타 성분 영향을 고려한 요당과 요단백의 흡수분광학 진단

윤길원,김혜정,Yoon, Gil-Won,Kim, Hye-Jeong 한국광학회 2009 한국광학회지 Vol.20 No.6

요당과 요단백은 소변검사의 중요한 항목으로 스트립을 사용하는 화학적 방법에 의하여 측정되어왔다. 본 연구에서는 중적외선 분광학을 이용하여 이 두 성분의 농도를 측정하였다. 샘플은 상용 합성뇨를 사용하였으며 여기에 추가적으로 글루코즈와 알부민, 그리고 가장 큰 영향의 간섭물질인 적혈구의 세 성분의 농도를 서로 상관관계 없이 조절하여 만들었다. 부분최소자승회귀법을 바탕으로 각 성분의 농도 예측을 위한 최적 파장대역을 구하였다 (글루코즈 980 - 1150/cm, 알부민 1400 - 1570/cm). 다른 성분에의한 간섭은 예측오차를 증가시켰으며, 특히 알부민의 경우에는 글루코즈와 적혈구에 의한 영향이 크게 나타났다. 타 성분의 유무에 따라서 글루코즈 농도가 0 ${\sim}$ 1000 mg/dl인 범위에서의 예측오차는 29.85 ${\sim}$ 45.19 mg/dl 이며 알부민 경우에는 0 ${\sim}$ 500 mg/dl 범위에서 예측오차는 14.0 ${\sim}$ 93.11 mg/dl 이였다. 본 연구는 몇 단계의 범위만을 제시하는 스트립을 이용한 기존의 요검사 보다 더욱 정량적 평가가 가능한 대안으로 사료되었다. Glucose and protein in urine are among the important substances for urine analysis and have generally been measured based on a reagent strip test. In this study, these two substances were measured using mid-infrared absorption spectroscopy. Samples were prepared from a commercial synthetic urine product. Glucose and albumin were added as well as red blood cells, which are expected to create the most spectroscopic interference of any substance. Concentrations of these substances were varied independently. Optimal wavelength regions were determined from a partial least squares regression analysis (glucose 980 - 1150/cm, albumin 1400 - 1570/cm). Interference by other substances increased the differences between measured and predicted values. Albumin measurement in particular weres heavily influenced by the presence of glucose and red blood cells. Depending on the inference by other substances, measurement errors were 29.85${\sim}$45.19 mg/dl for a glucose level between 0 and 1000 mg/dl and 14.0${\sim}$93.11 mg/dl for an albumin level of 0 ${\sim}$ 500 mg/dl. Our study proposes an alternative to the chemical test-strip analysis, which shows only discrete concentration levels.

광용적맥파(PPG)를 이용한 호흡수 측정에 있어서 동잡음을 이용한 정확도 향상

허영정 ( Young Jung Huh ),윤길원 ( Gil Won Yoon ) 한국센서학회 2008 센서학회지 Vol.17 No.6

동적인 온도 보정 방법에 의한 전기 전도도의 측정

차용대 ( Yong Dae Cha ),윤길원 ( Gil Won Yoon ) 한국센서학회 2008 센서학회지 Vol.17 No.3

시간 분해 반사율에 의한 생체조직의 흡수계수와 산란계수 측정

전계진,박승한,김웅,윤길원,Jeon, Kye-Jin,Park, Seung-Han,Kim, Ung,Yoon, Gil-Won 대한의용생체공학회 1997 의공학회지 Vol.18 No.4

본 연구에서는 생체조직의 흡수계수와 산란계수를 비침습적으로 측정하는 방법에 관하여 연구하였다. 피코초 영역의 펄스폭을 갖는 레이저광으로 조직을 조사하고 산란반사된 빛을 시간상관 단일 광자 계수법을 이용하여 피코초 시간영역에서 측정하였다. 측정된 시간분해 반사율의 최대치에 이르는 시간 및 나중소멸부분의 점근선의 기울기로부터 계산되는 값과 디컨블루션방법에 의한 곡선맞춤으로 얻은 값을 비교하여 서로 잘 일치함을 확인하였다. 매질의 산란이 커질수록 흡수가 작을수록 근사식은 더 잘 맞으므로 가시광선부터 근적외선의 파장영역에서 흡수에 비해 산란이 매우 큰 생체조직의 광특성을 비침습적으로 측정하는 중요한 방법이 될 수 있다. A non-invasive technique to measure absorption and scattering coefficients was investigated The reflected backscattered light from the surface of phantom and biological tissue was obtained by using a time-correlated single photon counting system in pico-second time domain. The absorption and scattering coefficients were acquired by the time of peak and asymptotic behavior of the time-resolved reflectance curve and agreed well the ones that is obtained with deconvolution method It was found that the approximation method was good for biological medium to calculate optical properties due to its convenience and accuracy.

소형화 및 저전력소모를 구현한 실시간 생체신호 측정기 개발

조정현 ( Jung Hyun Cho ),윤길원 ( Gil Won Yoon ) 한국센서학회 2006 센서학회지 Vol.15 No.5

관측중단 하에서의 부트스트랩 와이블 분위수 관리도의 개발

김성준(Seong-joon Kim),윤길원(Gil-won Yoon),박정열(Jeong-yeol Park),방선호(Seon-ho Bang) 한국신뢰성학회 2018 한국신뢰성학회 학술대회논문집 Vol.2018 No.5

R&D단계에서 확보된 제품의 신뢰성이 양산단계에서 지속적으로 유지될 수 있도록 관리하는 것은 매우 중요하다. 이 때, 일반적으로 와이블 분포가 수명분포로 널리 사용되며 낮은 분위수를 관리 특성치로 설정하게 된다. 하지만, 신뢰성 데이터는 관측중단 형태로 얻어지는 경우가 대부분임에도 이를 고려한 분위수 관리도에 대한 연구는 부족한 실정이다. 본 연구는 데이터가 구간관측중단 형태로 얻어지며 와이블 분포를 따르는 경우, 부트스트랩 방법을 이용하여 관리한계선을 설정하는 분위수 관리도를 제안한다. 수치실험을 통해 부트스트랩 방법과 다른 근사방법을 적용하여 관리도의 성능을 평가하고 비교하였다. 제안된 방법은 휴대기기 디스플레이 패널의 강도(strength) 사례에 적용하여 양산환경에서 제품의 신뢰성을 관리하는데 유용하게 사용될 수 있음을 예시하였다.

노인을 위한 원격 낙상 검출 시스템

이용규 ( Yong Gyu Lee ),천대진 ( Dae Jin Cheon ),윤길원 ( Gil Won Yoon ) 한국센서학회 2011 센서학회지 Vol.20 No.6

The population of elderly people increases rapidly as our society moves towards the aged one. Healthcare for the elderly becomes an important issue and falling down is one of the critical problems although not well recognized. In this study, a fall detection system was developed using a 3-axis accelerometer. Analyzing fall patterns, we took into account the degree of impact, posture angle, the repetitions of similar movements and the activities after a potential fall and proposed an algorithm of fall detection. Information of the fall sensor was sent to a remote healthcare server through the wireless networks of Zigbee and WLAN. Our system was designed to monitor multiples users. 12 persons participated in experiment and each one performed 24 different movements. Our proposed algorithm was compared with other reported ones. Our method produced the excellent results having a sensitivity of 96.4 % and a specificity of 100 % whereas other methods had a sensitivity range between 87.5 % and 94.8 % and a specificity range between 63.5 % and 83.3 %.

U-헬스 센서 네트워크 시스템의 생체신호 압축 처리

이용규 ( Yong Gyu Lee ),박지호 ( Ji Ho Park ),윤길원 ( Gil Won Yoon ) 한국센서학회 2012 센서학회지 Vol.21 No.5

A sensor network system can be an efficient tool for healthcare telemetry for multiple users due to its power efficiency. One drawback is its limited data size. This paper proposed a real-time application of data compression/decompression method in u-Health monitoring system in order to improve the network efficiency. Our high priority was given to maintain a high quality of signal reconstruction since it is important to receive undistorted waveform. Our method consisted of down sampling coding and differential Huffman coding. Down sampling was applied based on the Nyquist-Shannon sampling theorem and signal amplitude was taken into account to increase compression rate in the differential Huffman coding. Our method was successfully tested in a ZigBee and WLAN dual network. Electrocardiogram (ECG) had an average compression ratio of 3.99: 1 with 0.24% percentage root mean square difference (PRD). Photo-plethysmogram (PPG) showed an average CR of 37.99: 1 with 0.16% PRD. Our method produced an outstanding PRD compared to other previous reports.

2000년도 종합학술대회 발표 우수총헤모글로빈 농도를 비침습적으로 측정하기 위한 400-2500nm 대역의 흡수 스펙트럼 분석

김수진,김연주,윤길원,김홍식,전계진 한국센서학회 2001 센서학회지 Vol.10 No.6

Absorption spectra of blood components have been measured for the purpose of predicting the total hemoglobin concentration. We obtained absorption spectra of major blood components from the visible to near-infrared of 400∼2500nm region. In the near-infrared, water is the main absorbing constituent. The amount of water in the sample cell varies depending on the volume of solute concentration(water displacement). We acquired water-compensated spectra by considering the variation of water volume depending on the variation of analyte concentration. Those spectra show inherent absorption peaks of analytes and linearity with respect to concentration. We selected wavelengths for non-invasive measurement of hemoglobin concentration considering the scattering effect of tissue and the interference of other blood components.

십이지장-위 역류의 진단에 있어서 24-Hour Ambulatory Bile Reflux Monitoring(Bilitec)의 문제점

김홍식,이화영,윤길원,고광철,김재준,백승운,이종철,손정일,이풍렬,전성국 대한소화기학회 1998 대한소화기학회지 Vol.30 No.2

Background/Aims: Duodenogastric reflux is thought to be a potential cause of functiona] dyspepsia but this point is still in debate. Many types of tests were used to diagnose duodenogastric reflux but none was accepted as the gold standard. In recent years, a 24-hour ambulatory bile reflux monitoring(Bilitec^(R)) was introduced. This study was done to analyze the amount and the frequency of duodenogastric reflux and to investigate the efficacy and prnblems of Bilitec^(R) in functional dyspeptic patients and normal controls. Methods: We first measured optical absorbance of 20 common Korean foods. We exarnined 10 functional dyspeptic patients with endoscopic evidence of bile regurgitation, 10 gastritis or peptic ulcer disease patients and 10 asymptomatic normal controls with Bilitec^(R). Duodenogastric reflux was considered as positive when bile absorbance exceeded 0.14 during Bilitec^(R) examination. We also investigated technical difficulties and patients tolerance during the Bilitec^(R) examination. Results: Among the 20 Korean foods, kimchi, soybean paste, cabbage, apple, and egg gave false positives on the Bilitec examination. Technically, the probe was located optimally on the antrum in only 23 out of 30 subjects, but the probe was located on the body in two, the fundus in three and the probe could not be inserted due tv poor cooperation in three. At the end of the examination, 54% of subjects complained of more discomfort when compared to endoscopy. There was no significant difference in duodenogastric reflux between functional dyspeptic patients and asymptomatic normal controls. There was one case which failed the Bilitec^(R) exam due to probe malfunction. Conclusions: Bilitec^(R) examination is thought to be the best method in the diagnosis of duodenogastric reflux yet. However, some protilems such as false positivity influenced by food material, technical difficulty in locating the probe, probe malfunction and patients discomfort exist. In this study, the role of duodenogastric reflux as a cause of functional dyspepsia is not certain.