• JSTS:Journal of Semiconductor Technology and Science
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• 제12권1호
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• pp.75-87
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• 2012

A design paradigm using sequential geometric programming is presented to accurately design CMOS op amps with BSIM3. It is based on new adaptive modeling of transistor parameters through the operating point simulation. This has low modeling cost as well as great simplicity and high accuracy. The short-channel dc, high-frequency small-signal, and short-channel noise models are used to characterize the physical behavior of submicron devices. For low-power and low-voltage design, this paradigm is extended to op amps operating in the subthreshold region. Since the biasing and modeling errors are less than 0.25%, the characteristics of the op amps well match simulation results. In addition, small dependency of design results on initial values indicates that a designed op amp may be close to the global optimum. Finally, the design paradigm is illustrated by optimizing CMOS op amps with accurate transfer function.

• 한국전기전자재료학회논문지
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• 제25권9호
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• pp.677-680
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• 2012

The dependency of annealing temperature on the electrical performances in amorphous silicon-zinc-tin-oxide thin film transistors (SZTO-TFT) has been investigated. The SZTO channel layers were prepared by using radio frequency (RF) magnetron sputtering method with different annealing treatment. The field effect mobility (${\mu}_{FE}$) increased and threshold voltage ($V_{th}$) shifted to negative direction with increasing annealing temperature. As a result, oxygen vacancies generated in SZTO channel layer with increasing annealing temperature resulted in negative shift in $V_{th}$ and increase in on-current.

• 수면정신생리
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• 제10권1호
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• pp.20-25
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• 2003

Many people suffer from chronic insomnia. Inappropriate sleep causes attention difficulties, decreased work efficiency, and increased traffic accidents and disasters. Evaluating the precise causes of insomnia prior to treatment is very important, because chronic insomnia can be a secondary symptom of other medical, psychiatric, and sleep disorders. Medication and behavior therapy are not exclusive of each other, and both treatments are beneficial to some patients, but currently many physicians and patients tend to be dependent only on medication. While long-term medication causes various degrees of dependency, tolerance, and withdrawal symptoms, behavior therapy has a stable effect over a long period. Behavior therapy is one of the most important treatment modalities for chronic insomnia. It shortens sleep latency, and decreases frequency of awakening during sleep. The rationale and practice of currently used behavior therapy and light therapy will be reviewed in this study.

• 전자공학회논문지D
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• 제36D권4호
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• pp.42-47
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• 1999

통상의 마이크로웨이브 대역의 여파기는 전기적 길이의 주파수 의존성을 이용한 1/2파장 또는 1/4파장의 공진기를 널리 사용한다. 그러나 차단 주파수가 존재하는 도파관은 특성임피던스도 주파수에 의존적이므로 이를 이용한 공진기의 구현이 가능하다. 이를 이용하여 1/4파장 보다 짧은 도파관의 공진기 등기회로를 추출하였고 상응하는 대역통과 여파기 설계법을 제시하였다. 이를 검증하기 위하여, 이 공진기와 집중소자 및 도파관 인버터를 이용한 대역통과 여파기를 각각 시뮬레이션하고, 후자에 대해서는 여러 가지 유전체로 채워진 도파관 4단 대역통과 여파기의 형태로 제작하였다. 본 논문의 여파기는 임의의 길이를 갖는 도파관을 공진부로 사용할 수 있다는 장점이 있다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.147-154
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• 2002

Dynamic response analysis are conducted for a floating bridge subjected to multiple support earthquake excitation. The floating bridge used in this study is supported by discrete floating pontoons and horizontal pretension cables supported at both ends of the bridge. The bridge is modeled with finite elements and the hydrodynamic added mass and added damping due to the surrounding fluid around pontoons are obtained using boundary elements. Multiple support excitation is introduced at both ends of the bridge and the time history response is compared to that of a simultaneous excitation. The results shows that the differences between two results are not so large except for cable tension for which the multiple support excitation yields larger values. During the analysis the concept of retardation function is utilized to consider the frequency dependency of the hydrodynamic coefficients.

• 한국시스템다이내믹스연구
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• 제15권4호
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• pp.85-100
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• 2014

We propose a composite make or buy decision model considering both the transaction cost theory and the resource based view in the Korean defense industry using System Dynamics. We analyze relationship between core variables(transaction frequency, technological uncertainty, the level of technological dependency, technological level and acquisition ability for market information) and 'Make or Buy decision' focused on technological innovation capability. Based on the result, we propose the implications as follows : First, the defence industry needs more R&D investment. Second, it needs a balance between domestic(Make) and overseas(Buy) to increase the technological capability rapidly.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1851-1856
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• 2008

A numerical program based on computational fluid dynamics has been developed to simulate characteristics of an EHD induction micropump. The ambiguity of boundary conditions was removed by adopting an equation formulated for electric potential as the dependent variable. The calculations show that the dependency of frequency agrees well with the experiments and the previous analysis. The instability, caused by backflows, is getting stronger as the channel depth increases, which is consistent with experiments. The present study reveals that it is due to the limit in the penetration depth which the electric field can affect. Despite the disadvantage of large channel depth, there is a certain optimal depth for the maximum flow rate.

• 복식문화연구
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• 제9권1호
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• pp.45-60
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• 2001

The purpose of this research is to offer basic data for the study of men's suit by investigating purchase behavior and fit of men's ready-made suit for Koran adult men. The subjects were male who aged 25∼39 and resided in Seoul, Kyunggi and Chungnam regions. The results of the research are summarized as the following : 1. Male consumers purchase suit most frequency at department, specially stores. As the consumers grow older dependency on their spouses'opinion for purchase decision increases. The standards of purchasing are stated to e design, price and color. 2. the male consumers are generally knowledgeable about the current sizing system. Yet, the knowledge is confused with the pst and present systems. 3. When the male consumers purchase, they consider mainly for the fit of th d\\body part are shoulders for the jacket and waist, hip for the pants. 4. The attitude to toward the combination of sizes for the jacket is comparatively satisfaction than pants. Specially, most negative part of jacket is the length of sleeve.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.202-205
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• 1996

In this paper it is researched a relation between network structures and electrical properties - especially dielectric characteristics with changing of network structure. It is resulted that the specimens which have single network structures have smaller dielectric loss than SIN specimens but have relatively larger dependency to variation of temperature and frequency. For that reason formation of structures is attained by introducing of SIN to insulating materials. therefore it is counted that introduction of multiple structure including SIN is necessary to improve heat proof and electrical properties.

• Preventive Nutrition and Food Science
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• 제2권1호
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• pp.6-10
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• 1997

The reaction mechanisms and kinetics of tertiary butylhydroquinone(TBHQ) as an antioxidant in soybean oil oxidation were studied. The oxidation reaction of soybean oil at 55, 60 and $65^{\circ}C$ was a first order. The activation energies of soybean oil containing 0, 25, 50, and 75ppm TBHQ were 12.15, 6.05, 6.15 and 6.17kcal/mole. respectively. The addition of THQ to soybean oil containing 0, 25, 50, and 75ppm TBHQ were 1.88$\times${TEX}$10^{7}${/TEX}, 4.10$\times${TEX}$10^{2}${/TEX}, 4.32 $\times${TEX}$10^{2}$p/TEX} and 3.97$\times${TEX}$10^{2}${/TEX}, respectively. The decrease of frequency factor rather than the activation energy. The effects of antioxidants on the temperature dependecy of lipid oxidation could be effectively evaluated by measuring their effects on the activation energy of lipid oxidation.