232 research outputs found

    State Complexity of Regular Tree Languages for Tree Matching

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    We study the state complexity of regular tree languages for tree matching problem. Given a tree t and a set of pattern trees L, we can decide whether or not there exists a subtree occurrence of trees in L from the tree t by considering the new language L′ which accepts all trees containing trees in L as subtrees. We consider the case when we are given a set of pattern trees as a regular tree language and investigate the state complexity. Based on the sequential and parallel tree concatenation, we define three types of tree languages for deciding the existence of different types of subtree occurrences. We also study the deterministic top-down state complexity of path-closed languages for the same problem.</jats:p

    Case study on high-resolution monitoring network of groundwater heat pump system

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    With the increasing installation of shallow geothermal energy, the importance of thermal impact prediction also increases in the system design stage. In nature, it is general that heterogeneity exists and it can affect the groundwater flow as well as the transport along to the flow. When predicting heat transport under the groundwater heat pump (GWHP) operation, however, impacts of heterogeneity have rarely been considered. In this study, to detect the hydraulic and thermal feedback to the two months of GWHP operation, a dense monitoring network was constructed with 12 monitoring wells at Eumseong-gun, Republic of Korea. The temperature was monitored in high resolution via fiber-optic distributed temperature sensing. During the GWHP operation, a very dynamic flow condition was generated with the hydraulic gradient between 0.005 and 0.07. The maximum temperature change at the nearest monitoring well was 2 ?. Observed hydraulic and thermal responses showed spatially heterogeneous results. While the heterogeneous responses of hydraulic change were stronger near the geothermal wells, those of temperature change were higher near the center of the thermal plume

    Factors Affecting the Designation of Cerebrovascular Diseases as Work-Related in Administrative Litigation

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    The purpose of this study was to identify factors that could be used as standardized criteria for evaluating occupational diseases in initial assessments or requests for examination. Using 100 administrative litigation cases on the work-relatedness of cerebrovascular diseases (CVDs) by the Seoul Branch of the Korea Labor Welfare Corporation (KLWC) from 1997 to 2002, we estimated the relationship between the investigated variables and designation of the work-relatedness of the CVD. As for the age, the odds ratio of the acceptance rate of a case as work-related in subjects over 60 yr of age was 0.08 (95% CI, 0.01-0.75), which was compared to subjects under 30 yr of age. Regarding working hours, the odds ratio of the acceptance rate of a case as work-related in CVDs in those over 56 hr was 9.50 (95% CI, 1.92-47.10) when compared to those less than 56 hr. As for the benefit type, the odds ratio of the acceptance rate of a case as work-related in medical benefits was 5.74 (95% CI, 1.29-25.54), compared to survivor benefits. As for the criteria for defining situations as work overload, the odds ratio of the acceptance rate of a case as work-related in injured workers was 12.06 (95% CI, 3.12-46.62), compared to that in non-injured workers. Our findings show that the criteria for defining situations of work overload played an important role in assessing the work-relatedness of CVDs in administrative litigation, and it is necessary to make the scientific evidence on judgement of work-relatedness on overwork

    Hierarchical Micro/Nano-Porous Acupuncture Needles Offering Enhanced Therapeutic Properties

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    Acupuncture as a therapeutic intervention has been widely used for treatment of many pathophysiological disorders. For achieving improved therapeutic effects, relatively thick acupuncture needles have been frequently used in clinical practice with, in turn, enhanced stimulation intensity. However due to the discomforting nature of the larger-diameter acupuncture needles there is considerable interest in developing advanced acupuncture therapeutical techniques that provide more comfort with improved efficacy. So motivated, we have developed a new class of acupuncture needles, porous acupuncture needles (PANs) with hierarchical micro/nano-scale conical pores upon the surface, fabricated via a simple and well known electrochemical process, with surface area approximately 20 times greater than conventional acupuncture needles. The performance of these high-surface-area PANs is evaluated by monitoring the electrophysiological and behavioral responses from the in vivo stimulation of Shenmen (HT7) points in Wistar rats, showing PANs to be more effective in controlling electrophysiological and behavioral responses than conventional acupuncture needles. Comparative analysis of cocaine induced locomotor activity using PANs and thick acupuncture needles shows enhanced performance of PANs with significantly less pain sensation. Our work offers a unique pathway for achieving a comfortable and improved acupuncture therapeutic effect. © The Author(s) 2016.1

    Attributable fraction of alcohol consumption on cancer using population-based nationwide cancer incidence and mortality data in the Republic of Korea

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    BACKGROUND: In the Republic of Korea, cancer is the most common cause of death, and cancer incidence and mortality rates are the highest in East Asia. As alcoholic beverages are carcinogenic to humans, we estimated the burden of cancer related to alcohol consumption in the Korean population. METHODS: The cancer sites studied were those for which there is convincing evidence of a positive association with alcohol consumption: oral cavity, pharynx, esophagus, colon, rectum, liver, larynx and female breast. Sex- and cancer-specific population attributable fractions (PAF) were calculated based on: 1) the prevalence of alcohol drinkers among adults ≥ 20 years of age in 1989; 2) the average daily alcohol consumption (g/day) among drinkers in 1998; 3) relative risk (RR) estimates for the association between alcohol consumption and site-specific cancer incidence obtained either from a large Korean cohort study or, when more than one Korean study was available for a specific cancer site, meta-analyses were performed and the resulting meta-RRs were used; 4) national cancer incidence and mortality data from 2009. RESULTS: Among men, 3% (2,866 cases) of incident cancer cases and 2.8% (1,234 deaths) of cancer deaths were attributable to alcohol consumption. Among women, 0.5% (464 cancer cases) of incident cancers and 0.1% (32 deaths) of cancer deaths were attributable to alcohol consumption. In particular, the PAF for alcohol consumption in relation to oral cavity cancer incidence among Korean men was 29.3%, and the PAFs for pharyngeal and laryngeal cancer incidence were 43.3% and 25.8%, respectively. Among Korean women, the PAF for colorectal cancer incidence was the highest (4.2%) and that for breast cancer incidence was only 0.2%. Avoiding alcohol consumption, or reducing it from the median of the highest 4th quartile of consumption (56.0 g/day for men, 28.0 g/day for women) to the median of the lowest quartile (2.80 g/day for men, 0.80 g/day for women), would reduce the burden of alcohol-related cancers in Korea. CONCLUSIONS: A reduction in alcohol consumption would decrease the cancer burden and a significant impact is anticipated specifically for the cancers oral cavity, pharynx, and larynx among men in the Republic of Korea

    Suppressive Effect on Lipopolysaccharide-Induced Proinflammatory Mediators by Citrus aurantium L. in Macrophage RAW 264.7 Cells via NF-κB Signal Pathway

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    Citrus fruits have been used as an edible fruit and a traditional medicine since ancient times. In particular, the peels of immature citrus fruits are used widely in traditional herbal medicine in Korea, as they are believed to contain bioactive components exerting anti-inflammatory activity. This study examined whether the crude methanol extract of Citrus aurantium L. (CME) has a suppressive effect on inducible enzymes and proinflammatory cytokines by inhibiting the NF-κB pathway in LPS-stimulated macrophage RAW 264.7 cells. The cells were pretreated with the indicated concentrations of CME (5, 10, 20, and 50 μg/mL) and then treated with LPS (1 μg/mL). The results showed that CME (10, 20, and 50 μg/mL) inhibited the LPS- (1 μg/mL) induced mRNA and protein expression of iNOS in macrophage Raw 264.7 cells. In addition, the expression of COX-2 was inhibited at the mRNA and protein levels by CME in a dose-dependent manner. The mRNA expression of proinflammatory cytokines, such as TNF-α and IL-6, were markedly reduced by CME (10, 20, and 50 μg/mL). Moreover, CME clearly suppressed the nuclear translocation of the NF-κB p65 subunits, which was correlated with its inhibitory effect on I-κB phosphorylation. These results suggest that CME has anti-inflammatory properties by modulating the expression of COX-2, iNOS, and proinflammatory cytokines, such as TNF-α and IL-6, in macrophage RAW 264.7 cells via the NF-κB pathway

    Population-attributable causes of cancer in Korea : obesity and physical inactivity

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    Changes in lifestyle including obesity epidemic and reduced physical activity influenced greatly to increase the cancer burden in Korea. The purpose of the current study was to perform a systematic assessment of cancers attributable to obesity and physical inactivity in Korea. Gender- and cancer site-specific population-attributable fractions (PAF) were estimated using the prevalence of overweight and obesity in 1992-1995 from a large-scale prospective cohort study, the prevalence of low physical activity in 1989 from a Korean National Health Examination Survey, and pooled relative risk estimates from Korean epidemiological studies. The overall PAF was then estimated using 2009 national cancer incidence data from the Korea Central Cancer Registry. Excess body weight was responsible for 1,444 (1.5%) and 2,004 (2.2%) cancer cases among men and women, respectively, in 2009 in Korea. Among men, 6.8% of colorectal, 2.9% of pancreatic, and 16.0% of kidney cancer was attributable to excess body weight. In women, 6.6% of colorectal, 3.9% of pancreatic, 18.7% of kidney, 8.2% of postmenopausal breast, and 32.7% of endometrial cancer was attributable to excess body weight. Low leisure-time physical activity accounted for 8.8% of breast cancer, whereas the PAF for overall cancer was low (0.1% in men, 1.4% in women). Projections suggest that cancers attributable to obesity will increase by 40% in men and 16% in women by 2020. With a significantly increasing overweight and physically inactive population, and increasing incidence of breast and colorectal cancers, Korea faces a large cancer burden attributable to these risk factors. Had the obese population of Korea remained stable, a large portion of obesity-related cancers could have been avoided. Efficient cancer prevention programs that aim to reduce obesity- and physical inactivity-related health problems are essential in Korea

    Optimizing Semi-Analytical Algorithms for Estimating Chlorophyll-a and Phycocyanin Concentrations in Inland Waters in Korea

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    Several semi-analytical algorithms have been developed to estimate the chlorophyll-a (Chl-a) and phycocyanin (PC) concentrations in inland waters. This study aimed at identifying the influence of algorithm parameters on the output variables and searching optimal parameter values. The optimal parameters of seven semi-analytical algorithms were applied to estimate the Chl-a and PC concentrations. The absorption coefficient measurements were coupled with pigment measurements to calibrate the algorithm parameters. For sensitivity analysis, the elementary effect test was conducted to analyze the influence of the algorithm parameters. The sensitivity analysis results showed that the parameters in the Y function and specific absorption coefficient were the most sensitive parameters. Then, the parameters were optimized via a single-objective optimization that involved one objective function being minimized and a multi-objective optimization that contained more than one objective function. The single-objective optimization led to substantial errors in absorption coefficients. In contrast, the multi-objective optimization improved the algorithm performance with respect to both the absorption coefficient estimates and pigment concentration estimates. The optimized parameters of the absorption coefficient reflected the high-particulate content in waters of the Baekje reservoir using an infrared backscattering wavelength and relatively high value of Y. Moreover, the results indicate the value of measuring the site-specific absorption if site-specific optimization of semi-analyical algorithm parameters was envisioned
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