1,400 research outputs found
Classification under Streaming Emerging New Classes: A Solution using Completely Random Trees
This paper investigates an important problem in stream mining, i.e.,
classification under streaming emerging new classes or SENC. The common
approach is to treat it as a classification problem and solve it using either a
supervised learner or a semi-supervised learner. We propose an alternative
approach by using unsupervised learning as the basis to solve this problem. The
SENC problem can be decomposed into three sub problems: detecting emerging new
classes, classifying for known classes, and updating models to enable
classification of instances of the new class and detection of more emerging new
classes. The proposed method employs completely random trees which have been
shown to work well in unsupervised learning and supervised learning
independently in the literature. This is the first time, as far as we know,
that completely random trees are used as a single common core to solve all
three sub problems: unsupervised learning, supervised learning and model update
in data streams. We show that the proposed unsupervised-learning-focused method
often achieves significantly better outcomes than existing
classification-focused methods
Multi-particle azimuthal cumulants from transverse momentum conservation and collective flow
We calculate the th order of -particle azimuthal cumulants
based on transverse momentum conservation (TMC) and collective flow
(n=2,3). We demonstrate that the TMC effect only leads to a nonzero
with the sign of and the magnitude inversely
proportional to . The interplay between TMC and collective flow
can change the signs of , and at some values of
multiplicity , which could provide a good probe to study the onset of
collectivity and search for the substructure of proton in small colliding
systems.Comment: 11 pages, 3 figure
Different Binding Orientations for the Same Agonist at Homologous Receptors: A Lock and Key or a Simple Wedge?
Using unnatural amino acid mutagenesis, the binding site for serotonin at the novel Caenorhabditis elegans receptor MOD-1 has been probed. As with the closely related serotonin receptor 5-HT_3, MOD-1 makes use of a strong cation−π interaction between the ammonium of serotonin and the indole side chain of a tryptophan. However, the specific Trp used by MOD-1 is different from that used for 5-HT_3 (and the nAChR), aligning with a residue more than 40 amino acids distant in sequence space and on a different “loop” of the agonist binding site. This suggests a significant rearrangement of the ligand on binding these two closely related receptors. It is suggested that, unlike enzymes, receptors and other signaling molecules may need only to deliver an agonist to a general binding region, rather than establishing precise drug−receptor interactions
Resonant Spin Polarization and Hall Effects in a Two-Dimensional Electron Gas
We have studied transport properties in a two-dimensional electron gas with
equal Rashba and Dresselhaus spin-orbit interactions under a perpendicular
magnetic field. By employing the exact solution for this system, we found
resonant charge and spin Hall conductances at a certain magnetic field, where
all the nearest-neighboring Landau levels cross. Near this value of magnetic
field, there exists a resonant spin polarization, which can also induce
resonant charge and spin Hall effects.Comment: 4 pages, 2 figure
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