• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.27.1-27.9
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• 2020

Apical surgery for a mandibular molar is still challenging for many reasons. This report describes the applications of computer-guided cortical 'bone-window technique' using piezoelectric saws that prevented any nerve damage in performing endodontic microsurgery of a mandibular molar. A 49-year-old woman presented with gumboil on tooth #36 (previously endodontically treated tooth) and was diagnosed with chronic apical abscess. Periapical lesions were confirmed using cone-beam computed tomography (CBCT). Endodontic microsurgery for the mesial and distal roots of tooth #36 was planned. Following the transfer of data of the CBCT images and the scanned cast to an implant surgical planning program, data from both devices were merged. A surgical stent was designed, on the superimposed three-dimensional model, to guide the preparation of a cortical window on the buccal side of tooth #36. Endodontic microsurgery was performed with a printed surgical template. Minimal osteotomy was required and preservation of the buccal cortical plate rendered this endodontic surgery less traumatic. No postoperative complications such as mental nerve damage were reported. Window technique guided by a computer-aided design/computer-aided manufacture based surgical template can be considerably useful in endodontic microsurgery in complicated cases.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.82-89
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• 1995

The three-dimensional fluid motion through the intake port and cylinder of a single DOHC SI engine was investigated with a commercial computational fluid dynamics simulation program, STAR-CD. This domain includes the intake port, intake valves and combustion chamber. Steady induction port flows for various valve lifts have been simulated for an actual engine configuration. The geometry was obtained by direct interface with a three-dimensional CAD software for complicated port and valve shape. The computational grid was generated using the commercial preprocessor ICEM CFD/CAE. Detailed procedures were presented on the generation of the geometry and the block-structured mesh. A standard k-${\varepsilon}$ turbulent model was applied to consider the complexity of the geometry and the fluid motion. The global flow patterns and the distributions of various quantities, such as pressure, velocity magnitude around the valve seat etc., were examined. The computational results, such as mass flow rate, discharge coefficient etc., for various valve lifts were compard with the experimental results and the computational results were found in good agreement with the experiment.

• Journal of the Korean Society of Clothing and Textiles
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• v.43 no.2
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• pp.204-214
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• 2019

A CAD program has recently been introduced that can be directly developed into a three-dimensional human body shape and made into a pattern. It is possible to fabricate a bra that reflects the volume and surface area of the breast; however, it still needs to be verified. This study investigates the average size and shape of 20 big-breasted women and designs a brassiere pattern for women with large breasts using a 3D Flattening function of OptiTex PDS v15.6. In addition, the study verifies the reliability of the proposed method compared to a conventional brassiere pattern. The study results are as follows. First, the three dimensional measurement values were smaller than the direct measurement dimensions when the three dimension measurement dimensions of the subjects were compared with the direct measurement dimensions, the replica measurement dimensions and the three dimensional measurement dimensions. Second, the 3D flattening pattern reflects the actual shape, length, and area of the actual breast when comparing a brassiere pattern using a 3D shape and pattern reflecting the direct measurement.

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.947-956
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• 2018

This research has been conducted to design upright parts of hand-made vehicles with the purpose of reducing material and machining cost while ensuring structural safety. Aluminum knuckles were modelled with three parts in order to enhance design flexibility as well as to reduce CNC machining cost. A vehicle model was constructed in CAD program and simulated in ADAMS View in order to estimate joint forces developing during 20 degree step steering condition at 60km/h. The joint forces obtained in the vehicle dynamics simulation were used for the structural analysis in ANSYS and dimensions of knuckle parts were adjusted until the lowest safety factor reached 2.0. The weight of knuckle decreased by 50% compared to the previous version that was designed without the structural analysis. The overall manufacturing cost decreased by 33% due to the reduction in the material as well as the CNC machining effort.

• The Research Journal of the Costume Culture
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• v.31 no.2
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• pp.213-227
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• 2023

To analyze the status and needs of the small- and medium-sized garment manufacturing industry in Busan, this study comprised an online survey of companies and interviews with 14 representatives of the 98 companies. The results are as follows: Approximately 34.7% of the garment manufacturers were located in Geumjeong-gu, Busan. The most common type of work was the contracting factory type. Daily production output was between 100pcs and 300pcs. Production materials comprised 42.9% woven and 24.8% knitted fabrics. Main products were menswear, uniforms, womenswear, casual wear, sports and leisure wear, protective clothes, and children's clothing. The main clients were uniform companies, main factories, wholesale markets, online shopping malls and promotion companies, exporters, and department stores. As a result of a survey on industrial needs with company representatives, their satisfaction with company employees was 57.2%, and the most important factor when hiring employees was job-related competencies, among which the ability to understand the sewing process was the most necessary. In terms of computer software literacy, illustrations and pattern CAD/CAM are required. They thought industry-university cooperation is crucial for advantage for advantage research and product development, as it allows for the sharing knowledge, resources, and especially human resources. The greatest administrative issue were human resources and funding.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1059-1066
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• 2022

In 2020, it was estimated that more than 2.4 million households in South Korea are over 30 years old. That is, more than 40% of all houses in Korea are old and that they require proper rehabilitation. The two options to improve poor living conditions are reconstruction and remodeling. Compared to reconstruction, remodeling has advantages in terms of the construction period, cost, and environmental impact. As such, the current Korean regulations are more favorable for remodeling than reconstruction. Typically, several candidate floor plans are presented in the early stages of an apartment remodeling project. Extracting information about bearing walls and other structural elements from the multiple plans to compare those plans quantitatively is one of the essential tasks during the early stage of a project. To cope with this task, an automated data extraction method for walls and slabs from before and after remodeling plans is developed. Through the developed program, load-bearing walls, non-bearing walls, slabs, and weight changes after remodeling can be analyzed and visualized in a fast and automated manner.

• Land and Housing Review
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• v.8 no.1
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• pp.23-29
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• 2017

The BIM design is expected to expand to the domestic and overseas construction industries, depending on the effect of construction productivity and quality improvement. However, with the obligation of Public Procurement Service to design the BIM design, it includes a design error and the problem of utilization of 3D design by choosing a simple 2D to 3D remodelling method that can not be modelled in 3D modeling or use of the construction and maintenance phases. The results reviewed by BIM design results were largely underutilized and were not even performed with the verification of the error. In order to resolve this, one must develop the check system that secures the quality of BIM design and ensure that the reliability of BIM results are available. In this study, it is designed to develop a program that can automatically verify the design of the BIM design results such as violation of the rules of the BIM design, design flaws, and improve the usability of the BIM design. In particular, this programs were developed not only to identify programmes that were not commercially available, but also to validate drawings in low-light computer environments. The developed program(LH-BIM) store the information of attribute extracted from the Revit file(ArchiCAD, IFC file included) in the integrated DB. This provides the ability to freely lookup the features and properties of drawings delivered exclusively by the LH-BIM Program without using the Revit tools. By doing so, it was possible to resolve the difficulties of using traditional commercial programs and to ensure that they operate only with traditional PC performance. Further, the results of the various BIM software can be readily validated, which can be solved the conversion process error of IFC in the case of SMC. Additionally, the developed program has the ability to automatically check the error and design criteria of the drawings, as well as the ability to calculate the area estimation. These functions allow businesses to apply simple and easy tasks to operate tasks of BIM modelling. The developed system(LH-BIM) carried out a verification test by reviewing the review of the BIM Design model of the Korea Land & Housing Corporation. It is hoped that the verification system will not only be able to achieve the Quality of BIM design, but also contribute to the expansion of BIM and future construction BIM.

• The Journal of Advanced Prosthodontics
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• v.9 no.3
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• pp.176-181
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• 2017

PURPOSE. The purpose of this study was to evaluate the marginal and internal gaps of Ni-Cr and Co-Cr copings, fabricated using the dental ${\mu}-SLA$ system. MATERIALS AND METHODS. Ten study dies were made using a two-step silicone impression with a dental stone (type IV) from the master die of a tooth. Ni-Cr (NC group) and Co-Cr (CC group) alloy copings were designed using a dental scanner, CAD software, resin coping, and casting process. In addition, 10 Ni-Cr alloy copings were manufactured using the lost-wax technique (LW group). The marginal and internal gaps in the 3 groups were measured using a digital microscope ($160{\times}$) with the silicone replica technique, and the obtained data were analyzed using the non-parametric Kruskal-Wallis H test. Post-hoc comparisons were performed using Bonferroni-corrected Mann-Whitney U tests (${\alpha}=.05$). RESULTS. The mean (${\pm}$ standard deviation) values of the marginal, chamfer, axial wall, and occlusal gaps in the 3 groups were as follows: $81.5{\pm}73.8$, $98.1{\pm}76.1$, $87.1{\pm}44.8$, and $146.8{\pm}78.7{\mu}m$ in the LW group; $76.8{\pm}48.0$, $141.7{\pm}57.1$, $80.7{\pm}47.5$, and $194.69{\pm}63.8{\mu}m$ in the NC group; and $124.2{\pm}52.0$, $199.5{\pm}71.0$, $67.1{\pm}37.6$, and $244.5{\pm}58.9{\mu}m$ in the CC group. CONCLUSION. The marginal gap in the LW and NC groups were clinically acceptable. Further improvement is needed for CC group to be used clinical practice.

• Journal of The Korean Association of Information Education
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• v.21 no.4
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• pp.451-462
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• 2017

This study selected 3D printing that is highly likely to be adopted in schools. This research was conducted in two stages: 1) proposing the learning activity framework for utilizing 3D printing in education, and 2) exploring the potential of integrating 3D printing in the school field. The '3D printing learning activity framework' proposed in this study includes four phases that are categorized according to the complexity of problem-solving processes and collaborative interaction: Step 1 as production through replication, Phase 2 as means of imaginary expression, Phase 3 as near problem-solving, and Phase 4 as expanded problem-solving. Next, we conducted the field study with 23 students in the 6th grade math class where they learned the various solid shapes and volumes through 3D printing-integrated activities. The lesson was considered as Phase 1, which is the production through replication. Overall, the results showed that the participants had positive perceptions about the efficacy of 3D printing activities, the quality of learning experience, and satisfaction. On the other hand, it was found that the usability of 3D printers and CAD program needs further improvement The contribution of this study can be found in the learning activity framework that can guide 3D printing activity design in school, and in the exploration of enhancing the connection between 3D printing activities and curricular relevance beyond simple interest toward a novel technology.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.534-540
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• 2013

Interest of the hand effect on the electromagnetic wave are internationally increasing with the increase of the use of the mobile phone. IEC TC106(International Electrotechnical Commission, Technical Committee 106) promotes international research exchange program in order to reflect the effect of human hands in the standard assessment method of human exposure dosimetry by the electromagnetic wave of mobile phones. Since current commercialized hand phantom is manufactured by taking into account the average size of westerners and provides only one grip posture, it imposes many restrictions on the accurate SAR measurement. Therefore, the development of proper hand phantom accounting for domestic situation and various grip posture capability is essential in order to analyze the accurate effect of human hand on the exposure estimation. In this paper, a jelly hand phantom suitable for Korean was manufactured with various grip posture capability at 835 MHz and 1,800 MHz bands. Although the tolerances of permittivity and conductivity of the manufactured hand phantom are with ${\pm}10%$ each, it was much less than CTIA(Cellular Telecommunication Industry Association) tolerance of ${\pm}20%$ at both bands. Its 3D CAD(3 Dimensional Computer Aided Design) file which was developed can be utilized for the simulation of human hand effect on SAR measurement of mobile phones. The findings in this study can be utilized for the analysis of human hand effect on SAR measurement of a mobile phone.