• International Journal of Precision Engineering and Manufacturing
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• 제7권2호
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• pp.56-59
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• 2006

A vibrational model of powder transfer equipment based on the lumped parameter method was developed, in which the operating motion consists of surging, bouncing, and pitching. After decoupling the equation of motion, the vibrational excitation source of the pitching motion was removed. So the designers are able to plan the optimum design to adjust the motion trajectory of the powder transfer equipment. That is, a procedure to adjust the motion trajectory of powder transfer equipment by changing design specifications such as the installation position, the direction of the motor, the driving speed, the mass unbalance, the stiffness coefficient, and the installation position of the support spring, is presented in this paper. The powder transfer equipment manufactured according to the results of this study did not suffer fatigue destruction, since the maximum stress on the basket structure was sufficiently small.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1320-1322
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• 1994

Photoisomerization characteristics of 4-octyl-4'-(5-carboxy-pentamethyleneoxy) azobenzene molecules (8A5H) were attained by measurement of absorbtion spectra. 8A5H in chroloform($6.0{\times}10^{-5}[M/l]$) shows trans to cis and cis to trans isomerization by irradiation of lights of 360[nm] and 450[nm] wavelength. From LB monolayer films of 8A5H, also the cis/trans photoisomerization was obtained and it has reversibility and memory characteristics. We are now trying to detect these properties of 8A5H electrically. On this paper, we investigated the structural changes of monolayer on the water surface by measuring the displacement current as a preliminary experiment. The measuring system was constructed at home-made Kuhn type LB(Langmuir-Blodgett) deposition apparatus. 8A5H solution was spreaded at the air-water interface and the currents induced by the dynamic behavior of molecules were measured when the molecules were pressed by barrier. The reversibility of displacement currents by compression and expansion was obtained from 8A5H molecules, which shows the compressed molecules have a tendency to disperse after the compression. From this experiment, we conclude that the behavior of molecules on water surface can be monitored electrically by using this current measuring method, and this method can also be applied to detect the photoisomerization of monolayers on water surface.

• 한국건설관리학회논문집
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• 제23권1호
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• pp.64-72
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• 2022

흙막이 공사는 지하굴착을 수행하는 건설공사에서 필수적으로 적용되는 공사 기법으로, 공사 규모와 관계없이 흙막이의 계측관리는 필수적이다. 그러나 굴착깊이 10m 미만에 해당되는 소규모 건축현장(총 공사비 20억 내외)의 경우에는 1) 시공업체의 영세성, 2) 현장관리자의 역량 부족, 3) 계측기기 설치·해체 및 변위분석의 복잡성 등의 문제점으로 인해 흙막이의 계측 관리가 제대로 수행되고 있지 않는 실정이다. 상기 문제점을 해결하는 선행연구 분석 결과, 대부분의 선행연구에서는 값비싼 3D 스캐너를 활용하거나 다수의 계측기기를 설치해야 되는 문제점이 있어 소규모 건설현장에 이를 적용하는 것은 어려운 것으로 분석되었다. 따라서 본 연구의 목적은 하나의 계측기기를 활용하여 흙막이 구조체의 변위를 파악할 수 있는 레이저 센서 기반 흙막이 구조체 변위 계측 시스템의 개념 디자인을 제안하고 개념 디자인에 적용된 요소기술의 변위 인식 성능을 검증하는 것이다. 요소기술은 2D 레이저 스캐너가 선정되었으며, 선정된 2D 레이저 스캐너를 활용하여 개념디자인이 제안되었다. 2D 레이저 스캐너의 변위 인식 검증 결과, 15mm의 변위는 충분히 파악 가능한 것으로 분석되었다. 추후, 제안된 개념디자인이 개발되고 현장에 적용될 경우 소규모 건설현장의 안전사고 저감에 기여할 것으로 분석된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.378-382
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• 2005

The opening of high speed railway upgraded our land transportation speed limit, causing lots of changes including living and culture and also paving the way for stepping up the railway technology. However, it is also true that we had a limit to adopt the existing railway system structured for 150km/h to the new structure requiring a higher speed of approximate 300km/h due to technological, based on the time and experience. More importantly, heading toward a step of operating such a high speed railway system, it has been practically and quickly proposed that the railway needs high speed railway engineering, maintenance technology of parts of the vehicles to have a stable maintenance foundation and localization of major parts. Therefore, this study was intended to research the actual displacement characteristics in runningg on an actual track for the purpose of developing the protective and maintenance technology of springs and dampers, which are core parts among suspension elements of a high speed railway vehicle. For this, it was researched the actual vehicle test and its interpretation centered on primary spring, which is used for the suspension system of a bogie, body-body dampers and body-bogie yaw damper. Also, to analyze the displacement characteristics of suspension system in the actual conditions of high speed railway vehicles, a vehicle‘s dynamic characteristics was analyzed and interpreted. At the same time, a tester for measuring the actual displacement of such suspension elements was designed and attached to actual vehicles, to measure the displacements that occur in running it on the Seoul-Busan line, one of major lines serviced by KTX. The displacement data gained from the test with actual vehicles was analyzed for its displacement distribution depending on the service sections and frequency, with which the valuable data necessary for any potential breakdown or maintenance in the future could be obtained.

• 드라이브 ㆍ 컨트롤
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• 제15권1호
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• pp.1-9
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• 2018

The spool displacement of directional control valve can be considered as the standard signal to measure the bandwidth frequency of a directional control valve. When the spool displacement is not available, the metering-orifice system is implemented in this research as an alternative way of measuring the 90 degrees phase bandwidth frequency of the hydraulic directional control valve. The inertia effect on the transmission line oil induces the phase lead of the valve load pressure when compared with the phase of spool displacement. The capacitance effect of the oil induces the phase lag of the valve load pressure. The phase of the load pressure can be adjusted to be the same as that of the spool displacement by controlling the opening area of the metering orifice. A series of experiments were conducted to verify the effectiveness of the metering orifice. The 90 degrees phase bandwidth frequency measured from the valve load pressure was significantly deviated in some cases from the frequency of the spool displacement. The metering orifice was hard to be applied to measure the -90 degrees phase bandwidth frequency of the high precision.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.303-310
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• 2011

This paper is focused on development of models for measuring lateral and vertical track irregularities from corresponding accelerometers of an in-service high-speed train. Generally, the track irregularity was measured by a special railway inspection vehicle or system with contact or non-contact sensors. However, the sensors are very expensive and vulnerable to a harsh environment. Displacement estimation from an inertial measurement unit and its wave-band filtering was already developed in the previous study, and it was found that their results included not only the track irregularities but also other information such as phase delay of the applied filters, and suspension and conicity of the wheel. To identify the track irregularities from those results, a compensation filtering method was proposed. Each directional compensation filter was derived by using a system identification method with the estimated directional displacement as input and the corresponding track irregularities as output. In this paper, they are integrated into a model for each direction and applied to the measured lateral and vertical acceleration data from the axle-box and bogie of an in-service high-speed train. Their results are compared with the data from the track geometry measurement system. From the comparison, the proposed models are a useful tool for the measurement of the track irregularities using accelerometers of in-service high-speed trains.

• 한국측량학회지
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• 제27권3호
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• pp.385-392
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• 2009

본 연구의 목적은 멀티 GPS 센서를 이용하여 장대교량의 형상을 실시간으로 모니터링 하고 관리 할 수 있는 방안에 대하여 연구하는데 있다. 멀티 GPS 센서를 장대교량의 주요 지점에 설치하고 변위를 실시간으로 측정함으로써 장대교량의 3차원적인 형상거동을 관리 할 수 있을 것으로 판단된다. 본 연구에서 개발한 형상관리시스템은 교량의 전체적, 지점별 변위정보를 수치화, 시각화하고 위험발생에 따라 능동적으로 대응이 가능하며 측정데이터의 DB화를 통해서 계측정보를 실시간으로 관리하고 제공 할 수 있을 것으로 판단된다. 또한 GPS센서를 이용한 형상관리시스템은 GPS 센서를 이용한 장대교량의 3차원 절대변위 및 거대변위의 효과적인 측정에 의한 교량의 전체적인 형상관리에 활용할 수 있을 것으로 판단된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.61-67
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• 1997

The electronic speckle pattern interferometer (ESPI) has been applied to many technical problems such as deformation and displacement measurement, strain visualization and surface roughness monitoring. In this study, we used an ESPI system based on the dual beam speckle interferometer method in order to measure in-plane displacement and vibration mode using the ESIP technique. This research was carried out for the purpose of applying the vibration analysis method employing Electro-Optic holographic interference technique to the vibration analysis of uniform rectangular cantilevers plate(SS400,STS304) with cantilevers span to breadth ratio of 150 by 75. And thickness of 1mm and 0.8mm respectively. We improved the ESPI technique in order to obtain the distribution of displacement component resolved in one direction through a CCD camera combined with an image processing system. To certify and to assess the accuracy in measuring by this ESPI, the results obtained with the speckle method and vibration mode analysis are to be compared with those results by Warbuton's Theoretical expression and vibration made in FEM analysis.

• 한국멀티미디어학회논문지
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• 제17권8호
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• pp.937-945
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• 2014

Multi-modal biometric system can use another biometric trait in the case of having deficiency at a biometric trait. It also has an advantage of improving the performance of personal identification by using multiple biometric traits, so studies on new biometric traits have continuously been performed. The inner face of finger is a relatively new biometric trait. It has two major features of knuckle lines and wrinkles, which can be used as discriminative features. This paper proposes a finger identification method based on displacement vector to effectively process some variation appeared in contactless hand image. At first, the proposed method produces displacement vectors, which are made by connecting corresponding points acquired by matching each pair of local block. It then recognize finger by measuring the similarity among all the detected displacement vectors. The experimental results using pubic CASIA hand image database show that the proposed method may be effectively applied to personal identification.

• 한국자동차공학회논문집
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• 제1권2호
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• pp.125-133
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• 1993

Electronic Speckle Pattern Interferometry(ESPI) using a CW laser, a video system and image processor was applied to the rotating displacement of rigid body. ESPI require no special surface preparation or attachments and displacements between any two arbitrary points on the surface can be measured. The characteristic speckle pattern formed when imaging a scattering surface illuminated by laser light retains phase information, which can be used for interferometric measurement of surface displacement. The application of this principle to measuring in-plane displacement resolved in one direction is described, together with the novel use of television equipment to detect and process the information contained in the speckle pattern. This is faster, and more convenient and versatile than customary photographic methods.