• Structural Engineering and Mechanics
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• 제21권5호
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• pp.539-551
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• 2005

Finite elements based on isoparametric formulation are known to suffer spurious stiffness properties and corresponding stress oscillations, even when care is taken to ensure that completeness and continuity requirements are enforced. This occurs frequently when the physics of the problem requires multiple strain components to be defined. This kind of error, commonly known as locking, can be circumvented by using reduced integration techniques to evaluate the element stiffness matrices instead of the full integration that is mathematically prescribed. However, the reduced integration technique itself can have a further drawback - rank deficiency, which physically implies that spurious energy modes (e.g., hourglass modes) are introduced because of reduced integration. Such instability in an existing stiffness matrix is generally detected by means of an eigenvalue test. In this paper we show that a knowledge of the dimension of the solution space spanned by the column vectors of the strain-displacement matrix can be used to identify the instabilities arising in an element due to reduced/selective integration techniques a priori, without having to complete the element stiffness matrix formulation and then test for zero eigenvalues.

• 가정과삶의질연구
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• 제21권4호
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• pp.103-116
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• 2003

The purpose of this study was to examine the economic status of retired elderly households. This study especially looked for the differences in the economic status among retired elderly households and the level of subjective financial strain. The data were drawn from the data of 2000 Korean Labor and Income Panel Study (KLIPS) conducted by the Korea Labor Institute. The major findings are as follows: 1) The levels of income in the retired households were found to be lower than those of the employed elderly households, and the transfer income took the biggest portion out of 5 income types reflecting high economic dependency. 2) The levels of expenditure were found to be similar to the minimum living cost, and the food cost at home was 41.9% of the expenditure. 3) About 40% and 27.3% of households reported that they felt financial strain due to food expenditures at home and health care respectively. 4) Ninety percent of all assets were found to be real estate, reflecting the lack of asset liquidity. Further, retired elderly households were classified as 'not at all strained financially', 'moderate', 'seriously strained', and 'extremely strained' groups according to their subjective assessment. The last two groups showed the lower level of income and expenditures than the first two groups. In particular, 26.5% of retired elderly households belonged to 'extremely strained' group and showed very serious economic problems.

• Geomechanics and Engineering
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• 제16권6호
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• pp.627-634
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• 2018

Soil stabilization is an essential engineering process to enhance the geotechnical properties of soils that are not suitable for construction purposes. This study focuses on using coconut coir, a natural fibre to enhance the soil properties. Lime, an activator is added to the reinforced soil to augment its shear strength and durability. An experimental investigation was conducted to demonstrate the effect of coconut coir fibers and lime on the consistency limits, compaction characteristics, unconfined compressive strength, stress-strain behaviour, subgrade strength and durability of the treated soil. The results of the study illustrate that lime stabilization and coir reinforcement improves the unconfined compressive strength, post peak failure strength, controls crack propagation and boosts the tensile strength of the soil. Coir reinforcement provides addition contact surface, improving the soil-fibre interaction and increasing the interlocking between fibre and soil and thereby improve strength. Optimum performance of soil is observed at 1.25% coir fibre inclusion. Coir being a natural product is prone to degradation and to increase the durability of the coir reinforced soil, lime is used. Lime stabilization favourably amends the geotechnical properties of the coir fibre reinforced soil.

• 대한화장품학회지
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• 제41권4호
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• pp.375-382
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• 2015

진세노사이드(인삼 사포닌)는 인삼의 대표적 약리성분 중의 하나로 생물학적 활성을 가진 배당체 화합물이다. 이들 사포닌은 가수분해 되어 저분자화 되었을 때, 항주름 및 항산화, 항암 등에 높은 약리효능효과를 나타낸다. 본 연구에서는 인삼 esculin 배지를 활용하여 ${\beta}$-glucosidase 활성을 가진 균주를 분리하였고 인삼 사포닌 전환을 미생물을 이용하여 수행하였다. 본 균주들을 16S rRNA sequencing을 통하여 동정하여 본 결과 Stenotrophomonas rhizopilae strain GFC09로 확인되였다. 균주의 최적 활성 조건을 결정하기 위해 조효소 1 mM와 인삼사포닌 $Rb_1$과 함께 배양한 후 생물학적 전환을 TLC, HPLC를 사용하여 확인하였다. 조효소에 의한 인삼 사포닌 $Rb_1$의 전환 경로는 다음과 같다. LB: RbNeobio R&D center, Gyeonggi-do 16954, Korea${\rightarrow}$Rd${\rightarrow}$FNeobio R&D center, Gyeonggi-do 16954, Korea${\rightarrow}$compound K, TSB: $Rb_1{\rightarrow}Rd{\rightarrow}F_2$. 가수분해된 생성된 물질은 NMR로 구조 동정하였다. 전환 산물의 효능 분석결과, 콜라겐 생성을 농도 의존적으로 증가시키는 것이 관찰되었다. 이에 본 연구에서는 ginsenoside $F_2$와 compound K 함유 인삼 전환 산물의 주름 개선 소재로서 활용가능성을 확인하였다.

• Tuberculosis and Respiratory Diseases
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• 제61권1호
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• pp.13-19
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• 2006

연구 배경: A. baumannii는 전 세계적으로 중요한 병원 내 병원균으로 부각되고 있고 이들 균에 의한 감염 또한 빠르게 증가하고 있다. 이들 감염에 연관된 사망률(균혈증:52%, 폐렴:23-73%)은 매우 높고 다제 내성은 비교적 흔하게 발생하고 있는 실정이다. 그러므로 다제 내성 A. baumannii 감염에 대한 효과적인 치료를 위해서 이들의 임상 특징과 결과를 분석하고 이해하는 것이 필요하다. 이에 본 연구는 A. baumannii 병원내 폐렴 중 다제 내성군과 약제 감수성군 간의 임상적 특징, 사망률, 이환율을 비교하였다. 방 법: 2002년 1월 1일부터 2004년 11월 1일까지 춘천성심병원에 입원했던 환자 중 Acinetobacter 병원 내 폐렴으로 판단되는 47명의 환자를 연구 대상으로 하였고 이들의 의무기록을 후향적으로 분석하였다. 본 연구에서는 다제 내성 A. baumannii를 실험 환경에서 A. baumannii에 효과적이며 상업적으로 이용할 수 있는 모든 항생제에 내성을 보이는 것으로 정의하였다. 결 과: 47명의 A. baumannii 병원내 폐렴 환자 중 17명이 다제 내성군, 30명이 약제 감수성군으로 분류되었다. 이들의 평균 연령은 다제 내성군은 $69{\pm}11$세, 약제 감수성군 $70{\pm}13$세이었고 APACHE II 점수, 중환자실 입원기간, 사망률에 있어서 두 군간에 유의한 차이는 없었다($16.1{\pm}5.4$ vs $14.9{\pm}4.8$, P=0.43, $25.1{\pm}13.6$ vs $39.1{\pm}31.0$, P=0.2, 58.8% vs 40%, P=0.21). 결 론: Acinetobacter baumannii 다제 내성군과 약제 감수성군 간의 사망률과 임상적 특징 사이에서 유의한 차이는 보이지 않았다. 그러나 양군 모두 사망률과 이환율은 높게 나타나 A. baumannii 감염의 효과적인 감시 및 조절이 지속적으로 필요하겠다.

• 한국임상보건과학회지
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• 제3권1호
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• pp.290-298
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• 2015

Purpose. This study aimed to explore family caregivers' experiences with ventilator-dependent patients at home. Methods. The number of patients using mechanical ventilators at home is expected to increase and family caregivers must be able to care for them. However, few studies focus on the experiences of family caregivers. We conducted in-depth interviews with 11 family caregivers who cared for a ventilator-dependent patient at home in South Korea. Data were analyzed using phenomenological method of enquiry. Results. Statements generated from the interviews on the meaning of the family caregiver's experiences were organized into 27 themes, 5 theme clusters, and 2 categories. The theme clusters included endurance under the burden situation, role strain as a caregiver, separation from others, trying to find coping methods, and oriental ethnical customs. Family caregivers of patients using domestic mechanical ventilators need systematic education and emotional support to cope with the challenges of managing ventilator equipment and learning new ways of communicating with patients on the ventilators. Conclusion. These findings may contribute to family caregivers' knowledge and competence, thereby allowing them to better support their ventilator-dependent family members.

• 부모자녀건강학회지
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• 제14권1호
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• pp.36-44
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• 2011

Purpose: This study was conducted to explore foreign immigrant mothers' experiences of pregnancy, childbirth, and child rearing. Methods: Ten married female migrants were selected by a purposive and snowball sampling method. Data were collected during the period from September to November, 2009 by individual in-depth interviews and all interviews were audio-taped and transcribed verbatim. Results: Ten categories were induced: In pregnancy and childbirth domain, social support-request help to their own parents, social support-depending on husband and mother's in law, Enduring emesis-gravidarum in strange environment were extracted. In Chid-rearing domain, child-rearing overburden, lack of self-confidence on maternal role, child-rearing difficulties due to language barrier, lack of information and education on child-rearing, lack of accessibility to public health care services, expectation of child's assimilation in Korea, financial strain in child-rearing. Conclusion: This study provides basic knowledge regarding married female migrants' experiences related to pregnancy, childbirth, and child rearing. The findings of the study will help health professionals designing effective interventions for married female migrants with difficulties related to child care, parenting, rearing.

• 한국전산구조공학회논문집
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• 제28권4호
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• pp.401-408
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• 2015

기존 구조물의 모델 업데이팅 기법은 주로 진동 계측을 통해 얻은 전역적 구조 응답-모달 파라미터-를 이용한다. 모달 파라미터를 이용하여 업데이트된 모델은 전역적 구조 응답을 잘 추정할 수 있지만, 부재 레벨의 안전성 평가를 위한 국부적 응답 예측에는 어려움이 있다. 구조물 내 구조 부재들의 변형률 계측을 통해 응력을 추정하고, 안전성 평가가 이루어진다. 따라서, 본 연구는 모달 파라미터 이외에 로컬 구조 부재들에 가하는 해머 가력을 통해 계측한 변형률을 추가적으로 모델 업데이팅에 이용한다. 본 연구가 제안하는 모델 업데이팅에서 목적함수는 전역적/국부적 계측 응답과 모델의 응답간의 차로 설정되며 NSGA-II를 이용하여 이를 최소화된다. 업데이트 모델에서 예측하는 변형률 응답은 철골조의 안전성 평가에 활용된다. 제안한 기법은 철골 프레임에 대한 시뮬레이션과 해머 가력 실험을 통해 검증된다.

• 콘크리트학회논문집
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• 제11권6호
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• pp.3-12
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• 1999

The larger, loftier and more highly strengthened the recent structures become, the greater attention is paid to the problem of thermal crack occurrence associate with hydration heat. As one of methods to solve the problem, a care has been taken to the improvement of construction such as the application of pre-cooling or pipe-cooling, adjustment of concrete block size, concrete placement timing, joint arrangement and so on. But it is expected that a proper selection of cement shall additionally contribute to the control of thermal cracks. In this study, thus, we selected 4 types of cements such as Type V for anti-sulphate, blast furnace cements (slag content of 45% and 65% respectively)and ternary blended low heat cement, and carried out mock-up tests. In every assigned time, temperatures and thermal stresses were measured and calculated from raw data. As a result of measurement, it was found that the magnitude of hydration heat is in order of blast furnace slag cement. Type V and ternary blended low heat cement. Results of thermal stresses were same as the order of temperature. In addition, thermal stresses calculated from the data of strain gauges showed almost similar to those measured from effective stress gauges only when strain values were adjusted properly in accordance with initial time of stress appearance. Theoretical results agreed well with the measured values comparatively, but showed slight differences. It is inferred that these differences shall be reduced if more tests capable of evaluating thermal characteristics of concrete are carried out.

• Tuberculosis and Respiratory Diseases
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• 제75권2호
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• pp.75-78
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• 2013

Methcillin-resistant Staphylococcus aureus (MRSA) has emerged as an important cause of community-acquired infections, which has been recently designated as community-associated (CA) MRSA. Panton-Valentine leukocidin (PVL)-negative multilocus sequence type 72 (ST72)-staphylococcal cassette chromosome mec (SCCmec) type IV has been reported as the predominat CA-MRSA strain in Korea and is commonly associated with skin and soft tissue infections in addition to healthcare-associated pneumonia. However, community-acquired pneumonia (CAP) for this strain has not yet been reported. We hereby report two cases of CAP caused by PVL-negative ST72-SCCmec type IV strain in patients who had no risk factors for MRSA acquisition. While CA-MRSA infections are not yet prevalent in Korea, our cases suggest that CA-MRSA should be considered in cases of severe CAP, especially for cases associated with necrotizing pneumonia.