• Journal of Dental Rehabilitation and Applied Science
• /
• 제40권1호
• /
• pp.24-30
• /
• 2024

Complicated crown fractures of maxillary anterior teeth caused by trauma in adolescence can cause functional and aesthetic problems. For crown fractures with pulp exposure, various restorative methods can be considered depending on the amount of remaining tooth structure. Direct resin restorations are the most traditional and effective method, but they are likely to discolor and break over time. Fixed prosthesis have a high possibility of re-restoration due to marginal disharmony due to tooth movement during the growth period, and restorations using post which are mainly performed for extensive crown fractures increase the risk of root perforation and root fracture. However, endocrown is an integrated structure that gains retention force from the pulp space, enabling effective reconstruction from a biomechanical perspective and providing advantages in restoring function and aesthetics. Therefore, endocrown can be considered as a restoration method for complicated crown fractures caused by trauma in adolescence.

• The Journal of the Convergence on Culture Technology
• /
• 제10권1호
• /
• pp.459-464
• /
• 2024

The purpose of this study is to design a toilet lifting seat to prevent falls accidents in the elderly while using the toilet. Prior to design, laws and national standards related to restroom use were investigated and the available space for the assistive devices to be installed was determined. In additions, considering the body size and operating range of the elderly, the optimal final position of the toilet seat is set so that users can use it more safely and conveniently without external help. Moreover, in order to provide an effective standing assistance function, a complex 4-bar link structure was applied to enable simultaneous seat elevation and angle adjustment when operating the device, and the appropriate link shape and dimensions were determined using a linkage program and UG NX. FEA analysis using ANSYS Workbench is performed to ensure the robustness of the stretched linkage and the feasibility of the lifting seat is verified through fabrication.

• Journal of the Ergonomics Society of Korea
• /
• 제23권3호
• /
• pp.25-38
• /
• 2004

Selection of a key dimension (s) by considering the characteristics of hand dimensions is needed to design gloves and construct a sound sizing system for gloves The present study identified key dimensions of glove design by analyzing the relationships between hand dimensions and demonstrated the construction process of a glove sizing system. By conducting correlation and regression analyses on 70 hand dimensions including 3 key dimension candidates (hand length; hand circumference; hand breadth) with the 1988 US Army data, hand length and hand circumference were selected as key dimensions for glove design. Glove sizing systems were constructed for males and females by applying the selected key dimensions, 0.5 inch of sizing intervals, and 2％ of presence rate criterion to the US Army data. This study suggests that glove sizing systems for males and females be very different from each other and a glove sizing system for males include more sizes than that for females.

• Journal of the Korean Society for Precision Engineering
• /
• 제31권1호
• /
• pp.9-13
• /
• 2014

The molding process can be divided into five separate steps: plastification, injection, holding, cooling, and finally ejection. In the plastic injection molding, the effect factor such as mold temperature, injection speed, packing pressure and inhomogeneous cooling under packing process affects both the article dimension and physical characteristics. Especially, the packing pressure is the most critical factor to affect molded articles quality among the packing parameters. In this paper, the CAE simulation considering the molding condition is performed to predict the faulty cause which appears in the packing process between cavities of injection molding machine. From the results of CAE simulation, the packing phenomena according to the product form and the gate position was investigated to improve the article quality and minimize the various molding defects. The effect of packing pressure and gate number on the injection molding was discussed.

• IE interfaces
• /
• 제24권2호
• /
• pp.105-111
• /
• 2011

Measurement protocols for hand anthropometry have been studied for ergonomic product design. The present study developed a 3D semi-automatic measurement protocol (3D-SAMP) which semi-automatically measures various hand dimensions using a 3D scanner. The 3D-SAMP was compared with the conventional direct measurement method (DMM) to examine its effectiveness. The 3D-SAMP consists of (1) fabricating a plaster cast of the hand, (2) placing landmarks on the plaster hand, (3) scanning the plaster hand with a 3D scanner, (4) identifying automatically the positions of the landmarks on the digital hand, and (5) extracting automatically hand anthropometric measurements (lengths, widths, thicknesses, and circumferences). An evaluation experiment conducted in the study found the 3D-SAMP preferred to the DMM in terms of reliability (the number of dimensions exceeding the variability criteria SD=2 mm and CV=5% : 3D-SAMP =2 and DMM=24) and ease of measurement (3D-SAMP=5.2 and DMM=4.3 out of 7). The 3D-SAMP can be applied to ergonomic design of a hand-held product.

• The Journal of the Korean dental association
• /
• 제56권6호
• /
• pp.314-322
• /
• 2018

Among developmental anomalies of tooth shape, fusion and gemination are comparatively common. Developed with different etiologies, both fusion and gemination show similar clinical features. Therefore, many clinicians have difficulty diagnosing those morpho-anatomic anomalies. The purpose of this study is to report malformed right maxillary first molar in a 20-year-old female. With the aid of computed tomography (CT), the tooth was diagnosed as fusion with supernumerary tooth and dental caries lesion was detected. After performing direct pulp capping, the tooth was permanently restored with microhybrid composite resin using direct method to alter union groove into smooth surface for improving oral hygiene management. Until 6 months of follow-up visits, patient's chief complaint was resolved and tooth is still vital. In conclusion, identifying exact anatomy, conservative treatment and improving oral hygiene are essential in managing unusual morphologic anomalies of tooth.

• Journal of Korean Institute of Industrial Engineers
• /
• 제36권3호
• /
• pp.146-153
• /
• 2010

The purposes of this are (1) to present representative five hand dimensions by measurement year, (2) to investigate hand characteristics based on relative ratios of varying hand dimensions and (3) to compare Korean hand dimensions to other countries' data. Comparing to those of 1979, statures of 2004 increased by 3.0~3.5%, while males' hand dimensions of hand length, medius finger length, hand circumference, hand breadth and hand thickness decreased by 2.0~5.0%. Ratios of hand dimensions to those of medius finger were not significantly different depending upon age group and gender, but were significantly different depending upon races of Korean and American. Hand lengths of Koreans were shorter by about 4.0% than those of Japanese irrespective of gender, while the other compared dimensions for Koreans were larger than those of Japanese. Hand dimensions used in this study of Koreans were generally smaller that those of Americans. It is recommended from this study that when designing hand relevant things including glove, computer keyboard, smart phone key pad, etc., the different hand characteristics found in this study be fully reflected to develop competitive products.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
• /
• pp.835-837
• /
• 2017

In this paper, manufacturing processes of cylindrical composite lattice structures using filament winding method was described. Cylindrical composite lattice structures were manufactured in accordance with four major steps. Silicon mold of lattice shape was installed on mandrel and then continuous fiber was wound on silicon mold. After winding process, in order to ensure the same thickness for all regions, compression process was done for its intersection parts. Finally, the composite lattice structure was demoulded after curing in oven. It was found that the manufactured cylindrical composites lattice structure had 2.4% of dimensional error compared to the design requirements.

• Journal of the Korean Society of Industry Convergence
• /
• 제25권3호
• /
• pp.357-363
• /
• 2022

In this study, in order to develop an non-slip metal grating, the stability of the grating according to the span of the grating and the gap and height of the bearing bar was evaluated. The optimal shape design of the grating was performed using the results of determining the stability of the grating. The purpose of this study is to determine the stability according to the spacing and height of the bearing bar by applying the design pressure at the design stage to develop the anti-skid grating, and to design the optimal shape for cost reduction. In the optimal design, the target variable was set as the mass, and the optimal design of the grating was performed based on about 20%. Regardless of the height of the bearing bar of the grating, the stress and deformation of the span and the grating showed a proportional tendency to each other, and it was found that the stress decreased as the height of the bearing bar increased. Based on the structural analysis results, an optimal design was performed using mass as the objective variable, and the existing 2mm thickness was changed to 1.6mm, reducing the mass by about 19%. The stress increased by about 4.4% compared to the maximum stress of the existing grating, but the minimum safety factor was 3.1, indicating that the optimally designed grating was stable.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 한국컴퓨터정보학회 2020년도 제61차 동계학술대회논문집 28권1호
• /
• pp.259-260
• /
• 2020

모바일 게임 시장 규모가 커짐에 따라 RPG, 보드게임 등 다양한 종류의 모바일 게임이 출시되고 있다. 그 중 보드게임의 경우 대부분이 과도한 과금 요소, 지나치게 운에 따라 승패가 결정되어 이에 불만을 가지는 사용자들이 많다. 본 논문에서는 기존 보드게임의 형식을 탈피해 새로운 보드게임 형식을 제공하고, 운적인 요소와 과금 요소를 최소화하여 전략을 통해 승패를 가르는 모바일 기반 게임 애플리케이션을 개발하였다. 또한 보드게임에 레이싱 요소를 결합함으로써 턴 방식이 아닌 실시간 방식으로 게임을 운영하고, 게임의 긴박감을 증가시켜 색다른 경험과 재미를 제공한다.