• Korean Journal of Optics and Photonics
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• v.29 no.1
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• pp.7-12
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• 2018

In the field of machine vision, a variety of lenses are used to inspect a product for defects. Only part of the appearance of an object can be photographed with a general lens. Optical components such as mirrors, multiple lenses and cameras are required to inspect the entire exterior. This increases the size of the optical system, and has the disadvantage of high cost. In this paper, we design a hypercentric lens, which can photograph the top and side of an object, and various sizes of objects while maintaining the image size. Also, the validity of the design is verified through the performance analysis of the product.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.411-416
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• 2019

In this paper, we describe a measurement system based on vision for detecting the rotation axis of dimpled golf ball. Some golf balls have wrong rotation axis owing to bad production and scratch. A flying golf ball makes sliced or curved motion mainly to owing the wrong rotation axis of golf ball. Dimples of golf ball make a golf ball higher and more straight flying. When we hit a golf ball by driver or iron club, the dimpled ball flies straight and rotates as well. While the ball flying, the rotating axis of the ball convergence. And this makes the ball motion curved. If we hit a golf ball in direction of the rotation axis, the flying ball makes straight motion. In this paper, we develop a control system to detect convergence axis and time of flying golf ball based on vision system. To show validity of the developed system, We experimented several case for dimpled golf balls.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.2
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• pp.114-120
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• 2017

There have been many studies to develop methods for predicting diabetes and to prevent diabetes. The validity of glycated hemoglobin (HbA1c), one of the commonly known tools in predicting diabetes, has been verified by many previous studies. In this study, we examined the cutoff value of HbA1c for diabetes and impaired fasting glucose (IFG). Based on this study, we proposed a proper clinical guideline and evaluated the validation of the guideline. Excluding those without blood glucose and HbA1c data, we used the data of 5,161 subjects (2,281 men and 2,880 women) over the age of 20 years from the 2015 Korean National Health and Nutrition Examination Survey. The correlation efficient of fasting plasma glucose (FPG) and HbA1c was 0.79, indicating a strong relationship. Howeve, the correlation efficient of FPG and HbA1c was low, showing 0.27 in non-diabetes, 0.39 in IFG, and 0.66 in diabetes, showing a strong relationship. The cutoff value of HbA1c for predicting diabetes using ROC curve was 6.05% (sensitivity 84.6%, and specificity 92.0%), and AUC was 0.941 (0.937 in men, and 0.946 in women). The cutoff value of HbA1c for predicting IFG using ROC curve was 5.55% (sensitivity 64.5%, and specificity 70.0%), and AUC was 0.733 (0.708 in men, and 0.764 in women). Therefore, it may not be appropriate to apply the guidelines for diagnosing IFG since sensitivity and specificity were below 70%. For future studies retarding the cutoff value of HbA1c in predicting IFG, high sensitivity and specificity are expected if we segment the reference range of IFG.

• Pediatric Infection and Vaccine
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• v.8 no.2
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• pp.150-159
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• 2001

Purpose : We need to reconsider booster vaccination schedule of Japanese encephalitis vaccination. To do that we evaluate the long-term immunogenicity and the incidence of adverse events with inactivated mouse brain derived Nakayama Japanese encephalitis vaccine. Methods : We tested neutalizing antibody for 311 elementary school students by plaque reduction neutralizing test(PRNT) at USAMC-AFRIMS(United States Armed Forces Research Institute of Medical Science/Department of Virology). We evaluated vaccine related adverse events by spontaneous reporting prospectively among 15,487 vaccinees who were vaccinated at public health center and 2,277 elementary school students who were immunized previously by a questionnaire and school health record. Results : According to the time interval from the last booster injection of 311 children, PRNT antibody titers gradually decreased as the interval increased; 239 mIU/mL, 188 mIU/mL, 134 mIU/mL, 49 mIU/mL each at 6, 18, 30, 42 months after the last booster injection. The seropositivity rates were 98%, 99%, 95.6%, 71.4% each at 6, 18, 30, 42 months after the last booster injection. There were 21(0.13%) cases with systemic reactions among 15,487 vaccinees who had visited the hospital by prospective passive reporting system at public health center. According to the questionnaires and school health records in elementary school students, local induration and pain were 17.4% and 14.8%, respectively. Systemic reactions including fever, vomiting, rash were reported in few cases. Conclusion : Biannual booster vaccination that has been recommended so far should not be necessary. Surveillance for adverse events with inactivated mouse brain derived Nakayama vaccine should be strengthened to better assess the number of cases and reactions associated with immunization.

• Journal of Nutrition and Health
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• v.42 no.5
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• pp.486-495
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• 2009

The purpose of this study was to analyze the performance evaluation index for a salt reduction project. Questionnaires were developed in order to investigate salt reduction programs nationwide. The evaluation index and programs were analyzed through the case study of a salt reduction program in public health centers. The validity of the salt reduction program's evaluation index was determined based on study of the Delphi survey and on discussion with nutrition and health care professionals. The Delphi survey showed that daily salt intake was the most valid nutritional evaluation index. Stroke mortality and stomach cancer mortality were good health care evaluation indexes. The method for measuring salt intake that had the greatest validity was a 24-hour urine collection. However, 24-hour urine collection had the lowest score for ease of performance. The combined scores of validity and ease of performance showed that the survey method for dietary attitude and dietary behavior, dietary frequency analysis (DFQ 15), and a salty taste assessment, in that order, were proper methods. The high reliability of the salty taste assessment indicated that the percentage of the population that exhibits proper salt intake (2,000 mg sodium or less daily) and the percentage of the population that consumes low-salt diets as nutritional evaluation indexes also will be helpful to evaluate performance of salt reduction programs.

• Journal of The Korean Association For Science Education
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• v.34 no.8
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• pp.703-718
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• 2014

This study sought to investigate learning progressions for astronomical systems which synthesized the motion and structure of Earth, Earth-Moon system, solar system, and the universe. For this purpose we developed ordered multiple-choice items, applied them to elementary and middle school students, and provided validity evidence based on the consequence of assessment for interpretation of learning progressions. The study was conducted according to construct modeling approach. The results showed that the OMCs were appropriate for investigating learning progressions on astronomical systems, i.e., based on item fit analysis, students' responses to items were consistent with the measurement of Rasch model. Wright map analysis also represented that the assessment items were very effective in examining students' hypothetical pathways of development of understanding astronomical systems. At the lower anchor of the learning progression, while students perceived the change of location and direction of celestial bodies with only two-dimensional earth-based view, they failed to connect the locations of celestial bodies with Earth-Moon system model, and they could recognized simple patterns of planets in the solar system and milky way. At the intermediate levels, students interpreted celestial motion using the model of Earth rotation and revolution, Earth-Moon system, and solar system with space-based view, and they could also relate the elements of astronomical structures with the models. At the upper anchor, students showed the perspective change between space-based view and earth-based view, and applied it to celestial motion of astronomical systems, and they understood the correlation among sub-elements of astronomical systems and applied it to the system model.

• Journal of the Korean Society of Earth Science Education
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• v.13 no.2
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• pp.162-174
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• 2020

This study aimed to develop a creative education class program using metaphor, one of the creative thinking techniques, and to examine the effectiveness of the program targeting for randomly sampled 338 students in six middle schools. The creative education class program with the metaphor was developed based on content elements concerning 'astronomy' in 2015 science curriculum revision in South Korea. The program was tested for validity after being modified and supplemented three times by forming a group of experts, and the final version of the program was applied to school education fields during four periods, including block time. To find out the effectiveness of the program and the implementation, creative education class satisfaction test and creative thinking process test were conducted. That is to say, the creative education class satisfaction test was conducted before treatment and the creative thinking process test was implemented both before and after treatment. The results of the study are as follows. First, in this study, the program was developed with the emphasis on students voluntarily and actively participating in creative education programs while utilizing creative thinking methods. Second, the statistical results of the pre- and post-class about the creative education program using the metaphor of creative thinking techniques represented significant results(p<.05). In other words, the two-dependent samples by students' pre-and post-score about the creative education class showed significant statistical test results (p<.05). It turned out that the creative education program using metaphor has had a positive impact on research participants. Third, in regards to the results of the creative education class satisfaction test, 101 out of 338 students(30%) answered 'Strongly Agree' and 137(41%) answered 'Agree', indicating the subjects' satisfaction with the class was high in general. On the other hand, concerning difficulties of the creative class, 137(41%) answered "Lack of time" as the main factor, followed by 98(30%) "Difficulties of problems they were required to solve", 73(22%) answered "Conflicts with friends", and 24(7%) said "Difficulties of contents." These responses were taken into account as considerations for further development of creative education programs.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.242-248
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• 2007

Purpose: To study the effect of recombinant human epidermal growth factor (rhEGF) on oral mucositis induced by cisplatin and radiotherapy in a mouse model. Materials and Methods: Twenty-four ICR mice were divided into three groups-the normal control group, the no rhEGF group (treatment with cisplatin and radiation) and the rhEGF group (treatment with cisplatin, radiation and rhEGF). A model of mucositis induced by cisplatin and radiotherapy was established by injecting mice with cisplatin (10 mg/kg) on day 1 and with radiation exposure (5 Gy/day) to the head and neck on days $1{\sim}5$. rhEGF was administered subcutaneously on days -1 to 0 (1 mg/kg/day) and on days 3 to 5 (1 mg/kg/day). Evaluation included body weight, oral intake, and histology. Results: For the comparison of the change of body weight between the rhEGF group and the no rhEGF group, a statistically significant difference was observed in the rhEGF group for the 5 days after day 3 of. the experiment. The rhEGF group and no rhEGF group had reduced food intake until day 5 of the experiment, and then the mice demonstrated increased food intake after day 13 of the of experiment. When the histological examination was conducted on day 7 after treatment with cisplatin and radiation, the rhEGF group showed a focal cellular reaction in the epidermal layer of the mucosa, while the no rhEGF group did not show inflammation of the oral mucosa. Conclusion: These findings suggest that rhEGF has a potential to reduce the oral mucositis burden in mice after treatment with cisplatin and radiation. The optimal dose, number and timing of the administration of rhEGF require further investigation.

• Journal of Korea Game Society
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• v.4 no.4
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• pp.11-18
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• 2004

The on-line games in the past were played by only two persons exchanging data based on one-to-one connections, whereas recent ones (e.g. MMORPG: Massively Multi-player Online Role-playings Game) enable tens of thousands of people to be connected simultaneously. Specifically, Korea has established an excellent network infrastructure that can't be found anywhere in the world. Almost every household has a high-speed Internet access. What made this possible was, in part, high density of population that has accelerated the formation of good Internet infrastructure. However, this rapid increase in the use of on-line games may lead to surging traffics exceeding the limited Internet communication capacity so that the connection to the games is unstable or the server fails. expanding the servers though this measure is very costly could solve this problem. To deal with this problem, the present study proposes the load distribution technology that connects in the form of local clustering the game servers divided by their contents used in each on-line game reduces the loads of specific servers using the load balancer, and enhances performance of sewer for their efficient operation. In this paper, a cluster system is proposed where each Game server in the system has different contents service and loads are distributed efficiently using the game server resource information such as CPU utilization. Game sewers having different contents are mutually connected and managed with a network file system to maintain information consistency required to support resource information updates, deletions, and additions. Simulation studies show that our method performs better than other traditional methods. In terms of response time, our method shows shorter latency than RR (Round Robin) and LC (Least Connection) by about 12%, 10% respectively.

• Journal of The Korean Association For Science Education
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• v.24 no.3
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• pp.519-531
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• 2004

In recent years, there has been an increased emphasis on performance assessment to evaluate students' abilities. Our nation has introduced a change in testing and assessment. Additional work on the efficacy, reliability, and comparability in order to develop the performance assessment item has been needed in the enforcement of the 7th National Science Curriculum. Also, criteria for professional and technical standards has been needed to be developed. The purpose of this study was to draw out various key concepts and to develop achievement standards, assessment standards and performance assessment items based on the 7th National Science Curriculum on the subject matter of reproduction(chapter 13) and biological accumulation(chapter 17). And also, this study examined the validity of completed performance assessment items based on classical test theory and polytomous item response theory. Twelve key concepts in chapter 13(reproduction) and four from chapter 17(biological accumulation) were abstracted. Twenty-six achievement standards in chapter 13(reproduction), and nine in chapter 17(biological accumulation) were developed. The achievement standards were determined in terms of knowledge(K), process skill(P) and attitude(A). Twenty-five assessment standards in chapter 13(reproduction) and nine in chapter 17(biological accumulation) were developed. Based on the developed achievement standards and assessment standards, twenty-two performance assessment items(seventeen open-ended questions, three essays, and two portfolios) with concrete grading criteria were developed. Eight open-ended items were applied to 240 10th graders to evaluate reliabilities of the test which consisted of four items per each chapter. The results would be suggested that the applied items were valid for performance assessment because item difficulties and item discriminations were proper. There was not much differences in item discrimination between interpretation from classical test theory and that from polytomous item response theory. However, there were some differences in item difficulties between the interpretations of two theories because the characteristics of examinees were reflected in classical test theory.