557 research outputs found
Estimates of Invariant Metrics on Pseudoconvex Domains of Finite Type in C
Let Ω be a smoothly bounded pseudoconvex domain in C3 and assume that z0âbΩ is a point of finite 1-type in the sense of DâAngelo. Then, there are an admissible curve ÎâΩâȘ{z0}, connecting pointsââq0âΩ and z0âbΩ, and a quantity M(z,X), along zâÎ, which bounds from above and below the Bergman, Caratheodory, and Kobayashi metrics in a small constant and large constant sense
On Sharp Hölder Estimates of the Cauchy-Riemann Equation on Pseudoconvex Domains in C
Let Ω be a smoothly bounded pseudoconvex domain in Cn with one degenerate eigenvalue and assume that there is a smooth holomorphic curve V whose order of contact with bΩ at z0âbΩ is larger than or equal to η. We show that the maximal gain in Hölder regularity for solutions of the âÂŻ-equation is at most 1/η
Discriminative Feature Learning for Unsupervised Video Summarization
In this paper, we address the problem of unsupervised video summarization
that automatically extracts key-shots from an input video. Specifically, we
tackle two critical issues based on our empirical observations: (i) Ineffective
feature learning due to flat distributions of output importance scores for each
frame, and (ii) training difficulty when dealing with long-length video inputs.
To alleviate the first problem, we propose a simple yet effective
regularization loss term called variance loss. The proposed variance loss
allows a network to predict output scores for each frame with high discrepancy
which enables effective feature learning and significantly improves model
performance. For the second problem, we design a novel two-stream network named
Chunk and Stride Network (CSNet) that utilizes local (chunk) and global
(stride) temporal view on the video features. Our CSNet gives better
summarization results for long-length videos compared to the existing methods.
In addition, we introduce an attention mechanism to handle the dynamic
information in videos. We demonstrate the effectiveness of the proposed methods
by conducting extensive ablation studies and show that our final model achieves
new state-of-the-art results on two benchmark datasets.Comment: Accepted to AAAI 2019 !!
Cancer Patientsâ Utilization of Tertiary Hospitals in Seoul Before and After the Benefit Expansion Policy
Objectives The aim of this study was to investigate cancer patientsâ utilization of tertiary hospitals in Seoul before and after the benefit expansion policy implemented in 2013. Methods This was a before-and-after study using claims data of the Korean National Health Insurance Service from 2011 to 2016. The unit of analysis was inpatient episodes, and inpatient episodes involving a malignant neoplasm (International Classification of Diseases, Tenth Revision codes: C00-C97) were included in this study. The total sample (n=5 565 076) was divided into incident cases and prevalent cases according to medical use due to cancer in prior years. The tertiary hospitals in Seoul were divided into two groups (the five largest hospitals and the other tertiary hospitals in Seoul). Results The proportions of the incident and prevalent episodes occurring in tertiary hospitals in Seoul were 34.9% and 37.2%, respectively, of which more than 70% occurred in the five largest hospitals in Seoul. Utilization of tertiary hospitals in Seoul was higher for inpatient episodes involving cancer surgery, patients with a higher income, patients living in areas close to Seoul, and patients living in areas without a metropolitan city. The utilization of the five largest hospitals increased by 2 percentage points after the policy went into effect. Conclusions The utilization of tertiary hospitals in Seoul was concentrated among the five largest hospitals. Future research is necessary to identify the consequences of this utilization pattern
Genetic mutation spectrum of pantothenate kinase-associated neurodegeneration expanded by breakpoint sequencing in pantothenate kinase 2 gene
Abstract
Background
Neurodegeneration with brain iron accumulation describes a group of rare heterogeneous progressive neurodegenerative disorders characterized by excessive iron accumulation in the basal ganglia region. Pantothenate kinase-associated neurodegeneration (PKAN) is a major form of this disease.
Results
A total of 7 unrelated patients were diagnosed with PKAN in a single tertiary center from August 2009 to February 2018. Ten variants in PANK2 including three novel sequence variants and one large exonic deletion were detected. Sequencing of the breakpoint was performed to predict the mechanism of large deletion and AluSx3 and AluSz6 were found with approximately 97.3% sequence homology.
Conclusion
The findings support the disease-causing role of PANK2 and indicate the possibility that exonic deletion of PANK2 found in PKAN is mediated through Alu-mediated homologous recombination
Trends in Inequality in Cigarette Smoking Prevalence by Income According to Recent Anti-smoking Policies in Korea: Use of Three National Surveys
Objectives This study examined trends in inequality in cigarette smoking prevalence by income according to recent anti-smoking policies in Korea. Methods The data used in this study were drawn from three nationally representative surveys, the Korea National Health and Nutrition Examination Survey, the Korea Community Health Survey, and the Social Survey of Statistics Korea. We calculated the age-standardized smoking prevalence, the slope index of inequality, and the relative index of inequality by income level as a socioeconomic position indicator. Results Smoking prevalence among men decreased during the study period, but the downward trend became especially pronounced in 2015, when the tobacco price was substantially increased. Inequalities in cigarette smoking by income were evident in both genders over the study period in all three national surveys examined. Absolute inequality tended to decrease between 2014 and 2015 among men. Absolute and relative inequality by income decreased between 2008 and 2016 in women aged 30-59, except between 2014 and 2015. Conclusions The recent anti-smoking policies in Korea resulted in a downward trend in smoking prevalence among men, but not in relative inequality, throughout the study period. Absolute inequality decreased over the study period among men aged 30-59. A more aggressive tax policy is warranted to further reduce socioeconomic inequalities in smoking in young adults in Korea
Study on a model of street vended food choices by Korean high school students
Street vended food (SVF) includes food and beverages prepared and sold outdoors or in public areas by street merchants for consumption on the scene or later without further preparation. Due to its low price and convenience, SVF has been popular in Korea for a long time, particularly with high school students. Beyond Korea, SVF is also popular in southeast Asia and southern Africa in the form of ready-to-eat food. This study on high school students, who are main consumers of SVF in Korea, focused on the factors that affect consumer loyalty. The study was performed by questionnaire and used AMOS software to develop a structural equation model. The results of verifying the model's fidelity were Ï2 = 685.989, df = 261, GFI = 0.851, AGFI = 0.814, NFI = 0.901, CFI = 0.907, RMR = 0.048, indicating a satisfying structural model. SVF quality and service, emotional response, and the physical environment had a statistically significant effect on consumer loyalty. In contrast, SVF sanitation had no statistically significant effect on consumer loyalty. Based on these results, the sanitary management of SVF needs to be addressed immediately combined with education for SVF providers to maintain a clean environment
Selective Growth of Layered Perovskites for Stable and Efficient Photovoltaics
Perovskite solar cells (PSCs) are promising alternatives toward clean energy because of their high-power
conversion efficiency (PCE) and low materials and processing cost. However, their poor stability under
operation still limits their practical applications. Here we design an innovative approach to control the
surface growth of a low dimensional perovskite layer on top of a bulk three-dimensional (3D) perovskite
film. This results in a structured perovskite interface where a distinct layered low dimensional perovskite
is engineered on top of the 3D film. Structural and optical properties of the stack are investigated and
solar cells are realized. When embodying the low dimensional perovskite layer, the photovoltaic cells
exhibit an enhanced PCE of 20.1% on average, when compared to pristine 3D perovskite. In addition,
superior stability is observed: the devices retain 85% of the initial PCE stressed under one sun illumination
for 800 hours at 50
1
C in an ambient environment
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