• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.965-966
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• 2006

As billion transistors system-on-chip (SoC) design becomes a reality, the productivity gap between rapidly increasing design complexity and designer productivity lagging behind is becoming a more serious problem to be solved. To reduce the gap, we present a system that generates executable transaction level models automatically. It speed up the SoC design space exploration process at various abstraction levels.

• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.315-327
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• 2007

Mathematical aspects of the electromagnetic surface-wave propagation are examined for the dielectric core consisting of multiple sub-layers, which are embedded in the gap between the two bounding cladding metals. For this purpose, the linear problem with a partial differential wave equation is formulated into a nonlinear eigenvalue problem. The resulting eigenvalue is found to exist only for a certain combination of the material densities and the number of the multiple sub-layers. The implications of several limiting cases are discussed in terms of electromagnetic characteristics.

• 플랜트 저널
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• 제7권2호
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• pp.30-38
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• 2011

The purpose of this paper is to review the understanding of pollution causes in the excitation system and how to solve the problem. The cause of the problem was in-leakage of bearing lubricant oil through the gap between rotor and outer in the air deflector, which was triggered by a negative pressure with respect to the operation of a collector ring fan in the collector house. In order to prevent exciting current transmission equipment pollutant, the reduction of the negative gage pressure of the inside of collector house is required. The protection in-leakage of bearing lubricant oil through the gap between rotor and outer of the air deflector are necessary. The reduction of the inside diameter of air deflector and the expansion of inlet filter of collector house are inevitable.

• Current Optics and Photonics
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• 제1권6호
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• pp.626-630
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• 2017

GaN-based green light-emitting diode (LED) structures suffer from low internal quantum efficiency (IQE), known as the "green gap" problem. The IQE of LED structures is expected to be improved to some extent by exploiting the Purcell effect. In this study, the Purcell effect on the IQE of green LED structures is investigated numerically using a finite-difference time-domain simulation. The Purcell factor of flip-chip LED structures is found to be more than three times as high as that of epi-up LED structures, which is attributed to the high-reflectance mirror near the active region in the flip-chip LED structures. When the unmodified IQE is 20%, the relative enhancement of IQE can be greater than 50%, without utilizing the surface-plasmon coupling effect. Based on the simulation results, the "green gap" problem of GaN-based green LEDs is expected to be mitigated significantly by optimizing flip-chip LED structures to maximize the Purcell effect.

• Communications for Statistical Applications and Methods
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• 제25권5호
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• pp.545-557
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• 2018

The inclusion of covariates in the model often affects not only the estimates of meaningful variables of interest but also its statistical significance. Such gap between statistical and subject-matter significance is a critical issue in huge sample studies. A popular huge sample study, the sample cohort data from Korean National Health Insurance Service, showed such gap of significance in the inference for the effect of obesity on cause of mortality, requiring careful consideration. In this regard, this paper proposes a sample size calibration method based on a Monte Carlo t (or z)-test approach without Monte Carlo simulation, and also proposes a test procedure for subject-matter significance using this calibration method in order to complement the deflated p-value in the huge sample size. Our calibration method shows no subject-matter significance of the obesity paradox regardless of race, sex, and age groups, unlike traditional statistical suggestions based on p-values.

• 설비공학논문집
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• 제6권2호
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• pp.67-77
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• 1994

In this study, one-dimensional Stefan problem with air-gap resistance in the rectangular mold is considered and the thermal characteristics are examined by using the enthalpy-based simple implicit finite-difference scheme. The enthalpy and temperature are nondimensionalized to obtain general solutions. The temperature distribution and the locations of solidus and liquidus line are obtained and the effects of major parameters on the thermal characteristics are investigated.

• 대한가정학회지
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• 제38권10호
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• pp.97-115
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• 2000

This study stems from the speculation that consumer life will be limited if consumers are not involved in the cyberspace and focuses on the differences of consumer competence as a result of information gaps among consumers. A cluster analysis is applied for cortege students who are ahead of the rest of the society in terms of the information level. Over the half of the students is grouped as a general level of information, about one quarter of those as an advanced level, and about one tenth as a behind level. The levels of consumer competence are very much differed among the three groups of students. This result indicates that information gap will be another source of consumer problem in an information society. Therefore, much more attention should be focused on the information gaps among consumers.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.753-757
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• 2003

외래 단백질 생산을 위한 숙주로는 Escherichia coli 및 Saccharomyces cerevisiae를 포함한 효모 균주들이 이용되어져 왔다. S. cerevisiae는 대장균에 비해 단백질의 접힘과 분비 능력이 우수하며, 안전한 균주(GRAS)로 알려져 있다. 그러나 S. cerevisiae의 단점은 대장균의 외래 단백질 발현양의 20% 이하 수준의 낮은 외래 단백질 발현율에 있다. 본 연구에서는 S. cerevisiae에서 외래 단백질의 발현을 향상시키기 위해 GAP promoter를 대상으로 분자진화를 수행하였으며, 이 결과 발현율이 360% 증가된 GAP promoter 변이체를 획득하였다.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.315-325
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• 2018

This paper investigates optimum air-gap flux distribution with third harmonic rotor flux orientation adjustment for five-phase induction motor. The technique of objective is to generate a nearly rectangular air-gap flux, and it improves iron utilization under variation loading conditions. The proportional relations between third harmonic and fundamental plane currents is usually adopted in the conventional method. However, misalignment between fundamental and third harmonic component occurs with variation loading. The iron of stator teeth is saturated due to this misalignment. This problem is solved by third harmonic rotor flux orientation adjustment simultaneously, and direction and amplitude are changed with mechanical load variation. The proposed method ensures that the air-gap flux density is near rectangular for a maximum value from no load to rated load. It is confirmed that the proposed method guarantees complete both planes decoupling with third harmonic flux orientation adjustment. The effectiveness of the proposed technique is validated experimentally.

• Journal of Welding and Joining
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• 제16권1호
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• pp.52-62
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• 1998

Laser beam welding of zinc-coated steel, especially lap joints, has a problem of zinc vapor produced during welding which has a low vaporization temperature of 906.deg. C. It is lower than the melting temperature of steel (1500.deg. C). The high pressure formed by vaporization of zinc during laser welding splatters the molten pool and creates porosities in weld. During laser lap welds of zinc-coated steel sheets with CW CO$_{2}$ laser the gap size has been analyzed and simulated using a FEM. The simulation has been carried out in the range of gap aetween 0 and 0.16 mm. The vaporized zinc gas has effected to prevent heat from conducting toward the bottom of sheets. In vaporized zinc gas has effected to prevent heat from conducting toward the bottom of sheets. In the case of too small gap size, zinc gas has not ejected and existed between two sheets. Therefore heat was difficult to conduct from the upper sheet to lower sheet and the upper sheet could over-melted. In the case of large gap size the zinc gas has been prefectly ejected but only a part of lower sheet has melted. The optimum range of gap size in the lap welds of zinc-coated steel sheets has been calculated to be between 0.08 and 0.12 mm. According to the comparison of experiment, the simulation is proved to be acceptable and applicable to laser lap welds.