• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.11a
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• pp.370-373
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• 2007

지하구내에 물이 유입되기 시작하면 미리 설치되어 있는 펌프를 동작시켜서 배수를 해야한다. 이 경우 지하구내로 유입되는 물의 경로로 구분한 내수와 외수의 양을 알 수 있다면 위험도의 평가에 있어서 좋지만 유입량을 정확히 알 수 없으므로 시계열 분석으로 미래의 값을 예측하는 방법을 제시하고자 한다. 시계열 분석으로 예측한 값을 토대로 퍼지 이론을 이용한 지하구내 침수 상황 통제 시스템을 구현하였다.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.184-190
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• 2012

Purpose: The purpose of this study was to measure the absorbed dose and to calculate the effective dose for one periapical radiography using the portable and wall type dental X-ray machines. Materials and methods: Thermoluminescent chips were placed at 25 sites throughout the layers of the head and neck of a tissue-equivalent human skull phantom. The man phantom was exposed with the portable and wall type dental X-ray machines. For one periapical radiography taken by portable dental X-ray machine, the exposure setting was 60 kVp, 2 mA and 0.2 seconds, while for one periapical radiography taken by wall type dental X-ray machine, exposure setting was 70 kVp, 8 mA and 0.074 seconds. Absorbed dose measurements were performed and equivalent doses to individual organs were summed using ICRP 103 to calculate effective dose. Results: In the upper anterior periapical radiography using portable dental X-ray machine and in the lower posterior periapical radiography using both machines, the highest absorbed dose was recorded at the mandible body. The effective dose in upper anterior periapical radiography using portable and wall type dental X-ray machines was $4{\mu}Sv$, $2{\mu}Sv$, respectively. In the lower posterior periapical radiography, the effective dose for each portable and wall type dental X-ray machines was $6{\mu}Sv$, $2{\mu}Sv$. Conclusion: It was recommended that the operator use prudently potable dental X-ray machine because that the effective dose in the periapical radiography using wall type dental X-ray machine was lower than that in the periapical radiography using portable dental X-ray machine.

• 대한치주과학회:학술대회논문집
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• 2003.11a
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• pp.51-51
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• 2003

• Journal of Periodontal and Implant Science
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• v.15 no.1
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• pp.87.2-87.2
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• 1985

• Environmental Analysis Health and Toxicology
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• v.17 no.2
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• pp.141-145
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• 2002

Benfuresate의 잔류분석을 위해 GC-FPD(S-mode)를 이용하여 분석조건을 설정 중 열적 불안정으로 인해 열분해 산물과 모 화합물이 혼재됨이 확인되었다. 가스크로마토그라프를 이용한 열분해의 주된 요인은 주입구의 온도와 주입구내의 기화 정도인 것으로 판단되었으며, 주입구를 Chauhan과 Debre 가 고안한 on-column으로 교체 후 분석한 결과 분해산물이 없는 단일 봉우리의 크로마토그램을 얻을 수 있었고, 절대량으로 0.6-4ng의 정량 범위 내에서 유의성 높은 검량선을 얻을 수 있는 주입구 온도는 20$0^{\circ}C$였다.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.89-98
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• 2017

The aim of this study was to compared the penetration scores and microleakage levels of flowable resin in comparison to resin-based pit and fissure sealant. A total 120 extracted premolars were used and classified with group I (resin-based pit and fissure sealant), group II (flowable resin), group III (bonding agent + flowable resin), IV (fissurotomy + bonding agent + flowable resin) depending on the materials and the application methods. The penetration scores of the group treated with flowable resin following fissurotomy were similar to those of the group treated with resin-based sealant, but higher compared to those of the other groups treated with flowable resin without fissurotomy or bonding agent. The group treated with flowable resin following fissurotomy also exhibited the lowest microleakage levels. The group treated with resin-based sealant and the one treated with a bonding agent prior to the application of flowable resin showed similar microleakage levels. In conclusion, flowable resin may be applied as a pit and fissure sealant, and its application along with fissurotomy could increase the penetration scores.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.321-331
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• 2005

The purpose of this study was to compare the effectiveness of mechanical and acid treatment on enamel surfaces for the retention of pit and fissure sealants and evaluate the presence of a prismless layer. The etch pattern produced on enamel from immature and mature premolar teeth extracted with varying period of acid etching using 37% phosphoric acid was examined using a scanning electron microscope(SEM). The composition of each groups was evaluated using an energy dispersive x-ray(EDX) spectroscopy. The result of present study can be summarized as follows: 1. Prismless layer was commonly observed on the fissure enamel in young and mature premolar. 2. There were no differences in micro-structure and etching pattern on fissure enamel between the young and the mature premolar. 3. The most effective etching pattern for retention of pit and fissure sealant was observed in 60 seconds of etching time and no apparent difference of etching pattern was found among 15, 30, and 45 seconds of etching time which showed non-retentive etching patterns. 4. The etching pattern obtained by grinding enamel surface with bur followed by 60 seconds of etching was similar to that of 60 seconds of etching without any pretreatment of fissure surface. 5. Type 2 etching pattern was commonly found on fissure enamel in both young and mature premolar. 6. The calcium content and P/Ca ratio in fissure enamel between the young and the mature premolar were significantly different(P<0.05). But content of calcium, phosphate and P/Ca ratio on various regions of fissure enamel in both young and mature premolar did not showed any difference. Based on these results, prismless layer may negatively influence the retention of pit and fissure sealants. Therefore, the mechanical removal of the prismless layer by grinding prior to etching or by prolonged etching time of enamel within the fissure system should result in an improved bonding of a pit and fissure sealant.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.461-477
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• 1998

To evaluate the relapse pattern and long-term stabilities depanding on surgical methods following orthognathic surgery of Cl III patients, the author selected 24 subjects(10 male, 14 female) operated by SSRO and 26 subjects(10 male,16 female) operated by IVRO. Each subject took four lateral cephalograms : just before surgery(T1), within 48hrs after surgery(T2), 4-8 wks after surgery(T3), 6 month or more after surgery(T4), and the landmarks were digitized. The differences of relapse patterns in each interval between two groups were compared and the significance of correlation among the variables of each group was tested. The obtained results are as follows ; 1. Horizontal early relapse was forward movement of mandible in SSRO group, as compared to the backward movement in IVRO group, and there was a statistical significance between the two groups. 2. Vertical early and late relapses were decreases in anterior facial height in both groups and there was no statistical significance between the two groups. 3. There was a statistical significance in negative correlation between mandibular horizontal late relapse and surgical change of articular angle in SSRO group. 4. There was a statistical significance in negative correlation between amount of mandibular set-back and mandibular horizontal early relapse in both groups.

• Solar Energy
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• v.15 no.3
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• pp.59-73
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• 1995

The thermal analysis is accomplished with the route for the underground power transmission system which adopts the water pipe cooling with trough in tunnel. As a result, in case of a cooling system based on a refrigerator, the optimum condition for the flow rate of cooling water and the air velocity are calculated as the $2{\sim}3{\ell}/s/pipe$ and $1{\sim}2m/s/fan$, respectively. On the other hand, in case of cooling tower the optimum condition for them are calculated as the $2{\sim}3{\ell}/s/pipe$ and 6 m/s/fan, respectively. But the cooling system based on a cooling tower has the problem of enlarging the size of cooling fan and suppressing the labor of operator in tunnel. Therefore, to meet all the cooling conditions for a given cooling section, the cooling system based on a refrigerator is more acceptable.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.1
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• pp.83-91
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• 2004

The purposes of the study was to measure attitude and satisfaction concerning the service quality of university foodservices. The survey was conducted to 500 university students using questionnaires, of which 457 questionnaires were analyzed. A statistical data analysis was completed using SAS programs by the descriptive analysis. The results of the study were summerized as follows: 1) The mean frequencies of visiting the university foodservices per week were higher in males than females. The factor affecting the students on their first choice of the foodservices depended on the distance. The first complaint factor concerning the university foodservices was the taste of foods. 2) The students were not satisfied with the service quality of university foodservices personnels. The actual mean score of the service quality was 3.92 out of 5, but the perceived one was 2.94. Therefore, the satisfaction degree of the service quality was calculated as-0.98. 3) The students were more satisfied with the food quality of contracted foodservice management than that of self-operated one.