26,445 research outputs found
Minimalist AdaBoost for blemish identification in potatoes
We present a multi-class solution based on minimalist Ad-
aBoost for identifying blemishes present in visual images of potatoes.
Using training examples we use Real AdaBoost to rst reduce the fea-
ture set by selecting ve features for each class, then train binary clas-
siers for each class, classifying each testing example according to the
binary classier with the highest certainty. Against hand-drawn ground
truth data we achieve a pixel match of 83% accuracy in white potatoes
and 82% in red potatoes. For the task of identifying which blemishes
are present in each potato within typical industry dened criteria (10%
coverage) we achieve accuracy rates of 93% and 94%, respectively
Ultrasensitive mechanical detection of magnetic moment using a commercial disk drive write head
Sensitive detection of weak magnetic moments is an essential capability in
many areas of nanoscale science and technology, including nanomagnetism,
quantum readout of spins, and nanoscale magnetic resonance imaging. Here, we
show that the write head of a commercial hard drive may enable significant
advances in nanoscale spin detection. By approaching a sharp diamond tip to
within 5 nm from the pole and measuring the induced diamagnetic moment with a
nanomechanical force transducer, we demonstrate a spin sensitivity of 0.032
Bohr magnetons per root Hz, equivalent to 21 proton magnetic moments. The high
sensitivity is enabled in part by the pole's strong magnetic gradient of up to
28 million Tesla per meter and in part by the absence of non-contact friction
due to the extremely flat writer surface. In addition, we demonstrate
quantitative imaging of the pole field with about 10 nm spatial resolution. We
foresee diverse applications for write heads in experimental condensed matter
physics, especially in spintronics, ultrafast spin manipulation, and mesoscopic
physics.Comment: 21 pages, 6 figure
Spectroscopy of reflection-asymmetric nuclei with relativistic energy density functionals
Quadrupole and octupole deformation energy surfaces, low-energy excitation
spectra and transition rates in fourteen isotopic chains: Xe, Ba, Ce, Nd, Sm,
Gd, Rn, Ra, Th, U, Pu, Cm, Cf, and Fm, are systematically analyzed using a
theoretical framework based on a quadrupole-octupole collective Hamiltonian
(QOCH), with parameters determined by constrained reflection-asymmetric and
axially-symmetric relativistic mean-field calculations. The microscopic QOCH
model based on the PC-PK1 energy density functional and -interaction
pairing is shown to accurately describe the empirical trend of low-energy
quadrupole and octupole collective states, and predicted spectroscopic
properties are consistent with recent microscopic calculations based on both
relativistic and non-relativistic energy density functionals. Low-energy
negative-parity bands, average octupole deformations, and transition rates show
evidence for octupole collectivity in both mass regions, for which a
microscopic mechanism is discussed in terms of evolution of single-nucleon
orbitals with deformation.Comment: 36 pages, 21 figures, Accepted for Publication in Physical Review
Local Protectionism and Regional Specialization: Evidence from China’s Industries
This paper uses a dynamic panel estimation method to investigate the determinants of regional specialization in China’s industries, paying particular attention to local protectionism. Less geographic concentration is found in industries where the past tax-plus-profit margins and the shares of state ownership are high, re- flecting stronger local government protection of these industries. The evidence also supports the scale-economies theory of regional specialization. Finally, the overall time trend of regional specialization of China’s industries is found to have reversed an early drop in the mid 1980s, and registered a significant increase in the later years.http://deepblue.lib.umich.edu/bitstream/2027.42/39951/3/wp565.pd
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