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Waterbody Detection for the Reservoirs in South Korea Using Swin Transformer and Sentinel-1 Images (Swin Transformer와 Sentinel-1 영상을 이용한 우리나라 저수지의 수체 탐지)

  • Soyeon Choi;Youjeong Youn;Jonggu Kang;Seoyeon Kim;Yemin Jeong;Yungyo Im;Youngmin Seo;Wanyub Kim;Minha Choi;Yangwon Lee
    • Korean Journal of Remote Sensing
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    • v.39 no.5_3
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    • pp.949-965
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    • 2023
  • In this study, we propose a method to monitor the surface area of agricultural reservoirs in South Korea using Sentinel-1 synthetic aperture radar images and the deep learning model, Swin Transformer. Utilizing the Google Earth Engine platform, datasets from 2017 to 2021 were constructed for seven agricultural reservoirs, categorized into 700 K-ton, 900 K-ton, and 1.5 M-ton capacities. For four of the reservoirs, a total of 1,283 images were used for model training through shuffling and 5-fold cross-validation techniques. Upon evaluation, the Swin Transformer Large model, configured with a window size of 12, demonstrated superior semantic segmentation performance, showing an average accuracy of 99.54% and a mean intersection over union (mIoU) of 95.15% for all folds. When the best-performing model was applied to the datasets of the remaining three reservoirsfor validation, it achieved an accuracy of over 99% and mIoU of over 94% for all reservoirs. These results indicate that the Swin Transformer model can effectively monitor the surface area of agricultural reservoirs in South Korea.

Problem Analysis of the Experiments Illustrating pH Effects on Enzyme Activities in High School Science Textbooks - Focus on Starch-Iodine Reaction - (고등학교 과학 교과서에서 "pH가 효소의 작용에 미치는 영향" 실험의 문제점 분석 -녹말과 요오드 반응을 중심으로-)

  • Ji, Jae-Hwa;Jeong, Dae-Hong
    • Journal of The Korean Association For Science Education
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    • v.29 no.8
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    • pp.923-933
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    • 2009
  • In this study, analysis was carried out on science experiment in high school textbooks, illustrating 'the effect of pH on enzyme activity.' Five of the total 16 science textbooks introduced in this experiment, and the experimental conditions therein were analyzed. Textbook analysis revealed that pH of below 3 was used for 'acidic condition' and that of over 11 was used for 'basic' condition. Using the experimental conditions described in the textbooks, review experiments were performed. Buffering effect with the addition of saliva was found in the pH region around 7 when buffer solution was not used to control pH as was in the textbooks. The enzyme activity experiments were performed controlling pH from pH 2 to 13 with buffer. The color of the sample was blue from pH 2 to 4, and then disappeared from pH 5 to 8, reflecting that starch was digested owing to enzyme activity. In pH 9 light blue color appeared, indicating de-activation of enzyme under this basic condition. However, the blue color of the sample became lighter at pH 10 and disappeared from pH 11, which was different from the expected behavior anticipating dark blue color due to de-activation of enzyme under strong basic condition. These results can wrongly influence students to interpret that enzyme can be activated in this pH condition. So, we analyzed the reason for the color of the sample turning light blue in pH 10 and disappeared from pH 11. The analysis resulted that ${I_3}^-$ and/or ${I_5}^-$ subunits of polyiodides within the starch helix in starch-iodine complex, showing blue, decreases above pH 10 due to disproportionation to HOI, ${IO_3}^-$, and $I^-$ by the reaction with $OH^-$.

A Grounded theory Approach on the Experience of Sexual Abuse Victims (성폭력 피해여성의 경험에 관한 연구)

  • Kim, Kyung-Hee;Nam, Sun-Young;Chee, Soon-Ju;Kwon, Hye-Jin;Chung, Yeon-Kang
    • Journal of the Korean Society of School Health
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    • v.9 no.1
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    • pp.77-98
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    • 1996
  • This studies designed to work out a theoretical framework on the experience of sexual abuse from the perspective of grounded theory in an effort to provide more practical and efficient nursing intervention for female victims. The subcategories identified were "sexual abuse", "threatening", "absent mindness", "embarrassment", "horripilation", "dizziness", "wondrousness", "filthiness", "sexual curiosity", "violence level", "victim's age", "neighbors response", "victims personality", "common experience", "sexual abuse information", "family relations", "level of familiarity", "hiding", "suppression", "self-torture", "self-protection", "avoidance", "asking aid", "withdrawal", "hatred", "confusion", "dodging, "remmant", and "pursuing". The 29 subcategories given above were further integrated into 16 categories such as "victimizedness", "being astounded", "filthiness", "degree", "developmental stage", "response pattern", "personality", "rarity", "information availability", "family support", "cover-up", "escaping", "informing", "negative internalization", and "positive pursuit of change". The core categories linked to all the other categories turned out to be "being taken aback" and "filthiness" incorporating the relevant subcategories. A total of 23 theoretical hypothesis emerged in the process of analyzing data. 1. the grater sexual curiosity, the weaker the senses of being taken aback and filthiness. 2. The weaker sexual curiosity, the stronger the senses of being taken aback and filthiness. 3. The stronger the level of violence, The more violent the senses of being taken aback and filthiness. 4. The lower the level of violence, the weaker the senses of being taken aback and filthiness. 5. The younger the victims, the stronger the senses of being taken aback and filthiness. 6. The older the victims, The weaker the senses of being taken aback and filthiness. 7. 'Escaping' will transpire regardless of the given circumstances. 8. The weaker the senses of being taken aback and filthiness, the more probable 'informing' and 'escaping' transpire. 9. The stronger the senses of being taken aback and filthiness, the more probable 'informing' and 'escaping' transpire. 10. The more protective the response from 'informing' and 'escaping' transpire around, the more likely the response to being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 11. The more repelling the response from around, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 12. The more open minded the personality of the subject, the more likely the response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 13. The more closed the personality of tile subject, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 14. The more frequent the experience of sexual abuse, the more likely the response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 15. The less frequent the experience of sexual abuse, the more lilely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 16. The more available information concerning sexual abuses, the more likely response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping. 17. The less available information concerning sexual abuses, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 18. The more cohesive the family of the subject, the more likely the response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 19. The less cohesive the family of the subject, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 20. The less familiar the subject is with the abuser, the more likely the response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 21. The less familiar the subject is with the abuser, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping. 22. The more likely the response to 'being taken aback' and 'filthiness' is 'informing and 'escaping', the more positive changes the subject will pursue. 23. The more likely the response to 'being taken aback' and 'filthiness' is 'covering-up' and 'escaping', the more negative changes the subject will pursue. The following four hypotheses were conformed in the process of data analysis. 1) In case the level of violence is strong but 'being taken aback' and 'filthiness' in weak because of strong sexual curiosity and also if information concerning sexual abuse is not readily available and the frequency is low, negative internationalization marked by 'covering-up' and 'escaping' will take place despite the fact the subject is open-minded, the family is cohesive and the abuser is unfamiliar. 2) In case the level of violence is weak but 'being taken aback' and 'filthiness' is weak combined with weak sexual curiosity and also if information concerning sexual abuse is readily available and the response from around is protective and the frequency is high, the subject will pursue positive changes to 'being taken aback' and 'filthiness', further aided by the fact that the subject is open-minded, the family is cohesive and the abuser is unfamiliar. 3) In case the level of violence is strong and 'being taken abuse' and 'filthiness' is strong because of weak sexual curiosity and also if information concerning sexual abuse is reading available and the response from around is readily available and the response from around is protective and the frequency is low, the subject will persue positive changes marked by 'informing' and 'escaping' despite the fact that the family cohesion is weak and the abuser is familiar. 4) In case the level of violence is strong and 'being taken aback' and 'filthiness' is strong because of weak sexual curiosity and also if information concerning sexual abuse is not readily available and the response from around is respelling and the frequency is low negative internalization like 'covering-up' and 'escaping' will take place, further aggravated by the fact that the subject's personality is closed, family cohesion is weak, and subject is familiar. On the basis of the above finding, it is recommended that nursing intervention should focus on promoting the milieu conductive to the victims pursuing positive changes along with the adequate aids from protection facilities as well as from the people around them.

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Characteristics and classification of paddy soils on the Gimje-Mangyeong plains (김제만경평야(金堤萬頃平野)의 답토양특성(沓土壤特性)과 그 분류(分類)에 관(關)한 연구(硏究))

  • Shin, Yong Hwa
    • Korean Journal of Soil Science and Fertilizer
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    • v.5 no.2
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    • pp.1-38
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    • 1972
  • This study, designed to establish a classification system of paddy soils and suitability groups on productivity and management of paddy land based on soil characteristics, has been made for the paddy soils on the Gimje-Mangyeong plains. The morphological, physical and chemical properties of the 15 paddy soil series found on these plains are briefly as follows: Ten soil series (Baeggu, Bongnam, Buyong, Gimje, Gongdeog, Honam, Jeonbug, Jisan, Mangyeong and Suam) have a B horizon (cambic B), two soil series (Geugrag and Hwadong) have a Bt horizon (argillic B), and three soil series (Gwanghwal, Hwagye and Sindab) have no B or Bt horizons. Uniquely, both the Bongnam and Gongdeog series contain a muck layer in the lower part of subsoil. Four soil series (Baeggu, Gongdeog, Gwanghwal and Sindab) generally are bluish gray and dark gray, and eight soil series (Bongnam, Buyong, Gimje, Honam, Jeonbug, Jisan, Mangyeong and Suam) are either gray or grayish brown. Three soil series (Geugrag, Hwadong and Hwagye), however, are partially gleyed in the surface and subsurface, but have a yellowish brown to brown subsoil or substrata. Seven soil series (Bongnam, Buyong, Geugrag, Gimje, Gongdeog, Honam and Hwadong) are of fine clayey texture, three soil series (Baeggu, Jeonbug and Jisan) belong to fine loamy and fine silty, three soil series (Gwanghwal, Mangyeong and Suam) to coarse loamy and coarse silty, and two soil series (Hwagye and Sindab) to sandy and sandy skeletal texture classes. The carbon content of the surface soil ranges from 0.29 to 2.18 percent, mostly 1.0 to 2.0 percent. The total nitrogen content of the surface soil ranges from 0.03 to 0.25 percent, showing a tendency to decrease irregularly with depth. The C/N ratio in the surface soil ranges from 4.6 to 15.5, dominantly from 8 to 10. The C/N ratio in the subsoil and substrata, however, has a wide range from 3.0 to 20.25. The soil reaction ranges from 4.5 to 8.0. All soil series except the Gwanghwal and Mangyeong series belong to the acid reaction class. The cation exchange cpacity in the surface soil ranges from 5 to 13 milliequivalents per 100 grams of soil, and in all the subsoil and substrata except those of a sandy texture, from 10 to 20 milliequivalents per 100 grams of soil. The base saturation of the soil series except Baeggu and Gongdeog is more than 60 percent. The active iron content of the surface soil ranges from 0.45 to 1.81 ppm, easily-reduceable manganese from 15 to 148 ppm, and available silica from 36 to 366 ppm. The iron and manganese are generally accumulated in a similar position (10 to 70cm. depth), and silica occurs in the same horizon with that of iron and manganese, or in the deeper horizons in the soil profile. The properties of each soil series extending from the sea shore towards the continental plains change with distance and they are related with distance (x) as follows: y(surface soil, clay content) = $$-0.2491x^2+6.0388x-1.1251$$ y(subsoil or subsurface soil, clay content) = $$-0.31646x^2+7.84818x-2.50008$$ y(surface soil, organic carbon content) = $$-0.0089x^2+0.2192x+0.1366$$ y(subsoil or subsurface soil, pH) = $$-0.0178x^2-0.04534x+8.3531$$ Soil profile development, soil color, depositional and organic layers, soil texture and soil reaction etc. are thought to be the major items that should be considered in a paddy soil classification. It was found that most of the soils belonging to the moderately well, somewhat poorly and poorly drained fine and medium textured soils and moderately deep fine textured soils over coarse materials, produce higher paddy yields in excess of 3,750 kg/ha. and most of the soils belonging to the coarse textured soils, well drained fine textured soils, moderately deep medium textured soils over coarse materials and saline soils, produce yields less than 3,750kg/ha. Soil texture of the profile, available soil depth, salinity and gleying of the surface and subsurface soils etc. seem to be the major factors determining rice yields, and these factors are considered when establishing suitability groups for paddy land. The great group, group, subgroup, family and series are proposed for the classification categories of paddy soils. The soil series is the basic category of the classification. The argillic horizon (Bt horizon) and cambic horizon (B horizon) are proposed as two diagnostic horizons of great group level for the determination of the morphological properties of soils in the classification. The specific soil characteristics considered in the group and subgroup levels are soil color of the profile (bluish gray, gray or yellowish brown), salinity (salic), depositonal (fluvic) and muck layers (mucky), and gleying of surface and subsurface soils (gleyic). The family levels are classified on the basis of soil reaction, soil texture and gravel content of the profile. The definitions are given on each classification category, diagnostic horizons and specific soil characteristics respectively. The soils on these plains are classified in eight subgroups and examined under the existing classification system. Further, the suitability group, can be divided into two major categories, suitability class and subclass. The soils within a suitability class are similar in potential productivity and limitation on use and management. Class 1 through 4 are distinguished from each other by combination of soil characteristics. Subclasses are divided from classes that have the same kind of dominant limitations such as slope(e), wettness(w), sandy(s), gravels(g), salinity(t) and non-gleying of the surface and subsurface soils(n). The above suitability classes and subclasses are examined, and the definitions are given. Seven subclasses are found on these plains for paddy soils. The classification and suitability group of 15 paddy soil series on the Gimje-Mangyeong plains may now be tabulated as follows.

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Possibility of Establishing an International Court of Air and Space Law (국제항공우주재판소의 설립 가능성)

  • Kim, Doo-Hwan
    • The Korean Journal of Air & Space Law and Policy
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    • v.24 no.2
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    • pp.139-161
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    • 2009
  • The idea of establishing an International Court of Air and Space Law (hereinafter referred to ICASL) is only my academic and practical opinion as first proposal in the global community. The establishment of the International Court of Air and Space Law can promote the speed and promote fairness of the trial in air and space law cases. The creation of an ICASL would lead to strengthening of the international cooperation deemed essential by the global community towards joint settlement in the transnational air and space cases, claims and would act as a catalyst for the efforts and solution on aircraft, satellite and space shuttle's accidents and cases and all manpower, information, trial and lawsuit to be centrally managed in an independent fashion to the benefit of global community. The aircraft, satellite and spacecraft's accidents attributes to the particular and different features between the road, railway and maritime's accidents. These aircraft, satellite and spacecraft's accidents have incurred many disputes between the victims and the air and space carriers in deciding on the limited or unlimited liability for compensation and the appraisal of damages caused by the aircraft's accidents, terror attack, satellite, space shuttle's accidents and space debris. This International Court of Air and Space Law could hear any claim growing out of both international air and space crash accidents and transnational accidents in which plaintiffs and defendants are from different nations. This alternative would eliminate the lack of uniformity of decisions under the air and space conventions, protocols and agreements. In addition, national courts would no longer have to apply their own choice of law analysis in choosing the applicable liability limits or un-limit for cases that do not fall under the air and space system. Thus, creation of an International Court of Air and Space Law would eliminate any disparity of damage awards among similarly situated passengers and shippers in nonmembers of air and space conventions, protocols, agreements and cases. Furthermore, I would like to explain the main items of the abovementioned Draft for the Convention or Statute of the International Court of Air and Space Law framed in comparison with the Statute of the International Court of Justice, the Statue of the International Tribunal for the Law of the Sea and the Statute of the International Criminal Court. First of all, in order to create the International Court of Air and Space Law, it is necessary for us to legislate a Draft for the Convention on the Establishment of the International Court of Air and Space Law. This Draft for the Convention must include the elected method of judges, term, duty and competence of judge, chambers, jurisdiction, hearing and judgment of the ICASL. The members of the Court shall be elected by the General Assembly and Council of the ICAO and by the General Assembly and Legal Committee of the UNCOPUOS from a list of persons nominated by the national groups in the six continent (the North American, South American, African, Oceania and Asian Continent) and two international organization such as ICAO and UNCOPUOS. The members of the Court shall be elected for nine years and may be re-elected as one time. However, I would like to propose a creation an International Court of Air and Space Law in extending jurisdiction to the International Court of Justice at the Hague to in order to decide the air and space convention‘s cases. My personal opinion is that if an International Court on Air and Space Law will be created in future, it will be settled quickly and reasonably the difficulty and complicated disputes, cases or lawsuit between the wrongdoer and victims and the injured person caused by aircraft, satellite, spacecraft's accidents or hijacker and terrorists etc. on account of deciding the standard of judgment by judges of that’s court. It is indeed a great necessary and desirable for us to make a new Draft for the Convention on a creation of the International Court of Air and Space Law to handle international air and space crash litigation. I shall propose to make a new brief Draft for the Convention on the Creation of an International Court of Air and Space Law in the near future.

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Field Application of Waterworks Automatic Meter Reading and Analysis of Household Water Use (상수도 원격검침시스템의 현장 적용성 평가 및 가정용수 사용량 분석)

  • Joo, Jin Chul;Ahn, Hosang;Ahn, Chang Hyuck;Ko, Kyung-Rok;Oh, Hyun Je
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.10
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    • pp.656-663
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    • 2012
  • After the construction of waterworks automatic meter reading with 15 mm diameter digital water mater with magnetoresistance sensor developed in this study at 96 households of apartment complexes located in Incheon-City B-Gu S-Dong, the feasibility of field application of waterworks automatic meter reading was evaluated. The field application of waterworks automatic meter reading was performed from July to December in 2011, and average reception rate was as low as 84.6% due to the instable wibro networks, the existence of communication blackout and temporary malfunction of router. After the extraction of 10 households with one to five residents out of 96 households by using stratified random sampling method and analysis of domestic water use, it was found that domestic water use was significant at August and showed a decreasing trend at September, followed by increase in domestic water use at November and decrease in domestic water use at December. This phenomenon should be attributed to weather factors (temperature, humidity, etc.), which significantly affected domestic water use. Similar trend in domestic water use in terms of weather factors was obtained in case of Liter per capita day of water use after the extraction of 30 households out of 96 households by using stratified random sampling method. After analysis of Liter per capita day for 96 households, single residents increases resulted in reduction of domestic water usage by about 14% of Liter per capita day. These results might be due to the fact that domestic water usage such as laundry, beverages, catering, cleaning, etc. should be required for even the household with one resident, whereas domestic water usage for those common utilization can be significantly saved for the household with more than one resident.

Exploring Small Group Argumentation Shown in Designing an Experiment: Focusing on Students' Epistemic Goals and Epistemic Considerations for Activities (실험 설계에서 나타난 소집단 논변활동 탐색: 활동에 대한 인식적 목표와 인식적 이해를 중심으로)

  • Kwon, Ji-suk;Kim, Heui-Baik
    • Journal of The Korean Association For Science Education
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    • v.36 no.1
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    • pp.45-61
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    • 2016
  • The purpose of this study is to explore students' epistemic goals and considerations in designing an experiment task and to investigate how a shift in the students' epistemology affected their argumentation. Four 7th grade students were selected as a focus group. According to the results, when they designed their own experiment, their epistemic goal was 'scientific sense-making' and their epistemic considerations - the perception of the nature of the knowledge product was 'this experiment should explain how something happened', the perception of the justification was 'we need to use our interpretation of the data' and the perception of the audience was 'constructor' - contributed to designing their experiment actively. When students tried to select one argument, their epistemic goal shifted to 'winning a debate', showing 'my experiment is better than the others' with the perception of the audience, 'competitor'. Consequently, students only deprecated the limits of different experiment so that they did not explore the meaning of each experiment design deeply. Eventually, student A's experiment design was selected due to time restrictions. When they elaborated upon their result, their epistemic goal shifted to 'scientific sensemaking', reviewing 'how this experiment design is scientifically valid' through scientific justification - we need justification to make members accept it - acting as 'cooperator'. Consequently, all members engaged in a productive argumentation that led to the development of the group result. This study lays the foundation for future work on understanding students' epistemic goals and considerations to prompt productive argumentation in science classrooms.

The Study on Bone Mineral Density Measurement Error in Accordance with Change in ROI by Utilizing Dual Energy X-ray Absorptiometry (DEXA를 이용한 골밀도 측정시 검사자의 ROI 변화에 따른 골밀도 측정값의 오차에 관한 연구)

  • Lee, Yun-Hong;Lee, In-Ja;Yong, Hyung-Jin
    • Journal of radiological science and technology
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    • v.35 no.1
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    • pp.1-7
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    • 2012
  • Dual Energy X-ray Absorptiometry(DEXA) is commonly used to diagnose Osteoporosis. The errors of DEXA bone density operation are caused by operator, bone mineral density meter, blood testing, patient. We focus on operator error then study about how much influence operator's region of intest(ROI) in bone testing result. During from March to July in 2011. 50 patients ware selected respectively from 30, 40, 50, 60, and 70 age groups who came to Korea University Medical Center(KUMC) for their Osteoporosis treatment. A-test was performed with usually ROI and B-test was performed with most widely ROI. Then, We compare A-test and B-test for find maximum difference of T-score error which occurred operator ROI controlling. Standard deviation of T-score of B-test showed 0.1 higher then A-test in femur neck. Standard deviation of B-test showed 0.2 higher then A-test in Ward's area which in Greater trocanter and Inter trocanter. Standard deviation of B-test showed 0,1 lower then A-test in L-1. Bone density testing about Two hundred patients results are as follow. When operator ROI was changed wider than normal ROI, bone density of femur was measured more higher but bone density of L-spine was measured more lower then normal bone density. That means, sometime DEXA bone density testing result is dependent by operator ROI controlling. This is relevant with the patient's medicine and health insurance, thus, tester always keep the size of ROI for to prevent any problem in the patient.

Effects of Horseshoe Expander (Horseshoe Expander의 확장 효과에 관한 연구)

  • Chung, Kyu-Rhim;Park, Young-Guk;Lee, Young-Jun;Kim, Hong-Suk
    • The korean journal of orthodontics
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    • v.30 no.5 s.82
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    • pp.553-563
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    • 2000
  • Horseshoe Expander is one of Slow Maxillary Expansion(SME) which aims to accommodate the contra- lateral expansion and midpalatal suture expansion or the palate. The appliance consists of skeleton type strew embedded in split Horseshoe appliance. It is the objectives of the presentation to manifest the changes in dental & craniofacial components subsequent to the application of Horseshoe Expander. The subjects for this study consisted of 32 patients (mean age : 12.7). frontal, lateral cephalometric headfilm were taken and study casts were fabricated before and after expansion. 24 items were measured, compared preexpansion with postexpansion. Especially, palatal volume was measured by means of 'Hydro-measurement method'. Tooth axis measurement on the dental casts were made with Universal bevel protractor, and Horseshoe Expander group were compared with RME group. This study of changes to maxillary expansion with Horseshoe Expander revealed the following significant results. 1. Triangular-shaped expansion pattern appeared in frontal cephalometric headfilm. 2. Palatal plane, occlusal plane, mandibular plane and upper incisor to FH increased in lateral cephalometrir headfilm. 3. Palatal volume increased significantly. A slight bite opening, reduction of occlusal contact points showed in dental casts. 4. A 2.2:1 ratio of the amount of intermolar width in maxilla(orthodontic movement) to maxillary width (orthopedic movement) was determined. 5. Horseshoe Expander group has less buccal tipping tendency than RME group, by taking high correlation coefficients in the upper second premolar and first molar. It was suggested that Horseshoe Expander showed less orthodontic changes, less buccal tipping tendency. In addition, it was effective in maxillary expansion.

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Torque and mechanical failure of orthodontic micro-implant influenced by implant design parameters (교정용 마이크로 임플란트의 디자인이 토오크와 파절강도에 미치는 영향)

  • Yu, Won-Jae;Kyung, Hee-Moon
    • The korean journal of orthodontics
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    • v.37 no.3 s.122
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    • pp.171-181
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    • 2007
  • Objective: The present study was aimed at an analytical formulation of the micro-implant related torque as a function of implant size, i.e. the diameter and length, screw size, and the bony resistance at the implant to bone interface. Methods: The resistance at the implant to cancellous bone interface $(S_{can})$ was assumed to be in the range of 1.0-2.5 MPa. Micro-implant model of Absoanchor (Dentos Inc. Daegu, Korea) was used in the course of the analysis. Results: The results showed that the torque was a strong function of diameter, length, and the screw height. As the diameter increased and as the screw size decreased, the torque index decreased. However the strength index was a different function of the implant and bone factors. The whole Absoanchor implant models were within the safe region when the resistance at the implant/cancellous bone $(=S_{can})$ was 1.0 or less. Conclusion: For bone with $S_{can}$ of 1.5 MPa, the cervical diameter should be greater than 1.5 mm if micro-implant models of 12 mm long are to be placed. For $S_{can}$ of 2.0 MPa, micro-implant models of larger cervical diameter than 1.5 mm were found to be safe only if the endosseous length was less than 8 mm.