5,882 research outputs found
MDI-QKD: Continuous- versus discrete-variables at metropolitan distances
In a comment, Xu, Curty, Qi, Qian, and Lo claimed that discrete-variable (DV)
measurement device independent (MDI) quantum key distribution (QKD) would
compete with its continuous-variable (CV) counterpart at metropolitan
distances. Actually, Xu et al.'s analysis supports exactly the opposite by
showing that the experimental rate of our CV protocol (achieved with practical
room-temperature devices) remains one order of magnitude higher than their
purely-numerical and over-optimistic extrapolation for qubits, based on
nearly-ideal parameters and cryogenic detectors (unsuitable solutions for a
realistic metropolitan network, which is expected to run on cheap
room-temperature devices, potentially even mobile). The experimental rate of
our protocol (expressed as bits per relay use) is confirmed to be two-three
orders of magnitude higher than the rate of any realistic simulation of
practical DV-MDI-QKD over short-medium distances. Of course this does not mean
that DV-MDI-QKD networks should not be investigated or built, but increasing
their rate is a non-trivial practical problem clearly beyond the analysis of Xu
et al. Finally, in order to clarify the facts, we also refute a series of
incorrect arguments against CV-MDI-QKD and, more generally, CV-QKD, which were
made by Xu et al. with the goal of supporting their thesis.Comment: Updated reply to Xu, Curty, Qi, Qian and Lo (arXiv:1506.04819),
including a point-to-point rebuttal of their new "Appendix E: Addendum
Development and Performance Evaluation of a Connected Vehicle Application Development Platform (CVDeP)
Connected vehicle (CV) application developers need a development platform to build,
test and debug real-world CV applications, such as safety, mobility, and environmental
applications, in edge-centric cyber-physical systems. Our study objective is to develop
and evaluate a scalable and secure CV application development platform (CVDeP)
that enables application developers to build, test and debug CV applications in realtime.
CVDeP ensures that the functional requirements of the CV applications meet the
corresponding requirements imposed by the specific applications. We evaluated the
efficacy of CVDeP using two CV applications (one safety and one mobility application)
and validated them through a field experiment at the Clemson University Connected
Vehicle Testbed (CU-CVT). Analyses prove the efficacy of CVDeP, which satisfies the
functional requirements (i.e., latency and throughput) of a CV application while
maintaining scalability and security of the platform and applications
Collaborating in virtual teams
Abstract. This paper describes some early results from observin
Photometric study of selected cataclysmic variables II. Time-series photometry of nine systems
We present time-series photometry of nine cataclysmic variables: EI UMa,
V844Her, V751 Cyg, V516 Cyg, GZ Cnc, TY Psc, V1315 Aql, ASAS J002511+1217.12,
V1315 Aql and LN UMa. The observations were conducted at various observatories,
covering 170 hours and comprising 7,850 data points in total.
For the majority of targets we confirm previously reported periodicities and
for some of them we give, for the first time, their spectroscopic orbital
periods. For those dwarf-nova systems which we observed during both quiescence
and outburst, the increase in brightness was followed by a decrease in the
amount of flickering. Quasi-periodic oscillations have either been discovered,
or were confirmed. For the eclipsing system V1315 Aql we have covered 9
eclipses, and obtained a refined orbital ephemeris. We find that, during its
long baseline of observations, no change in the orbital period of this system
has occurred. V1315 Aql also shows eclipses of variable depth.Comment: 30 pages, 16 figures, 4 tables. Submitted to JA
My private cloud--granting federated access to cloud resources
We describe the research undertaken in the six month JISC/EPSRC funded My Private Cloud project, in which we built a demonstration cloud file storage service that allows users to login to it, by using their existing credentials from a configured trusted identity provider. Once authenticated, users are shown a set of accounts that they are the owners of, based on their identity attributes. Once users open one of their accounts, they can upload and download files to it. Not only that, but they can then grant access to their file resources to anyone else in the federated system, regardless of whether their chosen delegate has used the cloud service before or not. The system uses standard identity management protocols, attribute based access controls, and a delegation service. A set of APIs have been defined for the authentication, authorisation and delegation processes, and the software has been released as open source to the community. A public demonstration of the system is available online
Investing in Entry-Level Talent
Even in today's competitive economic environment, there is much that companies can do to reduce entry-level turnover costs, increase employee engagement and retention, and create a talent pipeline for the future. Many companies pursue basic strategies to address turnover and promote advancement, such as offering competitive benefits and developing internal career paths. But our research found pioneering companies that are going beyond the basics and addressing turnover in remarkable ways. In examining the practices of these leading companies, we identified four strategies, outlined below, that markedly improve entry-level retention and advancement. This report is designed to share those strategies and practical suggestions for implementation with corporate leaders across the United States who are seeking to engage, retain, and advance their entry-level workforce
New Low Accretion-Rate Magnetic Binary Systems and their Significance for the Evolution of Cataclysmic Variables
Discoveries of two new white dwarf plus M star binaries with striking optical
cyclotron emission features from the Sloan Digital Sky Survey (SDSS) brings to
six the total number of X-ray faint, magnetic accretion binaries that accrete
at rates < 10^{-13} Msun/yr, or <1% of the values normally encountered in
cataclysmic variables. This fact, coupled with donor stars that underfill their
Roche lobes and very cool white dwarfs, brand the binaries as post
common-envelope systems whose orbits have not yet decayed to the point of
Roche-lobe contact. They are pre-magnetic CVs, or pre-Polars. The systems
exhibit spin/orbit synchronism and apparently accrete by efficient capture of
the stellar wind from the secondary star, a process that has been dubbed a
``magnetic siphon''. Because of this, period evolution of the binaries will
occur solely by gravitational radiation, which is very slow for periods >3 hr.
Optical surveys for the cyclotron harmonics appear to be the only means of
discovery, so the space density of pre-Polars could rival that of Polars, and
the binaries provide an important channel of progenitors (in addition to the
asynchronous Intermediate Polars). Both physical and SDSS observational
selection effects are identified that may help to explain the clumping of all
six systems in a narrow range of magnetic field strength around 60 MG.Comment: 25 pages, 13 figures, Accepted to Ap
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