• Restorative Dentistry and Endodontics
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• v.31 no.1
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• pp.50-57
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• 2006

The purpose of this study was to investigate influence of each file step of $ProTaper^{(R)}$ system on canal transportation. Twenty simulated canals were prepared with either engine-driven $ProTaper^{(R)}$ or manual $ProTaper^{(R)}$, Group R-resin blocks were instrumented with rotary $ProTaper^{(R)}$ and group M-resin blocks were instrumented with manual $ProTaper^{(R)}$. Pre-operative resin blocks and post-operative resin blocks after each file step preparation were scanned. Original canal image and the image after using each file step were superimposed for calculation of centering ratio The image after using each file step alld image after using previous file step were superimposed for calculation of the amount of deviation. Measurements were taken horizontally at five different levels (1 2, 3, 4 and 5 mm) from the level of apical foramen. In rotary $ProTaper^{(R)}$ instrumentation group, centering ratio and the amount of deviation of each step at all levels were not significantly different (p>0.05). In manual $ProTaper^{(R)}$ instrumentation group, centering ratio and the amount of deviation of each step at all levels except of 1 mm were not significantly different (p>0.05). At the level of 1 mn, F2 file step had significantly large centering ratio and the amount of deviation (p<0.05). Under the condition of this study, F2 file step of manual ProTaper tended to transport the apical part of the canals than that of rotary $ProTaper^{(R)}$.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.435-440
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• 2004

연안침수지도는 태풍이나 해일에 의한 연안침수 발생 시 방조제의 월류 및 붕괴로 인한 예상 침수구역을 강우빈도(200년)별로 나타내고, 침수면적과 깊이를 표현한 지도로서 국외 선진국에서 방재형 국토관리 정책결정과 침수피해에 대한 대민 홍보의 수단으로 활용되고 있다. 국내에서도 연안침수에 의한 피해가 나날이 커지고 국토의 개발에 따른 자연 재해가 많아짐에 따라 보다 방재형 국토개발로 국민의 안전과 복리를 증진하고, 연안침수에 의한 피해를 최소화하기 위한 노력의 일환으로 연안침수지도의 제작 필요성이 증대되고 있다. 본 연구의 시범지역인 대부도 남부지역의 GIS 데이터베이스 구축은 문헌조사 및 기구축 데이터 확보, 지역의 특성에 맞는 신규 GIS 데이터베이스 구축 방법을 제시하였다. 침수구역을 예측하기 위한 모델링을 지원하기 위한 정확도와 경제성, 객관성, 현실성이 높은 지형공간자료의 효율적인 구축이 강조되었다. 구축한 데이터베이스의 세부 유형은 침수위험구역, 침수경계구역, 침수량 화살표이며, 기존에 구축된 데이터를 활용한 레이어는 해안선, 도로, 건물, 등고선, 등심선, 연안 표고점 측량데이터이다. 연안침수지도는 효율적인 재난관리를 위하여 다양하게 활용될 수 있을 것으로 사료되며 나아가 주민의 침수에 대한 경각심 고취와 사전 교육, 지방자치단체의 침수위험 관리업무의 활용이 가능할 것으로 사료된다. 본 연구에서 제작된 연안침수지도는 지자체 주민들을 위해 보기 쉽고 다양한 정보를 얻을 수 있도록 제작되었으며, 이를 위해 사진과 삽화를 추가하여 주민들에게 침수피해에 대한 경각심과 이해를 높이는데 중점을 두었다. 유지관리 후 활용체계 정비의 중요성’을 점검하고, ‘변동자료 발생원인의 분석’, ‘명확한 변동자료 입력 근거의 확보’, ‘갱신주체별 역할의 정의 및 유지관리 기준의 설정’, ‘분야별업무 특성을 고려한 관련 기준의 마련 및 타 시스템과 연계되는 항목을 고려한 절차 정의’ 등에 대한 다양한 접근을 시도하였다. 본 연구에서 제시하는 유지관리 모델을 기반으로 각 지자체별로 적절한 컨설팅이 진행되고 이에 따라 담당자의 실천이 이루어진다면 지자체 GIS의 투자대비 효과에 대한 기대는 이상이 아닌 현실로 다가오게 될 것이다.가오게 될 것이다. 동일하게 25%의 소유권을 가지고 있다. ？스굴 시추사업은 2008년까지 수행될 계획이며, 시추작업은 2005년까지 완료될 계획이다. 연구 진행과 관련하여, 공동연구의 명분을 높이고 분석의 효율성을 높이기 위해서 시료채취 및 기초자료 획득은 4개국의 연구원이 모여 공동으로 수행한 후의 결과물을 서로 공유하고, 자세한 전문분야 연구는 각 국의 대표기관이 독립적으로 수행하는 방식을 택하였다 ？스굴에 대한 제1차 시추작업은 2004년 3월 말에 실시하였다. 시추작업 결과, 약 80m의 시추 코아가 성공적으로 회수되어 현재 러시아 이르쿠츠크 지구화학연구소에 보관중이다. 이 시추코아는 2004년 8월 중순경에 4개국 연구팀원들에 의해 공동으로 기재된 후에 분할될 계획이다. 분할된 시료는 국내로 운반되어 다양한 전문분야별 연구에 이용될 것이다. 한편, 제2차 시추작업은 2004년 12월에서 2005년 2월 사이에 실시될 계획이다. 수백만년에 이르는 장기간에 걸쳐 지구환경변화 기록이 보존되어 있는

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.1
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• pp.29-38
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• 2012

The noise generated in the process of obtaining the medical image acts as the element obstructing the image interpretation and diagnosis. To restore the true image from the image polluted from the noise, the total variation optimization algorithm was proposed by the R.O. F (L.Rudin, S Osher, E. Fatemi). This method removes the noise by fitting the balance of the regularity and fidelity. However, the blurring phenomenon of the border area generated in the process of performing the iterative operation cannot be avoided. In this paper, we propose the adaptive total variation method by mapping the control parameter to the proposed transfer function for minimizing boundary error. The proposed transfer function is determined by the noise variance and the local property of the image. The proposed method was applied to 464 tooth images. To evaluate proposed method performance, PSNR which is a indicator of signal and noise's signal power ratio was used. The experimental results show that the proposed method has better performance than other methods.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5
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• pp.31-41
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• 2010

This research aims to present a methodological approach for repurposing small pockets of national/public lands, which can be constructed as parks, through an investigation of the present status of these areas of national/public lands that are scattered around Busan Megalopolis as well as the suitability of their construction. In order to attain this, this study looked at the present status of these small areas of national/public lands by utilizing a national land, city land list (lot number), land registration map and satellite image of Busan Megalopolis, and evaluating their suitability as parks through GIS analysis and classification. As a result, these small areas of lands with the potential to be turned into parks include 516 spots($375,934m^2$). Geographically, 39% of these areas are located on flat land and are the most scattered. 260 places met the requirements for optimal placement for conversion, while convenience included 305 places, and availability 267 places. The most optimal of the places meeting such standards include 61 spots. The characteristics of these areas of national/public lands include being below $500m^2$, with flatlands and open areas above a 5' grade occupy the highest ratio, accounting for 25.4% of the land studied. These results have offered a methodology for a GIS DB, which can visualize the data for a positive utilization be yond the simple level of the maintenance/preservation of national/public lands and provide basic data for the utilization and management of these types of areas in the future.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.17-40
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• 2000

Resin cements are used for cementing indirect esthetic restorations such as resin or porcelain inlays. Because of its limitations in curing of purely light cured resin cements due to attenuation of the curing light by intervening materials, dual cured resin cements are recommended for cementing restorations. The physical properties of resin cements are greatly influenced by the extent to which a resin cures and the degree of cure is an important factor in the success of the inlay. The purpose of this study was to evaluate the influence of porcelain thickness and exposure time on the polymerization of resin cements by measuring the microhardness and the degree of conversion, to investigate the nature of the correlation between two methods mentioned above, and to determine the exposure time needed to harden resin cements through various thickness of porcelain. The degree of resin cure was evaluated by the measurements of microhardness [Vickers Hardness Number(VHN)] and degree of conversion(DC), as determined by Fourier Transform Infrared Spectroscopy(FTIR) on one light cured composite resin [Z-100(Z)] and three dual cured resin cements [Duo cement(D), 3M Resin cement(R), and Dual cement(DA)] which were cured under porcelain discs thickness of 0mm, 1mm, 2mm, 3mm with light exposure time of 40sec, 80sec, 120sec, and regression analysis was performed to determine the correlation between VHN and DC. In addition, to determine the exposure time needed to harden resin cements under various thickness of porcelain discs, the changes of the intensity of light attenuated by 1mm, 2mm, and 3mm thickness of porcelain discs were measured using the curing radiometer. The results were obtained as follows ; 1. The values of microhardness and the degree of conversion of resin cements without intervening porcelain discs were 31~109VHN and 51~63%, respectively. In the microhardness Z was the highest, followed by R, D, DA. In the degree of conversion, D and DA was significantly greater than Z and R(p<0.05). 2. The microhardness and the degree of conversion of the resin cements decreased with increasing thickness of porcelain discs, and increased with increasing exposure time, D and R showed great variation with inlay thickness and exposure time, whereas, DA showed a little variation. 3. The intensity of light through 1mm, 2mm, and 3mm porcelain inlays decreased by 0.43, 0.25, and 0.14 times compared to direct illumination, and the respective needed exposure times are 53 sec, 70 sec, and 93 sec. In D and R, 40 sec of light irradiation through 2mm porcelain disc and 80 sec of light irradiation through 3mm porcelain disc were not enough to complete curing. 4. The microhardness and the degree of conversion of the resin cements showed a positive correlationship(R=0.791~0.965) in the order of R, D, Z, DA. As the thickness of porcelain discs increased, the decreasing pattern of microhardness was different from that of the degree of conversion, however.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.148-158
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• 1994

The purpose of this study was to compare the adaptation to tooth structure of light - cured glass ionomer cement with that of self -cured glass ionomer cement. In this study, class V cavities were prepared on the buccal surfaces of 10 extracted human premolar teeth, and teeth were randomly assigned 2 groups of 5 teeth each. The cavities of self-curing glass ionomer cement group were restored with the Fuji n. and the cavities of lightcuring glass ionomer cement group were restored with the Fuji II LC. The surfaces of glass ionomer cements were applied with All-Bond 2 adhesive, and cured with visible light. The restored teeth were stored in 100% relative humidity at $37^{\circ}C$ for 24 hours. And then. the roots of the teeth were removed with the tapered fissure bur and the remaining crowns were sectioned occlusogingivally through the center of glass ionomer restorations. Adaptation at tooth-restoration interface was assessed occlusally. axially, and gingivally by scanning electron microscope. The results were as follows : 1. On the occlusal margin, the group of self - curing glass ionomer cement showed closer adaptation to both enamel and dentin than the group of light-curing glass ionomer cement showing 5/lm gap between cement and tooth structure. 2. On the axial wall. the group of light-curing glass ionomer cement showing 5-$7{\mu}m$ gap between cement and dentin showed closer adaptation to dentin than the group of self -curing glass ionomer cement showing 10-$15{\mu}m$ gap between cement and dentin. 3. On the gingival margin, the group of light-curing glass ionomer cement showing 2-$5{\mu}m$ gap between cement and dentin(X 1200) showed closer adaptation to dentin than the group of self-curing glass ionomer cement showing 20pm gap between cement and dentin(X 600). 4. The group of self -curing glass ionomer cement showed closer adaptation on the occlusal margin than on the gingival margin, and the group of light-curing glass ionomer cement showed similar adaptation on both occlusal and gingival margins.

• Restorative Dentistry and Endodontics
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• v.34 no.3
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• pp.199-207
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• 2009

The objective of this study was to evaluate the effect of color measuring instrument by measuring the color of dental composite resins. Nine shade light cured composite resin disks were prepared (diameter : 15 mm, thickness : 4 mm). CIE $L^*a^*b^*$ color scale of each disk was measured with 3 different types of spectrophotometer [MiniScan XE plus (Model 4000S, Hunter Lab, USA), CM-3500d (Minolta, Japan) and Specbos 2100 Miniature VIS Reflection spectrometer (Serial No: 319416, JETI Technishe VIS Instrumentic GmbH. Germany)]. Miniscan XE Plus and CM-3500d using identical measuring geometry with different size of viewing aperture. But Specbos 2100 using different measuring geometry. Within the limitation of this study, there were color difference (${\Delta}E^*$) from 2.4 to 7.8 between Miniscan XE Plus and CM-3500d, but $L^*$, $a^*$, $b^*$ values showed the high correlation. However, there were great color difference (${\Delta}E^*$) in the extent of about 20 between instruments with the different measuring geometry. Therefore, color scale measured by color measuring instrument should be used as a relative value rather than an absolute value in the field of dentistry.

• Restorative Dentistry and Endodontics
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• v.30 no.6
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• pp.493-504
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• 2005

This study was performed to investigate the compatibility between 4 dentin adhesives and 4 resin luting cements. Dentin adhesives used in this study were All-Bond 2 (Bisco Inc., Schaumbrug, IL, USA), Clearfil SE-Bond (Kuraray Medical Inc, Osaka, Japan), Prompt L-Pop (3M Dental Products, St. Paul, MN, USA), One-Up Bond F (Tokuyama corp., Tokyo, Japan) Resin luting cements used in this study were Choice (Bisco Inc., Schaumbrug, IL, USA), Panavia F (Kuraray Medical Inc, Osaka, Japan), RelyX ARC (3M Dental Products, St. Paul, MN, USA) Bistite II DC (Tokuyama corp., Tokyo, Japan). Combination of each dentin adhesive and corresponding resin cement was made to 16 experimental groups. Flat dentin surfaces was created on mid-coronal dentin of extracted mandibular third molars, then dentin surface was polished with 320-grit silicon carbide abrasive papers. Indirect resin composite block (Tescera, Bisco) was fabricated. Its surface for bonding to tooth was polished with silicon carbide abrasive papers Each dentin adhesive was treated on tooth surface and resin composite overlay were luted with each resin cement. Each bonded specimen was poured in epoxy resin and sectioned occluso-gingivally into 1.0mm thick slab, then further sectioned into $1.0{\times}1.0mm^2$ composite-dentin beams. Microtensile bond strength was tested at a crosshead speed of 1.0mm/min. The data were analysed by one-way ANOVA and Duncan's multiple comparison tests The results of this study were as follows, 2-step self-etching dentin adhesive which has additional bonding resin is more comparison than tests. self-etching dentin adhesive.

• Journal of the Korea Society of Computer and Information
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• v.25 no.4
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• pp.165-172
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• 2020

In this paper we propose an uses on-device-based edge computing technology and big data analysis methods through the use of on-device-based edge computing technology and analysis of big data, which are distributed computing paradigms that introduce computations and storage devices where necessary to solve problems such as transmission delays that occur when data is transmitted to central centers and processed in current general smart factories. However, even if edge computing-based technology is applied in practice, the increase in devices on the network edge will result in large amounts of data being transferred to the data center, resulting in the network band reaching its limits, which, despite the improvement of network technology, does not guarantee acceptable transfer speeds and response times, which are critical requirements for many applications. It provides the basis for developing into an AI-based facility prediction conservation analysis tool that can apply deep learning suitable for big data in the future by supporting intelligent facility management that can support productivity growth through research that can be applied to the field of facility preservation and smart factory industry with integrated hardware technology that can accommodate these requirements and factory management and control technology.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.2
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• pp.81-89
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• 2019

Purpose: This study aimed to investigate the correlation between the solubility and the amount of fluoride release when a resin surface coating agent is applied to RMGIC. Materials and Methods: To measure the fluoride release and solubility, Fuji II $LC^{(R)}$and $Filtek^{TM}$ Z350XT without a surface coating, Fuji II $LC^{(R)}$ with G coat $plus^{TM}$ and Fuji II $LC^{(R)}$ with $Permaseal^{(R)}$ were prepared. And the amount of fluoride release and solubility were measured. Results: There was no significant difference in the daily fluoride release between the surface coating agents. The cumulative fluoride release was significantly different between the groups using RMGIC at 56 days (P < 0.05). In the solubility measurement, RMGIC without surface coating was significantly different only on the 7th day compared to the other three groups (P < 0.05). Conclusion: Surface coating agents can prevent the degradation of properties by the initial solvent in RMGIC. Therefore, fluoride is preserved inside the restorative material and the effect of surface coating after the addition is reduced, so that the effect on fluoride release and storage is also reduced.