107 research outputs found
Zero sequence blocking transformers for multi-pulse rectifier in aerospace applications
The second session of the 109th Congress may well face decisions regarding the preparation of U.S. military forces for stability missions, a broad doctrinal term of which a major subset is peace operations. A November 28, 2005, Department of Defense (DOD) directive that designates stability operations as “core missions” of the U.S. military marks a major shift on the future necessity of performing peacekeeping and related stability operations (also known as stabilization and reconstruction operations)
Decision table for classifying point sources based on FIRST and 2MASS databases
With the availability of multiwavelength, multiscale and multiepoch
astronomical catalogues, the number of features to describe astronomical
objects has increases. The better features we select to classify objects, the
higher the classification accuracy is. In this paper, we have used data sets of
stars and quasars from near infrared band and radio band. Then best-first
search method was applied to select features. For the data with selected
features, the algorithm of decision table was implemented. The classification
accuracy is more than 95.9%. As a result, the feature selection method improves
the effectiveness and efficiency of the classification method. Moreover the
result shows that decision table is robust and effective for discrimination of
celestial objects and used for preselecting quasar candidates for large survey
projects.Comment: 10 pages. accepted by Advances in Space Researc
Simulation of action potential propagation based on the ghost structure method
In this paper, a ghost structure (GS) method is proposed to simulate the monodomain model in irregular computational domains using finite difference without regenerating body-fitted grids. In order to verify the validity of the GS method, it is first used to solve the Fitzhugh-Nagumo monodomain model in rectangular and circular regions at different states (the stationary and moving states). Then, the GS method is used to simulate the propagation of the action potential (AP) in transverse and longitudinal sections of a healthy human heart, and with left bundle branch block (LBBB). Finally, we analyze the AP and calcium concentration under healthy and LBBB conditions. Our numerical results show that the GS method can accurately simulate AP propagation with different computational domains either stationary or moving, and we also find that LBBB will cause the left ventricle to contract later than the right ventricle, which in turn affects synchronized contraction of the two ventricles
Presynaptic regulation of the inhibitory transmission by GluR5-containing kainate receptors in spinal substantia gelatinosa
GluR5-containing kainate receptors (KARs) are known to be involved in nociceptive transmission. Our previous work has shown that the activation of presynaptic KARs regulates GABAergic and glycinergic synaptic transmission in cultured dorsal horn neurons. However, the role of GluR5-containing KARs in the modulation of inhibitory transmission in the spinal substantia gelatinosa (SG) in slices remains unknown. In the present study, pharmacological, electrophysiological and genetic methods were used to show that presynaptic GluR5 KARs are involved in the modulation of inhibitory transmission in the SG of spinal slices in vitro. The GluR5 selective agonist, ATPA, facilitated the frequency but not amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs) in SG neurons. ATPA increased sIPSC frequency in all neurons with different firing patterns as delayed, tonic, initial and single spike patterns. The frequency of either GABAergic or glycinergic sIPSCs was significantly increased by ATPA. ATPA could also induce inward currents in all SG neurons recorded. The frequency, but not amplitude, of action potential-independent miniature IPSCs (mIPSCs) was also facilitated by ATPA in a concentration-dependent manner. However, the effect of ATPA on the frequency of either sIPSCs or mIPSCs was abolished in GluR5(-/- )mice. Deletion of the GluR5 subunit gene had no effect on the frequency or amplitude of mIPSCs in SG neurons. However, GluR5 antagonist LY293558 reversibly inhibited sIPSC and mIPSC frequencies in spinal SG neurons. Taken together, these results suggest that GluR5 KARs, which may be located at presynaptic terminals, contribute to the modulation of inhibitory transmission in the SG. GluR5-containing KARs are thus important for spinal sensory transmission/modulation in the spinal cord
Selecting Quasar Candidates by a SVM Classification System
We develop and demonstrate a classification system constituted by several
Support Vector Machines (SVM) classifiers, which can be applied to select
quasar candidates from large sky survey projects, such as SDSS, UKIDSS, GALEX.
How to construct this SVM classification system is presented in detail. When
the SVM classification system works on the test set to predict quasar
candidates, it acquires the efficiency of 93.21% and the completeness of
97.49%. In order to further prove the reliability and feasibility of this
system, two chunks are randomly chosen to compare its performance with that of
the XDQSO method used for SDSS-III's BOSS. The experimental results show that
the high faction of overlap exists between the quasar candidates selected by
this system and those extracted by the XDQSO technique in the dereddened i-band
magnitude range between 17.75 and 22.45, especially in the interval of
dereddened i-band magnitude < 20.0. In the two test areas, 57.38% and 87.15% of
the quasar candidates predicted by the system are also targeted by the XDQSO
method. Similarly, the prediction of subcategories of quasars according to
redshift achieves a high level of overlap with these two approaches. Depending
on the effectiveness of this system, the SVM classification system can be used
to create the input catalog of quasars for the GuoShouJing Telescope (LAMOST)
or other spectroscopic sky survey projects. In order to get higher confidence
of quasar candidates, cross-result from the candidates selected by this SVM
system with that by XDQSO method is applicable.Comment: 11 pages, 4 figures and 7 tables, MNRAS accepte
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