• 한국시뮬레이션학회논문지
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• 제32권3호
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• pp.1-8
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• 2023

영상레이더(SAR)에서 인공표적에 대한 모델링은 주로 3차원 CAD(Computer Aided Design) 모델의 면(face) 및 모서리(edge)에서 반사되는 레이더 신호를 광선추적(ray-tracing) 방식으로 시뮬레이션하고 있고, 지구 표면의 클러터(clutter)에 대한 모델링은 영상레이더 이미지 자체에 대한 통계학적(statistical) 분석을 통해 분포(distribution) 특성이 유사한 종류들을 구분하는 방식을 사용하고 있다. 본 논문에서는 지상의 인공표적 및 지표면의 배경 클러터를 3차원 점구름(point cloud) 산란점(scatterer point) 모델로 만들고 두 개의 모델이 통합된 상황에서 계산적(computational)인 신호처리 과정을 통해 영상 레이더 이미지를 생성하였으며, 이것을 실제 차량탑재형 영상레이더 시스템의 스트립맵(stripmap) 이미지 생성 결과 및 전자기적(EM) 모델링 또는 통계학적 분포 모델을 사용하여 분석한 결과와 유사한 지 비교해 보았다. 모델링 대상은 지상의 인공표적인 교량(다리)을 선정 했는데, 그 이유는 교량의 경유 주변에 수면과 지면이 같이 존재하는 특성이 있고 또한 군사용 및 민간용 활용에서 모두 관심이 많은 표적이기 때문이다.

• 한국의류산업학회지
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• 제9권6호
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• pp.581-588
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• 2007

The purposes of this study are to look into the formative characteristics of the miniskirt and to evaluate the visual effects and images according to changes in the silhouette and length of the miniskirt from analyzing the mini skirt style shown in 2007 S/S domestic fashion. The miniskirt style shown in 2007 S/S domestic fashion was analyzed with pictures from a fashion website "Interfashion Planning" from Feb. to May of 2007. As a result, the basic lines of the miniskirt are classified into two types according to the side line. The lengths of miniskirts are classified into five steps of 25 cm, 27.5 cm, 30 cm, 32.5 cm, and 35 cm from the natural waistline. The stimuli were produced with imaginative sewing system 3D CAD of i-design series. For the visual evaluation according to changes in the silhouettes and length of the miniskirt, we used 13 pairs of items to find the visual effects, and 23 pairs of adjectives to measure the visual images. The stimuli and adjectives were randomly given to the evaluators and were evaluated by the 7-point likert type scale. Data we got from this experiment was analyzed statistically by using the SPSS 12.0 and practiced the Factor Analysis and Correlation Analysis. Formative characteristics of miniskirts can be found in the lines, colors, and materials that are the elements of fashion designs, colors and materials are the characteristics of the cloth that is the medium of the expression of designs. The result of factor analysis of visual effects and visual images according to changes in the silhouettes and lengths of miniskirts, the visual effect was composed of the three factors of the length of the lower body, the thickness of the lower body, and the shape abdomen and it was showed that these three factors occupied 63.6% of the total variance. The visual image was composed of four factors of elegance, personality, attraction, maturity and these four factors got 67.6% of the total variance.

• 한국BIM학회 논문집
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• 제3권3호
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• pp.9-18
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• 2013

In case of applying the BIM method in the civil engineering of irregularly shaped structure, BIM method began to be introduced in the current building engineering area compared with the expected effects of the relatively high construction productivity has been recognized. In this paper, I have developed quantity calculation algorithms applying it to earthwork and bridge construction, tunnel construction, retaining wall construction, culvert construction and implemented BIM based 3D-BIM Modeling quantity calculation. Structure work in which errors occurred in range between -6.28% ~ 5.17%. Especially, understanding of the problem and improvement of the existing 2D-CAD based of quantity calculation through rock type quantity calculation error in range of -14.36% ~ 13.07% of earthwork quantity calculation. It's benefit and applicability of BIM method in civil engineering. In addition, routine method for quantity of earthwork has the same error tolerance negligible for that of structure work. But, rock type's quantity calculated as the error appears significantly to the reliability of 2D-based volume calculation shows that the problem could be. Through the estimating quantity of earthwork based 3D-BIM, proposed method has better reliability than routine method. BIM, as well as the design, construction, maintenance levels of information when you consider the benefits of integration, the introduction of BIM design in civil engineering and the possibility of applying for the effectiveness was confirmed. In addition, as the beginning phase of information integration, quantity document automation program has been developed for activation of BIM. And automatically enter the program code number, linkage and manual volume calculation program, quantity document automation programs, such as the development is now underway, and step-by-step procedures and methods are presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.743-748
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• 2005

In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience for clarity. Therefore, a new rapid manufacturing process using the hot tool, Rapid Heat Ablation process (RHA), has been developed. In this paper, the hot tool for RHA process is devised to minimize radius of heat affected zone and also investigated for verification. TRIZ well-known as creative problem solving method is applied to overcome the contradictive requirements of the hot tool. For the detailed design of the hot tool, numerical model is established with several assumptions. Based on the numerical results, surface temperature is measured with K-type thermocouple at the predetermined location. Numerical and experimental results show that the devised hot tool fulfils its requirements. It verifies the practicality of hot tool that the hemisphere shape is ablated using the hot tool with stair structure.

• 한국의류학회지
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• 제22권3호
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• pp.312-320
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• 1998

The purposes of this study were 1) to extend the gestalt theory in an attempt to explain the effect of garment clues(formality, color) perceiver's gender, and contexts on impression formation of a male high school teacher, and 2) to found out high school students' attitude toward their teacher's school outfits. The experimental design was a quasi-experimental with full factorial design of 4 independent variables : 3(formality levels)x2(garment colors)x2(perceiver's gender)x2(con- texts) The experimental materials developed for the study were a set of stimuli and response scale. The stimuli consisted of 12 color photographs produced by CAD system and response scale constituted of 28 bipolar adjectives representing personal traits. In addition to the qualitative research was also performed. The subjects composed of 277 male and 291 female high school students' in Taejeon city and research was a between subject design. The data was analysed by factor analysis, ANOVA, Duncan's multiple range test. The major findings drawn from this study were as follows: 1. The perceivers impression were consisted of 4 major dimensions; evaluation, sociability, attractiveness, potency. 2. All the independent variables showed some significant impression effects on selected dimensions. Garment color indicate the most significant effects among the 4 independent variables and garment formality showed least effects. 3. The subjects of the study preferred suits(highest formality level garment) to semi-formal or casual outfits for male teacher's school outfits. In conclusion, 4 independent variables affected differently 4 major impression dimensions and garment formality and contexts showed significant interaction effect, this results supported the gestalt theory of impression formation.

• 한국BIM학회 논문집
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• 제12권4호
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• pp.19-31
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• 2022

With the development of 3D-based CAD (Computer Aided Design), attempts at freeform building design have expanded to small and medium-sized buildings in Korea. However, a standardized system for continuous utilization of shape data and BIM conversion process implemented with 3D-based NURBS is still immature. Without accurate review and management throughout the Freeform building project, interference between members occurs and the cost of the project increases. This is very detrimental to the project. To solve this problem, we proposed a continuous utilization process of 3D shape information based on BIM parameters. Our process includes algorithms such as Auto Split, Panel Optimization, Excel extraction based on shape information, BIM modeling through Adaptive Component, and BIM model utilization method using ID Code. The optimal cutting reference point was calculated and the optimal material specification was derived using the Panel Optimization algorithm. With the Adaptive Component design methodology, a BIM model conforming to the standard cross-section details and specifications was uniformly established. The automatic BIM conversion algorithm of shape data through Excel extraction created a BIM model without omission of data based on the optimized panel cutting reference point and cutting line. Finally, we analyzed how to use the BIM model built for automatic conversion. As a result of the analysis, in addition to the BIM utilization plan in the general construction stage such as visualization, interference review, quantity calculation, and construction simulation, an individual management plan for the unit panel was derived through ID data input. This study suggested an improvement process by linking the existing research on atypical panel optimization and the study of parameter-based BIM information management method. And it showed that it can solve the problems of existing Freeform building project.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.591-594
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• 2000

This paper describes a research work of developing a computer-aided design of product with bending and piercing for progressive working. An approach to the system for progressive working is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer and is composed of four main modules, which are input and shape treatment, flat pattern layout, strip layout and die layout module. Based on knowledge-based rules, the system is designed by considering several factors such as radius and angle of bend, material and thickness of product, complexities of blank geometry and punch profile, bending sequence, and availability of press. Strip layout drawing generated by the piercing processes with punch profiles divided into for external area is simulated in 3-D graphic forms, including bending sequences for the product with piercing and bending. Results obtained using the modules enable the manufacturer for progressive working of electronic products to be more efficient in this field.

• 한국해양공학회지
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• 제24권1호
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• pp.178-184
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• 2010

Today, there has been a decrease in international shipping because of the weakening in global economies. Therefore, shipowners are thinking more about Floating Production Storage and Offloading (FPSO), which can perform functions related to the transporting, storage, and tracking of crude oil from oil wells. Given the huge expense of these special ships, shipowners require workers who can solve problems quickly and secure sustainable production functions in this age of globalization. Furthermore, it is important to design, construct, and maintain facilities so that a ship remains in operation over a long term. This paper discusses a system that uses knowledge-based AR to help workers improve their understanding and deal with pipeline equipment problems safely. In addition, it displays a 3CAD model and status information for products to improve their recognition on the FPSO that they intend to inspect. At the same time, the system works quickly and offers solutions for dangerous circumstances or malfunctions. It thus helps to maintain the functionality of the FPSO throughout its life-cycle.

• 산업경영시스템학회지
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• 제41권4호
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• pp.91-100
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• 2018

The setting of values on door hinge mounting compensation for door assembly tolerance is a constant quality issue in vehicle production. Generally, heuristic methods are used in satisfying appropriate door gap and level difference, flushness to improve quality. However, these methods are influenced by the engineer's skills and working environment and result an increasement of development costs. In order to solve these problems, the system which suggests hinge mounting compensation value using CAE (Computer Aided Engineering) analysis is proposed in this study. A structural analysis model was constructed to predict the door gap and level difference, flushness through CAE based on CAD (Computer Aided Design) data. The deformations of 6-degrees of freedom which can occur in real vehicle doors was considered using a stiffness model which utilize an analysis model. The analysis model was verified using 3D scanning of real vehicle door hinge deformation. Then, system model which applying the structural analysis model suggested the final adjustment amount of the hinge mounting to obtain the target door gap and the level difference by inputting the measured value. The proposed system was validated using the simulation and showed a reliability in vehicle hinge mounting compensation process. This study suggests the possibility of using the CAE analysis for setting values of hinge mounting compensation in actual vehicle production.

• 대한조선학회논문집
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• 제46권5호
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• pp.545-551
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• 2009

In naval architecture and offshore engineering, the development and a broad use has been achieved in the field of flow control valves for pipe system. Butterfly valves are also widely used for flow control, but there are not many studies for triple-eccentric butterfly valves. Moreover, if the fluid of pipeline flows in the bi-direction then it makes more complicate to adapt triple-eccentric butterfly valves to flow control. In this study, we are trying to develop a bi-directional triple-eccentric butterfly valve through sealing mechanism and stem design study. Digital mockup using 3D CAD was constructed for shape interference check and structural analysis was conducted for structural safety. Also we performed leakage test to check out the durability of the bi-directional pressure for the developed valve.