• 천문학논총
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• 제30권2호
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• pp.549-552
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• 2015

The galactic magnetic field (GMF) and the intergalactic magnetic field (IGMF) affect the propagation of ultra-high energy cosmic rays (UHECRs) from the source to us. Here we examine the influences of the GMF/IGFM and the dependence of their sky distribution on galactic latitude, b. We analyze the correlation between the arrival direction (AD) of UHECRs observed by the Pierre Auger Observatory and the large-scale structure of the universe in regions of sky divided by b. Specifically, we compare the AD distribution of observed UHECRs to that of mock UHECRs generated from a source model constructed with active galactic nuclei. Our source model has the smearing angle as a free parameter that reflects the deflection angle of UHECRs from the source. The results show that larger smearing angles are required for the observed distribution of UHECRs in lower galactic latitude regions. We obtain, for instance, a $1{\sigma}$ credible interval for smearing angle of $0^{\circ}{\leq}{\theta}_s{\leq}72^{\circ}$ at high galactic latitudes, $60^{\circ}$ < $\left|{b}\right|{\leq}90^{\circ}$, and of $75^{\circ}{\leq}{\theta}_s{\leq}180^{\circ}$, $-30^{\circ}{\leq}b{\leq}30^{\circ}$, at low galactic latitudes, respectively. The results show that the influence of the GMF is stronger than that of the IGMF. In addition, we can estimate the strength of GMFs by these values; if we assume that UHECRs would have heavier nuclei, the estimated strengths of GMF are consistent with the observational value of a few ${\mu}G$. More data from the future experiments may make UHECR astronomy possible.

• 한국농공학회논문집
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• 제60권5호
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• pp.41-54
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• 2018

A method to account a detention in a rice paddy field in hydrologic modeling was tested at plot and watershed scales. Hydrologic Simulation Program - Fortran (HSPF) and its one of surface runoff modeling method, i.e Surface-Ftable, were used to simulate a inundated condition in a rice paddy culture for a study plot and basins in Saemangeum watershed. Surface-Ftable in HSPF defines surface runoff ratio with respect to surface water depth in a pervious land segment, which can be implemented to the feature of water management in a rice paddy field. A Surface-Ftable for paddy fields in Saemangeum watershed was developed based on the study paddy field monitoring data from 2013 to 2014, and was applied to Jeonju-chun and Jeongeup-chun basins which comprise 12% and 22% of paddy fields in the basins, respectively. Four gaging stations were used to calibrate and validate the watershed models for the period of 2009 and 2013. Model performed 7.13% and 9.68% in PBIAS, and 0.94 and 0.90 in monthly NSE during model calibrations at Jeonju and Jeongeup stations, respectively, while the models were validated its applicability at Hyoja and Gongpyung stations. The comparison of results with and without considering detention effect of paddy fields confirmed the validity of the Surface-Ftable method in modeling watersheds containing rice paddy fields.

• 실천공학교육논문지
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• 제16권3_spc호
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• pp.309-325
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• 2024

이 연구의 목적은 LINC 3.0 기술혁신선도형 사업운영의 객관적 검증과 성과분석을 위한 자체평가지표를 개발하는 데 있다. 이러한 목적을 달성하기 위해 인력양성 분야와 기술개발 및 사업화 분야의 평가지표를 개발하고 그 타당성을 검증하였다. 이를 위해 평가관련 선행연구 및 유사사례를 조사하여 평가모델 및 체계를 구성하고 평가지표를 개발하였다. 개발한 평가지표 및 척도는 2회의 델파이조사를 통해 타당성을 확보하였다. 연구결과, LINC 3.0 자체평가지표는 인력양성 분야와 기술개발 및 사업화 분야로 구분, 총 66개의 평가지표를 개발하였다. 인력양성 분야는 평가항목 13개, 평가지표 38개로 개발하였고, 기술개발 및 사업화 분야는 평가항목 12개, 평가지표 28개를 도출하였다. 본 연구는 LINC 3.0 사업의 자체평가지표를 개발함으로써 대학 산학협력 모델의 객관적 검증과 타당성을 높이는 방안을 제시하였다는 의의를 갖는다. 연구에서 개발한 평가지표에 대해서는 현장활용성을 토대로 지속적으로 고도화 작업이 필요하며, 평가결과 도출된 우수사례의 공유·확산을 통해 대학교육의 질적 수준을 높이고 경쟁력을 강화하는 것이 필요하다.

• 한국산학기술학회논문지
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• 제17권3호
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• pp.171-176
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• 2016

본 논문은 도로안전시설물의 공용중 부식 발생으로 인한 기능 손실을 줄일 수 있는 방안으로 고내식성 용융합금도금 강판을 적용한 도로안전시설물을 제안한다. 고내식성 용융합금도금강판을 적용한 도로안전시설물 제품에 대한 신뢰성 있는 충돌성능 평가 기초자료를 제공할 목적으로 고내식강이 적용된 교량난간 제품에 대한 충돌 시뮬레이션 및 실물 차량 충돌시험 연구를 수행한다. 시뮬레이션 및 실차충돌 시험 결과, 변형률 속도 의존성을 고려할 수 있는 정교한 동특성 재료모델을 도입한 충돌 시뮬레이션을 통해 얻어지는 충돌 거동과 실물 차량 충돌 시험 결과가 매우 유사한 것으로 도출되었다. 본 논문에서 제안된 고내식성 용융합금도금 강판을 적용한 교량난간은 실물 차량 충돌 시험의 충돌성능 평가 기준을 모두 충족시켜 현장 적용을 앞두고 있다.

• 한국시뮬레이션학회논문지
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• 제22권2호
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• pp.63-71
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• 2013

미래의 무기체계 개발은 점점 복잡해지고, 많은 비용이 소요된다. 무기체계 개발을 위해 M&S(Modeling & simulation)기술을 사용하는 것에 대한 관심이 점점 높아지고 있다. M&S기술은 훈련, 전략 수립, 교전수칙, 무기체계 획득 등을 하는데 활용된다. 본 논문에서는 교전급 모델의 운용을 위해 소규모 교전 시나리오 생성 방안을 제시 한다. 생성된 시나리오는 지휘관의 훈련, 체계 운용 분석, 전술 검증을 위해 사용된다. 이 연구에서는 FSA(Finite State Automata)이론과 DFS(Depth First Search)알고리즘을 이용해 시나리오를 생성하는 방법론을 제시하였다. 그리고 제안된 방법론을 이용해 공격함과 정찰함이 교전하는 소규모 교전 시나리오 예제에 적용하였으며 이를 Delta3D$^{TM}$로 가시화 하였다.

• 한국과학교육학회지
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• 제4권2호
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• pp.57-63
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• 1984

An inquiry approach in teaching science has been advocated by many science educators for the past few decades, and most elementary and secondary science curricula have incorporated it in varying degrees. It has been proven in recent studies, however, that there exists considerable discrepancy between the expectation of outcomes of the inquiry approach and the actuality. This in part implies that there is a somewhat urgent need for the systematic evaluation of the approach in teaching science. The purpose of this study is to develop a comprehensive instrument for evaluating inquiry teaching approaches embedded in science curricular materials. To develop a more valid and reliable instrument a set of empirical data was used in the developmental procedure, and most of the previous studies regarding inquiry teaching method and inquiry evaluation were consulted. The inquiry evaluation method developed in this study, called the Scientific Inquiry Evaluation Inventory (SIEI), is composed of three parts: (1) analyzing and coding each science process task of inquiry activity; (2) evaluating each inquiry activity as a whole; and (3) evaluating each science laboratory curriculum as a whole. The first part of the instrument consists of twenty science process categories and thirty subcategories grouped into four sections: (1) gathering and organizing data; (2) interpreting and analyzing data; (3) synthesizing results and evaluation; and (4) hypothesizing and designing an experiment. The science process categories are arranged according to the level of difficulty, psychological level of thinking, degree of creativity demand, and the model of the process of scientific inquiry, which is also developed in the study. The second part of the instrument contains four evaluation scales of inquiry activity: (1) competition/cooperation scale; (2) discussion scale; (3) openness scale; and (4) inquiry scope scale. And the last part consists of three methods for evaluating a science laboratory curriculum as a whole: (1) inquiry pyramid; (2) inquiry index; and (3) difficulty index. The instrument is designed to be used by teachers, science curriculum developers and science education evaluators for the purpose of diagnosing the nature and appropriateness of scientific inquiry introduced in secondary science curricular materials, especailly in laboratory work and field work.

• 정보처리학회논문지D
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• 제16D권4호
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• pp.613-620
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• 2009

소량으로 다품종을 생산하는 소규모 공장에서 적은 비용으로 쉽게 부품의 양 불량을 판별하는 시스템의 개발이 절실히 요구된다. 이러한 시스템의 개발을 위하여 다양한 환경에서도 물체를 인식할 수 있는 사람의 인식 능력과 같은 기능이 필요하다. 인간의 고등 지능은 대부분 두뇌의 신피질(neocortex)에서 비롯된다. 최근 이 신피질의 동작 원리를 컴퓨터에 접목시키는 연구 중의 하나가 Jeff Hopkins가 제안한 HTM 이론이다. 본 논문은 이 HTM 이론을 적용하여 소량 다품종 부품 생산 현장에서 부품의 이미지를 인식하여 양 불량을 판별하는 시스템인 PRESM(Parts image REcognition System for small scale Manufacturing industry)을 개발하였다. 개발 결과를 현장에 적용해 본 결과 실제 환경에서 부품의 양 불량 판별이 우수한 것으로 확인되었다.

• 디지털융복합연구
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• 제19권11호
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• pp.415-424
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• 2021

본 연구는 노년의 행복을 측정하기 위해 개발된 주관적 에이징웰 척도(Subjective Agingwell Scale: SAS)를 타당화하고자 하였다. 척도의 타당성을 검증하기 위해, 수도권에 거주하는 노인을 대상으로 주관적 에이징웰, 주관적 안녕감, 낙관주의, 지각된 통제력, 건강준수 행동을 측정하는 질문지를 실시하였다. 자료 분석에는 최종 342명의 응답결과가 사용되었다. 결과를 살펴보면, 첫째, 신뢰도 분석결과, 11문항의 SAS의 전체 및 하위 척도 신뢰도는 수용할만한 수준이었다. 둘째, 확인적 요인분석 및 상관분석 결과, SAS는 구성타당도가 있는 것으로 나타났다. 3요인(인지, 정서, 영) 구조의 적합도는 양호한 편이었고, 주관적 에이징웰과 주관적 안녕감, 낙관성은 정적 상관을 보였다. 마지막으로 회귀분석 결과, 주관적 에이징웰은 건강행동 준수를 예측하였고 준거타당도가 지지되었다. 본 연구는 주관적 관점의 에이징웰 측정도구를 국내 노인에게 적용할 수 있도록 타당화했다는 점에서 의미가 있다.

• Journal of Radiation Protection and Research
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• 제48권1호
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• pp.28-43
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• 2023

Background: High-fidelity meteorological data is a prerequisite for the realistic simulation of atmospheric dispersion of radioactive materials near nuclear power plants (NPPs). However, many meteorological models frequently overestimate near-surface wind speeds, failing to represent local meteorological conditions near NPPs. This study presents a new high-resolution (approximately 1 km) meteorological downscaling method for modeling short-range (< 100 km) atmospheric dispersion of accidental NPP plumes. Materials and Methods: Six considerations from literature reviews have been suggested for a new dynamic downscaling method. The dynamic downscaling method is developed based on the Weather Research and Forecasting (WRF) model version 3.6.1, applying high-resolution land-use and topography data. In addition, a new subgrid-scale topographic drag parameterization has been implemented for a realistic representation of the atmospheric surface-layer momentum transfer. Finally, a year-long simulation for the Kori and Wolsong NPPs, located in southeastern coastal areas, has been made for 2016 and evaluated against operational surface meteorological measurements and the NPPs' on-site weather stations. Results and Discussion: The new dynamic downscaling method can represent multiscale atmospheric motions from the synoptic to the boundary-layer scales and produce three-dimensional local meteorological fields near the NPPs with a 1.2 km grid resolution. Comparing the year-long simulation against the measurements showed a salient improvement in simulating near-surface wind fields by reducing the root mean square error of approximately 1 m/s. Furthermore, the improved wind field simulation led to a better agreement in the Eulerian estimate of the local atmospheric dispersion. The new subgrid-scale topographic drag parameterization was essential for improved performance, suggesting the importance of the subgrid-scale momentum interactions in the atmospheric surface layer. Conclusion: A new dynamic downscaling method has been developed to produce high-resolution local meteorological fields around the Kori and Wolsong NPPs, which can be used in short-range atmospheric dispersion modeling near the NPPs.

• Ocean and Polar Research
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• 제25권1호
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• pp.63-74
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• 2003

The build-up of the heat field in shallow coastal water due to a point source has been investigated using an analytical solution of a time-integral form derived by extending the solutions by Holley(1969) and also presented in Harleman (1971). The uniform water depth is assumed with non-isotropic turbulent dispersion. The alongshore-flow is assumed to be uni-directional, spatially uniform and oscillatory. Due to the presence of the oscillatory alongshore-flow, the heat build-up occurs in an oscillatory manner, and the excess temperature thereby fluctuates in that course and even in the quasi-steady state. A series of calculations reveal that proper choices of the decay coefficient as well as dispersion coefficients are critical to the reliable prediction of the excess temperature field. The dispersion coefficients determine the absolute values of the excess temperature and characterize the shoreline profile, particularly within the tidal excursion distance, while the decay coefficient determines the absolute value of the excess temperature and the convergence rate to that of the quasi-steady state. Within the e-folding time scale $1/k_d$ (where $k_d$ is the heat decay coefficient), heat build-up occurs more than 90% of the quasi-steady state values in a region within a tidal excursion distance (L), while occurs increasingly less the farther we go to the downstream direction (about 80% at 1.25L, and 70% at 1.5L). Calculations with onshore and offshore discharges indicate that thermal spreading in the direction of the shoreline is reduced as the shoreline constraint which controls the lateral mixing is reduced. The importance of collecting long-term records of in situ meteorological conditions and clarifying the definition of the heat loss coefficient is addressed. Interactive use of analytical and numerical modeling is recommended as a desirable way to obtain a reliable estimate of the far-field excess temperature along with extensive field measurements.