• 한국정밀공학회지
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• 제26권2호
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• pp.118-125
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• 2009

This paper reports the size classification of nanoparticles as well as electrical tuning techniques for the cut-off diameter and collection efficiency. Classifying particles < 100 nm in diameter is quite a technical challenge using a virtual impactor with the cut-off diameter being determined geometrically. However, the proposed virtual impactor can classify particles <100 nm and tune the cut-off diameter by electrically accelerating the particles. The cut-off diameter of the proposed device was tuned from 15 to 50nm.

• 대한기계학회논문집
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• 제15권1호
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• pp.285-291
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• 1991

본 연구에서는 800 1pm인 대유량을 처리하고 공기중 1.8~4.5$\mu\textrm{m}$ 입자를 효율 적으로 선별하여 농축시키는 슬릿형 2단 가상충돌기를 설계 제작하고 그 성능이 평가 되었다. 즉, 첫째단과 둘째단에서 4.5$\mu\textrm{m}$과 1.8$\mu\textrm{m}$이 각각 50%의 효율로 분리되도록 설계되었다. 즉, 첫째단과 둘째단에서 4.5$\mu\textrm{m}$과 1.8$\mu\textrm{m}$이 각각 50%의 효율로 분리되도 록 설계한다. 설계인자(design parameter)들을 결정하기 위하여 먼저 슬릿형 노즐의 1단 가상충돌기의 분리효율(separation efficiency)에 대한 실험을 통하여 50% 커트오 프 Stokes수를 구하고, 이를 기초로 하여 2단 가상 충돌기의 주요치수와 작동조건을 결정하였다.

• 한국정밀공학회지
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• 제19권12호
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• pp.86-92
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• 2002

This paper presents a new model of NC verification in NC milling using z-map. The model can describe the motion of machine tool like a real machine effectively. The model uses x, y, and z directional feed rate as well as cutting data for modeling Z-map of workpiece. The model verifies the over-cut, the under-cut and the surface topography using NC codes and cutting conditions. To investigate the performance of the model, simulation study was carried out. As the results, the model gave the geometry accuracy of workpiece, the surface topography, and the chip loads.

• 한국기계가공학회지
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• 제18권7호
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• pp.63-70
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• 2019

An electro-aerodynamic lens for improving the performance of virtual impactor has been proposed in this study. ANSYS FLUENT Release 16.1 was used for numerical analysis of virtual impactor with and without the electro-aerodynamic lens, used to collimate the incoming aerosol particles into a particle beam before injecting the particles into the virtual impactor. Particles supplied to the electro-aerodynamic lens were assumed to be highly charged. By using an aerodynamic lens before the virtual impactor, without any electrostatic effect, it was found that the cut-off diameter of the virtual impactor was reduced from $4.2{\mu}m$ to $0.68{\mu}m$ and that the fine particle contamination problem became more serious. However, by employing the combined electrostatic and aerodynamic effects, that is, by applying electric voltage potential to the electro-aerodynamic lens, the cut-off diameter was found to be further reduced to $0.45{\mu}m$ and the fine particle contamination was eliminated.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.173-179
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• 2003

In this paper, a real-time multibody vehicle dynamics and control model has been developed for a virtual reality intelligent vehicle simulator. The simulator consists of low PCs for a virtual reality visualization system, vehicle dynamics and control analysis system a control loading system, and a network monitoring system. Virtual environment is created by 3D Studio Max graphic tool and OpenGVS real-time rendering library. A real-time vehicle dynamics and control model consists of a control module based on the sliding mode control for adaptive cruise control and a real-time multibody vehicle dynamics module based on the subsystem synthesis method. To verify the real-time capability of the model, cut-in, cut-out simulations have been carried out.

• 한국정밀공학회지
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• 제12권6호
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• pp.105-111
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• 1995

The inverse dynamic equations for 5 link robot including a closed chain have been derived. The closed chain is virtually cut open, and the kinematics and dynamics of the virtual open chain robot are analyzed. The constraints are applied to the virtually cut joints by the Jacobian matrix which represents the configuration of the closed chain. The topology of tree structrued open chain robot is described by a FATHER array. The FATHER array of a link indicates the link tha tis connected in the direction of base link. Based on the inverse dynamic equations, the torque sensitivity models of the 5 link robot have been developed. The sensitivity models characterize the sensitivity of the driving torque with respect to the link parameters. All the procedures are illustrated through the 2 link robot.

• 대한가정학회지
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• 제46권2호
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• pp.73-83
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• 2008

The focus of this research was concerned with studying lower body type for Korean adult females. information from the measuring values based on research on the physical standard of the nation(2004) were summarized, in addition a factor of the need for appropriate fit in boots cut jean wear, basic lower body part applying to each item had to be taken into consideration to enhance sizing suitability. The body type are classified into three kinds by means of factor analysis and cluster analysis. Type 1 referred to the fat lower body, having thick rounding waist. compared to other body parts, and long leg according to its proportion. Type 2 represented medium stature but with a large skeleton structure of lower body. Type 3 represented a the long lower body having slender rounding waist. This study was attempted to evaluate the fitness of boots cut jeans pattern for women using 3D Clothes Modeling Software.

• 한국의류학회지
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• 제48권4호
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• pp.744-755
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• 2024

This study analyzes the characteristics, product dimensions, and ease of haenyeo suits to inform their reproduction. Large, medium, and small haenyeo suits were collected from four manufacturers in Jeju, and their components, cut styles, product dimensions, and ease were analyzed. In the current haenyeo suit design, the upper suit has a collar and a crotch, while the lower suit has a high rise with a gusset. Additionally, there are darts behind the neck in the upper suit and behind the knees in the lower suit. Haenyeo suits have a three-dimensional shape that accommodates the postures needed for haenyeo's underwater activities. The upper suit is finished with a cuffed hem or an uncuffed side seam with a diagonal or stepped cut. The lower suit is cut and sewn with the waist and hem at right angles or with the hem diagonal to the waistline. Haenyeo suit dimensions vary between manufacturers, and the models' body dimensions show that there is little or no ease. In conclusion, haenyeo suit manufacturers currently use the same components; however, they differ in terms of cut styles, sewing methods, dimensions, and designs.

• 한국항공우주학회지
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• 제40권5호
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• pp.423-430
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• 2012

본 논문에서는 기하학적 비선형 후좌굴 유한요소 해석을 통하여 얇은 멤브레인에서 주름 발생이 컷의 진전방향에 미치는 영향을 연구하였다. 해석에는 양단에 인장을 받고 있고 중앙에 기울어진 컷을 가진 직사각형 멤브레인을 고려하였다. 주름이 발생한 경우와 주름이 발생하지 않은 경우에 대해 각각 해석을 수행하여 컷의 진전각도 및 $J$-적분값을 비교하였다. 컷의 진전각도는 에너지 방출률이 최대인 방향, $K_{II}$의 값이 0이 되는 방향을 구하는 방법 및 접선응력이 최대인 방향을 구하는 방법을 사용하여 계산하였다. 또한 다양한 컷의 초기방향각을 고려하여 각도에 따른 주름의 영향을 조사하였으며 가상의 미소크기의 컷을 반복적으로 진전시켜 컷이 전파되는 경향도 알아보았다.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2000년도 추계학술발표논문집
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• pp.1-5
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• 2000

With the advent of the internet era, web-based virtual training system is gaining its importance in recent years. Because of the fact that the training can take place in any place and at any time, the virtual system is now replacing many of the conventional off-line classes. Hardware environments such as communication bandwidth and computer performance gets fast enough to accommodate the virtual education. Based on the observations on current virtual training system, this paper proposes three critical design rules required when developing a new virtual training system: i) With conceptual mapping, the menu hierarchy can be organized in a clear-cut manner, ii) Extensive use of multimedia tools can help students keep their attention to the lecture materials, and iii) Provision of interaction mechanisms helps students to gain their identity and motivation.