• 한국학교보건학회지
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• 제15권2호
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• pp.205-218
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• 2002

Objectives : Because elementary school children are sensitive and prevalent to dental caries, oral health care program for the elementary school children (ESOHCP) should be met the first priority for the national oral health care program. This study was performed to proposed the guidelines for executing the efficient ESOHCP through the evaluation of present oral health care and education status based on the attitudes and opinions of health teachers. Methods : Subjects were 181 health teachers those are a part of the total 273 elementary school health teachers in Busan. From April to June 2001, questionnaire survey on the teacher's attitude and opinion, present status of oral health care and education in their own school was done. Data was analyzed by $\chi^2$-test, t-test, ANOVA using SAS (ver 6.21) program. Results : Mean age of the teachers was 40 years (24~58 years) and mean scale of the subject school was 32 classes (5~58 classes). Above 90% of them agreed with the necessity and importance of ESOHCP, but actual level of concerning was lower. They gained the informations about oral health mainly from media (33%), PC net (26%), academic society (25%), and more used internet (p=0.012) in younger generation. Though most of them (96%) had a specified school dentist, only 58% had the experience of periodic oral health examinations in their own school. The major experienced ESOHCP was fluoride brushing and contest to choose the best healthy teeth. Oral health education given by the teachers was not professional but their own. About half (42%) of the teachers had never taken education during last one year. Major education materials were VTR tape (79%), teeth model (64%), CD (55%), booklet (50%), etc., and the teachers' preference was also VTR tape (43%) and CD (41%). When they need education materials, they frequently request to dentist's association (36%), academic society (35%), but rarely to dental clinics or dentists (6%). They prefer that two times (46%) of annual oral health education, with the contents of regular brushing (53%), but lower regular visit to clinics (13%). The interest to oral health care (p=0.016) increased with teacher's age. And, they agreed regular students education in case of higher interest(p=0.044). Intention about join in the model school program was decreased with scale of school (p=0.002). Conclusions : This result showed that the present status of ESOHCP is still insufficient. It considered that the health teachers' interest and role is most important for the maintenance and success of ESOHCP. The professional and efficient education program would be focused on the health teachers to induce drive on ESOHCP.

• 한국발생생물학회지:발생과생식
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• 제9권2호
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• pp.105-114
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• 2005

배아 줄기세포는 세포 치료 목적을 위한 재료로써 매우 큰 잠재력을 가지고 있으며, 이러한 잠재력의 실현을 위해서 세포의 운명에 결정적인 역할을 하는 요소들을 확인하고 특정 세포의 대량 생산을 위한 방법을 개발하여야 한다. 조혈과정은 폭넓게 연구되어 왔으며, 배아 줄기세포로부터 조혈세포의 분화는 lineage commitment에 관한 연구에 좋은 모델이 된다. 본 연구에서는, 두 종류의 마우스 배아 줄기세포주 TC-1과 B6-1를 이용하여 그 특성과 조혈세포 분화능을 비교하여 보았다. 두 세포주는 작은 차이는 있으나 줄기세포로서의 특성을 공통적으로 가지고 있었다. 그러나 methylcellulose 배양 system을 사용하여 embryonic body 형성능을 확인한 결과 TC-1이 B6-1에 비해 월등함을 확인하였다. 조혈세포 분화의 추적을 위해 blast colony의 형성, progenitor assay, RT-PCR을 통한 조혈세포 분화 관련 marker의 발현 분석을 수행한 결과, TC-1은 정상적으로 조혈세포를 생성해 내지만, B6-1은 제대로 분화되지 못함을 확인할 수 있었다. 이러한 결과들은 in vitro에서 배아 줄기세포로부터 조혈세포로 분화를 유도할 때, 보다 적합한 세포주의 탐색이 요구됨을 제시하며 이는 향후 인간 배아 줄기세포주에서도 마찬가지로 적용될 수 있음을 암시한다고 사료된다.

• Journal of Microbiology and Biotechnology
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• 제24권8호
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• pp.1133-1142
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• 2014

Interleukin-32 (IL-32) is a cytokine and inducer of various proinflammatory cytokines such as $TNF{\alpha}$, IL-$1{\beta}$, and IL-6 as well as chemokines. There are five splicing variants (${\alpha}$, ${\beta}$, ${\gamma}$, ${\delta}$, and ${\varepsilon}$) and IL-$32{\gamma}$ is the most active isoform. We generated human IL-$32{\gamma}$ transgenic (IL-$32{\gamma}$ TG) mice to express high level of IL-$32{\gamma}$ in various tissues, including immune cells. The pathology of sepsis is based on the systemic inflammatory response that is characterized by upregulating inflammatory cytokines in whole body, particularly in response to gram-negative bacteria. We investigated the role of IL-$32{\gamma}$ in a mouse model of experimental sepsis by using lipopolysaccharides (LPS). We found that IL-$32{\gamma}TG$ mice resisted LPS-induced lethal endotoxemia. IL-$32{\gamma}$ reduced systemic cytokines release after LPS administration but not the local immune response. IL-$32{\gamma}TG$ increased neutrophil influx into the initial foci of the primary injected site, and prolonged local cytokines and chemokines production. These results suggest that neutrophil recruitment in IL-$32{\gamma}TG$ occurred as a result of the local induction of chemokines but not the systemic inflammatory cytokine circulation. Together, our results suggest that IL-$32{\gamma}$ enhances an innate immune response against local infection but inhibits the spread of immune responses, leading to systemic immune disorder.

• Geomechanics and Engineering
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• 제13권2호
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• pp.333-352
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• 2017

A comparison study is made between the dynamic properties of an argillaceous siltstone and its grouting-reinforced body. The purpose is to investigate how grout injection can help repair broken soft rocks. A slightly weathered argillaceous siltstone is selected, and part of the siltstone is mechanically crushed and cemented with Portland cement to simulate the grouting-reinforced body. Core specimens with the size of $50mm{\times}38mm$ are prepared from the original rock and the grouting-reinforced body. Impact tests on these samples are then carried out using a Split Hopkinson Pressure Bar (SHPB) apparatus. Failure patterns are analyzed and geotechnical parameters of the specimens are estimated. Based on the experimental results, for the grouting-reinforced body, its shock resistance is poorer than that of the original rock, and most cracks happen in the cementation boundaries between the cement mortar and the original rock particles. It was observed that the grouting-reinforced body ends up with more fragmented residues, most of them have larger fractal dimensions, and its dynamic strength is generally lower. The mass ratio of broken rocks to cement has a significant effect on its dynamic properties and there is an optimal ratio that the maximum dynamic peak strength can be achieved. The dynamic strain-softening behavior of the grouting-reinforced body is more significant compared with that of the original rock. Both the time dependent damage model and the modified overstress damage model are equally applicable to the original rock, but the former performs much better compared with the latter for the grouting-reinforced body. In addition, it was also shown that water content and impact velocity both have significant effect on dynamic properties of the original rock and its grouting-reinforced body. Higher water content leads to more small broken rock pieces, larger fractal dimensions, lower dynamic peak strength and smaller elastic modulus. However, the water content plays a minor role in fractal dimensions when the impact velocity is beyond a certain value. Higher impact loading rate leads to higher degree of fragmentation and larger fractal dimensions both in argillaceous siltstone and its grouting-reinforced body. These results provide a sound basis for the quantitative evaluation on how cement grouting can contribute to the repair of broken soft rocks.

• Steel and Composite Structures
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• 제34권5호
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• pp.681-698
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• 2020

The paper addresses contribution to the modeling and optimization of major machinability parameters (cutting force, surface roughness, and tool wear) in finish dry hard turning (FDHT) for machinability evaluation of hardened AISI grade die steel D₃ with PVD-TiN coated (Al₂O₃-TiCN) mixed ceramic tool insert. The turning trials are performed based on Taguchi's L₁₈ orthogonal array design of experiments for the development of regression model as well as adequate model prediction by considering tool approach angle, nose radius, cutting speed, feed rate, and depth of cut as major machining parameters. The models or correlations are developed by employing multiple regression analysis (MRA). In addition, statistical technique (response surface methodology) followed by computational approaches (genetic algorithm and particle swarm optimization) have been employed for multiple response optimization. Thereafter, the effectiveness of proposed three (RSM, GA, PSO) optimization techniques are evaluated by confirmation test and subsequently the best optimization results have been used for estimation of energy consumption which includes savings of carbon footprint towards green machining and for tool life estimation followed by cost analysis to justify the economic feasibility of PVD-TiN coated Al₂O₃+TiCN mixed ceramic tool in FDHT operation. Finally, estimation of energy savings, economic analysis, and sustainability assessment are performed by employing carbon footprint analysis, Gilbert approach, and Pugh matrix, respectively. Novelty aspects, the present work: (i) contributes to practical industrial application of finish hard turning for the shaft and die makers to select the optimum cutting conditions in a range of hardness of 45-60 HRC, (ii) demonstrates the replacement of expensive, time-consuming conventional cylindrical grinding process and proposes the alternative of costlier CBN tool by utilizing ceramic tool in hard turning processes considering technological, economical and ecological aspects, which are helpful and efficient from industrial point of view, (iii) provides environment friendliness, cleaner production for machining of hardened steels, (iv) helps to improve the desirable machinability characteristics, and (v) serves as a knowledge for the development of a common language for sustainable manufacturing in both research field and industrial practice.

• 산경연구논집
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• 제10권6호
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• pp.29-37
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• 2019

Purpose - This study intends to analyze Chinese consumers' purchase intention of Korean automobile. The aims of this study investigated to find out how product attributes and brand image affect the consumer's purchase intention of Korean automobiles in China. We consider the product attributes, brand image as evaluation criteria, also recognized as objectives for purchase intention. This study aims to analyze the positive effects on Chinese consumers' purchase intention with the variables by using the research model. Research design, data, and methodology - Based on theory of Purchase Intention, the concept of purchase intention was assessed by two factors: a) product attributes, and b) brand image to test the proposed hypotheses. The survey was conducted for 30 days, from October 17 to November 16 in 2018. With IBM SPSS Statistics 23.0 and IBM SPSS AMOS 23.0, factor analysis and regression, Cronbach's alpha and correlation were tested. 300 samples were used for this analysis. Results - As a main result, product attributes and brand image exerted significant effects on consumer's purchase intention. Thus,

and

were supported. The results showed that the product attributes, brand image had positive effects on purchase intention. The findings of this thesis are as follows: Firstly, automobiles' quality factors were divided into two categories like product properties (price, performance, design, economy, and safety), and brand image (awareness, favorability, reliability, and familiarity). Second, it showed that product properties and brand image had positive impacts on purchase intention of consumer. Conclusions - The impact of product attributes and brand image on consumer perceived value of Korean automobiles in China can be seen as a universal psychology of consumers who trust automobile products such as high quality, technology, ets. The results offer some insights into the extended model and have important managerial implications for Korean automobile enterprise. As the findings of this thesis show, all strategic orientations have significant and positive effects on the ability of innovation. At the same time, automobile company must pay attention to quality. As the relationship between the automobiles' performance and brand image were positive and significant, automobile companies should have comprehensive strategic orientations focused on strengthening these factors.

• 한국산학기술학회논문지
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• 제18권3호
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• pp.249-257
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• 2017

신뢰성 있는 통행시간 예측을 위해 DSRC로부터 수집된 통행시간에서의 이상치(outlier) 필터링은 필수이다. 통행시간 예측을 위해 사용되는 보편적 기법인 TRANSGUIDE는 특정 분석 시간동안 통행시간의 변동이 크게 발생하는 조건에서 수집데이터의 이상치 제거를 효율적으로 처리하지 못하는 문제점이 존재한다. 이에 본 연구에서는 TRANSGUIDE의 한계점 을 보완할 수 있는 알고리즘을 제안하고자 한다. TRANSGUIDE가 특정 분석 시간대 충분한 데이터 관측이 어려울 경우 Median Absolute Deviation(MAD)를 이용하여 이상치 제거를 위한 새로운 유효 분석 영역을 설정하였다. 새로운 분석 영역 설정 후 특정 시간대 교통 조건하에서 최대 허용 가능한 이상치를 고려한 변수 ${\alpha}$, ${\beta}$를 제안하였다. 변수 ${\alpha}$, ${\beta}$를 추정하기 위해 과거 데이터와 도로 구간의 특성을 반영하였다. 개발된 알고리즘은 수도권 일반국도 3호선, 2013년 1월 1달간 DSRC 데이터가 존재하는 다차로 일반국도에 적용하였다. 누적상대도수를 이용하여 모형의 정산 수행 후 성능에 대해 정량적 평가를 수행하였다. 개발된 알고리즘은 기존의 TRANSGUIDE가 특정 조건, 즉 일정 분석 시간동안 교통 조건이 급하게 변동되는 구간에서 이상치 제거에 취한한 점을 보완하는 것으로 판단되었다. TRANSGUDIDE가 특정 조건에서 통행시간 예측이 어려울 경우 본 개발 알고리즘은 활용될 것으로 판단한다.

• 한국수자원학회논문집
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• 제47권10호
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• pp.891-906
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• 2014

본 연구는 수계관리 측면에서 물 공급의 기준이 되는 하류 제어지점에서 발생할 수 있는 물 부족을 최소 허용하면서 저수지군 최적 운영방안을 제공할 수 있도록 위험도 평가기준을 목적함수 및 제약조건에 반영한 hedging rule을 혼합정수계획법(MIP, Mixed Integer Programming)으로 구성하고 이에 대한 이행도를 분석함으로써 기존의 용수공급 신뢰도에 중점을 두었던 저수지군 최적 운영 분석기법을 개선하고자 하였다. 이를 위해 한강수계 5개 저수지(소양강댐, 충주댐, 화천댐, 청평댐, 팔당댐)군을 대상으로 수계관리를 위한 모형을 구축하였으며, 한강수계 내에 총 8개의 가상 제어지점을 구성하여 댐 하류 제어지점에서의 물 부족에 대해 위험도를 평가하였으며, 개발된 hedging rule의 적정성을 검증하기 위하여 2개의 유입량 계열('93. 1월~'97. 12월, '99. 1월~'03. 12월)에 대하여 적용 검토하였다. 팔당댐 하류 제어지점의 월별 최소유량을 비교하면 '93. 1월~'97. 12월의 모의기간에서는 hedging rule 적용 시 $317.5{\times}10^6m^3$으로 단독운영의 $310.6{\times}10^6m^3$, 연계운영의 $56.3{\times}10^6m^3$ 보다 많은 유량을 보였으며, '99. 1월~'03. 12월의모의기간에서도 hedging rule 적용시 $243.7{\times}10^6m^3$ 으로 단독운영의 $204.2{\times}10^6m^3$, 연계운영의 $111.2{\times}10^6m^3$에 비해 최소 유량이 많은 것을 확인하였으며, 이는 제안한 hedging rule에 의해 하류 제어지점에서의 최대 물 부족량이 감소하는 결과를 보여주고 있다.

• 한국도로학회논문집
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• 제7권4호
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• pp.41-47
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• 2005

교통량, 속도, 차종 등으로 대표되는 교통자료는 도로를 계획하고 설계하는데 있어 매우 중요한 기초자료로 활용된다. 교통자료를 기준으로 해당 도로의 장래 서비스수준을 예측하며, 신설 및 확장될 도로의 기하구조가 결정되기 때문이다. 1985년 이후부터 건설교통부에서는 일반국도에 대해서 수시 교통량 조사와 상시 교통량 조사를 병행하고 있다. 이러한 교통조사는 일반국도와 일반국도 또는 일반국도와 고속국도가 만나는 네트웍 상의 노드를 중심으로 교통조사 구간을 설정하고, 이들 교통조사 구간에 대해서 교통량 조사를 수행하고 있다. 이러한 교통조사구간 설정 방법은 주요 도로가 만나는 결절점 사이의 구간에서는 교통량 변화패턴이 유사하다는 것을 전제로 하고 있다. 최근 우회도로의 신설, 중앙분리대 설치 등의 도로 기하구조 및 교통 시설물의 설치로 인하여 기존 구간의 특성이 변화되었다. 따라서 전국 일반국도를 대상으로 교통조사 구간의 유사성을 평가하여 국도의 동질성 구간에 대한 분석을 수행하였다. 유사성 평가를 위해서는 유전자 알고리즘을 적용한 모형을 구축하고, 모형의 적용을 통해 교통조사 구간을 정의하였다.

• 한국지반공학회논문집
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• 제30권6호
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• pp.5-21
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• 2014

지진시 불포화 도로성토의 붕괴는 지하수 및 강우의 침투에 기인한 함수비의 증가가 그 원인이 됨이 지적되어 왔다. 따라서, 이와 같은 지반재해의 방지를 위한 합리적 보강방안 및 적절한 설계기준의 정립을 위해 불포화 도로성토의 동적안정성 및 변형모드에 대한 함수비의 영향을 연구할 필요가 있다. 본 연구에서는 불포화 도로성토의 변형 및 파괴거동에 대한 함수비의 영향을 연구하기 위해 상이한 함수비를 갖는 도로성토 모형에 대하여 동적 원심모형실험을 진행하였다. 본 실험에서는 도로성토 모형에 대한 동적하중 부가시의 변위, 간극수압 및 가속도의 계측을 통해 최적함수비 부근 및 최적함수비보다 높은 함수비를 갖는 불포화 도로성토에 대한 동적 거동을 고찰하였다. 이와 함께, 화상해석에 의한 변위 및 변형율 분포의 분석을 통하여 최적함수비보다 높은 함수비를 갖는 불포화 도로성토의 변형모드를 구명하였다. 이로부터 사면 천단부의 침하는 천단부 아래에서의 체적압축에 기인하며, 구속압력이 작은 사면 선단부 및 사면 표면부 부근에서는 체적팽창을 동반한 큰 전단변형이 발생함을 확인하였다.