29,763 research outputs found
Feature and Region Selection for Visual Learning
Visual learning problems such as object classification and action recognition
are typically approached using extensions of the popular bag-of-words (BoW)
model. Despite its great success, it is unclear what visual features the BoW
model is learning: Which regions in the image or video are used to discriminate
among classes? Which are the most discriminative visual words? Answering these
questions is fundamental for understanding existing BoW models and inspiring
better models for visual recognition.
To answer these questions, this paper presents a method for feature selection
and region selection in the visual BoW model. This allows for an intermediate
visualization of the features and regions that are important for visual
learning. The main idea is to assign latent weights to the features or regions,
and jointly optimize these latent variables with the parameters of a classifier
(e.g., support vector machine). There are four main benefits of our approach:
(1) Our approach accommodates non-linear additive kernels such as the popular
and intersection kernel; (2) our approach is able to handle both
regions in images and spatio-temporal regions in videos in a unified way; (3)
the feature selection problem is convex, and both problems can be solved using
a scalable reduced gradient method; (4) we point out strong connections with
multiple kernel learning and multiple instance learning approaches.
Experimental results in the PASCAL VOC 2007, MSR Action Dataset II and YouTube
illustrate the benefits of our approach
In situ Assessment of Support and Drainage for PCC Subbase
Design and maintenance of pavement drainage is critical to ensure the long service life of pavements. A minimum assumed coefficient of saturated hydraulic conductivity (Ksat) value of the base materials is used to design the aggregate base/subbase layer geometry (i.e., thickness, width and slop). However, ksat is often a single assumed value used during design and is not field verified. ksat is typically either measured on small volume of material in the lab or estimated by using empirical relationships. Both methods do not adequately capture the field variability.
In this study, a gas permeability test (GPT) device that has been recently designed and fabricated at Iowa State University is used to evaluate the hydraulic conductivity of pavement base materials in the field and laboratory. Field studies were conducted on newly constructed base layers projects in IA, MI and PA. Field testing conducted in MI and PA involved capturing the spatial of fines content and ksat variability over a relatively small area (smaller than 10 m by 10m area). Field testing in Iowa involved evaluating the effect of construction operations for placement or granular base/subbase on fine content, ksat, density and stiffness (i.e., number of passes, compaction using vibration, and static compaction). Laboratory studies were conducted using various materials to validate the gas permeability test (GPT) measurements by conductivity conventional laboratory falling and constant head testing. The difference between in situ and laboratory data was compared to complete the design parameter derivations, and effects of the pavement performance.
Results indicated that GPT is repeatable (ksat of COV yy 1%) on a series of repeatability tests conducted on a material and has a wide range of ksat values (0.1 to 820 cm/sec)
On a certain non-split cubic surface
In this note, we establish an asymptotic formula for the number of rational
points of bounded height on the singular cubic surface with a power-saving error term, which verifies the Manin-Peyre
conjectures for this surface.Comment: v2. 18 pages, one author adde
Compton-thick AGN in the NuSTAR era II: A deep NuSTAR and XMM-Newton view of the candidate Compton thick AGN in NGC 1358
We present the combined NuSTATR and XMM-Newton 0.6-79 keV spectral analysis
of a Seyfert 2 galaxy, NGC 1358, which we selected as a candidate Compton thick
(CT-) active galactic nucleus (AGN) on the basis of previous Swift/BAT and
Chandra studies. According to our analysis, NGC 1358 is confirmed to be a
CT-AGN using physical motivated models, at >3 confidence level. Our
best-fit shows that the column density along the 'line-of-sight' of the
obscuring material surrounding the accreting super-massive black hole is N = [1.96--2.80] 10 cm. The high-quality data from
NuSTAR gives the best constraints on the spectral shape above 10 keV to
date on NGC 1358. Moreover, by combining NuSTAR and XMM-Newton data, we find
that the obscuring torus has a low covering factor ( <0.17), and the
obscuring material is distributed in clumps, rather than uniformly. We also
derive an estimate of NGC 1358's Eddington ratio, finding it to be
10, which is in
acceptable agreement with previous measurements. Finally, we find no evidence
of short-term variability, over a 100 ks time-span, in terms of both
'line-of-sight' column density and flux.Comment: 12 pages, 6 figure
Assessment of the quantitative accuracy of Rietveld/XRD analysis of crystalline and amorphous phases in fly ash
An internal standard method based on Rietveld/XRD whole-pattern fitting analysis of fly ash is used to assess
the quantitative accuracy to determine its crystalline and amorphous phases under various conditions such
as internal standards (types, SiO2 or Al2O3 and dosages, 10–50%), incident X-rays (laboratory or
synchrotron) and refinement software (GSAS or TOPAS). The results reveal that the quantitative stability is
quite sensible to minor phases, identical to the internal standard, in fly ash. Errors positively correlate
with the weight fraction of that minor phase and negatively correlate with the dosage of an internal
standard and amorphous phase content in fly ash. The original equation for the amorphous phase
calculation is not applicable for a case with a higher inherent quartz content (>2.5%) in fly ash while the
dosages of the internal standard is lower than 20%. The original equation is modified as proposed. Based
on it, the quantitative results of five different patterns report a good reproducibility with the arithmetic
mean errors and the standard errors of identified main phases of around 1%.The access to the beamline BL14B1 facilities at the SSRF is
appreciated and the support of SSRF management, User Office
and beamline staff is highly appreciated. This Research is
supported by the National Natural Science Foundation of China
(No. 51602126), the National Key Research and Development
Plan of China (2016YFB0303505) and the Program for Scientic
Research Innovation Team in Colleges and Universities of
Shandong Province
Clinical Application of In Vitro Maturation of Oocytes
In vitro maturation (IVM) is a technique used to induce immature oocytes collected in different periods of embryonic growth. The rates vary for immature oocytes collected from different clinical sources to potentially develop into embryos and achieve live birth. As an effective treatment method, IVM can be used to treat patients with polycystic ovary syndrome (PCOS), ovarian hyperresponsiveness, and hyporesponsiveness, as well as to preserve the fertility of cancer patients. This technology has been used worldwide for the birth of thousands of healthy babies. The improvement in clinical IVM technology mainly focuses on the IVM medium and the optimization of the culture environment and operation process. At present, with the improvement in the in vitro fertilization (IVF) efficiency and culture systems, a natural cycle or mild stimulation may be more suitable for women receiving IVF treatments. A new treatment option was proposed to combine natural cycle/mild stimulation IVF with IVM. In particular, the combination of mild stimulation IVF and IVM is not only expected to become a viable alternative to current standard treatments but may also become a potential option of first-line treatment
Spin-Phonon Coupling in Iron Pnictide Superconductors
The magnetic moment in the parent phase of the iron-pnictide superconductors
varies with composition even when the nominal charge of iron is unchanged. We
propose the spin-lattice coupling due to the magneto-volume effect as the
primary origin of this effect, and formulate a Landau theory to describe the
dependence of the moment to the Fe-As layer separation. We then compare the
superconductive critical temperature of doped iron pnictides to the local
moment predicted by the theory, and suggest that the spin-phonon coupling may
play a role in the superconductivity of this compound
Proof of a Stable Fixed Point for Strongly Correlated Electron Matter
We establish the Hatsugai-Kohmoto model as a stable quartic fixed point
(distinct from Wilson-Fisher) by computing the function in the presence
of perturbing local interactions. In vicinity of the half-filled doped Mott
state, the function vanishes for all local interactions regardless of
their sign. The only flow away from the HK model is through the superconducting
channel which lifts the spin degeneracy as does any ordering tendency. The
superconducting instability is identical to that established
previously\cite{nat1}. A corollary of this work is that Hubbard repulsive
interactions flow into the HK stable fixed point in the vicinity of
half-filling. Consequently, although the HK model has all-to-all interactions,
nothing local destroys it. The consilience with Hubbard arises because both
models break the symmetry on a Fermi surface, the HK model being the
simplest to do so. Indeed, the simplicity of the HK model belies its robustness
and generality
- …