3,700 research outputs found
Global-Scale Resource Survey and Performance Monitoring of Public OGC Web Map Services
One of the most widely-implemented service standards provided by the Open
Geospatial Consortium (OGC) to the user community is the Web Map Service (WMS).
WMS is widely employed globally, but there is limited knowledge of the global
distribution, adoption status or the service quality of these online WMS
resources. To fill this void, we investigated global WMSs resources and
performed distributed performance monitoring of these services. This paper
explicates a distributed monitoring framework that was used to monitor 46,296
WMSs continuously for over one year and a crawling method to discover these
WMSs. We analyzed server locations, provider types, themes, the spatiotemporal
coverage of map layers and the service versions for 41,703 valid WMSs.
Furthermore, we appraised the stability and performance of basic operations for
1210 selected WMSs (i.e., GetCapabilities and GetMap). We discuss the major
reasons for request errors and performance issues, as well as the relationship
between service response times and the spatiotemporal distribution of client
monitoring sites. This paper will help service providers, end users and
developers of standards to grasp the status of global WMS resources, as well as
to understand the adoption status of OGC standards. The conclusions drawn in
this paper can benefit geospatial resource discovery, service performance
evaluation and guide service performance improvements.Comment: 24 pages; 15 figure
Glueball relevant study on isoscalars from lattice QCD
We perform a glueball-relevant study on isoscalars based on anisotropic
lattice QCD gauge configurations. In the scalar channel, we identify
the ground state obtained through gluonic operators to be a single-particle
state through its dispersion relation. When operator is included, we
find the mass of this state does not change, and the operator
couples very weakly to this state. So this state is most likely a glueball
state. For pseudoscalars, along with the exiting lattice results, our study
implies that both the conventional state (or in
flavor ) and a heavier glueball-like state with a mass of roughly 2.6
GeV exist in the spectrum of lattice QCD with dynamical quarks.Comment: 8 pages, 3 figures, 3 tables, talk presented at the 35th
International Symposium on Lattice Field Theory, 18-24 June 2017, Granada,
Spai
Canonical interpretation of and in the family
Inspired by the new resonance , we calculate the masses and
two-body OZI-allowed strong decays of the higher vector bottomonium sates
within both screened and linear potential models. We discuss the possibilities
of and as mixed states via the mixing. Our
results suggest that and might be explained as
mixed states between - and -wave vector states. The
and resonances may correspond to the mixed states
dominated by the - and -wave components, respectively. The mass and the
strong decay behaviors of the resonance are consistent with
the assignment of the state in the potential models.Comment: 9 pages, 4 figures. More discussions are adde
Lattice study on and X(3872)
Properties of charmonium are investigated in quenched
lattice QCD. The mass of is determined to be 3.80(3) GeV, which is
close to the mass of -wave charmonium and in agreement with
quark model predictions. The transition width of
is also obtained with a value keV. Since the possible
assignment to X(3872) has not been ruled out by experiments, our results help
to clarify the nature of X(3872).Comment: 15 pages, 8 figures. typos, grammatical errors and some references
corrected, redundant discussions deleted, conclusion does not change.
published versio
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