• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.446-452
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• 2016

Recently, heat resistant super alloys (which are wear-resistant, corrosion-resistant, and heat-resistant), have been used as the basic structural material in offshore and petrochemical plants. On the other hand, making valves from very expensive, high heat-resistant alloys increases the production cost and decreases its market competitiveness. To solve these problems, the technique of overlaying only those that flow on the fluid has been used as an effective method. Nevertheless, because the former technique of overlaying the ball is performed manually, it takes too much time and perfect welding is difficult to perform. To solve this problem, this study developed a robot automation system that can make uniformly overlay welding of the ball for ball-valves. The system consists of a 6-axis welding robot with a welding torch and additional 2 axes for the rotation of positioner, the controller, and a robot path OLP (Off-Line Programming). The CAD drawing data was entered in the Off-line program to obtain the robot teaching point and drive source. Overlay welding paths were implemented using Matlab. Through an automated overlaying system that implemented the OLP, the productivity rose 2.58 times, as the amount of time required for work decreased from 88 hours to 41 hours.

• The Journal of Engineering Geology
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• v.27 no.2
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• pp.119-124
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• 2017

The waviness of Large Discontinuity rock is the one of important elements that judges the stability of rock slope. When the waviness of large discontinuity is measured in the field, there are many limitations Therefore this research was carried out to measure waviness of large rock discontinuities using 3D laser scanner to supplement this problem. This research established one 3D model that actual X, Y and Z coordinates through the integrated data gained from one that calculates waviness of base lock using CAD program was compared and analyzed to that of disc-clinometer. As its results, the high reliability of results could be recognized as it belongs to mechanical tolerance $1{\sim}2^{\circ}$ and the results belong to the measured values of Mean DIP and Mean are all within $1^{\circ}$. So, the investigation method of waviness of large discontinuity rock face using 3D laser scanner was verified as more prompt, effective and reliable method than conventional direct site measuring method.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.3
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• pp.132-142
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• 2019

Purpose: The purpose of this finite element analysis study is to introduce the novel Lock screw system and analyze its mechanical property to see if it can prevent abutment screw loosening. Materials and Methods: The Lock screw is a component tightened on the inside of the implant abutment which applies compressive force to the abutment screw head. To investigate the effect, modeling was done using CAD program and it was analyzed by finite element analysis under various load conditions. First, the preload was measured according to the tightening torque of the abutment screw then it was compared with the theoretical value to verify the analytical model. The validated analytical model was then divided into those with no external load and those with 178 N, and the tightening torque of the lock screw was changed to 10, 20, 30 Ncm respectively to examine the property of stress distribution on the implant components. Results: Using Lock screw under various loading conditions did not produce equivalent stresses beyond the yield strength of the implant components. In addition, the axial load was increased at the abutment-abutment screw interface. Conclusion: The use of Lock screw does not exert excessive stress on the implant components and may increase the frictional force between the abutment-abutment screw interface, thus it is considered to prevent loosening of the abutment screw.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.313-322
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• 2022

The number of architects who adopt BIM(Building Information Modeling) as the design method are gradually increasing because of its productivity and efficiency. Climate Change and Global Warming lead to legislation of new energy regulations and strengthen existing ones. The current architectural design methods (2D CAD) take a lot of time and effort to verify energy codes and are hard to adjust according to the design changes. The purpose of this study is to show the effectiveness of the BIM in building envelop energy modeling of the housing project. In the process of design method change, We could contribute to increasing productivity and efficiency in building energy verification through BIM because the updated value could be calculated simultaneously without information omission or recalculation process. The procedure for the study is as follows. Using BIM of the Goldin at Essex Crosing Housing Project by Revit 2011 as a case model, this study analyze the criteria for energy plan to conform to the energy code in NYC. The result value from the setting of the Revit model is compared with the reference value required by the NYC Energy Code. Finally, the data from BIM are entered into COMckeck, the energy verification program provided by U.S. Department of Energy, to check whether the building envelope energy performance conforms to NYC Energy Code.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.2
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• pp.12-19
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• 2022

Propellant grains with embedded metal wires have been used for enhancement of burning rate while maintaining high loading density. For the performance design of a solid rocket motor using propellant grain with embedded metal wires, burn-back analysis is required according to number, location, arrangement angle of metal wires, and augmentation ratio of the propellant burning rate near a wire region. In this study, a numerical method to quickly calculate a burning surface area was developed in response to the design change of the propellant grain with embedded metal wires. The burning surface area derived from the developed method was compared with the results of a CAD program. Error rate decreased as the radial size of the grid decreased. Analysis for characteristics of burning surface area was performed according to the number and location of metal wires, the initial and final phases were shortened and the steady-state phase was increased when the number of metal wires increased. When arranging the metal wires at different radii, the burning surface area rapidly increased in the initial phase and sharply decreased in the final phase compared to the case where the metal wires were disposed in the same radius.

• Journal of Technologic Dentistry
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• v.45 no.2
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• pp.31-38
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• 2023

Purpose: This in vitro study aimed to compare the trueness of 3-unit fixed dental provisional prostheses (FDPs) fabricated by three different additive manufacturing and subtractive manufacturing procedures. Methods: A reference model with a maxillary left second premolar and the second molar prepped and the first molar missing was scanned for the fabrication of 3-unit FDPs. An anatomically shaped 3-unit FDP was designed on computer-aided design software. 10 FDPs were fabricated by subtractive (MI group) and additive manufacturing (stereolithography: SL group, digital light processing: DL group, liquid crystal displays: LC group) methods, respectively (N=40). All FDPs were scanned and exported to the standard triangulated language file. A three-dimensional analysis program measured the discrepancy of the internal, margin, and pontic base area. As for the comparison among manufacturing procedures, the Kruskal-Wallis test and the Mann-Whitney test with Bonferroni correction were evaluated statistically. Results: Regarding the internal area, the root mean square (RMS) value of the 3-unit FDPs was the lowest in the MI group (31.79±6.39 ㎛) and the highest in the SL group (69.34±29.88 ㎛; p=0.001). In the marginal area, those of the 3-unit FDPs were the lowest in the LC group (25.39±4.36 ㎛) and the highest in the SL group (48.94±18.98 ㎛; p=0.001). In the pontic base area, those of the 3-unit FDPs were the lowest in the LC group (8.72±2.74 ㎛) and the highest in the DL group (20.75±2.03 ㎛; p=0.001). Conclusion: A statistically significant difference was observed in the RMS mean values of all the groups. However, in comparison to the subtractive manufacturing method, all measurement areas of 3-unit FDPs fabricated by three different additive manufacturing methods are within a clinically acceptable range.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.348-357
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• 2024

Maneuvering performance is crucial for fishing vessels, especially under operational conditions that involve frequent course changes and weight variations due to catch. Small vessel accidents account for approximately 60% of maritime incidents as of 2022, mainly attributed to collisions and stranding accidents due to insufficient maneuvering performance. Especially, accidents that occur on small vessels less than 10 tons account for about 65% of all accidents. The absence of international standards presents challenges in accurately evaluating the maneuvering performance of small vessels. In this study, a 4.99-ton small fishing vessel was selected as the target, and a 3d-cad model was created. The commercial numerical analysis program STAR-CCM+ was employed to establish a simulation environment for the vessel's maneuvring motion. Based on this standard loading conditions and weight distribution were considered, 10° / 10°, 20° / 20° zigzag tests and 35° turning test were conducted. The results revealed a tendency for decreased yaw and course-keeping performance and improved turning performance as the hull weight increased. However, in partial arrival and full load departure condition, the manoeuvering performance were relatively poor. Based on this, the need for evaluation of maneuvering and standardized criteria of maneuvering performance for safe navigation of small vessels is presented. Furthermore, it is expected that the evaluation results of maneuvering performance in this study can serve as fundamental data for establishing criteria for evaluating the maneuvering performance of small vessels.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.7 s.144
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• pp.1018-1026
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• 2005

Recent development of 3D scanner and software is regarded as a promising method of acquiring replicas from human body indirectly. It would be very helpful if we could predict the characteristics of 2D pattern from the simple parameters related to 3D shape for ordinary user. Therefore, in this study, investigation of 2D pattern of waist/abdominal area from the 3D geometrical model was conducted for the pattern development of waist nipper. To create body models and develop the surface of them, one ortho commonly used CAD/CAM program, IDEAS(UGS-plm solutions, USA) was used. As for the size of the models, the width, thickness, and circumference ranges of adult women's torso reported in National Anthropometric Survey of Korea (1997) were used as a standard model. Seven size variations were made by changing the width of the waist only, from 19 cm to 40 cm. Therefore, simulated body models include not only the normal body but also obese body who has wider waist and abdomen width than hip width. As results, it was found that the curvature of the unfolded 2D pattern around the abdominal area decreases as the waist width increases. As the width of the waist increases more and more, so that the comparative ratios around the torso becomes in abnormal ranges, there appears inflection points and the direction of curvature was changed. 2D Patterns obtained in this research were quantified by curvature, length of the curve and angle of deflection in the reference frame box for the convenience of the actual pattern making process. It was also possible to find that the shape of patterns of abnormal body resulted in a quite interesting change in the curves of 2D pattern, which could be applied to the custom made waist nipper for obese women.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.4
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• pp.443-455
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• 2012

In this research, a woman matched to the average Korean standard size specification of 21-24 years of age was scanned using Cyberware. Rapidform 2004 was used to separate the body zone into fit zone, action zone and design zone, depending on the function of the lower body. Each divided body zone expanded radially using 'offset' by 1.60mm at the cross section of the waist, and 6.36mm at the hip level. Resultant ease values were 1cm and 4cm along the waistline and hipline (respectively), as recommended in previous research. 2C-AN program and Yuka CAD was used to develop a pant pattern from the enlarged 3D body surface blocks. A total of five pants were constructed using conventional fabrics for light weight formal pants. The appearance of the experimental pants were evaluated by five clothing-major evaluators using a questionnaire that consisted of 21 questions. In addition, functional aspects of the experimental pants were also evaluated by wearer while performing five postures for the measurement of ease of movement. It was found that, the method of regional offset and suggested 3D to 2D pattern development generate reasonably good pant patterns. Among the pattern block arrangements, the method B was evaluated as the best way to generate formal pants from the tight-fit pattern, which fit smoothly over the lower body for maintaining ease of movement.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.5 s.164
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• pp.742-752
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• 2007

The purpose of this study is the image of clothing according to the change of the dots' size was analyzed and its influence on the formation of the image of polka dots clothing was investigated. White waterdrop patterns were designed on the 12 kinds of black texture using Photoshop and CAD program in regular arrangement of diamond figure, composed of white waterdrop(0.5cm, 1.0cm, 1.5cm and 2cm in diameter) and interval(diameter : interval-1 : 1, 1 : 2, 1 : 4). Applying above specification, the photograph stimulus of 12 kinds of X-line one-piece dress with wide square neckline and without sleeve or detailed ornament was presented on a screen in the same size as when putting it on. The image of polka dots clothes was investigated by questionnaire survey. The object of the study was 320 females aged between 16 and 29. Factor analysis, one-way ANOVA, $Scheff\acute{e}$ verification and two-way ANOVA using SPSS 10.0 were carried out for data analysis. Followings are the results: 1) The image of polka dots clothing consists of 4 factors as aesthetics, brevity, dynamism and lightweight. 2) The size of the dot has a great influence on the formation of the image of polka dots clothing. 3) The evaluations of the image of polka dots clothing were different depending on the age and physical image, the personal characteristics of the object of investigation.