902 resultados para Specialized content knowledge


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Information-centric networking (ICN) enables communication in isolated islands, where fixed infrastructure is not available, but also supports seamless communication if the infrastructure is up and running again. In disaster scenarios, when a fixed infrastructure is broken, content discovery algorit hms are required to learn what content is locally available. For example, if preferred content is not available, users may also be satisfied with second best options. In this paper, we describe a new content discovery algorithm and compare it to existing Depth-first and Breadth-first traversal algorithms. Evaluations in mobile scenarios with up to 100 nodes show that it results in better performance, i.e., faster discovery time and smaller traffic overhead, than existing algorithms.

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In this work, we propose a novel network coding enabled NDN architecture for the delivery of scalable video. Our scheme utilizes network coding in order to address the problem that arises in the original NDN protocol, where optimal use of the bandwidth and caching resources necessitates the coordination of the forwarding decisions. To optimize the performance of the proposed network coding based NDN protocol and render it appropriate for transmission of scalable video, we devise a novel rate allocation algorithm that decides on the optimal rates of Interest messages sent by clients and intermediate nodes. This algorithm guarantees that the achieved flow of Data objects will maximize the average quality of the video delivered to the client population. To support the handling of Interest messages and Data objects when intermediate nodes perform network coding, we modify the standard NDN protocol and introduce the use of Bloom filters, which store efficiently additional information about the Interest messages and Data objects. The proposed architecture is evaluated for transmission of scalable video over PlanetLab topologies. The evaluation shows that the proposed scheme performs very close to the optimal performance

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Content-Centric Networking (CCN) naturally supports multi-path communication, as it allows the simultaneous use of multiple interfaces (e.g. LTE and WiFi). When multiple sources and multiple clients are considered, the optimal set of distribution trees should be determined in order to optimally use all the available interfaces. This is not a trivial task, as it is a computationally intense procedure that should be done centrally. The need for central coordination can be removed by employing network coding, which also offers improved resiliency to errors and large throughput gains. In this paper, we propose NetCodCCN, a protocol for integrating network coding in CCN. In comparison to previous works proposing to enable network coding in CCN, NetCodCCN permit Interest aggregation and Interest pipelining, which reduce the data retrieval times. The experimental evaluation shows that the proposed protocol leads to significant improvements in terms of content retrieval delay compared to the original CCN. Our results demonstrate that the use of network coding adds robustness to losses and permits to exploit more efficiently the available network resources. The performance gains are verified for content retrieval in various network scenarios.

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The increasing interest in autonomous coordinated driving and in proactive safety services, exploiting the wealth of sensing and computing resources which are gradually permeating the urban and vehicular environments, is making provisioning of high levels of QoS in vehicular networks an urgent issue. At the same time, the spreading model of a smart car, with a wealth of infotainment applications, calls for architectures for vehicular communications capable of supporting traffic with a diverse set of performance requirements. So far efforts focused on enabling a single specific QoS level. But the issues of how to support traffic with tight QoS requirements (no packet loss, and delays inferior to 1ms), and of designing a system capable at the same time of efficiently sustaining such traffic together with traffic from infotainment applications, are still open. In this paper we present the approach taken by the CONTACT project to tackle these issues. The goal of the project is to investigate how a VANET architecture, which integrates content-centric networking, software-defined networking, and context aware floating content schemes, can properly support the very diverse set of applications and services currently envisioned for the vehicular environment.

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Specification consortia and standardization bodies concentrate on e-Learning objects to en-sure reusability of content. Learning objects may be collected in a library and used for deriv-ing course offerings that are customized to the needs of different learning communities. How-ever, customization of courses is possible only if the logical dependencies between the learn-ing objects are known. Metadata for describing object relationships have been proposed in several e-Learning specifications. This paper discusses the customization potential of e-Learning objects but also the pitfalls that exist if content is customized inappropriately.

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The shift from host-centric to information-centric networking (ICN) promises seamless communication in mobile networks. However, most existing works either consider well-connected networks with high node density or introduce modifications to {ICN} message processing for delay-tolerant Networking (DTN). In this work, we present agent-based content retrieval, which provides information-centric {DTN} support as an application module without modifications to {ICN} message processing. This enables flexible interoperability in changing environments. If no content source can be found via wireless multi-hop routing, requesters may exploit the mobility of neighbor nodes (called agents) by delegating content retrieval to them. Agents that receive a delegation and move closer to content sources can retrieve data and return it back to requesters. We show that agent-based content retrieval may be even more efficient in scenarios where multi-hop communication is possible. Furthermore, we show that broadcast communication may not be necessarily the best option since dynamic unicast requests have little overhead and can better exploit short contact times between nodes (no broadcast delays required for duplicate suppression).

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Study purpose. Genetic advances are significantly impacting healthcare, yet recent studies of ethnic group participation in genetic services demonstrate low utilization rates by Latinos. Limited genetic knowledge is a major barrier. The purpose of this study was to field test items in a Spanish-language instrument that will be used to measure genetic knowledge relevant to type 2 diabetes among members of the ethnically heterogeneous U.S. Latino community. Accurate genetic knowledge measurement can provide the foundation for interventions to enhance genetic service utilization. ^ Design. Three waves of cognitive interviews were conducted in Spanish to field test 44 instrument items Thirty-six Latinos, with 12 persons representative of Mexican, Central and South American, and Cuban heritage participated, including 7 males and 29 females between 22 and 60 years of age; 17 participants had 12 years or less of education. ^ Methods. Text narratives from transcriptions of audiotaped interviews were qualitatively analyzed using a coding strategy to indicate potential sources of response error. Through an iterative process of instrument refinement, codes that emerged from the data were used to guide item revisions at the conclusion of each phase; revised items were examined in subsequent interview waves. ^ Results. Inter-cultural and cross-cultural themes associated with difficulties in interpretation and grammatical structuring of items were identified; difficulties associated with comprehension reflected variations in educational level. Of the original 44 items, 32 were retained, 89% of which were revised. Six additional items reflective of cultural knowledge were constructed, resulting in a 38-item instrument. ^ Conclusions. Use of cognitive interviewing provided a valuable tool for detecting both potential sources of response error and cultural variations in these sources. Analysis of interview data guided successive instrument revisions leading to improved item interpretability and comprehension. Although testing in a larger sample will be essential to test validity and reliability, the outcome of field testing suggests initial content validity of a Spanish-language instrument to measure genetic knowledge relative to type 2 diabetes. ^ Keywords. Latinos, genetic knowledge, instrument development, cognitive interviewing ^

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We formed an academic-community partnership with the Salsa Caliente program to undertake a project to better understand how Latina women with cardiovascular disease (CVD) or at risk of CVD view and understand CVD. This study's research question examines the sociocultural factors that influence and inform Latino women's perceptions and beliefs about CVD. Seven out the eleven participants in the Salsa Caliente program consented to be interviewed. The data was collected through recorded interviews, which were transcribed and then analyzed for common themes found among all the participants' narratives. The content analysis looking into common themes yielded four: 1) increased awareness of CVD, 2) trust in doctor, 3) delay in doctor visits, and 4) awareness of health. Implications for interventions and further research are discussed.^

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Hemophilia is a hereditary bleeding disorder which requires lifelong specialized care. A network of Hemophilia Treatment Centers (HTCs) exists to meet the medical needs of patients affected by hemophilia. Genetic counseling services are an integral part of the HTC model of care; however, many HTCs do not have genetic counselors on staff. As a result, the duty to provide these services must fall to other healthcare providers within the HTC. To assess the knowledge and attitudes of these providers we developed a 49 question survey that was distributed electronically to hematologists and nurses at U.S. HTCs. The survey consisted of a three sections: demographic information, knowledge of hemophilia genetics, and attitudes towards genetic services. A total of 111 complete responses were received and analyzed. The average knowledge score among all participants was 74.8% with a total of 81 participants receiving a passing score of 70% or above. Thirty participants scored below 70% in the knowledge section. In general, attitude scores were high indicating that the majority of hematologists and nurses in HTCs feel confident in their ability to provide genetic counseling services. Over 90% of participants reported that they have some form of access to genetic counseling services at their center. Hematologists and nurses practicing in U.S. HTCs demonstrate sufficient knowledge of the genetics of hemophilia, and they generally feel confident in their ability to provide genetic counseling services to their patients. While their knowledge is sufficient, the average knowledge score was lower than 75%. Certain questions covering new genetic technologies and testing practices were more commonly missed than questions asking about more basic aspects of hemophilia genetics, such as inheritance and carrier testing. Finally, many clinics report having access to a counselor, but it is oftentimes a hematologist or nurse who is providing genetic counseling services to patients. Given the inconsistency in knowledge among providers coupled with the high confidence in one’s ability to counsel patients, it leaves room to question whether information about the genetics of hemophilia is being communicated to patients in the most appropriate and accurate manner.

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The limited knowledge and/or the inability to control physiological condition parameters that influence the fate of organohalogen contaminants (OHCs) has been the foremost confounding aspect in monitoring programs and health risk assessments of wild top predators in the Arctic such as the polar bear (Ursus maritimus). In the present comparative study, we used a potential surrogate Canoidea species for the East Greenland polar bear, the captive sledge dog (Canis familiaris), to investigate some factors that may influence the bioaccumulation and biotransformation of major chlorinated and brominated OHCs in adipose tissue and blood (plasma) of control (fed commercial pork fat) and exposed (fed West Greenland minke whale (Balaenoptera acutorostrata) blubber) adult female sledge dogs. Furthermore, we compared the patterns and concentrations of OHCs and their known or suggested hydroxylated (OH) metabolites (e.g., OH-PCBs) in sledge dogs with those in adipose tissue and blood (plasma) of East Greenland adult female polar bears, and blubber of their main prey species, the ringed seal (Pusa hispida). The two-year feeding regime conducted with sledge dogs led to marked differences in overall adipose tissue (and plasma) OHC residue accumulation between the control and exposed groups. Characteristic prey-to-predator OHC bioaccumulation dynamics for major PCB and PBDE congeners (patterns and concentrations) and biotransformation capacity with respect to PCB metabolite formation and OH-PCB retention distinguished, to some extent, captive sledge dogs and wild polar bears. Based on the present findings, we conclude that the use of surrogate species in toxicological investigations for species in the Canoidea family should be done with great caution, although they remain essential in the context of contaminants research with sensitive arctic top carnivore species such as the polar bear.

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Scholars agree that governance of the public environment entails cooperation between science, policy and society. This requires the active role of public managers as catalysts of knowledge co-production, addressing participatory arenas in relation to knowledge integration and social learning. This paper deals with the question of whether public managers acknowledge and take on this task. A survey accessing Directors of Environmental Offices (EOs) of 64 municipalities was carried out in parallel for two regions - Tuscany (Italy) and Porto Alegre Metropolitan Region (Brazil). The survey data were analysed using the multiple correspondence method. Results showed that, regarding policy practices, EOs do not play the role of knowledge co-production catalysts, since when making environmental decisions they only use technical knowledge. We conclude that there is a gap between theory and practice, and identify some factors that may hinder local environmental managers in acting as catalyst of knowledge co-production, raising a further question for future research.

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The composition of algal pigments and extracellular polymeric substances (EPS) was determined in microbial mats from two lakes in Victoria Land (Continental Antarctica) with different lithology and environmental features. The aim was to expand knowledge of benthic autotrophic communities in Antarctic lacustrine ecosystems, providing reference data for future assessment of possible changes in environmental conditions and freshwater communities. The results of chemical analyses were supported by microscopy observations. Pigment profiles showed that filamentous cyanobacteria are dominant in both lakes. Samples from the water body at Edmonson Point had greater biodiversity, fewer pigments and lower EPS ratios than those from the lake at Kar Plateau. Differences in mat composition and in pigment and EPS profile between the two lakes are discussed in terms of local environmental conditions such as lithology, ice-cover and UV radiation. The present study suggests that a chemical approach could be useful in the study of benthic communities in Antarctic lakes and their variations in space and time.

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There is growing concern over the challenges for innovation in Freight Pipeline industry. Since the early works of Chesbrough a decade ago, we have learned a lot about the content, context and process of open innovation. However, much more research is needed in Freight Pipeline Industry. The reality is that few corporations have institutionalized open innovation practices in ways that have enabled substantial growth or industry leadership. Based on this, we pursue the following question: How does a firm’s integration into knowledge networks depend on its ability to manage knowledge? A competence-based model for freight pipeline organizations is analysed, this model should be understood by any organization in order to be successful in motivating professionals who carry out innovations and play a main role in collaborative knowledge creation processes. This paper aims to explain how can open innovation achieve its potential in most Freight Pipeline Industries.

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One of the advantages of social networks is the possibility to socialize and personalize the content created or shared by the users. In mobile social networks, where the devices have limited capabilities in terms of screen size and computing power, Multimedia Recommender Systems help to present the most relevant content to the users, depending on their tastes, relationships and profile. Previous recommender systems are not able to cope with the uncertainty of automated tagging and are knowledge domain dependant. In addition, the instantiation of a recommender in this domain should cope with problems arising from the collaborative filtering inherent nature (cold start, banana problem, large number of users to run, etc.). The solution presented in this paper addresses the abovementioned problems by proposing a hybrid image recommender system, which combines collaborative filtering (social techniques) with content-based techniques, leaving the user the liberty to give these processes a personal weight. It takes into account aesthetics and the formal characteristics of the images to overcome the problems of current techniques, improving the performance of existing systems to create a mobile social networks recommender with a high degree of adaptation to any kind of user.