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- Hall, Tomas, et al.
(författare)
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Performance Evaluation of KauNet in Physical and Virtual Emulation Environments
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Evaluation of applications and protocols in the context of computer networking is often necessary to determine the efficiency and level of service they can provide. In practical testing, three different options are available for the evaluation; using a physical network as a testbed, using an emulator to simplify the infrastructure, or using a simulator to remove reliance on infrastructure entirely. As a real network is costly and difficult or even impossible to create for every scenario, emulation and simulation is often used to approximate the behavior of a network with considerably less resources required. However, while a simulator is limited only by the time required to perform the simulation, an emulator is also limited by the hardware and software used. It is therefore important to evaluate the performance of the emulator itself, to determine its ability to emulate the desired network topologies.The focus of this document is the KauNet emulator, an extension of Dummynet that adds several new features, primarily deterministic emulation of various network characteristics through the use of pre-generated patterns. A series of tests were per- formed using a testbed with KauNet in both physical and virtual environments, as well as a hybrid environment with both physical and virtual machines. While virtualization greatly increases the flexbility and utilization of resources compared to a pure physical setup, it may also reduce the overall performance and accuracy of the emulation.From the results achieved, KauNet performs well in a physical environment, with a high degree of accuracy even at high traffic loads. Virtualization on the other hand, clearly introduces several issues with both processing and packet loss that may make it undesirable for use in experiments, although it may still be sufficient for scenarios where the requirements for accuracy are lower. The hybrid environment represents a compromise, with both performance and flexibility midway between the physical and fully virtualized testbed.
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- Nordang, Kirsten, et al.
(författare)
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Burnout in health-care professionals during reorganizations and downsizing. A cohort study in nurses
- 2010
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Ingår i: BMC Nursing. - London : BioMed Central. - 1472-6955 .- 1472-6955. ; 9:8, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundBurnout is a psychological reaction triggered by interaction between personal characteristics and stress factors. Reorganizations and downsizing with increased workload imply stress for health-care professionals. This is a study of burnout in nurses during a period with two comprehensive reorganizations. MethodsIn this quasi-experimental retrospective cohort study, burnout was assessed in nurses with long work experience in three surveys during a 30 months' period with two comprehensive reorganizations and downsizing of a hospital unit with mostly seriously ill patients with cancer. Burnout was measured with Bergen Burnout Indicator (BBI) at each survey, and "Sense of Coherence" (SOC) with Antonovsky's questionnaire at the last survey. ResultsOne man and 45 women aged 30 to 65 years were invited to the surveys. There was a significant increase in burnout during the study period, the mean increase in BBI-score was 12.5 pr year (p < 0.001). The proportion of satisfied nurses at the first and last survey were 84% and 35% respectively, and the proportions with burnout were 0% and 29% respectively (p < 0.001). Except for auxiliary nurses with experience from the medical department, all subgroups experienced a significant increase in BBI. Burnout was associated with low SOC (p < 0.001, r square 0.33). ConclusionsThere was a significant development of burnout in a group of nurses during a period with two reorganizations and downsizing. Burnout was associated with low SOC. Working with seriously ill patients with cancer has probably made the nurses exceptionally vulnerable to the stress and workload related to the reorganizations
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- Pérennou, Tanguy, et al.
(författare)
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Emulating Opportunistic Networks with KauNet Triggers
- 2011
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Ingår i: EURASIP Journal on Wireless Communications and Networking. - : Springer Science and Business Media LLC. - 1687-1472 .- 1687-1499. ; 2011
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Tidskriftsartikel (refereegranskat)abstract
- In opportunistic networks, the availability of an end-to-end path is no longer required. Instead opportunistic networks may take advantage of temporary connectivity opportunities. Opportunistic networks present a demanding environment for network emulation as the traditional emulation setup, where application/transport endpoints only send and receive packets from the network following a black box approach, is no longer applicable. Opportunistic networking protocols and applications additionally need to react to the dynamics of the underlying network beyond what is conveyed through the exchange of packets. In order to support IP-level emulation evaluations of applications and protocols that react to lower layer events, we have proposed the use of emulation triggers. Emulation triggers can emulate arbitrary cross-layer feedback and can be synchronized with other emulation effects. After introducing the design and implementation of triggers in the KauNet emulator, we describe the integration of triggers with the DTN2 reference implementation and illustrate how the functionality can be used to emulate a classical DTN data-mule scenario.
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