• 한국화재소방학회논문지
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• 제18권1호
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• pp.42-48
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• 2004

다중이용시설의 화재 시 온도분포 및 연기유동 모델링은 결정론적 모델(Deterministic Model)인 존모델 (Zone Model)과 필드모델(Field Model)이 주로 사용되고 있다. 존모델은 공간을 두개의 지역으로 구분하여 화재현상을 분석하고, 필드모델은 공간을 다수의 Cell로 구분하여 분석하고 있으나 두 모델의 비교치에 대해서는 효용성 검증에 어려움을 겪고 있다. 따라서 화재현상의 모델링에 따른 수치적 이해와 관련자료의 검증을 통하여 실 상황에 보다 근접한 새로운 모델의 개발이 요구된다. 본 논문에서는 두 모델을 복합상영관의 실내공간에 적용하여 그 효용성을 분석해본 결과 공간 평균분포도에서는 존모델이, 세부적 공간현상에서는 필드모델의 적용이 적절한 것으로 판단된다. 또한 구체적인 화재의 성상과 감지기의 위치선정, 연기제어를 위한 제연설비의 검토를 위해서는 필드모델의 활용이 더욱 효과적이다.

• Korean Journal of Mathematics
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• 제4권2호
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• pp.141-148
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• 1996

• Smart Structures and Systems
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• 제16권6호
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• pp.1091-1105
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• 2015

Piezoelectric coefficient and dielectric constant of PZT-5H vary with electric field. In this work, variations of these coefficients with electric field are included in finite element modelling of a cantilevered plate instrumented with piezoelectric patches. Finite element model is reduced using modal truncation and then converted into state-space. First three modal displacements and velocities are estimated using Kalman observer. Negative first modal velocity feedback is used to control the vibrations of the smart plate. Three cases are considered v.i.z case 1: in which variation of piezoelectric coefficient and dielectric constant with electric field is not considered in finite element model and not considered in Kalman observer, case 2: in which variation of piezoelectric coefficient and dielectric constant with electric field is considered in finite element model and not considered in Kalman observer and case 3: in which variation of piezoelectric coefficient and dielectric constant with electric field is considered in finite element model as well as in Kalman observer. Simulation results show that appreciable amount of change would appear if variation of piezoelectric coefficient and dielectric constant with r.m.s. value of electric field is considered.

• Journal of Mechanical Science and Technology
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• 제15권9호
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• pp.1319-1327
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• 2001

The results of stand and field testing of a combustion chamber for a heavy-duty 150 MW gas turbine are discussed. The model represented one of 14 identical segments of a tubular multican combustor constructed 1:1 scale. The model experiments were executed at a lower pressure than that in a real gas turbine. Combustion efficiency, pressure loss factor, pattern factor, liner wall temperature, flame radiation, fluctuating pressure and NOx emission were measured at partial and full loads for both model and on-site testing. The comparison of these items in the stand and field test results led to has the development of a method of calculation and the improvement of gas turbine combustors.

• East Asian mathematical journal
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• 제32권3호
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• pp.387-397
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• 2016

This paper is concerned with the optimal control problem for some reaction diusion model. That is, we show the existence of the global weak solution for the Field-Noyes model. We also show the existence of the optimal control.

• Journal of Biosystems Engineering
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• 제29권1호
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• pp.1-8
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• 2004

In order to solve the shortage of roughage supply for dairy farm in Korea, winter cereal forage production after harvesting of rice in the fallow paddy field was studied. Two parts are already reported at the previous paper - One was the model development of the mechanized production, and the other was the study of feasibility of the model and its desirable direction in Korea. In this study, the model system is applied for a winter cereal wrap silage production model to practice in Kyungbook National University farm on 3ha scale for 3 years. Results of the research are summarized as follows; It takes 2 or 3 working days to process the wrap silage in middle of May in Daegu region. Also, not much particular problem can be found during the application test of mechanized wrap silage production. Field capacity and field efficiency are estimated to be 0.6-0.85㏊/h and 50-70% in mowing, 1.1∼1.7㏊/h and 52∼80% in tedding and raking, 0.6∼1.1㏊/h and 25∼45％ in baling and 0.5∼0.57㏊/h and 75∼85% in wraping, respectively. Total production cost is estimated to be 1,257won/kg-TDN in oversowing and wrap-silage harvest in 1.6㏊ working area. As a result, large scale field is recommended to produce the wrap silage in order to maximize the field capacity.

• Journal of Astronomy and Space Sciences
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• 제28권1호
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• pp.27-36
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• 2011

The present study examines the morning-afternoon asymmetry of the geosynchronous magnetic field strength on the dayside (magnetic local time [MLT] = 06:00~18:00) using observations by the Geostationary Operational Environmental Satellites (GOES) over a period of 9 years from February 1998 to January 2007. During geomagnetically quiet time (Kp < 3), we observed that a peak of the magnetic field strength is skewed toward the earlier local times (11:07~11:37 MLT) with respect to local noon and that the geosynchronous field strength is larger in the morning sector than in the afternoon sector. That is, there is the morning-afternoon asymmetry of the geosynchronous magnetic field strength. Using solar wind data, it is confirmed that the morning-afternoon asymmetry is not associated with the aberration effect due to the orbital motion of the Earth about the Sun. We found that the peak location of the magnetic field strength is shifted toward the earlier local times as the ratio of the magnetic field strength at MLT = 18 (B-dusk) to the magnetic field strength at MLT = 06 (B-dawn) is decreasing. It is also found that the dawn-dusk magnetic field median ratio, B-dusk/B-dawn, is decreasing as the solar wind dynamic pressure is increasing. The morning-afternoon asymmetry of the magnetic field strength appears in Tsyganenko geomagnetic field model (TS-04 model) when the partial ring current is included in TS-04 model. Unlike our observations, however, TS-04 model shows that the peak location of the magnetic field strength is shifted toward local noon as the solar wind dynamic pressure grows in magnitude. This may be due to that the symmetric magnetic field associated with the magnetopause current, strongly affected by the solar wind dynamic pressure, increases. However, the partial ring current is not affected as much as the magnetopause current by the solar wind dynamic pressure in TS-04 model. Thus, our observations suggest that the contribution of the partial ring current at geosynchronous orbit is much larger than that expected from TS-04 model as the solar wind dynamic pressure increases.

• 수산해양교육연구
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• 제25권4호
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• pp.937-957
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• 2013

This study was conducted for the purpose of developing the UCC project teaching and learning model based on the rationale which are applicable effectively in the field of university education. Firstly, we have designed the rationale based on the research of documents and preceding researches about teaching method models. Secondly, we have developed the UCC project teaching and learning model. the UCC project teaching and learning model based on the rationale was assessed by the professional formative evaluation group and tested in the field of university education in advance and thereafter. It was finally rectified and supplemented. Particularly, any corrections were to be made repeatedly in the stage of developing of the UCC project. And also, during the assessment and arrangement process, it was designed for the study participants to feel a sense of achievement as learners who combine knowledge and attitudes toward participants'subjects of the curriculum and professional vocational skills by performing the nursing science training scene which could happen in the field. Thirdly, the final version of the UCC project teaching and learning model was verified in its effectiveness by being applied in the field of the nursing science education in the $2^{nd}$ step. As a result, we noticed that learners diverse abilities were improved through systemic process and performing elements such as teaching plan which was needed for designing the UCC project in the field, making storyboard and skills for making video contents. We hope that the UCC project teaching and learning model in this study will be used by the students for designing, developing and utilizing educational UCCs which are necessary in industrial fields and it will contribute for training university students as professionals having the practical skills in the field.

• 농업생명과학연구
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• 제44권5호
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• pp.101-107
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• 2010

The objective of this study was to assess the statistics and associated criteria for field-scale model used to simulate nutrient concentrations in paddy field. CREAMS-PADDY, a modified version of the field-scale CREAMS model, simulates the hydrologic, sediment, and nutrient cycles in paddy fields was applied in this study. The model was calibrated and validated using data from study rice paddy fields in Republic of Korea. The calibration statistics include mean and the minimum-maximum range associated with a "temporal window" that spans a period of several days. Because nutrient concentrations in paddy filed are typically sampled infrequently (on a weekly basis, at best) and represent only an instant in time, it is not reasonable to expect any model to simulate a daily average concentration equal to an observed value on a particular day. The 5-day window and related calibration statistics were applied in this study and the applicability of this concept was tested for field-scale water quality model. As a result of calibration and validation, the ponded water nutrient concentration values showed only small changes except the fertilization period. Because of the small changes in ponded water concentration, the size of 5-day window was too small to capture the observed values. Further study is required to establish the 5-day window calibration method for field-scale water quality modeling.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.67-70
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• 1991

When analyzing field or optimizing the shape of electrode in three dimensional space by using the surface charge method, we need to divide finely the surface of electrode into surface element like triangle or rectangle. In this case, there exist any variables in field analysis or field optimization. In particular, smoothness on the surface of optimized shape is not good. Recently, A paper is published where introducing NURB curve to field analysis and field optimization about two dimensional space model and axial symmetric three dimensional space model results in reduced variables, enhenced accuracy and improved smoothness. NURB curve has some useful properties like continuity, controllability and locality. Therefore in this paper, in order to improve the demerits of the established optimization method for three dimensional space models, the NURB surface that has same properties in common with NURB curve is used to analyze and optimize simple model.