1,283 research outputs found
Note: An object detection method for active camera
To solve the problems caused by a changing background during object detection in active camera, this paper proposes a new method based on SURF (speeded up robust features) and data clustering. The SURF feature points of each image are extracted, and each cluster center is calculated by processing the data clustering of k adjacent frames. Templates for each class are obtained by calculating the histograms within the regions around the center points of the clustering classes. The window of the moving object can be located by finding the region that satisfies the histogram matching result between adjacent frames. Experimental results demonstrate that the proposed method can improve the effectiveness of object detection.Yong Chen, Ronghua Zhang, Lei Shang, and Eric H
A Semantics-Based Measure of Emoji Similarity
Emoji have grown to become one of the most important forms of communication
on the web. With its widespread use, measuring the similarity of emoji has
become an important problem for contemporary text processing since it lies at
the heart of sentiment analysis, search, and interface design tasks. This paper
presents a comprehensive analysis of the semantic similarity of emoji through
embedding models that are learned over machine-readable emoji meanings in the
EmojiNet knowledge base. Using emoji descriptions, emoji sense labels and emoji
sense definitions, and with different training corpora obtained from Twitter
and Google News, we develop and test multiple embedding models to measure emoji
similarity. To evaluate our work, we create a new dataset called EmoSim508,
which assigns human-annotated semantic similarity scores to a set of 508
carefully selected emoji pairs. After validation with EmoSim508, we present a
real-world use-case of our emoji embedding models using a sentiment analysis
task and show that our models outperform the previous best-performing emoji
embedding model on this task. The EmoSim508 dataset and our emoji embedding
models are publicly released with this paper and can be downloaded from
http://emojinet.knoesis.org/.Comment: This paper is accepted at Web Intelligence 2017 as a full paper, In
2017 IEEE/WIC/ACM International Conference on Web Intelligence (WI). Leipzig,
Germany: ACM, 201
Theory Challenges of the Accelerating Universe
The accelerating expansion of the universe presents an exciting, fundamental
challenge to the standard models of particle physics and cosmology. I highlight
some of the outstanding challenges in both developing theoretical models and
interpreting without bias the observational results from precision cosmology
experiments in the next decade that will return data to help reveal the nature
of the new physics. Examples given focus on distinguishing a new component of
energy from a new law of gravity, and the effect of early dark energy on baryon
acoustic oscillations.Comment: 10 pages, 4 figures; minor changes to match J. Phys. A versio
Coulomb Gaps in One-Dimensional Spin-Polarized Electron Systems
We investigate the density of states (DOS) near the Fermi energy of
one-dimensional spin-polarized electron systems in the quantum regime where the
localization length is comparable to or larger than the inter-particle
distance. The Wigner lattice gap of such a system, in the presence of weak
disorder, can occur precisely at the Fermi energy, coinciding with the Coulomb
gap in position. The interplay between the two is investigated by treating the
long-range Coulomb interaction and the random disorder potential in a
self-consistent Hartree-Fock approximation. The DOS near the Fermi energy is
found to be well described by a power law whose exponent decreases with
increasing disorder strength.Comment: 4 pages, revtex, 4 figures, to be published in Phys. Rev. B as a
Rapid Communicatio
Quantum-Hall Quantum-Bits
Bilayer quantum Hall systems can form collective states in which electrons
exhibit spontaneous interlayer phase coherence. We discuss the possibility of
using bilayer quantum dot many-electron states with this property to create
two-level systems that have potential advantages as quantum bits.Comment: 4 pages, 4 figures included, version to appear in Phys. Rev. B (Rapid
Communications
Intakes of fruits, vegetables and carbohydrate and the risk of CVD
BACKGROUND: Low-carbohydrate diets could lead to reduced fruit and vegetable intake, which may be protective against CVD. The role of carbohydrate intake in modifying the association between fruits and vegetables and CVD has not been evaluated. OBJECTIVE: To evaluate whether carbohydrate intake affects the association between fruits and vegetables and CVD. DESIGN: We included participants from two large prospective studies, the Nurses' Health Study (NHS) and the Health Professionals' Follow-Up Study (HPFS). We followed 70870 eligible NHS females for 16 years and 38918 eligible HPFS males for 14 years. Diet was assessed from an FFQ updated every 4 years. Our primary outcome was ischaemic CVD (fatal and non-fatal myocardial infarction and ischaemic stroke). We used Cox proportional hazards models to evaluate the relationship between fruits and vegetables and ischaemic CVD within groups with low, moderate or high carbohydrate intake. RESULTS: Fruit intake was strongly related with carbohydrate intake, but vegetables showed a very small correlation. Vegetable intake showed stronger associations with ischaemic CVD among the low carbohydrate group (multivariate risk ratio (RR) = 0.82 for an increment of 3 servings/d; 95% CI 0.68, 0.99); green leafy vegetables and carotene-rich fruits and vegetables followed a similar pattern. Total fruit intake was associated with a lower risk of ischaemic CVD only among participants with moderate carbohydrate intake (RR = 0.81 comparing extreme quintiles; 95% CI 0.70, 0.94). CONCLUSIONS: Total vegetables, green leafy vegetables and carotene-rich fruits and vegetables showed stronger associations with ischaemic CVD among the low carbohydrate group. No consistent trends were observed for fruit intake
Simulating Interface Growth and Defect Generation in CZT β Simulation State of the Art and Known Gaps
This one-year, study topic project will survey and investigate the known state-of-the-art of modeling and simulation methods suitable for performing fine-scale, fully 3-D modeling, of the growth of CZT crystals at the melt-solid interface, and correlating physical growth and post-growth conditions with generation and incorporation of defects into the solid CZT crystal. In the course of this study, this project will also identify the critical gaps in our knowledge of modeling and simulation techniques in terms of what would be needed to be developed in order to perform accurate physical simulations of defect generation in melt-grown CZT. The transformational nature of this study will be, for the first time, an investigation of modeling and simulation methods for describing microstructural evolution during crystal growth and the identification of the critical gaps in our knowledge of such methods, which is recognized as having tremendous scientific impacts for future model developments in a wide variety of materials science areas
The epsilon Chamaeleontis young stellar group and the characterization of sparse stellar clusters
We present the outcomes of a Chandra X-ray Observatory snapshot study of five
nearby Herbig Ae/Be (HAeBe) stars which are kinematically linked with the
Oph-Sco-Cen Association (OSCA). Optical photometric and spectroscopic followup
was conducted for the HD 104237 field. The principal result is the discovery of
a compact group of pre-main sequence (PMS) stars associated with HD 104237 and
its codistant, comoving B9 neighbor epsilon Chamaeleontis AB. We name the group
after the most massive member. The group has five confirmed stellar systems
ranging from spectral type B9-M5, including a remarkably high degree of
multiplicity for HD 104237 itself. The HD 104237 system is at least a quintet
with four low mass PMS companions in nonhierarchical orbits within a projected
separation of 1500 AU of the HAeBe primary. Two of the low-mass members of the
group are actively accreting classical T Tauri stars. The Chandra observations
also increase the census of companions for two of the other four HAeBe stars,
HD 141569 and HD 150193, and identify several additional new members of the
OSCA.
We discuss this work in light of several theoretical issues: the origin of
X-rays from HAeBe stars; the uneventful dynamical history of the
high-multiplicity HD 104237 system; and the origin of the epsilon Cha group and
other OSCA outlying groups in the context of turbulent giant molecular clouds.
Together with the similar eta Cha cluster, we paint a portrait of sparse
stellar clusters dominated by intermediate-mass stars 5-10 Myr after their
formation.Comment: Accepted for publication in the Astrophysical Journal. 32 pages and 7
figure
Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.
BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
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