• 비파괴검사학회지
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• 제36권3호
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• pp.217-224
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• 2016

콘크리트는 건축물에 가장 많이 사용되는 재료 중 하나이다. 건축물 시공 시 적절한 하중 재하시점을 결정하기 위해 콘크리트의 경화 상태의 점검은 매우 중요한 사항이다. 또한 부정확한 경화 모니터링은 건축물의 부실공사 혹은 붕괴로 이어질 수 있다. 본 연구에서는 어드미턴스를 기반으로 한 압전체 센서 자가진단기법을 확장 적용한 콘크리트 경화 모니터링 기법을 개발하였다. 이 기법을 통해 콘크리트의 경화를 모니터링 하였으며 실험 결과 분석을 통해 본 기법의 상대강도 추정 가능성을 확인하였다. 또한 경화 시 발현강도에 따른 어드미턴스 신호 예측을 위해 수치적 모델링을 하였으며 실험 결과와 경화 진행 경향성을 비교하였다. 이를 통해 본 연구에서 개발한 기법의 효용성을 실험 및 수치적으로 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1468-1473
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• 2013

This paper dealt with the propagation characteristics of acoustic signals produced by partial discharges and the positioning of PD origin in insulation oil to develop insulation diagnostic techniques of oil-immerged transformers. Electrode systems such as needle to plane, plane to plane, and particle electrodes were fabricated to simulate some defects of power transformers. In addition, the frequency spectrum and propagation characteristics of acoustic signals with partial discharge (PD) in insulation oil were analyzed. Although there were differences based on the type of defect, the frequency spectra of the acoustic signals measured by wide and narrow band acoustic emission (AE) sensors were distributed in the range of 50 kHz-400 kHz. Therefore, a narrowband AE sensor is suitable for the diagnosis of oil-immersed power transformers. We could find the position of the PD source with an error margin of 10% in the experiments by calculating the position of the PD occurrence using the time difference of arrival measured by five AE sensors.

• 대한한의진단학회지
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• 제12권2호
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• pp.8-17
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• 2008

Objectives: For the traditional pulse diagnosis in Oriental Medicine, not only the pulse shape in time domain, but the width, length and depth of arterial pulse also should be measured. However, conventional pulse diagnostic systems have failed to measure the spatial parameters of the arterial pulse e.g. effective length of arterial pulse in the wrist. In fact, there are many ways to measure that kind of spatial features in arterial pulsation, but among them, the method using image sensor provides relatively cheap and simple way, therefore I tested feasibility of measuring 2-dimensional pressure distribution by imaging devices. Methods: Using widely used PC cameras and dotted balloons, the subtle oscillation of skin over the radial artery was recorded continuously, and then the displacement of every dot was calculated. Consequently, the time course of that displacements shows arterial pulse wave. Results: By the proposed method I could get pressure distribution map with 30Hz sampling rate, 21steps quantization resolution, and approximately 1mm spatial resolution. With reduced quantization resolution, $3cm{\times}4cm$ view angle could be achieved. Conclusion: Although this method has some limitations, it would be useful method for detecting 2-dimensional features of arterial pulse, and accordingly, this method provides a novel way to detect 'narrow pulse', 'wide pulse', 'long pulse', 'short pulse', and their derivatives.

• Imaging Science in Dentistry
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• 제44권2호
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• pp.155-160
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• 2014

Purpose: The purposes of this study were to develop a workstation computer that allowed intraoperative touchless control of diagnostic and surgical images by a surgeon, and to report the preliminary experience with the use of the system in a series of cases in which dental surgery was performed. Materials and Methods: A custom workstation with a new motion sensing input device (Leap Motion) was set up in order to use a natural user interface (NUI) to manipulate the imaging software by hand gestures. The system allowed intraoperative touchless control of the surgical images. Results: For the first time in the literature, an NUI system was used for a pilot study during 11 dental surgery procedures including tooth extractions, dental implant placements, and guided bone regeneration. No complications were reported. The system performed very well and was very useful. Conclusion: The proposed system fulfilled the objective of providing touchless access and control of the system of images and a three-dimensional surgical plan, thus allowing the maintenance of sterile conditions. The interaction between surgical staff, under sterile conditions, and computer equipment has been a key issue. The solution with an NUI with touchless control of the images seems to be closer to an ideal. The cost of the sensor system is quite low; this could facilitate its incorporation into the practice of routine dental surgery. This technology has enormous potential in dental surgery and other healthcare specialties.

• 천문학회보
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• 제42권2호
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• pp.66.3-66.3
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• 2017

Korea Astronomy and Space Science Institute (KASI) is developing a coronagraph in collaboration with National Aeronautics and Space Administration (NASA) which will be installed on the International Space Station (ISS). The coronagraph can measure speed and temperature by using four filters approximately 400 nm and polarization filter in three different angles, differently with older coronagraphs. For the successful mission, it has development and experiment progress in three phases; total solar eclipse experiment in 2017, balloon experiment in 2019, and the ISS installation in 2021. As a first experiment, we developed a coronagraph without an occulter named with Diagnostic Coronagraph Experiment (DICE) for experiment for filter system and imaging sensor. We designed optics with a field of view from 2.5 to 15 solar radii. It has four filters approximately 400 nm and polarizer to measure speed and velocity of the solar corona. For the selection of filter or polarization angle, it has two mechanism parts; filter wheel assembly and a polarizer wheel assembly. Especially we used Core Flight System (CFS) platform which was developed by NASA, when we develop the coronagraph operation software. It provides us stability, reusability, and compatibility.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.27-37
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• 1997

Internal combustion engine is the main source of environmental pollutants and therefore better technology is required to reduce harmful elements from the exhaust gases all over the world. Especially, harmful elements from the exhaust gases are caused by incomplete combustion of mixture inside the engine cylinder and this abnormal combustion like misfire or partial burning is the direct cause of the air pollution and engine performance degradation. the object of this research is to detect abnormal combustion like misfire and to keep the engine performance in the optimal operating state. Development of a new system therefore could be applied to a real car. To realize this, the spark-plug in a conventional ignition system is used as a misfire detection sensor and breakdown voltage is analyzed. In this research, bias voltage(about 3kV) was applied to the electrodes of spark-plug and breakdown voltage signal is obtained. This breakdown voltage signal is analyzed and found that a combustion phenomena in engine cylinder has close relationship with harmonic coefficient K which was introduced in this research. Newly developed combustion diagnostic method( breakdown voltage signal analysis) from this research can be used for the combustion diagnostic and combustion control system in an real car.

• 대한예방한의학회지
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• 제26권2호
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• pp.25-35
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• 2022

Objectives : This study aims to analyze the patents filed in the clinical diagnosis sector where technologies have been actively developed since the advent of the 4th industrial revolution. Methods : The analysis has been conducted in two ways - the period from 2016 to 2021 and the time points before and after COVID-19 - by visualizing based on the word cloud method. Results : Over two thirds of patents has been filed in the A61B sector (71.8%) and cure, sensor, self diagnosis, control, and breakdown have been observed in the period above. During the overall period (2016~2021), 'ultrasound'(7.5%), 'image'(5.1%), 'skin'(4.0%), 'treatment'(3.4%), and 'artificial intelligence(2.5%)' were the frequently patent applications technologies. In addition, 'ultrasound'(6.2%), 'image'(5.5%), 'skin'(4.0%), 'treatment' (3.7%), and 'portable'(1.7%) appeared most frequently before COVID-19 whereas 'ultrasound(5.5%)', 'artificial intelligence(4.2%)', 'diagnostic device'(1.9%), 'dimentia'(1.6%), and 'diagnostic kit'(1.4%) emerged the most after COVID-19. Conclusion : This study is meaningful in that it showed the technological development trend in the digital diagnosis sector and it was found that the Korean medicine field should contribute to this field more actively in the future.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.53-58
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• 2023

The storage capacity of 3D-NAND flash memory has been enhanced by the multi-layer dielectrics. The deposition process has become more challenging due to the tight process margin and the demand for accurate process control. To reduce product costs and ensure successful processes, process diagnosis techniques incorporating artificial intelligence (AI) have been adopted in semiconductor manufacturing. Recently there is a growing interest in process diagnosis, and numerous studies have been conducted in this field. For higher model accuracy, various process and sensor data are required, such as optical emission spectroscopy (OES), quadrupole mass spectrometer (QMS), and equipment control state. Among them, OES is usually used for plasma diagnostic. However, OES data can be distorted by viewport contamination, leading to misunderstandings in plasma diagnosis. This issue is particularly emphasized in multi-dielectric deposition processes, such as oxide and nitride (ON) stack. Thus, it is crucial to understand the potential misunderstandings related to OES data distortion due to viewport contamination. This paper explores the potential for misunderstanding OES data due to data distortion in the ON stack process. It suggests the possibility of excessively evaluating process drift through comparisons with a QMS. This understanding can be utilized to develop diagnostic models and identify the effects of viewport contamination in ON stack processes.

• 한국산학기술학회논문지
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• 제15권1호
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• pp.441-448
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• 2014

USN(Ubiquitous Sensor Network) 응용 소프트웨어는 다양한 대상 운영체제의 핵심모듈들을 기반으로, 다양한 종류의 센서 노드들을 유기적으로 제어하는 복잡한 특징을 가진다. 이에 따라, 현재 USN 응용 분야에서는 효율적으로 소프트웨어를 개발하기 위한 다양한 연구가 진행되고 있다. 본 논문에서는 센서 네트워크 환경에서 하나의 모델로 부터 여러 플랫폼에 맞는 노드 소프트웨어를 효율적으로 개발하기 위한 속성 기반 개발을 지원하는 속성 설계 기법을 제시한다. 제시된 기법에서는 Platform Independent Model과 Platform Specific Model을 만들기 위한 속성을 설계하는 방법을 기술한다. 본 논문에서 제시하는 기법을 사용하면, 속성 값의 선택을 통하여 멀티 플랫폼을 위한 노드 소프트웨어를 손쉽게 디자인함으로써 소프트웨어 개발 생산성은 증대된다. 또한 운영체제의 변화에 따라 속성 변경을 통하여 노드 소프트웨어를 쉽게 재생성할 수 있으므로, 소프트웨어의 유지보수성이 향상된다.

• 디지털콘텐츠학회 논문지
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• 제9권4호
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• pp.601-606
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• 2008

U-Healthcare는 센서네트워크분야에서 가장 중요한 응용 분야중 하나이다. 응급상황에 대한 대처가 필요한 다양한 계층의 사람들에게 있어 매우 중요한 서비스가 될 수 있다. 본 논문에서는 자신의 맥정보를 베이스스테이션(Base Station)을 통해 응급상황에 대한 정보를 제공하고 동시에 원격지에 있는 보호자에게 제공하고, 의료진에게 전송하여 정확한 진단을 지원하는 시스템에 대해 설명한다. 이를 위해 맥진모듈로부터 취득된 맥진정보를 베이스스테이션 및 모니터링 시스템으로 Zigbee 및 TCP/IP를 통해 전송하며 이에 사용되는 패킷구조를 설계한다. 또한 모니터링 시스템에서는 전송되는 맥진정보를 데이터베이스에 저장하고 웹을 통해 서비스를 제공함으로써 가족을 포함하여 인가된 사람들로 하여금 맥의 상태를 모니터링하는 시스템을 설계하고 구현한다.