• Journal of Chest Surgery
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• v.30 no.11
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• pp.1111-1116
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• 1997

In a period from Sep 1994 to Sep 1996, 38 patients were treated for spontaneous pneumothorax by video-assisted thoracic surgery(VATS). 31 male and 7 female patients with ages between 17 and 79(mean 30.0 years). No death occured. The postoperative complication rate of VATS was 7.9%(3/38). We noted no recurrence of pneumothorax, 3 wound dehiscence, 3 persistent air leak(>7days) in the patients. We compared theses results with thoracoscopic surgery of spontaneous pneumothorax in 38 cases(Group A), with cases of 21 patients(Group B) performed by the thoracotomy in the same period. There have been no recurrence in groud A, and one recurrence in group B at a median follow-up of 14.37$\pm$7.48 months and 16.81 $\pm$7.12 months, respectively. There was no significant difference in the duration of operation time including induction time between VATS and thoracotomy, but postoperative hospital stay and chest tube drainage periods were all less for these undergone VATS. Postoperative complication was less in group A(3/38=7.9%, 3 cases with persistent air leak >7days, all developed wound dehiscence, too), than in group B(9/21=42.9%, 8 cases with persistent air leak more than 7days, including 2 wound dehiscence, one recurrence, and the other one case of empyema). In our experience, VATS has the effectiveness of thoracic surgery for treating thoracic problems, has resulted in surgical intervention in spontaneous pneumothorax.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.4 s.23
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• pp.37-47
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• 2006

Urban development results in increased runoff volume and flowrates and shortening in time of concentration, which may cause frequent flooding downstream. Flow retardation structures to limit adverse downstream effects of urban storm runoff are used. There are various types of flow retardation measures include detention basins, retention basins, and infiltration basins. In basic planning phase, a number of planning models of detention ponds which decide storage volume by putting main variables were used to design detention ponds. The characteristics of hydrological parameters $\alpha,\;\gamma$ which are used in planning models of detention pond were analyzed. In this study, detention ponds data of Disaster Impact Assessment report at 22 sites were analyzed in order to investigate correlation between characteristic of urban drainage basin parameter and characteristics of detention pond parameter due to urbanization effects. The results showed that storage volume was influenced by peak discharge ratio $\alpha$ more than runoff coefficient ratio $\beta$ and peak discharge ratio $\alpha$ was influenced by runoff coefficient ratio $\beta$ less than regional parameter n. Storage ratio was mainly influenced by duration of design rainfall in the case of trapezoidal inflow hydrograph such as Donahue et al. method.

• Journal of Bio-Environment Control
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• v.6 no.1
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• pp.27-33
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• 1997

This experiment was carried out to investigate the effects of limited nutrient supply during 21 days before and after pollination stage on the growth, fruit quality and nutrient uptake of muskmelon in rockwool culture. Muskmelon, cv. Earl's Favorite seeds sowed on rockwool cube and transplanted on rockwool slab($90\times15\times7.5cm$) when 2 to 3 true leaf appeared on Sep. 6, 1991. Three kinds of nutrient composition recommended by Shizuoka university, combinated with the composition of Otsuka house A and composition Shizuoka III. One half of calcium nitrate(Ca(NO$_3$)$_2$.4$H_2O$) for limiting nitrogen supply during 21 days was treated and then fertigated the nutrient composition recommended by Shizuoka university up to harvest time. Trickling nozzles(Netafim Co. Israel) were used for fertigation of nutrient solution and noncirculating system was employed. Temperature was maintained $18^{\circ}C$ in night but 23 to $25^{\circ}C$ for 10 days after pollination for softening the fruit. The drainage ratio of nutrient solution was adjusted 20 to 30 percent. Fertigated and drained amount, and the pH and EC of nutrient solution were recorded. The concentrations of mineral elements including N, P, K, Ca, and Mg were analyzed and compared among treatments. In both autumn and winter cultivation, the limitation of nutrient supply by adjustment of nutrient composition(NO$_3$-N : 8meㆍ$\ell^{-1}$) caused the nutrient deficiency in muskmelon plant due to the limited nutrient supply. After pollination nutrient limitation by the lowering the nitrate retarded the over thickening of upper leaves of muskmelon but plant height and fresh weight of fruit were higher in the plot of nonlimited nutrient supply. The phenomena were attributed to the differences of the amount of nutrient uptake due to the limited time of nutrient solution, duration of nutrient supply and concentration of nutrient solution. These results suggested that increasing nutrient supply in the pollination stage was favorable for better appearance of fruit and improving fruit quality. Further trials would be required for the incre-ment of sugar degree of muskmelon grown in rockwool.

• Journal of Chest Surgery
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• v.31 no.5
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• pp.509-512
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• 1998

Although posterolateral thoracotomy(PLT) has been a standard thoracic incision in resection surgery of the lung for surgeons to achieve a good surgical field, there remains concern about severing a group of thoracic muscles remains. Muscle-sparing vertical thoracotomy (MVT) is an alternative to PLT, which gives cosmetic result and may preserve motion of the shoulder girdle as well as respiratory function of the patient in the early postoperative period. However, surgeons tend not to perfer it because of limited surgical field from the vertical wound made on the lateral thoracic wall. The purpose of this study is to compare the surgical outcomes of PLT versus MVT. We retrospectively reviewed 29 patients(15 who had PLT and 14 who had MVT, organized into those two groups) who had undergone lung resection surgery in our institute. There were no clinical differences between the two groups in terms of operation time, estimated amount of blood loss during the operation, amount of chest drainage on the first and the second postoperative day, duration of chest tube placement, incidence and amount of transfusion, and postoperative complications. We conclude that, from our limited experience, MVT can be applied to lung resection surgery as safely as PLT and that it may have a beneficial role for the patient with compromised lung function in addition to cosmetic effect.

• Journal of Chest Surgery
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• v.3 no.2
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• pp.73-90
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• 1970

Clinical perfusion data on 16 cases of cardiopulmonary bypass using Sigmamotor pump and RyggKyvsgaard Oxygenator which performed at Seoul National University Hospital during the period of Aug. 1968 to Aug. 1970 was analized. AIl cases were hemodiluted and the perfusion was carried out under the normothermic condition. The age of the patients ranged between 6 and 43 years. The b:dy weight varied between 18.3 and 54.0 kg and the body surface area between 0.78 and 1. 59$M^2$. The priming solution was consiste:I with fresh ACD blood. Hartmann solution and Mannitol. The average amount of priming was approximately 2242 ml. The average hemodilution rate was 17%. The flow rate ranged from 1.7L to 3.5L/Min/$M^2$ and averaged 2.4L/Min/$M^2$ or 78mI/Min/kg. The duration of perfusion varied from 22 to 110 min with average of 56.9 minutes. Some hemodynamic responses were observed. The arterial pressure dropped immediately after the initiation of partial perfusion and was more marked after the total perfusion foIlowed by gradual increase to the safety level. The central venous pressure reflected the reduced blood volume especially in the cases of prolonged perfusion which lasted over 60 min. In most of the cases, red blood cell count decreased and white blood ceIl count increased after the perfusion. Hemoglobin level was decreased, averaging of 12.5mg%, Hct 3.3% and platelets count of 18% postoperatively. Plasma hemoglobin increased mildly, from pre-perfusion average value of 4. 06mg% to postperfusion value of 22.5mg%. Serum potassium was 4.4mEq/L pre-operatively and was decreased to 3.7mEq/L postoperatively. Five cases showed definite hypopotassemia immediately after the operation. Sodium and chloride decreased mildly. These electrolyte changes are thought to be related with hemodilution. diuretics and reduced blood volume during and after the perfusion. Arterial blood pH value revealed minimal to moderate elevation from preperfusion average value of 7.376 to 7.461 during perfusion and then 7.365 after perfusion. The pC02 and hicarbonate showed minimal to moderately lowered values. The total CO2 was decreased. Buffer base decreased during perfusion (Av. 42.6mEq/L) and further decreased after the perfusion (Av. 40.8mEq/L). These arterial blood acid base changes suggested that the metabolic acidosis was accompanied by respiratory alkalosis during and immediately after the perfusion. Authors belived that the acidosis could more effectively be corrected with the more additional dose of bicarbonate than we used by this study. The chest tune drainage during the first 24 hours following operation was 1158 ml in average. One case (Case No. 15) showd definite bleeding tendency and it was believed that the cause might be due to the defect of heparin and protamine titration. The average urinary out put during 24 hours post-perfusion was 1291ml. One case (Case No. ]) showed definite post perfusion oliguria. As conclusion hemodilution using fresh ACD blood. Hartmann and Mannitol solution added with Bivon and high flow rate unler normothermia. was thought to amelioratc the severity of mctabolic acidosis during and after perfusion with relatively satisfactory effect on the diuresis and bleeding tendency.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.374-379
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• 1998

From March 1985 to June 1997, 451 patients of spontaneous pneumothorax treated at Kangbuk Samsung Hospital were reviewed retrospectively. Most of the patients were male (male to female ratio, 8.2:1). The mean age of the primary spontaneous pneumothorax (PSP) was 26.8 years, and that of secondary spontaneous pneumothorax(SSP) was 53.1 years. 330 out of 451 patients(73%) were PSP. The causes of the SSP were mostly pulmonary tuberculosis and COPD: 87 patients(72%), and 24 patients(19.2%), respectively. All the patient were treated by one of the following modalities: 1)rest and oxygen therapy in 42 patients, 2) closed thoracostomy in 208 patients, 3) thoracotomy in 156 patients, 4) VATS bullectomy in 45 patients. The mean duration of postoperative chest tube drainage was as following: thoracotomy 8.3 days, VATS bullectomy 4.7 days. For recent 3 consecutive years, VATS bullectomy has become the more frequently applied operative procedure than thoracotomy in the treatment of surgically indicated PSP, from 33% in 1994 to 78% in 1996. With the minimally invasive thoracoscopic surgery being more prevalent, VATS bullectomy will be able to be the 1st choice of treatment not only for the recurrent pneumothoracies but also for the some selected cases of the 1st episode pneumothoracies. To verify this approach as clinically acceptable one in terms of cost-effectiveness, recurrence rate, etc, a large scale of multi-institutional clinical study will be needed in a sooner time.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.1
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• pp.28-38
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• 2004

The purpose of this study is to analyze the urban hydrologic state by the use of GIS, resolution and interpolation. The determination coefficient($R^2$) and Regression Formula were derived from the contour of digital map for the accuracy, and DEM data was made by using TIN interpolation by the size of the grid. By using the observed DEM data, topographical factors were extracted from the small basin, size, the width of a basin and the slope, and were applied in the urban runoff model. Through the model, we tried to find out the most suitable runoff model in a small basin of Yosu-Munsu area. As a result of applying models to the drainage considered, the runoff hydrograph estimated by SWMM model was closer to the observed one than that estimated by ILLUDAS model. The difference between the runoff hydrograph by SWMM and the observed one is maximum error of 19%, minimum error of 5% and average error of 13%. The influence of duration in contrast to pick time is insignificant in a urban small basin. As a conclusion of this study, SWMM model was more suitable and applicable for the urban runoff model than ILLUDAS model due to its accuracy and various abilities.

• Geomechanics and Engineering
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• v.24 no.2
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• pp.115-127
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• 2021

This paper investigates the effects of soaking on a lime stabilized high plasticity clay and evaluates the implications for pavement design. In this context, the soil was stabilized by 4%, 6% and 9% hydrated lime. The soil was pulverized in two different gradations so that representative field gradations could be simulated. Both soil pulverization levels passed the relevant field gradation criteria. Curing durations were chosen as 7 days, 28 days and 56 days. Two groups of samples were prepared and were tested in unconfined compression test apparatus to measure the strength and secant modulus at failure values. One of the groups was tested immediately after curing. The other group of samples were first cured and then subjected to soaking for ten days before testing. Visual observations were made on the samples during the soaking period. The results showed the superiority of fine soil pulverization over coarse soil pulverization for unsoaked conditions in terms of strength and modulus values. Soaking of the samples affected the unconfined compressive strength and modulus values based on lime content, curing duration and soil pulverization level. In soaked samples, fine soil pulverization resulted in higher strength and modulus values compared to coarse soil pulverization. However, even with fine soil pulverization, effects of soaking on modulus values were more significant. A new term named as "Soaking Influence Factor (SIF)" was defined to compare the reduction in strength and modulus due to soaking. The data was compared with the relevant design guidelines and an attempt was made to include Soaking Influence Factors for strength and modulus (SIFS and SIFM) into pavement design processes. Two equations which correlated secant modulus at failure to unconfined compressive strength were proposed based on the samples subjected to soaking. The results of this study showed that in order to decrease the diverse effects of soaking for lime stabilized soils, soil pulverization level should be kept as fine as possible in the field. Importance of proper drainage precautions in the pavements is highlighted for better performance of the pavements.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.1-10
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• 2023

This study aimed to confirm the importance ratio of climate and management variables on production of orchardgrass in Korea (1982-2014). For the climate, the mean temperature in January (MTJ, ℃), lowest temperature in January (LTJ, ℃), growing days 0 to 5 (GD 1, day), growing days 5 to 25 (GD 2, day), Summer depression days (SSD, day), rainfall days (RD, day), accumulated rainfall (AR, mm), and sunshine duration (SD, hr) were considered. For the management, the establishment period (EP, 0-6 years) and number of cutting (NC, 2nd-5th) were measured. The importance ratio on production of orchardgrass was estimated using the neural network model with the perceptron method. It was performed by SPSS 26.0 (IBM Corp., Chicago). As a result, EP was the most important variable (100%), followed by RD (82.0%), AR (79.1%), NC (69.2%), LTJ (66.2%), GD 2 (63.3%), GD 1 (61.6%), SD (58.1%), SSD (50.8%) and MTJ (41.8%). It implies that EP, RD, AR, and NC were more important than others. Since the annual rainfall in Korea is exceed the required amount for the growth and development of orchardgrass, the damage caused by heavy rainfall exceeding the appropriate level could be reduced through drainage management. It means that, when cultivating orchardgrass, factors that can be controlled were relatively important. Although it is difficult to interpret the specific effect of climates on production due to neural networking modeling, in the future, this study is expected to be useful in production prediction and damage estimation by climate change by selecting major factors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.56-63
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• 2018

The management of Combined Sewer Overflows(CSOs) and Separated Sewer Overflows(SSOs) discharge directly to the effluent system in an untreated state, which occurs when the facility capacity is exceeded due to heavy rain, has become an important issue in recent years as the heavy rain becomes a regular phenomenon. Despite the continuous development of filtration technology, targeting densely populated urban areas, CSOs are rarely applied. Therefore, this study was carried out to optimize the process to apply CSOs in a pilot-scale horizontal flow filtration system with a rope-type synthetic fiber. The research was carried out in two steps: a preliminary study using artificial samples and a field study using sewage. In the preliminary study using an artificial sample, head loss of the filter media itself was analyzed to be approximately 1.1cm, and the head loss was increased by approximately 0.1cm as the linear velocity was increased by 10m/hr. In addition, the SS removal efficiency was stable at 81.4%, the filtration duration was maintained for more than 6 hours, and the average recovery rate of 98% was obtained by air backwashing only. In the on-site evaluation using sewage, the filtration duration was approximately 2 hours and the average removal efficiency of 83.9% was obtained when belt screen (over 450 mesh) was applied as a pre-treatment process to prevent the premature clogging of filter media. To apply the filtration process to CSOs and SSOs, it was concluded that the combination with the pre-treatment process was important to reinforce the hydraulic dimension for the stable maintain of operation period, rather than efficiency. Compared to the dry season, the quality of incoming sewage was lower in the rainy season, which was attributed to the characteristics of the drainage area with higher sanitary sewerage. In addition, the difference in removal efficiency according to the influent quality of the wet season and dry season was small.