• 대한치과교정학회지
• /
• 제51권6호
• /
• pp.375-386
• /
• 2021

Objective: To evaluate the accuracy of a one-piece bracket jig system fabricated using computer-aided design and manufacturing (CAD/CAM) by employing three-dimensional (3D) digital superimposition. Methods: This in vitro study included 226 anterior teeth selected from 20 patients undergoing orthodontic treatment. Bracket position errors from each of the 40 arches were analyzed quantitatively via 3D digital superimposition (best-fit algorithm) of the virtual bracket and actual bracket after indirect bonding, after accounting for possible variables that may affect accuracy, such as crowding and presence of the resin base. Results: The device could transfer the bracket accurately to the desired position of the patient's dentition within a clinically acceptable range of ± 0.05 mm and 2.0° for linear and angular measurements, respectively. The average linear measurements ranged from 0.029 to 0.101 mm. Among the angular measurements, rotation values showed the least deviation and ranged from 0.396° to 0.623°. Directional bias was pronounced in the vertical direction, and many brackets were bonded toward the occlusal surface. However, no statistical difference was found for the three angular measurement values (torque, angulation, and rotation) in any of the groups classified according to crowding. When the teeth were moderately crowded, the mesio-distal, bucco-lingual, and rotation measurement values were affected by the presence of the resin base. Conclusions: The characteristics of the CAD/CAM one-piece jig system were demonstrated according to the influencing factors, and the transfer accuracy was verified to be within a clinically acceptable level for the indirect bracket bonding of anterior teeth.

• The Journal of Advanced Prosthodontics
• /
• 제13권6호
• /
• pp.373-384
• /
• 2021

PURPOSE. This study aimed to compare the marginal and internal fit of 3-unit monolithic zirconia restorations that were designed by using the data obtained with the aid of intraoral and laboratory scanners. MATERIALS AND METHODS. For the fabrication of 3-unit monolithic zirconia restorations using impressions taken from the maxillary master cast, plaster cast was created and scanned in laboratory scanners (InEos X5 and D900L). The main cast was also scanned with different intraoral scanners (Omnicam [OMNI], Primescan [PS], Trios 3 [T3], Trios 4 [T4]) (n = 12 per group). Zirconia fixed partial dentures were virtually designed, produced from presintered block, and subsequently sintered. Marginal and internal discrepancy values (in ㎛) were measured by using silicone replica method under stereomicroscope. Data were statistically analyzed by using 1-way ANOVA and Kruskal Wallis tests (P<.05). RESULTS. In terms of marginal adaptation, the measurements on the canine tooth indicated better performance with intraoral scanners than those in laboratory scanners, but there was no difference among intraoral scanners (P<.05). In the premolar tooth, PS had the lowest marginal (86.9 ± 19.2 ㎛) and axial (92.4 ± 14.8 ㎛), and T4 had the lowest axio-occlusal (89.4 ± 15.6 ㎛) and occlusal (89.1 ± 13.9 ㎛) discrepancy value. In both canine and premolar teeth, the D900L was found to be the most marginally and internally inconsistent scanner. CONCLUSION. Within the limits of the study, marginal and internal discrepancy values were generally lower in intraoral scanners than in laboratory scanners. Marginal discrepancy values of scanners were clinically acceptable (< 120 ㎛), except D900L.

• 국제학술발표논문집
• /
• The 9th International Conference on Construction Engineering and Project Management
• /
• pp.1250-1251
• /
• 2022

Measuring management is an important part of preventing the collapse of retaining walls in advance by evaluating their stability with a variety of measuring instruments. The current work of measuring management requires considerable human and material resources since measurement companies need to install measuring instruments at various places on the retaining wall and visit the construction site to collect measurement data and evaluate the stability of the retaining wall. It was investigated that the applicability of the current work of measuring management is poor at small and medium-sized urban construction sites(excavation depth<10m) where measuring management is not essential. Therefore, the purpose of this study is to develop a laser sensor-based hardware to support the wall displacement measurements and their control software applicable to small and medium-sized urban construction sites. The 2D lidar sensor, which is more economical than a 3D laser scanner, is applied as element technology. Additionally, the hardware is mounted on the corner strut of the retaining wall, and it collects point cloud data of the retaining wall by rotating the 2D lidar sensor 360° through a servo motor. Point cloud data collected from the hardware can be transmitted through Wi-Fi to a displacement analysis device (notebook). The hardware control software is designed to control the 2D lidar sensor and servo motor in the displacement analysis device by remote access. The process of analyzing the displacement of a retaining wall using the developed hardware and software is as follows: the construction site manager uses the displacement analysis device to 1)collect the initial point cloud data, and after a certain period 2)comparative point cloud data is collected, and 3)the distance between the initial point and comparison point cloud data is calculated in order. As a result of performing an indoor experiment, the analyses show that a displacement of approximately 15 mm can be identified. In the future, the integrated system of the hardware designed here, and the displacement analysis software to be developed can be applied to small and medium-sized urban construction sites through several field experiments. Therefore, effective management of the displacement of the retaining wall is possible in comparison with the current measuring management work in terms of ease of installation, dismantlement, displacement measurement, and economic feasibility.

• 한국의류학회지
• /
• 제33권7호
• /
• pp.1109-1120
• /
• 2009

This study develops a fitted torso type basic pattern for men by utilizing 3D body scan data. Recent fashion trends are reflected in the development of the pattern. The subjects were 15 men in their 20's, who wear size 95 (M size). Body scan data was obtained through a 3D whole body scanner (WB4, Cyberware, USA), and a body surface development figure for developing male fitted torso type basic pattern was attained through the use of Rapid Form 2006 as well as Auto CAD 2006 programs. The results are as follows: A body surface development figure through body surface segment method showed high exactitude in an error range of 100$\pm$1%. In addition, it occurred in an error range of 100:1:3% because of the hard scanning conditions in the incline of the shoulder and armpit areas. However, the body surface development figure as well as the direct measurement results can be used as basic data for the given patternmaking since the error range falls into 100$\pm$3%. Dart amounts obtained from the average cross section were center back 2.2cm (24.3%), back armpit point 3.8cm (41.8%), front armpit point 3.0cm (33.9%). As shown the jacket pattern, the biggest dart amount was portioned out at the back armpit point. The drafting equations for the development pattern acquired are as follows; Full width=C/2+5cm, back length=height/4-1cm, armhole depth=(C/10+12cm)+3cm, back width=2C/10+2cm, front width=2C/10. The development pattern was a fitted torso basic pattern that was composed of 3 pieces, so it would be very useful in developing shirt or jacket patterns. According to the results of the evaluation of the developed pattern appearance, it obtained higher scores of over 3.5 points in almost items, meaning that the developed pattern is appropriate for a male fitted torso type basic pattern. It suggests a possibility of patternmaking from a body surface development figure in 2-D to prototype.

• 한국의류산업학회지
• /
• 제11권5호
• /
• pp.788-798
• /
• 2009

This study aims to develop a highly reproducible, optimal frame design algorithm using variations in the curvature of armscye circumference, which will provide the basics for remodeling the 3D human body shape with the concept of reverse design used to develop total contents for the apparel industry. 1. The results of the experiment proved that ratio value was significantly efficient than absolute value of curvature variation to extract feature points in the armscye circumference 2. For the shoulder(1st and 2nd quadrant) and front armhole(3rd quadrant) parts of the armscye circumference, frame remodeling with the positive point of inflection led to the completion of a highly reproducible frame. 3. Similarly, even for the rear armhole part(4th quadrant) in the armscye circumference, it was found that frame remodeling using the positive maximum point of inflection resulted in highly reproducible body shape with the maximum point of inflection situated within the range of split angles $305^{\circ}{\sim}330^{\circ}$, while frame remodeling using simultaneously the two largest points of inflection including maximum point of inflection led to highly reproducible body shape with the maximum point of inflection out of the range $305^{\circ}{\sim}330^{\circ}$. 4. Based upon the optimal frame design algorithm developed in this study, section-specific feature points in the armscye circumference were extracted depending on the rate of curvature variation and remodeling with spline curves was conducted. The results indicate a remarkably high reproducibility(98.6%) and suggest that the algorithm developed in this study is suitable for human body modeling.

• 대한토목학회논문집
• /
• 제40권2호
• /
• pp.191-195
• /
• 2020

부식된 관로의 상태를 평가하기 위해서 수행하는 직접평가 중 인장 실험을 수행하였다. 부식된 관로에서 절삭 가공하여 인장 시편을 취득하면, 관로의 관경에 따라 곡률이 변화하고 실제 평평한 시편의 거동과 달라질 수 있어 이를 확인하기 위한 연구를 수행하였다. 시편의 전 영역이 평평한 경우, 곡률이 있는 경우 그리고 시편에 곡률이 존재하면서 그립 부분만 평평하게 가공한 경우에 대해서 부식이 없는 경우와 부식이 존재하는 경우(두께 대비 25, 50 %의 단일 부식)로 나누어 해석을 진행하였다. 부식이 존재하게 되면 응력 집중이 단면 감소부에서 확실하게 나타나 그립의 가공 여부가 시편의 인장거동에 영향을 거의 주지 않는다는 것을 해석을 통해 확인하였다. 또한 실제 부식이 있는 시편에 대하여 3D 스캔을 진행하고 이를 반영한 해석 모델을 만들어 실험 결과와 비교 분석하였다.

• 대한치과보철학회지
• /
• 제59권1호
• /
• pp.126-133
• /
• 2021

여러 연구에서 임플란트 지지 보철물의 수직 침하에 대해 보고되고 있지만, 구강내 임플란트 지지보철물의 기능 시 수직침하 양상에 대해서는 알려진 바 없다. 본 증례에서는 2명의 환자에서 구치부 단일 치아 임플란트 지지 보철물의 3차원적인 변화를 평가하였다. 내부연결형 임플란트를 식립하였으며 통상적인 방법으로 Screw-Cement Retained Prosthesis(SCRP) 형태의 보철물을 제작해 장착하였다. 구강스캐너(Cerec Omnicam, Dentsply Sirona, USA)를 이용해 보철물 장착 시, 장착 1주, 1개월, 1년 후 구강 스캔을 시행하였으며 디지털 분석 프로그램(Geomagic Control X, 3D systems, USA)을 이용해 기간에 따른 위치 변화를 3차원적으로 평가하였다. 인접 치아를 기준으로 보철물 장착 후 임상적인 위치 변화가 나타났으며 변화량은 시간이 지남에 따라 증가하였다.

• 소성∙가공
• /
• 제33권2호
• /
• pp.103-111
• /
• 2024

With the increasing global interest in carbon neutrality, the automotive industry is also transitioning to the production of eco-friendly cars, specifically electric vehicles. In order to achieve comparable driving distances to internal combustion engine vehicles, the application of high-capacity battery packs has led to an increase in vehicle weight. To achieve light-weighting and durability requirements of automotive components simultaneously, there is a demand for research on the application of Ultra-High Strength Steel (UHSS). However, when manufacturing chassis components using UHSS, there are challenges related to fracture defects due to lower elongation compared to regular steel sheets, as well as spring-back issues caused by high tensile strength. In this study, a simulated specimen that is not affected by the property changes of four materials was designed to improve formability of the rear cross member, which is the most challenging automotive chassis component. The influence and correlation of material-specific variables were analyzed through finite element analysis (FEA) for each material with tensile strength of 440, 590, 780, and 980 MPa grades, resulting in the development of a predictive equation. To validate the equation, the simulated specimens of 980 MPa grade were produced from the test molds. Then the reliability of the FEA and predictive equation was verified with measured specimen data using a 3D scanner. The results of this study can be proposed to improve the formability of UHSS chassis components in future researches.

• 한국의류학회지
• /
• 제30권11호
• /
• pp.1598-1607
• /
• 2006

The purpose of this study was to analyze the proportion of gathered skirts using a three-dimensional measurement system. And in this experiment, we have attempted to accumulate three-dimensional data of wearing model and find out adequate methods for analyzing shape of clothes. The experimental design consists of two factorial designs. We established three different kinds of fabrics, ratio of gathers. The measurement tool for three-dimensional model was whole body 3D scanner(Exima-WBS2H). Analysis program used in experiment is RapidForm 2004 PP1 and Pattern Design 2000. Data analysis utilizes SPSS WIN 10.0 Package. As the results show, there were different effect of gather and proportion of shapes among the measurements of width, thickness and areas made by different lines of vision in cross-sectional silhouette. And there were difference shapes of section area at each part of gathered skirts between vertical-outline silhouette and vortical-plane silhouette made by gathering conditions. And also the cross-sectional silhouettes and vertical silhouettes were related to shape of clothes.

• 한국의류산업학회지
• /
• 제6권4호
• /
• pp.485-491
• /
• 2004

The purpose of this study is to analyze the wearing fitness of middle aged women's jacket with non-Stretchable Fabric and stretchable fabric. We surveyed the size of jackets and process of pattern making with stretchable fabric in companies which produce the clothing mainly for middle aged women. Based upon the result of process of pattern making, two kind of experimental jacket with non-stretchable and stretchable fabric were made. We measured space length between body and garment using 3D scanner and analyzed the clothing pressure 7 parts of body with 3 kinds of arm raising. The result were as follows : 1. Most parts of space length except bust were higher in non-stretchable jacket than in stretchable jacket. 2. Clothing pressure showed greater value with non-stretchable fabric jacket than with stretchable fabric jacket. Clothing pressure in upper arm point areas increased as the angle of the arm raising increased. Therefore, the sleeve width and armhole depth should he considered when the amount of wearing ease were reduced in jacket with stretchable fabric.