• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.613-617
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• 2001

The test items like as endurance, air leakage and oil endurance test is requested for reliability evaluation about O-ring which is a kind of core machinery accessories of semi-conduct manufacturing equipment. For verification of these, we design and manufactured a test system for endurance, air leakage and oil endurance of O-ring for semi-conduct manufacturing equipment, and also performed the test for two kinds of O-ring, as it were Viton and Kalretz. The characteristics of this test equipment consist in realization of the test conditions of semi-conduct manufacturing equipment and satisfying the test method. The test conditions are cut gas, vacuum grade, temperature and revolution numbers in the endurance test system, vacuum grade and temperature in the air leakage test system, temperature and time in the oil endurance test system. The separating test results for wearing which is an oil endurance test item, the wearing index of domestic produced Viton O-ring is higher than foreign product by 2%, wearing rate of Kalretz O-ring better than Viton O-ring by 17%, and particles existed in various place. The test result of air leakage which is measured through the RGA sensor used Helium, the vacuum grade was $10^-3$Torr. And the test result of oil endurance, the volume change rate was 7~15%. Hereafter, we intend to analysis the reliability test evaluation and to utilize for domestic manufacturing companies by establishing data base and developing reliability softwares.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.90-94
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• 1995

In this paper, we improved the O-Ring Measurement System(O-R MS) based on oriental constitutional theory of four classes for objectify constitutional diagnosis by O-Ring test method which is one of effective methods in several constitutional diagnosis. The result of using in a half of year, some problems are pointed out. To settle these problems, we improved the actuator, display module, sensor module, and hardware of controller. Also, the software is supplemented to using the more decision parameters. It is estimated to have a high practical use for the objectified constitutional diagnosis.

• 한국통신학회논문지
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• 제29권1C호
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• pp.45-49
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• 2004

본 논문은 수정된 이방성 확산 펄터를 이용한 영상 개선 방법을 제안하였다. 이를 위하여 최소 신뢰 스케일을 기반으로 하는 센서 잡음 추정과 스케일 스페이스 방법을 도입하였다. 이때 이방성 필터는 구해진 임계값 함수와 국부 기울기에 의해 수정되었다. 모의 실험을 통해 제안한 방법이 평탄 영역에서의 잡음을 거의 증폭시키지 않으면서도 뛰어난 에지 향상을 보임을 증명할 수 있었다.

• 오토저널
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• 제12권4호
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• pp.66-74
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• 1990

Friction between piston-ring assembly and cylinder wall of a spark ignition engine was evaluated under various engine operating conditions utilizing a grasshopper linkage system. The friction force was estimated by the force balance relation at the small end of connecting rod. Three forces were chosen to be measured for the objective. They were gas pressure inside the cylinder, inertia force of the piston-ring assembly, and the force exerted by the connecting rod. These forces were measured by a piezo type pressure sensor, an accelerometer and strain gauges, respectively. Comparisons were made with the frictional force evaluated by the conventional method where the assumption of constant rotational speed of engines was adopted. Due to the variation of rotational speed of engines, the conventional method was found to lead to a large error in the evaluation of the frictional force.

• 한국정보과학회논문지:정보통신
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• 제37권5호
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• pp.409-414
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• 2010

무선 센서 네트워크에서 센서노드의 지리적인 위치를 요구하는 응용들이 현저하게 증가하고 있다. 최근 다양한 위치 측위 알고리즘들이 제안 되었지만, 대부분의 알고리즘은 특정한 하드웨어로 얻은 RSSI와 LQI 측정치를 기반으로 위치를 추정하고 있다. 본 논문에서는 이러한 추가적인 정보를 이용하지 않아도 기존 연구와 근사한 측정 결과를 얻을 수 있는 '가중 다중 링을 이용한 측위' 알고리즘 WMRL(Weighted Multiple Rings Localization)을 제안한다. 고정노드(anchor nodes)들이 배치되어 있으며, 각 고정노드는 주기적으로 서로 다른 신호 세기의 비콘(beacon) 신호를 송출한다고 가정한다. 그러면, 비콘 신호는 공간상에 링을 형성하게 되며, 파워 레벨의 세기에 따라 다수의 동심원을 형성하는 동시에 링 간에 교차영역을 생성한다. 본 논문에서는 효율적인 측위 계산을 위해 각 링의 거리 비율에 따른 가중치 모텔을 제안한다. 또한, 센서노드는 수신이 가능한 고정노드로부터 가장 가까운 링을 발견할 수 있으며, 이를 활용하여 센서노드는 자신의 위치를 고정노드 좌표의 가중 합으로 구한다. 제안된 알고리즘은 분산적으로 위치를 계산할 수 있으며, 추가적인 하드웨어를 요구하지 않는다. 추가적으로, 비 신뢰적인 RSSI 및 LQI에 의존하지 않고, 각 링 간의 거리 비율로 측위가 가능한 것이 특정이다. 그럼에도 불구하고, WMRL은 시뮬레이션 결과 2개의 링, 즉 2개의 파워 레벨로 구성하였을 경우에는 기존의 centroid 방식보다 평균 측위 에러가 2배 감소하였고, 3개의 링을 구성하였을 경우에는 WCL(Weighted Centroid Localization)과 대등한 측위 결과를 보였다.

• 한국재난정보학회 논문집
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• 제5권1호
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• pp.122-139
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• 2009

USN Middleware plays roles of broker between sensors and applications. It collects sensor data, decides the situation and sends the result to the applications. It is not good to decide the situation from one sensor data, because it may error data or reflect small part of all. In this paper, we propose the disaster management model based on the concept 'group' and 'semantic information' from the sensing data. Group is the primary unit to decide the situation. It consists of several sensors which were installed in the same place and had the same pre-defined condition to act. For example, all fire sensors in the room simultaneously trigger the ring when the same pre-defined temperature is recorded. Then, the all fire sensors are included to the same one sensor group. All operations of the intelligent USN middleware are based on the 'group' unit. Disaster information is the result of the interpretation of the sensing data. based on the 'group', the disaster meaning is processed.

• 한국항행학회논문지
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• 제23권5호
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• pp.415-423
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• 2019

본 논문에서는 유전율 측정을 위한 구부러진 슬롯이 추가된 고감도 마이크로스트립 패치 센서 안테나의 설계 방법에 대하여 연구하였다. 유전율에 대한 감도를 향상시키기 위해 단일 링 CSRR 구조와 유사한 구부러진 슬롯이 패치의 한쪽 방사면에 추가되었다. 제안된 마이크로스트립 패치 센서 안테나의 감도를 기존의 직사각형 마이크로스트립 패치 센서 안테나와 얇은 직사각형 슬롯이 추가된 마이크로스트립 패치 센서 안테나와 비교하였다. 세 마이크로스트립 패치 센서 안테나는 피 시험 상판이 없는 상태에서 전송 계수가 2.5 GHz에서 공진하도록 0.76 mm 두께의 RF-35 기판 상에 설계하고 제작하였다. 피 시험 상판으로 비유전율이 2.17에서 10.2 범위에 있는 타코닉 기판 5종을 사용하여 실험한 결과, 입력 반사계수의 공진 주파수의 이동으로 측정된 제안된 마이크로스트립 센서 안테나의 감도는 기존의 직사각형 마이크로스트립 패치 센서 안테나와 비교할 때 4.1배에서 6.1배 증가하는 것을 확인하였다.

• 한국정밀공학회지
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• 제26권2호
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• pp.86-93
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• 2009

Elastomeric O-rings have been the most common seals due to their excellent sealing capacity, and availability in costs and sizes. One of the critical applications of O-ring seals is solid rocket motor joint seal where the operating hot gas must be sealed during the combustion. This has long been a design issue to avoid the system failure. For laterally constrained, squeezed and pressurized condition, deformed shape of O-ring was measured by computed tomography method and CCD laser sensor, compared with numerical calculations. As clearance gap changes, sealing performance had been evaluated on peak contact stresses at top, bottom and side contact surfaces. As clearance gap increases, peak contact stresses and contact widths in top and side contact surfaces increase, and the asymmetry of stress distributions is promoted due to pressure increase. It is suggested that peak stress of bottom contact surface can be approximated by simple superposition of peak ones due to squeeze and pressure. Under pressurized condition, sealing performance is dependent on not peak stresses of bottom and side contact surfaces but that of top.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1488-1490
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• 2008

The gyroscope is the sensor for detecting the rotation in inertial reference frame and constitute the navigation system together an accelerometer. As the inertial reference equipment for attitude determination and control in the satellite, the mechanical gyroscope has been used but it bring the disturbance for mass unbalance so the disturbance give a bad influence to the observation satellite mission because the mechanical gyroscope has the rotation parts. During the launch, The mechanical gyroscope is weak in vibration, shock and has the defect of narrow operating temperature range so it need the special design in integration. Recently the low orbit observation satellite for seeking the high pointing accuracy of image camera payload accept the FOG(Fiber Optic Gyro) or RLG(Ring Laser Gyro) for the attitude determination and control. The Ring Laser Gyro makes use of the Sanac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. It need the 1000V DC to create the He-Ne plasma in discharge tube. In this paper, the design process of the High Voltage Power Supply for RLG(Ring Laser Gyroscope) is described. The specification for High Voltage Power Supply(HVPS) is proposed. Also, The analysis of flyback converter topology is explained. The Design for the HVPS is composed of the inverter circuit, feedback control circuit, high frequency switching transformer design and voltage doubler circuit.

• 제어로봇시스템학회논문지
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• 제18권10호
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• pp.934-939
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• 2012

This paper proposes a new algorithm for ultrasonic sensors arranged on ring frame to identify obstacles surrounding itself by TOFs (time of flight). The ring frame has multiple channels consisting of a transmitter and a receiver. When the transmitter of a selected channel transmits ultrasonic signal, the TOFs of reflected signals from obstacles are acquired by the receiver of the channel. The process continues for all channels consecutively. Then, by using parabolic curve fitting of TOFs of all channel, the proposed algorithm not only calculates distances from multiple obstacles, but also identifies if the shape of obstacles are point or plane by the coefficients of the curve. By the experiment using 16 ultrasonic transceivers on the ring frame in the environment of two poles and two planes, we show the feasibility of the proposed scheme.