• 전기학회논문지
• /
• 제58권7호
• /
• pp.1375-1379
• /
• 2009

Insulation tests have been performed on two generator stator bars under accelerated aging under a laboratory environment. Electrical stress was applied to stator bar No.1, and electrical and thermal stresses were applied to stator bar No.2. Nondestructive stator insulation tests including the ac current, dissipation factor($tan{\delta}$), and partial discharge tests have been performed on both bars as the bars were aged for 11460 hours. Experimental test results show that ${\Delta}I$, ${\Delta}tan{\delta}$, and partial discharge of No. 1 and No.2 stator bars increased with increased in aging time. It has been concluded from the test that the stator insulation of the two generators are in good condition.

• Journal of Computing Science and Engineering
• /
• 제2권2호
• /
• pp.200-219
• /
• 2008

The effective management of uncertainty is one of the most fundamental problems in medical decision making. According to the literatures review, most medical decision models rely on point estimates for input parameters. However, it is natural that they should be interested in the relationship between changes in those values and subsequent changes in model output. Therefore, the purpose of this study is to identify the ranges of numerical values for which each option will be most efficient with respect to the input parameters. The Nonhomogeneous Poisson Process(NHPP) was used for describing the behavior of aging chronic diseases. Three kind of failure models (linear, exponential, and power law) were considered, and each of these failure models was studied under the assumptions of unknown scale factor and known aging rate, known scale factor and unknown aging rate, and unknown scale factor and unknown aging rate, respectively. In addition, this study illustrated developed method with an analysis of data from a trial of immunotherapy in the treatment of chronic Granulomatous disease. Finally, the proposed design of Bayesian value of information analysis facilitates the effective use of the computing capability of computers and provides a systematic way to integrate the expert's opinions and the sampling information which will furnish decision makers with valuable support for quality medical decision making.

• 한국노년학
• /
• 제36권4호
• /
• pp.1075-1088
• /
• 2016

본 연구는 고령자의 활동적 노화가 삶의 만족도에 미치는 영향요인을 분석하여, 고령자의 삶의 만족도를 향상시키기 위한 활동적 노화 증진방안을 모색하는데 목적을 두고 있다. 이를 위해 활동적 노화를 건강요인, 참여요인 및 보장요인으로 구분하고 국민노후보장패널 자료를 활용하여 55세 이상의 가구원 총 5,501명을 최종분석 대상으로 위계적 회귀분석을 실시하였다. 분석결과 고령자의 활동적 노화가 삶의 만족도에 미치는 영향에 대한 설명력은 34%로 나타났으며, 고령자의 활동적 노화 요인 중에서 건강요인인 주관적 건강상태와 심리적 건강상태, 참여요인인 노동시장의 참여 유무 및 보장요인인 소득수준과 주거보장이 삶의 만족도에 영향을 미치는 것으로 확인되었다. 활동적 노화 요인 중에서 삶의 만족도에 영향을 미치는 결정요인은 건강요인으로 확인되었으며, 이중에서도 주관적 건강상태가 삶의 만족도를 가장 많이 설명하는 결정요인으로 나타났다. 따라서 고령자의 활동적 노화를 촉진하고 삶의 만족도를 높이기 위해서는 고령자의 신체적 정신적 건강증진, 노동시장 참여 및 주거보장을 위한 국가적 지역적 차원의 다양한 정책 및 실천이 추진되어야 할 것이다.

• Tuberculosis and Respiratory Diseases
• /
• 제83권2호
• /
• pp.107-115
• /
• 2020

Aging is often viewed as a progressive decline in fitness due to cumulative deleterious alterations of biological functions in the living system. Recently, our understanding of the molecular mechanisms underlying aging biology has significantly advanced. Interestingly, many of the pivotal molecular features of aging biology are also found to contribute to the pathogenesis of chronic lung disorders such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis, for which advanced age is the most crucial risk factor. Thus, an enhanced understanding of how molecular features of aging biology are intertwined with the pathobiology of these aging-related lung disorders has paramount significance and may provide an opportunity for the development of novel therapeutics for these major unmet medical needs. To serve the purpose of integrating molecular understanding of aging biology with pulmonary medicine, in this review, recent findings obtained from the studies of aging-associated lung disorders are summarized and interpreted through the perspective of molecular biology of aging.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2008년도 춘계학술대회 논문집
• /
• pp.173-174
• /
• 2008

• Molecules and Cells
• /
• 제45권11호
• /
• pp.763-770
• /
• 2022

Caenorhabditis elegans has been used as a major model organism to identify genetic factors that regulate organismal aging and longevity. Insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) regulates aging in many species, ranging from nematodes to humans. C. elegans is a nonpathogenic genetic nematode model, which has been extensively utilized to identify molecular and cellular components that function in organismal aging and longevity. Here, we review the recent progress in the role of IIS in aging and longevity, which involves direct regulation of protein and RNA homeostasis, stress resistance, metabolism and the activities of the endocrine system. We also discuss recently identified genetic factors that interact with canonical IIS components to regulate aging and health span in C. elegans. We expect this review to provide valuable insights into understanding animal aging, which could eventually help develop anti-aging drugs for humans.

• 한국노년학
• /
• 제29권1호
• /
• pp.117-134
• /
• 2009

본 연구의 목적은 노인들에게 맞는 건강한 노후에 관한 안정적인 신뢰도와 적절한 타당도를 갖춘 척도를 개발하는 것이다. 서울에 거주하고 노인복지관을 다니며, 정기적으로 운동을 하고 있는 노인 전체 335명(예비 척도 개발에 65세 이상의 노인 127명, 1차 본 조사 척도 개발에 62명, 2차 본 조사 척도 개발에 146명을 대상)을 대상으로 하였고, 건강한 노후에 관한 개방형 질문지와 개발된 건강한 노후 척도를 통해 설문지의 타당도와 신뢰도를 검증하였다. 조사기간은 2006년 6월 12일부터 2006년 10월 27일까지 실시되었고, 자료처리는 Window용 SPSS 통계 Package 12.0 Version을 이용하여 평균, 표준편차, 첨도, 왜도, 신뢰도 분석, 탐색적 요인 분석, 확인적 요인분석을 실시하였다. 연구의 결과는 다음과 같이 나타났다. 첫째, 구성 개념 틀에 근거하여 만들어진 25개의 문항들에 대해서는 노인관련 전공교수 1명, 노인 여가학 박사 2명 등의 자문집단을 통해 내용타당도를 높였다. 둘째, 탐색적 요인분석 결과 건강한 노후 척도는 신체적 건강(6문항), 인지·정신적 건강(6문항), 사회·지지적 건강(8문항)의 3개의 하위요인으로 추출되었다. 셋째, 신뢰도 검사 결과 전체 문항에 대한 Cronbach's α는 .891로 높은 신뢰도를 보였고, 요인별 설문지의 내적 일관성 검정 결과는 각각 .642에서 .885의 범위를 나타냈다. 넷째, 확인적 요인분석 결과 본 연구에서 적합지수로 판단한 NFI, RFI, CFI, Delta 2 IFI값들 은 1에 가깝게 나타났다. 따라서 본 연구에서 결과로 도출된 타당도와 신뢰도의 결과들을 살펴봤을 때, 개발된 건강한 노후에 대한 설문지는 예비조사, 본 조사의 과정을 거쳐 확인된 신뢰도와 타당도가 이론적 기준에 벗어나지 않은 적절한 도구이며, 특히 노인들의 건강한 노후 생활에 대한 기준과 틀을 제시한다는 점에서 그 의의가 있다고 하겠다.

• 한국전기전자재료학회논문지
• /
• 제27권1호
• /
• pp.27-32
• /
• 2014

In this paper, PZT piezoelectric ceramic specimens with 4 compositions (Zr/Ti=50/50, 53/47, 56/44, 58/42) in $Pb(Zr,Ti)O_3$ system were fabricated. We studied effects of poling strength and thermal aging on the temperature characteristics of eletromechanical coupling factor k31 of the specimens, which were poled with the DC electric fields, 1.5, 2.5 and 3.5 kV/mm respectively and thermally aged for an hour at $200^{\circ}C$. The eletromechanical coupling factor k31 of the specimen with the composition Zr/Ti= 53/47, nearest to the morphotropic phase boundary decreased the most greatly, irrelevant to the intensity of poling field, due to 1st thermal aging. And the temperature coefficient of eletromechanical coupling factor k31 was (-) in the tetragonal phase composition and (+) in the rhombohedral phase composition, which is reverse in the temperature coefficient of resonance frequency. It is interesting that eletromechanical coupling factor k31 of PZT ceramics is shown to be able to increase as temperature increase in the interval $-20{\sim}80^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
• /
• pp.82-86
• /
• 2004

This research is about the result of leakage current waveform about the situation of surface leakage current and environmental changes(Salt fog, clean fog and rain) by EPDM polymer insulators' amount of salt. The researcher presents the result of changing about fundamental harmonic, 3rd harmonic and 5th harmonic from starting point of supplying power to flashover. In this study, researched environmental affects (clean fog, salt fog and rain) about surface aging of polymer insulators and used frequency spectrum of leakage current waveform to develop the diagnostic technique of surface aging. When amount of salt contents changed, surface aging stage and the degree of aging (distortion factor) about 3rd and 5th harmonic waveform on low frequency harmonic wave. The distortion factor which is harmonic percentage about basic harmonic is important pointer to evaluate the surface condition of polymer insulators.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권3호
• /
• pp.1098-1112
• /
• 2018

Achievable sum rate and energy efficiency (EE) are investigated for the massive multiple-input multiple-output (Massive MIMO) downlink with channel aging in the time varying Ricean fading channel. Specifically, the expression of the achievable sum rate of the system for the maximum ratio transmission (MRT) precoder with aged channel state information (CSI) in the time varying Ricean fading channel is first presented. Based on the expression, the effect of both channel aging and the Ricean factor on the power scaling law are studied. It is found that the transmit power of base station (BS) is scaled down by $1/{\sqrt{M}}$(where M is the number of the BS antennas) when the Ricean factor K is equal to zero (i.e., time varying Rayleigh fading channel), indicating that aged CSI does not affect the power scaling law. However, the transmit power of the BS is scaled down by 1/M for the time varying Ricean fading channel (where $K{\neq}0$) indicating that the Ricean factor affects the power scaling law and sum rate, and channel aging only leads to a reduction of the sum rate. Second, the EE of the system is analyzed based on the general power consumption model. Both the theoretical analysis and the simulations show that the channel aging could degrade the sum rate and the EE of the system, and it does not affect the power scaling law.