• 한국철도학회논문집
• /
• 제20권5호
• /
• pp.649-657
• /
• 2017

본 연구의 목적은 궤도형식별로 사용레일의 피로수명을 평가하는 것이다. 이를 위해 궤도형식별 사용레일에 대한 실내피로시험을 수행하여 파괴확률 50%~0.01% 의 S-N 선도를 도출하고, 실험데이터에 대한 가중치 확률해석기법을 사용하여 피로수명을 산출하였다. 여기서, 레일표면요철 및 열차속도를 고려한 사용레일의 휨응력은 기존 연구결과 도출된 레일휨응력 예측식을 이용하여 구하고, S-N 선도로부터 사용레일의 잔존수명을 평가하였다. 평가결과, 자갈도상의 경우 레일의 피로수명이 현 레일교환기준에 비해 약 2억톤 이상 높았고, 콘크리트도상의 레일 피로수명이 자갈궤도에 비해 약 3억톤 이상 높은 것으로 나타났다. 따라서 누적통과톤수에 의한 레일교환기준을 자갈궤도와 콘크리트궤도로 구분할 필요가 있으며, 레일연마를 통한 레일관리가 이루어진다면 기준값이 아닌 목표값으로 관리할 필요가 있다.

• 대한정형도수물리치료학회지
• /
• 제11권2호
• /
• pp.62-70
• /
• 2005

The determination of peripheral nerve conduction velocity is an important part to electrodiagnosis. Its value as neurophysiologic investigative procedure has been known for many years but normal value of median and ulnar motor nerve was poorly reported in Korea. To evaluate of median and ulnar motor nerve terminal latency, amplitude of CMAP(compound muscle action potential), conduction velocity and F-wave latency for obtain clinically useful reference value. 71 normal volunteers(age, 19-65 years; 142 hands) examined who has no history of peripheral neuropathy, diabetic mellitus, chronic renal failure, endocrine disorders, anti-cancer medicine, anti-tubercle medicine, alcoholism, trauma, radiculopathy. Nicolet Viking II was use for detected terminal latency, amplitude of CMAP, conduction velocity and F-wave latency of median and ulnar motor nerve. Data analysis was performed using SPSS. Descriptive analysis was used for obtain mean and standard deviation, independent t-test was used to compare between Rt and Lt side also compare between different in genders. The results are summarized as follows: 1. Median motor nerve terminal latency was right 3.00ms, left 2.99ms and there was no significantly differences between right and left side and genders. 2. Median motor nerve amplitude of CMAP was right 17.26mV, left 1750mV and there was no significantly differences between right and left side and genders. 3. Median motor nerve conduction velocity was right 57.89m/sec, left 58.03m/sec and there was no significantly differences between right and left side and genders. 4. Median motor nerve F-wave latency was right 25.74ms, left 25.59ms and there was significantly differences between genders. 5. Ulnar motor nerve terminal latency was right 2.38ms, left 2.45ms and there was significantly differences between right and left side. 6. Ulnar motor nerve amplitude of CMAP was right 15.99mV, left 16.02mV and there was no significantly differences between right and left side and genders. 7. Ulnar motor nerve conduction velocity was right 60.35m/sec, left 59.73m/sec and there was no significantly differences between right and left side and genders. 8. Ulnar motor nerve F-wave latency was right 25.53ms, left 25.57ms and there was significantly differences between genders.

• 대한정형도수물리치료학회지
• /
• 제11권2호
• /
• pp.13-18
• /
• 2005

The ulnar nerve extends down the arm, across the elbow, and into the hand. It provides sensation to the little and ring fingers and activates many of the small muscles in the hand. The determination of peripheral nerve conduction velocity is an important part of ulnar nerve evaluation. The electrodiagnostic value as neurophysiologic investigative procedure has been known for many years but normal value of digital nerve was not reported in Korea. The purpose of this investigation was to measure the digital nerve conduction velocity of ulnar nerve for obtain clinically useful reference value and compare difference in each fingers and then compare with the other countries. 71 normal Korean volunteers (age, 19-65 years; 142 hands) examined who has no history of peripheral neuropathy, diabetic mellitus, chronic renal failure, endocrine disorders, anti-cancer medicine, anti-tubercle medicine, alcoholism, trauma, radiculopathy. Nicolet Viking II (EMG machine) was use for detected conduction velocity and amplitude of digital nerves in ulnar nerve. Data analysis was performed using SPSS. Descriptive analysis was used for obtain mean and standard deviation and independent t-test was used to compare with ring and little finger. Conduction velocity of the right ring finger was 57.44m/sec and little finger was 55.32msec. The left ring finger was 55.55msec and little finger was 54.11msec. Amplitude of the right ring finger was $30.28{\mu}V$ and little finger was $48.36{\mu}V$. The left ring finger was $30.67{\mu}V$ and little finger was $52.76{\mu}V$. There were significantly difference between ring and little in amplitude (p<.05) but there were no statistically difference between conduction velocity of ring and little finger (p>.05). The amplitude of little finger are greater than ring finger. The present results revealed that electodiagnosis can easily perform in little finger for digital nerve of ulnar nerve study.

• 한국전산구조공학회논문집
• /
• 제32권6호
• /
• pp.383-390
• /
• 2019

본 논문에서는 AISC 표준 단면을 설계 변수로 하는 캔틸레버 타입 헬리데크 모델의 유전 알고리즘 최적설계를 소개한다. AISC 표준 단면을 단면 형상별로 분류하고 단면적 순으로 정렬한 후 정수 단면 번호를 부여하여 설계 변수로 최적설계를 수행하였다. 이 과정을 통하여 이산화된 설계 변수를 가지는 최적설계 문제를 해결하기 위해 유전 알고리즘을 적용하였다. 또한, 제약조건으로 허용응력 및 허용응력비 검사 조건을 모두 고려하여 구조물의 구조 안정성을 고려한 설계를 수행하였다. 최적설계 과정중 매 반복계산 마다 수행되는 구조 해석 시간을 단축시키기 위해 선형 중첩법을 사용하였고, 이를 통해 구조해석 시간을 약 75% 감소시킬 수 있었다. 또한 헬리데크 최적설계의 경량 효과를 높이기 위해 부재 그룹 세분화를 하였고, 그 결과를 선행 연구 모델, 기존의 부재 그룹 모델과 비교하였다. 그 결과 선행연구 대비 약 30톤의 부재를 절감할 수 있었으며, 구조적으로도 보다 안전한 헬리데크 설계를 얻을 수 있었다.

• 한국수자원학회논문집
• /
• 제44권5호
• /
• pp.363-376
• /
• 2011

하천 홍수해석 분야에서 가장 널리 이용되고 있는 1차원 동수역학 수치모형의 입력자료는 상하류단 경계조건, 조도계수, 하도단면 등이며, 계산 시간간격 및 거리간격의 선정은 계산결과의 정확성, 안정성, 효율성 확보를 위한 핵심 요소이다. 본 연구에서는 기존 단면간격 선정기법의 이론적 배경을 검토하였고, 매 시간단계별로 도출되는 흐름특성을 반영하여 계산거리간격을 추정하는 가변 계산거리간격 추정 기법을 제안하였다. 제안된 기법을 1차원 부정류 수치모형과 연계하여 Teton 댐 붕괴 및 한강 홍수 사상에 대해 적용함으로써 기존 고정 계산거리간격 추정 기법에 의한 해석결과와 비교하였다. 더 많은 내삽단면이 사용될 경우, 수치 수렴성 실험 결과는 수치해의 정확성과 안정성이 높아짐을 나타내었고, 본 연구에서 제안된 기법은 기존 고정 계산거리간격 추정기법보다 적은 단면개수로 동일한 정도의 정확도를 나타냄으로써 계산 효율성을 크게 향상시켰다. 본 연구에서 개발된 기법의 실무적용을 통해 정확성과 안정성뿐만 아니라 높은 효율성을 갖는 하천 홍수해석이 가능할 것으로 판단된다.

• 한국지반공학회논문집
• /
• 제19권3호
• /
• pp.53-64
• /
• 2003

사면을 포함한 경사지에 설치된 송전탑, 교각, 고층빌딩 등을 지지하는 말뚝은 풍하중, 지진, 차량 등에 의한 수평하중을 고려하여 설계되어야 한다. 이러한 사면이나 경사지에 설치된 수평하중을 받는 말뚝은 편평한 지반에 비하여, 수평지지력이 감소하기 때문이다. 그러므로 이러한 구조물은 일반적으로 강성이 높고, 대구경의 기초인 피어기초가 사용된다. 수평하중을 받는 피어기초는 일반적으로 장대말뚝과 다른 거동을 한다. 즉, 수평하중에 의하여 말뚝 자체의 회전이 발생하고, 그 회전의 중심점 상부의 사면측의 수동토압에 의존하여 지반파괴가 발생한다는 측면에서 짧은 강성 말뚝과 유사한 거동을 한다. 본 논문은 모래사면의 언덕 근처에 설치된 짧은 말뚝의 수평하중의 영향에 대한 실험 및 수치해석 결과를 포함한다. 대부분을 모형실험과 3차원 탄소성 유한요소해석의 비교, 결과를 기술하였다. 먼저, 사면 언덕에서 모형말뚝까지의 거리를 3종류로 구분하여 단항의 모형실험과 군항말뚝의 수평하중 특성을 파악하기 위하여 수평지반과 사면지반(경사 30$^{\circ}$)에 대하여 말뚝중심간의 거리를 각2종류로 모형실험을 실시하였다. 동시에 3차원 탄소성 유한요소법에 의한 수치해석을 통하여 모형실험의 결과와의 비교를 시도하였다. 사용된 모래지반은 배수조건하에서 삼축압축실험으로 재현하였다. 3차원 탄소성 유한요소해석에서 완전탄소성모델의 파괴기준은 Mohr-Coulomb식, 소성 포텐셜은 Drucker-Prage식을 이용한 MC-DP모델을 적용하였다. 연구결과, 3차원탄소성 유한요소법이 사질토 지반에 설치된 짧은 말뚝의 수평거동을 파악하는데 유효하다는 것을 확인하였다.

• 한국지반공학회논문집
• /
• 제28권9호
• /
• pp.23-30
• /
• 2012

본 논문은 토석류 발생사면에서 불포화토의 침투해석을 연계 수행한 사면안정해석 연구결과이다. 2006년 강원도 인제군과 2010년 경기도 양평군에 위치한 2개소의 토석류 발생사면에 대하여 현장조사를 수행하고 붕괴발생부에서 채취한 시료로 tempe pressure cell을 이용한 함수특성곡선과 새로이 개발된 불포화토 직접전단시험기를 사용하여 불포화토의 전단강도 정수를 구하였다. 실험을 통해 획득한 물성과 토석류 발생 당시의 강우자료를 바탕으로 상용프로그램 SEEP/W를 사용하여 불포화토 침투 해석을 실시하고 그 결과와 연동하여 사면안정해석 프로그램 SLOPE/W를 사용하여 사면활동을 분석하였다. 본 연구 결과 집중강우에 의한 불포화토 지반에 강우침투의 영향으로 지하수위의 상승과 포화도의 증가로 사면안전율이 감소하여 사면활동이 발생한 것으로 나타났다. 이러한 연구 방법을 통하여 실제 강우특성을 고려한 불포화토의 사면안정해석을 실시하는 것이 토석류 발생사면의 거동특성 중 특히 발생시점을 확인할 수 있는 합리적인 방법이라 판단된다.

• 한국임상약학회지
• /
• 제12권1호
• /
• pp.29-38
• /
• 2002

Hypertension is an important public health problem because it increases the risk of stroke, angina, myocardial infarction, heart failure, and end-stage renal disease. If it is not actively treated, morbidity and mortality increase with hypertension-induced complications and quality of life decreases. This study was to evaluate the use of antihypertensive drugs and blood pressure changes and to compare algorithms chosen (or the 1st and 2nd line therapy of hypertension based on the JNC VI recommendations. The medical charts of 222 patients with essential hypertension at St. Vincent's Hospital in Suwon from January 1997 to January 2000 were reviewed retrospectively. Data collection and analysis included baseline BP underlying diseases and complications, administered antihypertensives, BP changes, changes of antihypertensive regimen, and adverse effects with treatments. As results, the higher BP the patients had, the more frequent they had target organ damages and clinical cardiovascular diseases. Mean duration to reduce blood pressure less than 140/90 mmHg was 8 weeks in $85.3\%$ of the patients. The rate of control in BP was $82.4\%$ at 6 months. The major antihypertensive drugs prescribed were calcium channel blockers $(61.8\%)$ , ACE inhibitors $(19.1\%),\;\beta-blockers\;(13.7\%)$ and diuretics $(5.3\%)$ as the 1st-line monotherapy. The methods of treatment used as the 1st-line therapy were monotherapy$(59\%)$ and combination therapy $(41\%)$. Blood pressure change was significantly greater for combination therapy than monotherapy$(-26.2\pm21.4\;vs.\;-18.56\pm16.7$ mmHg for systolic blood pressure; P<0.003, $-16.9\pm13.2\;vs.\;-9.2\pm12.8$ mmHg for diastolic blood pressure; p<0.001). When blood pressure was not completely controlled with the first antihypertensive selected, the 2nd line therapy had 4 options: addition of 2nd agent from different class; $66.2\%$, substitution with another drug, $21.9\%$ increase dose $11.9\%$ continue first regimen $27.9\%$ Calcium channel blockers were the most frequently prescribed agents. This was not comparable to the JNC VI guideline which recommended diuretics and $\beta-blockers$ for the 1st-line therapy. Most of patients achieved the goal BP and maintained it until 6 months, but the remaining patients should be controlled more tightly to improve their BP with combination of life style modification, patient education, and pharmacotherapy.

• 지역사회간호학회지
• /
• 제12권1호
• /
• pp.226-238
• /
• 2001

This study was attempted to understand experiences of the users of natural family planning(NFP) by applying Q-methodology. 37 statements were used to Q population through literature research and interviews. For the P sample. I interviewed personally 30 people who had taken a lesson in NFP for over 6 months and had been using and experiencing it autonomously for more than 2 years so far, and asked them to Q-classify the statement cards in order of the degree of approval, from the one they most approved to the one they least approved. Data were coded and input into a computer and were analyzed using QUANL PC Program. In this study, I discovered 4 types of experiences by the users of NFP and named them each according to their features: the first, a type of mutual control with morality, the second, a type of the pursuit of mutual -cooperation, the third. a type of the pursuit of conviction. and the fourth, a type of the perception of health management. The first type said that NFP was a good contraceptive way in which no drug or devices are used, that the husband's cooperation was needed, and that they became able to control sexual desire with morality. The second type perceived that continuous efforts were required to put NFP in practice, that the, husband's cooperation was essential, and that dialogues between husband and wife were also necessary to use it, and as such they regarded mutual cooperation between husband and wife as highly important. On the other hand. the third type perceived that one's conviction played a big part, that knowledge of physiological changes was useful and the ability to sense physical changes improved. and that one's willpower was important. and thus they regarded one's own willpower as most important. The fourth type reported that this method was a good way to control pregnancy and should be taught about at the beginning of sex education. and thus they were emphasizing the importance of NFP as a helpful way to manage one's health. 1. therefore, intend to provide the following suggestions based on the result of this study. 1) It is necessary to develop a program that allows NFP to be applied to sex education program. 2) It is necessary to analyze factors that affect the execution of NFP. 3) It is necessary to analyze causes of failure of those who fail to execute NFP.

• 한국해양공학회지
• /
• 제19권5호
• /
• pp.43-49
• /
• 2005

This paper is to investigate the effect of corrosion by acoustic emission method in tensile loading and the adhesiveness between substrate and coating layer. The powders used are Zn and Amdry625, respectively. They are coated on brass alloy substrate. AE signals of Zn and Amdry625 coating layer increase drastically in strain $2\%$. However, those of Zn specimen have more than those of Amdry625 specimen. When the specimens executed the corrosion test under $3.5\%$ NaCl solution for 500, 1000 hours, the salt solution penetrated into the surface of the substrate through the pores of the coating layer. As a result, corrosion production formed on the surface of the substrate. The adhesiveness between coating layers is weakened by the polarization and corrosion itself. The AE event, count, and energy of corroded coating specimens decrease, compared to specimens without corrosion. The results are summarized as follows : 1. In the tensile tests, the time that it took to start and develop the cracks and exfoliations between the surface of the substrates and the plasma spray coatings were different according to the type of plasma sprayed material, which are Zn and Amdry625. These phenomena were obvious at the strain rate 1 to $5\%$, and few available data were found after that stage. 2. The specimens with Zn coating showed the characteristics of crack, according to the changes of the tensile strength applied on the substrates while those with Amdry625 showed exfoliation as a result of low adaptation to the tensile strength. 3. The anti-corrosion specimens showed that the adhesive properties between the substrate and the plasma spray coating were strong in the order of Zn, Amdry. It showed that Corroded specimens cracked or exfoliated easily, even with the small energy, because those had a comparatively weakened adhesive property, due to corrosion. 4. Zn specimen showed no corrosion phenomena on the surface of the substrates, because they had the function of sacrifice anode however, Amdry625 specimen showed the corrosion, because it did not have that function.