1,880 research outputs found
Visualization of Big Spatial Data using Coresets for Kernel Density Estimates
The size of large, geo-located datasets has reached scales where
visualization of all data points is inefficient. Random sampling is a method to
reduce the size of a dataset, yet it can introduce unwanted errors. We describe
a method for subsampling of spatial data suitable for creating kernel density
estimates from very large data and demonstrate that it results in less error
than random sampling. We also introduce a method to ensure that thresholding of
low values based on sampled data does not omit any regions above the desired
threshold when working with sampled data. We demonstrate the effectiveness of
our approach using both, artificial and real-world large geospatial datasets
User-Centered Evaluation of Adaptive and Adaptable Systems
Adaptive and adaptable systems provide tailored output to various users in various contexts. While adaptive systems base their output on implicit inferences, adaptable systems use explicitly provided information. Since the presentation or output of these systems is adapted, standard user-centered evaluation methods do not produce results that can be easily generalized. This calls for a reflection on the appropriateness of standard evaluation methods for user-centered evaluations of these systems. We have conducted a literature review to create an overview of the methods that have been used. When reviewing the empirical evaluation studies we have, among other things, focused on the variables measured and the implementation of results in the (re)design process. The goal of our review has been to compose a framework for user-centered evaluation. In the next phase of the project, we intend to test some of the most valid and feasible methods with an adaptive or adaptable system
The star formation history of RCW 36
Recent studies of massive-star forming regions indicate that they can contain
multiple generations of young stars. These observations suggest that star
formation in these regions is sequential and/or triggered by a previous
generation of (massive) stars. Here we present new observations of the star
forming region RCW 36 in the Vela Molecular Ridge, hosting a young cluster of
massive stars embedded in a molecular cloud complex. In the periphery of the
cluster several young stellar objects (YSOs) are detected which produce bipolar
jets (HH 1042 and HH 1043) demonstrating that these objects are still actively
accreting. The VLT/X-shooter spectrum of the jet structure of HH 1042 provides
detailed information on the physical conditions and kinematical properties of
the jet plasma. From this information the YSO's accretion history can be
derived. Combining the photometric and spectroscopic observations of RCW 36
gives insight into the formation process of individual stars and the star
formation history of this young massive-star forming region.Comment: 10 pages, 5 figures, to appear in the proceedings of the ESO workshop
"Circumstellar Dynamics at High Resolution", Foz do Iguacu (Br), Feb 2012,
eds. A. Carciofi and T. Riviniu
Of Wine and War: The Fall of State Twenty-first Amendment Power at the Hands of the Dormant Commerce Clause—Granholm v. Heald
This publication contains may contain links to external sites. These external sites may no longer be active.Made available by the Northern Territory Library via the Publications (Legal Deposit) Act 2004 (NT).This publication contains many links to external sites. These external sites may no longer be active
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