4,293 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
Designing and conducting an open-ended experiment as an organic chemistry laboratory practical
An open-ended laboratory practical has been developed that challenges students to evaluate the synthesis of aspirin, which is a typical experiment of organic synthesis. In contrast to a traditional textbook laboratory practical, the overall grade includes an evaluation of the experimental preparation, process, report, and PowerPoint presentation of the student. This practical improves undergraduate students’ ability to think innovatively and the skills pertaining for team cooperation, which would exhibit importance in the organic chemistry teaching experiment’s course
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
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