4,613 research outputs found

    Qualitative telephone interviews: Strategies for success

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    The use of the telephone in qualitative interviews is discouraged by traditionalists who view it as an inferior data collection instrument. However these claims have not been supported by empirical evidence and qualitative researchers who have used and compared the telephone to the face-to-face mode of interviewing present a different story. This study attempts to build on the limited existing research comparing the issues involved and the data collected using the telephone and face-to-face interview modes. The study evaluates the criticisms of traditionalists in the light of existing research. The study then presents the observations of the researcher based on a research project that involved 43 telephone, 1 Skype and 6 face-to-face interviews. These observations as well as the limited prior research are used to develop strategies for the effective use telephone interviews in qualitative research. The study concludes that for certain studies the telephone if used with the strategies recommended here provides qualitative researchers with a sound data collection instrument

    Higgs properties measurements using the four lepton decay channel

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    The measurements of the properties of the Higgs boson are presented in the H\rightarrowZZ\rightarrow4\ell (\ell=e,μ\mu) decay channel using a data sample corresponding to an integrated luminosity of 35.9 fb1^{-1} of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the CMS detector at the LHC. The signal-strength modifier μ\mu, defined as the production cross section of the Higgs boson times its branching fraction to four leptons relative to the standard model expectation, is measured to be μ=1.050.17+0.19\mu=1.05^{+0.19}_{-0.17} at mH=125.09 GeVm_{\mathrm{H}}=125.09~\mathrm{GeV}. Constraints are set on the strength modifiers for the main Higgs boson production modes. The mass is measured to be mH=125.26±0.21 GeVm_{\mathrm{H}}=125.26 \pm 0.21~\mathrm{GeV} and the width is constrained using on-shell production to be ΓH<1.10 GeV\Gamma_{\mathrm{H}}<1.10~\mathrm{GeV}, at 95%95\% CL. The fiducial cross section is measured to be 2.900.44+0.48(stat.)0.22+0.27(sys.) fb2.90^{+0.48}_{-0.44}({\rm stat.})^{+0.27}_{-0.22}({\rm sys.})~{\mathrm{fb}}, which is compatible with the standard model prediction of 2.72±0.14 fb2.72\pm0.14~{\mathrm{fb}}.Comment: Presented at LHCP201

    An Authentication Protocol for Future Sensor Networks

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    Authentication is one of the essential security services in Wireless Sensor Networks (WSNs) for ensuring secure data sessions. Sensor node authentication ensures the confidentiality and validity of data collected by the sensor node, whereas user authentication guarantees that only legitimate users can access the sensor data. In a mobile WSN, sensor and user nodes move across the network and exchange data with multiple nodes, thus experiencing the authentication process multiple times. The integration of WSNs with Internet of Things (IoT) brings forth a new kind of WSN architecture along with stricter security requirements; for instance, a sensor node or a user node may need to establish multiple concurrent secure data sessions. With concurrent data sessions, the frequency of the re-authentication process increases in proportion to the number of concurrent connections, which makes the security issue even more challenging. The currently available authentication protocols were designed for the autonomous WSN and do not account for the above requirements. In this paper, we present a novel, lightweight and efficient key exchange and authentication protocol suite called the Secure Mobile Sensor Network (SMSN) Authentication Protocol. In the SMSN a mobile node goes through an initial authentication procedure and receives a re-authentication ticket from the base station. Later a mobile node can use this re-authentication ticket when establishing multiple data exchange sessions and/or when moving across the network. This scheme reduces the communication and computational complexity of the authentication process. We proved the strength of our protocol with rigorous security analysis and simulated the SMSN and previously proposed schemes in an automated protocol verifier tool. Finally, we compared the computational complexity and communication cost against well-known authentication protocols.Comment: This article is accepted for the publication in "Sensors" journal. 29 pages, 15 figure