• Journal of Korean Elementary Science Education
• /
• v.36 no.1
• /
• pp.95-112
• /
• 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
• /
• v.29 no.2
• /
• pp.117-120
• /
• 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.

• Journal of Advanced Navigation Technology
• /
• v.24 no.1
• /
• pp.53-60
• /
• 2020

In this paper, We have studied the structure of a Telemetry Transmitter capable of transmitting variable data rates. This paper proposed a structure combining variable pre-modulation filter with cutoff characteristic with variable input sample rate converter. Variable pre-modulation filter has the same characteristics as pre-modulation filter and is converted to a constant sampling rate without structural changes according to the variable input data rate. We propose a software program that actively controls variable pre-modulation filter and variable input sample rate converter to respond to real-time changing data.

• Communications of Mathematical Education
• /
• v.32 no.1
• /
• pp.59-77
• /
• 2018

This study aims to investigate reflections of secondary pre-service mathematics teachers and their changes through practicing as assistant teacher in mathematics classrooms. For the purpose of this study, research questions are addressed on the reflections and their changes. During the 2015 Spring semester, secondary pre-service mathematics teachers took a course related to working as assistant teachers in regular mathematics lessons in a middle school. This study selected cases of two pre-service teachers. The data such as reports on their practices and final meeting report with teachers were collected during the semester. The results showed that the secondary pre-service mathematics teachers reflected teachers, students, mathematics contents, and themselves in their reports. In addition, each participant showed different contents of reflections. This difference implied that secondary pre-service mathematics teachers could have different reflections according to the types of lessons that they participated in.

• Journal of Broadcast Engineering
• /
• v.24 no.1
• /
• pp.105-117
• /
• 2019

Current Android smartphones include about 25 to 35 essential applications(unerasable) related to function and operation of the android smartphone itself and about 30 optional applications(removable) provided by carriers, Google and manufacturers. These applications were not able to be removed until the announcement of the smartphone applications pre-install guide from the government in January 2014, so there were memory limitations in installing new applications, causing consumer complaints by consuming data during the auto-update process of the pre-installed applications. After the announcement, we were able to delete optional applications but the complaints about the data consumption still did not disappear. Therefore, in this paper, we carried out the customer survey and analyzed the behavior information such as how carriers are operating pre-installed applications and what kind of applications customer prefers and how many applications customer wants to be pre-installed. And we proposed how to configure pre-install applications on smartphone for customer needs.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.1
• /
• pp.1-9
• /
• 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
• /
• v.10 no.4
• /
• pp.19-23
• /
• 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
• /
• v.3 no.3
• /
• pp.208-211
• /
• 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.

• Korean Journal of Veterinary Research
• /
• v.7 no.1
• /
• pp.1-7
• /
• 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
• /
• v.6 no.5
• /
• pp.401-415
• /
• 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.