• 한국임상보건과학회지
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• 제2권4호
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• pp.239-246
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• 2014

Purpose. to describe the prevalence of refractive error according to aging in young children in South Korea. Methods : From July 2013 to June 2014, five hundred subjects( 250 male subjects, 250 female subjects; aged between 7 and 12 years) were performed in refraction test using the Auto-Refraction. Myopia, hyperopia, astigmatism, and anisometropia were defined as spherical equivalent(SE)${\leq}-0.50$ diopters, SE ${\geq}+2.00$ D, cylinder error ${\geq}0.75$ D and SE difference${\geq}1.00$ D between binocular eyes, respectively. Results. The refractive error by spherical equivalent among all subjects was myopia 80.41%, astigmatism 44.89%, emmetropia 18.27%, anisometropia 16.92%, and hyperopia 1.32%. The prevalence of myopia increased with age. but hyperopia was decrease. Myopia and astigmatism were much more common in male than females although the difference was not statically significant. Emmetropia and hyperopia were much more common in female than males although the difference was not statically significant. The prevalence of spherical equivalent was much common from -1.00 diopter to 0.99 diopter. On the other hand, the prevalence of myopia was much more than hyperopia. There was a statistical significance between 9 year and 10 year of female in the spherical equivalent power(p>0.05). In all another group of age, there was not a statistical significance as aging in spherical equivalent power(p>0.5). However, there was a statistical significance between male and female as age in the spherical equivalent power(P>0.01). Conclusions: Myopia was the most common refractive error in Korea young children, while hyperopia was decreased after 7 years. There was a statistical significance as age between male and female at spherical equivalent power(P> 0.01). these results suggested that the analysis of the refractive error as age at young children can give the useful diagnosis data for the correction of visual function.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.148-151
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• 2005

This paper is concerned with the thermo-mechanical behavior and temperature dependent strain rate sensitivity of steel sheet for an auto-body. In order to Identify the temperature dependent strain rate sensitivity of SPRC35R and SPRC45E, uniaxial tension tests are performed with the variation of the strain rates from 0.001/sec to 200/sec, and the variation of environmental temperatures from $-40^{\circ}C\;to\;200^{\circ}C$. The thermo-mechanical response at the quasi-static state is obtained with the static tensile test and at the intermediate strain rate is from the high speed tensile test. The experimental results show that the strain rate sensitivity increases at low temperature and it decreases at high temperature. It means that as the strain rate getting increasing, the variation of flow stress is more sensitive on the temperature. The results also indicates that the material properties of SPRC35R is more depend on the changes of strain rates and temperature than those of SPRC45E.

• 소성∙가공
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• 제15권2호
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• pp.132-137
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• 2006

This paper is concerned with the thermo-mechanical behavior including temperature dependent strain-rate sensitivity of steel sheet for an auto-body. In order to identify the temperature dependent strain-rate sensitivity of SPRC35R and SPRC45E, uniaxial tension tests are performed with the variation of the strain-rates from 0.001 /sec to 200 /sec at environmental temperatures varied from $-40^{\circ}C\;to\;200^{\circ}C$. The thermo-mechanical response at the quasi-static state is obtained with the static tensile test and at the intermediate strain-rate is from the high speed tensile test. Experimental results show that the strain-rate sensitivity increases at low temperature. It represents that as the strain-rate increases, the variation of flow stress becomes sensitive on the temperature. The results indicate that the flow stress of SPRC35R is more dependent on the changes of strain-rate and temperature than those of SPRC45E.

• 자동차안전학회지
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• 제13권3호
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• pp.102-110
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• 2021

As an alternative to solving safety, environments, and aging problems, ADS (Automated driving system) in the global automotive market is actively being developed as a new growth industry. In time for the appearance of ADS, relevant regulations and assessment programs must also be developed. For example, safety standards for the Level 3 automated driving system were promulgated in December 2019 by the Ministry of Land, Infrastructure and Transport of Korean government. However, assessment programs such as KNCAP for autonomous functions of ADS have not yet been introduced in Korea as well as globally. The autonomous driving functions of ADS at Level 3 or higher must be capable to recognize, judge and respond to objects and events in a wide variety of complex situations. In this paper, we examined and studied the complex situations, considerations and assessment items that ADS must respond to in the interest of safety for passengers, pedestrians and other road users. We hope this paper will be helpful to develop an execution program in the future.

• International Journal of Safety
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• 제11권1호
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• pp.11-14
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• 2012

Hazard of Biodiesel (BDF) was studied. Biodiesel is a name for a variety of ester-based fuel made from vegetable oils. Recently importance of biodiesel is increasing, and its fires were sometimes reported. Therefore we studied on hazard of biodiesel comparing (petroleum) diesel oil and vegetable oil, raw materials of biodiesel. We found that biodiesel is auto-oxidized easily and ignites, and its flash point decreases when even small amount of methanol exists. And there are various raw materials to manufacture biodiesel, so we studied the difference of these materials, and their aging on safety.

• 한국식품과학회지
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• 제39권4호
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• pp.432-437
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• 2007

김치의 최적 숙성 및 장기저장을 위한 김치냉장고에서의 발효, 저장조건을 연구하기 위하여 온도별(5, 10, 15, $20^{\circ}C$)로 김치의 이화학적${\cdot}$관능적 특성 검사를 하여 S사 김치냉장고의 자동숙성 mode($23^{\circ}C$에서 25시간 후 $-1^{\circ}C$ 자동전환)에서 발효시킨 김치와 비교하였다. 김치 냉장고 초기 발효 온도 설정에 관한 연구결과 발효 적숙기에 도달하는 시간, 적숙기 기간 및 김치 맛을 종합적으로 고려하였을 때, 김치냉장고 초기 발효 온도는, $10-15^{\circ}C$가 적절한 것으로 나타났다. 김치냉장고의 초기 발효시간을 결정하기 위하여 $10^{\circ}C$와 $15^{\circ}C$에서 김치를 산도 $0.4{\pm}0.05$, $0.6{\pm}0.05$ 그리고 $0.8{\pm}0.05%$에 도달할 때까지 발효시킨 후 즉시 $-1^{\circ}C$에서 7일간 저장한 후 산도 변화와 김치 맛을 종합적으로 살펴본 결과 특정산도에 도달하는 시간은 $15^{\circ}C$가 산도 0.4%에서 $-1^{\circ}C$로 저장한 김치의 경우 신맛, 새콤한 맛 그리고 종합적인 평가 점수는 올라갔으며, 덜 익은 맛의 강도가 크게 낮아졌다. 그러나 산도가 0.6% 및 0.8% 에서 $-1^{\circ}C$로 저장한 김치의 관능평가의 종합 점수는 낮아졌고, 군덕 맛의 강도는 높아졌다. 저장온도에 대한 실험에서 기존 김치냉장고에서 사용하고 있는 $-1^{\circ}C$ 저장온도는 김치의 미생물의 발육을 완전히 억제하지 못하는 것으로 나타났고 $-2{\pm}0.5^{\circ}C$ 저장온도는 김치가 얼지 않는 최저 온도로 사료된다. 본 연구 결과 배추김치를 김치냉장고에서 자동적으로 발효${\cdot}$저장할 때 관능적 특성 및 저장기간을 극대화할 수 있는 최적 자동숙성 시스템은 $15^{\circ}C$에서 김치의 산도가 0.4%에 도달할 때까지 발효시킨 후 $-2{\pm}0.5^{\circ}C$로 온도를 전환하여 저장하는 조건으로 설정하는 것이 가장 바람직한 것으로 생각된다.

• 한국식품과학회지
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• 제40권6호
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• pp.661-668
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• 2008

동치미를 김치냉장고에서 발효 숙성시켰을 때 풍미가 우수한 동치미를 장기간 먹을 수 있는 저장 조건을 확립하고자 온도별(5, 10, 15, $20^{\circ}C$)로 동치미의 발효숙성 특성을 살펴보고 이를 삼성사 김치 냉장고의 자동숙성모드($23^{\circ}C$에서 25시간 발효 후 $-1^{\circ}C$ 자동전환)에서 발효시킨 동치미와 비교하였다. 동치미의 관능이 가장 좋은 시기는 pH는 $3.9{\pm}0.1$, 그리고 산도는 $0.25{\pm}0.05%$로 나타났으며 $10^{\circ}C$ 및 $15^{\circ}C$에서 숙성시킨 동치미가 적숙기에 빨리 도달하면서도 관능평가 점수가 높아 초기 발효 온도대는 $10-15^{\circ}C$가 적합하다는 결과를 얻었다. 이에 반해 자동숙성모드에서 저장한 동치미는 30일 경까지 적숙기에 도달하지 못하였다. 김치냉장고 초기 발효 시간을 결정하기 위하여 동치미를 $10^{\circ}C$ 및 $15^{\circ}C$에서 저장하여 산도가 0.1, 0.2 또는 0.3%에 도달하였을 때 $-1^{\circ}C$에 7일간 저장하면서 동치미의 발효 진행 및 관능검사를 실시한 결과 $10^{\circ}C$에서 발효시킨 동치미가 $15^{\circ}C$ 발효군보다 탄산미가 높고 군덕맛의 강도는 낮아 종합평가 점수가 높았다. $-1^{\circ}C$에 저장한 동치미의 산도는 1주일 동안 $0.08{\pm}0.02%$ 증가하여 저장온도 $-1^{\circ}C$에서도 미생물의 발육을 완전히 억제되지 못하는 것으로 나타났다. 본 연구 결과 동치미를 김치냉장고에서 자동으로 발효 저장할 때 동치미의 특성을 최대화할 수 있는 조건으로 $10^{\circ}C$에서 산도가 0.2%에 도달하였을 때 까지 발효시킨 후 $-2.5{\pm}0.5^{\circ}C$로 전환할 것을 제안한다. 이러한 동치미는 계절에 상관없이 탄산미와 살얼음맛을 느낄 수 있고 군덕내의 발생은 장기간 억제할 수 있을 것으로 생각된다.

• 응용통계연구
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• 제29권5호
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• pp.987-998
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• 2016

자동차 보험은 치열한 시장경쟁과 금융당국의 요율 규제로 가격 조정에 합리적인 적용 방식이 요구되는 대표적인 보험상품이다. 특히 고령화 사회로 인한 인구변화와 가격경쟁으로 인한 요율 세분화는 보험료 결정에 주요한 요인으로 작용하게 된다. 따라서 본 논문에서는 여러 가지 요율 요소 중 연령에 대한 분포 추정을 통해 가격 최적화 방안을 제시하고자 한다. 미래 분포를 추정하는 방식으로 고객의 연령이동, 신규유입, 고객이탈 3가지 요인에 대한 최적화 방안을 적용함으로써 합리적인 연령 분포를 추정하여 가격 조정 과정에 반영하고자 한다. 기존 연령 분포를 적용한 보험료와 미래 연령 분포를 추정하여 적용한 보험료를 수지 불균등 원칙에 적용하여 위험도 추정에 대한 적정성을 비교 분석하는 것이 목적이다. 보험료 인상 또는 인하 문제와는 별개로 인구변화에 대한 적정 분포를 추정함으로써 가입자의 분포 변화로 인한 결손 또는 초과 이득이 발생하지 않는 적정 보험료 추정 방식을 제안하고자 한다.

• 동의생리병리학회지
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• 제30권5호
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• pp.338-346
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• 2016

Signal transducer and activator of transcription 3 (STAT3) is associated with various human diseases, such as cancer, auto-immune disease, and intestinal inflammation. The limited and inadequate effect of standard approaches for treating inflammatory bowel disease (IBD) has prompted to develop alternative anti-colitis agents through inhibition of STAT3. Here, we show that gallic acid (GA), a 3,4,5-trihydroxybenzoic acid, markedly reduced phosphorylation of STAT3. Among the derivatives of benzoic acids, GA showed significant inhibition on STAT3 phosphorylation. In addition, GA ameliorated the dextran sodium sulfate (DSS)-induced acute colitis as determined by the measurement of symptomatic and histological indices. The suppression of DSS-induced acute colitis by GA treatment may be related to the regulation of cytokines and growth factors. Furthermore, GA inhibited phosphorylation of STAT3 in the colon tissue of DSS-treated mice. These findings may be useful in comprehending the molecular action of GA on STAT3 phosphorylation and provide novel insights into the potential application of GA in the treatment of STAT3-related inflammatory disease, such as IBD.

• 대한통합의학회지
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• 제6권4호
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• pp.149-169
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• 2018

Purpose : This study was to develop a strategy for modeling future workforce projections to serve as a basis for analyzing annual supply of and demand for physical therapists across the South Korea into 2030. Methods : In-and-out movement model was used to project the supply of physical therapists. The demand was projected according to the demand-based method which consists of four-stages such as estimation of the utilization rate of the base year, forecasting of health care utilization of the target years, forecasting of the requirements of clinical physical therapists and non-clinical physical therapists based on the projected physical therapists. Results : Based on the current productivity standards, there will be oversupply of 39,007 to 40,875 physical therapists under the demand scenario of average rate in 2030, undersupply of 44,663 to 49,885 under the demand scenario of logistic model, oversupply of 16,378 to 19,100 under the demand scenario of logarithm, and oversupply of 18,185 to 20,839 under the demand scenario of auto-regressive moving average (ARIMA) model in 2030. Conclusion : The result of this projection suggests that the direction and degree of supply of and demand for physical therapists varied depending on physical therapists productivity and utilization growth scenarios. However, the need for introduction of a professional physical therapist system and the need to provide long-term care rehabilitation services are actively being discussed in entering the aging society. If community rehabilitation programs for rehabilitation of disabled people and the elderly are activated, the demand of physical therapists will increase, especially for elderly people. Therefore, healthcare policy should focus on establishing rehabilitation service infrastructure suitable for an aging society, providing high-quality physical therapy services, and effective utilization of physical therapists.