• 한국컴퓨터정보학회논문지
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• 제13권4호
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• pp.1-9
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• 2008

대부분의 전자제품은 날로 다양한 소비자의 니즈로 인해 수많은 라인업을 보유하고 있다. 이에 대응하기 위해 보통 '베이스 모델'이라 불리는 초기 개발모델에서 각 상품화 과제의 특정 요구사항을 반영하여 파생개발을 한다. 제품 라인업에 기반한 소프트웨어 라인 업이 형성되는 개발환경에서 '베이스 코드'의 구조와 그 구성요소의 품질은 향후 파생되는 여러 많은 제품의 생산성과 품질의 근간이 된다. '베이스코드'는 최초 개발 후 여러 상품화를 거치면서 그 구조와 코드 자체에 수많은 변경이 가해진다. 상품화 과제의 요구사양에 따라 변경되거나 추가되는 기능의 구현은 필수적 활동이며, 성능 개선 및 문제점 해결을 위한 구조 및 코드의 변경 역시 상품화를 통해 지속적으로 발생하는 유지관리 활동이다. 하지만 위와 같은 변경은 최초 설계 시 의도된 구조가 깨지거나 코드의 복잡도가 증가하는 등의 노쇠화 징후(Ageing symptom)로 나타나 유지관리에 어려움을 준다. 본 논문은 노쇠화 된 베이스 코드의 상품화 적용 효율을 높이기 위해 재사용성, 유지보수성, 확장성 등의 비기능적 요소(quality attribute)의 개선을 위한 절차와 기법으로 리엔지니어링 프레임워크를 제안한다.

• 대한화장품학회지
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• 제46권4호
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• pp.391-401
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• 2020

플라보노이드(flavonoid)는 식물 등의 대사체에서 유래한 폴리페놀 계열의 화합물이며, 다양한 인체생리작용을 조절할 수 있는 것으로 알려져 있다. 이중 3,3',3',7-tetrahydroxyflavone (fisetin)은 다양한 과일과 채소에서 발견되며, 최근 노쇠용해(senolytic) 활성을 통해 특정 조직의 기능을 회복시킨다는 것이 알려졌다. 본 연구에서는 인간 표피 각질세포를 대상으로 하여 fisetin의 피부장벽 유전자 발현 조절 및 항노화 효능을 분석하였다. Fisetin은 말단소립 역전사효소(telomerase)의 활성을 증가시켰으며, CDKN1B 유전자의 발현을 감소시켰다. 또한 피부장벽을 구성하는 주요 유전자인 KRT1, FLG, IVL, DSP의 발현을 증가시켰으며, 세라마이드 합성효소의 일종인 CerS3, CerS4 유전자의 발현을 증가시켰다. 이러한 결과는 fisetin의 효능이 노쇠용해에 국한되지 않고 인간 각질세포의 다양한 생리학적 조절에도 관여함을 보여준다. 따라서 fisetin은 화장품 및 의약품 등의 생리활성 조절물질로 활용될 수 있다고 사료된다.

• Journal of Plant Biology
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• 제31권3호
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• pp.227-237
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• 1988

Effects of putrescine on senescence in detached leaves of Chinese cabbage (Brassica campestris L.) in the light were investigated. The putrescine as a potent antisenescence substane markedly inhibited chlorophyll and protein loss at the 10mM concentraton in the detached leaves during the dark incubation. In the light, however, putrescine showed the opposite effects to dark incubation. The chlorphyll loss by putrescine in the light was stopped with darktransfer, and inhibited competitively by a divalent cation Ca2+. In the light, putrescine reduced the protease activity. Putrescine, in the light, increased H2O2 content and reduced the activities of enzymes -superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6-involved in inhibiting the accumulation of free radicals. These results suggest that the effects of puterscine on chlorophyll and protein loss in detached leaves of Chinese cabbage in the light are related to the cationic nature of putrescine and the accumulation of free radicals.

• 전자공학회논문지A
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• 제31A권1호
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• pp.54-60
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• 1994

In this paper, we present the analytical models for the change of the lateral electric field distribution and the velocity saturation region length with the electron trapping of stressed SC-PMOSFET in the saturation region. To derive the hot-electron-induced lateral electric field of stressed SC-PMOSFET. Ko's pseudo two dimensional box model in the saturation region which illustrates the analysis of the velocity saturation region is modified under the condition of electron trapping in the oxide near the drain region. From the results, we have the following lateral electric field in the y-direction, that is, E(y) ES1satT.cosh(y/l) qNS1tT.sinh(y/l)/lCox. It is shown that the trapped electrons influence the field in the drain region. decreasing the lateral electric field. Calculated velocity saturaion length increases with the trapped electrons. increasing the drain current of stressed SCPMOSFET. This results well explain the HEIP phenomenon of PMOSFET's.

• 월간당뇨
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• 통권209호
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• pp.19-24
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• 2007

당뇨병에 성기능장애가 많다는 것은 옛날부터 알려져 있지만 실제로는 그릇된 지식과 선입관에 의해 과장되게 잘못알고 있는 경우가 많다. 당뇨병이라고 모두 발기부전 환자는 아닌 것이며 정상 건강인보다 조금 높은 빈도를 보이는 것뿐이다. 식사요법과 운동요법으로 혈당조절을 잘하고 합병증을 예방하면 정상인과 다름없는 성생활을 할 수 있으며 인슐린 치료를 계속하면서 주의 깊게 혈당을 조절하고 합병증을 예방하면 60세 이후까지도 정상적인 성생활이 가능하다. 정상인도 노쇠하면 자연현상으로 언젠가는 모두 발기부전이 되므로 당뇨병환자만이 발기부전이 오는 것은 아니므로 미리 겁내고 불안해할 필요는 없는 것이다. 당뇨병환자중에는 선입관에 의해 당뇨라는 진단을 받고 정신적 충격과 그릇된 지식으로 심인성 발기부전에 빠지는 사람이 상당히 많다. 그러므로 당뇨병환자는 정상인보다 더 많은 노력을 하며 합병증의 병발을 미연에 방지하는 것이 가장 중요하다.

• 대한전자공학회논문지
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• 제25권7호
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• pp.780-790
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• 1988

We have studied the hot-carrier-induced degradation caused by the high channel electric field due to the decrease of the gate length of MOSFET used in VLSI. Under DC stress, the condition in which maximum substrate current occures gave the worst degradation. Under AC dynamic stress, other conditions, the pulse shape and the falling rate, gave enormous effects on the degradation phenomena, especially at 77K. Threshold voltage, transconductance, channel conductance and gate current were measured and compared under various stress conditions. The threshold voltage was almost completely recovered by hot-injection stress as a reverse-stress. But, the transconductance was rapidly degraded under hot-hole injection and recovered by sequential hot-electron stress. The Si-SiO2 interface state density was analyzed by a charge pumping technique and the charge pumping current showed the same trend as the threshold voltage shift in degradation process.

• 전자공학회논문지A
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• 제30A권9호
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• pp.38-45
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• 1993

In this study, the degradation characteristics of drain output resis-tance was described due to hot electron effects. An semi-empirical model for the degraded drain output resistance was derived from the measured device characteristics. The suggested model was verified from the measured data and the device parameter dependence was also analyzed. The degradation of drain output resistance was increased with stress time and had linear relationship with the degradation of drain current. The device lifetime which was defined by failure criteria of drain output resistance (such as $\Delta$ro/roo=5%) was equivalent to that of failure criteria of drain current (such as $\Delta$ID/ID=5%)

• Journal of Plant Biology
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• 제31권2호
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• pp.155-164
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• 1988

The rapid senescence of detached Chinese cabbage leaf discs in darkness is first manifested by a sharp rise in malondialdehyde content (indicated by distruption of membrane structure), then by a rise in peroxidase activity and a decrease in catalase activity, and ultimately by chlorophyll degradation. These changes in parameters besides the catalase activity during senescence were delayed by application of spermidine. Especially, 10-4M spermidine almost completely arrested chlorophyll degradation after incubaton over 5 days. Spermidine reduced the amount of ethylene produced by senescing leaf discs. Additionally, it also reduced IAA-induced ethylene production. Calcium ion (1mM, 10mM) supplied together with the spermidine diminished the spermidine action, indicating probable involvement of an initial ionic attachment mechanism. These results suggest that spermidine can be used as an anti-senescence agent for plants and that this agent may stabilize membrane structure through interaction with the negatively charged loci on the membrane and exert the influence during senescence.

• 전자공학회논문지A
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• 제33A권4호
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• pp.129-135
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• 1996

In this paper, the hot carrier effect and device degradation of deep submicrometer SC-PMOSFETs have been measured and characterized. It has been shown that the substrate current of a 0.15$\mu$m PMOSFET increases with increasing of impact ionization rate, and the impact ionization rate is a function of the gate length and gate bias voltage. Correlation between gate current and substrate current is investigated within the general framework of the lucky-electron. It is found that the impact ionization rate increases, but the device degradation is not serious with decreasing effective channel length. SCIHE is suggested as the possible phusical mechanism for enhanced impact ionization rate and gate current reduction. Considering the hot carrier induced device degradation, it has been found that the maximum supply voltage is about -2.6V for 0.15$\mu$m PMOSFET.

• 전자공학회논문지A
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• 제31A권8호
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• pp.72-79
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• 1994

In this paper semi empirical models are presented for the hot electron induced threshold voltage shift(${\Delta}V_{t}$) and effective channel shortening length (${\Delta}L_{H}$) in degraded PMOSFET. Trapped electron charges in gate oxide are calculated from the well known gate current model and ΔLS1HT is calculated by using trapped electron charges. (${\Delta}L_{H}$) is a function of gate stress voltage such as threshold voltage shift and degradation of drain current. From the correlation between (${\Delta}L_{H}$) has a logarithmic function of stress time. From the measured results, (${\Delta}V_{t}$) and (${\Delta}L_{H}$) are function of initial gate current and device channel length.