• Journal of Chest Surgery
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• v.38 no.3 s.248
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• pp.204-213
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• 2005

In spite of the improvement in the quality of artificial heart valves and surgical techniques, the incidence of the complications following valve replacement is still high. We reviewed the clinical results of the valve replacements peformed in Korean University Anam Hospital during the last 26 years. Material and Method: The data of 571 patients who received valve replacement between December 1976 and December 2003 were reviewed. Result: There were 304 cases of MVR which was the most common procedure performed. There were 122 cases of AVR, and 111 cases of AVR with MVR. Among the 47 patients who received redo operation 38 cases were redo cases including 31 cases of MVR. $32.5\%$ of the patients who had tissue valve replacement had second valve replacement with 10.2 $\pm$ 3.9 years interval. $24.3\%$ (139/571) of the patients developed valve related complications and cerebral infarction was the highest in frequency. Atrial fibrillation was related with increased complication rates and the mechanical valve replaced group had higher hemorrhagic complication rate than tissue valve replaced group. The operative mortality was $3.68\%$ and the most common cause of the failure was low output syndrome. The operative mortality was higher in the patient group who had valve replacement before the year 1990. The patient group who had mechanical valve replacement had higher operative mortality rate th;3n the tissue valve group. The 5-year survival rate was $92.2\%$ and 10 year survival rate was $85.7\%$. Conclusion: The operative mortality of valve replacement has been improved. The mechnical valve replaced patients had higher hemorrhagic complication rate than the tissue valve replaced patients and more tissue valve replaced patients received redo valve replacement.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.2
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• pp.20-33
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• 2020

This study aims to examine the trends in the preservation of urban public parks with a focus on the international movement to acknowledge and preserve the heritage value of urban parks. First, the background in which the concept of "historic urban park" first appeared internationally, as well as the current situation were investigated. Then, the cases of the United Kingdom (UK), the United States (US), and Japan, all of which are already preserving and managing urban public parks, were analyzed. In the ICOMOS-IFLA Document on Historic Urban Public Parks, the International Council on Monuments and Sites (ICOMOS), which is a group of specialists dedicated to the conservation and management of cultural heritage, mentions that it is necessary to maintain the social, intangible, aesthetic, ecological, and civic values of historic urban public parks. In addition, according to ICOMOS, it is necessary to preserve elements of parks, such as space composition, topography, light, and environment. The UK, the USA, and Japan have their own unique characteristics for the background of preserving urban parks, the preservation system, the selection of parks to be preserved, and the elements to be preserved within the park. The UK has categorized parks into certain types from each period and has tried to preserve the common elements in each type. The US has selected the parks to preserve by determining the meaning of the parks itself considering multiple aspects, embracing not only the physical form of the parks, but also the culture, monumentality, and social values. Recently, Japan began the preservation of historic urban parks as a matter of policy and started to implement a preservation policy by investigating modern parks that are believed to be worth preserving. Specialists in cultural heritage preservation have argued that the method of preservation of historic urban parks must differ from that of other parks or gardens. Nonetheless, observing cases in these three countries showed that, regardless of their administrative and legal systems regarding cultural heritage and urban public parks, their policies were still limited to preserving only the physical elements of parks. The direction and methodology for the preservation of historic urban parks must be developed further and elaborated upon in terms of the evolving concept and definition of heritage. Urban parks are where various historic values are accumulated, connoting historical meanings dealing with the memories of the parks and the urban dwellers. This study found that, worldwide, park management has been carried out in a way that the historic values of parks are respected and preserved. This global trend in preserving the historic values of urban public parks has significant implications for the management of urban public parks in Korea that are being formed and renewed repeatedly.

• Clinical and Experimental Pediatrics
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• v.51 no.6
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• pp.604-609
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• 2008

Purpose : Obesity in children and adolescence is highly correlated with adult obesity, which can provoke hypertension. Therefore, it is important to evaluate the blood pressure of obese children regularly. In this study, the results of ambulatory blood pressure monitoring (ABPM) in obese children and adolescents were evaluated. Methods : ABPM was conducted for selected patients who visited Handong University Sunlin Hospital from Feb. 1, 2006 to Dec. 1, 2007. The patients were classified into 3 groups: group 1 was normal, group 2 had normal casual blood pressure and a body mass index over the 95th percentile, and group 3 had high casual blood pressure over 120/80 mm Hg and a body mass index over the 95th percentile. Systolic and diastolic 24-hour blood pressure was measured, including both day and night. Results : There were 49 patients in the study. The results showed a significant difference for average systolic blood pressure between the three groups ($105.1{\pm}4.7$, $111.0{\pm}7.1$, $117.8{\pm}6.6mmHg$, P<0.001), but for average diastolic blood pressure only between groups 1 and 3 ($69.1{\pm}5.3$, $77.9{\pm}6.3mmHg$, P=0.001). In the daytime, only groups 1 and 3 showed a statistically significant difference for systolic and diastolic blood pressure. During the night the systolic pressure of group 3 was significantly higher than the other groups, but the diastolic pressure of group 3 was only higher than that group 1. No statistical difference was found in night dips among the groups. Conclusion : Ambulatory blood pressure monitoring in children and adolescents showed statistically higher blood pressure in obese patients with high casual blood pressure.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.267-282
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• 2018

Despite the continuous development of phenology detection studies using satellite imagery, verification through comparison with the field observed data is insufficient. Especially, in the case of Korean forests patching in various forms, it is difficult to estimate the start of season (SOS) by using only satellite images due to resolution difference. To improve the accuracy of vegetation phenology estimation, this study reconstructed the large scaled forest type map (1:5,000) with MODIS pixel resolution and produced time series vegetation phenology curves from Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) derived from MODIS images. Based on the field observed data, extraction methods for the vegetation indices and SOS for Korean forests were compared and evaluated. We also analyzed the correlation between the composition ratio of forest types in each pixel and phenology extraction from the vegetation indices. When we compared NDVI and EVI with the field observed SOS data from the Korea National Arboretum, EVI was more accurate for Korean forests, and the first derivative was most suitable for extracting SOS in the phenology curve from the vegetation index. When the eight pixels neighboring the pixels of 7 broadleaved trees with field SOS data (center pixel) were compared to field SOS, the forest types of the best pixels with the highest correlation with the field data were deciduous forest by 67.9%, coniferous forest by 14.3%, and mixed forest by 7.7%, and the mean coefficient of determination ($R^2$) was 0.64. The average national SOS extracted from MODIS EVI were DOY 112.9 in 2014 at the earliest and DOY 129.1 in 2010 at the latest, which is about 0.16 days faster since 2003. In future research, it is necessary to expand the analysis of deciduous and mixed forests' SOS into the extraction of coniferous forest's SOS in order to understand the various climate and geomorphic factors. As such, comprehensive study should be carried out considering the diversity of forest ecosystems in Korea.

• Journal of Bio-Environment Control
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• v.2 no.2
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• pp.89-98
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• 1993

The purpose of this study was to investigate crop growth responses under various rain shelters which were devised to improve the indoor environment in summer season. For developing the proper type of rain shelter, the improved rain shelters with the roof of saw - tooth type(saw-tooth type) and 3 span-arch type(improved arch type) were compared with the conventional one with the roof of single arch type(conventional arch type) and no rain shelter (open field ). The results were summarized as follows ; 1. The air temperature in the improved arch type was 4$^{\circ}C$ and 1$^{\circ}C$ lower than those in the conventional arch type and the saw - tooth type, respectively. 2. The air temperature drop by the evaporative cooling + improved drainage was 1.3$^{\circ}C$ which was 0.9$^{\circ}C$lower than that by the improved drainage only. 3. The effect of labour saving in the saw-tooth type was superior to any other type because its frames were used as props and the labour for ventilation was not needed. 4. The highest marketable yield of tomato was 4,897kg/10a in the improved arch type and the total leaf areas which related to photosynthesis was the largest in the saw - tooth type. 5. The improved arch type was proved to be proper to raise yield potential. The effect of the underground environment treatment on the quality and quantity of vegetable showed to be outstanding in the saw- tooth type with the evaporative cooling + improved drainage, and in the improved and conventional arch type with the trickle improved drainage. 6. In conclusion, the saw - tooth type and the improved arch type were proved to be labour saving rain shelters and the indoor environments in both types were better than that in the conventional arch type.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.1
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• pp.33-46
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• 2017

In Korea, small and medium sized domestic enterprises (SMEs) play an pivotal role in the national economy, accounting for 99.8% of all enterprises, 87.9% of total employment, and 48.3% of production. and SMEs were driving a real force of the development of national economy in many respects such as innovation, job creation, industrial diversity, balanced regional development. Despite their crucial role in the national development, most of SMEs suffer from a lack of R&D capabilities and equipments as well as funding capacity. Government-Supported Research Institute (GRI) can provide SMEs with valuable supplementary technological knowledges and help them build technological capacities. so, In order to effectively support SMEs, government and GRI must be a priority to know about the factors influencing the performance related to technology transfer and technological collaborations. The paper analyzes the effects of Korean IT SMEs Venture external collaborations and technology transfer on their performances, according to their collaboration activities and technology transfer experiences. The results show that there was a significant difference between '3~5times' of technology transfer experience and 'zero technology transfer experience' in the case of technology transfer experience. In case of technological collaboration type, there was a significant difference between 'R&D manpower' and 'enhancement of technological capabilities including core technologies'. The results show that the effectiveness of technology transfer of Korean IT SMEs Venture depends on experiences, types of collaboration activities. so the results of this research will be useful for Government-Supported research institute (GRI)' policy makers when establishing technology commercialization support policies and strategic planning of small and medium sized domestic enterprises.

• 대한공업교육학회지
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• v.38 no.1
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• pp.1-27
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• 2013

The purpose of this study was to find out the areas and their constitute elements of new apprenticeship through the expert of vocational education to improve the growth potential in the field of industry. Through the three times Delphi research process final composing areas and elements(total 6 areas and 41 sub-elements) of new apprenticeship were extracted. Followings are specific study results of 41 sub-elements for the 6 areas. In area A(Technology Skill aspect) total nine sub-elements were deducted as follows. Technology skill's field appling ability, new technology skill's acquisition, quality assurance ability, research development ability, material management using ability, problem solving ability, core technology skill understanding ability, idea's imagery expressing ability, creative design ability. In area B(Institutional aspect) total five sub-elements were deducted as follows. Flexible human material support, precise division of works, objective result assessment, institutionalization of responsibilities and liabilities between teacher and student, institutionalization of duty invention reward. In area C(Affective aspect) total eight sub-elements were deducted as follows. Manners and cooperation between teacher & student and peer, values for job, basic attitude for technology, job ethic sense, respect of other organization, active action to organization change, attitude of technology successor, service mind. In area D(Self-improvement aspect) total nine sub-elements were deducted as follows. Self evaluation and reflection, cultivate of organization understanding, career planning and developing ability, sound philosophy of life, communication ability, decision making ability, prepare of individual competence enhance system, self-control ability improvement, reaction of unexpected situation. In area E(Knowledge aspect) total four sub-elements were deducted as follows. Basic knowledge of relevant area, knowledge of new technology & preceding technology, fusion and relocation of knowledge, practical knowledge. In area F(Environmental aspect) total six sub-elements were deducted as follows. Awareness of business environment, understanding of education and practice environment, understanding of apprenticeship's business demand, connectivity of region community, adapt ability of labor market's change, awareness of society environment change.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.69-69
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• 2011

태양열 발전 플랜트에 사용되는 중고온 범위의 축열조에 고체-액체간 상변화를 수행하는 용융염을 축열물질로 사용하면 액체상 또는 고체상만으로 된 열저장 매체에 비해 축열조의 규모를 축소함과 동시에 축열온도의 균일성 향상에 기여할 수 있다. 중온인 $250{\sim}400^{\circ}C$ 범위에서 이용 가능한 용융염으로는 질산칼륨($KNO_3$), 질산리튬($LiNO_3$)등이 있다. 그러나 이러한 용융염의 가장 큰 단점은 열전도율이 매우 낮다는 것이며, 이로 인해 요구되는 열전달률을 성취하기 위해서는 많은 열접촉면적이 필요하다는 것이다. 이러한 단점을 극복하는 방법을 도입하지 않고서는 축열시스템의 소규화를 성취하는데 큰 효과를 가져올 수 없다. 한편 열수송 성능이 탁월한 히트파이프를 사용하면 열원 및 열침과 축열물질 사이의 열전달 효율을 증가시켜 시스템의 성능 향상과 동시에 소규모화에 기여할 수 있다. 중온 범위 히트파이프의 작동유체로서 다우섬-A(Dowtherm-A)는 $150^{\circ}C$이상 $400^{\circ}C$까지의 범위에서 소수에 불과한 선택적 대안 중 하나이다. 따라서 본 연구에서는 용융염을 사용하는 중온 태양열축열조에 적용 가능한 다우섬-A 히트파이프의 성능을 파악하여 기술적 자료를 제시하고자 하였다. 열원으로는 고온 고압의 과열증기, 그리고 열침으로는 중온의 포화증기를 고려하였다. 용융염 축열조를 수직으로 관통하는 히트파이프는 하단부에서 열원 증기와 열교환 가능하며, 중앙부에서 축열물질과 열교환하고, 상단부에서는 중온 증기와 접촉할 수 있도록 배치하였다. 축열모드에서는 히트파이프의 하단부가 증발부로 작동하고, 중앙부가 응축부로 작동하여 용융염으로 열을 방출하면 용융염의 온도가 상승하고 용융점에 도달하면 액상으로의 상변화가 진행되면서 축열이 활성화된다. 축열모드에서 히트파이프의 상단부는 단열부로 작동한다. 방열과정에서는 히트파이프의 하단부가 단열된 상태이고, 중앙부는 용융염으로부터 열을 받아 증발부로 작동하며, 상단부는 중온 증기로 열을 방출하므로 응축부로 작동한다. 즉, 축열시스템의 작동모드에 따라 하나의 히트파이프에서 증발부, 응축부, 단열부의 위치가 변하게 된다. 특히, 히트파이프의 중앙 부분이 응축부에서 증발부로 전환될 때에도 작동이 보장되려면 내부 작동유체의 연속적인 재순환이 가능해야 하므로, 일반 히트파이프에서와는 달리 초기 작동액체의 충전량을 증발부 전체의 체적보다 더 많이 과충전해야 한다. 이러한 히트파이프의 성능 파악을 위한 실험에서 고려한 변수들은 열부하, 작동액체의 충전률, 작동온도 등이며, 열수송 성능의 지표로서는 유효열전도율과 열저항을 이용하였다. 중온범위에서 적정한 작동온도를 성취하기 위해 실험에서는 전압 조절기로 열부하를 조절하는 동시에 항온조로 응축부의 냉각수 입구 온도를 제어하였다. 하나의 히트파이프에 대해서 최대 1 kW까지의 열부하에서 냉각수 입구 온도를 $40^{\circ}C$에서 $80^{\circ}C$ 범위로 변화시키면 히트파이프 작동온도를 약 $250^{\circ}C$ 내외로 조절 가능하였다. 히트파이프 작동액체 충전률은 윅구조물의 공극 체적을 기준으로 372%에서 420%까지 변화 시켰다. 실험 결과를 토대로 열저항과 유효 열전도율을 각각 입력 열유속, 작동온도, 작동액체 충전률 등의 함수로 제시했다. 동일한 냉각수 온도에서는 충전률이 높을수록 히트파이프의 작동온도가 감소하였다. 열저항 값의 범위는 최소 $0.12^{\circ}C/W$에서 최대 $0.15^{\circ}C/W$까지로 나타났으며 유효 열전도율의 값은 최소 $7,703W/m{\cdot}K$에서 최대 $8,890W/m{\cdot}K$까지 변화했다. 최소 열저항은 충전률 420%인 경우에 나타났는데 이때의 작동온도는 약 $262^{\circ}C$이었다. 히트파이프의 작동한계로서 드라이아웃(dry-out)은 충전률 372%의 경우에 열부하 950 W에서 발생하였으나, 그 이상의 충전률에서는 열부하 1060 W까지 작동한계 발생이 관찰되지 않았다. 실험 결과 본 연구에서의 히트파이프는 중온 태양열 축열조에 적용되어 개당 약 1 kW의 열부하를 이송하면서 축열물질 및 축방열 대상 유동매체와 열교환을 하는데 사용하는데 충분할 것이라 판단된다.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.409-415
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• 2018

The development of smart devices has brought about significant changes in daily life and one of the most significant changes is the virtual reality zone. Virtual reality is a technology that creates the illusion that a 3D high-resolution image has already been created using a display device just like it does in itself. Unrealized subjects are forced to rely on audiovisual materials, resulting in a decline in the concentration of practices and the quality of classes. It used virtual reality to develop effective teaching materials for radiology students. In order to produce a video clip bridge using virtual reality, a radiology clinic was selected to conduct two exposures from July to September 2017. The video was produced taking into account the radiology and work flow chart and filming was carried out in two separate locations : in the computerized tomography unit and in the LINAC room. Prior to filming the scenario and the filming route were checked in advance to facilitate editing of the video. Modeling and mapping was performed in a PC environment using the Window XP operating system. Using two leading virtual reality camera Gopro Hero, CC pixels were produced using a 4K UHD, Adobe, followed by an 8 megapixel resolution of $3,840{\times}2,160/4,096{\times}2,160$. Total regeneration time was performed in about 5 minutes during the production of using virtual reality to prevent vomiting and dizziness. Currently developed virtual reality radiation and educational contents are being used to secure the market and extend the promotion process to be used by various institutions. The researchers will investigate the satisfaction level of radiation and educational contents using virtual reality and carry out supplementary tasks depending on the results.

• Journal of Christian Education in Korea
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• v.63
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• pp.91-120
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• 2020

This study suggests a spiritual education for the Christian family as a strategy to cope with the risky situation of the Korean Church during the Covid-19 pandemic. Today, we live in a chaotic epoch since the rapid development of the science caused the Fourth Industrial Revolution and the Covid-19 pandemic gave rise to a wide array of changes throughout the society. Korean Church in these circumstances is required to have relevant responses to the kaleidoscopic changes. Especially, not to mention the face-to-face public worship service, in the situation where the congregation members even find it difficult to meet one another in a small group, it becomes a crucial issue how Christians maintain their faith and community in the healthy spirituality. As such, viewing that Christian education within the family will become much more important, this study conducts research for familial-spiritual education. For the research, this paper, first of all, attempts to understand the era of Covid-19. It is to see what the Novel Corona Virus is and what the feature of the epoch of Covid-19 might be. Based upon the understanding, this research discusses what Christian spirituality is asked for and the orientation towards which Christian education should go on. It is particularly to say that a spiritual education for the family becomes integral. The education for the family might be possible through Bibliodrama so that this study establishes a specific model of Christian education employing Bibliodrama. The discussion above shows three academic significances. First, this paper, within the domain of Christian education, suggests an alternative research which is to solve Korean Church's diverse problems caused by Covid-19. Second, this research attempts an analytical understanding of the Covid-19 period within the Christian education area. Finally, when specific and practical research for the field of Christian education during the Covid-19 pandemic is required, this study considers that Christian education within the family is overarching, thus proposing a specific model for familial-spiritual education hiring Bibliodrama.