875 research outputs found

    Real-Time Terrain Storage Generation from Multiple Sensors towards Mobile Robot Operation Interface

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    A mobile robot mounted with multiple sensors is used to rapidly collect 3D point clouds and video images so as to allow accurate terrain modeling. In this study, we develop a real-time terrain storage generation and representation system including a nonground point database (PDB), ground mesh database (MDB), and texture database (TDB). A voxel-based flag map is proposed for incrementally registering large-scale point clouds in a terrain model in real time. We quantize the 3D point clouds into 3D grids of the flag map as a comparative table in order to remove the redundant points. We integrate the large-scale 3D point clouds into a nonground PDB and a node-based terrain mesh using the CPU. Subsequently, we program a graphics processing unit (GPU) to generate the TDB by mapping the triangles in the terrain mesh onto the captured video images. Finally, we produce a nonground voxel map and a ground textured mesh as a terrain reconstruction result. Our proposed methods were tested in an outdoor environment. Our results show that the proposed system was able to rapidly generate terrain storage and provide high resolution terrain representation for mobile mapping services and a graphical user interface between remote operators and mobile robots

    Automated Space Classification for Network Robots in Ubiquitous Environments

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    Network robots provide services to users in smart spaces while being connected to ubiquitous instruments through wireless networks in ubiquitous environments. For more effective behavior planning of network robots, it is necessary to reduce the state space by recognizing a smart space as a set of spaces. This paper proposes a space classification algorithm based on automatic graph generation and naive Bayes classification. The proposed algorithm first filters spaces in order of priority using automatically generated graphs, thereby minimizing the number of tasks that need to be predefined by a human. The filtered spaces then induce the final space classification result using naive Bayes space classification. The results of experiments conducted using virtual agents in virtual environments indicate that the performance of the proposed algorithm is better than that of conventional naive Bayes space classification

    Transparent and conductive nanomembranes with orthogonal silver nanowire arrays for skin-attachable loudspeakers and microphones

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    We demonstrate ultrathin, transparent, and conductive hybrid nanomembranes (NMs) with nanoscale thickness, consisting of an orthogonal silver nanowire array embedded in a polymer matrix. Hybrid NMs significantly enhance the electrical and mechanical properties of ultrathin polymer NMs, which can be intimately attached to human skin. As a proof of concept, we present a skin-attachable NM loudspeaker, which exhibits a significant enhancement in thermoacoustic capabilities without any significant heat loss from the substrate. We also present a wearable transparent NM microphone combined with a micropyramid-patterned polydimethylsiloxane film, which provides excellent acoustic sensing capabilities based on a triboelectric voltage signal. Furthermore, the NM microphone can be used to provide a user interface for a personal voice-based security system in that it can accurately recognize a user???s voice. This study addressed the NM-based conformal electronics required for acoustic device platforms, which could be further expanded for application to conformal wearable sensors and health care devices

    Dissolution behaviors of PuO2(cr) in natural waters

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    PuO2(cr) dissolution in natural water was investigated at 25°C and 60°C under atmospheric conditions. The concentration of Pu in solutions [Pu], was monitored for 1 year of reaction time. PuO2(cr) dissolution in natural water reached a steady state within 2 months at 25°C. The [Pu] in groundwater and seawater at pH 8 were in the range of [Pu] = 0.9–34 and 3.4–27 nM, respectively. The [Pu] in concrete porewater (rainwater equilibrated with concrete) at pH 8.1–10.9 was in the range of 0.1–3.2 nM. The [Pu] and pH values of groundwater were similar to those of seawater samples having a high ionic strength. The measured [Pu] at equilibrium in all samples was higher than the calculated solubility curves for PuO2(am, hyd). Experimental evidence is insufficient to confirm the oxidation state of Pu in solution and solid phases. However, the results of geochemical modeling indicate that PuO2(am, hyd) and aqueous Pu(IV) species are dominant in natural water samples of this work. The dissolution behavior of PuO2(cr) in natural waters is comparable to the oxidative dissolution of PuO2(am, hyd) in the presence of PuO2(coll, hyd). The dissolution of PuO2 in groundwater decreased at higher temperatures, whereas the influence of temperature in seawater and porewater was not significant under these experimental conditions

    The Epidemiology of Diabetes in Korea

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    Diabetes is an increasing global health problem worldwide. Diabetes and its complications have become a major cause of morbidity and mortality in Korea. The prevalence of diabetes in Korea has increased six- to seven-fold from 1.5% to 9.9% in the past 40 years. The prevalence of impaired fasting glucose also increased to about 20% in 2009. The International Diabetes Federation has estimated that the prevalence of diabetes will rise to 11.4% in 2030. Possible risk factors for diabetes in Korea are age, male gender, obesity, prediabetes, gestational diabetes, smoking, decreased physical activity, and short sleep duration. With increasing obesity, especially in childhood, and improved longevity, the prevalence of diabetes is expected to dramatically increase more than previously estimated. Therefore, public efforts to introduce healthy lifestyle changes and diabetic prevention programs are necessary to reduce the global epidemic of diabetes

    Sleep Duration, Sleep Quality, and the Development of Nonalcoholic Fatty Liver Disease:A Cohort Study

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    INTRODUCTION: The longitudinal relationship between sleep duration, sleep quality, and the risk of nonalcoholic fatty liver disease (NAFLD) is unknown. We aimed to examine the association between sleep duration, sleep quality, and NAFLD development.METHODS: Using the Pittsburgh Sleep Quality Index, sleep duration and quality were evaluated for 143,306 NAFLD-free Korean adults with a mean age of 36.6 years, who were followed for an average of 4.0 years. Hepatic steatosis (HS) was assessed using ultrasonography and liver fibrosis by the fibrosis-4 index (FIB-4) or the NAFLD fibrosis score. Flexible parametric proportional hazard models were used to determine the hazard ratios (HRs) and 95% confidence intervals.RESULTS: There were 27,817 subjects with incident HS, of whom 1,471 had incident HS plus intermediate/high FIB-4. Multivariable-adjusted HRs (95% confidence intervals) for incident HS comparing sleep durations of ≤5, 6, 8, and ≥ 9 hours with 7 hours were 1.19 (1.14-1.23), 1.07 (1.04-1.10), 0.98 (0.94-1.02), and 0.95 (0.87-1.03), respectively. The corresponding HRs for incident HS plus intermediate/high FIB-4 were 1.30 (1.11-1.54), 1.14 (1.01-1.29), 1.11 (0.93-1.33), and 1.08 (0.71-1.63). The association between sleep duration and HS plus intermediate/high FIB-4 was inverse in individuals with good sleep quality but tended to be U-shaped in those with poor sleep quality. The results were similar if FIB-4 was replaced by the NAFLD fibrosis score.DISCUSSION: In young adults, short sleep duration was independently associated with an increased risk of incident NAFLD with or without intermediate/high fibrosis score, suggesting a role for inadequate sleep quantity in NAFLD risk and severity.</p

    Decrease in sleep duration and poor sleep quality over time is associated with an increased risk of incident non-alcoholic fatty liver disease

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    The impact of changes in sleep duration and sleep quality over time on the risk of nonalcoholic fatty liver disease (NAFLD) is not known. We investigated whether changes in sleep duration and in sleep quality between baseline and follow-up are associated with the risk of developing incident NAFLD. The cohort study included 86,530 Korean adults without NAFLD and with a low fibrosis score at baseline. The median follow-up was 3.6 years. Sleep duration and quality were assessed using the Pittsburgh Sleep Quality Index. Hepatic steatosis (HS) and liver fibrosis were assessed using ultrasonography and the fibrosis-4 index (FIB-4). Cox proportional hazard models were used to determine hazard ratios (HRs) and 95% confidence intervals (Cis). A total of 12,127 subjects with incident HS and 559 with incident HS plus intermediate/high FIB-4 was identified. Comparing the decrease in sleep duration of &gt;1 h, with stable sleep duration, the multivariate-adjusted HR (95% CIs) for incident HS was 1.24 (1.15–1.35). The corresponding HRs for incident HS plus intermediate/high FIB-4 was 1.58 (1.10–2.29). Comparing persistently poor sleep quality with persistently good sleep quality, the multivariate-adjusted HR for incident HS was 1.13 (95% CI, 1.05–1.20). A decrease in sleep duration or poor sleep quality over time was associated with an increased risk of incident NAFLD, underscoring an important potential role for good sleep in preventing NAFLD risk.</p

    Effect of grafting on growth and incidence of phytophthora blight and bacterial wilt of pepper (Capsicum annuum L.)

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    This study was conducted to investigate the effect of grafting using commercial rootstocks and breeding lines on growth and resistance to both Phytophthora blight (Phytophthora capsici) and bacterial wilt (Ralstonia solanacearum), and to evaluate the breeding lines as candidates rootstocks for grafted peppers. Capsicum annuum 'Nokkwang' (scion) was grafted onto five commercial rootstocks ('Kataguruma', 'Konesianhot', 'Koregon PR-380', 'PR-power', and 'Tantan') and nine breeding lines ('PR 901', 'PR 919', 'PR 920', 'PR 921', 'PR 922', 'PR 927', 'PR 928', 'PR 929', and 'PR 930'). Graft-take percentage was over 80% in all the grafted seedlings except those grafted onto 'PR 901' (75%). The number of leaves, stem diameter, leaf area, and dry weight of shoot of grafted seedlings were greater than those of non-grafted seedlings. Mineral contents in the shoots of grafted seedlings were significantly different, depending on rootstock genotypes. Marketable yield ranged from 1.35 to 1.96 kg per plant depending on rootstock genotypes, and was highest in peppers grafted onto 'PR 901' (1.95 kg) and non-grafted peppers (1.96 kg), and lowest in those grafted onto 'PR 928' (1.35 kg). Gross yield was highest in peppers grafted onto 'Konesianhot' (2.64 kg). Among nine breeding lines, three rootstocks ('PR 920', 'PR 921', and 'PR 922') were selected as candidate rootstocks for the grafted pepper based on graft-take, growth, yield, fruit quality, and resistance to diseases. Three major pepper cultivars ('Nokkwang', 'Saengsaeng Matkkwari', and 'Shinhong') were grafted onto those three breeding lines and 'Tantan' (control). Peppers grafted onto breeding lines of 'PR 920', 'PR 921', and 'PR 922' showed greater resistance to both Phytophthora blight and bacterial wilt without the decrease in yield and fruit quality. Accordingly, they were considered to be used as rootstocks resistant to both Phytophthora blight and bacterial wilt for pepper production.OAIID:oai:osos.snu.ac.kr:snu2012-01/102/0000027607/1SEQ:1PERF_CD:SNU2012-01EVAL_ITEM_CD:102USER_ID:0000027607ADJUST_YN:YEMP_ID:A075898DEPT_CD:517CITE_RATE:0FILENAME:2012-2-heb-접목-내병성-장윤아.pdfDEPT_NM:식물생산과학부EMAIL:[email protected]_YN:NCONFIRM:

    Single- and repeated-dose toxicities of aloe fermentation products in rats

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    In this study, aloe fermentation products were derived from mycelia from 3 mushrooms: Ganoderma lucidum (AG), Hericium erinaceum (AH), and Phellinus linteus (AP). Levels of aloin A and B increased with fermentation time. The highest levels were measured on the fifth day of fermentation. β-Glucan levels decreased with fermentation time. The safety of aloe fermentation products were examined in male and female Sprague-Dawley rats. Rats were orally administered the three aloe fermentation products at dose levels of 1, 2 or 5 g/kg for single-dose toxicity test and 0.5, 1, or 2 g/kg for repeated-dose toxicity test. There were no significant differences in body weight gain between vehicle control and AG-, AH- or AP-treated rats. Also, significant changes in daily feed intake and water consumption were not observed. In hematological analysis, none of the parameters were affected by aloe fermentation products with mushroom mycelia. This suggests that there are no negative effects on homeostasis and immunity. In blood biochemistry analysis, none of the markers were affected by feeding rats with AG, AH or AP. Similarly, there were no significant effects on markers for liver, kidney, skeletal and heart muscle functions. No remarkable lesions were observed in these organs at histopathology. Since there were no adverse effects of AG, AH and AP in single- or repeated-dose toxicity tests, even at higher doses than normal, we conclude that the aloe fermentation products with mushroom mycelia possess long-term safety and could be candidates as multifunctional nutrients for the improvement of intestinal function and immunity
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