• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.692-696
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• 2017

The shape of press components is becoming increasingly complex due to customer demands, process shortening and cost savings. In addition, the stability of the pressing process frequently varies during mass production due to the influence of many factors. In order to ensure the process stability, it is necessary to establish a process in which reproducibility is realized in tolerance, which is sufficient for advance study of shape, material, press, mold and lubrication. However, unforeseen changes in process parameters cause disruptions in production line shutdowns and production planning. In this paper, we introduce a method to monitor a real time process by applying a sensor to a press mold. A non-contact type sensor for measuring the flow of a sheet material and an example of an experiment using the optical sensor which is highly applicable to mass production are presented. An optical sensor was installed in a cylindrical drawing mold to test its potential application while changing the material, blank holder force, and drawing ratio. We also quantitatively determined that the flow of other sheet materials was quantified locally using a square drawing die and that the measured value was always smaller than the drawing depth due to the material elongation. Finally, we propose a field that can be used by attaching the sensor to the press mold. We hope that the consequent cost reduction will contribute to increasing global mold competitiveness.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.2
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• pp.165-170
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• 2014

Shear horizontal (SH) waves propagate as a type of plate wave in a thin sheet. The dispersion characteristics of SH waves can be used for signal analysis. Therefore, SH-waves are useful for monitoring the structural health of a thin-sheet-structure. An electromagnetic acoustic transducer (EMAT), which is a non-contact ultrasonic transducer, can generate SH-waves easily by varying the shape and array of magnets and coils. Therefore, an EMAT can be applied to an automated ultrasonic testing system for structural health monitoring. When used as a sensor, however, the EMAT has a weakness in that electromagnetic interference (EMI) noise can occur easily in the automated system because of motors and electric devices. Alternatively, a fiber optic sensor works well in the same environment with EMI noise because it uses a light signal instead of an electric signal. In this paper, a fiber Fabry-P$\acute{e}$rot interferometer (FFPI) was proposed as a sensor to receive the SH-waves generated by an EMAT. A simple test was performed to verify the performance of the FFPI sensor. It is thus shown that the FFPI can receive SH-wave signals clearly.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.328-334
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• 2020

Clinical remounting of complete denture is performed to refine occlusal harmony in maxillo-mandibular relation. It has been reported that patients who used adjusted dentures with clinical remounting felt less complications such as pain and discomfort in mastication. The purpose of this study was to assess effects of clinical remounting with case series. Seven patients with existing complete prosthesis were included. Clinical remounting procedure was done through interocclusal relation recording. In addition, occlusal force was measured with pressure indicating sensor and occlusal contact areas were evaluated with photo occlusion analysis. Occlusal contact areas of prosthesis were enlarged, while bite pressure was not increased. Hit and slide phenomenon of prosthesis was reduced concurrently. Clinical remounting procedure improved denture stability and increased occlusal contact area. Therefore, clinical remounting should be considered.

• Proceedings of the Korean Statistical Society Conference
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• 2002.05a
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• pp.105-112
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• 2002

얼굴인식 기술은 접촉에 대한 거부감이나 불편함이 없이 친숙하고 편리하게 사용자를 식별하고 인식할 수 있으며, 부가적인 센서 장비가 필요없다는 측면에서 개인 인증 및 보안 시스템으로서의 활용성이 매우 높다. 본 논문에서는 여러 가지 장점들을 지닌 얼굴 인식 시스템의 구현 사례를 실시간 얼굴 검출 기술과 특징 추출 기술, 인식 기술로 구분하여 소개한다. 개발된 시스템은 얼굴 검출을 위해서 색상과 에지 성분을 이용하는 복합 알고리즘을 적응하여 실시간 얼굴 탐지를 가능하게 하였고, 추출된 사용자의 고유 얼굴 정보는 최신 인식 기법의 하나인 Support Vector Machine으로 분류, 인식된다. 또한 시스템의 성능을 테스트하고, 실용화 가능성을 모색하기 위하여 하드웨어 임베디드 시스템의 설계 및 구현과정과 조명 및 환경 변화에 따른 시스템의 성능 변화를 객관적으로 검증하기 위하여 다양한 변화 조건을 고려한 한국인 표준 얼굴 데이터베이스를 구축 과정을 소개한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.12
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• pp.1823-1832
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• 2004

In this paper, we proposed a TDC based F/T sensorless active compliance control algorithm for a rehabilitation robot (KARES II). The preference of compliance of the disabled is presented by clinical testing at Korea National Rehabilitation Center with the disabled. The KARES II was designed to work 12 predefined tasks which are very essential for helping the disabled. Among the tasks, some contact tasks between the robot and the disabled exist. Therefore, TDC based F/T sensorless compliance control algorithm is developed for these tasks without additional cost. We verified the proposed algorithm with experiment. Also for the practical use, suitable compliance for contact tasks is chosen by clinical testing at Korea National Rehabilitation Center.

• Electronics and Telecommunications Trends
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• v.31 no.6
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• pp.31-38
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• 2016

인체에 근접한 다양한 휴대 정보 단말기 간의 통신망을 무선으로 구축하는 Wireless Body Area Network(WBAN) 분야에 관한 연구 결과가 국내외에서 지속적으로 발표되고 있다. 이 가운데 인체통신 기술은 인체를 신호의 전송경로로 활용하여 단말기들 간의 연결을 위한 케이블이 필요하지 않으며, 저전력 고속 데이터 전송이 가능하여 WBAN에 가장 적합한 통신 기술로 손꼽힌다. 더불어 인체통신 기술은 사용자의 간단한 접촉을 기반으로 인체 네트워크를 구성하므로 웨어러블 디바이스/센서/단말 및 임플란트 디바이스 분야에 반드시 필요한 핵심 통신 기술로 주목받고 있다. 본고에서는 WBAN에서 최근 인체통신 기술의 개발 동향과 활용 분야 및 표준화 동향에 관하여 살펴보고자 한다.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.358-363
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• 2006

This paper demonstrates a new non-contact electronic joystick using single hall sensor which detects a horizontal vector of the magnetic field. Furthermore, in this paper, it is mathematically modeled that nonlinear characteristics between the output of hall sensor and the movement of joystick bar. The dynamic horizontal vector of magnetic flux is detected by the hall sensor while a permanent magnet is rotated with the joystick bar, which has two dimension detecting area. Using the nonlinear adjustment equations, the output signals of hall sensor have been linearized to give higher accuracy in the two dimension movement. Finally, through the real experiments, it is showed that the single hall sensor structure mechanism is superior to the dual sensor structure in sensing the two-dimensional motion without offset.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2541-2544
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• 2003

새로운 원리에 의한 원격 거리 및 각도측정 시스템［1］［2］(이하 TS, Total Station)을 개발하였다. 본 시스템은 마이크로 터널링 공법의 굴진기의 후미 또는 임의의 기준점에 원격으로 점멸할 수 있는 십자형의 발광체를 부착하고, 추진관에 고정시킨 상하좌우 각도측정 및 비접촉식 레이저 거리측정기가 부착된 무인 원격 제어장치에 의하여 십자형 발광체의 중심을 자동으로 검출한다. 또한. 회전각과 CCD 라인 스캔 센서의 조합에 의하여 각도를 정밀하게 원격 측정하게 된다. 한편 본 시스템을 이용하면 마이크로 터널링 공법에 의한 추진관내의 측정 가능한 범위를 연결하는 위치에 복수의 TS를 배치하여 서로의 위치를 자동으로 계측하고 그들 데이터를 컴퓨터에 의하여 계산함으로써, 맨홀의 임의의 기준점으로부터 굴진기의 현재 좌표를 신속하고 정확하게 계산할 수 있다.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.362.2-362.2
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• 2016

본 실험은 CW (Continuous wave) 주파수를 가진 교류 자기장을 발생시켜 자성나노입자를 가열시키는 것이 목적이다. 이를 위해 CW 주파수 및 SMPS (Switching Mode Power Supply)를 이용해 코일에서 교류 자기장을 발생시키는 평판형 자기장 발생 장치를 자체적으로 개발하였다. 이를 이용하여 인가전압을 변화시키면서 자기장 세기의 변화를 주었다. 평판형 코일 위에는 유리 등의 원형 평판 절연체를 덮고 그 절연체 표면에 웰(Well plate)를 위치시켰고 그 안에 자성나노입자가 포함된 수용액을 넣어 교류 자기장에 노출시켰다. 자기장 측정센서(Magnetic pick up coil, Gauss Meter)를 이용하여 자기장의 세기를 측정하였고, 자성나노입자의 농도, 크기 및 자기장 세기에 따른 자성나노입자의 온도상승효과를 접촉식 온도계를 이용하여 정량적으로 측정하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.134-140
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• 2003

The film sensor is used for measuring pressure distribution at planar area, especially at a small space or gap. The present paper deals with the development of film type sensors and system for pressure distribution measuring. The developed system is consist of (1)film sensor with 40/sup */40 array, (2)PCI interface card with maximum sampling rate of 100㎐, and (3)software for data processing and real-time display. The contact pressure test of wiper blade and front glass of vehicle was performed with wiper blade by 40cm. Generally spring force of wiper arm is designed at 0.7∼1kN. Test results of total force was 9.4N and 7.1N in each driver and passenger toward. The paper suggested possibility for base definition in wiper design. A windshield wiper blade experiment revealed that the system successfully measured the contact force distribution during static state, showing the usefulness of the developed system.