• 전자공학회논문지SC
• /
• 제43권6호
• /
• pp.16-26
• /
• 2006

본 논문에서는 평판형 디스플레이 장치의 필수 구성품인 투명한 ITO(Indium-Tin-Oxide) 유리를 가공하기 위한 펨토초(Femto-second) 레이저 미세 가공의 효율을 극대화하기 위해 가공 대상체의 정보를 추출하는 시스템을 제안한다. 제안한 시스템은 레이저 스캐닝 시스템을 활용하여 펨토초 레이저빔의 초점 거리 오차와 각도 오차를 사전에 계측하고 3차원으로 형상을 복원한다. 본 시스템은 라인 스캔 레이저, 고해상도 카메라, 리니어 모션 가이드(Linear Motion Guide), 시스템 제어부로 구성되어있다. 또한 본 시스템의 모델링을 통한 카메라와 레이저의 위치와 측정 결과와의 관계를 나타낼 수 있는 민감도 지수를 정의하고, 이를 활용하여 더욱더 정확한 측정이 가능한 시스템을 설계할 수 있었다. 가공 대상체인 ITO 유리의 높이와 표면 형상을 측정하고 3차원으로 형상을 복원하여 주사 탐침 현미경(SPM)으로 얻은 결과와 비교하여 본 시스템의 성능을 검증하였다.

• Restorative Dentistry and Endodontics
• /
• 제46권1호
• /
• pp.3.1-3.14
• /
• 2021

Objectives: This study aimed to evaluate the interface between a calcium silicate cement (CSC), Biodentine and dental adhesives in terms of sealing ability. Materials and Methods: Microleakage test: 160 standardized class II cavities were prepared on 80 extracted human molars. The cavities were filled with Biodentine and then divided into 2 experimental groups according to the time of restoration: composite resin obturation 15 minutes after Biodentine handling (D0); restoration after 7 days (D7). Each group was then divided into 8 subgroups (n = 5) according to the adhesive system used: etch-and-rinse adhesive (Prime & Bond); self-etch adhesive 2 steps (Optibond XTR and Clearfil SE Bond); self-etch adhesive 1 step (Xeno III, G-aenial Bond, and Clearfil Tri-S Bond); and universal used as etch-and-rinse or self-etch (ScotchBond Universal ER or SE). After thermocycling, the teeth were immersed in a silver nitrate solution, stained, longitudinally sectioned, and the Biodentine/adhesive percolation was quantified. Scanning electron microscopic observations: Biodentine/adhesive interfaces were observed. Results: A tendency towards less microleakage was observed when Biodentine was etched (2.47%) and when restorations were done without delay (D0: 4.31%, D7: 6.78%), but this was not significant. The adhesives containing 10-methacryloyloxydecyl dihydrogen phosphate monomer showed the most stable results at both times studied. All Biodentine/adhesive interfaces were homogeneous and regular. Conclusions: The good sealing of the CSC/adhesive interface is not a function of the system adhesive family used or the cement maturation before restoration. Biodentine can be used as a dentine substitute.

• International Journal of Contents
• /
• 제8권3호
• /
• pp.34-41
• /
• 2012

The concept of vegetation freeboard equivalence (VFE) is presented from the comparison between the rise in stage with/without vegetation and the freeboard height under design discharge conditions. In South Korea, the freeboard height of large, medium and small rivers is defined as a function of river discharge. Two models are used for this analysis of flood stage with and without vegetation: the 1-D model HEC-RAS and the 2-D model RMA-2. Both models are applied to three river study sites of the Geum River in South Korea as representative sites for a large, a medium and a small river. The analysis shows that without vegetation, both models provide comparable results and the calculated results are in very good agreement with the design configuration. The vegetation effects on the medium river are less significant, and the freeboard is adequate to contain the rise in stage from the added floodplain vegetation in large rivers. The concept of vegetation freeboard equivalence is therefore useful for the analysis of flood river stages after the restoration of channels with increased floodplain vegetation.

• 대한심미치과학회지
• /
• 제17권1호
• /
• pp.23-30
• /
• 2008

Application of CAD/CAM is changing the way partial or full veneer all ceramic restoration is made. CAD/CAM systems, which were used mainly in other industries, have been developed and introduced for the dental purposes recently. It produced a flood of information on the CAD/CAM systems. It also influenced the development of restorative materials and all ceramic is substituting the traditional restorative materials of gold, composite resin and metal. Price increase of gold and other raw materials made the all ceramic more appealing. The introduction of a CEREC 3D system was innovative in several ways. Image of the prepared tooth is captured by camera and impression taking is unnecessary. Restoration can be delivered to the patient on one appointment and it will satisfy the demand of busy patients. One-day treatment with direct CAD/CAM system saves time compared to indirect CAD/CAM system. More superior restoration can be produced if lab work such as the adaptability check and shade selection is cooperated with lab technician. Short working time and comparably superior shade compatibility of color block was close to ideal. In the future, restorations with better quality can be fabricated in less time to busy patients thanks to the development of CAD/CAM system and dental materials.

• 상하수도학회지
• /
• 제27권5호
• /
• pp.661-669
• /
• 2013

River-water quality has been greatly improved during past several decades with the extraordinary expansion for the wastewater treatment capacities by the government. Research aims to select the priority restoration streams based on the chronicle data for tributaries in Geumgang watershed as the main stream area in the Chungchungnamdo province. The quality of BOD, phosphorus and percent of sewered population on 15 branch streams were compared by the grouping methods. The results of group D streams by category I that exceed 3.0 mg/L for BOD and 0.1 mg/L for phosphorus were Seuksung, Ganggyung and Bangchuk stream. The results of group D streams by category II that exceed 3.0 mg/L for BOD and less than 63.5 % of average percent of sewered population were Ganggyung, Gilsan, Bangchuk and Seuksung stream. The final results of selected streams drawn by the chronicle data which exceeded the standard quality and lower than the average percent of sewered population were Seoksung, Gangeyung and Bangchuk stream. The pollution of rivers in the down streams were more serious than in the upper streams. Their watersheds have to be improved river water quality, especially to extend sewer systems as well as wastewater treatment facilities.

• 한국측량학회지
• /
• 제22권1호
• /
• pp.21-27
• /
• 2004

다목적 대형 댐의 건설로 수몰된 과거의 삶의 공간을 20년이 지나서 다시 복원한다는 것은 그곳에 살던 실향민에게는 참으로 반가운 소식이다. 본 연구에서는 1980년대 초에 완공된 충주댐으로 인하여 물 속에 잠긴 청풍지구를 수몰이전의 입체 지형 공간적으로 원형복원하기 위한 원격탐사 기법을 적용한 것이다. 비교적 해상도가 좋은 인공위성 사진자료와 원격탐지된 디지털 영상자료를 수집하고, 수몰 직전에 제작된 지형도를 이용하여 위성영상자료의 통합 적용하여 수몰이전의 지형공간정보를 현재시간으로 영상 복원하는 실험을 한 것이다. 이를 위하여 지형도에서 추출한 등고선과 현재의 등고선과의 접목을 통하여 청풍 주변지역을 중심으로 당시의 수치표고모형을 생성하였다. 또한 이를 입체적으로 보여주기 위한 투시조감도를 각 방향에서 생성함으로서 수몰이전의 아름다운 모습을 3차원적으로 영상복원 하였다. 좀 더 가깝게 수몰마을을 보기 위한 근접 비행 시뮬레이션 동영상을 제작하여 과거 기억 속의 고향을 찾아볼 수 있도록 한 것이다. 이러한 실험적인 연구 결과로 새로운 퓨젼 영상의 생성에 의한 3차원 투시조감도의 생성과 근접방문이 가능한 비행시뮬레이션에 의한 과거 수몰된 댐 유역의 지형에 대한 영상복원이 가능하도록 하였다.

• 대한전자공학회논문지
• /
• 제17권3호
• /
• pp.20-25
• /
• 1980

Singular value decomposition을 통한 pseudo-inverse를 단층영상 재구성에 이용하였다. 본 논문에서는 SVD pseudo-inverse를 이용한 truncated inverse filter와 Scalar Wiener filter에 대하여 검토하고 각각에 대하여 통계적 측면에서의 최적화가 연구되었다. 이러한 방법은 신호와 잡음문에 trade-off를 기함으로써 재구성 문제에 항상 뒤따르는 ill-conditioning 현상을 극복할 수 있다. 본 논문을 통하여 구성된 filter의 성능을 확인하기 위하여 컴퓨터를 이용한 simulation이 이루어졌으며 그 결과 재구성된 협상은 만족할 만 하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 추계종합학술대회 논문집(4)
• /
• pp.89-92
• /
• 2000

In this paper, an effective image restoration using Genetic Algorithm(GA) in wavelet transform region is proposed. First, a wavelet transform is used for decomposition of a blurred image with white Gaussian noise as a preprocessing of the proposed method. The wavelet transform decomposes a degraded image into a wavelet subband coefficient planes. In this wavelet transformed subband coefficient planes, three highest subbands is composed entirely of noise elements on a degraded image. So, these subbands are removed. And remained subbands except for the lowest subband are individually applied to GA. For the performance evaluation, the proposed method is compared with a conventional single GA algorithm and a conventional hybrid method of wavelet transform and GA for a Lenna image and a boat image. As an experimental result, the proposed algorithm is prior to a conventional methods as each PSNR 3.4dB, 1.3dB.

• 대한두개안면성형외과학회지
• /
• 제23권4호
• /
• pp.178-182
• /
• 2022

Postoperative temporal hollowing is a common complication of craniotomy. Damage and repositioning of the temporalis muscle can lead to a depression in the temporal side of the skull with inferior bulging, worsening aesthetic outcomes. We report a case of cranioplasty with three-dimensional (3D) printed mesh involving an additional correction using a temporalis muscle sling to help address this problem. A 3D-printed bioabsorbable mesh was prepared based on preoperative facial computed tomography, and was fixed to the hollowed area for tissue augmentation. The temporalis muscle was elevated and fanned out to its original position, and a sling was attached to a screw that was fixed to the mesh. For reinforcement, an additional sling was attached to another screw fixed to the mesh 2-3 cm vertically above the first screw. Aesthetic results were confirmed immediately after surgery and later during outpatient follow-up. Both depression and lateral bulging were resolved, and there was no delayed drooping of the temporalis muscle on 6-month follow-up. There were no complications, and the patient was satisfied with the appearance. This is a simple yet effective technique with a low risk of complications, and should be considered for postoperative temporal hollowing patients, especially those with severe lateral bulging.

• 대한치과보철학회지
• /
• 제56권4호
• /
• pp.330-337
• /
• 2018

무치악 환자에게 임플란트 지지 고정성 보철수복 치료는 그 효용성이 검증되었으나, 복잡한 치료과정이 수반된다. 반면, 현대 치의학에서 디지털 기술력은 나날이 발전하여 현재 무치악 환자의 임플란트 수복치료까지 그 범위를 확장하였다. 본 증례에서는 66세 하악 무치악 환자의 임플란트 고정성 보철 수복에 대하여 진단부터 수술, 임시수복물 및 최종수복물의 디자인과 제작까지 디지털 시스템을 모든 단계에 이용하였다. 수술 전 진단단계에서 구강스캐너를 이용한 점막스캔과 환자의 안정적인 기존 총의치 교합을 토대로 임시수복물을 디자인하였다. 수술가이드를 이용하여 무절개 임플란트 식립 후에 사전제작한 임시수복물을 임플란트와 연결하여 즉시 임시수복물로써 사용하였다. 디지털 기술을 이용하여 안정적인 교합이 형성된 임시수복물의 수직고경과 중심위를 이전하여 최종수복물을 디자인 및 제작 하였다. 디지털 기술을 활용하여 환자의 수직고경과 교합을 보전하는 방법을 사용함으로써 무치악환자에서 복잡할 수 있는 임플란트 치료의 간단한 프로토콜을 정립하였기에 보고하는 바이다.