• 가정과삶의질연구
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• 제27권2호
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• pp.123-138
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• 2009

The purpose of this study was to investigate the social inclusion of permanent rental and lot-sold apartment and to provide basic source of their physical and social inclusion. The research method was in-depth interview for 32 residents in two apartment complex based on the social inclusion index developed in the previous study. The results of the study were summarized as follows: First, the majority of the residents' average monthly income in the permanent rental apartment were lower than the minimum cost of living. But, they were not seriously realized it and gave up any economic activities due to their poor health and age. Second, the big different indexes from the residents in lot-sold apartment were the family networks and social activity participations. They were not satisfied with their family members, seldom had social gatherings, and did not have any information of community cultural events. Third, since they had narrow sphere of activities, they could not properly evaluate the diversity of neighborhood facilities and the convenience of public transportations. But, they obviously recognized anti-social behaviors and the invasion of the privacy in the apartment complex, and maintained superficial neighborship. Fourth, on the other hand, the residents in lot-sold apartment had the feeling of being harmed by the various troubles of the permanent rental apartment.

• Smart Structures and Systems
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• 제6권3호
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• pp.197-209
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• 2010

The structural state of a bridge is currently examined by visual inspection or by wired sensor techniques, which are relatively expensive, vulnerable to inclement conditions, and time consuming to undertake. In contrast, wireless sensor networks are easy to deploy and flexible in application so that the network can adjust to the individual structure. Different sensing techniques have been used with such networks, but the acoustic emission technique has rarely been utilized. With the use of acoustic emission (AE) techniques it is possible to detect internal structural damage, from cracks propagating during the routine use of a structure, e.g. breakage of prestressing wires. To date, AE data analysis techniques are not appropriate for the requirements of a wireless network due to the very exact time synchronization needed between multiple sensors, and power consumption issues. To unleash the power of the acoustic emission technique on large, extended structures, recording and local analysis techniques need better algorithms to handle and reduce the immense amount of data generated. Preliminary results from utilizing a new concept called Acoustic Emission Array Processing to locally reduce data to information are presented. Results show that the azimuthal location of a seismic source can be successfully identified, using an array of six to eight poor-quality AE sensors arranged in a circular array approximately 200 mm in diameter. AE beamforming only requires very fine time synchronization of the sensors within a single array, relative timing between sensors of $1{\mu}s$ can easily be performed by a single Mote servicing the array. The method concentrates the essence of six to eight extended waveforms into a single value to be sent through the wireless network, resulting in power savings by avoiding extended radio transmission.

• Journal of Radiation Protection and Research
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• 제46권3호
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• pp.106-111
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• 2021

Background: Crookes tube is utilized in junior high and high schools in Japan to study the character of electrons and current, and not for radiological education. There is no official guideline or regulation for these radiation source to the public. Therefore, most teachers have no information about the leakage of X-rays from Crookes tube. The peak energy of X-rays is approximately 20 keV, and it is impossible to measure using conventional survey meters. Materials and Methods: Each leakage dose of low energy X-rays from 38 Crookes tube in the education field, such as junior and senior high schools in Japan, was explored by the teachers in the school using radio-photoluminescence (RPL) dosimeters. Before and after the measurements, the dosimeters were sent by postal mails. Results and Discussion: At the exploration in this study, it was estimated that the 70 ㎛ dose equivalent, H_p(0.07) of X-rays from 31 Crookes tubes were smaller than 100 µSv in 10 minutes, at the distance of 1 m, where the Crookes tube was usually observed. However, the highest dose was estimated as 0.69 mSv by an equipment with the full power. Furthermore, one Crookes tube exhibited 0.62 mSv with minimum output power of the induction coil. This relatively large dose was reduced by the shorter distance of discharge electrodes of the induction coil. Conclusion: The leakage dose of low energy X-rays from 38 Crookes tube was explored using RPL dosimeters. It was estimated that the H_p(0.07) of X-rays from 31 Crookes tubes were smaller than 100 µSv in 10 minutes at the distance of 1 m, while some equipment radiated a higher dose. With this study, the provisional guideline for the safety operation of Crookes tube is established.

• 한국산업보건학회지
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• 제27권4호
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• pp.361-370
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• 2017

Objectives: This study evaluated the diesel engine exhaust (DEE) exposure levels of door-to-door deliverers in Daegu from July to September. Methods: We measured exposure levels of DEE surrogates for the same door-to-door deliverers who joined the particulate matter 2.5 exposure study previously published in this journal. Black carbon(BC) concentrations were measured using real-time BC monitoring devices with 1 minute interval. $NO_2$ concentrations were monitored using passive badges. DEE exposure data were analyzed using the same characteristics and GPS information as the first study. Results: A total of 40 measurements of BC concentrations and $NO_2$ concentrations were collected during delivery of parcels. The average exposure levels to BC, and $NO_2$ were $2.23{\mu}g/m^3$ ($0.001-350.85{\mu}g/m^3$) and 21.26 ppb(3.3-61.37 ppb), respectively. Exposure levels to BC according to the day of a week and coverage areas were not significantly different(p>0.05). Delivery trucks manufactured before 2006 caused significantly higher exposure to BC than the trucks manufactured after 2006(p<0.05). Exposure levels of BC integrated for each time in residential area and roadsides were $1.96{\mu}g/m^3$ and $3.46{\mu}g/m^3$, respectively, and the difference was statistically significant(p<0.001). The Pearson correlation coefficients between the ambient $PM_{2.5}$ and BC was significant, r=0.26(p<0.01); however, the correlations between $PM_{2.5}$ and ambient $PM_{2.5}$, and between BC of DEE and $PM_{2.5}$ of DEE did not show a significant correlation Conclusions: BC and $NO_2$ exposure levels were significantly lower when door-to-door deliverers drove newer trucks. BC exposure levels of deliverers were higher in roadsides than in residential area. DEE from nearby vehicles through open windows might be the main source of BC exposure.

• 한국지능시스템학회논문지
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• 제24권1호
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• pp.96-101
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• 2014

풍력은 전 세계적으로 가장 각광을 받고 있는 신재생 에너지이며 당분간 이러한 추세는 계속될 것으로 기대되고 있다. 최근 풍력발전시스템의 O&M(Operation & Maintenance) 비용의 절감에 대한 필요성이 꾸준히 대두되고 있는 실정이다. O&M 비용의 절감을 위한 가장 효율적인 방법은 CMS(Condition Monitoring System)의 도입이며 이는 풍력발전기 부품들의 악화, 적절한 선제적 유지보수, 발전중지시간의 단축 및 궁극적으로 풍력발전기의 운전 효율을 증대시키는 것을 가능케 한다. 풍력발전기의 터빈 로터와 관련하여 질량 불평형 및 공력비대칭과 같은 고장이 발생될 수 있다. 일반적으로 이러한 고장은 다양한 형태의 진동을 야기 시킨다. 이에 본 연구에서는 진동신호에 대한 스펙트럼과 간단한 max-min 진단 로직으로 구성된 고장검출 알고리즘을 제안한다. 또한 제안된 진단기법의 유용성의 확인을 위해 GH-Bladed 프로그램을 이용한 다양한 시뮬레이션 고찰을 수행한다.

• 대한가정학회지
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• 제49권10호
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• pp.29-37
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• 2011

The principal objective of this study was to evaluate the consumption patterns, the importance of product properties, and the satisfaction levels of blackberry and mulberry fruit beverage products(BMBPs) in the Jeonbuk area, Korea. Self-administered questionnaires were collected from 294 customers(male 40.8%, female 59.2%) residing at Jeonju in Jeonbuk area. Descriptive and comparative statistical analyses were completed using SPSS PC program(version 19.0). Approximately, 61.6% of participants consumed BMBPs 1-2times a year. Only 1.7% of participants consumed BMBPs everyday. The main information source about BMBPs was 'families/friends'. About 58.8% of participants responded that the main reason for purchasing BMBPs was 'for health'. The result indicated the overall importance level(3.94) was higher than the satisfaction level(3.41)(p < .001). The importance and satisfaction levels of the older group (50's) were significantly higher than the levels of younger group(20-30's)(p < .01 ; p < .05). According to the IPA(Importance-Performance Anslysis), 'price' and 'credibility' of companies were the most important properties that had to be changed as soon as possible to increase satisfaction with BMBPs. Therefore, to increase BMBPs'-consumption, quality improvements on these products through cooperation between BMBPscompanies, the regional government, and research institutions are necessary.

• 한국실내디자인학회논문집
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• 제17권3호
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• pp.111-122
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• 2008

As Korea has undergone rapid modernization, urbanization and industrialization, women's social participation has increased. Accordingly, child care facilities have shown continuous growth in numbers. However, according to research, child care facilities in Korea lag behind those in other nations in terms of quality. Given that, it seem urgent to enhance the quality of child care facilities and improve their indoor environment. Above all, overall atmosphere, colors and finishing materials are connected directly with educational effects as well as feelings and health of facility users. This study assesses the current state of child care facilities and preferences by focusing primarily on interior atmosphere, materials and colors. For This Study, 7 facilities were surveyed, and 46 subjects were participated for this study. The findings suggest that "pretty" style is preferred to "natural" style. As regards flooring material, wood floor is preferred. It is recommended to lay pastel colored carpet or PVC flooring material to the wood floor. As for wall, it is desirable to divide the wall spaces by adding wood and painting to simple wallpapers. In case of the ceiling noise absorptive material is recommended to use instead of wallpapers. For the doors, it is desirable to use contrasting materials and colors given accessibility for children. In the meantime, rather than strong primary colors, soft color or pastel colors are desirable for furniture. This study has limitations because of insufficiency of case study samples. However, it is significant in that the study results may be used as primary source of information to improve the environment of child care facilities.

• 환경분석과 독성보건
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• 제21권4호
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• pp.237-242
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• 2018

Strontium (Sr) commonly exists in rock, groundwater, soil, plants, and animals. The Sr isotope ratio offers important information as a tracer on nature because the Sr isotopic composition is not fractionated by any biological process in these ecosystems. Hence, Sr isotope ratio has been used in several studies on tracing the Sr source for contaminated sites and human migration. In this study, we developed a separation method for Sr content, and then improved Sr isotope analysis using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). A powdered rock standard (NIST 2710a) was used to determine the removal of interference elements (Rb and Ca) and the recovery rate of Sr content. The results ranged from 98% to 106%. Additionally, three standard samples (NBS 987, IAPSO and NIST 1486) were analyzed to evaluate the precision and accuracy of the results. The measured $^{87}Sr/^{86}Sr$ ratio for all the samples were consistent with the reported values, within an error. These results indicate that our established Sr separation and Sr isotope measurement methods are reliable and can hence be useful in the fields of environmental and forensic sciences.

• 한국항해항만학회지
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• 제32권3호
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• pp.215-221
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• 2008

구조물의 대표적 동적특성인 고유진동수 및 모드형상은 손상평가, 구조계추정기법 등과 결합한 구조건전성 평가분야에서 매우 중요한 기초 자료로 활용되고 있다. 그러나 해양구조물이나 대경간 교량과 같은 대형 구조물의 경우 진동원을 정확히 계측하기 힘들기 때문에 소규모의 구조물에 많이 쓰이는 기존의 모달 테스트 기법으로는 구조물의 진동특성을 구할 수 없다. 본 논문에서는 경간이 긴 대형 트러스 구조물을 대상으로 가속도 응답만으로 고유진동수 및 모드형상을 추출할 수 있는 방법을 연구하였다. 트러스 구조물의 수치해석 모델을 이용하여 가속도 응답 및 주파수 응답함수의 생성과정, 모드분석을 통한 고유진동수 및 모드형상 추출과정을 상세히 설명하였다. 제안한 방법으로 얻은 모드형상은 고유치 해석으로부터 계산된 모드형상과 비교하여 정확성을 검증하였으며, 모의 손상을 통한 손상평가기법에 적용하여 타당성을 입증하였다.

• 한국산학기술학회논문지
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• 제14권8호
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• pp.3876-3886
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• 2013

본 연구는 성행동, 부모 및 친구와의 성 의사소통, 성태도 및 성지식 정도와 성행동에 영향을 미치는 요인을 파악함으로써 성건강 향상을 위한 성교육 프로그램의 기초자료를 제공하고자 시도되었으며, 2012년 3-4월 서울과 천안 소재 2개 간호대학에 재학 중인 간호대학생 218명의 설문지를 분석하였다. 연구결과 간호대학생의 성행동, 부모 및 친구와의 성 의사소통, 성태도 및 성지식 정도는 중간이상인 것으로 나타났다. 성행동은 부모와의 성 의사소통, 성태도 및 성지식과 부적상관관계를 나타내었고, 간호대학생의 성행동에 영향을 미치는 요인은 성 관련 정보의 출처, 성지식, 과거 이성교제 경험, 부모와의 성 의사소통 순으로 나타났다. 성문제는 삶의 다양한 측면에 영향을 미치므로 간호사는 성문제를 가지고 있는 대상자를 간호할 때 성문제에 대한 깊은 이해를 가질 필요가 있다. 따라서 간호대학생을 위한 성교육 프로그램은 부모와 친구를 포함한 개인간 접근 전략을 요구하며, 간호대학생 스스로 성건강 관리에 적극적으로 나설 수 있도록 유도해야 할 것이다.