• 제목/요약/키워드: Non-contact method

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간접접촉 심전도 측정용 전극의 주파수 특성 (Frequency Response of the electrode for Indirect-contact ECG)

  • 임용규
    • 대한의용생체공학회:의공학회지
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    • 제29권3호
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    • pp.249-253
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    • 2008
  • The indirect-contact ECG (IDC-ECG) was introduced by a prior study for daily non-intrusive measurements. To improve the signal quality and to extend the application area of IDC-ECG, close study of the frequency characteristics of the IDC-ECG is necessary. In this study, the frequency response of the active electrode for several sample clothes was measured under conditions of actual IDC-ECG measurement with human body. Higher gain in low frequency range than expected by prior study was observed. In addition to it, wide variation in gain according to the cloth type in the low frequency range was observed. Variation in gain caused by moisture variation in the clothes was also observed. This study shows that the parallel R-C connection is proper for electrode model and the resistive factor is influenced by moisture in the clothes. This study is the first that provides the frequency response of the electrode in the actual indirect-contact ECG measurement and it is expected that the results will be helpful to improve the indirect-contact ECG method.

비접촉형 마그넷기어를 적용한 클린 반송장치의 개발 (Development of Non-Contact Conveyor for Clean Process by Applying Magnet Gears)

  • 오영진;노태정
    • 한국산학기술학회논문지
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    • 제11권10호
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    • pp.3633-3640
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    • 2010
  • 헬리컬형으로 자화된 영구자석을 이용한 비접촉 마그넷 기어를 개발하기 위하여 3차원 FEM 해석 기법을 활용하였고 마그넷 기어의 자기적 특성 해석 및 설계 요소기술을 확보하였다. 마그넷 기어를 이용한 클린 반송 컨베이어 및 회전장치의 성능평가를 위하여 class 10의 클린부스 환경에서 시험운전을 거쳐, 이송 속도, 최대 허용 토크, 클린도, 최대 이송 중량, 헌팅 유무, 소음도 등을 측정한 결과 클린도 class 10의 공정까지도 대응이 가능한 것으로 확인되었다.

레이저 유도 플라즈마 분광 기법을 이용한 용접 연강에서의 비접촉 강도 측정과 해석 (Non-contact Measurement and Analysis of Surface Hardness on Welding Steel using Laser-induced Breakdown Spectroscopy)

  • 김주한;고찬솔
    • 한국정밀공학회지
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    • 제31권2호
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    • pp.141-148
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    • 2014
  • In this work, effects of plasma on different hardness of welding steel using laser-induced breakdown spectroscopy were investigated. The ratios of ionic to atomic spectrum peaks were related to its material hardness. The major spectrum peak (Fe) and minor spectrum peak (Mn) were considered as monitoring elements. The stronger repulse plasma was generated, the harder material it was. The ratios of ionic to atomic spectrum peaks increased with respect to the material hardness as well. The correlation of minor spectrum peaks was stronger than that of major spectrum peaks. However, the major spectrum peaks indicated a similar trend, which could be used to estimate the hardness, too. Based on this result, the method could be used as a non-contact remote measurement of material properties.

비접촉식 표면연마를 통한 디버링 효과 향상에 관한 연구 (A Study on Improving Deburring Efficiency Using Non-Contact Finishing Process)

  • 이정희;곽재섭
    • 한국기계가공학회지
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    • 제21권6호
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    • pp.74-80
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    • 2022
  • The surface status of a workpiece determines its functionality, product quality, and manufacturing costs. Thus, several finishing technologies have been widely investigated and applied to improve surface characteristics. In this study, rotational electro-magnetic abrasive finishing (REMAF) was suggested as a non-contact finishing process to achieve high geometric precision. To verify the effects of the REMAF process on burr removal on the surface of Al6061, experiments were conducted using the Taguchi method. Based on the experimental results analyzed by the S/N ratio and ANOVA, the optimal conditions were defined as A3B2C3D3 that corresponded to 1,800 rpm of rotational speed, 1.5 kg of abrasive particle weight, 0.7 mm of abrasive diameter, and 15 min of working time. In addition, the particle weight was a key attribute for deburring, whereas the working time was less effective.

비접촉형 심박수 측정 정확도 향상을 위한 인공지능 기반 CW 레이더 신호처리 (Artificial Intelligence-Based CW Radar Signal Processing Method for Improving Non-contact Heart Rate Measurement)

  • 윤원열;권남규
    • 대한임베디드공학회논문지
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    • 제18권6호
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    • pp.277-283
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    • 2023
  • Vital signals provide essential information regarding the health status of individuals, thereby contributing to health management and medical research. Present monitoring methods, such as ECGs (Electrocardiograms) and smartwatches, demand proximity and fixed postures, which limit their applicability. To address this, Non-contact vital signal measurement methods, such as CW (Continuous-Wave) radar, have emerged as a solution. However, unwanted signal components and a stepwise processing approach lead to errors and limitations in heart rate detection. To overcome these issues, this study introduces an integrated neural network approach that combines noise removal, demodulation, and dominant-frequency detection into a unified process. The neural network employed for signal processing in this research adopts a MLP (Multi-Layer Perceptron) architecture, which analyzes the in-phase and quadrature signals collected within a specified time window, using two distinct input layers. The training of the neural network utilizes CW radar signals and reference heart rates obtained from the ECG. In the experimental evaluation, networks trained on different datasets were compared, and their performance was assessed based on loss and frequency accuracy. The proposed methodology exhibits substantial potential for achieving precise vital signals through non-contact measurements, effectively mitigating the limitations of existing methodologies.

상황 인식 기반 다중 영역 분류기 비접촉 인터페이스기술 개발 (Technology Development for Non-Contact Interface of Multi-Region Classifier based on Context-Aware)

  • 김송국;이필규
    • 한국인터넷방송통신학회논문지
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    • 제20권6호
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    • pp.175-182
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    • 2020
  • 비접촉식 시선추적 기술은 인간과 컴퓨터간의 인터페이스로서 장애가 있는 사람들에게 핸즈프리 통신을 제공하며, 최근 코로나 바이러스 등으로 인한 비접촉시스템에도 중요한 역할을 할 것으로 기대된다. 따라서 본 논문에서는 인간 중심의 상호 작용을 위한 상황인식 다중영역 분류기 및 ASSL 알고리즘을 기반으로 한 사용자 인터페이스 기술을 개발한다. 이전의 AdaBoost 알고리즘은 안구 특징 사이의 공간적 맥락 관계를 이용할 수 없기 때문에 눈의 커서 포인팅 추정을 위한 안면 추적에서 충분히 신뢰할 수 있는 성능을 제공 할 수 없다. 따라서 본 논문에서는 효율적인 비접촉식 시선 추적 및 마우스 구현을 위한 눈 영역의 상황기반 AdaBoost 다중 영역 분류기를 제시한다. 제안된 방식은 여러 시선 기능을 감지, 추적 및 집계하여 시선을 평가하고 온 스크린 커서 기반의 능동 및 반 감독 학습을 조정한다. 이는 눈 위치에 성공적으로 사용되었으며 눈 특징을 감지하고 추적하는 데에도 사용할 수 있다. 사용자의 시선을 따라 컴퓨터 커서를 제어하며 칼만 필터를 이용하여 실시간으로 추적하며, 가우시안 모델링을 적용함으로써 후처리하였다. Fits law에 의해 실험하였으며, 랜덤하게 대상객체를 생성하여 실시간으로 시선추적성능을 분석하였다. 제안하는 상황인식을 기반 인식기를 통하여 비접촉 인터페이스로서의 활용이 높아질 것이다.

복합소재 O-링의 압축변형 특성에 관한 연구 (A Study on the Compression Characteristics of Bi-polymer O-rings)

  • 김도현;김청균
    • Tribology and Lubricants
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    • 제21권4호
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    • pp.171-176
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    • 2005
  • O-ring seal is an essential component in various mechanical apparatuses for a sealing of oil container and pressure vessels. This paper presents the sealing pressure and compressive contact behaviors of hi-polymer O-rings, which is made by an outer shell of FFKM material and an inner solid ring of FKM one. The contact normal pressure and its ratios are measured by experimental method with an automatic control system of the working temperature and analyzed numerically by using the non-linear Marc FEM program. The results show reasonably good agreements between the computed FEM results and measured ones when the operating temperature is kom normal temperature of $18^{\circ}C$ and a high temperature of $300^{\circ}C$ But the compared values between the computed and tested results show a little difference because of the increased temperature, which is related to the non-linear parameter of the O-ring material. Bi-polymer 0-ring shows a good contact normal stress and compression behavior for a given operation temperature and compression ratio.

하드 디스크 드라이브 동작 상태 충격 시에 램프 충돌 유무에 따른 디스크와 슬라이더의 거동해석 (Analysis of dynamic characteristics between disk and slider with operational shock in hard disk drive)

  • 김민재;임건엽;박경수;박노철;박영필
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2014년도 추계학술대회 논문집
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    • pp.975-977
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    • 2014
  • Recently, As portability of storage device has been increased, it is important to analyze the precise anti-shock analysis. For non-operational shock analysis, the accuracy of non-operational shock simulation has been improved. However, because operational shock analysis includes nonlinear process, it is hard to get clear result from operational shock simulation. In this paper, by using Lagrange multiplier method, the FE model including ramp-disk contact of nonlinear process will be analyzed. Through this, we find ramp-disk contact affect the dynamic of slider. Additionally, for the more accurate analysis, we should include ramp-disk contact process at the FE model.

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유연도 영향계수법을 이용한 접촉 결합부의 모델링 (Finite Element Modeling of Contact Joints by Flexibility Influence Coefficient)

  • 오제택;조성욱;이규봉
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.814-819
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    • 2003
  • Machine tool design concepts have evolved towards high efficiency, accurate precision. high structural integrity, and multi-functional systems. Like many other structures, machine tools are also composed of many parts. When these parts are assembled, many kinds of joints are used. In the finite element analysis of these assembled structures, most joints are commonly considered as rigid joints. But, to get the more accurate solution, we need to model these joints in a appropriate manner. In this study, rational dynamic modeling and analysis method for complex structures are studied with special attention to slide way joints. For modeling of slide way joints, a general modeling technique is used by influence coefficients method which is applied to the conversion of detailed finite element model to the equivalent reduced joint model. The theoretical part of this method is illustrated and the method is applied to the structure with slide way joint. In this method. the non-linearity of the contact surfaces is considered within a proper range and the boundary effect of the joint model can be eliminated. The proposed method was applied to finite element modal analysis of a clamp jointed cantilever beam and slide way joints of the vertical type lathe. The method can also be used to other kinds of joint modeling. The results of these analysis were compared with those of Yoshimura models and rigid joint models. which demonstrated the practical applicability of the proposed method.

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Investigating the effect of using three pozzolans (including the nanoadditive) in combination on the formation and development of cracks in concretes using non-contact measurement method

  • Grzegorz Ludwik Golewski
    • Advances in nano research
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    • 제16권3호
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    • pp.217-229
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    • 2024
  • This paper presents results of visual analysis of cracks formation and propagation of concretes made of quaternary binders (QBC). A composition of the two most commonly used mineral additives, i.e. fly ash (FA) and silica fume (SF) in combination with nanosilica (nS), has been proposed as a partial replacement of the cement. The principal objective of the present study is to achieve information about the effect of simultaneous incorporation of three pozzolans as partial replacement to the OPC on the fracture processes in concretes made from quaternary binders (QBC). The modern and precise non-contact measurement method (NCMM) via digital image correlation (DIC) technique was used, during the studies. In the course of experiments it was established that the substitution of OPC with three pozzolans including the nanoadditive in FA+SF+nS FA+SF+nS combination causes a clear change of brittleness and behavior during fractures in QBCs. It was found that the shape of cracks in unmodified concrete was quasi-linear. Substitution of the binder by SCMs resulted in a slight heterogeneity of the structure of the QBC, including only SF and nS, and clear heterogeneity for concretes with the FA additive. In addition, as content of FA rises throughout each of QBC series, material becomes more ductile and shows less brittle failure. It means that an increase in the FA content in the concrete mix causes a significant change in fracture process in this composite in comparison to concrete with the addition of silica modifiers only.