• Journal of Chest Surgery
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• v.25 no.11
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• pp.1318-1326
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• 1992

Backgroud. To determine the influence of age at operation upon surgical outcome in patients with isolated secundum atrial septal defect, retrospective clinical analysis was done. Material and method. From June, 1976 to December, 1991, 146 patients, 63 male and 83 female patients ranging in age from 13 months to 56 years, were operated on for isolated secundum atrial septal defect. The patients were divided into 3 groups according to their age at operation: Group I [<20 years old], 91 patients[62.3%]; Group II [21 to 40 years old], 44 patients[30.1%]; GroupIII[>41 years old], 11 patients[7.6%]. Significant differences in clinical features, hemodynamic function, early and late results between age groups were speculated. Results. One hundred thirty-one patients[89.6%] were symptomatic at the time of operation, the most common symptoms being dyspnea on exertion, recurrent respiratory infection, palpitation and chest pain. Patients in NYHA class III or IV were 3.3% in group I, 25% in groupIII, and 54.5% in group Ill. Hemodynamic data was available for 138 patients [94.5%]. Significant pulmonary hypertension [MPA systolic pressure $^3$ 40mmHg] was noted in 22 patients [15.9%]. Patients with pulmonary vascular disease [Rp/Rs>1.25] were 2% in group I, 7.3% in group Il, and 9.1% in groupIII. But there were no significant differences between the age groups in the size of the shunt or the ratio of pulmonary to systemic flow. Atrial septal defects were closed with direct suture in 144 patients and patch repair was performed in 2 patients with high defect. Atrial arrhythmia [8.2%] was the most common postoperative complication. The mean [LSD] duration of follow-up in all patients was 16$\pm$22 months [range, 1~96 months]. Functional result was excellent regardless of the age groups. During follow-up period, late cardiovascular events were arrhythmia [7 cases], reoperation for recurrent ASD [2 cases], and premature late death due to bacterial endocarditis [1 case]. Incidence of preoperative and late atrial fibrillation was significantly higher in older age group. Conclusion. Age at operation is one of the most important predictor of early and late surgical outcome with its impact on the following factors : 1] hemodynamic alterations and ventricular dysfunction due to longstanding volume and pressure overload, 2] pulmonary vascular disease, and 3] atrial arrhythmia including atrial fibrillation as a result of atrial dilatation. Therefore, among patients with surgically repaired atrial septal defects, those operated on over the age of 20 require careful supervision on the long-term basis.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1048-1052
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• 2007

그동안의 하천 유량자료는 주로 홍수방어를 목적으로 구축되어진 관계로 대부분 홍수기에만 의미있는 자료를 갖추고 있으며, 환경관리에 필요한 저갈수기 유량자료는 그 신뢰도가 매우 떨어지고 있다. 다행히 지난 2004년 하반기부터 4대강 물환경 연구소에서 직접 오염총량관리 단위유역 말단부에서 8일 간격으로 유량과 수질을 동시에 측정하기 시작하였고, 사업의 결과 건기 우기의 구별 없이 연중 일정한 간격으로 하천유황 및 수질의 변동여부를 확인하는 것이 가능하게 되었으나, 각 단위유역별 유황곡선을 작성할 목적으로 8일 간격 유량자료를 사용할 수 없다는 단점이 있다. 즉, 현재 관측 중인 8일 간격 유량자료만으로는 동시 관측이 진행 중인 수질항목과 유량 사이의 상관관계 정도를 파악한다거나, 어떤 방법으로든 수문모형을 구축한 후 이를 부분적으로 검정할 때 참고자료로 사용하는 정도로 그 용도가 한정될 수밖에 없는 실정이다. 이에 본 연구에서는 낙동강 오염총량관리 41개 단위유역 전체를 대상으로 관측된 8일 간격 유량자료를 이용하여 이를 1일 간격 유량자료로 확장을 시도하였다. 이를 위하여 기존의 TANK 모형에 하도추적기능을 추가한 보다 진보된 TANK 모형을 구성하였다. 낙동강 단위유역별 취수량과 방류량을 바탕으로 한 물수지 자료 또한 구비하여 모형에 고려되도록 하였다. 모형의 매개변수 추정을 위하여 국립환경과학원 낙동강물환경연구소에서 8일 간격으로 관측한 유량자료가 이용되었다. 분석결과 모의된 일유량이 실제 유량을 비교적 잘 재현하는 것으로 나타남에 따라 8일간격 유량관측자료의 일유량으로의 확장 가능성을 확인할 수 있었다. 구축된 모형은 적용에 앞서 10년 평균 저수량을 기준으로 1차 오염총량관리 기준유량과의 비교를 시도하였으며, 상류 댐 방류의 영향 및 물수지의 영향을 배제한 상태의 자연유량을 산정하여 이를 현재 유황과의 비교를 수행하였다. 현재유량과의 비교 결과 다목적 댐의 방류효과로 인한 유량 증가효과 및 대규모의 취수로 인한 유량 감소효과가 뚜렷하게 나타남을 알 수 있었다. 산정된 자연유량을 통하여 비유량을 산정한 결과 $5,000km^2$이하인 유역 면적의 경우 비유량 $0.0048m^3/s/km$를, $5,000km^2$이상인 경우에는 비유량 $0.0043m^3/s/km$를 적용하는 것이 바람직할 것으로 분석되었다. 여기에 유역의 물이용 및 상류의 댐 방류 효과가 고려되면 실제 유역의 저수량을 개략적으로 산정할 수 있을 것으로 기대된다.

• Environmental Analysis Health and Toxicology
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• v.11 no.1_2
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• pp.19-29
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• 1996

Human exposure to volatile compounds in tap water can occur from inhalation and dermal absorption as well as direct ingestion. The relative contribution to total human exposure from these pathways has been considered to be important especially for VOC's (volatile organic compounds). In an attempt to reduce the uncertainty of the risk assessment, it has been suggested that the exposure assessment process could be significantly improved by adopting Monte-Carlo simulation. However, there is no actual data in Korea for each exposure parameter to determine the level of exposure, and the distributional pattern. Therefore, we surveyed water use patterns and behavior related to multi-route exposure to VOC's in household tap water in Korea, and compared these values to the those in western countries. In the first survey, we calculated daily water intake using data from a sample of 1322 persons of several cities in Korea. In the second survey, we obtained questionnaire data on exposure time for showering, bathing and household activities, and tap water intake from 851households in Korea. In the last survey, we measured the exposure parameters (exposure time, water use rate etc.) related to showers, baths, toilets, dish washing, washing and cooking, and tap water intake was surveyed. Also, the subjects were measured their body weight, height and tidal volume, etc. A diary, a flow meter and a measuring cup were used to measure these values as precisely as possible. Average daily water intake was ranged 0.79-1.71 L/day for adults in three surveys. Tap water intake measured by log-sheet during one week in third survey was 1.26 (average), 1.98 L/day (90 percentlie), respectively. These results were comparable with results from EPA (1.4, 2L/day). The average amount of water used by housewives in the third survey was 515.0 $\pm$ 564.6L/day. In usual activity, the amount of water used in the bathroom, the laundry and the kitchen was 140.0 $\pm$ 538.9, 148.0 $\pm$ 174.5, 229.3 $\pm$ 205.4 L/day, respectively. Exposure parameters such as water intake rate, exposure duration, body weight, inhalation rates in surveyed data of Korean people differed from those published from western countries. This could be attributed to variations in lifestyle, dietary habits and physiological characteristics.

• Journal of Korea Water Resources Association
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• v.51 no.1
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• pp.19-33
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• 2018

This study proposed a rainfall-runoff model for the purpose of real-time flood warning in urban basins. The proposed model was based on the shot noise process, which is expressed as a sum of shot noises determined independently with the peak value, decay parameter and time delay of each sub-basin. The proposed model was different from other rainfall-runoff models from the point that the runoff from each sub-basin reaches the basin outlet independently. The model parameters can be easily determined by the empirical formulas for the concentration time and storage coefficient of a basin and those of the pipe flow. The proposed model was applied to the total of three rainfall events observed at the Jungdong, Guro 1 and Daerim 2 pumping stations to evaluate its applicability. Summarizing the results is as follows. (1) The unit response function of the proposed model, different from other rainfall-runoff models, has the same shape regardless of the rainfall duration. (2) The proposed model shows a convergent shape as the calculation time interval becomes smaller. As the proposed model was proposed to be applied to urban basins, one-minute of calculation time interval would be most appropriate. (3) Application of the one-minute unit response function to the observed rainfall events showed that the simulated runoff hydrographs were very similar to those observed. This result indicates that the proposed model has a good application potential for the rainfall-runoff analysis in urban basins.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.3
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• pp.286-293
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• 2021

Objectives: Inorganic dust is known to be a risk factor for chronic obstructive pulmonary disease (COPD) regardless of smoking and pneumoconiosis. Adaptive and innate immunity, including lymphocyte infiltrate, are involved in the pathogenesis of COPD. The purpose of this study was to analyze the lymphocyte subsets in the blood of workers exposed to inorganic dust and confirm the influencing factors. Methods: The general characteristics of the subjects (n=107) were analyzed through a personal questionnaire. Diagnosis of COPD was established according to pulmonary function tests with FEV₁/FVC post bronchodilator lower than 70%, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. For lymphocyte analysis, blood was stained with a fluorescent CD marker and analyzed by flow cytometry. Results: The increase in CD4⁺ T lymphocytes was associated with a decrease in age (𝛽=-0.273, p=0.008) and an increase in the cumulative smoking amount (𝛽=0.205, p=0.034). The increase in NK cells was associated with an increase in age (𝛽=0.325, p=0.001) and a decrease in cumulative smoking (𝛽=-0.220, p=0.019). The period of exposure to dust, %FVC predicted and %FEV₁/FVC, and the relative population of peripheral blood lymphocytes did not show a statistically significant relationship. Conclusions: CD4⁺ T lymphocytes and CD56⁺CD16⁺ NK cells in peripheral blood were more related to age and cumulative smoking than the duration of dust exposure. Age and smoking are major risk factors for the development of COPD, so it can be predicted that peripheral blood CD4⁺ T lymphocytes and CD56⁺CD16⁺ NK cells are related to the development of COPD in workers exposed to inorganic dust.

• Korean Association of Arts Management
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• no.59
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• pp.73-99
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• 2021

Free admission policies have been gradually extended for the public to use cultural facilities free of charge, which lowered the barriers to use those facilities and has a great effect on increasing visitor demands. However, the annual number of visitors which is open to the public isn't quite accurate and varies from institution to institution, which means just a head count. Especially people counter overestimates the number of visitors because it counts visitors in duplicate. Therefore, the purpose of this study is to prepare effective way of grasping the number of visitors using cultural infrastructure. First, comparable number of visitors should be measured by defining the notion of visitor clearly, which has been measured vaguely. Secondly, the problem of duplicate count, which is considered the most problematic, should be solved. Thirdly, the various analysis of visitor behavior should be conducted to provide a high-quality service. To work out the problems above, new measurement will be presented here. This study suggests a state-of-the-art wireless signal-based measurement that could eliminate the duplicate data by collecting MAC address -smart device's distinct signal value. And it also could analyze diverse visitor behaviors by understanding a flow of visitor traffic, duration of stay and revisitation. I would like to examine the possibility and effectiveness of this new measurement by testing it.

• Korean Association of Arts Management
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• no.53
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• pp.207-247
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• 2020

is a project for the senior generation with humanistic knowledge to become a mentor and communicate with them to present the wisdom and direction of life to the new generations of mentees based on various life experiences. has been expanding since 2015, starting with the pilot operation in 2014. In general, projects such as these are assessed to establish effectiveness indicators to verify effectiveness and to establish project management and development strategies. However, most of the evaluations have been conducted quantitatively and qualitatively based on the short-term duration of the project. Therefore, in the case of continuous projects such as , especially in the field of culture and arts where long-term effectiveness verification is required, the short-term evaluation is difficult to predict and judge the actual meaningful effects. In this regard, tried to examine the qualitative change of key participants in this project through the 2017 and 2018 image tracking survey. For this purpose, we adopted qualitative research methodology through interview video shooting, field shooting, and value coding as a research method suitable for the research subject. To analyze the results, first, the interview images were transcribed, keywords were extracted, value encoding works were matched with human psychological values, and the theoretical method was used to identify changes and to derive the meaning. In fact, despite the fact that the study conducted in this study was a follow-up survey, it remained a limitation that it analyzed the changed pattern in a rather short time of 2 years. However, this study systemized the specific methodology that researchers should conduct for follow-up and provided the flow of research at the present time when there is hardly a model for follow-up in the field of culture and arts education business in Korea as well as abroad. Significance can be derived from this point. In addition, it can be said that it has great significance in preparing the detailed system and case of comparative analysis methodology through value coding.

• Korean Circulation Journal
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• v.54 no.6
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• pp.325-335
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• 2024

Background and Objectives: The number of sensitized heart failure patients on waiting lists for heart transplantation (HTx) is increasing. Using the Korean Organ Transplantation Registry (KOTRY), a nationwide multicenter database, we investigated the prevalence and clinical impact of calculated panel-reactive antibody (cPRA) in patients undergoing HTx. Methods: We retrospectively reviewed 813 patients who underwent HTx between 2014 and 2021. Patients were grouped according to peak PRA level as group A: patients with cPRA ≤10% (n= 492); group B: patients with cPRA >10%, <50% (n=160); group C patients with cPRA ≥50% (n=161). Post-HTx outcomes were freedom from antibody-mediated rejection (AMR), acute cellular rejection, coronary allograft vasculopathy, and all-cause mortality. Results: The median follow-up duration was 44 (19-72) months. Female sex, re-transplantation, and pre-HTx renal replacement therapy were independently associated with an increased risk of sensitization (cPRA ≥50%). Group C patients were more likely to have longer hospital stays and to use anti-thymocyte globulin as an induction agent compared to groups A and B. Significantly more patients in group C had positive flow cytometric crossmatch and had a higher incidence of preformed donor-specific antibody (DSA) compared to groups A and B. During follow-up, group C had a significantly higher rate of AMR, but the overall survival rate was comparable to that of groups A and B. In a subgroup analysis of group C, post-transplant survival was comparable despite higher preformed DSA in a desensitized group compared to the non-desensitized group. Conclusions: Patients with cPRA ≥50% had significantly higher incidence of preformed DSA and lower freedom from AMR, but post-HTx survival rates were similar to those with cPRA <50%. Our findings suggest that sensitized patients can attain comparable post-transplant survival to non-sensitized patients when treated with optimal desensitization treatment and therapeutic intervention.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.464-472
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• 2009

Background: We analyzed the clinical results and the factors for survival of patients who underwent extracorporeal life support system after adult cardiovascular surgery. Material and Method: We retrospectively reviewed the medical record of 44 patients (1.6% of the total adult cardiovascular surgical cases) who underwent the use of a ventricular assisted device or extracorporeal membrane oxygenation from January 2002 to August 2008. There were 32 (72.7%) males and their mean age was 61.7$\pm$14.9(range: 20$\sim$73) years old. The mean duration of extracorporeal life support system was 5.3$\pm$3.0 (range: 1$\sim$12) days. Result: Of these 44 patients, 24 (54.5%) patients were successfully weaned from the extracorporeal device. Eighteen (40.9%) survivors were able to be discharged from the hospital. Complications were noted in 38 patients (86.4%). An emergency operation, no usage of a concomitant intraaortic balloon pump and major complications during use of the extra corporeal life support system such as bleeding, flow instability and renal failure were identified as significant risk factors for poor survival on univariated analysis. Owing to educational support and a continuous renal replacement therapy system, the clinical outcomes of these patients have improved since 2006. On multivariated analysis, renal failure and bleeding during extracorporeal life support were significant risk factors for poor survival. Conclusion: Although using. extracorporeal life support systems after adult cardiovascular surgery revealed acceptable clinical results, determining the optimal treatment strategy and further well designed larger studies are needed to improve the survival rate of patients who undergo extracorporeal life support after adult cardiovascular surgery.

• Journal of Korea Water Resources Association
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• v.44 no.10
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• pp.797-807
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• 2011

Phenomenon of vegetation recruitment on the sand bar is drastically rising in the streams and rivers in Korea. In the 1960s prior to industrialization and urbanization, most of the streams were consisted of sands and gravels, what we call, 'White River'. Owing to dam construction, stream maintenance, etc. carried out since the '70s, the characteristic of flow duration and sediment transport have been disturbed resulting in the abundance of vegetation in the waterfront, that is, 'Green River' is under progress. This study purposed to identify the correlation among water level, water temperature, rainfall, soil moisture and soil texture out of the factors which give an effect on the vegetation recruitment on the sand bar of unregulated stream. To this purpose, this study selected the downstream of Naeseong Stream, one of sand rivers in Korea, as the river section for test and conducted the monitoring and analysis for 289 days. In addition, this study analyzed the aerial photos taken from 1970 to 2009 in order to identify the aged change in vegetation from the past to the present. The range of the tested river section was 361 m in transverse length and about 2 km in longitudinal length. According to the survey analysis, the tested river section in Naeseong Stream was a gaining river showing the higher underground-water level by 20~30 m compared to Stream water level. The difference in the underground water temperature was less than $5^{\circ}C$ by day and season and the Stream temperature did not fall to $10^{\circ}C$ and less from May when the vegetation germination begins in earnest. The impact factor on soil moisture was the underground water level in the lower layer and the rainfall in the upper layer and it was found that all the upper and lower layer were influenced by soil particle size. The soil from surface to 1 m-underground out of 6 soil moisture-measured points was sand with the $D_{50}$ size of 0.07~1.37 mm and it's assumed that the capillary height possible in the particle size would reach around 14~43 cm. On the other hand, according to the result of space analysis on the tested river section of unregulated stream for 40 years, it was found that the artificial disturbance and drought promoted the vegetation recruitment and the flooding resulted in the frequency extinction of vegetation communities. Even though the small and large scales of recruitment and extinction in vegetation have been repeated since 1970, the present vegetation area increased clearly compared to the past. It's found that the vegetation area is gradually increasing over time.