• Journal of dental hygiene science
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• v.13 no.4
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• pp.501-509
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• 2013

The purpose of the study is to confirm the effect of the oral health management program in exemplary kindergartens for prevent the dental caries. The study performs the survey on the parents about the changes in the oral health behaviors after the oral health education in April 2012 and measures the patient hygiene performance (PHP) index before the education, after the education and 3 weeks after the education to assess the removal capability to plaque on the teeth surface for the children. The analysis is performed on 130 people who join the program and respond the survey. There is no change in the behavior related to the tooth brushing of children after the oral health education. No change is found from the interest in the oral health education (p>0.05) but the recognition in the importance of the tooth positively change, as well as recognition of the tooth brushing method and the reaction to recommending to tooth brushing. The PHP index of children is significantly improved from 3.87 before the education through 2.71 after the education and 3.27 3 weeks after the education (p<0.001). The observation from the patents shows that their children have interest in preventing the cavities including 33.1% after having xylitol and 60.7% after the oral health education. In conclusion, the study confirms the effect of the oral health management program in exemplary kindergartens to prevent the cavities, meaning that it is required to activate the programs and keep implementing the programs including providing xylitol and education for teachers, parents and children to habituate the oral health behavior of the children and completely learn toothbrushing method under continuous management and reeducation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.619-634
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• 2015

The objective of this study was to provide information on difficulties in performing tasks of employees of the Center for Children's Foodservice Management (CCFSM) to obtain information as a resource for improving work performance. Data were collected from employees working at the CCFSM over a period of 6 months until December 2013. The recruitment period was from 16 December, 2013 to 30 January, 2014. A total of 228 employees (79.7%) participated in the study, and 227 completed questionnaires were analyzed. Statistical analyses were performed on data utilizing the SPSS V20.0. Employees tasked with 'nutrition guidance visits', 'hygiene safety guidance visits', and 'teaching to cook visits' who worked outside of the office frequently had difficulties with 'physical exhaustion'. They reported that 'working outside of the office encumbers later office work' and that 'employees' suggestions for changes are not easily accepted in child-care facilities. The following statements in the questionnaire were highly rated by each of the employees in charge of 'Gathering training' and 'Budget management': 'As a gathering training is conducted within the working hours of child-care facilities, participation rate is low' and 'The differences in regulations of consignment organization, local government, and KFDA are confusing'. This study also suggests that CCFSMs should have authority over child-care facilities, which demonstrate no desire for improvement even after CCFSM employees offer several suggestions for better foodservice or deliberately avoid participating in CCFSMs without good reasons. Besides, CCFSMs are supported by the KFDA and can lessen the workload of child-care facilities in developing educational materials for better foodservice.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.572-581
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• 2023

Purpose: The purpose of this study is to improve the irregularity of the stress-strain curve and to ensure accuracy when calculating the damping effect by preventing members from moving in the off-plane direction due to eccentricity when loads are applied. Method: The specifications of the steel strips used in this study are the same, but the curvature of the strips to constitute each damper is different. Each steel strip with different curvature was arranged in an triangle, three dampers with different curvature were made, and repeated load tests were conducted, and the amount of energy dissipation was calculated to measure the performance of the damper. Result: The amount of energy dissipation significantly decreases compared to the case where there is no initial curvature, and the change in the test energy dissipation amount according to the size of the curvature is not large, and the presence or absence of the hyperbolic rate is considered an important variable. Conclusion: The period is about 78.7% longer from T=0.3 to T=0.536sec, and the response spectrum acceleration is reduced from Sa=0.54g to Sa=0.229g, so the damping effect of the damper is sufficient.

• Progress in Medical Physics
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• v.11 no.1
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• pp.19-27
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• 2000

In order to predict the propagation of road traffic noise over level terrain, this paper presents the model of the simple monopole and dipole source. Excess attenuations by ground acoustic impedance with continuity are investigated by outdoor experiments. In this results, the propagation of road traffic noise is affected by the acoustic impedance properties of the ground surface over which the noise travels, particularly when the receiver position is close to the surface. These results are then used to derive sound pressure level contours for the attenuation with distance of the equivalent energy level received from passing vehicle. The percentage of deep sleep and the number of wakings are studied for continuous traffic noise. The hearing loss and sensitivity threshold shift is investigated by changing the various parameters such as the effects of aging and noise exposure. Evaluation of the response of human to traffic noise is discribed. It is shown that exposure to excessive noise can cause temporary loss of hearing that may become permanent if the exposure is prolonged or intense.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.9-16
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• 1997

Ferroelectric $Pb_5Ge_{3-x}Ti_xO_{11}$(x=0, 0.015, 0.021, 0.03) single crystals were obtained from the melt by the Czochralski method. Grown crystals were pale brownish yellow and fully transparent. The dielectric relaxation of the $Pb_5Ge_{3-x}Ti_xO_{11}$ single crystals has been studied in the frequency range from 100 Hz to 10 MHz between $20^{\circ}C$ and $600^{\circ}C$. From the results of the these measurements. the temperature of the permittivity maximum was shifted to low temperature with increasing Ti content and the permittivity maximum decreased with increasing Ti content. The frequency dependent dielectric response of $Pb_5Ge_{3-x}Ti_xO_{11}$ single crystals exhibits a Debye type relaxation, with a distribution of relaxation times. Dielectric behavior is characteristic of carrier-dominated response.

• Korea lubricating oil industries association bulletin
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• no.18
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• pp.12-22
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• 1986

국내정유산업의 후방부문인 윤활유사업은 산업의 발전과 함께 국내 진출, 다국적석유기업에 의하여 원료 및 첨가제의 공급에 의한 단순생산과 마아케팅을 하여 국내시장을 지배하여 왔다. 또한 중화학공업의 발달과 함께 산업기계에 요구되는 윤활유제품도 다양화와 품질고급화로 시장구조가 점점 변화되고 있다. 국내윤활유총생산량중 65$\%$의 시장을 가지고 있는 고급윤활유시장은 4개 제조회사에 의하여 96$\%$의 시장을 유지하고 있다. 각 제조회사의 시장확대정책에 의하여 각대리점에 대한 유통경로의 관리가 중요 마아케팅전략음 되고 있는 실정이다. 제조회사의 대형 소비자에 대한 직매, 직영대리점, 일반대리점에 대한 유통기구중 많은 판매비중을 차지하고 있는 일반대리점에 대하여 4P를 기준하여 대리점측 입장에서 마아케팅 믹스를 분석하였다. 제조회사가 판매대리점에 취하는 마아케팅 전략중 직접적인 방법과 간접적인 방법이 시장관리에 나타나는 갈등정도를 가설로 설문지를 작성하여 6월 10일부터 6월 19일까지 경인지역은 조사원에 의한 직접방문과 지방은 등기우편에 의하여 50개 일반대리점에 송부하여 60$\%$의 회수율을 보였다. 응답자료를 통하여 제조회사의 직접적인 시장관리방법과 간접적인 시장관리방법을 사용시 일반대리점에 대한 갈등해소 정도를 상관분석을 통한 통계처리를 하였다. 본 연구결과는 다음과 같은 사실을 얻을수 있었다. 제조회사가 일반대리점에 실시하는 직접적 또는 간접적인 시장관리는 일반대리점에 대하여 갈등해소에 커다란 작용을 하지 못한다. 따라서 제조회사는 유통경로에 대한 전략을 첫째, 일반대리점과 직영대리점과의 시장에 대한 마찰해소 둘때, 대리점에 대한 안정적인 판매이윤제공 셋째, 계획적인 판매대리점간 시장경쟁조정 넷째, R & D 투자강화로 제조회사 차원에서 공동으로 산학협동하여 첨가제 및 상표의 국내개발을 이루어 제품가격인하로 장기적인 시장개발이 요청된다는 결론을 얻었다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.1
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• pp.37-46
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• 2003

The transient responses on arbitrarily interconnected digital transmission lines are analyzed by an efficient node discretization technique. Since the proposed node discretization technique offers an efficient means to discretize transmission lines, the transient waveform at any position on the arbitrarily interconnected lines is easily predicted. Dispersive microstrip multiconductor transmission lines arbitrarily connected are analized for generality. The derivation of frequency-dependent equivalent circuit elements of coupled transmission lines have been carried out by the spectral domain approach(SDA). The effects of variations of excited pulse width on the crosstalks of the high-speed microstrip coupled-lines are also investigated. It has been well known that the crosstalk spike level is monotonously increased when the coupling length and effective permittivity of substrate are increased. In this paper, it is found that the variations of crosstalk level are not further monotonous as shortening the exciting pulse width toward several picosecond. The results are verified by the generalized S-parameter technique.

• Journal of IKEEE
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• v.26 no.2
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• pp.287-291
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• 2022

In general, as the amplitude and phase information of the physical layer channel impulse response change rapidly in time and frequency according to the high-speed movement of the vehicles in V2X communication systems, it is difficult to accurately estimate these channels at the receiving end. In order to effectively overcome this problem, midamble-based channel estimation methods in which mid-ambles are periodically inserted into a packet have been recently considered. However, as the number of midambles increases, we suffer from the spectral efficiency loss. To relieve such a loss, in this paper, we propose a new bidirectional averaging channel estimation method that combines the existing data pilot-based channel estimation methods and the mid-ambles. Finally, through the simulation results, we demonstrate that the proposed method outperforms the existing mid-amble method in terms of packet error rate with fewer number of mid-ambles.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.245-253
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• 2021

RC slab bridges account for the largest portion of deteriorated bridges in Korea. However, most RC slabs are not included in the first and second classes of bridges, which are subject to bridge safety management and maintenance. The highest damaged components in highway bridges are the subsidiary facilities including expansion joints and bearings. In particular, leakage through expansion joints causes deterioration and cracks of concrete and exposure of reinforced bars. Therefore, this study analyzed the effect of adhesion damage at expansion joints on the response of the deck in RC slab bridges. When the spacing between the expansion joints at both ends was closely adhered, cracks occurred in the concrete at both ends of the deck due to the resistance rigidity at the expansion joints. Based on the response results, the correlation analysis between displacements in the longitudinal direction of the expansion joint and concrete stress at both ends of the deck for each damage scenario was performed to investigate the effect of the occurrence of damage on the bridge behavior. When expansion joint devices at both sides were damaged, the correlation between displacement and stress showed a low correlation of 0.18 when the vehicles proceeded along all the lanes. Compared with those in the intact state, the deflections of the deck in the damaged case at both sides showed a low correlation of 0.34 to 0.53 while the vehicle passed and 0.17 to 0.43 after the vehicle passed. This means that the occurrence of cracks in the ends of concrete changed the behavior of the deck. Therefore, data-deriven damage detection could be developed to manage the damage to expansion joints that cause damage and deterioration of the deck.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.12a
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• pp.139-143
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• 2004

최근 고 해상도 위성영상정보의 민간 활용에 대한 수요가 증가하면서 기존의 공간 정보를 다루는 여러 응용분야에서 이에 관련된 많은 연구를 하고 있다. 도시교통 환경 분석을 위하여 위성영상정보를 처리하는 과정에 있어서 도로, 건물, 기타 선 구조와 같은 지형지물을 분석하는 과정은 사용자에 따라 주관적일 수 있다. 이러한 배경에서 수학적 그레이 레벨 모폴로지는 하나의 효과적인 접근으로 간주된다. 본 연구에서 지형지물 추출을 위해 윈도우 운영체제에서 실행되는 실질적인 응용 프로그램을 구현하였다. 이 프로그램에서 주요한 지형지물은 그레이 레벨 영상을 이용하여 개방(opening), 폐쇄(closing), 침식(erosion), 팽창(dilation)의 순차적 처리를 통하여 자동적으로 추출된다. 결과적으로, GDPA, 허프 변환 또는 다른 알고리듬들과 비교시 하나의 이점이 된다. 모폴로지 처리와 같이 본 프로그램은 그레이 레벨 값의 범위에 기반하여 지형지물을 추출을 위한 density slicing 기능 또는 주어진 경계치 보다 작은 화소 군집을 제거하는 처리인 'sieve filtering'을 제공한다. 이러한 기능들은 형태학적으로 처리된 결과를 증대하고 지형지물 종류들을 분리하는데 유용하다. 또한 배경의 제거, 잡음 탐지, 도시 환경 원격 탐사에서의 지형지물 특성화에 기여한다. 본 프로그램을 이용하는데 있어서 IKONOS 위성영상을 이용하여 시험 구현하였다. 결과, 다중 경계치 또는 steve filtering을 이용한 그레이 레벨 모폴로지 처리는 복잡한 지형지물과 많은 데이터로 구성된 고해상도 영상 내의 주어진 대상에서 자동적인 처리와 사용자 정의 sieve filtering으로 인한 효과적인 지형지물 추출 방법으로 간주 된다. 시안을 작성 표준화를 위한 첫 단계 시도를 소개하였다.분석 결과는 문장, 그림 및 도표, 장 끝의 질문, 학생의 학습 활동 수 등이 $0.4{\sim}1.5$ 사이의 값으로 학생 참여를 적절히 유도하는 발견 지향적 인 것으로 조사되었다. 그러나 장의 요약은 본문 내용을 반복하는 내용으로 구성되었다. 이와 같이 공통과학 과목은 새로운 현대 사회에 부응하는 교과 목표와 체계를 지향하고 있지만 아직도 통합과학으로서의 내용과 체계를 완전히 갖추고 있지 못할 뿐만 아니라 현재 사용되고 있는 7종의 교과서가 교육 목표를 충분히 반영하지 못하고 있다. 따라서 교사의 역할이 더욱더 중요하게 되었다.괴리가 작아진다. 이 결과에 따르면 위탁증거금의 징수는 그 제도의 취지에 부합되고 있다. 다만 제도운용상의 이유이거나 혹은 우리나라 주식시장의 투자자들이 비합리적인 투자형태를 보임에 따라 그 정책적 효과는 때로 역기능적인 결과로 초래하였다. 그럼에도 불구하고 이 연구결과를 통하여 최소한 주식시장(株式市場)에서 위탁증거금제도는 그 제도적 의의가 여전히 있다는 사실이 확인되었다. 또한 우리나라 주식시장에서 통상 과열투기 행위가 빈번히 일어나 주식시장을 교란시킴으로써 건전한 투자풍토조성에 저해된다는 저간의 우려가 매우 커왔으나 표본 기간동안에 대하여 실증분석을 한 결과 주식시장 전체적으로 볼 때 주가변동율(株價變動率), 특히 초과주가변동율(超過株價變動率)에 미치는 영향이 그다지 심각한 정도는 아니었으며 오히려 우리나라의 주식시장은 미국시장에 비해 주가가 비교적 안정적인 수준을 유지해 왔다고 볼 수 있다.36.4%)와 외식을 선호(29.1%)${\lrcorner}$ 하기 때문에 패스트푸드를 이용하게 된 것으로 응답 하였으며,