• Journal of The Korean Association For Science Education
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• v.43 no.2
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• pp.111-124
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• 2023

The aim of this study was to explore science teachers' perceptions of good science teaching. To this end, the Korean Teaching Observation Protocol (KTOP), which was developed for the purpose of observing and improving science teaching, was utilized. In the first survey, teachers were asked whether they thought each item in the KTOP was important for good science teaching, the extent to which they implemented these items, and the level of difficulty in implementing them. The second survey asked teachers what they believed to be the reasons and solutions for the KTOP items that they had responded as difficult to implement. The responses obtained from 63 teachers in the first survey and 35 teachers in the second survey were categorized based on the characteristics of the responses. The categorized contents were then summarized and discussed for their features. As a result, science teachers responded that all items in KTOP, except for one, are important for good science teaching. However, it was also shown that the level of execution was low in cases where implementation was difficult. For the 13 KTOP items that were considered important but difficult to implement and showed relatively low implementation level, many respondents (69%) attributed the reason to both students and teachers. However, the most common response (60%) was that the teacher should solve those difficulties. From this, it was found that understanding and supporting teachers, as well as enhancing their competencies, are more important for good science teaching than external factors. We hope that this research findings will help to better understand the specific difficulties that science teachers face in their classes and contribute to practical efforts that aim to address these challenges.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.183-197
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• 1991

After single fraction of 2, 5, 10 Gy irradiation on submandibular gland of 40 male rats, weighing 150gm, respectively, these animal were sacrificed two hours after 0.1㎎/g bromodeoxyuridine (Sigma) peritoneal injection in 1, 3, 7, 15 hours, 1, 3, 7 days after irradiation. And excised submandibular gland were fixed in Carnoy's and Bouin's solution for 2 hours. Paraffin sections were stained with H&E, and PAS for the observation of the change of salivary gland tissue, and with Feulgen for the study of the DNA distribution, and immunohistochemically stained with anti-bromodeoxyuridine (Sanbyo Co.) for detection of DNA synthetic cells in order to study the distribution of DNA synthetic cells of salivary gland tissue and endothelium after irradiation in 5 different sites of 6 slides on X 200 high power field. The results were as followings. 1. In PAS staining 3 days after 5Gy irradiation, decreased mucine secretion of serous cells were found, and 7 days after l0Gy irradiation, decreased mucine secretion of mucous cells were found. 2. In histopathologic features, degeneration of serous cells were found in 3 days after 2 Gy irradiation and there was little change in mucous cells and excretory duct cells. 3. In Feugen staining, 3 days after 2 Gy, 5 Gy irradiation, more high percentage of DNA synthetic cells were found in intercalated duct cells, striated duct cells and excretory duct cells than in BrdU staining. 4. In immunohistochemical features, DNA synethsis of serous cells and granular convoluted tubular cells abruptly decreased in early period after irradiation and showed no recovery in 7 days after irradiation but there was an increase in DNA synthesis of intercalated duct cells, striated duct cells and excretory duct cells, which have less S-phase cells comparatively, in 7 days after 2 Gy, 5 Gy irradiation. 5. In immunohistochemical features, the DNA synthesis of endothelial cells was continuously decreased after irradiation but showed slight increase in 7 days after 2 Gy and S Gy irradiation.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.4061-4063
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• 2015

Background: To evaluate pathological features of head and neck squamous cell carcinoma (HNSCC) and to compare these pathological features in patients younger and older than 40 years. Materials and Methods: All resection specimens of HNSCC between 2010 and 2013 evaluated. Tumor characteristics - grade, location (site) cervical node status, alongwith presence or absence of extranodal extension, lymphovascular invasion, gender and age - were extracted from surgical pathology reports. Results: Among these n=19 patients (21.8%) were 40 years or younger and n=68 patients (78.2%) were above 40 years of age. The mean age was 34 (20-40 years) in the younger group and 56 (42-86) in the older group. The most common location of HNSCC in both groups was the oral cavity. The analysis of histopathological features including grade of tumor, tumor size, extranodal extension and comparison between two groups do not show any significant difference. Conclusions: There are no specific pathological characteristics of HNSCC in young patients. An interesting observation is that exposure to expected risk factors is similar in both groups, in younger patients they have less time to act and yet tumors are the same in terms of tumor size, lymph node status and lymphovascular invasion. Therefore further research is recommended to look for potentiating factors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4C
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• pp.388-396
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• 2009

This paper proposes a new fire-smoke detection method by using extracted features from camera images and pattern recognition technique. First, moving regions are detected by analyzing the frame difference between two consecutive images and generate candidate smoke regions by applying smoke color model. A smoke region generally has a few characteristics such as similar color, simple texture and upward motion. From these characteristics, we extract brightness, wavelet high frequency and motion vector as features. Also probability density functions of three features are generated using training data. Probabilistic models of smoke region are then applied to observation nodes of our proposed Dynamic Bayesian Networks (DBN) for considering time continuity. The proposed algorithm was successfully applied to various fire-smoke tasks not only forest smokes but also real-world smokes and showed better detection performance than previous method.

• Wind and Structures
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• v.31 no.3
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• pp.229-240
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• 2020

In the present work, the main features of primary vortices and the vorticity concentrations downstream of vortex bursting in crossflow plane of a delta wing with a sweep angle of Λ=70° were investigated under the variation of the sideslip angles, β. For the pre-review of flow structures, dye visualization was conducted. In connection with a qualitative observation, a quantitative flow analysis was performed by employing Particle Image Velocimetry (PIV). The sideslip angles, β were varied with four different angles, such as 0°, 4°, 12°, and 20° while angles of attack, α were altered between 25° and 35°. This study mainly focused on the instantaneous flow features sequentially located at different crossflow planes such as x/C=0.6, 0.8 and 1.0. As a summary, time-averaged and instantaneous non-uniformity of turbulent flow structures are altered considerably resulting in non-homogeneous delta wing surface loading as a function of the sideslip angle. The vortex bursting location on the windward side of the delta wing advances towards the leading-edge point of the delta wing. The trajectory of the primary vortex on the leeward side slides towards sideways along the span of the delta wing. Besides, the uniformity of the lift coefficient, C_L over the delta wing plane was severely affected due to unbalanced distribution of buffet loading over the same plane caused by the variation of the sideslip angle, β. Consequently, dissimilarities of the leading-edge vortices result in deterioration of the mean value of the lift coefficient, C_L.

• Journal of Gifted/Talented Education
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• v.14 no.4
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• pp.15-45
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• 2004

The purpose of this study is to find out the effect of science journal writings on the cognitive and affective features of the science gifted students. In this research, the tasks of on-line science journal writings were assigned for 6 months and the subjects in this study were 21 students of Chemistry Division of the Center for Science Gifted Education, Seoul National University. Consequently in science journals, science concepts are found in various aspects according to the writing formats, and psychological and behavioral characteristics of the science-gifted are revealed in positive or negative aspects. In cognitive prospect, science journal writing equips students with better understanding about science concepts and scientific research. In affective prospect, science journal writing help students improve observation and attitude toward science as wren as writing skills. Accordingly, science journal writing has positive effect on cognitive and affective characteristics of the science-gifted. In conclusion, acknowledged by most of science-gifted students as both beneficial and appropriate in their education program, science journal writing should be emphasized in education for science-gifted students.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.360-364
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• 2021

Objectives: The purpose of this study was to evaluate the clinical and radiographic characteristics of idiopathic bone cavity (IBC) to determine the effect of surgical intervention on the process of healing. Materials and Methods: All cases diagnosed with IBC during the period of 2011 to 2020 at our Department of Oral and Maxillofacial Surgery were searched. Ninety cases were retrieved. The features evaluated were sex, age, contour of the lesion, number of teeth involved, site, history of trauma, and postoperative healing pattern. The significance of differences was assessed by Mann-Whitney U test and chi-square test. Results: The female:male ratio showed no predilection toward either sex (0.9:0.8). The mean age of the collected sample was 22.05±14.38 years, and the age ranged from 10 to 58 years. All cases presented in the mandible and showed well-circumscribed radiolucency. Margins were either scalloped or round in shape, and the size varied from one tooth to six teeth involvement. Seventy cases involved three or fewer roots. Three cases showed bilateral lesion. Four cases had a history of trauma at the area of the lesion. Fifty-one cases were followed for six months after surgery, and all showed increased bone density at the lesion. Conclusion: There is no definitive radiological or clinical feature of IBC. Considering the diversity of clinical and radiological features, such a diagnosis relies primarily on surgical findings of an empty bone cavity with no epithelial lining. Our data suggest that surgical intervention be the first choice of treatment as opposed to observation.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.2
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• pp.135-144
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• 2021

Purpose: Although ultrasonography is the gold standard of diagnosing intussusception, plain abdomen radiograph (AXR) is often used to make differential diagnosis for pediatric patients with abdominal pain. In intussusception patients, we aimed to analyze the AXR and clinical data to determine the characteristics of early AXR findings associated with diagnosis of intussusception and recurrence after reduction. Methods: Between January 2011 and June 2018, 446 patients diagnosed with intussusception based on International Classification of Diseases-10 code of K56.1 were admitted. We retrospectively reviewed medical records of 398 patients who received air reduction; 51 of them have recurred after initial reduction. We evaluated six AXR features including absent ascending colon gas, absent transverse colon gas, target sign, meniscus sign, mass, and ileus. Clinical data and AXR features were compared between single episode and recurrence groups. Results: Two groups did not show significant differences regarding clinical data. Mean time to recurrence from air reduction was 3.4±3.2 days. Absent ascending colon gas (63.9%) was the most common feature in intussusception, followed by mass (29.1%). All of six AXR features were observed more frequently in the recurrence group. Absent transverse colon gas was the most closely associated AXR finding for recurrence (odds ratio, 2.964; 95% confidence interval, 1.327-6.618; p=0.008). Conclusion: In our study, absence of ascending colon gas was the most frequently seen AXR factor in intussusception patients. Extended and careful observation after reduction may be beneficial if such finding on AXR is found in intussusception patients.

• Journal of The Korean Association For Science Education
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• v.33 no.4
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• pp.778-793
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• 2013

The purpose of this study is to analyze observation characteristics through eye movement according to cognitive styles. To do this, we developed observation tasks that show the differences between wholistic cognitive style group and analytic cognitive style group, measured eye movement of university students with different cognitive styles after being given an observation task. The difference between two cognitive style groups is confirmed by analysing gathered statistics and visualization data. The findings of this study are as follows: First, to compare fixation time and frequency, we compared the average value of total time used in the observation task by the wholistic cognitive style group and analytic cognitive style group. The numbers of Fixation (total) and number of Fixations (30s), is based on the fact that the wholistic cognitive style group has more numbers of fixation (Total) and number of fixations (30s) means the wholistic cognitive style group can observe more points or overall features than the analytic cognitive style group, in contrast, the analytic cognitive style group tend to focus on a particular detail, and observe less numbers of points. Second, to compare observation object and area by cognitive style, the outcome of analysing visualization data shows that wholistic cognitive style group observes the surrounding environment of spider and web on a wider area, on the other hand, the analytic cognitive style group observes by focusing on the spider itself. Through the result of this study, there are differences in observation time, frequency, object, area, and ratio from the two cognitive styles. It also shows the reason why each student has varied outcome, from the difference of information following their cognitive styles, and the result of this study helps to figure out and give direction as to what observation fulfillment is more suitable for each student.

• Conservation Science in Museum
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• v.20
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• pp.31-48
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• 2018

The Geumganasa Temple site two Ridege-end tiles at the Buyeo National Museum(The Buyeo2150-1 and 2150-2, hereinafter referred to as 2150-1 and 2150-2) were excavated the Geumgangsa Temple site. They provide important materials for investigating the shapes and production techniques of the ridge-end tiles of the time since their lower portions remain relatively intact. This study is intended to examine whether the two ridge-end tiles were identical. Conservation treatment, including removal of foreign substances, was conducted in preparation for observation with the naked eye to compare the formal features and production techniques of the two examples. The study revealed that these ridge-end tiles shared formal features such as surface color, clay composition, shape, size, and decoration; however, they differed in terms of production technique. The 2150-1 tile was made by assembling a separately-made body and wing and has no hole through the back, while the 2150-2 tile had its body and wing made as a single unit using long clay plates and features circular holes in the back. It was revealed that one portion of the body of both tiles was intentionally tilted during the production process.