1,604 research outputs found
Non-Iterative Tone Mapping With High Efficiency and Robustness
This paper proposes an efficient approach for tone mapping, which provides a high perceptual image quality for diverse scenes. Most existing methods, optimizing images for the perceptual model, use an iterative process and this process is time consuming. To solve this problem, we proposed a new layer-based non-iterative approach to finding an optimal detail layer for generating a tone-mapped image. The proposed method consists of the following three steps. First, an image is decomposed into a base layer and a detail layer to separate the illumination and detail components. Next, the base layer is globally compressed by applying the statistical naturalness model based on the statistics of the luminance and contrast in the natural scenes. The detail layer is locally optimized based on the structure fidelity measure, representing the degree of local structural detail preservation. Finally, the proposed method constructs the final tone-mapped image by combining the resultant layers. The performance evaluation reveals that the proposed method outperforms the benchmarking methods for almost all the benchmarking test images. Specifically, the proposed method improves an average tone mapping quality index-II (TMQI-II), a feature similarity index for tone-mapped images (FSITM), and a high-dynamic range-visible difference predictor (HDR-VDP)-2.2 by up to 0.651 (223.4%), 0.088 (11.5%), and 10.371 (25.2%), respectively, compared with the benchmarking methods, whereas it improves the processing speed by over 2611 times. Furthermore, the proposed method decreases the standard deviations of TMQI-II, FSITM, and HDR-VDP-2.2, and processing time by up to 81.4%, 18.9%, 12.6%, and 99.9%, respectively, when compared with the benchmarking methods.11Ysciescopu
The Risk of Stress Urinary Incontinence After Hysterectomy for Uterine Fibroids
Purpose We evaluated the relationship between previous hysterectomy for uterine fibroids and subsequent stress urinary incontinence (SUI). Methods This study analyzed national health insurance data. The hysterectomy group (aged 40 to 59) comprised patients who underwent hysterectomy for uterine fibroids between January 1, 2011 and December 31, 2014, and the control group (aged 40 to 59) comprised patients who visited a medical facility for a checkup during the same time span. One-to-one propensity score matching was performed to balance confounders. SUI was defined as the need for SUI surgery accompanied by a diagnosis code for SUI. Results After matching, 81,373 cases (hysterectomy group) and 81,373 controls (nonhysterectomy group) were enrolled. The mean follow-up period was 7.9 years for the cases and 7.8 years for the controls. The incidence of anti-incontinence surgery was slightly but significantly higher in the cases than in the controls (2.0% vs. 1.7%, P<0.001). Compared to the control group, abdominal hysterectomy significantly increased the likelihood of anti-incontinence surgery both before (hazard ratio [HR], 1.235; 95% confidence interval [CI], 1.116–1.365) and after adjusting for confounders (HR, 1.215; 95% CI, 1.097–1.347). In contrast, laparoscopic hysterectomy, laparoscopic hysterectomy with adnexal surgery, and abdominal hysterectomy with adnexal surgery were not associated with an increased rate of anti-incontinence surgery. The significant association between abdominal hysterectomy and an elevated rate of anti-incontinence surgery persisted even after stratifying patients by age group. Conclusions Prior abdominal hysterectomy without adnexal surgery was associated with an increased incidence of subsequent anti-urinary incontinence surgery
Generation of a single-cycle pulse using a two-stage compressor and its temporal characterization using a tunnelling ionization method
A single-cycle laser pulse was generated using a two-stage compressor and characterized using a pulse characterization technique based on tunnelling ionization. A 25-fs, 800-nm laser pulse was compressed to 5.5 fs using a gas-filled hollow-core fibre and a set of chirped mirrors. The laser pulse was further compressed, down to the single-cycle limit by propagation through multiple fused-silica plates and another set of chirped mirrors. The two-stage compressor mitigates the development of higher-order dispersion during spectral broadening. Thus, a single-cycle pulse was generated by compensating the second-order dispersion using chirped mirrors. The duration of the single-cycle pulse was 2.5 fs, while its transform-limited duration was 2.2 fs. A continuum extreme ultraviolet spectrum was obtained through high-harmonic generation without applying any temporal gating technique. The continuum spectrum was shown to have a strong dependence on the carrier-envelope phase of the laser pulse, confirming the generation of a single-cycle pulse. © 2019, The Author(s
Application and evaluation of the MLVA typing assay for the Brucella abortus strains isolated in Korea
<p>Abstract</p> <p>Background</p> <p>A Brucella eradication program has been executed in Korea. To effectively prevent and control brucellosis, a molecular method for genetic identification and epidemiological trace-back must be established. As part of that, the MLVA typing assay was evaluated and applied to <it>B. abortus </it>isolates for analyzing the characteristics of the regional distribution and relationships of foreign isolates.</p> <p>Results</p> <p>A total of 177 isolates originating from 105 cattle farms for the period 1996 to 2008 were selected as representatives for the nine provinces of South Korea. A dendrogram of strain relatedness was constructed in accordance with the number of tandem repeat units for 17 loci so that it was possible to trace back in the restricted areas. Even in a farm contaminated by one source, however, the <it>Brucella </it>isolates showed an increase or decrease in one TRs copy number at some loci with high DI values. Moreover, those 17 loci was confirmed in stability via <it>in-vitro </it>and <it>in-vivo </it>passage, and found to be sufficiently stable markers that can readily identify the inoculated strain even if minor changes were detected. In the parsimony analysis with foreign <it>Brucella </it>isolates, domestic isolates were clustered distinctively, and located near the Central and Southern American isolates.</p> <p>Conclusion</p> <p>The MLVA assay has enough discrimination power in the <it>Brucella </it>species level and can be utilized as a tool for the epidemiological trace-back of the <it>B. abortus </it>isolates. But it is important to consider that <it>Brucella </it>isolates may be capable of undergoing minor changes at some loci in the course of infection or in accordance with the changes of the host.</p
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