Resumo:
In this paper, a novel approach is developed to evaluate the overall performance of a local area network as well as to monitor some possible intrusion detections. The data is obtained via system utility 'ping' and huge data is analyzed via statistical methods. Finally, an overall performance index is defined and simulation experiments in three months proved the effectiveness of the proposed performance index. A software package is developed based on these ideas.
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Rural and remote community pharmacies service large areas of rural Queensland, and because of the distances involved often do not meet the patients for whom they provide medication. Telepharmacy would improve the quality of pharmaceutical services provided in rural and remote areas, by allowing community pharmacists to have realtime contact with dispensing doctors, aboriginal health workers and patients via a video-phone. We used commercial (analogue) videophones to connect community pharmacists to dispensing doctors, patients in depot pharmacies (i.e. those with no pharmacist) and aboriginal health workers. However, various problems occurred and only 10 video-phone interactions were recorded during the six-month project. In all of the recorded interactions, the video-phone was actually used as a conventional telephone because a video-connection could not be established at the time of the call. (This may have been due to telephone network problems in the rural areas.) Despite these problems, all project participants showed great enthusiasm for the potential benefits of such a service.
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Recent developments in service-oriented and distributed computing have created exciting opportunities for the integration of models in service chains to create the Model Web. This offers the potential for orchestrating web data and processing services, in complex chains; a flexible approach which exploits the increased access to products and tools, and the scalability offered by the Web. However, the uncertainty inherent in data and models must be quantified and communicated in an interoperable way, in order for its effects to be effectively assessed as errors propagate through complex automated model chains. We describe a proposed set of tools for handling, characterizing and communicating uncertainty in this context, and show how they can be used to 'uncertainty- enable' Web Services in a model chain. An example implementation is presented, which combines environmental and publicly-contributed data to produce estimates of sea-level air pressure, with estimates of uncertainty which incorporate the effects of model approximation as well as the uncertainty inherent in the observational and derived data.
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A city's branding is investigated using generic product and services branding models. Two generic branding models and tourism segmentation models guide an investigation into city branding 'as it should be' and 'as it is' using Birmingham, England as a case study. The unique characteristics of city brands are identified and Keller's Brand Report Card provides a theoretical framework for building a picture of the brand-building activity taking place in the city. Four themes emerge and are discussed: 1) the impact of a network on brand models developed for organisations; 2) segmentation of brand elements; 3) corporate branding; and 4) the political dimension. A conclusion is that city branding would be more effective if the systems and structures of generic branding models were adopted.
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The automatic interpolation of environmental monitoring network data such as air quality or radiation levels in real-time setting poses a number of practical and theoretical questions. Among the problems found are (i) dealing and communicating uncertainty of predictions, (ii) automatic (hyper)parameter estimation, (iii) monitoring network heterogeneity, (iv) dealing with outlying extremes, and (v) quality control. In this paper we discuss these issues, in light of the spatial interpolation comparison exercise held in 2004.
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In England, publicly supported advice to small firms is organized primarily through the Business Link (BL) network. Using the programme theory underlying this business support, we develop four propositions and test these empirically using data from a new survey of over 3000 English SMEs. We find strong support for the value to BL operators of a high profile to boost take-up. We find support for the BL’s market segmentation that targets intensive assistance to younger firms and those with limited liability. Allowing for sample selection, we find no significant effects on growth from ‘other’ assistance but find a significant employment boost from intensive assistance. This partially supports the programme theory assertion that BL improves business growth and strongly supports the proposition that there are differential outcomes from intensive and other assistance. This suggests an improvement in the BL network, compared with earlier studies, notably Roper et al. (2001), Roper and Hart (2005).
Resumo:
Third Generation cellular communication systems are expected to support mixed cell architecture in which picocells, microcells and macrocells are used to achieve full coverage and increase the spectral capacity. Supporting higher numbers of mobile terminals and the use of smaller cells will result in an increase in the number of handovers, and consequently an increase in the time delays required to perform these handovers. Higher time delays will generate call interruptions and forced terminations, particularly for time sensitive applications like real-time multimedia and data services. Currently in the Global System for Mobile communications (GSM), the handover procedure is initiated and performed by the fixed part of the Public Land Mobile Network (PLMN). The mobile terminal is only capable of detecting candidate base stations suitable for the handover; it is the role of the network to interrogate a candidate base station for a free channel. Handover signalling is exchanged via the fixed network and the time delay required to perform the handover is greatly affected by the levels of teletraffic handled by the network. In this thesis, a new handover strategy is developed to reduce the total time delay for handovers in a microcellular system. The handover signalling is diverted from the fixed network to the air interface to prevent extra delays due to teletraffic congestion, and to allow the mobile terminal to exchange signalling directly with the candidate base station. The new strategy utilises Packet Reservation Multiple Access (PRMA) technique as a mechanism to transfer the control of the handover procedure from the fixed network to the mobile terminal. Simulation results are presented to show a dramatic reduction in the handover delay as compared to those obtained using fixed channel allocation and dynamic channel allocation schemes.
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Concern has been expressed in the professional literature - borne out by professional experience and observation - that the supply and demand relationship existing between the 13 English and Welsh Library and Information Studies (LIS) Schools (as providers of `First Professional' staff) and the Higher Education Library and Information Services (HE LIS) sector of England and Wales (as one group of employers of such staff) is unsatisfactory and needs attention. An appropriate methodology to investigate this problem was devised. A basic content analysis of Schools' curricular and recruitment material intended for public consumption was undertaken to establish an overview of the LIS initial professional education system in England and Wales, and to identify and analyse any covert messages imparted to readers. This was followed by a mix of Main Questionnaires and Semi-Structured Interviews with appropriate populations. The investigation revealed some serious areas of dissatisfaction by the HE LIS Chiefs with the role and function of the Schools. Considerable divergence of views emerged on the state of the working relationships between the two sectors and on the Schools' successes in meeting the needs of the HE LIS sector and on CPD provision. There were, however, areas of substantial and consistent agreement between the two sectors. The main implications of the findings were that those areas encompassing divergence of views were worrying and needed addressing by both sides. Possible ways forward included recommendations on improving the image of the profession purveyed by the Schools; the forming of closer and more effective inter-sectoral relationships; recognising fully the importance of `practicum' and increasing and sustaining the network of `practicum' providers.
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Quality of services (QoS) support is critical for dedicated short range communications (DSRC) vehicle networks based collaborative road safety applications. In this paper we propose an adaptive power and message rate control method for DSRC vehicle networks at road intersections. The design objective is to provide high availability and low latency channels for high priority emergency safety applications while maximizing channel utilization for low priority routine safety applications. In this method an offline simulation based approach is used to find out the best possible configurations of transmit power and message rate for given numbers of vehicles in the network. The identified best configurations are then used online by roadside access points (AP) according to estimated number of vehicles. Simulation results show that this adaptive method significantly outperforms a fixed control method. © 2011 Springer-Verlag.
Resumo:
Various flexible mechanisms related to quality of service (QoS) provisioning have been specified for uplink traffic at the medium access control (MAC) layer in the IEEE 802.16 standards. Among the mechanisms, contention based bandwidth request scheme can be used to indicate bandwidth demands to the base station for the non-real-time polling and best-effort services. These two services are used for most applications with unknown traffic characteristics. Due to the diverse QoS requirements of those applications, service differentiation (SD) is anticipated over the contention based bandwidth request scheme. In this paper we investigate the SD with the bandwidth request scheme by means of assigning different channel access parameters and bandwidth allocation priorities at different packets arrival probability. The effectiveness of the differentiation schemes is evaluated by simulations. It is observed that the initial backoff window can be efficient in SD, and if combined with the bandwidth allocation priority, the SD performances will be better.
Resumo:
This paper starts from the viewpoint that enterprise risk management is a specific application of knowledge in order to control deviations from strategic objectives, shareholders’ values and stakeholders’ relationships. This study is looking for insights into how the application of knowledge management processes can improve the implementation of enterprise risk management. This article presents the preliminary results of a survey on this topic carried out in the financial services sector, extending a previous pilot study that was in retail banking only. Five hypotheses about the relationship of knowledge management variables to the perceived value of ERM implementation were considered. The survey results show that the two people-related variables, perceived quality of communication among groups and perceived quality of knowledge sharing were positively associated with the perceived value of ERM implementation. However, the results did not support a positive association for the three variables more related to technology, namely network capacity for connecting people (which was marginally significant), risk management information system functionality and perceived integration of the information systems. Perceived quality of communication among groups appeared to be clearly the most significant of these five factors in affecting the perceived value of ERM implementation.