• 한국소음진동공학회논문집
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• 제26권2호
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• pp.165-171
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• 2016

A prosthetic knee for above-knee (AK) amputee is categorized into passive and active type. The passive prosthetic knee is generally made by elastic material. Although AK amputee can easily walk by using passive prosthetic leg, knee joint motions are not similar to ordinary persons. The active prosthetic leg can control the knee angle owing to the actuator and microprocessor. However, the active type is not cost-effective and the stability may be lost due to the malfunction of sensors. In order to resolve these disadvantages of passive and active type, a semi-active prosthetic knee which can control the knee angle is proposed in this work. The proposed semi-active one requires a less input energy but provides active type performance. In order to achieve this goal, in this work, a semi-active prosthetic knee using magneto-rheological (MR) damper for AK amputees is designed. The MR damper can support the weight of body by using less energy than actuator of active prosthetic. It can control knee angle by inducing the magnetic field at the time of stance phase. This salient characteristic is evaluated and presented in this work.

• 센서학회지
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• 제11권6호
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• pp.365-370
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• 2002

교류 220V에 의해 동작하는 점핑링 장치를 제작하고 광센서를 사용하여 링의 높이정보를 받아 부상한 링의 높이를 실시간으로 검출하고 교육적 효과를 높이기 위해 디지털 높이정보를 아날로그 변환하여 쉽게 높이를 알 수 있도록 하였다. 교육용 시스템을 직접 제작하여 시스템을 모형화하여 제어신호를 구하고 제어 프로그램에 의해 원하는 높이로 링을 부상할 수 있도록 하였다. 본 논문은 광센서를 사용하여 링의 위치를 실시간으로 검출하였고 광센서의 배열과 높이 정보를 발광다이오드 5개로 디지털 값을 보여주었고, D/A변환하여 교육용 시스템을 제작하여 A/D 변환기를 통해 데이터 신호처리 하였다. 교육용 시스템을 모형 화하여 원하는 링의 높이를 실시간으로 제어 할 수 있게 하였다.

• 비파괴검사학회지
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• 제20권1호
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• pp.46-53
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• 2000

석유화학 설비 등과 같은 노출 배관의 결함을 검출하는데 효율적으로 이용될 수 있는 자왜형 초음파 센서를 제작하였다. 최대의 초음파 발생 효율을 얻기 위한 최적 조건을 설정하였으며, 실험에 사용된 배관의 경우 $250{\sim}350Oe$의 정자기장이 최적이었으며, 180kHz의 주파수를 갖는 초음파를 발생시키기 위해서는 15mm 폭의 코일을 사용하는 것이 가장 좋았다. 최적의 조건에서 발생된 초음파는 50m 이상을 충분히 진행할 수 있으며, 결함의 단면적이 증가함에 따라 수신된 결함 신호는 직선적으로 증가함을 확인하였다.

• 한국군사과학기술학회지
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• 제6권4호
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• pp.22-28
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• 2003

In the conventional weapon system, such as gun and small arms, it Is a general trend that for maximization of its performance and enhancement of its effectiveness, the firing control system(FCS) is developed and applied with the guns and small arms in the world. The FCS of the small arms for infantry man is composed of a few of sensors for acquisition of input data of FCS, such as range measurement, position sensing of weapon, temperature, etc., computer, displayer and power pack, and also the air burst munition is developed in parallel for the maximization of FCS's effectiveness. Since the flight time setting fuze for the air burst munition is adapted for next me, the measuring device of the muzzle velocity is needed to overcome the variation of muzzle velocity due to producing procedures and the differences of the using temperatures and so maintain the burst position accuracy This paper contained the technical information on the development of the measuring device of muzzle velocity, which designed in compact & light weight configuration with reliability and accuracy.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권12호
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• pp.771-777
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• 2000

This paper deals with the design and fabrication of a novel superconducting power supply system, and characteristics have been investigated through experiments. Superconducting power supply consists of rotating and static parts, and superconducting magnet. In this experiment, superconducting foils were placed in parallel within the static part of the machine, pumping currents were measured with respect to rotor speeds and excitation currents. In addition, in order to observe the rotating flux distribution in the superconducting foils, several hall-sensors were placed in it. With the flux distribution acquired, effect of the flux on the superconducting foil during the process of current pumping has been discussed. Also, the general operational characteristics of the superconducting power supply system have been investigated on the basis of the current and voltage data, and magnetic field values acquired through the experiments.

• 센서학회지
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• 제14권4호
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• pp.244-249
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• 2005

In this study, radiation sensor tips are fabricated for remote sensing of X or gamma ray with inorganic scintillators and plastic optical fiber. The visible range of light from the inorganic scintillator that is generated by radiation source is guided by the plastic optical fiber and is measured by optical detector and power-meter. Two kinds of sensor tips are designed and fabricated such as film type and powder type. Many kinds of inorganic scintillators are used to fabricate both sensor tips, and the different wavelength of emitting lights from them are measured to determine the optimal inorganic scintillator which has maximum light output. As a radiation source X-ray generator and Ir-192 are selected to test a performance of sensor tip. It is expected that the fiber-optic radiation sensor is widely used in nuclear industry and medical applications due to its special characteristics such as good flexibility, easy in processing, long lengths and no interference to electro magnetic field.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.337-339
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• 1998

This paper deals with the design and fabrication of a novel superconducting power supply system, and characteristics have been analyzed through experiments. Superconducting power supply consists of rotating and static parts, and superconducting magnet. In this experiment, the current-pumping characteristics have been analyzed with superconducting sheets placed in parallel within the static part of the machine. In addition, in order to observe the 3-dimensional flux distribution in the superconducting sheet, several hall-sensors were placed in it. With the flux distribution acquired, the effect of the flux on the superconducting sheet during the process of current pumping have been analyzed. Also, general operational characteristics of the superconducting power supply system have been investigated on the basis of the current and voltage data and magnetic field values acquired through the experiments. In this experiment, maximum pumping current has been achieved to about 1280 amps.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.244-246
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• 1999

This paper deals with the design and fabrication of a novel superconducting power supply system, and characteristics have been analyzed through experiments. Superconducting power supply consists of rotating and static parts, and superconducting magnet. In this experiment, the current pumping characteristics have been analyzed with superconducting sheets placed in parallel within the static part of the machine. In addition, in order to observe the rotating flux distribution in the superconducting sheet, several hall-sensors were placed in it. With the flux distribution acquired, the effect of the flux on the superconducting sheet during the process of current pumping have been analyzed. Also, general operational characteristics of the superconducting power supply system have been investigated on the basis of the current and voltage data, and magnetic field values acquired through the experiments.

• 한국정밀공학회지
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• 제31권3호
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• pp.223-232
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• 2014

An inductive sensor system is proposed to detect the gear location and angular position of a geared shaft for automatic feeding of the shaft into the proper cutting position of the other end. The system consists of two set of coils, bridge circuit, signal condition circuit, and microprocessor. The coil sensors of the system measure changes of inductance along with the surface position of a geared shaft. The inductance changes are transformed to voltages by the bridge circuit, which are then conditioned and processed for the recognition of the gear. In order to incorporate with the experimental results with the sensor system, a finite element method (FEM) simulation for the magnetic field between the sensor and the shaft was carried out. The predicted results and the experiments revealed that the sensor system was appropriate for sensing the position of gear and the angular position of gear tooth of a geared shaft.

• Applied Microscopy
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• 제50권
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• pp.25.1-25.11
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• 2020

Scanning acoustic microscopy (SAM) or Acoustic Micro Imaging (AMI) is a powerful, non-destructive technique that can detect hidden defects in elastic and biological samples as well as non-transparent hard materials. By monitoring the internal features of a sample in three-dimensional integration, this technique can efficiently find physical defects such as cracks, voids, and delamination with high sensitivity. In recent years, advanced techniques such as ultrasound impedance microscopy, ultrasound speed microscopy, and scanning acoustic gigahertz microscopy have been developed for applications in industries and in the medical field to provide additional information on the internal stress, viscoelastic, and anisotropic, or nonlinear properties. X-ray, magnetic resonance, and infrared techniques are the other competitive and widely used methods. However, they have their own advantages and limitations owing to their inherent properties such as different light sources and sensors. This paper provides an overview of the principle of SAM and presents a few results to demonstrate the applications of modern acoustic imaging technology. A variety of inspection modes, such as vertical, horizontal, and diagonal cross-sections have been presented by employing the focus pathway and image reconstruction algorithm. Images have been reconstructed from the reflected echoes resulting from the change in the acoustic impedance at the interface of the material layers or defects. The results described in this paper indicate that the novel acoustic technology can expand the scope of SAM as a versatile diagnostic tool requiring less time and having a high efficiency.