• Clinical and Experimental Pediatrics
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• 제50권6호
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• pp.549-555
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• 2007

목 적 : 성인에서 맥파 속도와 발목 상완 동맥압 지수는 동맥 경직도를 측정할 수 있는 비침습적 방법이며 혈압, 고지혈증 등의 심혈관계 위험 인자와 연관성이 있어 심혈관계 질환과 관련이 있음이 알려져 있다. 본 연구는 우리나라 청소년에서 신장, 체중, 체질량 지수와 혈압, 맥파 속도, 발목 상완 동맥압 지수를 측정하였고 이들 사이의 상관성을 알아보고 정상 기준값를 확립하고자 하였다. 방 법 : 서울 시내 3개 고등학교에 재학 중인 15-16세 사이의 청소년 392명(남자 213명, 여자 179명)을 대상으로 신장, 체중, 체질량지수, 좌우 상완 및 발목의 수축기, 이완기, 평균 혈압과 양측 맥파 속도, 발목 상완 동맥압 지수, 박출 시간, 전구출기를 VP-1000(Colin사, Komaki, Japan)을 이용하여 측정하였다. 결 과 : 사지의 수축기, 이완기 평균 혈압은 남자에서 여자보다 유의하게 높은 값을 보였다(P<0.05). 우측 상완-발목 맥파 속도는 남자에서 $1,015.4{\pm}130.0cm/sec$, 여자에서 $947.6{\pm}105.1cm/sec$로서 남자에서 유의하게 높은 값을 보였다. 좌측 상완 발목 맥파 속도도 마찬가지로 남자에서 $1,023.4{\pm}132.5cm/sec$, 여자에서 $954.6{\pm}102.4cm/sec$로 남자에서 유의하게(P<0.05) 높은 값을 보였다. 발목 상완 동맥압 지수는 남녀 간에 유의한 차이를 보이지 않았다. 우측 상완-발목 맥파 속도의 기준값는 남자에서 1,032.4 cm/sec, 여자에서 963.1 cm/sec이었고, 좌측 상완-발목 맥파 속도는 남자에서 1,041.3 cm/sec, 여자에서 969.7 cm/sec이었다. 우측 발목 상완 동맥압 지수의 기준값은 남자에서 1.06, 여자에서 1.06이었으며, 좌측 발목 상완 동맥압지수의 기준값은 남자에서 1.05, 여자에서 1.06이었다. 맥파 속도는 사지 모두에서 혈압이 높아질수록, 유의한 양의 상관관계를 보였다. 또한 신장이 커질수록, 체중이 증가할수록, 체질량지수가 커질수록 사지의 혈압이 증가하는 유의한 양의 상관관계를 보였다. 반면, 발목 상완 동맥압 지수는 남녀 사이에 유의한 차이가 없었으며, 체중, 신장, 체질량지수 어느 것과도 유의한 상관관계가 없었다. 결 론 : 혈압은 신장, 체중, 체질량지수에 따라 높아지며 맥파 속도와 혈압 사이에도 유의한 양의 상관관계가 있다. 정상 청소년에서 측정한 맥파 속도의 기준값을 바탕으로 심혈관계 질환의 위험도를 조기 발견하고 예측하는데 유용하게 사용할 수 있을 것으로 생각한다.

• 한국정보통신학회논문지
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• 제25권7호
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• pp.955-961
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• 2021

현대전에서는 전파를 이용하여 적의 정보를 알아내거나, 적이 탐지하려는 아군 정보를 보호하는 임무를 수행하는 전자전 분야의 중요성이 증가하고 있다. 전자전 분야의 대표적인 전자공격 방법 중 하나인 레이다 재밍기법은 적 레이다를 교란 및 기만하여 아군의 위치 정보가 노출되는 것을 방지한다. 레이다 재밍기법 중 하나인 속도기만 재밍기법은 도플러효과를 이용하여 표적의 속도와 위치를 추적하는 펄스 도플러 레이다를 대상으로 사용된다. 속도기만 재밍기법은 DRFM (Digital Radio Frequency Memory)을 이용하여 수신신호를 주파수 변조해서 송신하는 방법으로 구현할 수 있다. 본 논문은 위상 샘플방식 DRFM을 이용하여 속도기만 재밍기법 중 하나인 VGPO/VGPI 재밍기법을 구현하는 방안을 기술하고, 제작한 보드를 통해서 주입신호 환경 하에서 VGPO/VGPI 재밍기법의 동작을 검증하였다.

• Journal of Genetic Medicine
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• 제14권1호
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• pp.8-17
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• 2017

Purpose: Pulse wave velocity (PWV) is an indicator of arterial stiffness, and is considered a marker of vascular damage. However, a genome-wide association study analyzing single nucleotide polymorphisms (SNPs) associated with brachial-ankle PWV (baPWV) has not been conducted in healthy populations. We performed this study to identify SNPs associated with baPWV in healthy populations in Korea. Materials and Methods: Genomic SNPs data for 2,407 individuals from three sites were analyzed as part of the Korean Genomic Epidemiologic Study. Without replication samples, we performed multivariable analysis as a post hoc analysis to verify the findings in site adjusted analysis. Healthy subjects aged between 40 and 70 years without self-reported history or diagnosis of hypertension, diabetes, hyperlipidemia, heart disease, cerebrovascular disease and cancer were included. We excluded subjects with a creatinine level >1.4 mg/dL (men) and 1.2 mg/dL (women). Results: In the site-adjusted association analysis, significant associations (P<$5{\times}10^{-8}$) with baPWV were detected for only 5 SNPs with low minor allele frequency. In multivariable analysis adjusted by age, sex, height, body mass index, mean arterial pressure, site, smoking, alcohol, and exercise, 11 SNPs were found to be associated (P<$5{\times}10^{-8}$) with baPWV. The 5 SNPs (P<$5{\times}10^{-8}$) linked to three genes (OPCML, PRR35 and RAB40C) were common between site-adjusted analysis and multivariable analysis. However, meta-analysis of the result from three sites for the 11 SNPs showed no significant associations. Conclusion: Using the recent standard for genome-wide association study, we did not find any evidence of significant association signals with baPWV.

• 센서학회지
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• 제13권5호
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• pp.383-391
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• 2004

In this study, we implemented the pulse transit time (PTT) system to examine usefulness of the monitoring method of distensibility and elasticity using photoplethysmography sensor in vivo. PTT is defined as the time interval between the peak of QRS complex in ECG signal and the maximum slope point of photoplethysmography. these two signals were converted to digital data by means of AID converter, then PTT was evaluated by heartbeat using PC. Results of analysis were displayed as a graph using spline interpolation method. The variance of PTT was measured repetitiously to verify efficiency of PTT system in resting state and hyperemic state. Repeated measurement of PTT was not same value but showed that coefficients of correlation were related with each other as 0.8302 (P<0.01) in resting state. And also repeated measurement of PTT showed significant correlation as 0.868 (P<0.01) in the hyperemic state. These result showed that PTT is reflect on transient pressure variance in the artery and is very useful method for the evaluation of prognosis of the hypertension and arteriosclerosis.

• 한국결정성장학회지
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• 제2권1호
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• pp.30-36
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• 1992

$LiNbO_3$단결정의 조성비 변화에 따른 탄성표면파 특성을 축정하기 위해 47-50 $Li_2O$ mol% 조성의 $LiNbO_3$단결정을 성장시켜 $128^{\circ}$Y cut wafer를 제조하였다. 제작된 wafer 위에 사진식각법을 이용하여 지연선(Delay line)을 형성시켰다. Pulse-echo overlap mehtod로 지연시간을 측정하여, 탄성표면파 속도$(V_s)$, 전기기계결합계수$(K_s^2)$ 및 $-50^{\circ}C~100^{\circ}C$ 온도 범위에서 지연시간 온도계수(TCD)의 조성비에 대한 의존성을 조사하였다.

• Advances in concrete construction
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• 제4권2호
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• pp.145-160
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• 2016

Marble is a metamorphic rock used widely in construction which increases amount of marble powder obtained from it. Marble powder is a waste product obtained from marble during its processing. Marble waste is high in calcium oxide content which is cementing property but it creates many environmental hazards too if left in environment or in water. In this research, partial replacement of cement and sand by waste marble powder (WMP) has been investigated. Seven concrete mixtures were prepared for this investigation by partially replacing cement, sand with WMP at proportions of 0%, 10% and 15% by weight separately and in combined form. To determine compressive strength, flexural strength and split tensile strength of concrete made with waste marble powder, the samples at the curing ages of 7, 28 and 90 days was recorded. Different tests of durability were applied on samples like ultrasonic pulse wave test, absorption and sorptivity. For further investigation all the results were compared and noticed that WMP has shown good results and enhancing mechanical properties of concrete mix on partially replacing with sand and cement in set proportions. Moreover, it will solve the problem of environmental health hazard.

• 비파괴검사학회지
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• 제19권2호
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• pp.118-128
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• 1999

초음파 비파괴검사와 관련하여 많은 측정 방법들이 사용되고 있으며, 전형적인 예로서 재료성질 결정, 미시구조 특성 평가, 결함의 탐상 등을 들 수 있다. 이러한 응용에서 속도와 감쇠계수는 가장 흔히 요구되는 초음파 측정 파라미터이다. 본 연구에서는 수침식 펄스 에코방법으로 속도 및 감쇠 측정을 위한 5가지 해석 알고리즘 (펄스 겹침법, 상호 상관법, Fourier 변환, Hilbert 변환, Wavelet 변환)을 소개하였다. 먼저 연속한 두 저면 반사파 사이의 시간지연 측정을 위하여 펄스 겹침법, 상호 상관법, Fourier 변환에 의한 위상 기울기법 및 Hilbert 변환법을 사용하였다. 주파수 의존위상/군속도와 감쇠계수는 Fourier 변환에 의한 위상 및 진폭 스펙트럼이 사용되었으며, 이와 더불어 시간-주파수 해석법인 wavelet 변환이 이용되었다. 사용된 시편은 분산을 무시할 수 있는 강판과 약한 분산성을 지닌 기공을 함유한 복합판재이다. 각 측정 알고리즘의 특성에 대해 논의하였으며 측정된 결과들을 서로 비교하였다.

• 대한지역사회영양학회지
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• 제29권2호
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• pp.81-96
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• 2024

Objectives: This study aimed to investigate arterial stiffness index, physical activity, and food and nutrient intake in middle-aged adults over 40 years when the incidence of cardiovascular disease begins to increase. Methods: This study included 106 subjects (48 males and 58 females) aged between 40 and 64 years. The arterial stiffness index (brachial-ankle pulse wave velocity [baPWV], and ankle-brachial index [ABI]) were measured using a blood pressure pulse wave testing device. Physical activity was assessed using the Korean version of the Global Physical Activity Questionnaire, and food and nutrient intake was calculated using the Food Frequency Questionnaire. Results: The mean age of the subjects was 54.4 years. Although the ABI of the subjects was within the normal range, they were divided into tertiles to compare physical activity and food and nutrient intake. In males, the time spent on moderate to vigorous physical activity (MVPA) was significantly higher in T3 (600.6 min/week) than in T1 (304.4 min/week). In females, the time spent in sedentary behavior was significantly lower in T3 (294.5 min/week) than in T1 (472.1 min/week). In addition, the frequency of fish consumption was significantly higher in T3 (1.27 frequency/day) than in T1 (0.64 frequency/day) in females. Polyunsaturated fatty acid (PUFA) and ω-3 fatty acid intake, adjusted for energy intake, were significantly positively correlated with ABI (r = 0.200 and r = 0.218, respectively). Conclusions: High MVPA (in males), low sedentary behavior (in females), and PUFA and ω-3 fatty acid intake through fish consumption may be associated with low peripheral artery stiffness. Therefore, arteriosclerosis can be prevented through physical activity and proper dietary therapy.

• 대한한방내과학회지
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• 제27권2호
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• pp.416-428
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• 2006

Objectives : Arterial stiffness and pulse pressure are related to cardiovascular and cerebrovascular survival and longevity. This study is aimed at examining the effects of Chungpyesagan-tang on arterial stiffness and Pulse pressure in acute stroke Patients. Methods: The subject of this study was acute strike Patients within 1 week after ictus, with Cardio-ankle vascular index(CAVI) higher than 9.0. They were divided into two groups: A treatment group (n=44) and a control group(n=46). For two weeks, Chungpyesagan-tang was given to the former, other herbal medicines to the latter. used for stroke patients for the control group for 2 weeks. At the end of first and second week, CAVI, pulse Pressure, National Institute of Health stroke scale(NIHSS), Modified Barthel Index(MBI) were measured. Serum lipid Profile, aspartate transaminase(AST), alanine transaminase(ALT). blood urea nitrogen(BUN), creatinine were also measured at the end of the study. Results : After 2 weeks, CAVI and Pulse Pressure in Chungpyesagan-tane group were significantly tower than those in the control group(P<0.05). NIHSS and MBI were improved in both groups. But there was no significant difference between the treatment group and the control group in terms of the NIHSS and MBI. Conclusions : We suggest Chungpyesagan-tanghas desirable effects on arterial stiffness and Pulse Pressure of acute stroke patients. It can improve morbidity and mortality of patients on the basis of influencing vascular stiffness and increased pulse pressure.

• Structural Engineering and Mechanics
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• 제13권5호
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• pp.543-556
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• 2002

A dynamic elastic local buckling analysis is presented for a pile subjected to an axial impact load. The pile is assumed to be geometrically perfect. The interactions between the pile and the surrounding soil are taken into account. The interactions include the normal pressure and skin friction on the surface of the pile due to the resistance of the soil. The analysis also includes the influence of the propagation of stress waves through the length of the pile to the distance at which buckling is initiated and the mass of the pile. A perturbation technique is used to determine the critical buckling length and the associated critical time. As a special case, the explicit expression for the buckling length of a pile is obtained without considering soil resistance and compared with the one obtained for a column by means of an alternative method. Numerical results obtained show good agreement with the experimental results. The effects of the normal pressure and the skin friction due to the surrounding soil, self-weight, stiffness and geometric dimension of the cross section on the critical buckling length are discussed. The sudden change of buckling modes is further considered to show the 'snap-through' phenomenon occurring as a result of stress wave propagation.