• 제목/요약/키워드: Risk function

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토석류 유동해석을 위한 유한요소 수식화 (FEM Numerical Formulation for Debris Flow)

  • 신호성
    • 한국지반공학회논문집
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    • 제30권10호
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    • pp.55-65
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    • 2014
  • 최근 토석류의 이동 메커니즘에 대한 연구와 거동 예측을 위한 해석 프로그램의 개발이 활발히 진행중이다. 하지만, 토석류를 유체이동으로 간주하는 기존의 프로그램들은 수치적인 안정성과 모델링 그리고 다양한 경계조건의 적용에 대한 제약이 있다. 본 연구에서는 토석류의 유동현상에 대한 연속방정식과 힘평형 방정식에 대하여 깊이적분을 수행하였다. 토체의 두께 h, x와 y 흐름방향의 평균속도 $\bar{u}$, $\bar{v}$를 주변수로 채택하여 흐름이 없는 해석영역에 대한 수치적인 안정성을 확보하였다. DG기법에 의한 가중행렬을 산정하고 유동방향을 고려한 불연속 시험함수를 이용하여 Petrov-Galerkin 수식화를 수행하였다. 그리고 토석류의 유체 및 토립자의 특성을 동시에 고려할 수 있는 역학적 구성모델을 제시하였다. 단일경사 사면에서 사면경사, 토사 유발량, 저면 마찰 저항이 토석류 흐름특성에 미치는 영향을 비교 분석하였다. 그리고 수치해석을 통하여 사면 하부에 설치된 제방의 영향을 분석하였다. 개발된 해석프로그램을 활용하여 토석류 발생예상 지역의 다양한 위험인자에 대한 평가를 수행하고, 피해를 최소화하기 위한 시설물의 설계방안을 제안할 수 있을 것으로 판단된다.

Dipyridamole 부하를 T1-201 심근스캔에서 폐/심장 섭취율과 일과성 좌심실 확장율에 관한 연구 (Lung/Heart Uptake Ratio and Transient Dilation Ratio of the Left Ventricle During Thallium-201 Imaging with Dipyridamole)

  • 이재태;정병천;김상현;이규보;채성철
    • 대한핵의학회지
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    • 제25권2호
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    • pp.177-185
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    • 1991
  • Dipyridamole thallium imaging is one of the most widely accepted means of evaluating patients with suspected or known coronay artery disease. The results of thallium imaging help diagnose coronary artery disesse (CAD), determine the hemodynamic significance of coronary stenosis, evaluate viability of myocardium, assess the outcome of therapeutic interventions and stratify patients according to their risk for luther cardiac events. An increased lung thallium uptake and transient LV dilation has been reported as poor prognostic indicator and associated with extensive and severe coronary artery disease. We quantitated lung/heart uptake ratio (l/HUR) and transient left ventricular dilation ratio in 44 patients and 17 controls undertaking dipyridamole thallium-201 scintigraphy. The results are as follows: 1) The lung/heart uptake ratio was high in patients with CAD and which became higher according to increasing number of diseased vessel. The L/HUR of patients with low LVEF (<35%) was lower than those with normal LVEF. 2) Transient left ventricular dilation ratio of CAD patients had no close relation between numbers of diseased vessels and was not higher than normals. But transient left ventricular dilation ratio of patients with myocardial infartion was higher than normals. We concluded that lung/heart uptake ratio seems to be sensitive marker for severity of CAD and myocardial function, but transient left ventricular dilation ratio alone is not sufficient to be a marker for severe and extensive CAD.

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강재 절단용 장약용기를 이용한 철골 교량 발파해체 시공사례 (Case Study on the Explosive Demolition of Steel Truss Bridge using Charge Container for Cutting Structural Steel)

  • 박훈;석철기;노유송
    • 화약ㆍ발파
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    • 제36권1호
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    • pp.20-33
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    • 2018
  • 국부손상 구조물은 내 외부에서 발생하는 비정상 하중에 의해 구조물 일부가 구조적 기능을 상실하여 재사용이 불가능한 구조물이다. 비정상 하중의 발생 원인으로는 자연재해와 인공재해로 대별되며 이러한 비정상 하중에 의해 발생한 국부손상 구조물은 추가적인 2차 붕괴의 위험요소들을 내재하고 있어 신속한 전면해체가 요구된다. 본 시공사례는 건설실패 및 태풍으로 피해를 입은 필리핀의 철골 트러스 구조의 교량에 대해 발파해체를 적용한 사례이다. 발파해체를 위해 성형폭약의 사용이 필요하나 현지에서 수급이 불가하여 장약용기를 제작한 후 용기 속에 에멀전계열 폭약을 충전하여 발파해체에 적용하였다. 발파해체 결과 교량의 중앙부가 수직 자유낙하하고, 교량 끝단이 지지부를 중심으로 회전하면서 자유낙하 하였다. 교각 및 주변에 피해가 발생하지 않았으며, 발파 후 철거대상부의 파쇄 상태는 매우 양호하였다.

해조류 유래 호흡기 질환 천식 치료제 연구 동향 (A Review of Marine Algae-derived Therapeutic Agents for Respiratory Disease Asthma)

  • 김태희;허성영;오건우;김민성;최일환;정원교
    • 한국해양바이오학회지
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    • 제12권1호
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    • pp.1-10
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    • 2020
  • Asthma is a complex inflammatory disease of the lung characterized by variable airflow obstruction, airway hyperresponsiveness, airway inflammation, and reduction of respiratory function. Its prevalence and incidence are increasing because of the effect of various environmental and lifestyle risk factors. Steroid inhalation, long-acting agonists, and other synthetic drugs are used for the treatment of this disease. However, they have some side effects and show unsatisfied result and response after treatment. Therefore, many researchers have focused on the development of natural product-related treatment for asthma to suppress the side effects and unsatisfied results. Seaweeds contain various bioactive compounds with anti-inflammatory, antibacterial, and anti-oxidant activities. Thus, we investigated the asthma treatment-related literature using marine algae via the Google scholar search engine. Consequently, the literature is rarely investigated, but is increasing steadily. The literature was performed as a comparison study with an ovalbumin-induced group or drug-treated group, and investigated the antiasthma activity of algae ethanol extract. Although many researchers have studied marine algae-derived therapeutic agents for asthma, the amount of literature is rare compared with those of herbal medicine-derived therapeutic agents. Conclusively, we suggest that many researchers should investigate and develop algae-derived therapeutic agents for asthma treatment.

추간판이 물리적 자극의 수용기 역할을 하는 경우 기립 상태에서 복압 및 복근의 역할이 척추 안전성에 미치는 영향 (Effects of Abdominal Muscle and Pressure on the Spine Stability during Upright Stance Posture - For the Case where Intervertebral Disc Plays the Role of Mechanoreceptor)

  • 최혜원;김영은
    • 한국정밀공학회지
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    • 제28권1호
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    • pp.115-122
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    • 2011
  • Recently, we have proposed a hypothesis that spinal structures have a stress sensor driving feedback mechanism, In the human spine, spinal structure could react to modify muscular action in such a way so as to equalize stress at the disc, therefore reduce the risk of injury, In this analysis, abdominal muscle and abdominal pressure, which were not included in the previous study, were added to identify those effects in spine stability during upright stance posture for the case where the intervertebral disc plays the role of mechanoreceptor, The musculoskeletal FE model was consisted with detailed whole lumbar spine, pelvis, sacrum, coccyx and simplified trunk model. Muscle architecture with 46 local muscles containing paraspinal muscle and 6 rectus abdominal muscles were assigned according to the acting directions. The magnitude of 4kPa was considered for abdominal pressure. Minimization of the nucleus pressure deviation and annulus fiber average tension stress deviation was chosen for cost function. Developed model provide nice coincidence with in-vivo measurement (nucleus pressure). Analysis was conducted according to existence of co-activation of abdominal muscle and abdominal pressure. Antagonistic activity of abdominal muscle produced stability of spinal column with relatively small amount of total muscle force. In contrast to the abdominal muscle, effect of abdominal pressure was not clear that was partly depending on the assumption of constant abdominal pressure.

The Effects of Actual and Perceived Body Weight on Unhealthy Weight Control Behaviors and Depressed Mood among Adult Women in Seoul, Korea

  • Kim, Dong-Sik;Kim, Hyun-Sun;Cho, Young-Tae;Cho, Sung-Il
    • Journal of Preventive Medicine and Public Health
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    • 제41권5호
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    • pp.323-330
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    • 2008
  • Objectives : This study was conducted to examine the mediating function of body weight perception (BWP) on the relationship between body mass index (BMI) and unhealthy weight control behaviors (UWCB: e.g., fasting, or taking diet pills or laxatives) and between BMI and depressed mood, and to explore the effect of distorted BWP on UWCB and depressed mood among adult women. Methods : A regionally representative sample of 8,581 women aged 20-64 years residing in Seoul, the capital of Korea, completed the 2001 Seoul Citizens Health Indicator Survey which provides self-reported information about height, weight, BWP, UWCB, depressed mood, demo graphic/socioeconomic characteristics, and health-related behaviors. Data were analyzed using bivariate and multivariate logistic regression. Results : BMI was significantly associated both with UWCB and depressed mood, even controlling for all covariates. However, the magnitude and significance of each association was considerably attenuated when BWP was taken into account, indicating that BWP functioned, in part, as a mediator between BMI and UWCB and between BMI and depressed mood, respectively. Among the combinations of BMI and BWP, women who perceived themselves to be heavier than their actual BMls appeared more likely to use UWCB, whereas women who had a distorted BWP, either underestimation or overestimation as compared with their BMIs, tended to be at greater risk for depressed mood than those who had an undistorted BWP. Conclusions : These findings suggest that how women perceive their body weight may be an important predictor and/or mediator of UWCB and depressed mood among adult Korean women.

소아청소년기 당뇨병성 신병증(I); 임상 소견을 중심으로 (Diabetic Nephropathy in Childhood and Adolescence (I) : Clinical Features)

  • 하태선
    • Childhood Kidney Diseases
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    • 제13권1호
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    • pp.1-13
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    • 2009
  • 소아청소년기의 당뇨병은 대부분 제1형 당뇨병이나 최근 우리나라를 포함한 서구 사회에서는 제2형 당뇨병의 빈도가 증가하고 있다. 임상소견 상 제1형 당뇨병은 여러 위험인자에 의하여 비교적 전형적인 단계를 거치면서 미세알부민뇨와 당뇨병성 신병증으로 진행하면서 만성 신질환으로 발전하게 되며, 제2형 당뇨병은 비전형적 임상경과를 거치나 신병증 진행율이 높아서, 실제로 당뇨병성 신병증은 전세계 신장대체요법이 필요한 말기 신질환의 가장 많은 원인이며 국내에서도 꾸준히 원인 질환으로서 증가 중이다. 당뇨병이 사춘기 전에 발생하는 경우보다 사춘기나 그 이후에 발생하는 경우에 혈관합병증의 발생이 증가하므로, 사춘기가 위험인자로 작용하며, 이것은 유병기간과 함께 사춘기 전에 소아 당뇨병성 신병증이 발생하는 경우는 매우 드문 이유이다. 제1형과 제2형 당뇨병에서 신병증은 비슷하게 15-25%에서 발병하며, 당뇨병성 신병증과 만성 신질환으로 진행하는 과정 중에 가장 중요한 표식자인 미세알부민뇨는 위험인자이고 병리학적 소견과 관련이 있다.

SIL(Safety Integrity Level) 선택에 의한 리스크 감소에 관한 연구 (A Study of Risk Reduction by SIL(Safety Integrity Level) Determination)

  • 김정환;김범수;양재모;장창봉;김민섭;정상용;고재욱
    • 한국가스학회지
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    • 제15권5호
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    • pp.57-62
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    • 2011
  • 현대의 화학공장 및 석유 가스산업 시설은 공정 및 설비가 더욱 복잡해지고 세분화됨으로써 산업현장에서는 다양한 잠재위험으로 인하여 화재, 폭발, 독성물질 누출 등의 중대 산업사고의 발생 가능성 및 사고결과의 피해가능 범위가 증가되고 있다. 이러한 위험요소를 줄이기 위하여 공정 내 안전장치를 설치하여 공정의 위험도를 줄여야 하지만, 공장 운전 효율성과 안전도는 서로 적절한 수준을 유지하지 않으면 잦은 검사와 확인으로 효율성을 저해할 수 있다. 그를 위하여 이번 연구에서 SIL(Safety Integrity Level)을 이용한 SIF(Safety Instrument Function)의 추가로 장치의 적절한 사양, 설계를 이루고 공정내의 잠재위험이 사고로 이어지는 것을 방지하여, 화학공장의 안전성을 향상시켰다.

미국에서 노인을 위한 "스마트홈(SmartHome)" 개념의 요소와 적용 (Elements and Application of "SmartHome" Concept for Older Adults in USA)

  • 문창호
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제17권4호
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    • pp.7-14
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    • 2011
  • This paper is intended to suggest some reference materials for future elderly housing design, especially smart home, in Korea, by reviewing the elements and applications of smart home concept for older adults in USA. Research method includes collecting materials by attending the regular SmartHome$^{(R)}$ part meeting, the navigation of related homepages, and the analysis of collected materials. Current researches in Korea look initial stage and show some general principles without practical concept & technologies of elderly facilities. SeniorSmart$^{(R)}$ Center in USA started on August 2007 with the 3 parts of SmartHOME$^{(R)}$, SmartWHEELS$^{(R)}$ and SmartBRAIN$^{(R)}$. The Center has been doing various multidisciplinary research projects but slowing down the planned processes due to national economic recession. The major researches of SmartHome$^{(R)}$ part can be summarized as follows; CS-PFP( Continuous Scale Physical Function Performance) laboratory is being in operation to help older adults and families make the difficult decision regarding the ability and safety to live independently. Three levels of necessary laboratories from uninhabited space to senior living environment were accommodated for field research. As core technologies of SmartHome$^{(R)}$, predicting & warning system of fall risk on recognizing gait signature patterns to identify any deviation from the normal patterns of the older adults, home monitoring system which will send alerts to a specified relative and/or health care professional when vital signs of the older adults will not be within normal parameters, and Mobility & Research Clinic for evaluating, treating the older adults & multidisciplinary research are under development. SmartHome$^{(R)}$ has made collaborative research agreements for field laboratory with various retirement communities and also is continuing to work for experimental software engineering with the Fraunhofer Institute, Germany.

신선초 녹즙섭취가 흡연자의 지질 수준 및 혈장 항산화 비타민 영양상태에 미치는 영향 (The Effects of Green Vegetable Juice (Angelica Keiskei) Supplementation on Plasma Lipids and Antioxidant Status in Smokers)

  • 김정신;김혜영;박유경;김태석;강명희
    • Journal of Nutrition and Health
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    • 제36권9호
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    • pp.933-941
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    • 2003
  • It has been suggested that green juice supplementation may have some health promoting benefits. We evaluated the effects of green juice (Angelica keiskei) consumption on parameters of lipid profiles and plasma antioxidant status in healthy male smokers. Fifty-four smokers were supplemented with 300 ml of green juice for 6 weeks while maintaining their normal diet. Blood samples were collected on week 0 and week 6 in order to evaluate plasma lipid profiles (total cholesterol, triglyceride, LDL-cholesterol, HDL-cholesterol) , plasma antioxidant vitamin levels (ascorbic acid, $\alpha$ -tocopherol, ${\gamma}$ -tocopherol, $\alpha$ -carotene, $\beta$ -carotene, cryptoxanthin and lycopene) , the degree of LDL oxidation and GOT, GPT levels for liver function. Plasma ascorbic acid level remained at the same level. However, $\alpha$ -tocopherol and ${\gamma}$ -tocopherol normalized by total cholesterol (p <0.05) and $\beta$ -carotene (p <0.001) level were all significantly increased after green juice supplementation. Plasma cholesterol was reduced for 12%, LDL-cholesterol was reduced for 9.3% after green juice consumption, while plasma triglyceride and HDL-cholesterol was not changed. Oxidized LDL assessed by conjugated diene (CD) , was decreased (p < 0.0001) after green juice consumption. These results further support a role for green juice supplementation in the improvement of lipid status, prevention of lipid peroxidation, and thereby reducing risk factors of numerous diseases associated with elevated oxidative stress in smokers.