• 대한치과교정학회지
• /
• 제53권2호
• /
• pp.77-88
• /
• 2023

Objective: To develop a method for generating three-dimensional (3D) digital models of the periodontal ligament (PDL) using 3D cone-beam computed tomography (CBCT) reconstruction and to evaluate the accuracy and agreement of the 3D PDL models in the measurement of periodontal bone loss. Methods: CBCT data collected from four patients with skeletal Class III malocclusion prior to periodontal surgery were reconstructed at three voxel sizes (0.2 mm, 0.25 mm, and 0.3 mm), and 3D tooth and alveolar bone models were generated to obtain digital PDL models for the maxillary and mandibular anterior teeth. Linear measurements of the alveolar bone crest obtained during periodontal surgery were compared with the digital measurements for assessment of the accuracy of the digital models. The agreement and reliability of the digital PDL models were analyzed using intra- and interexaminer correlation coefficients and Bland-Altman plots. Results: Digital models of the maxillary and mandibular anterior teeth, PDL, and alveolar bone of the four patients were successfully established. Relative to the intraoperative measurements, linear measurements obtained from the 3D digital models were accurate, and there were no significant differences among different voxel sizes at different sites. High diagnostic coincidence rates were found for the maxillary anterior teeth. The digital models showed high intra- and interexaminer agreement. Conclusions: Digital PDL models generated by 3D CBCT reconstruction can provide accurate and useful information regarding the alveolar crest morphology and facilitate reproducible measurements. This could assist clinicians in the evaluation of periodontal prognosis and establishment of an appropriate orthodontic treatment plan.

• 대한치과교정학회지
• /
• 제46권1호
• /
• pp.13-19
• /
• 2016

Objective: The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. Methods: CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Results: Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were $0.41{\pm}0.305%$ and $0.45{\pm}0.456%$, respectively; for anterior Bolton ratios, $0.59{\pm}0.520%$ and $1.01{\pm}0.780%$, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Conclusions: Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis.

• 한국BIM학회 논문집
• /
• 제9권4호
• /
• pp.41-50
• /
• 2019

Digital models for a cable-stayed bridge are defined considering data-driven engineering from design to construction. Algorithms for digital object generation of each component of the cable-stayed bridge were developed. Using these algorithms, Level-3 BIM practices can be realized from design stages. Based on previous practices, digital object library can be accumulated. Basic digital models are modified according to given design conditions by a designer. Once design models are planned, various applications using the models are linked the models such as estimation, drawings and mechanical properties. Federated bridge models are delivered to construction stages. In construction stage, the models can be efficiently revised according to the changed situations during construction phases. In this paper, measured coordinates are imported to the model generation algorithms and revised models are obtained. Augmented reality devices and their applications are proposed. AR simulations in construction site and in office condition are tested. From this pilot test of digital models, it can be said that Level-3 BIM practices can be realized by using in-house modeling algorithms according to different purposes.

• 한국경영정보학회:학술대회논문집
• /
• 한국경영정보학회 2007년도 International Conference
• /
• pp.646-651
• /
• 2007

Secure digital payment is critical in the successful shaping of global digital business. Digital payments are increasingly being used as a substitute to traditional payments, contributing markedly to the efficiency of the economy. The focus of every digital business transaction is to minimize risks arising from transactions. It is essential to ensure the security of digital payment whether used in internal networks or over wireless Internet. This paper analyses secure digital payment methods from the viewpoint of systemic security and transaction security. According to comparative analysis of digital payment models, this paper proposes a comparative analysis framework to investigate and evaluate secure digital payment. In conclusion, the comparative analysis framework, comparison of digital payment models and mobile payment models proposes a useful academic and practical foundation to enhance the understanding of secure digital payment methods. It also provides academic background and practical guidelines for the development of secure digital payment systems.

• Journal of Korean Dental Science
• /
• 제15권2호
• /
• pp.132-140
• /
• 2022

Purpose: Dental diagnostic records derived from study models are a popular method of obtaining reliable and vital information. Conventional plaster models are the most common method, however, they are being gradually replaced by digital impressions as technology advances. Moreover, three-dimensional dental models are becoming increasingly common in dental offices, and various methods are available for obtaining them. This study aimed to evaluate the accuracy of the measurement of dental digital models by comparing them with conventional plaster and to determine their clinical validity. Materials and Methods: The study was conducted on 16 patients' maxillary and mandibular dental models. Tooth size (TS), intercanine width (ICW), intermolar width (IMW), and Bolton analysis were taken by using a digital caliper on a plaster model obtained from each patient, while intraoral scans were manually measured using two digital analysis software. A one-way analysis of variance test was used to compare the dental measurements of the three methods. Result: No significant differences were reported between the TS, the ICW and IMW, and the Bolton analysis through the conventional and two digital groups. Conclusion: Measurements of TS, arch width, and Bolton analysis produced from digital models have shown acceptable clinical validity. No significant differences were observed between the three dental measurement techniques.

• Smart Structures and Systems
• /
• 제30권1호
• /
• pp.35-47
• /
• 2022

Data-driven engineering is crucial for information delivery between design, fabrication, assembly, and maintenance of prefabricated structures. Design for manufacturing and assembly (DfMA) is a critical methodology for prefabricated bridge structures. In this study, a novel concept of digital engineering model that combined existing knowledge of DfMA with object-oriented parametric modeling technologies was developed. Three-dimensional (3D) geometry models and their data models for each phase of a construction project were defined for information delivery. Digital design models were used for conceptual design, including aesthetic consideration and possible variation during fabrication and assembly. The seismic performance of a bridge pier was evaluated by linking the design parameters to the calculated moment-curvature curves. Control parameters were selected to consider the tolerance control and revision of the digital models. Digitalized fabrication of the prefabricated members was realized using the digital fabrication model with G-code for a concrete printer or a robot. The fabrication error was evaluated and the design digital models were updated. The revised fabrication models were used in the preassembly simulation to guarantee constructability. For the maintenance of the bridge, the as-built information was defined for the prefabricated bridge piers. The results of this process revealed that data-driven information delivery is crucial for lifecycle management of prefabricated bridge piers.

• 치위생과학회지
• /
• 제14권1호
• /
• pp.15-21
• /
• 2014

본 연구에서는 구강으로부터 채득된 인상체를 스캐닝하여 디지털 모형을 제작하였을 때 제작된 디지털 모형의 체적 안정성을 평가하고자 하였다. 그리하여 환자의 구강을 가정한 상악 모형을 본 모형으로 채택하였다. 본 모형과 동일한 증례의 연구 모형을 치과용 석고를 이용하여 총 20개의 석고 모형을 제작하였다. 제작된 연구 모형 20개를 치과용 기성 트레이와 두 종류의 치과용 인상재를 이용하여 20개 연구 모형을 대상으로 20개의 인상을 채득하였다. 채득된 20개의 인상체를 치과용 스캐너로 스캐닝하는 방식으로 디지털 모형으로 변환하였다. 체적 안정성을 평가하기 위하여 6개의 대표 지점을 선정한 뒤 디지털 모형과 함께 디지털 모형의 근간인 석고 모형을 계측하였다. 그 결과 계측된 모든 부위에서 디지털 모형이 석고 모형보다 체적이 작은 것으로 조사되었고, 이는 통계적으로 유의하였다(p<0.05). 이러한 결과들로 추론하여 보았을 때 환자의 구강으로부터 채득된 인상체를 스캐닝하여 제작한 디지털 모형의 체적은 환자의 구강보다 작다는 것을 알 수 있었다. 그러나 이 차이는 미비한 것으로 여러 선행 연구 결과들을 근거로 하였을 때 임상적으로 허용이 가능한 것으로 생각된다.

• 한국콘텐츠학회논문지
• /
• 제12권10호
• /
• pp.357-364
• /
• 2012

치과용 스캐너를 기반으로 하는 디지털 모형은 기존의 전통적인 석고모형을 대체할 만큼 발전되고 있다. 본 연구의 목적은 디지털모형의 정확도와 신뢰도를 평가하고자 하였다. 상악의 전악모형을 주 모형으로 설정하여 주 모형으로부터 석고모형을 제작하였고(N=10), 치과용 백색광 스캐너를 이용하여 10개의 디지털모형 데이터를 채득하였다. 제작된 두 실험군(석고모형, 디지털모형)을 1명의 검사자가 2회에 걸쳐서 6곳의 계측지점을 측정하였다. 짝 표본 t-검정과 급내 상관계수을 이용하여 통계적인 분석을 하였다. 실험결과 측정값의 검사자 내 신뢰도는 급내 상관계수 결과 두 실험군 0.75에서 0.87의 범위를 보였다. 석고모형과 디지털 모형의 평균 오차값은 0.11mm에서 0.23mm의 범위를 나타내었고, 모든 계측지점에서 통계적으로 유의한 차이를 보였다(P<0.05). 본 실험결과 모든 계측지점에서 적정수준의 정확성은 확보되지 않았으나, 선행연구에 비추어 볼 때 임상적인 효용성은 검증되었다. 추가적으로 임상적인 사례를 통해 평가되어야 할 것으로 사료된다.

• 한국BIM학회 논문집
• /
• 제12권1호
• /
• pp.10-22
• /
• 2022

Prefabricated bridges require strict management of tolerance during fabrication and assembly. In this paper, digital engineering models for prefabricated bridge components such as deck, girder, pier, abutment are suggested to support information delivery through the life-cycle of the bridge. Rule-based modeling is used to define geometry of the members considering variable dimensions due to fabrication and assembly error. DfMA(design for manufacturing and assembly) provides the rules for ease of fabrication and assembly. The digital engineering model consists of geometry, constraints and corresponding parameters for each phase. Alignment and control points are defined to manage tolerances of the prefabricated bridge during fabrication and assembly. Quality control by digital measurement of dimensions was also considered in the model definition. A pilot bridge was defined virtually to validate the suggested digital engineering models. The digital engineering models for DfMA showed excellent potential to realize prefabricated bridges.

• 한국BIM학회 논문집
• /
• 제9권2호
• /
• pp.29-44
• /
• 2019

This paper is to explore examples of complementary use of digital and physical models. The reason for this is to suggest a method for commercializing architectural design considering high technology. These cases are the practical and educational environment in which design processes based on digital computation technology are performed. Also, in this environment, analog design media (eg, physical models) still being used in the design process using digital computing. Indeed, in this environment, designers are exploiting digital and physical models to address the types of risks that can be discovered when designs are implemented and these risks. By analyzing these cases, we define the roles of digital and physical models to visualize and resolve risks. This paper focuses on one of method as "prototyping", which is used in the field of machinery and is a difficult method to carry out in the conventional design process. In particular, designers look for benefits that encourage designers in utilizing current digital computation technologies (eg, parametric design, simulation, building information models, and digital fabrication). Among the roles of the physical model, roles that can not be replaced by the digital model are explored. It is clear that this case-based study has difficulty in generalizing the design method. However, it helps the designers of today's practical and educational environment to verify and design the actual details of construction and operation when applying and developing unfamiliar materials and methods in the field of architecture.