981 resultados para Powerline Communications, Onde convogliate, HomePlug Powerline Alliance, IEEE1901, OFDM, Spread Spectrum, CENELEC EN50065-1
Resumo:
The recent advances in wireless communication techniques have made it possible for fast-moving vehicles to download data from the roadside communications infrastructure [e.g., IEEE 802.11b Access Point (AP)], namely, Drive-thru Internet. However, due to the high mobility, harsh, and intermittent wireless channels, the data download volume of individual vehicle per drive-thru is quite limited, as observed in real-world tests. This would severely restrict the service quality of upper layer applications, such as file download and video streaming. On addressing this issue, in this paper, we propose ChainCluster, a cooperative Drive-thru Internet scheme. ChainCluster selects appropriate vehicles to form a linear cluster on the highway. The cluster members then cooperatively download the same content file, with each member retrieving one portion of the file, from the roadside infrastructure. With cluster members consecutively driving through the roadside infrastructure, the download of a single vehicle is virtually extended to that of a tandem of vehicles, which accordingly enhances the probability of successful file download significantly. With a delicate linear cluster formation scheme proposed and applied, in this paper, we first develop an analytical framework to evaluate the data volume that can be downloaded using cooperative drive-thru. Using simulations, we then verify the performance of ChainCluster and show that our analysis can match the simulations well. Finally, we show that ChainCluster can outperform the typical studied clustering schemes and provide general guidance for cooperative content distribution in highway vehicular communications.
Resumo:
This article draws on data from a three-year Australian Research Council-funded study that examined the ways in which young children become numerate in the twenty-first century. We were interested in the authentic problem-solving contexts that we believe are required to create meaningful learning. This being so, our basic tenet was that such experiences should involve the use of information and communications technologies (ICT) where relevant, but not in tokenistic ways. This article highlights learning conditions in which young children can become numerate in contemporary times. We consider ‘academic’ or ‘school-based’ mathematical tasks in the context of a Mathematical Tasks Continuum. This continuum was conceptualised to enable focused and detailed thinking about the scope and range of mathematical tasks that young children are able to engage within contemporary school contexts. The data from this study show that most of the tasks the children experienced in early years mathematics classes were unidimensional in their make up. That is, they focus on the acquisition of specific skills and then they are practiced in disembedded contexts. We suggest that the framework created in the form of the Mathematical Tasks Continuum can facilitate teachers thinking about the possible ways in which they could extend children’s academic work in primary school mathematics, so that the process of becoming numerate becomes more easily related to authentic activities that they are likely to experience in everyday life.
Resumo:
The treatment alliance is the arena in which psychopharmacological and other therapeutic interventions occur. The nature and quality of the treatment alliance may affect adherence to treatment and the realization of the benefits of effective pharmacological treatment in clinical practice. It is an area that has attracted little systematic study, despite the available evidence suggesting that it plays a measurable role in clinical outcomes.
Resumo:
Many services and applications in vehicular ad-hoc networks (VANETs) require preserving and secure data communications. To improve driving safety and comfort, the traffic-related status information will be broadcasted regularly and shared among drivers. Without the security and privacy guarantees, attackers could track their interested vehicles by collecting and analyzing their traffic messages. Hence, anonymous message authentication is an essential requirement of VANETs. On the other hand, when a vehicle is involved in a dispute event of warning message, the certificate authority should be able to recover the real identity of this vehicle. To deal with this issue, we propose a new privacy-preserving authentication protocol with authority traceability using elliptic curve based chameleon hashing. Compared with existing schemes, our approach possesses the following features: 1) mutual and anonymous authentication for both vehicle-to-vehicle and vehicle-to-roadside communications, 2) vehicle unlinkability, 3) authority tracking capability, and 4) high computational efficiency. We also demonstrate the merits of our proposed scheme through security analysis and extensive performance evaluation.
Resumo:
In large-scale systems, user authentication usually needs the assistance from a remote central authentication server via networks. The authentication service however could be slow or unavailable due to natural disasters or various cyber attacks on communication channels. This has raised serious concerns in systems which need robust authentication in emergency situations. The contribution of this paper is two-fold. In a slow connection situation, we present a secure generic multi-factor authentication protocol to speed up the whole authentication process. Compared with another generic protocol in the literature, the new proposal provides the same function with significant improvements in computation and communication. Another authentication mechanism, which we name stand-alone authentication, can authenticate users when the connection to the central server is down. We investigate several issues in stand-alone authentication and show how to add it on multi-factor authentication protocols in an efficient and generic way.
Resumo:
Purpose – The aim of this paper is to report on an exploratory, qualitative study of how small and medium enterprises (SMEs) describe their firm’s relationships with or impact on stakeholders when communicating corporate social responsibility (CSR) on their websites. Design/methodology/approach – Qualitative content analysis was conducted on 22 Australian SME websites from the information media and telecommunications sector. Stakeholder theory was used as the basis for analysis. Findings – An important aspect of CSR communication is reporting the firm’s relationships with stakeholders such as society/communities, ecological environment, employees, customers and suppliers. This paper provides insights into how these relationships are manifested in SME website communications. For example, three-way relationships between the firm and stakeholders were described on some websites, but few explained the impact of their CSR on stakeholders. Research limitations/implications – This study concentrated on identifying the CSR communication on websites from one industry sector in Australia. These limitations provide the basis for future research to explore and compare CSR communication on websites by SMEs from other industry sectors and countries. Practical implications – The findings offer SME owner-managers ideas on different ways they can incorporate details of stakeholder relationships in CSR website communications. Originality/value – There has been little research on how SMEs use channels such as websites to communicate CSR. This paper addresses this gap in knowledge by providing insights into how SMEs describe stakeholder relationships in CSR website communications.
Resumo:
Therapists in offending behaviour programs use a range of strategies to develop the therapeutic alliance to promote treatment collaboration. They described significant difficulties, however, in responding to personality dysfunction. Analysis of treatment sessions revealed therapists often attempted to engage clients but did not often use ruptures in the alliance as therapeutic opportunities or attend to withdrawn clients. Recommendations are made to better support correctional therapists utilise the alliance to maximise treatment
Resumo:
© 2015 Taylor & Francis The article provides a conceptual contribution by developing a framework for business-to-business (B2B) marketers seeking to implement online communities (OLCs). Furthermore, the conceptual contribution is augmented by a small-scale exploratory study comprising in-depth interviews with B2B chief marketing officers (CMOs). The findings challenge existing thinking that B2B marketers can follow generic marketing communication frameworks. This is due to the differences in B2B OLCs in terms of multiple stakeholders and two-way information flows and differences in buyer behaviour. For researchers, the contribution is an embryonic model that will facilitate future conceptual development as well as empirical testing through a series of research propositions. A sequential decision-making framework, which identifies key implementation challenges, is provided for B2B managers.
Resumo:
Feedback has long been considered a vital component of training in the health professions. Nonetheless, it remains difficult to enact the feedback process effectively. In part, this may be because, historically, feedback has been framed in the medical education literature as a unidirectional content-delivery process with a focus on ensuring the learner's acceptance of the content. Thus, proposed solutions have been organized around mechanistic, educator-driven, and behavior-based best practices. Recently, some authors have begun to highlight the role of context and relationship in the feedback process, but no theoretical frameworks have yet been suggested for understanding or exploring this relational construction of feedback in medical education. The psychotherapeutic concept of the "therapeutic alliance" may be valuable in this regard.In this article, the authors propose that by reorganizing constructions of feedback around an "educational alliance" framework, medical educators may be able to develop a more meaningful understanding of the context-and, in particular, the relationship-in which feedback functions. Use of this framework may also help to reorient discussions of the feedback process from effective delivery and acceptance to negotiation in the environment of a supportive educational relationship.To explore and elaborate these issues and ideas, the authors review the medical education literature to excavate historical and evolving constructions of feedback in the field, review the origins of the therapeutic alliance and its demonstrated utility for psychotherapy practice, and consider implications regarding learners' perceptions of the supervisory relationship as a significant influence on feedback acceptance in medical education settings.
Resumo:
The Belgrade Regional Conservation Alliance is an organization that is dedicated to preserving land and water quality in the Belgrade Lakes region in Maine. The BRCA holds land in such towns as Belgrade, Mount Vernon, New Sharon, Vienna, Rome, Smithfield, and Oakland. The BRCA is looking to expand its acreage in and around these areas to better accommodate the public and to promote the ongoing effort to conserve land as part of the Kennebec Highlands Project. The BRCA is currently considering parcels of 50+ acres in New Sharon, Rome, Belgrade, and Mount Vernon. In order to identify possible suitable parcels, we completed a GIS analysis and produced these layered maps, which highlight areas of land that we think might be desirable to the BRCA. Our analysis encompasses human access, wildlife access, and the locations and sizes of parcels.
Resumo:
The Belgrade Regional Conservation Alliance (BRCA) has acquired a great deal of land in the Belgrade Lakes region of Maine and is currently in negotiations on many pieces of land throughout the area. Data available online from the Maine Office of GIS, and data from the BRCA were used to carry out this analysis. One area of interest is Mount Phillip, the summit of which the BRCA recently acquired. There is a good view to the south of the mountain, but the potential view to the east and north is in question. This study analyzed the view from the top of the mountain, focusing on two landmarks: Mosher Hill to the east, and North Pond to the north. The analysis shows that both Mosher Hill and North Pond can be seen well from Mount Phillip. These results could help the BRCA both by adding weight to their negotiations to protect Mosher Hill, as well as influencing their decision whether or not to thin part of the forest on Mount Phillip to open up the view of North Pond that is currently blocked.
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o Estado de Direito é considerado uma conquista da sociedade moderna. Hoje, porém, numa sociedade multifacetada, com questionamentos profundos não somente sobre a atuação do Estado em si, mas especialmente sobre suas características frente a este novo panorama social, surgem indagações sobre a adequação deste Estado de Direito aos novos tempos e, ainda mais, seu possível novo papel na atualidade, especialmente em sua abordagem Democrática;
Resumo:
Dissertação apresentada ao Programa de Pós-graduação em Administração da Universidade Municipal de São Caetano do Sul para a obtenção do título de Mestre em Administração