• 한국기계가공학회지
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• 제20권4호
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• pp.113-118
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• 2021

In this study, localized development of a submerged cryogenic pump for use in LNG containers is conducted with large-sized commercial vehicles as the target. The submerged pump installed in an LNG storage container is the key module that supplies fuel to the engine through the reciprocating motion of a piston. Research and development on 660-L fuel containers is performed herein. The target is to achieve a mileage of 600 km or more by applying it to major NGV vehicles worldwide. In this manner, the present study aims to verify the operating mechanisms of the major parts of currently advanced products through reverse engineering in the early development process and draw basic design data.

• 제어로봇시스템학회논문지
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• 제8권9호
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• pp.776-787
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• 2002

Automation of welding process in shipyards is ultimately necessary, since the welding site is spatially enclosed by floors and girders, and therefore welding operators are exposed to hostile working conditions. To solve this problem, a welding mobile robot that can navigate autonomously within the enclosure has been developed. To achieve the welding task in the closed space, the robotic welding system needs a sensor system for the working environment recognition and the weld seam tracking, and a specially designed environment recognition strategy. In this paper, a three-dimensional laser vision system is developed based on the optical triangulation technology in order to provide robots with 3D work environmental map. Using this sensor system, a spatial filter based on neural network technology is designed for extracting the center of laser stripe, and evaluated in various situations. An environment modeling algorithm structure is proposed and tested, which is composed of the laser scanning module for 3D voxel modeling and the plane reconstruction module for mobile robot localization. Finally, an environmental recognition strategy for welding mobile robot is developed in order to recognize the work environments efficiently. The design of the sensor system, the algorithm for sensing the partially structured environment with plane segments, and the recognition strategy and tactics for sensing the work environment are described and discussed with a series of experiments in detail.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.295-298
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• 2010

리서치 시스템에 적용하는 설문조사의 종류에는 전화조사, 온라인조사, 면접조사 등의 방법론이 있다. 현재 국내에서의 리서치 조사방법의 실태는 수작업 상태로 자료를 수집, 검증하고 일부만이 IT를 응용한 반자동화된 시스템을 해외에서 수입하여 사용하고 있다. 본 논문은 글로벌 표준화를 위한 연계 리서치 시스템에 관한 연구이다. 제안 시스템은 국내 여건에 최적화시킨 커스터마이징을 통하여 전화조사, 온라인조사, 면접조사를 전문 인력뿐만 아니라 일반 사용자까지도 쉽고, 빠르게 설문지를 입력할 수 있으며 컴퓨터처리에 의한 결과 데이터를 정확하고 신속하게 고객에게 전달 할 수 있는 서비스 체제를 구현하였다. 특히 본 시스템은 자료입력과 수집의 단계를 기반으로 데이터 분석 및 가공에 필요한 분석과 통계 기능 제공과 오피스 프로그램 및 고급 통계 프로그램인 SPSS와의 호환성을 부가하여 리서치 운영 프로세스의 효율화를 달성하였다. 제안 시스템은 부가적으로 국산화를 통한 수입대체 효과와 함께 리서치 분야의 글로벌 표준으로 제시하기 위하여 설계하고 구현하였다.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.597-608
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• 2021

The control head components used in small military vessels are designed to be domestically produced, prototypes, structural analysis, and casting methods are designed and cast. The control head assembly consists of a lever, an aluminum outside cover, Middle, front gear cover, back gear cover, and a zinc worm gear. In order to reverse the design of each component, 3D scanning device was used, 3D modeling was performed by CATIA, and prototype productions were carried out by 3D printer. In order to reduce the cost of components, gating system is used by gravity casting method. The SRG ratio of 1:0.9:0.6 was set by applying non-pressurized gating system to aluminum parts, 1:2.2:2.0 and pressurized gating system to zinc parts, and the shapes of sprue, runner and gate were designed. The results of porosity were also confirmed by casting analysis in order to determine whether the appropriate gating system can be designed. The results showed that all parts started solidification after filling completely. ANSYS was used for structural analysis, and the results confirmed that all five components had a safety factor of 15 more. All castings are free of defects in appearance, and CT results show only very small porosity. ZnDC1 zinc alloy worm gear has a tensile strength of 285 MPa and an elongation of 8%. The tensile strength of the four components of A356 aluminum alloy is about 137-162 MPa and the elongation is 4.8-6.5%.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1195-1200
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• 2008

This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD(Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin($C_3H_8O_3$). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve. Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2147-2158
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• 2006

The continuous wavelet transform (CWT) has a frequency-adaptive time-frequency tiling property, which makes it popular for the analysis of dispersive elastic wave signals. However, because the time-frequency tiling of CWT is not signal-dependent, it still has some limitations in the analysis of elastic waves with spectral components that are dispersed rapidly in time. The objective of this paper is to introduce an advanced time-frequency analysis method, called the dispersion-based continuous wavelet transform (D-CWT) whose time-frequency tiling is adaptively varied according to the dispersion relation of the waves to be analyzed. In the D-CWT method, time-frequency tiling can have frequency-adaptive characteristics like CWT and adaptively rotate in the time-frequency plane depending on the local wave dispersion. Therefore, D-CWT provides higher time-frequency localization than the conventional CWT. In this work, D-CWT method is applied to the analysis of dispersive elastic waves measured in waveguide experiments and an efficient procedure to extract information on the dispersion relation hidden in a wave signal is presented. In addition, the ridge property of the present transform is investigated theoretically to show its effectiveness in analyzing highly time-varying signals. Numerical simulations and experimental results are presented to show the effectiveness of the present method.

• 한국생산제조학회지
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• 제19권6호
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• pp.883-888
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• 2010

This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD (Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin (C3H8O3). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve, Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.191-192
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• 1998

We report on the design of a low-noise 40 channel SQUID system for biomagnetism. We used low-noise SQUID sensor with the pickup coil integrated on the same wafer as the SQUID. The SQUID electronics were simplified by increasing the voltage output of the SQUID. The SQUID insert was designed to have low thermal load, minimizing the liquid helium loss. The digital signal processing provides versatile analysis tools and the software is based on the object-oriented programming. For the effective localization of the source location, solutions of the inverse problems based on the lead-field and the simulated anneal ins were studied.

• 한국전기전자재료학회논문지
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• 제35권3호
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• pp.232-240
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• 2022

A variable vacuum capacitor (VVC), which is a variable element, is used to match impedance in plasma that changes with various impedance values, and its use is expanding with the rapid growth of the semiconductor business. Since VVCs have to secure insulation performance and vary capacitance within a compact size, electrode design and manufacturing are very important; thus, various technologies such as part design and manufacturing technology and vacuum brazing technology are required. In this study, based on the model of an advanced foreign company that is widely used for impedance matching in the manufacture of semiconductors and displays, a VVC that can realize the same performance was developed. The electrode part was designed, the consistency was confirmed through analysis, and the precision of capacitance was improved by designing a cup-type electrode to secure the concentricity of the electrode. As a result of the evaluation, all requirements was satisfied. We believe that self-development will be possible if satisfactory responses are received through evaluation by VVC consumers in the future.

• 한국실내디자인학회논문집
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• 제20권6호
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• pp.262-271
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• 2011

The purpose of this study was to classify types of family visitors' behaviors more concretely, which could be useful in planning of exhibition spaces in a science museum, with given priority to their behaviors according to interaction between them, and to understand characteristics of the behaviors. With this view, the scope of this study was restricted to subjects, who were family visitors of Gwacheon National Science Museum, consisting of parents and their one elementary school child per family unit. For understanding their behaviors, itinerary tracking and observation method of behavior were conducted. Moreover, for understanding substantial types and characteristics of family visitors' behaviors, multivariate analysis was applied. Accordingly, the results of the study are as follows. First, as a result of factor analysis, two main factors were derived. In other words, they were 'Durability of viewing' as the first and 'Interactivity between family members' as the second, which were shown valid in classification of the types of their behaviors. Second, according to the factors derived, the types of their behaviors were classified into in-depth cooperative viewing, selective independent viewing, interest concentration child-led viewing and consideration parent-led viewing. They were shown valid in topological localization and classification, as a result of analysis of the main factors. Third, in view of common characteristics of the types, it is judged that active orientation prior to regular viewing could encourage visitors coming to the museum for the first time to feel more friendly to unfamiliar exhibition environments, during the initial seek time, and to reduce visual supersaturation. Fourth, it is judged that distributed arrangement of exhibits, which result in continuous standby, could avoid confused visitor circulation by the estimated time required for viewing.