• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.173-180
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• 2020

PURPOSE. This study compared digital (reference point matching) and replica methods for measuring marginal and internal fit of full coverage restorations. MATERIALS AND METHODS. A maxillary left first molar typodent was fixed on to an aluminum base and prepared to receive all-ceramic full coverage restoration. The model was scanned with an intraoral scanner (CEREC Omnicam, Sirona, York, PA, USA). Twelve crowns were fabricated from lithium disilicate blocks (IPS emax CAD, Ivoclar Vivadent) and then crystalized. Marginal and internal fit of each restoration was measured by two examiners using replica and a new digital three-dimensional technique. Reliability between the two methods and two examiners was assessed by correlation and Cronbach's Alpha coefficient (P<.05). A Bland-Altman assessment for agreement was used to compare the two methods. RESULTS. Bland-Altman assessment showed that the mean of difference for marginal, absolute marginal, and axial gap was respectively -1.04 ㎛, -41.9 ㎛, and -29.53 ㎛ with limit of agreement (LOA) between -37.26 to 35.18 ㎛ for marginal, -105.85 to 22.05 ㎛ for absolute marginal and -80.52 to 22.02 ㎛ for axial gap. Positive correlation for repeatability (P<.05) in determining marginal and internal gaps by the two examiners in both techniques was revealed. Reliability of both techniques in all sites of measurements was at least good (0.8 ≤ α < 0.9). CONCLUSION. Both measuring techniques appeared highly reliable for evaluating fit of fixed dental restorations, while reference point matching provided higher values in axial and absolute marginal gap assessment.

• The Journal of Advanced Prosthodontics
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• 제9권5호
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• pp.358-363
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• 2017

PURPOSE. The purpose of this study was to evaluate the reliability of computer-aided replica technique (CART) by calculating its agreement with the replica technique (RT), using statistical agreement analysis. MATERIALS AND METHODS. A prepared metal die and a metal crown were fabricated. The gap between the restoration and abutment was replicated using silicone indicator paste (n = 25). Gap measurements differed in the control (RT) and experimental (CART) groups. In the RT group, the silicone replica was manually sectioned, and the marginal and occlusal gaps were measured using a microscope. In the CART group, the gap was digitized using optical scanning and image superimposition, and the gaps were measured using a software program. The agreement between the measurement techniques was evaluated by using the 95% Bland-Altman limits of agreement and concordance correlation coefficients (CCC). The least acceptable CCC was 0.90. RESULTS. The RT and CART groups showed linear association, with a strong positive correlation in gap measurements, but without significant differences. The 95% limits of agreement between the paired gap measurements were 3.84% and 7.08% of the mean. The lower 95% confidence limits of CCC were 0.9676 and 0.9188 for the marginal and occlusal gap measurements, respectively, and the values were greater than the allowed limit. CONCLUSION. The CART is a reliable digital approach for evaluating the fit accuracy of fixed dental prostheses.

• 대한치과보철학회지
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• 제54권3호
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• pp.210-217
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• 2016

목적: 본 연구의 목적은 실제 환자에서 디지털 구강스캐너로 모형 없이 제작한 보철물의 변연 및 내면 적합도를 평가하는 것이다. 대상 및 방법: 전향적 임상시험으로 시행한 본 예비 연구는 총 11개의 수복물을 대상으로 하였다. 구강스캐너(TRIOS, 3shape, Copenhagen, Denmark)로 디지털 구강인상을 채득한 후, 캐드 디자인 및 밀링 가공 과정을 통해 전부지르코니아 수복물을 제작하였다. 완성된 지르코니아관을 환자 구강 내에 시적하였고, 레플리카 술식으로 보철물-지대치 복제물을 얻었다. 이를 근원심, 협설 방향으로 잘라 변연오차, 변연간극과 축벽부, 선각부, 교합면부의 내면간극을 측정하였다. 통계처리는 Kruskal-Wallis 검정과 Mann-Whitney U 검정을 이용하여 통계적 유의성을 분석하였다(${\alpha}=.05$). 결과: 복제물을 통한 적합도 분석 결과, 근원심, 협설 절편 사이에는 통계적으로 유의한 차이가 없었다(P>.05). 변연간극에 불일치가 있었으며, 변연 오차가 변연간극 보다 컸다(P<.01). 결론: 본 연구의 한계 내에서, 구강스캐너로 모형 없이 제작한 전부지르코니아 수복물의 적합도는 임상적으로 허용할만한 결과를 보였다. 그러나 지르코니아관의 변연부위가 과풍융되는 경향이 있었으므로 주의 깊은 임상 적용 및 추적 연구가 요구된다.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.189-194
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• 2024

This paper presents a radiation-hardened-by-design preamplifier that utilizes a self-compensation technique with a charge-sensitive amplifier (CSA) and replica for total ionizing dose (TID) effects. The CSA consists of an operational amplifier (OPAMP) with a 6-bit binary weighted current source (BWCS) and feedback network. The replica circuit is utilized to compensate for the TID effects of the CSA. Two comparators can detect the operating point of the replica OPAMP and generate appropriate signals to control the switches of the BWCS. The proposed preamplifier was fabricated using a general-purpose complementary metal-oxide-silicon field effect transistor 0.18 ㎛ process and verified through a test up to 230 kGy (SiO₂) at a rate of 10.46 kGy (SiO₂)/h. The code of the BWCS control circuit varied with the total radiation dose. During the verification test, the initial value of the digital code was 39, and a final value of 30 was observed. Furthermore, the preamplifier output exhibited a maximum variation error of 2.39%, while the maximum rise-time error was 1.96%. A minimum signal-to-noise ratio of 49.64 dB was measured.

• 전자통신동향분석
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• 제39권3호
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• pp.79-86
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• 2024

Digital twins are gaining attention and traction across various industries and societies owing to their potential for technological advancement, utilization, and service innovation. Digital twins involve creating a software system that mirrors a real-world entity, enabling them to interact and cooperate, therfore resembling interaction between a real-world entity and a digital twin. By recognizing the importance of this technology, international standardization efforts for digital twins are actively underway toward enhancing its application across various industrial sectors. We aims to provide an overview of the current status and future prospects of digital twin standardization, focusing on the ISO/TC 184/SC 4 and ISO/IEC JTC 1/SC 41 efforts.

• 박물관보존과학
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• 제29권
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• pp.99-110
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• 2023

석조문화유산으로부터 결손된 석재편은 비교적 무겁고 부피가 커 직접 맞춰보고 원위치를 찾는 데 한계가 있으며, 수작업 시 이차적 물리적 손상이 발생할 가능성이 있다. 따라서 이 연구에서는 72점의 석재편이 함께 발굴된 예산 화전리 석조사면불상을 대상으로 디지털 복원을 통해 결손부와 석재편의 형상학적 관련성을 파악하고, 전시활용을 위해 3차원 프린팅 복제모형을 제작하였다. 디지털 복원을 위해 가상 공간에서 3차원 스캐닝 모델의 좌표를 정렬한 후 형상 유사도가 존재하는 석재편을 선정하였다. 또한 이 석재편을 3차원 프린터로 출력하여 결손부와 물리적인 접합 여부를 확인하였고, 이렇게 하여 총 7개소 9점의 석재편의 원위치를 파악하였다. 이러한 연구성과를 전시에 활용하기 위해 3차원 프린팅으로 석조사면불상의 1:1 복제모형을 제작하였고, 원위치가 파악된 석재편들 역시 복원되었다. 이번 연구에 사용된 디지털 기술은 직접적 수작업 방식의 한계를 보완하였을 뿐 아니라 유사 문화유산의 기록화, 복원, 복제 분야에 확대적용 가능성을 제안했다는 데 큰 의의가 있는 것으로 판단된다.

• 보존과학회지
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• 제32권1호
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• pp.51-61
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• 2016

어진御眞은 왕의 초상화로 조선시대에는 국조인 태조를 비롯하여 다수의 어진이 제작되어 영흥 준원전, 전주 경기전 등 여러 진전眞殿에 봉안奉安되었다. 이러한 어진은 이모移摸 과정을 통해 전해지고 있으며, 훼손된 어진의 경우 모사模寫 과정을 토대로 신본新本을 제작하였다. 근래에는 어진에 대한 다양한 학술적인 가치와 국민적인 관심 증대로 인하여 이모 작업이 활발하게 진행되고 있다. 국립고궁박물관에서는 다수의 어진을 보유하고 있는데, 소장본중 대부분이 한국전쟁 중 화재로 인해 손상된 상태로, 이모본 제작 과정에 필요한 초본 제작을 위해서는 범본範本이 되는 어진의 훼손된 부분에 관한 복원이 필요하다. 이 논문에서는 다분할 촬영 기법 및 이미지 분석 등의 디지털 이미징 기술을 활용하여, 국립고궁박물관 소장 태조어진의 훼손된 부분을 복원하는 과정과 이를 통해 밝혀진 태조어진 유물들의 용안의 차이를 중심으로 각 유물의 관계에 대해 연구한 것이다.

• 한국실내디자인학회논문집
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• 제18권3호
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• pp.66-73
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• 2009

In the digital age, as it is ambiguous to distinguish between the original and a replica, the order of reproduction which is more realistic than the reality is becoming a new cultural order. Before the period when digital paradigm dominates, always the reality has been an object to be copied. But, today is an age of Simulacre where code of digital technology dominates. Such a phenomenon is shown in the construction space without exception Gilles Deleuze who was a representative philosopher of the post-structuralism depicted the concept of Simulacre as an instant 'event' passing by without change in an object or substance. As the result of analyzing what kinds of feature for the concept of event is expressed in the digital space, a diagram itself could be a design process, the digital space with correlation was able to be created through the change in the meaning according to the changing image and my body which was the leading part to form primary space. In such a meaning, this study pays attention to Deleuze's 'Event(Simulacre)' concept. At this transitional period when a new concept of digital space is about to take root, the modern philosophers' theories and the discussions about spatial relativity should be continually studied, along with the development of spacial theories for the modem construction.

• The Journal of Advanced Prosthodontics
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• 제9권1호
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• pp.1-13
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• 2017

PURPOSE. The purpose of this study was to compare the fit of cast gold crowns fabricated from the conventional and the digital impression technique. MATERIALS AND METHODS. Artificial tooth in a master model and abutment teeth in ten patients were restored with cast gold crowns fabricated from the digital and the conventional impression technique. The forty silicone replicas were cut in three sections; each section was evaluated in nine points. The measurement was carried out by using a measuring microscope and I-Soultion. Data from the silicone replica were analyzed and all tests were performed with ${\alpha}$-level of 0.05. RESULTS. 1. The average gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. 2. In marginal and internal axial gap of cast gold crowns, no statistical differences were found between the two impression techniques. 3. The internal occlusal gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. CONCLUSION. Both prostheses presented clinically acceptable results with comparing the fit. The prostheses fabricated from the digital impression technique showed more gaps, in respect of occlusal surface.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.204-206
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• 2022

스마트 팩토리(Smart Factory) 고도화의 핵심으로 평가되는 디지털 트윈(Digital Twin)은 현실 세계의 자산과 동일한 속성 및 기능을 가지는 디지털 복제본을 가상의 세계에 구현하는 기술이다. 디지털 트윈 기술이 적용된 스마트팩토리는 생산공정의 실시간 모니터링, 생산공정 시뮬레이션, 생산설비 예지보전 등의 서비스를 지원할 수 있어 생산비용 절감 및 생산성 향상에 기여할 것으로 기대된다. AAS(Asset Administration Shell)는 디지털 트윈을 구현하기 위한 필수 기술로, 현실의 물리적 자산을 디지털로 표현하는 방법을 제공한다. 본 논문에서는 스마트팩토리 내 생산설비를 자산으로 간주하여, 운용 중인 실시간 CNC(Computer Numerical Control) 모니터링 시스템에서 활용할 제조 데이터 수집을 위한 AAS를 설계하였다.