• Communications of Mathematical Education
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• v.37 no.2
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• pp.299-327
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• 2023

In this study, we tried to find out the level of inductive reasoning ability and the aspects of visualization components shown in students in the class using exploratory software for the 'congruence and symmetry' unit in the second semester of the 5th grade of elementary school. To this end, classes using GeoGebra, one of the exploratory software, were conducted for a total of 19 students in one class of fifth graders in elementary school, and the results of the students' activities were analyzed. As a result of this study, the level of inductive reasoning ability of students remained at a similar level or developed, and it was shown that students inferred new properties of shapes using various functions of software inductively. In addition, in terms of visualization, students were able to quickly and easily draw shapes that met the conditions, and unlike the paper-and-pencil environment, using the 'measurement' and 'symmetry' functions, they transformed and manipulated complex yet precisely congruent and symmetrical external representations. Based on these analysis results, implications for the use of exploratory software in the area of figures were derived.

• Korean Journal of Optics and Photonics
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• v.34 no.5
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• pp.185-191
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• 2023

We report the results of evaluating the hardness, flexibility, and adhesion between the protective layer and the stealth sheet after applying a protective layer to improve the practicality of the flexible stealth sheet. The result of the ISO 15184 pencil hardness test showed that the hardness increased from HB to 3H by three grades when a protective layer was applied. The flexibility evaluation was conducted by bending the material against cylinders of certain diameters and observing whether cracks occurred according to the ASTM D522 test method. The result showed that the minimum diameter was 0.125 inches. The adhesion was evaluated by using the ASTM D3359 test method, attaching and peeling off an adhesive strip to the protective layer and determining the proportion of the protective layer peeling off. The result was 5B, which is better than the military adhesion limit of 4B.

• Journal of The Korean Association For Science Education
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• v.26 no.1
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• pp.68-87
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• 2006

The aim of this study was to understand the components that influence the mental models of preservice elementary teachers on the astronomical phenomena of seasons of the year and lunar phases of the month. For this, participants were selected from a university of education. Data was collected from a paper-pencil test and individual interviews with the participants. The results of this study showed that the preservice teachers had apparent synthetic mental models, and that the 'Distance Theory' and 'Occlusion Theory' had the greatest effect on their mental models. Furthermore, it was found that preservice elementary teachers' initial mental models of 'astronomical phenomenon' had their origin in personal belief sets (specific theory) related to 'astronomical phenomenon'. It was on these belief sets that they interpreted their observations and cultural information with the constraints of a naive framework of physics. The structures and possible sources for overcoming these synthetic mental models were also discussed in this paper. Lastly, implications for preservice elementary teacher education were presented.

• Journal of The Korean Association For Science Education
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• v.23 no.3
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• pp.265-275
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• 2003

The purpose of this study is to investigate the differences of science achievement between female- and male students in different assessment types, expecting the reconsideration of their scientific ability. to accomplish this purpose, the school science achievement score of 1,487 female- and male students in 2000 were analyzed from the perspectives of assessment methods and gender differences, achievement level and gender differences, and gender characteristics in correlation between each assessment type and total science score. The science achievement score in this study includes mi-term and final paper-and-pencil test in two semesters and performance assessment. The results are as follows. First, in the total science achievement score, whereas female students achieved significantly better than male counterparts in the 7th grade, there was no significant difference between two genders in the 8th and 9th grades. Second, as for the close-ended items, all students, regardless of their gender and grade, showed no significant difference. As for the open-ended items, whereas female students achieved significantly better than male counterparts in the 7th grade, there was no significant difference between gender in the 8th and 9th grades. As for the performance assessment, all female students, regardless of their achievement level, achieved significant better than male counterparts, which is very noteworthy. Third, in the uppermost achievement level, there was no significant difference not only in close- and open ended items but also in performance assessment. Fourth, male students' correlation between performance assessment and total science score was relatively higher than female students'. The result of this study, that female students did significantly better than male students in performance assessment, is interesting in that performance assessment is widely accepted as more reliable and valid method in measuring students' various ability than traditional paper-and-pencil test.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.1
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• pp.23-30
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• 2012

Purpose: There was a problem with using MU verification programs for the reasons that there were errors of MU when using MU verification programs based on Pencil Beam Convolution (PBC) Algorithm with radiation treatment plans around lung using Analytical Anisotropic Algorithm (AAA). On this study, we studied the methods that can verify the calculated treatment plans using AAA. Materials and Methods: Using Eclipse treatment planning system (Version 8.9, Varian, USA), for each 57 fields of 7 cases of Lung Stereotactic Body Radiation Therapy (SBRT), we have calculated using PBC and AAA with dose calculation algorithm. By developing MU of established plans, we compared and analyzed with MU of manual calculation programs. We have analyzed relationship between errors and 4 variables such as field size, lung path distance of radiation, Tumor path distance of radiation, effective depth that can affect on errors created from PBC algorithm and AAA using commonly used programs. Results: Errors of PBC algorithm have showned $0.2{\pm}1.0%$ and errors of AAA have showned $3.5{\pm}2.8%$. Moreover, as a result of analyzing 4 variables that can affect on errors, relationship in errors between lung path distance and MU, connection coefficient 0.648 (P=0.000) has been increased and we could calculate MU correction factor that is A.E=L.P 0.00903+0.02048 and as a result of replying for manual calculation program, errors of $3.5{\pm}2.8%$ before the application has been decreased within $0.4{\pm}2.0%$. Conclusion: On this study, we have learned that errors from manual calculation program have been increased as lung path distance of radiation increases and we could verified MU of AAA with a simple method that is called MU correction factor.

• Progress in Medical Physics
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• v.24 no.1
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• pp.35-40
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• 2013

Recently, the uses of Multi-Detector Computed Tomography (MDCT) for radiation treatment simulation and planning which is used for intensity modulated radiation therapy with high technique are increasing. Because of the increasing uses of MDCT, additional doses are also increasing. The objective of this study is to evaluate the absorbed dose of body and skin undergoing in MDCT scans. In this study, the exposed dose at the surface and the center of the cylindrical water phantom was measured using an pencil ionization chamber, 30 cc ionization chamber and TL Powder. The results of MDCT were 31.84 mGy, 33.58 mGy and 32.73 mGy respectively. The absorbed dose at the surface showed that the TL reading value was 33.92 mGy from MDCT. These results showed that the surface dose was about 3.5% from the MDCT exposure higher than a dose which is located at the center of the phantom. These results mean that the total exposed dose undergoing MDCT 4 times (diagnostic, radiation therapy planning, follow-up et al.), is about 14 cGy, and have to be considered significantly to reduce the exposed dose from CT scan.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.11-19
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• 2014

Purpose : To derive the most appropriate factors by considering the effects of the major factors when applied to the optimization algorithm, thereby aiding the effective designing of a ideal treatment plan. Materials and Methods : The eclipse treatment planning system(Eclipse 10.0, Varian, USA) was used in this study. The PBC (Pencil Beam Convolution) algorithm was used for dose calculation, and the DVO (Dose Volume Optimizer 10.0.28) Optimization algorithm was used for intensity modulated radiation therapy. The experimental group consists of patients receiving intensity modulated radiation therapy for the head and neck cancer and dose prescription to two planned target volume was 2.2 Gy and 2.0 Gy simultaneously. Treatment plan was done with inverse dose calculation methods utilizing 6 MV beam and 7 fields. The optimal algorithm parameter of the established plan was selected based on volume dose-priority(Constrain), dose fluence smooth value and the impact of the treatment plan was analyzed according to the variation of each factors. Volume dose-priority determines the reference conditions and the optimization process was carried out under the condition using same ratio, but different absolute values. We evaluated the surrounding normal organs of treatment volume according to the changing conditions of the absolute values of the volume dose-priority. Dose fluence smooth value was applied by simply changing the reference conditions (absolute value) and by changing the related volume dose-priority. The treatment plan was evaluated using Conformal Index, Paddick's Conformal Index, Homogeneity Index and the average dose of each organs. Results : When the volume dose-priority values were directly proportioned by changing the absolute values, the CI values were found to be different. However PCI was $1.299{\pm}0.006$ and HI was $1.095{\pm}0.004$ while D5%/D95% was $1.090{\pm}1.011$. The impact on the prescribed dose were similar. The average dose of parotid gland decreased to 67.4, 50.3, 51.2, 47.1 Gy when the absolute values of the volume dose-priority increased by 40,60,70,90. When the dose smooth strength from each treatment plan was increased, PCI value increased to $1.338{\pm}0.006$. Conclusion : The optimization algorithm was more influenced by the ratio of each condition than the absolute value of volume dose-priority. If the same ratio was maintained, similar treatment plan was established even if the absolute values were different. Volume dose-priority of the treatment volume should be more than 50% of the normal organ volume dose-priority in order to achieve a successful treatment plan. Dose fluence smooth value should increase or decrease proportional to the volume dose-priority. Volume dose-priority is not enough to satisfy the conditions when the absolute value are applied solely.

• The korean journal of orthodontics
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• v.27 no.4 s.63
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• pp.549-557
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• 1997

This study was designed to investigate the attrition pattern in Angle Class III malocclusion with facial asymmetry. The sample consisted of three groups, the 20 subjects of normal occlusion group(Group I), the 12 subjects of class III malocclusion without facial asymmetry group(Group II) and 17 subjects of Class III malocclusion with facial asymmetry group(Group III). Attrition areas from canine to second molar on both sides in upper and lower arch, totally twenty, was marked by pencil and mesured by computer system(INTERGRAPH CO. USA) 2 times and the average value was used for date processing. Attrition areas from canine to second molar on both sides in upper and lower arch, totally twenty, was marked by pencil and mesured by computer system(INTERGRAPH CO. USA) 2 times and the average value was used for date Processing. All attrition areas were measured 2 times and the average value was used for data processing The data were statistically analyzed by SAS program. The results of this study were as follows. 1. Total attrition area in Group I was larger than in Group II and III. 2. There was no significant difference in attrition area between right and left side in each group, but attrition area in Group III was larger than in Group I and II. 3. In Group I, Maxillary attrition area was larger than mandibular attrition area, but in Group ll and III, there was no significant difference in attrition area between maxilla and mandible. 4. In Group III, the attrition area of deviated side was target than undeviated side 5. There was no significant difference in attrition area between chewing side and non-chewing side in each group. 6. The total attrition area was unaffected by gender.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.43-49
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• 2019

Purpose : We apply the Layered Rescanning PBS designed to complement the Pencil Beam Scanning(PBS), which is vulnerable to moving organs with the Moving Phantom, and compare the homogeneity with the single scan PBS. Methods and materials: Matrix X (IBA, Belgium) and Moving Phantom (standard imaging, USA) were used. A dose of 200 cGy was measured in the AP direction on a hypothetical tumor $10{\times}10{\times}5cm$. The plan type was planned as 4 kinds of sinlge scan PBS, rescan number 4, 8, 12 times. Were measured three times for each types. During the measurement, the respiratory cycle of the Moving Phantom was generally set to 4 seconds per cycle, and the movement radius in the S-I direction was set to 2 cm. In addition, beam on time was measured. Results : The mean values of $D_{max}$ in the PTV were $246.47{\pm}18.8cGy$, $223.43{\pm}8.92cGy$, and $222.47{\pm}7.7cGy$, $213.9{\pm}6.11cGy$ and the mean values of $D_{min}$ were $165.53{\pm}4.32cGy$, $173.13{\pm}11.94cGy$, $184.13{\pm}8.04cGy$, $182.67{\pm}4.38cGy$ and the mean values of $D_{mean}$ $192.77{\pm}6.98cGy$, $196.7{\pm}4.01cGy$, $198.17{\pm}4.96cGy$, $195.77{\pm}3.15cGy$ respectively. As the number of rescanning increased, the Homogeneity Index converged to 1. The beam on time was measured as 2:15, 3:15, 4:30, 5:37 on average. In the measurement process, in the low dose layer of the MU, the problem was found that it was not rescanned as many times as the set number of rescan. Conclusions : In the treatment of tumors with long-term movements, the application of layered rescanning PBS showed a more uniform dose distribution than single scan PBS. And as the number of rescan increase, the distribution of homogeneity is uniform. Compared with single scan plan and 12 rescan plan, HI value was improved by 0.32. Further studies are expected to be applicable to patients who can not be treated with respiratory synchronous radiation therapy.

• Korean Journal of Social Welfare
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• v.60 no.2
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• pp.5-28
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• 2008

This study tried to develop an test tool of social workers' ethical sensitivity(SWEST) on base of realization about the importance of ethical sensitivity of social worker who are required more ethicalities than the other professionals. Nevertheless, there has been no tool that can measure ethical sensitivity of social workers in our country up to now. Through analysis of existing ethical sensitivity tests in other professions, a paper and pencil method about unstructured question with cases including ethical issues and structured scoring system was chosen as an appropriate method for the SWEST. This study progressed in order : 1st collecting cases, 2nd composing cases, 3rd consulting cases, 4th pilot study, 5th making scoring standards, 6th determining case examples and scoring standards. With the result, the tool consists of 3 case examples with ethical issues : 1) self-determination and confidentiality, 2) equality and double relationship, 3) informed consent and conflict interest. And ethical sensitivities of social work major students and social workers were measured with the SWEST, to see practical utility of this test. The agreement degrees between two independent raters were above 90%. And respondent's ethical sensitivity displayed the most definite difference according to taking or not taking a course 'Social work values and ethics'. Through these results, it can be drawn that the SWEST is reliable and valid to test relevant differences in Korean social workers' ethical sensitivity. The SWEST is expected to activate studying, educating, and practicing ethics in social work.