• 한국대기환경학회지
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• 제18권6호
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• pp.527-538
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• 2002

In this study, the performance of sampling and of analytical methodology was examined against a number of selected volatile organic compounds (VOCs) in the ambient air. The canister-based sampling method for VOCs has been a viable and widely used approach that is based on research and evaluation performed over the past several years. VOCs were determined using canisters by GCMSD analysis. A total of target analyses in this study included approximately 30 VOCs designated in TO-l4A categories including BTEX. The methodology for QC(quality control) was intensively investigated with a wide range of performance criteria such as; (1) cleanliness of canisters, (2) reproducibility of diluter, (3) instrumental detection limits of preconcentrator and GCMSD, and (4) precision and accuracy of GCMSD. For most of the compounds tested, precision was less than $\pm$5%, IDL was 0.2 ppbv, accuracy was $\pm$5%, respectively. This study demonstrated that the combination of canister sampling and GC/MSD analysis could be reliably applied to the measurements of BTEX in ppbv levels that are typically observed in/outdoor air environment.

• 한국인터넷방송통신학회논문지
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• 제14권4호
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• pp.127-132
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• 2014

본 논문에서는 키넥트를 이용하여 디지털 사이니지의 스크린을 터치하지 않으면서 화면의 내용을 제어하거나 원하는 파일을 개인 스마트 단말기로 다운로드 할 수 있게 방법을 제안 구현하였다. 제안 방법의 특징 및 기여도는 다음과 같다. 첫째, 세균감염의 위험이나 스크린의 불청결 등의 문제를 해결하고 상호작용에 의한 광고효과를 극대화 할 수 있다. 둘째, 우리가 흔히 보는 스크린광고에서 내가 보기를 원치 않는 광고를 화면을 터치하지 않고 다른 광고로 넘김으로써 컴퓨터와의 일방적인 소통이 아닌 쌍방으로 소통할 수 있다. 성능평가결과 제안된 방법은 효과적으로 작동됨을 확인 하였다. 특히, 사용자의 행위인식을 통해 일정 좌표범위 내에 커서가 들어갔을 경우 동작하고, 정보를 다운로드 할 경우 서버 PC의 성능과 개인 스마트 단말기의 버전에 따라 파일전송시간이 달라진다.

• 한국조경학회지
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• 제30권2호
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• pp.12-22
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• 2002

This study examines the visitors'evaluations of tourism resources in Insa-dong, which the Seoul metropolitan government has improved recently. This study adopted the method of Importance-Performance Analysis by collecting data through questionnaires. A random sampling of visitors to Insa-dong was conducted in June and July,2001. The survey included questions on the physical and psychological components of Insa-dong's tourism resources. In the case of physical components, eight factors(ancient arts shop, art gallery, atelier, calligraphy shop, pottery arts, traditional tea house, antique shop, traditional clothes) out of thirteen were categorized as 'keeping up the good work'. None of the Physical components was shown as 'low priority'or'possible overkill'. In particular, four factors(restaurant, heritage, Korean-style house and alley, traditional cultural festival) need to be impoved most urgently in terms of visitors'satisfaction. Survey results realize them as high priority in importance but low in performance, thereby designated as, 'concentrate here'. An image of the 'street' showed to be high in importance and identical in performance, so can be categorized between'keeping up the good work'and 'concentrate here'. The results show that unusual outdoor spaces and the festivals of Insa-dong have a significant meaning to the visitors. In the case of psychological components, three factors(general atmosphere experience of unusual atmosphere, appropriateness of stroll time) out of seventeen were categorized as 'keeping up the good work'. Ore factor (shopping) was designated as 'low priority'and not found to be 'possible overkill'. Thirteen factors (various events, possibility of various activity, various flood, richness of play, new experience, education cultural inheritance, parking facilities, resting places, green spaces, meeting places, guide map and information, cleanliness of facilities/convenience) need to be improved mast urgently in terms of visitors' fulfillment. They are perceived as areas of 'concentrate here'. This confirms that attractive events are essential for the recent visitor satisfaction. Furthermore, visitors are not satisfied with its amenity and acccss in Insa-dong despite the improvements. In conclusion, positive impressions, both physical and psychological, should be maintained while factors mentioned to be lacking should be prioritized in order of necessity to improve the image of Insa-dong and solutions need to be found and implemented. The results of this study would be helpful in the planning and management of nsa-dong considering the visitors'requirements.

• Korean Chemical Engineering Research
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• 제48권3호
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• pp.401-404
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• 2010

본 연구에서는 PCB의 먼지 제거용 세정제로 사용되는 스프레이형 세정제를 선정하였다. 전자 반도체 부품의 세정에서 분무 세정의 원리를 적용시킨 제품의 분사력을 평가하기 위해 기판(IPC-A-36)을 사용하여 세정제를 분사하여 분사시간에 따라 그 이동거리를 비교하였다. 철가루와 먼지를 오염물, 기판(IPC-A-36)을 시편으로 하여 일반시험 평가법의 방법 중 가장 보편적으로 쓰이는 중량법으로 오염물에 따른 세정성능을 측정하여 비교하였다. 기판의 이동거리는 분사 시간이 늘어남에 따라 증가하였다. 1회 세정 시(3초간 분사) 먼지와 철가루는 오염물의 양이 증가함에 따라 세정효율이 감소하였고 특히 먼지 오염물은 매우 급격한 세정효율의 감소를 보였다.

• Restorative Dentistry and Endodontics
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• 제48권4호
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• pp.36.1-36.15
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• 2023

Objectives: This study aimed to compare the effectiveness of a single-file reciprocating system (WaveOne Gold, WOG) and a multi-file rotary system (ProTaper Universal Retreatment, PTUR) in removing canal filling from severely curved canals and to evaluate the possible adjunctive effects of XP-Endo Finisher (XPF), the Self-Adjusting File (SAF), and an erbium, chromium: yttrium, scandium, gallium garnet (Er,Cr:YSGG) laser using microcomputed tomography (µCT). Materials and Methods: Sixty-six curved mandibular molars were divided into 2 groups based on the retreatment technique and then into 3 based on the supplementary method. The residual filling volumes and root canals were evaluated with µCT before and after retreatment, and after the supplementary steps. The data were statistically analyzed with the t-test, Mann-Whitney U test, analysis of covariance, and factorial analysis of variance (p < 0.05). Results: PTUR and WOG showed no significant difference in removing filling materials (p > 0.05). The supplementary techniques were significantly more effective than reciprocating or rotary systems only (p < 0.01). The supplementary steps showed no significant differences in canal filling removal effectiveness (p > 0.05), but XPF showed less dentin reduction than the SAF and Er,Cr:YSGG laser (p < 0.01). Conclusions: The supplementary methods significantly decreased the volume of residual filling materials. XPF caused minimal changes in root canal volume and might be preferred for retreatment in curved root canals. Supplementary approaches after retreatment procedures may improve root canal cleanliness.

• 한국치위생학회지
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• 제9권2호
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• pp.147-163
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• 2009

This study was attempted in order to look into 'Assist work' as to Implant system which dental hygienists perform in a clinical field. Subjects of this research were 362 dental hygienists who work at general hospital, University hospital, dental hospital, and dental clinics located in Seoul, Kyeong-gi, In-chon, and Jeon-buk area. As to research tool, we produced questionnaire which was comprised of the total 25 items regarding 3 of general features (age, career of dental hygienist, and personality), 6 of implant system assist work, 3 of Informed consent before surgery, 6 of preoperative preparation and maintenance related business, and 7 items related to postoperative maintenance. By using SPSS program, collected data was analyzed. Results of analysis in this study were as follow; 1. As to implant related education, dental hygienists' experience of education was high as 77.7%, and the people who is needed more education was 86.3%. Consequently, dental hygienists' concern about the implant related education was very high. 2. It was observed that most of informed consent making approvement by announcement to the surgical operation was made by dental hygienist before implant as 95%. 3. Over 80% of dental hygienists performed acquisition of cleanliness technology, motivation, back up articles preparation, treatment area arrangement, and etc. which we can check by preoperative maintenance items. In particular, response about the motivation was very high as more than 90%. 4. When performing an operation, in the case of disinfecting finger was low for 53.9% and the method was mainly washing with drug solution, and gown sterilization was performed only in 52.2%. Therefore education regarding disinfection was urgently needed. 5. Significance of education could be known that answers of hygienists experienced education appeared highly in items of maintenance method and there was statistically significant difference(p<0.05). 6. In case that assist work were 21cases or greater, agitation measurement was the most many performed in 68.9% and difference was showed up significantly(p<0.001). 7. Evaluation about periodontal tissue was high in dental hygienists who had experienced education and also there was statistically significant difference. In conclusion, assist work of dental hygienists was very comprehensive when implant surgery was performed, and all of items excluding hand disinfection or gown disinfection were highly showed up in most of hygienists. However, since there is the limit that we didn't investigate the quality of performing contents. It is considered that further study regarding the content has to be progressed for supporting this result in the future.