• Journal of The Korean Association For Science Education
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• v.34 no.7
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• pp.625-634
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• 2014

This study has investigated the factors that make a science teacher effective by analyzing students' perception of teacher knowledge required in enhancing their science learning. The basic components of teacher knowledge identified by previous researchers have been confirmed through Exploratory Factor Analysis (EFA). Based on the findings of the EFA, the questionnaire has been further analyzed using Confirmatory Factor Analysis (CFA) by means of Structural Equation Modeling (SEM). In addition, the differences in students' perception on the identified factors of effectiveness have also been analyzed in terms of gender and achievement level. The findings of the EFA showed that five factors of science teacher effectiveness were identified; namely, substantive knowledge, syntactic knowledge, knowledge of students' understandings, knowledge of instructional strategies, and knowledge of assessment. These five components have been divided into two categories of teacher knowledge, SMK and PCK. What we found from the CFA was the respective high correlation between substantive and syntactic knowledge, knowledge of students' understanding and instructional strategies and the low correlation between substantive knowledge and knowledge of instructional strategies. Students perceived substantive knowledge as the most effective factor, knowledge of assessment as the least effective factor. Also, there have been considerable differences in students' perception by gender and achievement level. We proposed, based on the findings, that SMK and PCK need to be integrated into a coherent manner for the effective science teaching practice. This study provides some implications for science teacher professional development and the improvement of science teacher preparation program.

• Journal of Korea Water Resources Association
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• v.47 no.3
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• pp.223-235
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• 2014

In recent, the various methods to predict the hydrological impacts due to climate change have been developed and applied. Especially the trend analysis using observed and future hydrological data has been performed than ever. Parametric or non-parametric tests can be applied for a trend analysis. However, the non-parametric tests have been commonly used in the case of trend analysis using hydrological data. Therefore, the two types of non-parametric tests, Mann-Kendall (MK) test and Spearman Rho (SR) test, were used to detect the trend in the observed and future rainfall data that were collected from the Nakdong River basin. Also, the Pre-Whitening (PW) and the Trend Free Pre-Whitening (TFPW) as the pre-process of the trend analysis were performed. Also, the result of trend analysis suggest that those pre-processes have a statistically significant effect. Additionally, the Sequential Mann-Kendall (SMK) was used to reveal the beginning point of a trend in the observed and future rainfall data in the Nakdong River basin. The rainfall patterns in most rainfall gauges using the observed rainfall show the increasing trend and the abrupt changes in the specific months (from April to May and September to October). Also, the beginning point of the trend is brought forward by several months when climate change is accelerated. Finally, the results of this study can provide the useful background for the research related to climate change and water resources planning in the Nakdong River basin.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.565-570
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• 2010

Evapotranspriation (ET) was measured by eddy covariance method in two key ecosystems in Korea: the Seolmacheon site (a mixed forest in a complex terrain, SMK) and the Cheongmicheon site (a homogeneous rice paddy, CRK). By using the multi-year observations (SMK: Sep. 2007 - Dec. 2009, CRK: Aug. 2008 - Dec. 2009), we quantified ET and analyzed its temporal variations and control mechanisms based on the radiatively coupled combination equation. During the study period, the accumulated precipitation was about 3213 mm for the SMK site, of which about 30% (i.e., 990 mm), returned to the atmosphere as ET. At the CRK site from Jan. - Dec., 2009, the annual ET was 553 mm, which was about 40% of the annual rainfall (of 1401 mm). Both sites showed a characteristic seasonality with mid-season depression in ET that are associated with the reduced amount of available energy during the monsoon season. The decoupling parameter (${\Omega}^*$), which indicates the measure of interaction between vegetation and the atmosphere, averaged about 0.4 for the SMK site and the CRK site during the growing season. The ET from both sites was more influenced by air saturation deficit and surface conductance than available energy.

• Journal of Korea Water Resources Association
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• v.49 no.11
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• pp.903-912
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• 2016

Accurate understanding and estimating Evapotranspiration (ET) is essential for understanding the mechanism of water cycle and water budget. ET has been analyzed by many researchers in worldwide while Ground-based ET has limiation in analyzing the spatio-temporal pattrens of ET. Thus, many researches have been conducted to represent the spatio-temporal variation of ET by using hydrometeorological variables estimated from remote sensing datasets. Previous remote sensing based ET algorithms, however, have disadvantage in that various hydrometeological input datasets were required. In this study, actual ET was estimated by MODIS-based Rn and MS-PT algorithm requiring relatively less input data than previous method. The result confirmed that the observed $R_N$ and latent heat flux from the eddy-covariance based fluxtowers located at CFK and SMK showed high correlation with the estimated $R_N$ and ET. The average determination coefficients ($R^2$) of ET estimated from satellite dataset over study periods were 0.77 (0.72-0.81) in Cheongmi (CFK) and 0.70 (0.67-0.78) in Sulma (SMK), respectively. Comparing with the actual ET of two flux tower sites, however, SMK showed more overestimated patterns than CFK due to the vegetation and radiation related errors.

• Journal of Korea Water Resources Association
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• v.49 no.3
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• pp.227-239
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• 2016

This study is to estimate Surface Energy Balance Algorithm for Land (SEBAL) daily spatial evapotranspiration (ET) comparing with eddy covariance flux tower ET in Seolmacheon mixed forest (SMK) and Cheongmicheon rice paddy (CFK). The SEBAL input data of Albedo, Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) from Terra MODIS products and the meteorological data of wind speed, and solar radiation were prepared for 2 years (2012-2013). For the annual average flux tower ET of 302.8 mm in SMK and 482.0 mm in CFK, the SEBAL ETs were 183.3 mm and 371.5 mm respectively. The determination coefficients ($R^2$) of SEBAL ET versus flux tower ET for total periods were 0.54 in SMK and 0.79 in CFK respectively. The main reason of SEBAL ET underestimation for both sites was from the determination of hot pixel and cold pixel of the day and affected to the overestimation of sensible heat flux.

• Journal of Korea Water Resources Association
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• v.52 no.1
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• pp.11-19
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• 2019

In this study, the actual evapotranspiration products of Global Land Data Assimilation System (GLDAS), Global Land Evaporation Amsterdam Model (GLEAM) and MOD16, which are satellite- and reanalysis-based dataset, were validated at the flux tower sites (i.e., CFK and SMK) managed by Korea Institute of Hydrological Survey, and the uncertainty and correlation analysis were conducted using Triple Collocation (TC) method. The result of validation with the flux tower showed better agreement in the order of GLEAM> GLDAS>MOD16. At the result of three combinations (S1: flux tower vs. GLDAS vs. MOD16, S2: flux tower vs. GLDAS vs. GLEAM, S3: flux tower vs. GLEAM vs. MOD16), the order of best to worst is GLEAM, GLDAS, MOD16, and flux tower for CFK (GLDAS> GLEAM>MOD16>flux tower for SMK). Since the error variance and correlation coefficients of the flux tower show relatively worse performance in TC analysis than the other products, By applying TC method to three products (GLDAS vs. GLEAM vs. MOD16), the uncertainty of each dataset were evaluated at the Korean Peninsula, As a results, the GLDAS and GLEAM performed reasonable performance (low error variance and high correlation coefficient), whereas results of MOD16 showed high error variance and low correlation coefficient at the cropland.

• Journal of the Korean earth science society
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• v.38 no.5
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• pp.378-392
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• 2017

Teacher quality is a topic of international concern, as it impacts student learning and teacher preparation. This study compared the undergraduate secondary science teacher preparation programs from two universities in Korea with those of Oregon, USA. We examined the programs' structural curricular coherence, conceptual curricular coherence, and curricular balance. Structural curricular coherence was determined by examining the overarching goals of the institutions' programs, the organization of the programs of study in terms of meeting those goals, and outside bodies of evidence. All universities were in structural coherence for various reasons. Conceptual curricular coherence was determined by examining students' perceptions of the connection between their preparation and their clinical practice. In case of Korea, most students from both universities were not satisfied with their practical preparation. In the US, the students from both institutions felt well prepared to transition to inservice teaching. To determine curricular balance, we examined the institutions' preparation programs looking at the credit hours taken in the four main areas of the teacher knowledge base: GPK (General Pedagogical Knowledge), SMK (Subject Matter Knowledge), PCK (Pedagogical Content Knowledge), and CK (Contextual Knowledge). The total credit hours taken in each category was very similar by country but the application and field component in the USA was far greater than those of Korea where the focus was heavily on SMK and PCK. The main reason for these may be the nations' licensing and employment processes.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.56-63
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• 2015

The optimization is an important role in wide geographical distribution of electrical power market, finding the optimum solution for the operation and design of power systems has become a necessity with the increasing cost of raw materials, depleting energy resources and the ever growing demand for electrical energy. In this paper, the real coded biogeography based optimization is proposed to minimize the operating cost with optimal setting of equality and inequality constraints of thermal power system. The proposed technique aims to improve the real coded searing ability, unravel the prematurity of solution and enhance the population assortment of the biogeography based optimization algorithm by using adaptive Gaussian mutation. This algorithm is demonstrated on the standard IEEE-30 bus system and the comparative results are made with existing population based methods.

• The Korean Journal of Mycology
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• v.27 no.2 s.89
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• pp.147-157
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• 1999

This paper is the eighth contribution towards taxonomic studies on Cercospora and allied genera, and contains ten species of Korean cercosporoid fungi; viz., Cercospora brassicicola, C. flagellaris, C. sesami, C. zinniae, Passalora amurensis, Pseudocercospora balsaminae, P. humuli, P. puderi, P. salicina, and Stenella dianthi. Morphological characteristics of taxonomic value are described and illustrated for these species to contribute towards a mycological monograph of Korean cercosporoid fungi.

• The Korean Journal of Mycology
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• v.27 no.2 s.89
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• pp.138-146
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• 1999

This paper is the seventh contribution towards taxonomic studies on Cercospora and allied genera, and contains ten species of Korean cercosporoid fungi; viz., Cercospora arcti-ambrosiae, C. cichorii, C. kikuchii, C. subhyalina, Neoramularia koreana, Pseudocercospora ligustri, P. oenotherae, P. rubi, P. zelkowae, and Ramularia archangelicae. Morphological characteristics of taxonomic value are described and illustrated for these species to contribute towards a mycological monograph of Korean cercosporoid fungi.