• Journal of The Korean Association For Science Education
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• v.17 no.4
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• pp.383-393
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• 1997

In order to study the effect of student's conceptions about force and motion into the graph construction in kinematics in college physics course, the tasks of constructing the qualitative graph in the similar problem context used in force conception was asked to the first 74 and third 97 student teacher in teachers' university. The frequencies analysis showed that student teachers had the naive conceptions that the throwing force was still acted to a upwarding ball. They also had the popular Aristotelian views about motion. These naive conceptions coexisted with the scientific conception about gravitational force. In a simple pendulum problem no one had the correct acceleration concepts which varies the direction in swing. This result suggest that student teacher had more difficulties in a acceleration problem than in a velocity problem In v-t and a-t graph construction tasks, the number of categories of a-t graphs were more than that of v-t graphs. There were many graph errors in a sign of velocity and acceleration. The acceleration conceptions without the relations of changes in velocity made the kinematics graphs more various shapes. The force and motion conceptions influenced the ability to construct the kinematics graphs.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.9 no.2
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• pp.13-23
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• 2003

본 연구의 목적은 손 기능에 문제가 있는 환자들을 중심으로 splint의 효과를 알아보기 위한 기초조사로써 2명의 환자를 제주 한마음병원(Case1, 2)에서 2001년 6월부터 11월까지 조사하였다. 2명의 환자는 다음과 같다. i) 사례 1 : 뇌성마비 아동(4세, 남, 오른손)으로 한쪽 손목과 엄지손가락에 강직으로 인하여 잡기 기능에 제한이 있는 편마비 아동이다. ii) 사례 2 : 전기화상(56세, 남, 왼손)으로 4-5번째 손가락의 M.P joint와 I.P joint에 관절운동 제한으로 완전하게 주먹을 질 수가 없다. 연구를 위하여 손 기능의 평가는 표준화가 되어있는 Jebsen-hand function test, Total passive Motion(TPM)을 사용하였으며, 환자들의 만족도를 알아보기 위해서는 Canadian Occupational Performance Measure(COPM)을 사용하였다. i) 사례 1 : 두 가지 splint를 적용하였다. 즉 낮 동안에는 splint 1, 밤 동안에는 splint 2를 6시간 이상 착용하도록 하였으며 작업치료는 시행하지 않았다. ii) 사례 2 : 이 환자에게는 작업치료가 끝나는 동시에 splint. 3을 6시간 이상 착용하도록 하였으며, M.P joint와 I.P joint의 관절 변화를 조절하도록 특별히 고안된 splint를 적용하였다. 그 결과 사례 1의 Jebsen-hand function test시 초기에는 측정을 할 수가 없었으나, splint착용 후 크고 가벼운 물건 옮기기(44.15), 크고 무거운 물건 옮기기(42.66), 적목쌓기(44.63), 먹기 흉내내기(54.47) 등에서 처음 동작만 도와주면 측정이 가능할 수 있도록 진전을 보였다(그래프1), 사진(착용 전과 착용 후). 사례 2의 경우 Jebsen-hand function test의 적목쌓기와 먹기 흉내기가 가장 높았으며, 글씨 쓰기가 가능했다. 손의 관절가동 변화에서도 splint 착용전의 측정치와 착용 후 관절 가동 범위의 변화 폭이 약 $30_{\circ}$이를 보여주었다(그래프 2), (그래프3). 결론적으로 손 기능 회복에 직접적인 재활 치료뿐만 아니라, 치료 후에도 splint를 착용하여 가정에서도 계속적인 치료가 될 수 있도록 하는 것이 손의 기능회복에 도움이 됨을 알 수 있었다. 그러므로 각 환자의 문제점을 파악하여 적절한 splint를 제작해 줄 필요가 있다고 사료된다. 이 기초조사를 시작으로 하여 더 많은 환자들을 대상으로 splint가 손 기능 회복에 어떠한 영향을 미치는지 그 효과에 대하여 계속적인 연구가 필요할 것이다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.538-542
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• 2015

The transverse moment of inertia is an indispensable factor in analyzing the roll motion characteristics of ships and the calculating method needs to be based on the more reasonable theories when deciding the value as the results and reliability of analysis could be much affected by the correctness. However, the mass distribution and shape of hulls are quite complicated and give much difficulties in case of calculating the value directly from the ship design data, furthermore even acquiring the detailed design data for calculation is almost impossible. Therefore some simpler ways are practically adopted in the assumption that the gyradius of roll moment can be decided by a given ratio and hull width. It is well known that the responses of the free roll decay are varied according to the value of roll moment in view of roll period and amplitude decay ratio, so that the general formula to get the moment value can be derived also from the observation of roll decay responses. This study presents how the roll period and decay ratio are interrelated each other from the roll motion characteristics with suggesting a general formula to be able to calculate roll moment from it. Finally, the obtained general formula has been applied to a ship data to check the resultant characteristics through analyzing graphs and showed that the roll moment becomes more accurate when rolling period and decay ratio are considered together in calculation.

• The Journal of the Acoustical Society of Korea
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• v.14 no.5
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• pp.29-35
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• 1995

Nonlinear distortion arising from the nonlinear movement of the loudspeaker diaphragm degradates the tone quality. The distortion is, in low frequency range, mainly caused by nonlinear characteristics of the suspension stiffness and the force factor. In this paper, the nonlinear suspension stiffness and the nonlinear force factor are modeled to the quadratic functions and a method is proposed to determine their coefficients. An additional mass to the diaphragm moved the quiescent point of the diaphragm and uncoupled the stiffness and the force factor. This made it possible to deter mine the coefficients of the nonlinear suspension stiffness by measuring the resonance frequencies at several quiescent points. The coefficients of the nonlinear force factor are then determined by fitting the curve which is calculated from the waveforms of input voltage and input current, and the displacement of the diaphragm at resonance frequency.

• Journal of Korean Elementary Science Education
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• v.31 no.3
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• pp.386-397
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• 2012

The purpose of this study was to find a way to improve the science textbook graph through analyzing teachers' interpretation process with eye movement tracking when they try to read the science textbook graph. Participants in this project were 10 elementary school teachers while bar graphs, line graphs, pie charts in 2007 revision science textbooks were used as materials. SMI (SensoMotoric Instruments)' iView X TM RED 120 Hz was used in order to collect eye movement data. Although subjects paid attention to the title of the graph at first, the consequence of the eye fixation was changed by the composition of the graph in case of the rest of areas. In particular, the flow of visual attention and fixation time were affected by the form and configuration of the graph. The diversity of graph construction caused confusion in interpreting graphs; the manner of presenting title, the difference of background colors, size of characters, the name of X-axis and Y-axis. Out results showed that the conformation of graphs as well as the presentation of each factor should be composed in accordance with the educational purpose for helping users to easier understanding.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.4
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• pp.27-34
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• 2005

The paper discussed on the stability of cantilevered pipe conveying fluid subjected to distributed follower force. Governing equations of motion are derived by extended Hamilton's principle, and the numerical scheme using finite element method is applied to obtain the discretized equations. The critical flow velocity as a function of the distributed follower force for the various mass ratio is determined. The flutter configurations of the pipes at the critical flow velocities are drawn graphically at every twelfth period to define the order of quasi-mode of flutter configuration The critical mass ratios, at which the transference of the eigenvalue branches related to flutter take place, are definitely determined. Also, the effect of damping on the stability of the system is considered.

• The Journal of Korean society of community based occupational therapy
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• v.4 no.2
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• pp.11-22
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• 2014

Objective : The purpose of this study is to investigate the effect of mental practice with task activities through upper limbs movement speed and accuracy in ideomotor apraxia patient. Methods : As a single subject research design with multiple baseline across individuals, the patients were two ideomotor apraxia patients, employed in this study. The employed program included receiving mental practice and task activities, measuring change of the total performance times, time to put down the last cups and amount of water in cups for 4 weeks, including baseline and intervention periods. The subject were measured by Ideomotor apraxia test and MFT were analyzed. The analyses were performed using visually and two-standard deviation band method. Results : All subjects were a reduction in symptoms of apraxia, but noticeable change in upper limbs function was not there. Total time of performance from 376.67 to 355.24 seconds, 391.33 seconds to 434.60 seconds, reduced. Put down the cup of performance time from 15.67 to 13.30 seconds, 20.80 seconds to 10.73 seconds, reduced. The amount of water transferred from 52.38ml to 49.70ml, 50.89ml to 50.09ml, all results were closer to 50ml. Conclusion : As a result of this study, mental practice with task activities can be an effective method to ideomotor apraxia patients. This study would serve a fundamental data on ideomotor apraxia patients to the further studies.

• Journal of Korean Elementary Science Education
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• v.41 no.4
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• pp.658-672
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• 2022

The unique teaching and learning difficulties of speed-related units in elementary school science are mainly due to the student's lack of mathematical thinking ability and procedural knowledge on speed measurement, and curriculums and textbooks must be constructed with these in mind. To identify the implications of composing a new science curriculum and relevant textbooks, this study reviewed the structure and contents of the speed-related units of three curriculums from the 2007 revised curriculum to the 2015 revised curriculum and the resulting textbooks and examined their relevance in light of the literature. Results showed that the current content carries the risk of making students calculate only the speed of an object through a mechanical algorithm by memorization rather than grasp the multifaceted relation between traveled distance, duration time, and speed. Findings also highlighted the need to reorganize the curriculum and textbooks to offer students the opportunity to learn the meaning of speed step-by-step by visualizing materials such as double number lines and dealing with simple numbers that are easy to calculate and understand intuitively. In addition, this paper discussed the urgency of improving inquiry performance such as process skills by observing and measuring an actual object's movement, displaying it as a graph, and interpreting it rather than conducting data interpretation through investigation. Lastly, although the current curriculum and textbooks emphasize the connection with daily life in their application aspects, they also deal with dynamics-related content somewhat differently from kinematics, which is the main learning content of the unit. Hence, it is necessary to reorganize the contents focusing on cases related to speed so that students can grasp the concept of speed and use it in their everyday lives. With regard to the new curriculum and textbooks, this study proposes that students be provided the opportunity to systematically and deeply study core topics rather than exclude content that is difficult to learn and challenging to teach so that students realize the value of science and enjoy learning it.

• School Mathematics
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• v.5 no.1
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• pp.135-149
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• 2003

We present an understanding about students' conceptual model of differential equations, based on the discourse data that were collected in a differential equations course at a university in Korea. An interpretive approach is taken to analyze classroom discourse. This paper consists of three main parts. First, we completely analyze the students' use of conceptual metaphor in a university differential equations class. Secondly, we identify conceptual metaphors representing students' conceptual model of differential equations. Finally, we describe the mathematical characteristics of the conceptual metaphors identified in detail. Among other things, this paper reveals that there exists dual aspects of the students' conceptual model of differential equations. In other words, in the differential equations course observed we found that the students very often used two kinds of conceptual metaphor,“machine metaphor”and“fictive motion metaphor”, that have contrastingly different mathematical characteristics. In order to interpret the duality, we take a sociocultural perspective, and this perspective suggests and helps us to realize the significance of understanding of cognitive diversity in mathematics classroom.

• Journal of the Korean Society of Earth Science Education
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• v.16 no.2
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• pp.261-275
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• 2023

The purpose of this study was to analyze the conceptual understanding of carbon neutrality among secondary school science pre-service teachers, as well as to identify gaze patterns in visual materials. For this study, gaze tracking data of 20 pre-service secondary school science teachers were analyzed. Through this, the levels of conceptual understanding of carbon neutrality were categorized for the participants, and differences in gaze patterns were analyzed based on the degree of conceptual understanding of carbon neutrality. The research findings are as follows. First, as a result of performing modeling activities to predict carbon emissions and removals until 2100 using the concept of '2050 carbon neutrality,' 50% of the participants held a conception that carbon emissions would continue to increase. Additionally, 25% of the participants did not properly understand the causal relationship between net carbon dioxide emissions and cumulative concentrations. Second, the gaze movements of the participants regarding visual materials related to carbon neutrality were significantly influenced by the information presented in the text area, and in the case of graphs, the focus was mainly on the data area. Moreover, when visual data with the same function and category were arranged, participants showed the most interest in materials explaining concepts or visual data placed on the left side. This implies a preference for specific positions or orders. Participants with lower levels of conceptual understanding and inadequate grasp of causal relationships among elements exhibited notably reduced concentration and overall gaze flow. These findings suggest that conceptual understanding of carbon neutrality including climate change and natural disaster significantly influences interest in and engagement with visual materials.