• 대한기계학회논문집A
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• 제31권1호
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• pp.89-96
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• 2007

A volume integral equation method (VIEM) is applied for the effective analysis of plane elastostatic problems in unbounded solids containing single isotropic inclusion of two different shapes considering composite fiber volume fraction. Single cylindrical inclusion and single square cylindrical inclusion are considered in the composites with six different fiber volume fractions (0.25, 0.30, 0.35, 0.40, 0.45, 0.50). Using the rule of mixtures, the effective material properties are calculated according to the corresponding composite fiber volume fraction. The analysis of plane elastostatic problems in the unbounded effective material containing single fiber that covers an area corresponding to the composite fiber volume fraction in the bounded matrix material are carried out. Thus, single fiber, matrix material with a finite region, and the unbounded effective material are used in the VIEM models for the plane elastostatic analysis. A detailed analysis of stress field at the interface between the matrix and the inclusion is carried out for single cylindrical or square cylindrical inclusion. Next, the stress field is compared to that at the interface between the matrix and the single inclusion in unbounded isotropic matrix with single isotropic cylindrical or square cylindrical inclusion. This new method can also be applied to general two-dimensional elastodynamic and elastostatic problems with arbitrary shapes and number of inclusions. Through the analysis of plane elastostatic problems, it will be established that this new method is very accurate and effective for solving plane elastic problems in unbounded solids containing inclusions considering composite fiber volume fraction.

• 간호행정학회지
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• 제19권4호
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• pp.536-543
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• 2013

Purpose: The purpose of this study was to identify the mediating effect of professionalism in the relationship between clinical competence and field adaptation in newly graduated nurses. Methods: The participants in this study were 213 nurses from four tertiary hospitals who had less than 12 months of nursing experience. Data were collected during January and February, 2013. A structured questionnaire was used for data collection and data were analyzed using descriptive statistics, Pearson correlation coefficients, and path analysis with the SPSS/WIN 21.0 and AMOS 21.0 programs. Results: The mean score for clinical competence was $2.85{\pm}0.25$, for professionalism, $3.10{\pm}0.30$, and for field adaptation, $2.79{\pm}0.37$. There was a significant positive relationship between clinical competence and field adaptation. Also, professionalism was positively correlated with field adaptation. Professionalism showed mediating effects between clinical competence and field adaptation. Improvement of clinical competence increased professionalism and the increased professionalism raised the field adaptation. Conclusion: Based on these findings, orientation programs including strategies to increase professionalism, should be established to promote effective field adaptation in newly graduated nurses. These orientation programs can strengthen professionalism, the mediator between clinical competence and field adaptation in newly graduated nurses.

• Journal of Biosystems Engineering
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• 제24권2호
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• pp.135-144
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• 1999

An yield monitoring system plays a key role in precision farming. An yield monitoring system and a DGPS were implemented to a widely used domestic combine for yield mapping of a small sized paddy field, and yield mapping algorithms were investigated in this study. The yield variation in the 0.1ha rice paddy field was measured by installing a yield flow sensor and a grain moisture sensor at the end of the clean grain elevator discharging grains into a grain tank. Yield map of the test filed was drawn in a point map and a linear interpolated map based on the result of the field test. The size of a unit yield grid in yield mapping was determined based on the combine traveling speed, effective harvesting width and data storing period. It was possible to construct the yield map of a small sized paddy field.

• 한국군사과학기술학회지
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• 제6권4호
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• pp.147-158
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• 2003

The prediction of wind field is very important fact in the radioactive and chemical warfare. In spite of advanced numerical weather prediction modelling and computing technology, the high resolution prediction of wind field is limited by the very high integration costs. In this study we coupled the mesoscale numerical model and microscale diagnostic numerical model with minimized integration costs. This coupled model has not only the ability of prediction of high resolution wind field including complex building but also microscale pollutant diffusion fields. For military operation this system can help making a practical and cost-effective decision in a battle field.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권9호
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• pp.407-411
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• 2003

The purpose of this paper is to study the removal of nitrogen oxide(NOx) using a wire-plate type plasma reactor with magnet attached for indoor air purification. In order to produce a more effective reactor, we conducted magnetic field simulations. The results of the magnetic field simulations show that NOx can be removed more effectively. The results from the magnetic field simulation show that when 7 magnets were applied to the reactor, the magnetic flux density was at its highest amount than when using 0, 3, or 5 magnets. From the data obtained by the simulation results a plasma reactor was made and thus, several experiments were conducted. The best removal efficiency was obtained with 14 W AC power to the reactor with 5 magnets.

• 전자공학회논문지A
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• 제31A권4호
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• pp.77-83
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• 1994

In this paper we numerically approximated the field-effect mobility of a-Si:H TFT. Field-effect mobility, based on the charge-trapping model and new effective capacitance model in our study, used Chebyshev approximation was approximated as the function of gate potential(gate-to-channel voltage). Even though various external factors are changed, this formula can be applied by choosing the characteristic coefficients without any change of the approximation formula corresponding to each operation region. Using new approximated field-effect mobility formula, the dependences of field-effect mobility on materials and thickness of gate insulator, thickness of a-Si bulk, and operation temperature in inverted staggered-electrode a-Si:H TFT were estimated. By this was the usefulness of new approximated mobility formula proved.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.232-233
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• 2010

This paper investigates occupational exposure to time-varying magnetic field generation in high power rectifier systems. Two different kinds of high power rectifier systems of 25kA are modeled and analyzed. The performance is compared and evaluated on the basis of exposure guidelines from ICNIRP. In order to focus on the qualitative effect of rectifier operation, the mechanical structure of current carrying conductors is simplified as infinite long bus-bar model and low frequency harmonic contents up to 65kHz are considered. Thyristor rectifier generates a significant amount of low frequency magnetic field harmonic contents both at ac and dc side of rectifier infringing the limit from ICNIRP. The multilevel rectifier-IGCT type has almost negligible field generation from ac input side and smaller harmonic contents in dc load side complying with ICNIRP guideline. This remarkable advantage of multilevel rectifier-IGCT type can lead to very simple site layout design for installation and cost-effective compliance to guideline of occupational exposure against magnetic field.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.658-664
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• 2015

Lens designers generally refer to flat image fields and attempt to minimize the field curvature. Present-day CMOS image sensors for mobile phone cameras, however, are not flat, but curved. Sometimes it is necessary to generate an intentional field curvature according to the degree and direction of the CMOS image-sensor’s curvature. This paper presents the degree of curvature of a CMOS image sensor measured using an interferometer, and proposes an effective compensation method that minimizes the net field curvature through optimizing the air gap between lens elements, which is demonstrated using simulations and experiments.

• 한국재료학회지
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• 제16권7호
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• pp.408-411
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• 2006

An effective wet-chemical approach is demonstrated for growing large-area, selectively-patterned, and low-temperature-synthesized ZnO nanorods (ZNRs). The growth of ZNRs was enhanced on a Co layer. The selectivity and density were readily controlled by the control of the temperature when the substrate transfers into aqueous solution. The cross-sectional transmission electron microscopy image shows that single crystalline ZNRs grown along [0001] have good adhesion at interface between ZNRs/substrate. The turn-on field was 4 $V/{\mu}m$ at the emission current density of 1 ${\mu}A/cm^2$. The stable emission was obtained at 0.11 $mA/cm^2$ under 7.2 $V/{\mu}m$ over 10 hr. These results suggest that selectively-patterned ZNRs have the potential for use as field emitters in large-area field emission displays.

• 전자공학회논문지SC
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• 제47권1호
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• pp.42-46
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• 2010

정보보안을 위한 암호화는 종종 Galois Field 상에서 산술 연산의 형태로 이루어진다. 본 논문은 Galois Field 상에서 산술 정보의 지수 연산 처리를 효과적으로 수행하는 방법을 제안한다. 특히 기존의 비트별 병렬 처리 지수 연산기에서 게이트 카운트가 큰 요소를 제거하고, 시스템 상수를 효과적으로 사용하도록 개량함으로써, m 값이 큰 경우에도 고성능인 VLSI 시스템을 설계한다.