• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권5호
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• pp.328-334
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• 2020

Objectives: This study aimed to validate the effectiveness of a recently proposed difficulty index for removal of impacted mandibular third molars based on extraction time and suggest a modified difficulty index including the presence of pathologic conditions associated with third molars. Materials and Methods: This retrospective study enrolled 65 male patients younger than 25 years with third molars. Extraction time was calculated from start of the incision to the last suture. The difficulty scores for third molars were based on spatial relationship (1-5 points), depth (1-4 points), and ramus relationship (1-3 points) using cone-beam computed tomography. The difficulty index was defined as follows: I (3-4 points), II (5-7 points), III (8-10 points), and IV (11-12 points). The modified difficulty score was calculated by adding one point to the difficulty score if the third molar was associated with a pathologic condition. Two modified difficulty indices, based on the presence of pathologic conditions, were as follows: the half-level up difficulty index (HDI) and the one-level up difficulty index (ODI) from the recently proposed difficulty index. Results: The correlations between extraction time and difficulty index and or modified difficulty indices were significant (P<0.001). The correlation coefficient between extraction time and difficulty index was 0.584. The correlation coefficients between extraction time and HDI and ODI were 0.728 and 0.764, respectively. Conclusion: Extraction time of impacted third molars exhibited a moderate correlation with difficulty index and was strongly correlated with the modified indices. Considering the clinical implications, the difficulty index of surgical extraction should take into consideration the pathologic conditions associated with third molars.

• 벤처창업연구
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• 제13권2호
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• pp.15-26
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• 2018

본 연구는 실패 이후, 재창업을 하는 기업인들을 대상으로 실패 경험, 재창업 동기, 정부지원사업경험과 재창업교육 등이 재창업기업성과에 미치는 영향과 함께, 상기 4가지 요인들이 채무/신용문제에 따라 재창업기업성과에 미치는 영향이 어떻게 변하는지 분석하였다. 분석결과 실패경험은 재창업기업성과에 유의미한 영향이 없게 나타난 반면, 재창업동기와 정부지원사업경험 그리고 재창업교육은 재창업기업성과에 유의미한 영향을 미치고 있었다. 한편, 신용문제를 고려한 분석에서는 상기 4가지 요인들 모두 신용문제의 유무에 따라 재창업기업 성과에 서로 다른 영향을 보이고 있다. 신용문제가 없는 재창업 그룹에서 재창업동기와 실패경험이 재창업기업성과에 유의미한 영향을 미치고 있는 반면, 신용문제가 있는 재창업 그룹에서는 정부지원사업경험과 재창업교육 참여가 재창업기업성과에 유의미한 영향을 미치고 있었다. 본 연구결과 첫째, 신용문제 유무에 따라 재창업기업성과에 영향을 미치는 요인들이 다르다는 것을 보여주고 있다. 이는 실패 및 재창업 관한 연구 뿐 아니라, 재창업 정책 개발을 함에 있어 신용문제에 따른 차별적 접근이 필요하다는 점을 말하고 있으며, 둘째, 실패경험이 재창업기업성과에 영향이 없게 나온 것은 폐업 후 재창업까지 소요되는 기간 (평균 56개월, 단, 경우에 따라 2년~ 7년 이상이 소요)이 실패경험이 자산화되는데 영향이 미칠 수 있기 때문이라는 것을 추정 할 수 있었다. 이는 기존 연구에서 다루지 않았던 부분으로 향후, 실패경험과 재창업에 대한 직/간접 영향을 연구하고, 정책을 수립할 때, 진부화라는 개념에서 실패 이후 재창업까지 소요되는 기간을 고려해야 할 필요성을 제시하고 있다.

• International Journal of Oral Biology
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• 제31권2호
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• pp.53-65
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• 2006

Calcium concentration in the bone resorption lacunae is high and is in the mM concentration range. Both osteoblast and osteoclast have calcium sensing receptor in the cell surface, suggesting the regulatory role of high extracellular calcium in bone metabolism. In vitro, high extracellular calcium stimulated osteoclastogenesis in coculture of mouse osteoblasts and bone marrow cells. Therefore we examined the genes that were commonly regulated by both high extracellular calcium and $1,25(OH)_2vitaminD_3(VD3)$ by using mouse oligo 11 K gene chip. In the presence of 10 mM $[Ca^{2+}]e$ or 10 nM VD3, mouse calvarial osteoblasts and bone marrow cells were co-cultured for 4 days when tartrate resistant acid phosphatase-positive multinucleated cells start to appear. Of 11,000 genes examined, the genes commonly regulated both by high extracellular calcium and by VD3 were as follows; 1) the expression of genes which were osteoclast differentiation markers or were associated with osteoclastogenesis were up-regulated both by high extracellular calcium and by VD3; trap, mmp9, car2, ctsk, ckb, atp6b2, tm7sf4, rab7, 2) several chemokine and chemokine receptor genes such as sdf1, scya2, scyb5, scya6, scya8, scya9, and ccr1 were up-regulated both by high extracellular calcium and by VD3, 3) the genes such as mmp1b, mmp3 and c3 which possibly stimulate bone resorption by osteoclast, were commonly up-regulated, 4) the gene such as c1q and msr2 which were related with macrophage function, were commonly down-regulated, 5) the genes which possibly stimulate osteoblast differentiation and/or mineralization of extracellular matrix, were commonly down-regulated; slc8a1, admr, plod2, lox, fosb, 6) the genes which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were commonly up-regulated; s100a4, npr3, mme, 7) the genes such as calponin 1 and tgfbi which possibly suppress osteoblast differentiation and/or mineralization of extracellular matrix, were up-regulated by high extracellular calcium but were down-regulated by VD3. These results suggest that in coculture condition, both high extracellular calcium and VD3 commonly induce osteoclastogenesis but suppress osteoblast differentiation/mineralization by regulating the expression of related genes.

• 한국농촌건축학회논문집
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• 제24권1호
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• pp.27-36
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• 2022

Currently the population of rural areas in Korea continue to decline due to low birth rate, aging population, and migration. This phenomenon is accelerated over time. And as a result, there are some declining phenomenon in rural society. And it is same in the residential and basic living conditions of rural villages. The increase ratio of empty houses exacerbates the rural landscape, acts as a cause of crime and bring out various social and economic problems such as worsening settlement conditions and local slums. The study is carried out to prevent this phenomenon by investigating the architectural contents of empty houses in the village, surveyed residents and owners and finally analyzed and synthesized to make a plan to utilize empty houses in the village. This study was conducted from June to December 2021. The conclusions are followings: 1. The empty houses in Korea were 1,511 million in 2020, 8.2% of the total number of houses, whereas those in Jeollabuk-do were 95,412, 12.9% of those of houses, and those in Gimje-city, the subject of this study, were 5,944. It is up to 15.8%. In particular, empty houses in Hacheon village, the site of this study, accounted for the highest ratio, with 25% of the total number of houses. 2. To understand the utilization and improvement of empty houses, surveys and interviews were conducted to residents and owners of Hacheon village in Gimje, and most of the residents submit proposals that empty houses were not desirable in terms of village landscape and safety. The owners don't have intentions of selling or leasing them. They want to remodel them and rent for a specific period. 3. As the physical condition of the empty houses(9empty houses) 6 empty houses of them are good. 4 of them are in poor condition. 4. By synthesizing these contents, nine empty houses in Hacheon village will be remodeled as the space for those of rural start-up young people, smart farm area, community space and rental housings for rural returnees.

• 벤처창업연구
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• 제18권2호
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• pp.35-52
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• 2023

최근 코로나19, 환경오염 등으로 비대면 환경이 전개되면서 온라인 디지털 헬스케어의 중요성이 커지고 있으며 관련하여 건강관리, 원격진료, 디지털 치료제 등의 벤처창업 및 활동도 활발히 진행되고 있다. 본 연구는 디지털 헬스케어 스마트워치 수용성에 미치는 영향을 확장된 통합기술수용모형(UTAUT2)과 행동추론모형(BRT)의 통합적 접근으로 진행하였다. 첨단 ICT와 의료가 융합된 디지털 헬스케어에 적합한 요인 발굴은 혁신기술 수용연구에 가장 진보적으로 평가받는 확장된 통합기술수용모형을 활용하여 효용기대, 사회영향, 사용편의, 가격장벽, 대안부족, 이용장벽 등의 주요 요인을 도출하였고, 소비자의 가치-이유-태도-행동의도를 일괄 검증 할 수 있으면서 수용이유뿐만 아니라 비수용이유-소비자 스마트워치 디지털 헬스케어 인식의 긍정적 측면뿐만 아니라 부정적 측면까지-분석 할 수 있는 행동추론모형을 활용하여 인과관계 영향과 크기를 검증하였다. 연구를 위해 전국에 있는 10대에서 60대에 이르는 일반인을 대상으로 약 410여건의 설문 응답을 취합하여 이를 바탕으로 데이터에 대한 신뢰성 및 타당성 검정을 거쳐 구조방정식을 이용하여 가설을 검증하였다. 연구 분석에는 SPSS 23, AMOS 23 등을 활용하였다. 연구 결과, 개인혁신성은 수용이유(효용가치, 사회영향, 사용편의), 태도, 비수용이유(가격장벽, 대안부족, 이용장벽)에 유의미한 영향을 미치는 것으로 나타났다. 이러한 결과는 혁신된 ICT의 주요 가치의 사용자 수용의도에의 영항을 확인한 선행연구 연구결과와 동일하다. 그리고 수용이유는 태도에 유의미한 영향을 미치나 비수용이유의 영향은 유의하지 않은 것으로 나타났다. 이는 소비자들이 ICT 신제품·신규서비스에는 관심이 크지만 이의 구입은 보다 신중하게 선택적으로 한다고 보여 진다. 본 연구는 학술적으로는 기존의 소비자 범용 혁신기술 수용성 분석을 새롭고 향후 중요분야인 스마트워치 디지털 헬스케어 분야의 소비자 가치 수용성 분석으로 발전시켰으며 확장된 통합기술수용모형과 행동추론모형의 장점을 살려 통합적으로 실행한 점 등이 있겠으며, 산업적으로는 기존 소비자의 수용성 이유 분석 중심에서 소비자 수용·비수용 이유 통합 검증으로 스마트워치를 구매하는 이유뿐만 아니라 구매하지 않는 이유까지 분석하여 제품·서비스 기획, 개발, 마케팅에 기여 할 수 있게 했다는 점 등이 있겠다. 본 연구가 향후 우리 생활에 중요한 역할을 할 디지털 헬스케어 분야의 연구 증대에 기여 할 수 있기 바라며 또한 본 연구와 같은 통합적 접근 모형과 소비자 수용·비수용 이유 통합 분석 등을 통하여 혁신과 향후 관련 연구들이 좀 더 소비자 가치에 적합한 심도 있는 요인 발굴과 검증으로 발전하기를 기대한다.

• 산업경영시스템학회지
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• 제39권4호
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• pp.7-14
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• 2016

Unlike most researches that focus on single manufacturer or single buyer, this research studies the cooperation policy for two participants of supply chain such as single vendor and single buyer. Especially, this paper deals with single vendor-single buyer integrated-production inventory problem. If the buyer orders products, then the vendor will start to make products and then the products will be shipped from the vendor to the buyer many times. The buyer is supposed to order again when the buyer's inventory level hits reorder point during the last shipment and this cycle keeps repeated. The buyer uses continuous review inventory policy and customer's demand is assumed to be probabilistic. The contribution of this paper is to present a mixed approach and derive its cost function. The existing policy assumes that the size of shipping batch from single vendor to single buyer is increasing, called Type 1, or constant, called Type 2. In mixed approach, the size of shipping batch is increasing at the beginning part of the cycle, and then its size is constant at the ending part of the cycle. The number of shipping for Type 1 and Type 2 in a cycle in mixed approach is determined to minimize total cost. The relationship between parameters, for example, the holding cost per product, the set up cost per order, and the shortage cost per item and decision variables such as order quantity, safety factor, the number of shipments, and shipment increasing factor is figured out via sensitivity analysis. Finally, it is statistically proved that the mixed approach is superior to the existing approaches.

• 한국분무공학회지
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• 제23권3호
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• pp.122-127
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• 2018

Recently, registrated passenger cars have increased and were close about seventy million at the end 2017 year in Korea. Among the passenger car using gasoline fuel make up forty six percentage of total registrated vehicles. In this study, investigation on real driving emission characteristics in the passenger car using gasoline fuel with various engine displacements were carried out. The real driving emission characteristics were measured and analyzed by using PEMS (Portable Emission Measurement System). PEMS was composed of gas analyzer, emission flow meter and sample conditioning system et al. Also, test six vehicles were selected to the gasoline passenger car with engine displacement from 1.6L to 3.7L. Two test routes with engine start of cold and hot conditions were applied to analyze the emission characteristics of RDE, respectively. The results show that the $CO_2$ emission have a increasing trend as the engine displacement and vehicle weight. Also, it is guessed that the $CO_2$ emission and vehicle weight were more correlated than the engine displacements. On the other hand, NOx emissions of RDE have not increasing or decreasing tendency according engine displacements or vehicle weight because the activation of three-way catalyst in the gasoline vehicles.

• 한국환경과학회지
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• 제1권2호
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• pp.125-136
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• 1992

Digestion of a municipal wastewater sludge by the anaerobic sequencing batch reactor (ASBR) was investigated to evaluate the performance of the ASBR process at a critical condition of high-solids-content fined. The reactors were operated at an HRT of 10 days with an equivalent loading rate of 0.8-1.5 gVS/L/d at 35$^{\circ}C$ The main conclusions drawn from this study were as follows: 1. Digestion of a municipal wastewater sludge was possible using the ASBR in spite of high concentration of settleable solids in the sludge. The ASBRS with 3- and 4-day cycle period showed almost identical high digestion performances. 2. No adverse effect on digestion stability was observed In the ASBRS in spite of withdrawal and replenishment of 30% or 40% of liquid contents. A conventional anaerobic digester could be easily converted to the ASBR without any stability problem. 3. Flotation thickening occurred in thicken step of the ASBRS throughout steady state, and floating bed volume at the end of thicken period occupied about 70% of the working volume of the reactor Efficiency of flotation thickening in the ASBRS could be comparable to that of additional gravity thickening of a completely mixed digester. 4. Solids were accumulated rapidly in the ASBR during start-up period. Solids concentrations in the ASBRS were 2.6 times higher than that in the completely mixed control reactor at steady state. Dehydrogenase activity had a strong correlation with the solids concentration. Dehydrogenase activity of the digested flu형e in the ASBR was 2.9 times higher than that of the flu형e in the control reactor, and about 25 times higher than that of the subnatant in the ASBR. 5. Remarkable increase in equivalent gas production of 52% was observed at the ASBRS compared with the control reactor in spite of similar quality of clarified effluent from the ASBRS and control reactor. The increase in gas production from the ASBRS was believed to be combined results of accumulation of microorganisms, higher driving force applied, and additional long-term degradation of organics continuously accumulated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.291-295
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• 2007

FTL(Fuel Test Loop) is a facility that confirms performance of nuclear fuel at a similar irradiation condition with that of nuclear power plant. FTL consists of In-Pile Test Section (IPS) and Out-Pile System (OPS). FTL construction work began on August, 2006 and ended on March, 2007. During Construction, ensuring the worker's safety was the top priority and installation of the FTL without hampering the integrity of the HANARO was the next one. Task Force Team was organized to do a construction systematically and the communication between members of the task force team was done through the CoP(community of Practice) notice board provided by the Institute. The installation works were done successfully overcoming the difficulties such as on the limited space, on the radiation hazard inside the reactor pool, and finally on the shortening of the shut down period of the HANARO. Without a sweet of the workers of the participating company of HEC(Hyundae Engineering Co, Ltd), HDEC(HyunDai Engineering & Construction Co. Ltd), equipment manufacturer, and the task force team, it is not possible to install the FTL facility within the planned shutdown period. The Commissioning of the FTL is on due to check the function and the performance of the equipment and the overall system as well. The FTL shall start operation with high burn up test fuels in early 2008 if the commissioning and licensing progress on schedule.

• Journal of Chest Surgery
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• 제28권6호
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• pp.542-548
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• 1995

The goal of this study is to develop an effective control system for cardiac output regulation based upon the preload and afterload conditions without any transducers and compliance chambers in the moving actuator type total artificial heart. Motor current waveforms during the actuator movement are used as an input to the automatic control algorithm. While the current waveform analysis is performed, the stroke length and velocity of the actuator are gradually increased up to the maximum pump output level. If the diastolic filling rate of either right or left pump begins to exceed the venous return, atrial collapse will occur. Since the diastolic suction acts as a load to the motor, this critical condition can be detected by analyzing the motor current waveforms. Every time this detection criterion is met, the control algorithm decreases the stroke velocity and length of the actuator step by step just below the critical detection level. Then, they start to increase. In this way the maximum pump output under given venous return can be achieved. Additionally the control algorithm provides some degree of afterload sensitivity. If the aortic pressure is detected to exceed 120 mmHg, the stroke length and velocity decrease in the same way as the response to the preload. Left-right pump output balance is maintained by proper adjustment of the asymmetry of the stroke angle. In the mock circulatory test, this control system worked well and there was a considerable range of stroke volume difference with adjustment of the asymmetry value. Two ovine experiments were performed. It was confirmed that the required cardiac output regulation according to the venous return could be achieved with adequate detection of diastolic function, at least in the in vivo short-term survival cases[2-3 days . We conclude that this control algorithm is a promising method to regulate cardiac output in the moving actuator type total artificial heart.