• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.425-429
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• 2007

The noise problem has been a public interest for several years in Korea. Especially, the noises which were emitted from aircrafts on the airport and in the air have injurious effects on people over a vast range. Hence, there need vast data on the aircraft noise to evaluate the effect of various parameters. In present study, the works which consist of social surveys and noise measurements were conducted at points near the airport and the airbase. Total of 1,784 participants give effective responses in forty-five areas nearby the measurement points. Questionnaires asked the responses concerned with attitude, noise sensitivity, directive effects, secondary effects, annoyance and attempts to lower noise level exposed. From the field survey, the doseresponse relationship of community response to aircraft noise was established and there are different characteristics between civil and military aircraft. Though the study is still continuing on a few interest, one among some results is that %HA (%highly annoyed) of civil aircraft is higher than military's under the 70 WECPNL.

• International Journal of Ocean System Engineering
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• 제3권4호
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• pp.175-187
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• 2013

Moonpools are vertical wells in a floating body used onboard many types of vessels like Exploration and drilling vessels, Production barges, Cable-laying vessels, Rock dumping vessels, Research and offshore support vessels. Moonpool gives passage to underwater activities for different types of ships as per their mission requirements. It is observed that inside a moonpool considerable relative motions may occur, depending on shape, depth of the moonpool and on the frequency range of the waves to which the ship is exposed. The vessel responses are entirely different in zero and non-zero Froude number. Former situation is paid attention in this study as the mission requirement of the platform is to be in the particular location for long period of operation. It is well known that there are two modes of responses depending on the shape of the moonpool viz., piston mode for square shape and sloshing mode for rectangular shapes with different aspect ratios of opening like 1:1.5 and 1:2 ratios. Circular shaped moonpool is also tested for measuring the responses. The vessel moored using heavy lines are modelled and tested in the wave basin. The pretensions of the lines are varied by altering the touchdown points and the dynamic tensions on the lines are measured. The different modes of oscillations of water column are measured using wave gauge and the vessel response at a particular situation is determined. RAOs calculated for various situations provide better insight to the designer.

• ETRI Journal
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• 제39권2호
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• pp.151-162
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• 2017

With the remarkable growth in rich media in recent years, people are increasingly exposed to visual information from the environment. Visual information continues to play a vital role in rich media because people's real interests lie in dynamic information. This paper proposes a novel discrete dynamic swarm optimization (DDSO) algorithm for video object tracking using invariant features. The proposed approach is designed to track objects more robustly than other traditional algorithms in terms of illumination changes, background noise, and occlusions. DDSO is integrated with a matching procedure to eliminate inappropriate feature points geographically. The proposed novel fitness function can aid in excluding the influence of some noisy mismatched feature points. The test results showed that our approach can overcome changes in illumination, background noise, and occlusions more effectively than other traditional methods, including color-tracking and invariant feature-tracking methods.

• 한국수산과학회지
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• 제43권2호
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• pp.159-168
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• 2010

This paper presents a mathematical model and simulation method for investigating the performance of set net systems and fish cage systems influenced by currents and waves. Both systems consist of netting, mooring ropes, a floating collar and sinkers. The netting and ropes were considered flexible structures and the floating collar was considered an elastic structure. Both were modeled on a mass-spring model. The structures were divided into finite elements and mass points were placed at the mid-point of each element, and the mass points were connected by mass-less springs. Each mass point was subjected to external and internal forces and the total force was calculated at every integration step. An implicit integration scheme was used to solve the nonlinear dynamic system. The computation method was applied to dynamic simulation of actual systems simultaneously influenced by currents and waves in order to evaluate their practicality. The simulation results improved our understanding of the behavior of the structure and provided valuable information concerning the optimized design of set net and fish cage systems exposed to an open ocean environment.

• 한국치위생학회지
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• 제13권5호
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• pp.855-861
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• 2013

Objectives : This study aims to investigate the relationship between the self-leadership and stress of students majoring in dental hygiene in clinical practice. This study will be helpful to cope with clinical practice effectively. Methods : Subjects were 221 dental hygiene students from 4 universities in Daegu and Gyeongbuk. Data were abalyzed by independent t-test and multiple regression analysis. Results : Stress-response was 60.36 points in high self-leadership group and 57.20 points in kow self-leadership group. It was statistically significant. Clinical practice-induced stress was made by self-expectation, rehearsal, and self-criticism. Stress was able to be overcome by self-reward and positive mind. Conclusions : It is necessary to take the curriculum into consideration which can improve the self-leadership before the clinical practice or at the early phase of clinical practice in order to ensure that the students majoring in dental hygiene are exposed to less stress arising from clinical practice and better cope with such stress.

• 전력전자학회논문지
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• 제27권3호
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• pp.175-179
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• 2022

Magnetic arc extinguishing technology is effective as an extinguishing device for low-voltage direct current (DC) circuit breakers with a resistive load of ≤4 kW. The separation distance between the magnet and the electrical contact must be shortened to increase the magnetic arc extinguishing force. However, if the magnet is installed too close to the electrical contact points, the magnet is exposed to high temperatures due to the arc current generated when the load current is cut off and the magnetism is lost. To solve this problem, the effective magnetic flux density at the electrical contact can be maintained high by placing the arc extinguishing magnet in a tandem structure with the electrical contact point between them, and the proper separation distance between the contact points and the magnet can be maintained. In addition, an electric arc extinguishing technology that emits arc energy using a series circuit of diode and resistor is used to suppress the continuous arc voltage generated by the inductive load. For the proposed circuit breaker, the breaking characteristics are analyzed through the breaking test for the DC load of the 760 V level, the load power of 4 kW, and the time constant of 5 ms, and an appropriate arc extinguishing design guideline is proposed.

• Journal of Radiation Protection and Research
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• 제25권4호
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• pp.191-195
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• 2000

현재 서울대학교병원에서 진행중인 연구의 일환으로 혈관 내 방사선치료 시 시술자의 방사선피폭 정도 및 위험성에 대해 알아보고자 연구를 시행하였다. 심장혈관 폐색으로 연구에 포함되어 방사선치료른 시행 받은 42명의 환자 중 측정이 완벽한 34명의 자료를 토대로 분석을 시행하였다. 혈관내 방사선치료는 관상동맥성형술 직후 풍선도자법을 이용하여 대상 동맥의 중막에 17 Gy를 조사하였다. 사용된 동위원소는 $^{188}Re$이었으며 GM측정기로 각기 다른 8점에서 피폭선량을 측정하였다. 환자의 심장부위에서 10cm, 40cm 떨어진 지점을 시술자의 최대피폭량, 전신피폭량의 기준으로 삼았다. 치료선량의 중앙값은 111.6 mCi이었고 중앙치료시간은 576초였다. 환자 심장부위에서 l0cm, 40cm 지점의 평균 피폭 선량율은 0.43 mSv/hr, 0.30 mSv/hr 이었고, 각 지점에서의 시술 당 평균 피폭 선량은 0.07 mSv, 0.05 mSv 이었다. 이 수치는 ICRP-60나 과학기술부 고시에서 권고하고 있는 한계 피폭선량보다 훨씬 적은 값으로 현재 저울대학교병원에서 시행하고 있는 혈관내 방사선 치료법은 방사선방어 면에서 매우 안전한 방법임을 확인할 수 있었다.

• 농촌의학ㆍ지역보건
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• 제5권1호
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• pp.16-27
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• 1980

Five hundred seventeen farmers(214 males and 303 females), over age 30 and living in Suh San County, Unsan township, were examined to determine the prevalence of peasants syndrome. Using the health interview questionnaire, the farmers were asked whether they had any of eight subjective symptoms during the past one month before the survey, October 1979. Those symptoms reported were scored based on a pre-determined point system. The farmers with high symptom scores(7 points or more) were further examined by the liver function test. In addition, all the sample(517 cases) were subjected to the examination of urinalysis and blood pressure. The liver function test is also undertaken for those farmers with high symptome scores(7 points or more) and those with abnormal findings in urinalysis and blood pressure. The results are summarized below: 1) 156 out of 517 farmers(30.2%) have had seven points or more of the symptom scores. Among the eight major symptoms, 72% of the farmers complained of lumbago. 2) The prevalence of peasant's syndrome were higher among females and the older age group. The symptom scores of this syndrome were slightly higher among women who have had many children (e. g. 4 or more). 3) The prevalence of peasant's syndrome was also related to the level of one's education-the lower education groups were found to have higher symptom scores of this syndrome. This may be due to the fact that the lower education groups are more exposed to manual labor. 4) The points of the peasants syndrome were higher in hypertensive farmers and those with abnormal findings of urinaly sis. 5) It was reported, in Japan, that those with high scores of the syndrome are more likely to have an abnormal findings in the liver function test. However, in this study it was observed that there was no significant difference between those with high scores of the syndrome (7 points or more) and those with low score of the syndrome(6 points or less) in the prevalence of abnormal liver function. As this study indicates that the point system given for the peasant's syndrome is closely related to the high bleod pressure and abnormal urinalysis(and to some extent to the abnormal liver function), there is a need to study peasant's syndrome more extensively. Such an effort will serve to detect varonic disease conditions among farmer's towards better management of farmer's health, which is vitally important for rural development in Korea.

• 한국콘텐츠학회논문지
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• 제12권12호
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• pp.313-320
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• 2012

치과진료실은 다양한 종류의 병원성 미생물에 항상 노출되어 있으며, 환자의 분비물과 에어로졸 형태의 여러 경로를 통해 실내가 오염될 경우 교차감염의 매개 장소가 될 수 있다. 교차감염의 위험이 산재되어 있는 치과진료와 치과진료실에서 교차감염 방지의 주체자는 치과위생사이다. 치과위생사는 임상 전문가로 활동하기 전에 감염방지에 대한 올바른 인식을 가지고 있어야 되며, 이러한 감염방지 인식수준은 임상실습에서부터 영향을 받는다. 이에 감염방지의 인식을 조사하고자 일부 4년제 대학교 치위생학과 교육과정 중 3학년 과정에 임상실습이 정규과목으로 정해져있는 학생 314명을 대상으로 자기기입식 설문조사를 실시하였다. 자료 수집은 2011년 12월 9일부터 2012년 2월 22일까지 수행하였고, 수집된 자료 중 응답이 불성실한 11부의 설문지를 제외한 303부를 SPSS WIN 20.0을 사용하여 최종 분석하였고, 다음과 같은 결론을 얻었다. 감염질환에 관한 인식 영역에서 교내 외 실습 경험군은 감염질환 인지의 중요성 문항에서 4.89점, B형간염 예방접종 의무의 문항에서는 4.65점, B형간염 예방접종 필요성 인식의 문항에서는 4.77점, 문진 실시하여 감염방지를 실천할 수 있는지에 대한 문항에서는 4.71점, 감염방지 교육의 도움에 관한 문항에서는 4.76점으로 가장 높았으며, 유의한 차이를 보였다. 치위생학과 학생들을 위한 체계적이고 다양한 감염방지 교육 프로그램 개발과 학년에 따른 차별적인 교육이 필요하다고 사료된다.

• 한국환경생태학회지
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• 제26권5호
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• pp.827-834
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• 2012

본 연구는 백두대간권역의 설악산, 속리산국립공원 비개방 탐방로를 대상으로 탐방로 특성과 이용에 따른 영향을 파악하여 핵심지역 보전을 위한 공원관리와 비개방에 따른 이해 당사자들간의 갈등 해결을 위한 정책반영 기초자료 제시를 목적으로 하였다. 설악산국립공원 비개방 탐방로 3개 구간, 속리산국립공원 비개방 탐방로 1개 구간 총 17.1km, 112개 조사지점의 탐방로 특성을 조사한 결과 평균 노폭은 0.98m, 평균 나지폭은 0.84m, 평균 최대침식깊이와 종단경사는 각각 11.6cm, 14.2%이었다. 훼손유형 발생빈도는 뿌리노출이 53개소(47.3%)로 가장 많았으며 훼손영향이 적은 건전지점은 47지점(42.0%)이었다. 본 조사대상지는 산악형 국립공원의 개방 탐방로에 비해 훼손 압력은 적으나 국립공원을 일부 포함하는 다른 지역의 백두대간 마루금 탐방로와 비슷한 압력을 받고 있었다.