• 지역사회간호학회지
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• 제16권4호
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• pp.527-533
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• 2005

Purpose: The purpose of this study was to validate waist circumference (WC) and waist to hip ratio (WHR) corresponding to body mass index (BMI) of $25kg/m^2$ and to survey the prevalence of hypertension according to obesity in female college students. Method: Weight, height, waist and hip circumferences and blood pressure were measured for each of 286 female college students in J City, Chungbuk. Results: The subjects' mean BMI was $21.4kg/m^2$, and the estimated prevalence of obesity was 11.2%. The subjects, the 80th-90th percentile of whom had BMI exceeding $25kg/m^2$, were found to have WC of 75-78.1 cm and WHR of 0.79-0.80, respectively. Of the subjects with obesity($BMI{\geq}25kg/m^2$), 53.1% exhibited abdominal obesity ($WC{\geq}80cm$) and 40.6% had WHR over 0.80. Systolic and diastolic blood pressure were correlated with BMI, WC, and WHR. The prevalence rate of hypertension in subjects with obesity($BMI{\geq}25kg/m^2$) was 25%. Additionally, the prevalence rate of hypertension in subjects with abdominal obesity ($WC{\geq}80cm$) was 39.1%. Conclusions: Our study indicates that WC corresponding to BMI of $25kg/m^2$ in female subjects in their twenties is different from that of adult women. We also found that the prevalence rate of hypertension in subjects with abdominal obesity was high. Therefore. we suggest further studies to determine the cutoff value of WC for evaluating abdominal obesity and to investigate the long-term effects of obesity on women in their twenties.

• 한국정보통신학회논문지
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• 제20권2호
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• pp.375-384
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• 2016

본 논문에서는 스테레오 영상과 스테레오 영상 바깥 시점의 위성 영상 그리고 상응하는 깊이 영상이 입력으로 주어질 때 이 입력 영상들을 압축에 적합한 포맷으로 변환하고 활용하여 중간시점 영상을 합성하는 새로운 기법을 제안한다. 송출 단에서 깊이 영상들은 하나의 global 영상으로, 위성영상은 시점 이동 시에 발생하는 프레임 밖의 영역 및 가려짐 영역과 같은 홀 영역에만 해당하는 residual 영상으로 변환 후에 데이터 량을 줄이기 위하여 다운샘플링하고 주시점의 스테레오 영상과 더불어 HEVC 코덱으로 부호화 한 후 전송한다. 수신 단에서 복호화된 각 입력 영상들을 이용하여 스테레오 영상 간 그리고 스테레오 영상과 위성 영상간의 중간시점 영상을 합성한다. 실험을 통하여 제안한 포맷을 이용하여 합성한 중간 시점 영상을 MVD(Multiview Video plus Depth) 포맷을 이용하여 합성한 중간 시점 영상과 비교했을 때 전송하는 데이터의 비트율(bit-rate) 대비 객관적 그리고 주관적 화질이 뛰어남을 확인하였다.

• 비파괴검사학회지
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• 제23권3호
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• pp.254-262
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• 2003

본 연구는 목재(참나무 판목 판재) 건조 중 발생하는 음향방출 신호에 대하여 목재 내 수분이동에 의한 신호와 표면할열에 의한 신호를 해석하고 분류하기 위하여 수행되었다. AE 신호의 특징값들에 대한 상관분석을 실시하여 상호의존성이 높은 변수를 제거한 후 주성분 분석을 실시하였다. AE 변수들을 독립변수로 한 분류기와 주성분들을 독립변수로 한 분류기에 대하여 분류성능을 비교하였다. 목재 건조 시 발생하는 표면할열과 수분이동에 따른 AE 신호 파형을 분석한 결과 대체적으로 표면할열에 의한 신호가 최대진폭이 크며 상승시간이 팎고 상대적으로 고주파의 신호인 것으로 분석되었다. 다중 회귀분석모델을 이용하여 수분이동에 의한 신호와 표면할열에 의한 신호를 분류할 수 있는 분류기를 개발하고 평가한 결과 개별 AE 변수들을 독립변수로 하는 분류기 보다 주성분들을 독립변수로 하는 분류기의 분류성능이 양호한 것으로 나타났다.

• 한국재료학회지
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• 제24권9호
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• pp.488-494
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• 2014

The effect of tungsten (W) addition on the hardenability of low-carbon boron steels was investigated using dilatometry, microstructural observations and secondary ion mass spectroscopy. The hardenability was discussed with respect to transformation behaviour aspects depending on the segregation and precipitation of boron at austenite grain boundaries. A critical cooling rate producing a hardness corresponding to 90 % martensite structure was measured from a hardness distribution plot, and was used as a criterion to estimate hardenability at faster cooling rates. In the low-carbon boron steel, the addition of 0.50 wt.% W was comparable to that of 0.20 wt.% molybdenum in terms of critical cooling rate, indicating hardenability at faster cooling rates. However, the addition of 0.50 wt.% W was not more effective than the addition of .0.20 wt.% molybdenum at slower cooling rates. The addition of 0.20 wt.% molybdenum completely suppressed the formation of eutectoid ferrite even at the slow cooling rate of $0.2^{\circ}C/s$, while the addition of 0.50 wt.% W did not, even at the cooling rate of $1.0^{\circ}C/s$. Therefore, it was found that the effect of alloying elements on the hardenability of low-carbon boron steels can be differently evaluated according to cooling rate.

• Journal of Radiation Protection and Research
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• 제6권1호
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• pp.8-24
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• 1981

This paper presents flux-to-dose-rate conversion factors for neutrons and gamma rays based on the American National Standard Institute(ANSI) N666. These data are used to calculated the dose rate distribution of neutron and gamma ray in radiation fields. Neutron flux-to-dose-rate conversion factors for energies from $2.5{\times}10^{-8}$ to 20 MeV are presented; the corresponding energy range for gamma rays is 0.01 to 15 MeV. Flux-to-dose-rate conversion factors were calculated, under the assumption that radiation energy distribution has nonlinearity in the phantom, have different meaning from those values obtained by monoetiergetic radiation. Especially, these values were determined with the cross section library. The flux-to-dose-rate conversion factors obtained in this work were in a good agreement to the values presented by ANSI. Those data will be a useful for the radiation shielding analysis and the radiation dosimetry in the case of continuous energy distributions.

• 한국초전도ㆍ저온공학회논문지
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• 제22권1호
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• pp.24-28
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• 2020

Heat leakage is an important parameter to reflect heat insulated performance of cryogenic vessel. According to the current standard requirements, it needs to measure the daily evaporation rate to indicate heat leakage. The test needs-over 24h after cryogenic vessel in heat equilibrium as standard required, therefore test efficiency is poor and new efficient method is required to cut test time. First of all, the volume of instantaneous evaporated gas and heat leakage are calculated by the current standard corresponding to the maximum allowable daily evaporation rate of cryogenic vessel. Depending on the relationship between real daily evaporation rate and maximum allowable daily evaporation rate of cryogenic vessel, we designed a new test method based on the pressure changes over time in cryogenic vessel to determine whether its heat insulated performance meets requirements or not. Secondly, the heat transfer process was analyzed in measurement of cryogenic vessel, and the heat transfer equations of whole system were established. Finally, the test was completed in four hours; meanwhile the heat leakage and daily evaporation rate of cryogenic vessel are calculated basing on test data.

• 대한임베디드공학회논문지
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• 제17권1호
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• pp.25-32
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• 2022

IR-UWB radar has been regarded as the most promising technology for non-contact respiration and heartbeat monitoring because of its ability of detecting slight motion even in submillimeter range. Measuring heart rate is most challenging since the chest movement by heartbeat is quite subtle and easily interfered with by a random body motion or background noise. Additionally, periodic sampling can be limited by the performance of computer that handles the radar signals. In this paper, we deploy Lomb-Scargle periodogram method that estimates heart rate even with irregularly sampled data and uneven signal amplitude. Lomb-Scargle periodogram is known as a method for finding periodicity in irregularly-sampled and noisy data set. We also implement a motion detection scheme in order to make the heart rate estimation pause when a random motion is detected. Our scheme is implemented using Novelda's X4M03 radar development kit and its corresponding drivers and Python packages. Experimental results show that the estimation with Lomb-Scargle periodogram yield more accurate heart rate than the method of measuring peak-to-peak distance.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.243-244
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• 2014

The opposed flow flame in a mesoscale channel was constructed to observe the flame stabilization behaviors at low strain rate conditions (<$10s^{-1}$). The purpose of this study is to get the overall flame behaviors of partially premixed flames with oxygen enhanced conditions at low strain rates. The oxygen ratio in oxidizer was changed from 18 to 30 %. Conclusively, the flame extinction limit approached to about $1s^{-1}$, and divided into three representative regimes corresponding to self propagating flame, transitional flame, quenching flame regimes.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.191-194
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• 2003

The results from a systematic study of the response of a Ti-6Al-4V alloy under quasi-static and dynamic loading at different strain rates and temperatures are presented. It has been shown that the work-hardening rate decreased as the strain rate and the strain increased. The correlations and predictions using modified KHL (Khan-Huang-Liang) viscoplastic constitutive model are compared with those from JC (Johnson-Cook) model and experimental observations. Overall, KHL model correlations and predictions compared much more favorably than the corresponding JC model predictions and correlations.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.393-397
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• 2007

A Haematococcus pluvialis strain isolated from the ruins of Ephesus in Turkey was investigated as regards its adaptation to laboratory conditions and maximum growth rate. In the first stage of the experiment, the growth of H. pluvialis was compared in common culture media. Furthermore, in an effort to minimize the culture costs, the second stage of the experiment compared the growth rate in the culture medium selected in the first stage with that in commercial plant fertilizers. The results demonstrated that the maximum cell concentration of 0.90 g/l, corresponding to a growth rate of $0.150d^{-1}$, was found with an N-P-K 20:20:20 fertilizer under a light intensity of $75{\mu}mol$ photons $m^{-2}s{-1}$ on the $12^{th}$ day of cultivation.