• Journal of the Korean earth science society
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• v.35 no.2
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• pp.147-158
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• 2014

The purpose of this study was to explore changes of elementary science class in student oriented group inquiry activities using a Science Writing Heuristic (SWH) template that enhance scaffolding of inquiry. The changes focused on students' written reports and perceptions of their learning environment as well as discourse patterns. One fourth-grade class of 29 students participated in this study, and a developed work sheet of science writing was utilized to scaffold student's inquiry activities. Four units in the first-semester text book for fourth grade of the-, 2007 Educational Curriculum Revision were chosen for scaffolding inquiry, and sixteen lessons of instruction were all videotaped. For investigating students' written reports, a framework based on the aspects of science inquiry by Millar (2010) was used to evaluate the coherence between student inquiry activities and their claims. Secondly, a regular fourth-grade class was selected as the control group and was compared with the experiment group using the pre- and post-test of the survey on the perception of science class and science. Lastly, students' discourse patterns of the beginning science lesson were compared with those of the closing lesson. We found that the coherence in the last class increased significantly in students' written reports compared to the first one. Findings also indicated that students' perceptions on their learning environment moved toward student-centered. Based on our discourse patterns analysis, the last class was more student-centered from being teacher-centered than the first one.

• Journal of KIISE:Software and Applications
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• v.32 no.8
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• pp.781-788
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• 2005

LDA (Linear Discriminant Analysis) is a data discrimination technique that seeks transformation to maximize the ratio of the between-class scatter and the within-class scatter While it has been successfully applied to several applications, it has two limitations, both concerning the underfitting problem. First, it fails to discriminate data with complex distributions since all data in each class are assumed to be distributed in the Gaussian manner; and second, it can lose class-wise information, since it produces only one transformation over the entire range of classes. We propose three extensions of LDA to overcome the above problems. The first extension overcomes the first problem by modeling the within-class scatter using a PCA mixture model that can represent more complex distribution. The second extension overcomes the second problem by taking different transformation for each class in order to provide class-wise features. The third extension combines these two modifications by representing each class in terms of the PCA mixture model and taking different transformation for each mixture component. It is shown that all our proposed extensions of LDA outperform LDA concerning classification errors for handwritten digit recognition and alphabet recognition.

• Journal of Korean Home Economics Education Association
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• v.13 no.3
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• pp.147-160
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• 2001

The purpose of this study is to suggest one of teaching methods through developing a new guideline of the teaching-learning applied the Problem-Based Learning which is derived from the Constructionism. And then we apply this guideline to the class of Home Economics. especially the unit of the Consumption life for investigating the effect of this method in the aspect of improving man-power development as a consumer The results of this study are summarized as follows : First. the class applied a new method of Problem-Based Learning turn out to be more improved in the aspect of consumer consciousness than the untested class going through explanation-based teaching(P< .01). This is, the former result more positive than the latter because the former could be given chances to handle faced problems in class. Second there is no significant difference between the tested class and the untested class in the aspect of consumer skill. This is the fact that the research was conducted in a short Period of time and that the researcher failed to show the suitable stimulation or materials. even though the researcher was well aware of what Problem-Based Learning is. Third students\` evaluation after the test indicates that the tested class not only increase interest in home economics but also help them to take an active Part in class as the main of the class. and that the learning atmosphere is improved and that the effect of learning was also enhanced. Although the aspect of consumer skill is not statistically significant. the result show that adolescents try to Practice their learning from the class in their life.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.6
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• pp.56-61
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• 2011

A class-D audio amplifier is widely used in coil speaker. This paper presented the technique for applying a class-D audio amplifier to the ceramic flat speaker. This technique can be achieved by employing a matching transmitter in order to replace class-G amplifier that is drven by voltage level to class-D amplifier employing power driving method. Consequently, the presented technique can improve the efficiency by making the voltage driving level a litter larger. We evaluate the sound-level efficiency using the various mediums such as wood, plastic, and paper. From the simulation results, the proposed technique employing a class-D audio amplifier rather than a class-G one showed a 10% improvement. The proposed system can be applicable for the mobile appliances as an external slim speaker.

• Journal of Yeungnam Medical Science
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• v.18 no.2
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• pp.208-214
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• 2001

Background: When we make treatment plan of class III malocclusion children, it is difficult to determine whether we treat it with orthognathic surgery or without orthognathic surgery. To determine that, we must consider many factors, such as cephalometric analysis, growth pattern, family history, and skeletal age. A Harvold cephalometric analysis is useful in determining the amount of discrepancy by comparing the maxillary unit length with mandibular, unit length. We tried this study to help the decision of treatment planning in class ill malocclusion children by comparison in class III malocclusion and normal occlusion children using a Harvold analysis. Materials and Methods: The materials for this study consisted of 20 class III malocclusion children. Cephalometric tracing and measurements were performed by one investigator. The control group consisted of 18 normal occlusion children and lateral cephalograms were obtained from 8.5 to 14.5 years old children biannually. The relationships between class III malocclusion group and normal occlusion group were evaluated statistically. Results: The lower anterior facial heights between two groups were not significantly different, although the lower anterior facial heights of class III malocclusion group was higher than those of normal occlusion group in all age groups. The Maxillary-mandibular unit length differences of class III malocclusion group were significantly higher than those of normal occlusion group(p<0.05). Conclusion: A Harvold analysis was useful to make treatment planning for class III malocclusion children.

• Journal of Korean Neurosurgical Society
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• v.30 no.11
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• pp.1300-1307
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• 2001

Purposes : This study reports the possible causes of seizure recurrence in patients underwent previous epilepsy surgery, and surgical strategy for resection of the additional epileptogenic zone locating at the distant area to the site of first resection. Methods : A total of 10 patients with previous surgery due to intractable epilepsy were studied. Five of these underwent standard temporal lobectomy, four extratemporal resection, and one corticoamygdalectomy. Seizure outcome of these were class III-IV. Evaluation methods for reoperation included MRI, 3D-surface rendering of MRI, PET, prologned video-EEG recording with surface electrodes and subdural grid electrodes. Additional resection was done in the frontal lobe in two, in the temporal lobe in three, in the parietal lobe in two, and in the supplementary sensori-motor area in two. Tumor in the superior frontal gyrus in the left hemisphere was removed in one patient. Extent of resection was decided based on the results of ictal subdural grid EEGs and MRI findings. Awake anesthesia and electrocortical stimulation were performed in the two patients for defining the eloquent area. Results : Histopathologic findings revealed extratemporal cortical dysplasia in six, hippocampal sclerosis and cortical dysplasia of the temporal neocortex in one, neuronal gliosis in two, and meningioma in one. Previous pathology of the five patients with cortical dysplasia in the second operation was hippocampal sclerosis plus cortical dysplasia of the temporal neocortex. After reoperation, seizure outcomes were class I in six, class II in three, class III in one at the mean follow-up period of 17.5 months. Characteristically, patients in class II-III after reoperation showed histopathologic findings of hippocampal sclerosis plus temporal neocortical cortical dysplasia plus extratemporal cortical dysplasia. Conclusions : Seizure recurrence after epilepsy surgery was related with the presence of an additional epileptogenic zone distant to the site of first operation, and the majority of the histopathology of the surgical specimens was cortical dysplasia. In particular, hippocampal sclerosis plus temporal neocortical cortical dysplasia was highly related with seizure recurrence in patients with previous operation. In these patients, multimodal evaluation methods were necessary in defining the additional epileptogenic zone.

• Journal of the Korean housing association
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• v.26 no.2
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• pp.89-101
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• 2015

The purpose of this study is to explore the housing pathways of middle-class married women toward owning a first home. In doing so, an in-depth interview as a qualitative method was conducted, life history was utilized to track down the path to first-home owning, and all the interviews were transcribed for analysis. The research participants were well-educated middle-class full-time housewives owning a home. The findings indicated that family formation through marriage and child birth was a primary driving force to buy a home. It was shown that owning a home was perceived not just as a stepping stone for building both family wealth and social capital but as one of the most important pillars to reinforcing traditional family values. In spite of some intergenerational distinctions on the path toward home owning, commonalities across generations included that home owning was considered to be a social icon for middle-class, it became almost impossible for younger generations without parental support which stimulated the intergenerational transfer of wealth, and it was greatly determined by both family income (affordability) and home finance options(borrowing capacity). This research implies that the changing social landscape transforms the value on homeownership and could undermine the socioeconomic strengths of home owning. Nonetheless, it's of importance to strategically assist first homebuyers who are likely to be a member of middle-class.

• The Journal of the Korean dental association
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• v.50 no.2
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• pp.64-71
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• 2012

Recently, the presurgical orthodontic duration tends to be shortened by virtue of the advancement of surgical and orthodontic techniques in class III orthognathic surgery cases. But the predictability of the surgical results should be secured by removing several uncertain factors in presurgical orthodontic treatment. The purpose of this study is to investigate the influence of immediate postsurgical occlusal stability on postsurgical mandibular change. The study includes 40 patients who underwent orthognathic surgery to correct skeletal class III malocclusion. The patients were divided into two groups based on the numbers of occlusal contact in surgical setup occlusion: group 1 (stable surgical occlusion, n=24) and group 2(unstable surgical occlusion, n=16). Changes of horizontal and vertical mandibular measurements during postsurgical follow up period(from 1 week postsurgery to 12month after debonding) were compared to examine the differences between two groups. The stability of surgical occlusion is one of the factors influencing postsurgical mandibular changes in class III malocclusion. The various class III malocclusion cases have specific prerequisites for the orthognathic surgery according to the skeletal patterns. The prerequisites should be obtained by minimum presurgical orthodontics to increase the predictability of the surgical results.

• The Journal of the Acoustical Society of Korea
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• v.27 no.2E
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• pp.57-63
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• 2008

Stethoscopic auscultation is still one of the primary tools for the diagnosis of heart diseases due to its easy accessibility and relatively low cost. It is, however, a difficult skill to acquire. Many research efforts have been done on the automatic classification of heart sound signals to support clinicians in heart sound diagnosis. Recently, hidden Markov models (HMMs) have been used quite successfully in the automatic classification of the heart sound signal. However, in the classification using HMMs, there are so many heart sound signal types that it is not reasonable to assign a new class to each of them. In this paper, rather than constructing an HMM for each signal type, we propose to build an HMM for a set of acoustically-similar signal types. To define the classes, we use the KL (Kullback-Leibler) distance between different signal types to determine if they should belong to the same class. From the classification experiments on the heart sound data consisting of 25 different types of signals, the proposed method proved to be quite efficient in determining the optimal set of classes. Also we found that the class determination approach produced better results than the heuristic class assignment method.

• Journal of Korean Elementary Science Education
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• v.21 no.1
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• pp.127-134
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• 2002

Although the reward based on group accomplishment in cooperative learning has a merit to emphasize interdependency, it may have some undesirable side effects such as free rider effect and sucker effect. For the purpose of reducing these side effects, this study examined how the adjustment of the reward structure affected the scholastic achievement, the perception of learning environments, and the attitude toward science class by adding individual reward to group reward. We selected 2 classes of sixth grade in an elementary school, and taught on oxygen and carbon dioxide for 13 class hours in cooperative learning strategies. Group reward was applied to one class, and both group and individual rewards were applied to the other class. Analysis of the results indicated that the achievement scores of the students under the group and individual rewards were significantly higher than those under the group reward. In addition, they had more difficulty in science class and felt less satisfied. The upper level students under the group and individual rewards were also found to exhibit more competition. Educational implications were discussed.