• Journal of the Korean Magnetics Society
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• v.2 no.2
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• pp.105-113
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• 1992

조성이 Mn$_{x}$Zn$_{1-x}$ Fe$_{2}$O$_{4}$ 훼라이트(x=0.75, 0.52)를 pusher type 연속 전기로를 이용하여 질소 분위기하에서 1360 .deg. C 로 3시간 동안 소결하여 얻어냈다. 본 연구에서는 스피넬 구조인 Mn-Zn 훼라이트의 FMR(Ferrimagnetic Resonance) 스펙트럼 특징과 초기투자율과의 상관성을 조사하고자 EPR X-band 스펙 트로미터를 이용 9.50 GHz의 microwave frequency에서 FMR 실험을 수행하였다. FMR 공명흡수선은 주 자기공명 흡 수선외에 낮은 자기장에서 약한 subsidiary 공명흡수선을 나타내는데 온도변화에 따른 주 자기공명 흡수선과 sub- sidiary 공명흡수선(제2, 제3 공명흡수선)의 세기, 공명선폭, g값 등의 온도 의존성을 연구함으로써 제2 공명흡수 선이 나타나는 원인을 분석하였으며, 자기공명 흡수선의 g값, 자기공명선 세기, 그리고 공명선폭과 초기투자율의 상관성을 연구하였다. 실험 결과 주 자기공명 흡수선의 g값, 자기공명선 세기, 공명선폭은 초기투자율 값과 밀접 한 관련이 있음을 확인할 수 있었다.었다.

• Journal of The Korean Association For Science Education
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• v.20 no.2
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• pp.288-296
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• 2000

In this study, the types and the characteristics of students' responses to anomalous data were investigated. The criteria for classifying students' responses were 'acceptance of validity of anomalous data', 'acceptance of inconsistency between anomalous data and initial theory', and 'change of belief in initial theory'. Seven types of responses were identified as follows: Rejection, reinterpretation, exclusion, uncertainty, peripheral theory change, partial belief change, and theory change. Absolute belief in the intial theory and doubts about methodological accuracy were found to be the major reasons for rejecting anomalous data. The students did not accept the inconsistency between anomalous data and initial theory because they ignored the experimental procedures and focused on the similarity of the experimental results.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.2
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• pp.103-114
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• 1992

A study result of buckling reliability is presented for the axially compressed imperfect elastic cylinder. Multi-mode analysis program is developed from Karman-Donnell Equation for the calculation of the buckling load of the cylindrical she1l. Geometric intial imperfection is approximated by double Fourier series of which coefficients are assumed random variables with jointly normal distribution characteristics. Crude Monte Carlo simulation technique is used to calculate the probabilistic failure properties of several cases with various imperfection Conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.447-451
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• 2017

하천은 지역별, 하천별 고유한 유역형상과 유출특성을 갖고 있어 계획과 관리를 위한 계획하폭 산정공식은 지역고유의 수문학적, 지역적 특성에 따라 달라야 하지만, 현재 적용되고 있는 설계기준의 계획하폭 산정공식은 최근 강우 경향 및 하천 주변 토지이용 고도화 등의 지역특성 여건변화가 고려되지 못하고 있는 실정이다. 특히 소하천의 경우에는 중 대규모의 하천과 달리 계획하폭 산정을 위한 지역별 매개변수의 편차가 커기존 산정된 공식을 활용함에 있어 어려움이 따르며, 토지이용 효율성 및 치수 경제성이 낮은 비효율적 계획하폭이 결정될 개연성이 있는 것으로 판단된다. 따라서 본 연구에서는 한반도 내륙기후특성을 가지는 강원영서지역 소하천에 대한 초기계획하폭 제안식을 산정하기 위해 계획홍수량(Q), 유역면적(A), 하상경사(S)에 대한 회귀분석을 실시하였다. 이를 통해 산정된 관계식은 기초 매개변수만 가지고 쉽게 초기계획하폭을 산정할 수 있어 지역 및 하천특성에 부합되는 개수계획 수립에 활용할 수 있다.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.86-95
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• 2018

The objective of this study was to describe the development and testing of an initial ecological health assessment model, based on the index of biological integrity (IBI) using fish assemblages, before establishing the final and currently used model for ecological health assessment, conservation and management of freshwater fish in Korea. The initial fish IBI model was developed during 2004~2006 and included 10 metrics, and in 2007 the final IBI 8-metric model was established for application to streams and rivers in four major Korean watersheds. In this paper, we describe how we developed fish sampling methods, determined metric attributes and categorized tolerance guilds and trophic guilds during the development of the multi-metric model. Two of the initial metrics were removed and the initial evaluation categories were reduced from six to four (excellent, good, fair, poor) before establishing the final national fish model. In the development phase, IBI values were compared with chemical parameters (BOD and COD as indicators of organic matter pollution) and physical habitat parameters to identify differences in IBI model values between chemical and physical habitat conditions. These processes undertaken during the development of the IBI model may be helpful in understanding the modifications made and contribute to creating efficient conservation and management strategies for stream environments to be used by limnologists and fish ecologists as well as stream/watershed managers.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.1
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• pp.49-56
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• 2014

This study was conducted to investigate the biodegradation characteristics of swine and cattle using anaerobic batch tests. The results showed that the maximum methane production rate($MPR_{max}$) and acclimation time(AT) of swine were 46.7 mL $CH_4/g$ VS.d and 17.2 d, respectively. The $MPR_{max}$ and AT of cattle were 56.5% and 24.0% lower than those of swine. The characteristics of anaerobic biodegradation varied with livestock species but $MPR_{max}$ and AT increased linearly with the content of lipid. The $MPR_{max}$ and AT of cattle with content of lipid were more sensitive than those of swine.

• Korean Journal of Cognitive Science
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• v.17 no.1
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• pp.53-74
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• 2006

Similarity has been considered as one of basic concepts of cognitive psychology which is useful for explaining cognitive structure and process. MDS models(Shepard, 1964; Nosofsky, 1991) and Contrast model(Tversky, 1977) were proposed as early models of similarity comparison process. But, there have been a lot of theoretical doubts about the conceptual validity of similarity as a result of empirical findings which could not be explained by early models. Goldstone(1994) assumed that similarity could be defined by alignment processes, and suggested structural alignment as a prospective alternative for solving conceptual controversies so far. In this study, basic assumption and algorithms of MDS models(Shepard, 1944; Nosofsky, 1991) and Contrast model(Tversky, 1977) were described shortly and some theoretical limitations such as arbitrariness of selective attention and correlated structures were discussed as well. The conceptual characteristics and algorithms of SIAM(Goldstone, 1994) were described and how it has been applied to cognitive psychology areas such as categorization, conceptual combination, and analogical reasoning were reviewed. Finally, some theoretical limitations related with data-driven processing and alternative processing and possible directions for structural alignment were discussed.

• Journal of Korean Library and Information Science Society
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• v.53 no.4
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• pp.293-318
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• 2022

The purpose of this study is to analyze the impact of reading on self-efficacy and multicultural acceptance. The Korean Education and Employment Pannel II data were used for the analysis. Through analyzing the data with latent growth model, the growth trajectories for reading, self-efficacy, and multicultural acceptance were identified, and the relationship between three variances were analyzed using multi-variate latent growth model. As results, reading books, self-efficacy, and multicultural acceptance were decreased, as times go by. Next, the intercept of reading was postively related with self-efficacy and multicultural acceptance. Finally, self-efficacy mediated between the intercept of reading and the multicultural acceptance, and it's statistically significant.

• Journal of the Korean Geotechnical Society
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• v.31 no.8
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• pp.51-62
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• 2015

It is not possible to provide resonable evidence for embankment (or dam) overtopping in geotechnical engineering, and conventional analysis by hydrologic design has not provided the evidence for the overflow. However, hydrologic design analysis using Copula function demonstrates the possibility that dam overflow occurs when estimating rainfall probability with rainfall data for 40 years based on fluctuating water level of a dam. Hydrologic dam risk analysis depends on complex hydrologic analyses in that probabilistic relationship needs to be established to quantify various uncertainties associated with modeling process and inputs. The systematic approaches to uncertainty analysis for hydrologic risk analysis have not been addressed yet. In this paper, the initial level of a dam for stability of a dam is generally determined by normal pool level or limiting the level of the flood, but overflow of probability and instability of a dam depend on the sensitivity analysis of the initial level of a dam. In order to estimate the initial level, Copula function and HEC-5 rainfall-runoff model are used to estimate posterior distributions of the model parameters. For geotechnical engineering, slope stability analysis was performed to investigate the difference between rapid drawdown and overtopping of a dam. As a result, the slope instability in overtopping of a dam was more dangerous than that of rapid drawdown condition.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.287-298
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• 2018

This study, a second analysis research using raw data of the 6th Korea National Health and Nutrition Examination Survey(2013-015), places its purpose on examining risk factors for the mental health of the youth. With its target on 3,712 people in their twenties and thirties, it has used complex sample cross analysis to figure out the relationship between their mental health and eating habits. Also, it has carried out multiple logistic regression analysis for the purpose of grasping the youth's mental health risk factors. Under the circumstances, controlling the subjects' individual characteristics, the study has shown that males with their breakfast and dinner partners have lower possibilities of depression and suicidal thoughts. Meanwhile, in the case of females, their breakfast and lunch partners have played a key role in lowering their stress and suicidal thoughts. Given these results, the government will have to make all-out efforts to upgrade public places and spaces for the youth to eat together. All this will lead to their healthy eating habits and positive mental health. More specifically, it will have to create variable programs necessary for educating them to manage their diet and enjoy eating with other people.