• 한국초등과학교육학회지:초등과학교육
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• 제36권1호
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• pp.95-112
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• 2017

The competence of teachers, comes out through their lesson, is one of the key factors of school education. The purpose of this study is comparing the viewpoints on the science lessons in the elementary classrooms between pre-service teachers and highly experienced teachers in order to draw implications on pre-service teacher educating system. The participants of the study are 14 junior students in a university of education and 9 elementary school teachers who are highly educated and have much career experience. Each student participant observed one video clip with science lesson of their classmate. The total number of the video subject to observation is 4. Meanwhile experienced teachers observed 1 or 2 videos which are the same to those the students watched. The participants made a class criticism according to the General Standards for Class Critique made by KICE. The in-depth analysis of the criticism yielded the following conclusions; First, pre-service teachers had narrow views on the science class mainly limited in the practical part of class, but experienced teachers had wide views covered to class-knowledge, plan, and practice. Second, most experienced teachers thought that learning is the process by which students acquire knowledge or concepts by themselves, and the main purpose of the class is to help students' learning. Meanwhile, there were many pre-service teachers who thought that conveying knowledge or concepts to students was the main purpose of the class. Third, experienced teachers thought that a good science class should maintain consistency around the learning goals from the planning, implementation, and evaluation. However, many pre-service teachers did not take the learning objectives so seriously.

• Reproductive and Developmental Biology
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• 제29권2호
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• pp.117-120
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• 2005

This study was conducted to establish the optimal temperature condition before oocyte activation in B6m F1 mouse. In experiment 1, two embryo culture media (CZB vs KSOM) were evaluated for the development of activated mouse oocytes. Parthenogenetic embryos cultured in KSOM showed better blastocyst development than ones cultured in CZB $(56.2\%\;vs\;81.0\%\;p<0.01)$. Two-hour of pre-incubation before activation significantly reduced the number of hatched blastocysts in KSOM $(22.0\%\;versus\;8.8\%\;p<0.05)$. In experiment 2, recovered oocytes were pre-incubated at different temperature conditions before activation. The experimental groups were divided by 5 as follows. Group A: pre-incubation for 120 min at $37^{\circ}C$, Group B: pre-incubation at $37^{\circ}C$ for 90 min then at $25^{\circ}C$ for 30 min, Group C: pre-incubation at $37^{\circ}C$ for 60 min then at $25^{\circ}C$for 60 min, Group D: pre-incubation at $37^{\circ}C$ for 30 min then at $25^{\circ}C$ for 90 min, and Group E: pre-incubation at $25^{\circ}C$ for 120 min before activation. Group A $(67.6\%)$ and B $(66.7\%)$ showed better development to the blastocyst stage than other groups $(Group\;C:\;50.0\%\;Group \;D:\;49.2\%\;Group\;E:\;33.3\%,\;p<0.05)$. The present study indicates that the temperature before activation affects the development of B6D2 F1 mouse parthenogenetic oocytes and exposure to room temperature should be limited to 30-min when the oocytes are left in HEPES-buffered medium for micromanipulation.

• 한국항행학회논문지
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• 제24권1호
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• pp.53-60
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• 2020

본 논문에서는 가변 데이터 전송 가능한 텔레메트리 송신기의 구조에 대해 연구하였다. 가변 데이터 전송을 위하여 가변 컷오프 특성을 가지는 VPMF (variable pre-modulation filter)와 가변입력 샘플레이트 변환기 (variable input sample rate converter)가 결합된 구조를 제안한다. VPMF는 일반적인 PMF (pre-modulation filter)와 동일하게 변조 전 신호의 고주파 성분을 억제하여 RF (radio frequency)신호의 대역을 제한하는 특성을 지니며, 추가적으로 입력 데이터율에 따라 가변 컷오프 특성을 갖는다. 가변입력 샘플레이트 변환기는 입력 데이터율 변경 시 추가적인 구조변경 없이 입력 데이터율과 무관하게 출력을 일정한 샘플링 속도로 변환하는 기능을 갖는다. 추가적으로 실시간 변화하는 데이터양에 대응하기 위해 VPMF와 가변입력 샘플레이트 변환기를 능동적으로 제어하는 소프트웨어 프로그램 기법을 제안한다. 제안 방법을 적용하여 시뮬레이션과 실제 제작을 통하여 입력 데이터율 390 kbps ~ 25 Mbps 범위에서 IRIG (inter-range instrumentation group) 표준의 99% 전력 대역폭, null-to-null 대역폭, 1st IMD (inter modulation distortion) 비교 결과 규격을 만족하는 데이터 전송이 가능함을 확인하였다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제32권1호
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• pp.59-77
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• 2018

본 연구는 교원양성기관 프로그램에서 교육실습이 아닌 형태의 현장실습을 포함한 수업을 통한 중등예비수학교사의 반성과 그 변화에 대해 살펴보는 것이 목적이다. 이를 위해 정규 수학수업에서 학습보조교사 활동을 한 중등예비수학교사 2인을 대상으로 사례연구를 진행하였다. 2015년도 1학기 수업에 참여한 중등예비수학교사들의 학습보조교사 활동 보고서 및 간담회 등의 자료를 통해 반성내용을 분석하였다. 연구 결과 학습보조교사 활동을 한 중등예비수학교사의 반성내용은 교사, 학생, 교과내용, 자기 자신 순으로 많은 것으로 나타났고 시간이 지남에 따라 학생에 대한 반성이 증가하는 것을 확인하였다. 또한 중등예비수학교사가 참여한 수업의 형태에 따라 반성내용의 비율도 달라짐을 확인하였다.

• 방송공학회논문지
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• 제24권1호
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• pp.105-117
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• 2019

현 안드로이드 스마트 폰에는 통신사, 구글, 제조사들에 의해 제공되는 스마트폰 자체의 기능 및 운영과 관련된 약 25개~35개의 필수앱(삭제불가)과 30개 정도의 선택앱(삭제가능)들이 선탑재 되어있다. 이 앱들은 2014년 1월 정부로부터 스마트폰 앱 선탑재 가이드가 발표되기 이전에는 삭제할 수 없어 새로운 앱들을 설치하는데 메모리에 제한이 있었으며, 해당 앱들의 자동 업데이트 과정에서 데이터를 소모시켜 소비자의 불만을 발생시켰다. 발표 이후에는 선택앱들은 삭제할 수 있도록 하였으나 여전히 데이터 소모에 대한 불만은 사라지지 않아 선탑재 앱 구성에 대한 개선 논쟁은 계속되고 있다. 따라서 본 논문에서는 현재 통신사들의 앱 선탑재가 어떻게 운영되고 있으며, 선탑재된 앱들 중 소비자들은 어떤 앱을 선호하고 있으며, 몇 개를 원하는지 등의 행태정보를 데이터와 소비자 조사를 통해 분석하였다. 이를 통해 소비자 니즈에 맞는 스마트폰 선탑재 앱 구성방안에 대해 제안하였다.

• 한국운동역학회지
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• 제24권1호
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• pp.1-9
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• 2014

The purpose of this study was to investigate the muscle mechanical properties of the pelvic axial pre-rotational movement for the Jireugi in the Taekwondo Juchumseogi stance. Eleven elite Taekwondo Poomsae athletes participated. Each participant performed 5 right hand Jireugi in Juchumseogi stance as fast and strong as possible while their motion was recorded by a 3D motion analysis system and the ground reaction forces by two force plates. The power and work of the muscular group surrounding the waist were analyzed to verify the effect of the stretch-shortening cycle (SSC) theory. The cause of the greater power seems to be the application of the SSC by the muscles surrounding the waist during the preparation phase of the pre-rotation group. For the none pre-rotation group, they only used the concentric contraction of the muscles surrounding the waist. Because the pre-rotation group used the SSC theory, they had the effect of shortening of the range of movement, creating a fast and more powerful rotation, thus anticipating the increase the magnitude of impact.

• Journal of Nutrition and Health
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• 제10권4호
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• pp.19-23
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• 1977

It is said that a mode of dietary behavior changes together with socioeconomic and cultural transformation. Formation of dietary habit of pre-school children influences upon direction of this changes, specially. So, this study was planned to analyst the dietary pattern of pre-school children. A survey was carried out for 3 days of 28 pre-school children with a mean age of 4 years and 3 months. Each child's matter wrote dietary pattern and kinds of food as staple, subsidiary and snack. The results showed that; (1) the average meal frequency a day was 3.1 and interval between meal was 5.1 hours (for breakfast to lunch & lunch to supper) and 12.6 hours (for supper to breakfast), (2) there were 27 different kinds of foods as staple and cereal products consumed the most among those, and 82 different kinds of foods as subsidiary and KIMCHI products were eaten the most rating, (3) the average snack frequency a day was 5.0. There were 76 different kinds of foods as snack, among them cold drink was the best. The present observation suggested that pre-school children had a tendency to take meat regularly, but snack very irregularly, and kinds of foods taken as staple, subsidiary and snack didn't keep the nutritional balance. Parent's concern about dietary behavior of their children is demanded more than ever.

• Nutrition Research and Practice
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• 제3권3호
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• pp.208-211
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• 2009

This study investigated the effect of vitamin $B_6$ deficiency on antioxidant enzyme activities and lipid profile in rats with exercise-induced oxidative stress. Forty eight rats were fed either a vitamin $B_6$ deficient diet (B6-) or a control diet (control) for 4 weeks and then subdivided into 3 groups: pre-exercise (PreE); post-exercise (PostE); recess after exercise (recessE). Compared to those of control group, plasma catalase and hepatic cytosol superoxide dismutase (SOD, EC 1.15.1.1) activities of B6- group were lower regardless of exercise. The ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) of B6 - group was lower in PreE and there was no difference between PostE and recessE. The level of malondialdehyde (MDA) of B6- was significantly higher in PreE and PostE. High-density lipoprotein-cholesterol (HDL-C) level of B6- group was lower regardless of exercise. Atherosclerotic index of $B_6$- group was higher in PreE and there was no difference between PostE and recessE. It is suggested that a reduction in antioxidative status caused by vitamin $B_6$ deficiency may be aggravated under exercise-induced oxidative stress.

• 대한수의학회지
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• 제7권1호
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• pp.1-7
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• 1967

Clinically healthy Korean adult cattle (20 females and 20 males) were selected and subjected to the experiments on the determination of erythrocytes and total leukocytes values at the stages of pre and post-slaughting. Throughout the studies the following results were obtained. 1. The erythrocytes values, at the stage of the pre-slaughter, of females and males were $6.070{\times}10^6/cmm$ and $6.175{\times}10^6/cmm$ respectively. In the case of post-slaughter stage, $7.780{\times}10^6/cmm$ and $7.705{\times}10^6/cmm$ were obtained for female and male respectively. In comparison on the values of erythrocytes between pre and post-slauglnter stages, the mean value of the latter has been increased significantly. 2. The total leukocytes value, at the stage of the pre-slaughter of females and males were 9,525/cmm and 9,630/cmm respectively. In the case of post-slaughter stage, 7,545/cmm and 7,510/cmm were obtained for females and males respectively. In comparison on the values of total leukocytes between pre and post-slaughter stages, the mean value of the latter has been decreased significantly.

• Steel and Composite Structures
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• 제6권5호
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• pp.401-415
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• 2006

Based on a non-linear model taking into account flexural-torsional couplings, analytical solutions are derived for lateral buckling of simply supported I beams under some representative load cases. A closed form is established for lateral buckling moments. It accounts for bending distribution, load height application and pre-buckling deflections. Coefficients $C_1$ and $C_2$ affected to these parameters are then derived. Regard to well known linear stability solutions, these coefficients are not constant but depend on another coefficient $k_1$ that represents the pre-buckling deflection effects. In numerical simulations, shell elements are used in mesh process. The buckling loads are achieved from solutions of eigenvalue problem and by bifurcations observed on non linear equilibrium paths. It is proved that both the buckling loads derived from linear stability and eigenvalue problem lead to poor results, especially for I sections with large flanges for which the behaviour is predominated by pre-buckling deflection and the coefficient $k_1$ is large. The proposed solutions are in good agreement with numerical bifurcations observed on non linear equilibrium paths.