• Geomechanics and Engineering
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• 제16권3호
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• pp.285-293
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• 2018

In densely populated urban areas with a large amount of infrastructure, ground subsidence events can result in massive casualties and economic losses. In South Korea, the incidence of ground subsidence in urban areas has increased in recent years and the number of underground cavities suspected of causing such events has significantly increased. Therefore, it is essential to develop techniques to prevent the occurrence of underground and ground subsidence. In this study, a field test, laboratory test, and numerical analysis were conducted to determine the optimal compaction degree of the upper support layer of any underground cavity below the level of sewer pipes in order to prevent such cavities from collapsing and leading to ground subsidence accidents. During the field test, an underground cavity was simulated using ice, and the generation of the cavity was confirmed using ground penetrating radar. The ground investigation was performed using a cone penetration test, and the compaction of the ground where ground subsidence occurred was evaluated with a laboratory test. The behaviour of the ground under various conditions was predicted using a numerical analysis based on the data obtained from the field test and previous studies. Based on these results, the optimal compaction degree of the ground required to prevent the underground cavity from causing ground subsidence was predicted and presented.

• Nutritional Sciences
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• 제5권2호
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• pp.103-110
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• 2002

In Korea, the school foodservice program has been expanding rapidly in recent years, partly as a result of increased government support. With the growth in the number of schools offering foodservice programs, food safety and sanitation concerns have been increasing. To assist with program improvement, a situation analysis was carried out, with the focus on equipment and sanitary management of school foodservice programs under flour different management systems. A questionnaire was mailed to the foodservice directors of 234 randomly selected schools chi[h included elementary, middle and high schools at the national level. Among them, one hundred and sixty-five responses reasonably completed were used for the analysis. This study classified each school's foodservice management into one of four types : independent-conventional, independent-commissary, contract-conventional, and contract-delivery. The results show that the monitoring of employees' health and personal hygiene, and employees' sanitary education was well conducted, but that the sanitary education of the voluntary parent workers was largely ignored. Eighty-six percent of the schools had their drinking water tested for sanitation, and the results showed that more effort is needed in careful management of drinking water in order to prevent foodborne illnesses and bacillary dysentery. In general, contract management showed lower scores in foodservice equipment and their efficiency, compared with independent management. A relatively high number of schools on the contract-delivery management system employed nurses and leachers instead of dietitians and foodservice directors. The adoption of the HACCP (Hazard Analysis Critical Control Point) system was lowest in contract-conventional and contract-delivery management systems, and highest in elementary schools using the independent-conventional system.

• Toxicological Research
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• 제31권1호
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• pp.69-75
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• 2015

The objective of this study was to investigate the toxicological information of freeze-dried powder from Allomyrina dichotoma (A. dichotoma) larvae as a food ingredient. The powder, suspended in distilled water, was administered once daily by oral gavage to four groups of Sprague-Dawley (SD) rats at dose levels of 0 (vehicle control), 250, 850, and 2500 mg/kg/day. After 13 wks of repeated administration, the standard toxicological parameters such as mortality, clinical signs, body weight, food consumption, ophthalmologic examination, clinical pathology, organ weights and macro/microscopic examination were applied for assessment of general toxicity. In addition, serum IgE and histamine levels were determined to evaluate allergenicity. The freeze-dried powder from A. dichotoma larvae did not produce treatment-related changes or findings in any toxicological parameters in either sex of any dosed groups except for slight increases in serum histamine levels at 2500 mg/kg/day. The changes were considered not to be adverse since the magnitude was minimal. In conclusion, the NOAEL (No Observed Adverse Effect Level) of the freeze-dried powder from A. dichotoma larvae was determined to be 2500 mg/kg/day or more in both sexes of SD rats and it is considered a candidate to be edible material.

• 한국식품영양학회지
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• 제25권2호
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• pp.215-223
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• 2012

The principal objective of this study was to evaluate the consumption behavior of housewives in the Jeonju area with respect to their use of environmentally-friendly agricultural products(EAPs) and to assess the need for EAPs in childcare centers also in the Jeonju area. Self-administered questionnaires were given to and collected from 278 housewives 42.4% of whom employed and 57.6% were unemployed. Statistical data analysis was performed on the data collected using SPSS v. 12.0. The average score of awareness about EAPs was $3.57{\pm}0.56$. The percentage of subjects who purchased EAPS was 76.3% regularly. On this group, 40.3% purchased EAPs 1~2 times in week. Unemployed housewives purchased more than employed housewives by a statistically significant margin(p<0.05). The most-purchased EAPs were vegetables. The average satisfaction score that housewives reported in relation to foodservice provided in childcare centers was $3.66{\pm}0.58$. About 65% of the respondents felt that the EAPs-foodservice in childcare centers was an important factor for them in choosing of a childcare centers. Approximately 42% of the housewives responded that EAPs-foodservice in childcare centers was needed to improve the safety of foodservice provided in chidcare centers. The percentage of subjects who wanted to expand EAPs-foodservice in childcare centers even though the parents would have to bear some of the financial burden was 42.5%. A higher proportion of employed housewives wanted to expand EAPs-foodservice in childcare centers more than unemployed housewives, and this finding was statistically significant(p<0.05).

• Structural Engineering and Mechanics
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• 제31권5호
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• pp.507-526
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• 2009

Based on numerical and experimental methods, a systematic structural evaluation of a steel natatorium in service was carried out in detail in this paper. Planning of inspection tasks was proposed firstly according to some national codes in China in order to obtain the economic and reliable results. The field visual inspections and static computation were conducted in turn under in-service environmental conditions. Further a three-dimensional finite element model was developed according to its factual geometry properties obtained from the field inspection. An analytical modal analysis was performed to provide the analytical modal properties. The field vibration tests on the natatorium were conducted and then two different system identification methods were used to obtain the dynamic characteristics of the natatorium. A good correlation was achieved in results obtained from the two system identification methods and the finite element method (FEM). The numerical and experimental results demonstrated that the main structure of the natatorium in its present status is safe and it still satisfies the demand of the national codes in China. But the roof system such as purlines and skeletons must be removed and rebuilt completely. Moreover the system identification results showed that field vibration test is sufficient to identify the reliable dynamic properties of the natatorium. The constructive suggestion on structural evaluation of the natatorium is that periodic assessment work must be maintained to ensure the natatorium's safety in the future.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 공동학술발표회
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• pp.82-82
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• 2017

우리나라로 회귀하는 연어는 북태평양에서 서식하는 연어 중 가장 넓은 영역에 분포하고 있으며, 경제적으로 매우 중요한 어류로서 이들의 자원관리를 위한 유전학적 연구가 활발히 진행되고 있다. 특히, 베링해와 북태평양 지역은 연어의 주 성장지로서 인접국가에서 산란된 연어들이 혼재되어 있어 국가별 연어의 계군을 구분할 수 있는 유전적 마커 개발 및 적용이 필요하고. 본 연구에서는 각 국가별 연어 집단에 대한 유전적 다양성, 차이점, 구조 및 인구통계학적 연구를 통한 유전학적 특징을 밝히고, 베링해와 북태평양 지역에서 성장하고 있는 연어의 국가별 계군의 분포와 이동 양상을 제시하려 한다.

• 한국입자에어로졸학회지
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• 제10권4호
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• pp.137-154
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• 2014

문헌조사를 통해 그동안 선행연구로부터 밝혀진 방사성 에어로졸의 특성을 종합하고 정리하였다. 가상사고 실험 중 각재계통 및 원자로건물에서 측정한 에어로졸의 특성, 냉각재계통 및 원자로건물에서의 방사성 에어로졸 거동 해석을 위해 사용된 모델 에어로졸의 특성, 공학적 안전설비 성능평가를 위한 실험에 사용된 모델 에어로졸의 특성 등과 관련한 선행연구 내용을 종합해 볼 때, 원전사고 시 발생하는 에어로졸의 MMD는 $0.1{\sim}5{\mu}m$, GSD는 1.33~2.9, 에어로졸 농도는 $0.06{\sim}132g/m^3$의 범위를 보였다. 향후 공학적 안전설비의 설계를 위한 MMD와 GSD의 대표값은 대략 $1.5{\mu}m$와 1.8 내외라고 할 수 있으며, 에어로졸 농도는 대략 $10g/m^3$을 대표값으로 볼 수 있다.

• 한국가스학회지
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• 제4권3호
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• pp.53-58
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• 2000

CNG 충전소에 대한 사고영향평가(CA) 분석을 실시하였고 이미 고압법에 의해 설치되어 있는 LPG 충전소에 대한 CA를 실시하여 서로 비교하였다. CNG 충전소와 LPG 충전소에 대한 누출 확산 및 복사열의 영향평가 결과 연소하한계에 도달하는 거리는 CNG 충전소가 LPG 충전소에 비해 약 1.5배 컸으며, 복사열의 경우 공정장치에 손상을 줄 수 있는 복사열량이 CNG 충전소에서는 나타나지 않았으나 LPG 충전소의 경우 37.5 $kw/m^2$에 해당하는 복사열이 12.6 m 반경으로 나타나 주변의 상가지역까지 큰 영향을 미칠 수 있는 것으로 나타났다. 또한, 목재를 태울 수 있을 정도의 복사열량인 12.5 $kw/m^2$은 LPG 충전소가 CNG 충전소에 비해 약 3배 가량 큰 것으로 나타났다.

• 한국재난정보학회 논문집
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• 제9권3호
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• pp.266-275
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• 2013

최근 복합재난 환경 속에서 지역 방재력을 구축하기 위한 재난안전관리의 선진화에 대한 새로운 패러다임이 요구되어지고 있다. 이러한 상황속에서 2012년 9월 구미 불산 유출사고를 겪으면서 지방자치단체의 재난안전 역량의 중요성 및 필요성이 부각되었다. 이와 함께 안전 확보에 대한 국민의 관심도 증대는 지역 주민들의 재난안전정보에 대한 권리를 가시화하였고 사회적 이슈로 나타났다. 본 연구에서는 지방자치단체의 재난관리 업무역량을 평가 분석 할 수 있는 프로그램을 개발하였다. 재난관리 역량강화 지표를 데이터베이스화하여 재난관리담당자 중심의 웹 기반 체계를 구축하여 지방자치단체가 자체적으로 재난안전관리 역량 수준을 파악하도록 하였다. 또한, 재난안전관리 정보를 지역주민들이 이해하기 용이하게 지표화하여 공개하도록 하였다. 지방자치단체의 재난관리 역량강화를 위해서는 지역의 취약성을 분석하여 개선사항을 도출하는 노력과 함께 이를 지역주민에게 공시함으로서 지역사회의 참여를 바탕으로 최적의 효과를 거둘 수 있을 것이라 기대한다.

• 한국지진공학회논문집
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• 제23권6호
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• pp.311-319
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• 2019

The number of aged bridges is increasing so that bridges over 30 years old account for about 11% of all bridges. Consequently, the development of a seismic performance evaluation method that considers the effects of ageing is essential for a seismic retrofitting process for improvement of the seismic safety of existing old bridges. Assessment of the damage situation of bridges after the recent earthquakes in Korea has been limited to the bearings, anchor, and concrete mortar on piers. The purpose of this study is to evaluate the seismic responses of PSC box girder bridges by considering the ageing effect of rubber bearings (RBs) and lead-rubber bearings (LRBs). The modification factor proposed by AASHTO is used to take into account the ageing effect in the bearings. PSC box girder bridges with RBs and LRBs were 3D modeled and analyzed with the OpenSEES program. In order to evaluate the ageing effect of RBs and LRBs, 40 near fault and 40 far field records were used as the input earthquakes. When considering the effect of ageing, the displacement responses and shear forces of bridge bearings (RBs and LRBs) were found to increase mostly under the analytical conditions. It was shown that the effect of ageing is greater in the case of RBs than in the case of LRBs.