• Archives of Plastic Surgery
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• 제48권4호
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• pp.389-391
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• 2021

Solo hand surgery is becoming increasingly common, mostly due to a lack of assistants and dedicated operating theatres. The solo hand surgeon faces challenges of proper hand positioning, elevation, and skin flap/tissue retraction. Most commercially available hand retractors or stands do not address all the relevant problems and are not economically feasible for trainee surgeons. The Jain's hand retractor system and stand, described herein, provides solutions to all these problems, and its simple design helps surgeons to reproduce it easily.

• International Journal of Precision Engineering and Manufacturing
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• 제9권3호
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• pp.51-54
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• 2008

A novel stereolithography method using evanescent light has been proposed as a means to realize 100-nanometer resolution. An in-process measurement system with high accuracy has been introduced to the nanostereolithography apparatus. Specifically, an optical microscopic system was developed to monitor the exposure process and a confocal positioning system was established to improve the longitudinal positioning accuracy in the layer-by-layer process. A high-power objective lens, a tube lens, and a charge coupled device (CCD) were included in the optical microscopic system, whereas a laser, a high-power objective lens, a piezoelectric (PZT) stage, a condenser lens, a pinhole, and a photomultiplier (PMT) made up the confocal microscopic system. Two verification experiments were conducted, and the results indicated that the optical microscopic system had a horizontal resolution of 200 nm and that the confocal positioning system provided a depth resolution of 30.8 nm. These results indicate that nanostereolithography can be successfully performed with this system.

• 한국위성정보통신학회논문지
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• 제5권2호
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• pp.69-74
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• 2010

본 논문에서는 LED 조명 기반의 실내 측위 시스템을 제안하였다. LED가 빛을 방출하며 고속의 switching이 가능하다는 반도체 조명이라는 특징을 이용하여 각각의 LED 조명에 고유의 8 비트 ID를 부여 후, 이를 방출되는 조명 빛에 변조하여 보내주었다. 수신기는 16 개의 LED 조명으로부터 조합된 정보를 수신하게 되고, 수신된 정보와 각각의 ID 정보 간의 correlation coefficient를 이용하여 $4\;m\;{\times}\;4\;m\;{\times}\;2\;m$의 공간에서 100 cm 및 50 cm resolution을 가지는 위치인식 시스템을 시뮬레이션을 통해 구현하여 보았다. 제안된 측위 시스템은 간단한 알고리즘을 사용하였고, LED 조명 인프라를 사용하여 구축함으로써 설치비용 절감이 가능할 것이라 기대된다.

• 제어로봇시스템학회논문지
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• 제14권6호
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• pp.608-614
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• 2008

This paper describes a location tracking system to guide landing process of an Unmanned Helicopter(UMH) exploiting MIT Cricket nodes. For automatic landing of a UMH, a precise positioning system is indispensable. However, GPS(Global Positioning System) is inadequate for tracking the three dimensional position of a UMH because of large positioning errors. The Cricket systems use Time-Difference-of-Arrival(TDoA) method with ultrasonic and RF(Radio Frequency) signals to measure distances. They operate in passive mode in that a listener attached to a moving device receives distance signals from several beacons located at fixed points on ground. Inevitably, this passive type of implementation causes large disturbances in measuring distances between beacons and the listener due to wind blow from propeller and turbulence of UMH body. To cope with this problem, we proposed active type of implementation for positioning a UMH. In this implementation, a beacon is set up at UMH body and four listeners are located at ground area at least where the UMH will land. A pair of Ultrasonic and RF signals from the beacon arrives at several listeners to calculate the position of the UMH. The distance signals among listeners are synchronized with a counter value appended to each distance signals from the beacon.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.643-644
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• 2018

최근 실내 위치 추적시스템과 실외 위치 추적시스템은 다른 방식으로 운영되고 있다. 실내 측위 기법으로는 WiFi와 BLE beacon을 이용한 측위를 이용하고, 실외 측위는 GPS와 PDR을 이용한다. 본 논문에서는 이를 혼용하여 위치를 측정하기 위한 기기로 모바일기기 대표적으로 스마트폰을 기반으로 측정할 때, 실내인지 실외인지를 확인하여 실내에서 운영되는 기법을 이용하다가 실외로 이동할 때 GPS로 자동으로 변환 시켜주는 방식이 필요하다. 실내에서 GPS를 이용하였을 경우 층이나 공간의 구분이 어렵다. 이를 해결하기 위한 방식을 제안한다.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2177-2184
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• 2012

실내 위치인식 방법은 GPS 기반의 실외 위치인식 방법과 비교하여 보다 높은 정확도를 요구하며 그 중요성 또한 증가하고 있다. FingerPrint 위치인식 방법은 데이터베이스에 참조변수의 수신신호패턴을 미리 저장하고, 단말기의 실시간 측정 신호를 매칭시킴으로써 단말의 위치를 추정하는 뛰어난 실내 위치인식 방법이다. FingerPrint 위치인식 방법에서는 정확한 데이터베이스 구축이 요구되지만 여러 가지 요인에 의하여 오차가 발생할 수 있다. 본 연구에서는 접근 지점의 연결여부에 따른 각 단말기의 수신신호 패턴을 분석하여, 접근 지점의 연결 여부에 따른 오차가 FingerPrint DB 구성의 중요한 오차 요인이 될 수 있음을 실험을 통하여 밝힌다.

• 한국컴퓨터정보학회논문지
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• 제27권12호
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• pp.231-238
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• 2022

무선 통신의 발전과 IoT 센서의 발전으로 인해 휴대용 모바일 통신 장치와 센서 간의 근거리 무선 통신 기술들이 개발되어 다양한 응용서비스를 제공하는 고부가가치의 플랫폼으로 발전하고 있다. 본 논문에서는 비콘, 블루투스, UWB(Ultra-wideband), ZigBee, NFC(Near Field Communication), Z-Wave, 6LoWPAN(IPv6 over Low power WPAN), D2D(Device to Device) 등과 같은 근거리 무선 통신 기술 중에서, 실내 위치 측위를 제공할 수 있는 비콘을 기반으로 IoT 서비스 플랫폼을 제안하였다. 그리고 무분별한 비콘 스팸 신호를 차단하고 유연성과 확장성을 가진 REST 웹 서비스 기술을 적용하여 비콘 연동 웹서버를 설계하였다. 데이터 전송 성공률, 비콘 Push 차단 성공률, 위치 측위 정확도, IoT 연동 처리 성공률, REST 웹 서비스 기반 데이터 처리 성공률 등을 테스트하여 다른 기종 간의 데이터 접근성을 검증하였다. 설계된 IoT 서비스 플랫폼을 통해 향후 근거리 무선 통신 기반의 비즈니스 모델과 서비스 플랫폼에 대한 다양한 제안과 연구가 진행될 것이다.

• 한국기계가공학회지
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• 제12권1호
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• pp.97-103
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• 2013

A new precision positioning mechanism for stage was been developed by Displacement Magnification Device(DMD) in this paper. The DMD was composed of the beam and multilayer piezoelectric actuators. The theoretical and experimental analysis of DMD to enlarge displacement more then 50times were discussed. And the 2-axis stage by using displacement amplification apparatus was added in the new DMD, and it was able to do it through finite element analysis and experiment. As the results, the magnification of DMD can be obtained about $100{mu}m$ displacement to the 10V input voltage($1.5{mu}m$). And the about 50nm of linearity error in the $30{mu}m$ measurement range and 20times of the amplification in displacement can be measured. In addition, the experimental results are confirmed the possibility of millimeter displacement characteristics and correspond to finite element analysis results.

• Journal of Biosystems Engineering
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• 제22권4호
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• pp.411-420
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• 1997

The mechanization efficiency using high ability machines such as tractors or combines in a paddy field rice farm is high. Mechanization in harvesting fruits and vegetables is difficult, because they are easy to be damaged. Therefore, Advanced techniques for careful handling fruits and vegetables are necessary in automation and robotization. An apple harvesting robot must have a recognition device to detect the positioning of fruit, manipulators which function like human arms, and hand to take off the fruit. This study is related to the development of a rotatic hand as the first stage in developing the apple harvesting robot. The results are summarized as follows. 1. It was found that a hand that was eccentric in rotatory motion, was better than a hand of semicircular up-and-down motion in harvesting efficiency. 2. The hand was developed to control changes in grasp forces by using tape-type switch sensor which was attatched to fingers' inside. 3. Initial finger positioning was set up to control accurate harvesting by using a tow step fingering position. 4. This study showed the possibility of apple harvesting using the developed robot hand.

• 대한공간정보학회지
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• 제24권2호
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• pp.37-46
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• 2016

The difference between definition time of GPS (Global Positioning System) position data and actual display time of car positions on a map could reduce the accuracy of car positions displayed in PND (Portable Navigation Device)-type CNS (Car Navigation System). Due to the time difference, the position of the car displayed on the map is not its current position, so an improved method to fix these problems is required. It is expected that a method that uses predicted future positionsto compensate for the delay caused by processing and display of the received GPS signals could mitigate these problems. Therefore, in this study an analysis was conducted to correct late processing problems of map positions by mapmatching using a Kalman filter with only GPS position data and a RRF (Road Reduction Filter) technique in a light-weight CNS. The effects on routing services are examined by analyzing differences that are decomposed into along and across the road elements relative to the direction of advancing car. The results indicate that it is possible to improve the positional accuracy in the along-the-road direction of a light-weight CNS device that uses only GPS position data, by applying a Kalman filter and RRF.