• Korean Journal of Soil Science and Fertilizer
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• 제21권4호
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• pp.386-408
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• 1988

A study was conducted to develop a model for estimating evapotranspiration and yield of Chinese cabbages from meteorological factors from 1981 to 1986 in Suweon, Korea. Lysimeters with water table maintained at 50cm depth were used to measure the potential evapotranspiration and the maximum evapotranspiration in situ. The actual evapotranspiration and the yield were measured in the field plots irrigated with different soil moisture regimes of -0.2, -0.5, and -1.0 bars, respectively. The soil water content throughout the profile was monitored by a neutron moisture depth gauge and the soil water potentials were measured using gypsum block and tensiometer. The fresh weight of Chinese cabbages at harvest was measured as yield. The data collected in situ were analyzed to obtain parameters related to modeling. The results were summarized as followings: 1. The 5-year mean of potential evapotranspiration (PET) gradually increased from 2.38 mm/day in early April to 3.98 mm/day in mid-June, and thereafter, decreased to 1.06 mm/day in mid-November. The estimated PET by Penman, Radiation or Blanney-Criddle methods were overestimated in comparison with the measured PET, while those by Pan-evaporation method were underestimated. The correlation between the estimated and the measured PET, however, showed high significance except for July and August by Blanney-Criddle method, which implied that the coefficients should be adjusted to the Korean conditions. 2. The meteorological factors which showed hgih correlation with the measured PET were temperature, vapour pressure deficit, sunshine hours, solar radiation and pan-evaporation. Several multiple regression equations using meteorological factors were formulated to estimate PET. The equation with pan-evaporation (Eo) was the simplest but highly accurate. PET = 0.712 + 0.705Eo 3. The crop coefficient of Chinese cabbages (Kc), the ratio of the maximum evapotranspiration (ETm) to PET, ranged from 0.5 to 0.7 at early growth stage and from 0.9 to 1.2 at mid and late growth stages. The regression equation with respect to the growth progress degree (G), ranging from 0.0 at transplanting day to 1.0 at the harvesting day, were: $$Kc=0.598+0.959G-0.501G^2$$ for spring cabbages $$Kc=0.402+1.887G-1.432G^2$$ for autumn cabbages 4. The soil factor (Kf), the ratio of the actual evapotranspiration to the maximum evapotranspiration, showed 1.0 when the available soil water fraction (f) was higher than a threshold value (fp) and decreased linearly with decreasing f below fp. The relationships were: Kf=1.0 for $$f{\geq}fp$$ Kf=a+bf for f$$I{\leq}Esm$$ Es = Esm for I > Esm 6. The model for estimating actual evapotranspiration (ETa) was based on the water balance neglecting capillary rise as: ETa=PET. Kc. Kf+Es 7. The model for estimating relative yield (Y/Ym) was selected among the regression equations with the measured ETa as: Y/Ym=a+bln(ETa) The coefficients and b were 0.07 and 0.73 for spring Chinese cabbages and 0.37 and 0.66 for autumn Chinese cabbages, respectively. 8. The estimated ETa and Y/Ym were compared with the measured values to verify the model established above. The estimated ETa showed disparities within 0.29mm/day for spring Chinese cabbages and 0.19mm/day for autumn Chinese cabbages. The average deviation of the estimated relative yield were 0.14 and 0.09, respectively. 9. The deviations between the estimated values by the model and the actual values obtained from three cropping field experiments after the completion of the model calibration were within reasonable confidence range. Therefore, this model was validated to be used in practical purpose.

• Journal of Chest Surgery
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• 제32권7호
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• pp.637-647
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• 1999

Background: Ischemia-reperfusion injury is one of the major contributing causes of early graft failure in lung transplantation. It has been suggested that triiodothyronine (T3) may ameliorate ischemia-reperfusion injury to various organs in vivo and in vitro. Predicting its beneficial effect for ischemic lung injury, we set out to demonstrate it by administering T3 into the in situ canine ischemia-reperfusion model. Material and Method: Sixteen adult mongrel dogs were randomly allocated into group A and B. T3 $(3.6\mug/kg)$ was administered before the initiation of single lung ischemia in group B, whereas the same amount of saline was administered in group A. Ischemia was induced in the left lung by clamping the left hilum for 100 minutes. After reperfusion, various hemodynamic parameters and blood gases were analyzed for 4 hours while intermittently clamping the right hilum in order to allow observation of the injured left lung function. Result: Arterial oxygen partial pressure $(PaO_2)$ decreased 30 minutes after reperfusion and recovered gradually thereafter in both groups. In group B the decrease of $PaO_2$ was less marked than in group A. The recovery of $PaO_2$ was faster in group B than in group A. The differences between the two groups were statistically significant from 30 minutes after reperfusion $(125\pm34$ mmHg and $252\pm44$ mmHg, p<0.05) until the end of the experiment $(178\pm42$mmHg and $330\pm37$ mmHg, p<0.05). The differences in the arterial carbon dioxide pressure, airway pressure and lung compliance showed no statistical significance. The malondialdehyde (MDA) level, measured from the tissue obtained 240 minutes after reperfusion, was lower in group B $(0.40\pm0.04\mu$M) than in group A $(0.53\pm0.05\mu$M, p<0.05). The ATP level of group B $(0.69\pm0.07\mu$M/g) was significantly higher than that of group A $(0.48\pm0.07\mu$M/g, p<0.05). The microscopic exami nation revealed varying degrees of injury such as perivascular neutrophil infiltration, capillary hemorrhage and interstitial congestion. There were no differences in the microscopic findings between the two groups. CONCLUSION T3 has beneficial effects on the ischemic canine lung injury including preservation of oxygenation capacity, less production of lipid peroxidation products and a higher level of tissue ATP. These results suggest that T3 is effective in pulmonary allograft preservation.

• Geophysics and Geophysical Exploration
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• 제13권1호
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• pp.80-87
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• 2010

This study was conducted to develop a reservoir modelling workflow to reproduce the heterogeneous distribution of effective permeability that impacts on the performance of SAGD (Steam Assisted Gravity Drainage), the in-situ bitumen recovery technique in the Athabasca Oil Sands. Lithologic facies distribution is the main cause of the heterogeneity in bitumen reservoirs in the study area. The target formation consists of sand with mudstone facies in a fluvial-to-estuary channel system, where the mudstone interrupts fluid flow and reduces effective permeability. In this study, the lithologic facies is classified into three classes having different characteristics of effective permeability, depending on the shapes of mudstones. The reservoir modelling workflow of this study consists of two main modules; facies modelling and permeability modelling. The facies modelling provides an identification of the three lithologic facies, using a stochastic approach, which mainly control the effective permeability. The permeability modelling populates mudstone volume fraction first, then transforms it into effective permeability. A series of flow simulations applied to mini-models of the lithologic facies obtains the transformation functions of the mudstone volume fraction into the effective permeability. Seismic data contribute to the facies modelling via providing prior probability of facies, which is incorporated in the facies models by geostatistical techniques. In particular, this study employs a probabilistic neural network utilising multiple seismic attributes in facies prediction that improves the prior probability of facies. The result of using the improved prior probability in facies modelling is compared to the conventional method using a single seismic attribute to demonstrate the improvement in the facies discrimination. Using P-wave velocity in combination with density in the multiple seismic attributes is the essence of the improved facies discrimination. This paper also discusses sand matrix porosity that makes P-wave velocity differ between the different facies in the study area, where the sand matrix porosity is uniquely evaluated using log-derived porosity, P-wave velocity and photographically-predicted mudstone volume.

• Journal of Navigation and Port Research
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• 제40권6호
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• pp.441-450
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• 2016

A pilot scale biostimulation experiment was performed under field conditions to degrade organic pollutants and PAHs (Polycyclic Aromatic Compounds) in contaminated coastal sediment. During the experiment, the seawater temperature around the sediment varied from $16.5^{\circ}C$ to $21^{\circ}C$, while the sediment pH was stable at 8.4-8.5. The experiment was conducted over a one year period with a control group and a sample group with a applied biostimulant composed of acetate, sulfate, and nitrate. Chemical oxygen demand decreased 39% in the control group and 79% in the sample group. Volatile solids were reduced from 15 to 7 g/kg in the control group and 2.5 g/kg in the sample group. Out of the 2-, 3- ,4- ,5-, and 6-rings of the 16 vital PAHs, the compound including naphthalene (2-ring), took 2 months to degrade completely, while the degradation efficiency was 55.6% in the control group during the same period. In the case of the 3-ring and 4-ring PAHs, complete degradation in the sample and 46% - 100% degradation in control was observed after one year of the experiment. The 5-ring and 6-ring PAHs were degraded to about 77%-100% in the sample group and 26%-87% in the control group during the one year of the experiment. The study results show that biostimulation is a very effective method to improve the degradation rate of organic pollutants and PAHs (Polycyclic Aromatic Compounds) in contaminated coastal sediment.

• Tuberculosis and Respiratory Diseases
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• 제42권1호
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• pp.1-10
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• 1995

Background: It has been well known that bronchial asthma is a chronic inflammatory disorder. The "activation" of lymphocytes has a significant role in the pathogenesis of bronchial asthma. Among these lymphocytes, TH2-like rather than TH1-like lymphoytes are activated in the bronchial tissues from patients with atopic bronchial asthma. However, the difference of cytokines expression is not well documented between the atopic normal subjects and atopic asthmatics. Methods: Bronchial tissues were obtained from the tweleve atopic and non-atpoic asthmatics and tweleve atopic and non-atopic healthy subjects for in stiu hybridizatin of IL-2, IL-4, IL-5, and INF-$\gamma$. The probe of cytokines were tagged with digoxigenin by random priming method. Results: The infiltration of many inflammatory cells on submucosa and denuded epithelium were observed in the bronchial tissue from patients with bronchial asthma. The RNase-treated bronchial tissues did not have the brown signal on the tissue, but, RNasc-untreated bronchial tissues had the positive brown signal on the inflammatory cells under the basement membrane. The IL-2 positive signals were detected in 2 cases, IFN-$\gamma$ in 1 casc, IL-4 in 2 cases, IL-5 in 2 cases among 6 non-atopic healthy subjects. The atopic healthy subjects showed 1 case of positive signal of IL-2 and IFN-$\gamma$, but did not show any signals of IL-4 and IL-5. The positive signals of IL-2 were detected in 4 cases among 6 atopic and 6 non-atopic asthmatics, 2 cases and 1 case of IFN-$\gamma$ respectively, 4 cases and 3 cases of IL-4 respectively, 4 cases and 3 cases of IL-5 respectively. Conclusion: The lymphocytes were activated in the bronchus of asthmatics. Among lymphocytes, TH2-like lymphocytes may be involved in the pathogenesis of bronchial asthma. However, futher study with immunohistochemical stain may be necessary for defining the source of cytokines, because of TH2-like lymphocytes were also activated in some atopic healthy subjects.

• Journal of Chest Surgery
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• 제38권10호
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• pp.685-692
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• 2005

Background: Wall motion abnormalities may be a significant predictor for long-term survival after coronary bypass surgery (CABG). The aim of this study is to see whether post-infarction wall motion abnormality of left ventricle affect on the long-term survival after CABG. Material and Method: One-hundred and thirty-three patients (male/female, 92/41) undergoing CABG more than 9 years ago were included in this study. Fifty-six patients (M/F, 42/14; mean age, $59.2\pm9.2$ years) with LV wall motion abnormalities were compared to 77 patients (M/F, 50/27; mean age, $58.0\pm7.6$ years) without the wall motion abnormalities. Most patients (112/133, $84.2\%$) had undergone on-pump CABG with the in-situ left internal thoracic artery and free grafts of saphenous vein, in which the proximal and distal anastomoses were done for the single aortic cross-clamping period. Result: Ejection fraction of left ventricle was lower in the group with LV wall motion abnormalities (mean ejection fraction, $48.7\pm13.2\%$) compared to the group without wall motion abnormalities (mean ejection fraction, $57.1\pm10.1\%$)(p=0.0001). Risk­unadjusted survivals after CABG in the group without wall motion abnormalities were $85.7\pm4.0\%,\;76.2\pm4.9\%,\;and\;57.2\pm10.3\%$ at 5, 10, and 13 years, respectively, and in the group with wall motion abnormalities were $80.4\pm5.3\%,\;58.7\pm7.3\%,\;and\;51.9\pm7.9\%$ at 5, 10, and 13 years, respectively (p=0.1). In univariate analysis, predictable factors of long-term survival in the patients with LV wall motion abnormalities were LV ejection fraction and post operative outpatient treatment. In multivariate analysis, predictable factor of long-term survival in the patients with the wall motion abnormalities was postoperative outpatient treatment, and that in those without the wall motion abnormalities was female. Conclusion: Although there was no significant survival difference after CABG between the group with LV wall motion abnormalities and that without wall motion abnormalities, the survival in the group with wall motion abnormalities seems to be more decreased. For the patients with LV wall motion abnormalities after myocardial infarction, the post-CABG outpatient treatment is suggested to be an important factor for the long-term survival.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제5권1호
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• pp.1-10
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• 2002

Purpose; Dysregulation of gastric epithelial cell proliferation and apoptosis are important in development of ulcer, atrophy and neoplasia in Helicobacter pylori (H. pylori) infection. The aim of this study was to investigate the effect of infection of H. pylori on gastric epithelial cell proliferation and apoptosis in children. Methods: Histological grading by updated Sydney system, PCNA immunostaining and TUNEL method were performed in H. pylori positive (N=58) and negative (N=40) gastric biopsy specimens. Results: In H. pylori positive children, there were significantly higher grade of polymorphonuclear neutrophil activity (P=0.000), chronic inflammation (P=0.000), epithelial damage (P=0.000) and lymphoid follicles (P=0.000) than in H. pylori negative children. Intestinal metaplasia was not seen in H. pylori positive children. PCNA index was significantly different between H. pylori positive children ($67.8{\pm}18.13$) and H. pylori negative children ($54.8{\pm}14.46$, P=0.000). There was positive correlation between PCNA index and H. pylori density (r=0.277, P=0.007), polymorphonuclear neutrophil activity (r=0.280, P=0.007) and chronic inflammation (r=0.284, P=0.006). Apoptosis index of H. pylori positive children ($0.44{\pm}0.447$) was significantly higher than of H. pylori negative children ($0.14{\pm}0.196$, P=0.000). There was positive correlation between apoptosis index and H. pylori density (r=0.472, P=0.000), polymorphonuclear neutrophil activity (r=0.370, P=0.001) and chronic inflammation (r=0.483, P=0.000). There was positive correlation between PCNA index and apoptosis index (r=0.353, P=0.003). Conclusion: The PCNA and apoptosis index in H. pylori positive children were significantly higher than in H. pylori negative children. This study suggested that gastric epithelial cell proliferation and apoptosis are important to pathogenesis of H. pylori infection in children.

• Journal of the Korean Geotechnical Society
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• 제15권4호
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• pp.113-132
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• 1999

Recently in Korea, application of the soil nailing is gradually extended to the sites of excavations and slopes having various ground conditions and field characteristics. Design of the soil nailing is generally carried out in two steps, The First step is to examine the minimum safety factor against a sliding of the reinforced nailed-soil mass based on the limit equilibrium approach, and the second step is to check the maximum displacement expected to occur at facing using the numerical analysis technique. However, design parameters related to the soil nailing system are so various that a reliable design method considering interrelationships between these design parameters is continuously necessary. Additionally, taking into account the anisotropic characteristics of in-situ grounds, disturbances in collecting the soil samples and errors in measurements, a systematic analysis of the field measurement data as well as a rational technique of the optimum design is required to improve with respect to economical efficiency. As a part of these purposes, in the present study, a procedure for the optimum design of a soil nailing excavation wall system is proposed. Focusing on a minimization of the expenses in construction, the optimum design procedure is formulated based on the genetic algorithm. Neural network theory is further adopted in predicting the maximum horizontal displacement at a shotcrete facing. Using the proposed procedure, various effects of relevant design parameters are also analyzed. Finally, an optimized design section is compared with the existing design section at the excavation site being constructed, in order to verify a validity of the proposed procedure.

• Korean Journal of Remote Sensing
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• 제36권2_2호
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• pp.249-261
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• 2020

Coastal monitoring using multiple platforms/sensors is a very important tools for accurately understanding the changes in offshore marine environment and disaster with high temporal and spatial resolutions. However, integrated observation studies using multiple platforms and sensors are insufficient, and none of them have been evaluated for efficiency and limitation of convergence. In this study, we aimed to suggest an integrated observation method with multi-remote sensing platform and sensors, and to diagnose the utility and limitation. Integrated in situ surveys were conducted using Rhodamine WT fluorescent dye to simulate various marine disasters. In September 2019, the distribution and movement of RWT dye patches were detected using satellite (Kompsat-2/3/3A, Landsat-8 OLI, Sentinel-3 OLCI and GOCI), unmanned aircraft (Mavic 2 pro and Inspire 2), and manned aircraft platforms after injecting fluorescent dye into the waters of the South Sea-Yeosu Sea. The initial patch size of the RWT dye was 2,600 ㎡ and spread to 62,000 ㎡ about 138 minutes later. The RWT patches gradually moved southwestward from the point where they were first released,similar to the pattern of tidal current flowing southwest as the tides gradually decreased. Unmanned Aerial Vehicles (UAVs) image showed highest resolution in terms of spatial and time resolution, but the coverage area was the narrowest. In the case of satellite images, the coverage area was wide, but there were some limitations compared to other platforms in terms of operability due to the long cycle of revisiting. For Sentinel-3 OLCI and GOCI, the spectral resolution and signal-to-noise ratio (SNR) were the highest, but small fluorescent dye detection was limited in terms of spatial resolution. In the case of hyperspectral sensor mounted on manned aircraft, the spectral resolution was the highest, but this was also somewhat limited in terms of operability. From this simulation approach, multi-platform integrated observation was able to confirm that time,space and spectral resolution could be significantly improved. In the future, if this study results are linked to coastal numerical models, it will be possible to predict the transport and diffusion of contaminants, and it is expected that it can contribute to improving model accuracy by using them as input and verification data of the numerical models.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• 제13권1호
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• pp.42-55
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• 2008

To evaluate the accuracy of currents measured by HF radar in the coastal sea off Keum River estuary, we compared the facing radial vectors of two HF radars, and HF radar-derived currents with in-situ measurement currents. Principal component analysis was used to extract regression line and RMS deviation in the comparison. When two facing radar's radial vectors at the mid-point of baseline are compared, RMS deviation is 4.4 cm/s in winter and 5.4 cm/s in summer. When GDOP(Geometric Dilution of Precision) effect is corrected from the RMS deviations that is analyzed from the comparison between HF radar-derived and current-metermeasured currents, the error of velocity combined by HF radar-derived current is less than 5.1 cm/s in the stations having moderate GDOP values. These two results obtained from different method suggest that the lower limit of HF radar-derived current's accuracy is 5.4 cm/s in our study area. As mentioned in previous researches, RMS deviations become large in the stations located near the islands and increase as a function of mean distance from the radar site due to decrease of signal-to-noise level and the intersect angle of radial vectors. We found that an uncertain error bound of HF radar-derived current can be produced from the separation process of RMS deviations using GDOP value if GDOP value for each component is very close and RMS deviations obtained from current component comparison are also close. When the current measured in the stations having moderate GDOP values is separated into tidal and subtidal current, characteristics of tidal current ellipses analyzed from HF radar-derived current show a good agreement with those from current-meter-measured current, and time variation of subtidal current showed a response reflecting physical process driven by wind and density field.