• 한국정밀공학회지
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• 제28권6호
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• pp.709-715
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• 2011

Chattering in cutting operations are usually a cumbersome part of the manufacturing process in mechanical. Particular, machining performance such as that of the boring process is limited by cutting condition at the movable components. Among various sources of chatter vibration, detrimental point in cutting condition is found a mechanical condition on overhang. It limits cutting speed, depth, surface roughness and tool wear failure as result because the all properties are varying with the metal removal process. In this case, we have to observe the resonance frequencies of a boring bar for continuous cutting. In the established research, boring bar vibration of cutting system has been measured with the aid of accelerometer. However, the inherent parameters of internal turning operations are severely limit for the real time monitoring on accelerometers. At this point, this paper is proposed other method for real time monitoring during continuous cutting with optical fiber at the inside of boring bar. This method has been used a plastic fiber in the special jig on boring bar by based on experimental modal analysis. In this study, improvement of monitoring system on continuous internal cutting was attempted using optical fiber sensor of inside type because usually chattering is investigated experimentally measuring the variation in chip thickness. It is demonstrated that the optical fiber sensor is possibility to measure of chattering with real time in boring process.

• 한국철도학회논문집
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• 제14권3호
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• pp.234-239
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• 2011

선로하부를 굴착한 후의 가설교량 설치공법은 이동형 가로보를 갖는 공법으로 시공시 전차선 차단 및 레일절단이 불필요하고 열차운행 횟수가 많은 복선부에서도 적용 가능한 공법이다. 본 논문에서는 공사구간이 곡선부(R400)구간으로 가설교량 공법 시공 후의 변위특성을 검토하기 위해 변위계를 설치하고 열차 통과 시의 윤중 횡압을 계측하여 곡선부(R400)의 주행안전성 검토를 평가하였다. 측정결과 가설교량을 통과시 열차종별 윤중과 횡압의 최대값은 각각 국외 궤도성능평가 기준의 51%, 81% 수준으로 분석되어 윤중, 횡압 발생에 따른 궤도 안전성 측면에서는 큰 문제가 없을 것으로 판단된다. 또한 주행안전성의 평가기준이 되는 최대 탈선계수와 최대 윤중감소율은 열차종별에 관계없이 허용한계치의 49% 수준으로 그 기준치에는 못 미치는 것으로 나타나 열차 통과시의 주행안전성 확보에는 큰 문제가 없는 것을 알 수 있었다.

• 대한두경부종양학회지
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• 제18권1호
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• pp.65-70
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• 2002

Background and Objectives: Recently the tenn 'papillary microcarcinoma' has been proposed to designate carcinoma of 10 mm or less in diameter. In some cases, cervical lymph node metastasis preceding the occurrence of the primary tumor may be the first and sole manifestation of the disease. The objective of this study is to assess the clinical features of cervical metastasis in papillary microcarcinoma of thyroid glands. Materials and Methods: 9 cases with papillary microcarcinoma with neck metastasis were analyzed retrospectively. 5 cases are men and 4 are women. All patients complained of painless, movable neck mass. The symptom had been present from 1 month to 36 months. We reviewed clinical history, imaging studies, the results of fine needle aspiration, the surgical method, the pathologic results. Results: In 9 cases, no abnormalities of the thyroid gland were shown by imaging studies and thyroid scan. 3 cases were diagnosed by fine needle aspiration cytology. the others were not. Total thyroidectomy and neck dissection were performed in 9 cases and then pathology reports showed 2 case of multiple, 2 case of contralateral single and 5 cases of unilateral single thyroid microcarcinoma. They have no recurrence during follow-up period. Conclusions: Cervical metastasis from papillary microcarcinoma is variable clinical manifestation. The diagnosis of cervical metastasis from papillary microcarcinoma should be considered in patient with neck mass. We recommend total thyroidectomy with neck dissection and postoperative radioactive iodine ablation therapy in neck metastasis from papillary thyroid microcarcinoma.

• 한국환경복원기술학회지
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• 제17권6호
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• pp.1-15
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• 2014

A dredging on erosion control dam has been enforced without evaluation the factors that affect the dredging. In addition, there is the negative effect much more than positive effect by dredging on erosion control dam. Therefore, this study was carried out to develop evaluation indicators and to suggest fieldbook in order to determine whether sand deposits at erosion control dam should be dredged up or not. The most important six evaluation indicators that can decide to dredge up at erosion control dam were obtained from three round delphi technique and were selected in the following order: the current sand deposit ratio(0.339), existence of cultivated land and house downstream(0.276), the slope of streambed(0.162), the amount of movable soil and gravel(0.118), the history of any disasters(0.063), the basin area(0.043). The weighted score for each evaluation indicator were acquired from AHP analysis with respect to the degree of importance and then the modified weighted score for actual measurements were classified as three categories: large(2.53), medium(1.60) and small(1.01). Based on delphi technique, erosion control dam dredging evaluation fieldbook introduced the four evaluation indicators out of the total six evaluation indicators and two low effected evaluation indicators were excluded. This results showed that the values for reliability analysis and consistency ratio were acceptable.

• 한국학교보건학회지
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• 제3권1호
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• pp.73-82
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• 1990

Sex does not mean simply the physical behaviors related to man and woman, rather the sexuality needed socializing process toward total personality. It is believed that religion or social norms on sex, limit talking about sex openly. But children have, their own sexual thinking and want to know why and how. This survey was conducted to find out the need in sex education of primary school students and their parents in Seoul area, comparing students'sexual knowledge, attitude, and behavior to their parents', in October 1989. Total 400 students and their parents who are attending two primary school in Seoul, were given the questionnaires, and 395 students' and 310 parents', respectively, were finally analyzed. The following results were obtained. 1. The mean of 11 questions In asking sexual knowledge of students was 6.18, and showed no difference between boys and girls. But the higher grade, the higher score. 2. The positive attitudes on marriage and sex roles were showed, but negative on physical changes with puberty, which was same to the parents' reaction. 3. Moro than three-forths of students wanted to take sex education class, and one-third of them believed that it should be conducted by school nurses. This was accorded with their parents. 4. The sexual knowledge degree and attitudes of parents went proportionately to their higher educational background. Protestants reacted more negatively to the given sexual terms. No significant difference was made among the age groups of them. As stated above. the degree of sexual knowledge and attitudes are movable accordingly to their children's sexual thinking and need. Therefore, it is strongly recommended that sex education In the primary schools should be conducted systematically involving parents, especially mothers. And it is suggested that school nurses undertake their responsibilities as the sex educators.

• 전기학회논문지P
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• 제67권3호
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• pp.168-174
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• 2018

The performance test for 376MW ESS for frequency regulation currently operating in 13 substations is conducted based on the test procedure in the first and second steps. In the first step, components of ESS is moved to the certification authority where the test equipment is located in order to be proceeded with the test. In the second step, the performance test is conducted manually for the ESS equipments installed on site using the movable measurement equipment, and thus it can only be performed on some limited test items and requires a lot of time and manpower. Therefore, mobile test equipment for ESS(MOTES) is being developed that can perform automatically more test items for ESS in the field using the MOTES, and reduce manpower and time. To do this, an algorithm and a prototype of the operating system(MOS) are also being developed that can control MOTES automatically. In this paper, a development of the MOS prototype is introduced and then a simulation is performed to verify the prototype and its algorithm before the field demonstration.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 추계 학술대회논문집
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• pp.127-138
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• 1999

본 연구에서는 2 차원 캐비티 유동에서 경계조건 부여 방법의 차이에 따른 유체유동의 이력이 최종적인 정상상태에 미치는 효과를 수치실험을 통하여 관찰하였다. 그 결과 유동의 Reynolds 수가 작은 경우는 유동장이 가지는 이력이 시간의 경과와 함께 소멸하여 하나의 정상유동 상태를 가지는데 반하여, 큰 Reynolds 수에서는 유동장 이력이 소멸하지 않고 유지됨으로 인하여 다수의 정상유동 형태가 나타남이 확인이 되었다. 엄밀한 이론적 해석은 현재 이루워지지 않았으나 유체 운동량의 증가에 따라 Navier-Stokes 방정식의 비선형성이 영향을 미치고 있다고 여겨진다.

• 복식
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• 제62권7호
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• pp.133-149
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• 2012

Jikji, Memory of the World of UNESCO, the world's oldest extant movable metal print book, is a cultural heritage to give motivation for IT power of Korea. Although the cultural value of Jikji is understood in Korea, the value of cultural assets is not satisfactory and the commercialization is not sufficient. Furthermore, most Jikji product designs on the market are simple and limited mainly for the old generation. The purpose of this study is to design fashion-cultural products suitable for young people who will be responsible for this cultural inheritance. The methods of this study were to make the design development through literature research and a case study for Jikji products on the market. For developing the products suitable for young people, 308 university students in Chungju were surveyed. To express end products, computer graphic program, Illustrator CS5, was used. The results of this study showed that the products on the market were not targeted for use by young people. The younger generations want modern and interesting design. Among the 8 design motives that are planned for design development, the most preferred motive numbers, 3, 7, and 8, were used. Design items, such as scarf, wallet and t-shirts, were selected by the result of survey and 3 scarves, 4 wallets, 3 t-shirts, a total of 30 items were developed. The designed products in this study can inform the cultural resource of Korea and contribute to raise the cultural value if they are commercialized.

• 한국수자원학회논문집
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• 제33권1호
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• pp.111-121
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• 2000

본 연구에서는 연속방정식, 운동량방정식, 2차흐름의 연직분포식, 횡방향 하상경사식 등을 이용하여 단일만곡수로 뿐만 아니라 연속만곡수로에서 흐름특성과 하상변동을 분석할 수 있는 수치모형을 계산하였다. 단일만곡수로에서는 흐름특성치와 하상변동을 실험치와 비교하였으며, 연속만곡수로에서는 최대유속의 이동경로를 Vadnal 수치모형의 계산치, Chang의 실험치와 비교하여 만족할 만한 결과를 얻었다. 중심각 $180^{\circ}$ 인 유로만곡부에서 고정상 및 이동상의 조건으로 실험을 실시하였으며, 하상재료로는 모래와 안트라싸이트를 선택하였다. 모래와 안트라싸이트의 경우에도 실험치와 계산치가 비교적 일치하고 있어서 하상재료가 변화되는 유로만곡부에서도 수치모형의 적용성을 확인하였다. 이 연구는 유로만곡부의 설계, 시공, 유지 및 관리 등에 필요한 흐름특성과 하상변동에 관한 기초자료를 제공할 것으로 생각된다.

• 한국습지학회지
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• 제19권2호
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• pp.181-192
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• 2017

침식 및 퇴적과 관련된 수치모형을 이용한 분석은 하천에 존재하는 보와 같은 수리구조물들의 유사이송을 연구하는데 중요한 요소이다. 본 연구에서는 다기능보들의 효과적인 운영을 위하여 낙동강수계에 위치해 있는 강정고령보를 대상으로 하상변동을 예측하였다. 2차원 모형은 CCHE2D를 이용하여 유사이송이 지배적으로 발생하는 다기능보 상 하류 구간 25km를 대상으로 침식과 퇴적에 대한 모의를 수행하였다. 2006년 태풍 "에위니아"사상을 대상으로 모형을 검 보정 하였으며, 모의결과와 관측값의 비교를 통하여 전체 모의구간에서 신뢰성 있는 결과가 도출되었다. 강정고령보가 건설된 이후 태풍사상에 의한 하상변동은 가동보 구간에서 상당히 증가하는 것으로 나타났고 하상변동은 유사의 재분배를 야기하였다.