• Journal of Educational Research in Mathematics
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• v.10 no.2
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• pp.229-246
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• 2000

The purpose of this paper is to compare and analyze the two different teaching methods of elementary mathematics in the traditional method and in the constructive view. To do so, the actual class in the constructive view has been made for about four months using a class of 45 students in the second grade of an elementary school. After the class was finished, we collected diverse data from the class, such as the responses from the children(self-evaluation, mathematics diary, observation by the investigator, daily report), class evaluation report by other teacher and so on. The results of this research are as follows: First, the traditional class reaches at the goal of learning in a unit time because the class is guided by the teacher but the class in the constructive view is a little flexible because it is contextual. Second, in the constructive process of mathematical knowledge we knew that small group activities or discussion without intervention of teacher was often ended in exhaustive argument without arriving at valid social consensus. Third, the attitude in mathematics was changed from the passive one to the self-regulated ones. Fourth, the class in the constructive view could extend not only the ability of mathematical communication but also the ability of self-directed learning of children. Fifth, it was a considerable change the role of teacher, that is, guide of instruction instead of unique specialist in the classroom. Sixth, finally, the evaluation was made after finishing a unit class in the traditional instruction but it was integrated in a class in a constructive view.

• Journal of Fashion Business
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• v.6 no.6
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• pp.43-55
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• 2002

This study intends to consider the characteristics of Tudorian costume and find out how the thoughts and cultures in those days had influences on the costume trends of low and middle class. In terms of the Tudorian costume which generated new cultural mainstreams along with blossomed civil culture, this study focuses on the characteristics and trends of costume at low and middle class, which have been little addressed in studies on western costume history or related fields, turning from the costume of upper class based on wealthy noblemen who showed off its dignity and authority along with jewelry and gorgeous ornamental craftsmanship. This study used related pictures, museum material and other literatures as its reference. It first looked into the general characteristics of western costume and considered the characteristics of costumes popularized in professionals at middle class such as apprentice, yeomen and low-class people. Professional or other middle class almost typically used to wear tunic, doublet, shirts, coat or long gown. Black was mainly used as clothes color. Similarly to upper class, silk or velvet was very often used as material. People at low class enjoyed wear costumes with simple and easy style for working. They also preferred natural color and cotton or wool as material. This study intended to find out which type of costumes people at low and middle class enjoyed wearing, rather than compare costume between such two classes.

• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.209-216
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• 2014

The purpose of this study was to explore the effect of 8 weeks after school classes of track sports on students' start motion through kinematic variables. 30 students in D National university of education participated for this study. These students divided into two groups, 17 students for experimental group and 13 students for control group. The two groups participated in general athletic class as common class, and the experimental group participated in after school class additionally. The general class taught track and jump skill for 3 hours a week, and the after school class taught only athletic running skill for 30 minutes a week. Pre and post test assessed to assess students' kinematic changes. Findings indicated that velocity and step rate were increased, and contact time, step length, displacement of center of mass were decreased in the experimental group. In the control group, early velocity, knee/hip angle velocity were increased, and contact time, step length, displacement of center of mass were decreased. In conclusion, the students who only participated in general class, could not maintain athletic skills obtained from the class. However, students who participated in both general and after school class accomplish athletic start skill. This is because Continuous learning effect helped students keep the skill and did not lose the skill. Thus, in order for students to learn specific sport skills, joining after school class with general class together is recommended.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1882-1893
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• 2016

This study intended to look into the causal relations, in which a ski class conducted at a college is linked from college students' participation motivation to satisfaction and revisit. Among others, this study intended to boost the quality of the ski class conducted at a college with focus on the difference between the influences on satisfaction and revisit according to pre/post class participation. Further, the purpose of this study is to inquire into an ultimate basic plan required for winter sports development on the basis of the deduced results, through which this study drew the conclusion as follows: First, it was found that the influence relationship between class satisfaction before/after class was established in a joy seeking factor according to ski class participation motivation. Second, the daily routine deviation factor among the sub-factors of ski class participation motivation was found to have a positive effect on revisit before/after class while friendship promotion factor, health factor and physical strength factor were found to have an influence on revisit after class.

• Journal of Engineering Education Research
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• v.25 no.6
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• pp.69-80
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• 2022

In this study, the application of flipped learning methodology to thermodynamics in mechanical engineering was examined, and how university students view flipped learning and the effects of flipped learning were analyzed. To analyze the effects of flipped learning, pre-class survey, assessment on learning in pre-class, team activities during class, and post-class survey were conducted. The analysis was also conducted on 33 students who took the thermodynamics course in mechanical engineering, and the PARTNER flipped learning model was applied to the class. The results of this study are as follows; In the preliminary survey, the students expected that the flip-learning class with team activities and teaching between team members would be helpful in improving their learning. In addition, students recognized that cooperative learning through a team was helpful for learning. The case reflecting the result of pre-learning evaluation to the subject grades showed higher pre-learning evaluation results than the case not reflecting the result of the pre-learning evaluation to the subject grades, and it was found that the pre-learning evaluation was acting as a factor to promote learning in pre-class. In post-class survey, the satisfaction with the flipped learning class was high, indicating that the effectiveness of the flipped learning class applied to the thermodynamics class was excellent.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1060-1068
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• 2011

In this paper, Current-Mode Class-D(CMCD) RF Power Amplifier(PA) is designed and implemented at 900 MHz. Conventional CMCD PA has output parallel resonator to reconstruct a fundamental frequency component of the output signal. However the resonator can be removed by connecting inverse class-F PAs because even-harmonic components can be removed by CMCD PA's push-pull structure. Using load-pull, inverse class-F PA with GaN transistors is designed, and CMCD PA with the inverse class-F PA is implemented. The CMCD PA has 64.5 % drain efficiency, 34.2 dBm output power. Comparing with the drain efficiency of a CMCD PA with parallel resonator, the CMCD with the inverse class-F technology has 13.6 % improved drain efficiency.

• The korean journal of orthodontics
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• v.20 no.1
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• pp.111-122
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• 1990

To investigate the relationship of skeletal maturity among the normal occlusion group and each malocclusion groups, the author used hand and wrist X-ray of 133 Korean 13 year old boys (normal occlusion 30, Class I malocclusion 35, Class II malocclusion 35 and Class III malocclusion 33) and assessed their skeletal maturity. In this study, fourteen skeletal maturity stages were selected from; Radius, Hamate, Pisiform, Ulnar sesamoid of the metacarpophalangeal joint of the first thumb, proximal phalanges of the first, second and third finger, middle and distal phalanx of the third finger. The difference of skeletal maturity of each malocclusion groups in relative to normal occlusion group and that of each malocclusion groups were analyzed. The findings of this study can be summerized as follows: 1. Average skeletal maturity stage of each groups were MP3cap stage in normal occlusion group, H-2 stage in Class I malocclusion group, midstage between S and H-2 stage in Class II malocclusion group, MP3cap stage in Class III malocclusion group. 2. There was no significant difference in skeletal maturity of Class I malocclusion and Class III malocclusion groups in relative to normal occlusion group. 3. There was significant retardation of skeletal maturity in Class II malocclusion group in relative to normal occlusion group. 4. There was no significant difference in skeletal maturity between Class I and Class II malocclusion groups. 5. There was no significant difference in skeletal maturity between Class I and Class III malocclusion groups. 6. There was significant retardation of skeletal maturity in Class II malocclusion group in relative to Class III malocclusion group.

• Journal of Environmental Science International
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• v.19 no.8
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• pp.1067-1076
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• 2010

How would environmental education be implemented for effectiveness today? Deep reflection on the way of teaching environment in classes to achieve effectiveness is required. If there exist differences in students' environmental perception depending on environment class pattern, its most effective way should be looked for. In environmental education, inducing the students to have advisable attitude voluntary about environment is more important than teaching them environmental knowledge. From such view, students' active participation is necessary for successful environmental classes. Students need to be set to share their principle, values, attitude about environment problems at environmental class through presentation which is important factor to make them have advisable environmental attitude. Therefore, environmental class need to be carried out student-led way. For that, a class model need to be designed which will be helpful for the students to arrange and elaborate their emitting thought about environment problems through disclosing their thoughts to share them with fellow students which will end up in their advisable environmental attitude. This study aimed to find out the effectiveness of environmental collage making class contributive to offering various environmental perception to students and grasping others' thinking about environment. Fifty-eight 10th graders at U Science High School in Ulsan metropolitan city were selected for the study that carried out from 2010 April to June by choosing total 10 environmental themes divided into environmental collage making class applied to the 30 test group students, and general environmental class applied to 28 control group students. Following are the study results. First, in students' environmental sensitivity, the students in the environmental collage making class appeared to be higher compared with them in general environmental class. Second, in students' intentional environment action, the students in the environmental collage making class appeared to be higher compared with them in general environmental class. Third, in students' satisfaction with environmental class, the students in the environmental collage making class appeared to be higher compared with them in general environmental class.

• Korean Journal of Child Studies
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• v.2
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• pp.67-82
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• 1981

The present study was intended to investigate ecological characteristics of poverty areas in Seoul from the perspectives of children's development. More specifically, the objectives of the study are to examine environmental ecology of the poverty areas and it's potential psycho-social development of children. Three poverty areas and 150 children currently living in the are as were sampled ; 70 children from middle class families and 88 from lower class respectively. Focal ecological aspects surveyed family environment, outdoor play ground and facilities, and village housing structures. Psycho-social dimension's development dealt with in the study included children's perceptions of parental child rearing practices and role taking, and children's future perception and perspectives. Data were collected through interviews and observations using structured formats. Following results were obtained from the data : 1. Children from the poverty families showed a higher tendency to have working mothers than those from middle class. 2. The rate of having single room is higher for children from middle class by two times than from lower class. 3. Children from lower class tended to have less favorable perceptions of attitudes tote and their own families than those from middle class. 4. The likelihood of showing discrepancy in vocational choice for children between parents and children is higher for children from lower class and those from middle class. 5. Children from lower class tended to allot more time in playing with peers than those from middle class. 6. The size of outdoor play ground are inadequately poor both for middle and lower class children. The inadequateness is particularly severe for the lower class children, showing that the size and facilities of playing ground available for the child from lower class is less than half compared with those of the children from middle class.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.56-64
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• 2018

In recent years, imbalanced data is one of the most important and frequent issue for quality control in industrial field. As an example, defect rate has been drastically reduced thanks to highly developed technology and quality management, so that only few defective data can be obtained from production process. Therefore, quality classification should be performed under the condition that one class (defective dataset) is even smaller than the other class (good dataset). However, traditional multi-class classification methods are not appropriate to deal with such an imbalanced dataset, since they classify data from the difference between one class and the others that can hardly be found in imbalanced datasets. Thus, one-class classification that thoroughly learns patterns of target class is more suitable for imbalanced dataset since it only focuses on data in a target class. So far, several one-class classification methods such as one-class support vector machine, neural network and decision tree there have been suggested. One-class support vector machine and neural network can guarantee good classification rate, and decision tree can provide a set of rules that can be clearly interpreted. However, the classifiers obtained from the former two methods consist of complex mathematical functions and cannot be easily understood by users. In case of decision tree, the criterion for rule generation is ambiguous. Therefore, as an alternative, a new one-class classifier using hyper-rectangles was proposed, which performs precise classification compared to other methods and generates rules clearly understood by users as well. In this paper, we suggest an approach for improving the limitations of those previous one-class classification algorithms. Specifically, the suggested approach produces more improved one-class classifier using hyper-rectangles generated by using Gaussian function. The performance of the suggested algorithm is verified by a numerical experiment, which uses several datasets in UCI machine learning repository.