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Development of Acoustic Positioning System for ROV using SBL System (SBL방식을 이용한 무인잠수정의 수중초음파 위치측정시스템 개발)

  • Yu, Son-Cheol;Byun, Seung-Woo;Kim, Joon-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.3
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    • pp.808-814
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    • 2010
  • In this paper we executed a SBL(Short Baseline) underwater acoustic positioning system that is a kind of underwater position estimation system to estimates the 3-dimensional position of ROV(Remotely Operated Vehicle) using hydrophones and DAQ(Data Acquisition) system in the basin which dimensions are $3{\times}3{\times}1.7(m)$. For this experiment, we let 4 hydrophones in different positions of the basin for receiver and 1 hydrophone is fixed on the underwater vehicle for transmitting sensor(pinger). These five hydrophones are communicated with each other to find the 3-D positions of the moving ROV in the basin. The measured signals are collected by DAQ system and the positions of the ROV are plotted by LabView program in real-time. To estimate the position of the ROV we used a trigonometric method. In X and Y plane the estimated data has a small errors but in Z plane the estimated data has large errors so we cannot use this data for position control. One solution of this problem is using depth sensor that implemented of the underwater vehicle. Hereafter, we will test in the ocean using designed SBL system.

Determining Input Values for Dragging Anchor Assessments Using Regression Analysis (회귀분석을 이용한 주묘 위험성 평가 입력요소 결정에 관한 연구)

  • Kang, Byung-Sun;Jung, Chang-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.6
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    • pp.822-831
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    • 2021
  • Although programs have been developed to evaluate the risk of dragging anchors, it is practically difficult for VTS(vessel traffic service) operators to calculate and evaluate these risks by obtaining input factors from anchored ships. Therefore, in this study, the gross tonnage (GT) that could be easily obtained from the ship by the VTS operators was set as an independent variable, and linear and nonlinear regression analyses were performed using the input factors as the dependent variables. From comparing the fit of the polynomial model (linear) and power series model (nonlinear), the power series model was evaluated to be more suitable for all input factors in the case of container ships and bulk carriers. However, in the case of tanker ships, the power supply model was suitable for the LBP(length between perpendiculars), width, and draft, and the polynomial model was evaluated to be more suitable for the front wind pressure area, weight of the anchor, equipment number, and height of the hawse pipe from the bottom of the ship. In addition, all other dependent variables, except for the front wind pressure area factor of the tanker ship, showed high degrees of fit with a coefficient of determination (R-squared value) of 0.7 or more. Therefore, among the input factors of the dragging anchor risk assessment program, all factors except the external force, seabed quality, water depth, and amount of anchor chain let out are automatically applied by the regression analysis model formula when only the GT of the ship is provided.

An Archival Study on the Arrangement and Description of Old Document(Diploma) (고문서 정리(整理)에 대한 기록학적 연구 - 새로운 고문서 정리 방법의 모색을 위하여 -)

  • Cho, Kyung-Koo
    • The Korean Journal of Archival Studies
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    • no.7
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    • pp.37-74
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    • 2003
  • An Old document(Diploma) is a historical and unique record, so it must be collected, arranged, and preserved for research as soon as possible. Especially, for the effective use of the Old Document(Diploma), it is needed to arrange and describe the material systematically on the ground of modern archival theory. The Kyujanggak Archives in the Seoul National University has published 23 volumes of Old document(Diploma) material Old Document(Diploma). But they seem to cause the readers inconvenience, because the materials are classified and gathered only by genre, the titles or the orders of the materials are not standardized, and there is no description about the content of each Old document(Diploma). Jangseo-gak Library in The Academy of Korean Studies has also published the series of Old document(Diploma) material Old Document(Diploma) Collection. However the case is not different, since they are all mixed up with materials classified and gathered by genre, family, academy, or local school. And a great part of the materials have no titles and no description about the content of each Old document(Diploma), either. About the arrangement and description of the records, European and American archival science has established the theory of l)the principle of provenance, 2)the principle of original order, 3)levels of control, 4)collective description. These theories are valuable for the effective use of Old document(Diploma). On the viewpoint of the principle of provenance, Old document(Diploma) materials should not be classified by subject and genre, but by family and person. Then, the Old document(Diploma) materials, after collected by the unit of family or person on the viewpoint of the principle of provenance, should be arranged in their original order for more detailed arrangement and furthermore, for the work to find their relationship. This is so called the principle of original order. The hierarchical management of the Old document(Diploma) materials, for example, classifying by record group, sub-group, series, item and so on, is the concept of the levels of control, and comprehensive description of the each hierarchical structure is the concept of the collective description. Let's apply these archival theories to 34 pieces of the Chung, Man-Seok's material in the series of Old document(Diploma) material Old Document(Diploma). First, collect the Old document(Diploma) materials into Chung, Man-Seok's collection(the principle of provenance), which were scattered in the series classified by genre. Secondly, rearrange them chronologically(the principle of original order), and then we can find the comprehensive information about Chung, Man-Seok. For the hierarchical management of the Old document(Diploma) materials, we should establish a few concepts from the general, large group to specific, small item. The concepts can be organized as following; l)record group(Chung, Man-Seok record group) - 2)sub-group(personnel document, property document, family document, social activity document, political activity document, etc) - 3)series(gyoji-series, gyoseo-series, yuji-series etc. in the personnel document) - 4)folder(document with additions) - 5)item(one document). According to the the theory of the collective description, in the level of record group, there should be a collective description of Chung, Man-Seok's biography or a summary of record group. Similarly, there should be a collective description of a summary of sub-group in the level of sub-group and a summary of series in the level of series.

A Critical Essay on 'new cold war' Discourses: The Political Consequences of the 'cold peace' ('신냉전(new cold war)' 담론에 관한 비판적 소론: '차가운 평화(cold peace)'의 정치적 결과)

  • Jun-Kee BAEK
    • Analyses & Alternatives
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    • v.7 no.3
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    • pp.27-59
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    • 2023
  • This study aims to serve as a critical comparison of the currently controversial 'new cold war' discourse. It took three triggers for the 'new cold war' discourse to emerge as a major issue in the media and academia and to have real political impact. With the launch of China's 'Belt and Road' project and Russia's annexation of Crimea leading to the 'Ukraine crisis,' the 'new cold war' discourse has begun to take shape. Trump's U.S.-China trade spat has brought the 'new cold war' debate to the forefront. The 'new cold war' debate is currently being intensified by the Biden administration's framing of "democracy versus authoritarianism" and Putin's invasion of Ukraine. Currently, there is no consensus among scholars on whether the controversial 'new cold war' is a new version, or a continuation of the historically defined concept of the Cold War. The term 'New Cold War' is less of an analytical concept and more of a topical term that has yet to achieve analytical status, let alone a theoretical validation and systematization, and the related debate remains at the level of assertion or discourse. Through this comparative analysis, I will argue that the ongoing discourse of the 'New Cold War' does not have the instrumental explanatory power to analyze the transitional phenomena of the world order today.

Developing and Implementing a Secondary Teacher Training Program to Build TPACK in Entrepreneurship Education (기업가정신 교육에서의 TPACK 강화를 위한 중등 교사 연수 프로그램 개발 및 적용)

  • Seonghye Yoon;Seyoung Kim
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.4
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    • pp.51-63
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    • 2023
  • The purpose of this study is to develop and implement a secondary teacher training program based on the TPACK model to strengthen the capacity of teachers of youth entrepreneurship education in the context of the increasing importance of entrepreneurship as a future competency, and to provide theoretical and practical implications based on it. To this end, a teacher training program was developed through the process of analysis, design, development, implementation, and evaluation based on the ADDIE model, and 22 secondary school teachers in Gangwon Province were trained and the effectiveness and validity were analyzed. First, the results of the paired sample t-test of TPACK in entrepreneurship education conducted before and after the program showed statistically significant improvements in all sub-competencies. Second, the satisfaction survey of the training program showed that the overall satisfaction was high with M=4.83. Third, the validity of the program was reviewed by three experts, and it was found to be highly valid with a validity of M=5.0, usefulness of M=4.7, and universality of M=5.0. Based on the results, it is suggested that in order to expand entrepreneurship education, opportunities for teachers' holistic capacity building such as TPACK should be expanded, teachers' understanding and practice of backward design should be promoted, and access to various resources that can be utilized in entrepreneurship education should be improved.

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Analytical studies of bovine mastitis management by standard plate counts(SPC) and somatic cell counts(SCC) (젖소 유방염 관리에 따른 세균 및 체세포수 등급 실태 조사 분석)

  • 허정호;정명호;박영호;조명희;이주홍
    • Korean Journal of Veterinary Service
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    • v.21 no.3
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    • pp.285-300
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    • 1998
  • 1. The number of average milking cows, clinical forms of mastitis, mastitis-developing cows, and cows killed by mastitis a year were 25.7, 1.8(7%), 6.3(26%), and 2.7(10.1%)heads, respectively. The annual grade changes of standard plate counts(SPC) and somatic cell counts(SCC) showed the grade 1A of SPC diminished sharply from April to August, we think it was due to the lack of proper management in farming season and the grade 3 of SCC indirectly influenced increased in huge during August. 2. The average number of parturitions of farms was 2.3, but 50% of below 1 parturition were 22 farms(31%), 50% of above 3 parturitions were 16(23%) out of 71 farms. According to grades of the number of parturitions of milking cows per each farm, the farms' grades recording 3 parturitions and 50% were little bit excellent. 3. The actual situation research of foremilking CMT revealed 35 out of 74 farmer didn't do CMT Among them(35 out of 74 farmers), 80% did not test thanks to the troublesome process of the CMT. SCC grade 3, among farms who did foremilking CMT once or twice a month and who did not were 29% and 40% respectively and SPC grade 1A were 55% and 9%, respectively. 4. The research of actual situation on milking management let us know 29 farms(39%) did not do lastmilking, 37 farms(49%) usually did overmilking, and 34 farms(46%) did milking for 4 or 5 minutes. Grades according to average requiring times of milking showed SCC grade 1 of farms milking within 7 minutes was 11% and SPC grade 1A was 34%, on the other side, farms milking more than 7 minutes were 0% in SCC grade 1 and 13% in SPC grade 1A. Grades according to the starting time of milking after rubbing teats showed SPC grade 1A of farms starting milking at about 1 minute and over 2 minutes were 50% and 20%, respectively. 5. The research of actual situation on hygienic milking management uncovered 65 farms(88%) were using one towel which was used in washing teats and udders to wash more than 3 to 4 cows, and 53 farms(72%) were using one dried towel to dry udders not for each cow but for more than 3 to 4 cows after washing. Also, on milking turns disclosed 30 farms(40%) were milking cows in the order of incoming without isolation of a dominant group. According to grades of towels used in washing teats and udders, farms using a towel for each cow were 56% and a towel for over 3 cows were 31% in SPC grade 1A. According to using-or-not grades of dried towels after washing udders, farms using a towel for each cow were 79% and a towel for over 3 cows were 21% in SPC grade 1A. 6. Farms doing teat-dipping before milking were 7(10%), not doing teat-dipping after milking, or doing sometimes were 9(12%), and doing right after milking were 57(77%). And farms doing teat-dipping after dry cows and before delivery were 21(28a ). Farms using bethadine as an antiseptic solution were 70(95%), 40 farms(59%) diluted it with water as weak as 5 to 10 times, and on drying cows 64 farms(87%) slowly did it more than 2 days. Grade 1A of SPC of farms doing teat-dipping at every milking was 38%, farms doing occasionally or not was 33%, and farms doing it right after milking was 37% and doing after milking more than 5 cows was 20%. Grade 1A of SPC among farms diluting bethadine 5 times and diluting 5 to 10 times with water were 36% and 33%, respectively, and Grade 3 of SCC were 35% and 32%, respectively. 7. Studies on nonlactating period medical treatment, as the cows were on dry, 54 farms treated with their own hands.73 farms(98%) had bovine mastitis treated for themselves. And on applying medicines against mastitis, 55 farmers chose them on the basis of their own experience, 42 farms(57%) were treated more than 3 days. 41 farms(55%) dumped away the mastitis infected milk separately, 24 farms(32%) were feeding and milking at the same time. 8. Fifty-six farms(76%) always washed and disinfected milking machines after milking. Farms using the milking machines at low, or variable vacuum pressures, or at the vacuum pressure, set at the moment of its installation were 31(42%), and farms that did not know pulsation ratio were 27(37%). Farms changing liners when they were torn 8(11%), 58 farms(78%) said they checked milking system when there were wrong with them, 31 farms(42%) changed milking hoses when they found out problems, and 42 farms(57%) cleaned vacuum and milking systems when they felt dirty. The SPC grade 1A of farms washing and sterilizing milking machines was 38% and farms only washing was 28%.

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Study for Diagnostic Correspondent Rates between DSOM and Oriental Medical Doctors (한방진단시스템과 진단의 간의 진단일치도 연구)

  • Lee, In-Seon;Lee, Yong-Tae;Chi, Gyoo-Yong;Kim, Jong-Won;Kim, Kyu-Kon
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.6
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    • pp.1359-1367
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    • 2008
  • DSOM(Diagnosis System of Oriental Medicine) was made as a computerized assistant program for oriental medicine doctors to be able to diagnose with statistical basis. Then DSOM uses questionnaires filled out by subjects without enough explanatory guide. If the subject misunderstand the meaning of the passages, we might not rely on that result. So I designed this study to investigate the diagnostic correspondent rates between DSOM and practitioners. First, let the respondents answer to DSOM(DSOM-Ⅰ for the rest). After that, three doctors diagnosed the respondents and marked how much they had symptoms about 16 pathogenic factors in the score range 0${\sim}$5('0' means they didn't have that symptom, '1' means they had that symptom but mild, '3' means they had that symptom moderately, '5' means they had that symptom severely. And let the respondents answer to DSOM(DSOM-Ⅱ for the rest) again. Finally, we investigated the correspondent rates of diagnosis between DSOM-Ⅰ,Ⅱ and doctors'. We obtained conclusions as following. In the comparison of output frequency rate of the pathogenic factors, the difference between DSOM-Ⅰ and Ⅱ was 1%. In the correspondent rates of diagnosis between DSOM-Ⅰ,Ⅱ and doctors', In DSOM-Ⅰ and Ⅱ answered by subjects two times respectively, the correspondent rate was highest in insufficiency of Yang(陽虛) and liver(肝) as 93.2%, lowest in damp(濕) as 69.5% and showed 81.9% in all 16 pathogenic factors mean. In DSOM-Ⅰ and Ⅱ, and Doctors' diagnose, they showed the complete correspondent rates of 15.3${\sim}$61.0%, 15.3${\sim}$59.3% in individual pathogenic factor, 36.5%, 37.3% in all 16 pathogenic factors mean each, and within ${\pm}$1 errorrange, they showed the correspondent rates of 32.2${\sim}$93.2%, 35.6${\sim}$89.8% in individual pathogenic factor, 67.6%, 67.3% in all 16 pathogenic factors mean each, and within ${\pm}$2 error range, they showed the correspondent rates of 62.7${\sim}$98.3%, 71.2${\sim}$100% in individual pathogenic factor, 85.1 87.6%% in all 16 pathogenic factors mean each. In the correspondent rates of the severe case, In the cases that the Doctors' diagnostic score mean was over 3(the severity of disease is middle), there were deficiency of qi(氣虛), stagnation of qi(氣滯), blood stasis(血瘀), damp(濕), liver(肝), heart(心), spleen(脾) and they all showed the correspondent rates of over 60 except blood stasis(血瘀). In the cases that the weighed pathogenic factor was above 9, the correspondent rates were 50${\sim}$100%. deficiency of qi(氣虛), blood-deficiency(血虛), stagnation of qi(氣滯), blood stasis(血瘀), insufficiency of Yin(陽虛), insufficiency of Yang(陽虛), coldness(寒), heat (熱), damp(濕), dryness(燥), liver(肝), heart(心), spleen(脾), kidney(腎), phlegm(痰).

A Study on Knowledge and Disease Management of Tuberculosis by Themselves of Tuberculosis Patients Among the Middle and High School Students in Seoul. (서울시내 중고등학교 결핵이환학생에 대한 결핵관리실태 및 지식에 관한 조사연구)

  • Do Sung-Sook
    • Journal of Korean Public Health Nursing
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    • v.1 no.1
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    • pp.32-44
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    • 1987
  • The purpose of this survey was to find out the knowledge and the disease management of the Tuberculosis patients by themselves among the first grade middle and high school students in Seoul city during the period of June 15-July 19, 1986. Questionaires were used to collect the data and were analysed from answers of 188 students at the 113 schools. The results were as follows: 1. The ages of the students were distributed as follows: in middle school, 13 years old was $70.0\%$. 14 years old, $20.0\%$, and 15 years old, $6.7\%$. In high school, 16 years old was $66.5\%$, 17 years old, $18.4\%$, and 15 years old, $10.1\%$. 2. In X-ray mass examination by school, the rate of execution was $50.4\%$ in middle school and $96.7\%$ in high school, and in X-ray mass examination by student, it was $50.1\%$ in middle school and $97.3\%$ in high school. 3. The prevalence of Tuberculosis among the middle school students was $00.3\%$and high school students, $0.15\%$. 4. Of the total, $77.1\%$ of the respondents did not realized Tuberculosis bdore X-ray mass examination 5. The perfect cure rate of the respondents was $52.7\%$. 6. General characteristics of the respondents: a. The educational background was varied as follows: of the total $47.9\%$ of the fathers had the level of high school education and $37.2\%$ of the mothers had the level of middle school education. The educational background of the parents had no statistical significant to the medical cure rate of Tuberculosis. (P>0.05). b. The average monthly income of the family was as follows : above five hundred thousand won was $21.8\%$, three or four hundred thousand won was $22.9\%$, and below two hundred thousand won was $10.6\%$. The most frequent family size was 5-6 persons. $(59.6)\%$. 7. The actual situation of Tuberculosis control and the variables related to the treatment: a. $69.1\%$ of the respondents wanted mental support from their surroundings. $48.7\%$ of the respondents answered that their parents or the other family helped treatment as mental supporter, b. As a medical service, $53.2\%$ of the respondents were treated at Health Center, $38.8\%$ were treated at a hospital. A medical service was statistically significant to the medical cure (P<0.01). c. Family members of $61.7\%$ of the respondents had checked chest X-ray. A X-ray examination of family was statistically significant to the medical cure (P<0.005). d. $73.9\%$ of the respondents had taken the Anti-Tuberculosis-drugs regularly. Regular taking of Anti-Tuberculosis drugs was statistically significant to the medical cure (P<0.005). e. $89.4\%$ of the respondents had received a regular examination during the treatment. A regular examination was statistically significant to the medical cure (P<0.05). f. The period of perfect cure was that $50.0\%$ of the respondents took from half a year to one year, $25.2\%$ took below half a year and $16.2\%$ took from one year to one year and a half. g. The rate of the respondents who abhored to let anyone know their disease was $93.1\%$. 8. Knowledge related with Tuberculosis: a .$63.3\%$ of the respondents answered that Tuberculosis is a communiable disease. b. $89.9\%$ of the respondents answered that there is a preventive method of Tuberculosis. Among them, $28.4\%$ answered that it is B.C.G. vacination. c. $96.8\%$ of the respondents belived they can be cured perfectly. d. $42.4\%$ of the perfect curer answered that they had have permanent immunity of Tuberculosis. According to the results of above study, it is desired to be practiced X-ray mass examination to the total middle school students. Nurse teachers and the responsible persons who participated to the helping of disease management to the Tuberculosis patients must make an offer knowledge of Tuberculosis to the Tuberculosis patients. And also, it will be very helpful to the cure of Tuberculosis patients if they do their best and to have a mental supporter.

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Result of Radiation Therapy for the Lung Cancer (폐암의 방사선치료 결과)

  • Kim Joo-Young;Choi Myung-Sun;Suh Won-Hyck
    • Radiation Oncology Journal
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    • v.7 no.2
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    • pp.213-225
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    • 1989
  • An analysis has been made of two hundred seven patients who were treated at the department of Radiation Oncology of Korea University Hospital for lung cancer from January 1981 through December 1986. There were 137 patients of nonsmall cell carcinoma (137/207, 66%), 26 patients of small cell carcinoma (26/207, 12.5%) and 44 patients of unproven histology. By aims of treatment, there were 104 patients (104/207, 50%) treated for cure, 89 patients (89/207, 42.9%) for palliation and 14 patients treated postoperatively. In 22 out of 207 patients, chemotherapy was done with radiotherapy, 12 of which were patients with small cell carcinoma. Stage II patients were 49 (49/207, 23.6%), stage III patients were 157 (157/207, 75.8%) and one patient had an occult cancer The tumor was initial Iy measured by CAT scan and chest X-rays in the 165 (165/207, 79.7%) patients, among which 117 patients had tumor diameter more than 5cm and 48 patients less than 5cm. Radiation therapy was given with Cobalt 60 teletherapy unit and the treatment volume encompassed primary tumor and the mediastinum. For curative aim, daily tumor dose of 180 cGy was given up to the range of 5,400~6,120cGy/30~34F/6~7 week period and for palliative aim, daily tumor dose of 300 cGy was given up to the range of 3,600~4,500 cGy/12~15F/2~3 week period. Postoperatively, mediastinum was treated for total dose of 5,040 cGy/28F/5.5 week period. 123 patients (123/207, 59%) were followed up after completion of radiotherapy for 14 months to 7 years. Local tumor response to the irradiation was measured by chest X-ray taken at one month follow up and was evaluated for response rate, if they were regressed more than 50% or less than 50% of the initial tumor size. The treatment results were as follows; 1. The median survival time was 8.5 months and survival rates for 1 year, 2 year and 5 year was 25%, 3.5% and 1% of nonsmall cell lung ca of 74 evaluable patients. 2. More than 50% of local tumor response rate was obtained in about half of overall cases; 90.5% for small cell ca, 50% for squamous cell ca, 25% for adenoca and 57% for large cell ca. 3. Response rate more than 50% was seen in the 50% of the patient group with tumor diameter more than 5cm and in the 55% of those with tumor diameter less than 5cm. 4. By total raidation dose given, patient group which was given 5,400~6,120 cGy equivalent dose or higher showed tumor response rate more than 50% in 53% of the patients, whereas the group with dose less than 5,400cGy equivalent, in 25% of the patients. 5. Survival rate for 6 month, 1 year and 2 year was compared between the group of local tumor response rate more than 50% vs. group with response rate less than 50%; 74% vs. 43%, 33% vs, 23%, 10% vs. 1%, respectively. 6. Local failure was seen in 21%(44/207) of the patients, which occured mostly within 15 months after completion of radiation therapy. Distant metastases were seen in 49.7%(103/207) of the patients, of which 43 cases were found before initiation of radiotherapy. The most common metastatic sites were bone and brain. In this sutdy, 1 year,2 year and S year survival rates were somewhat poor compared to the other studies. It mainly seems to be due to the poor general status of the patients and the far-advanced stage of the disease. In nonsmall cell cancer patients who had limited local disease and had small primary tumor size, we observed better local response. In addition, dose higher than 6,000 cGy group showed better tumor control than lower dose group. Survival rate was better for the local control group. For imporvement of local control of the lung cancer and hence, the survival of the patients with lung cancer, proper radical radiotherapy with high dose for localized disease is needed. New modality of treatment such as high LET beam in radiation therapy or drugs for the advanced disease as well as early diagnosis is also needed.

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Changes in Teaching Practices of Elementary School Teachers in Scientific Modeling Classes: Focused on Modeling Pedagogical Content Knowledge (PCK) (과학 모델링 수업에서 나타난 초등 교사의 수업 실행 변화 -모델링 PCK를 중심으로-)

  • Uhm, Janghee;Kim, Heui-Baik
    • Journal of The Korean Association For Science Education
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    • v.40 no.5
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    • pp.543-563
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    • 2020
  • This study explores how the teaching practices of two teachers changed during scientific modeling classes. It also aims to understand these changes in terms of the teachers' modeling pedagogical content knowledge (PCK) development. The study participants were two elementary school teachers and their fifth-grade students. The teachers taught eight lessons of scientific modeling classes about the human body. The data analysis was conducted for lessons 1-2 and 7-8, which best showed the change in teaching practice. The two teachers' teaching practices were analyzed in terms of feedback frequency, feedback content, and the time allocated for each stage of model generation, evaluation, and modification. Teacher A led the evaluation and modification stages in a teacher-driven way throughout the classes. In terms of feedback, teacher A mainly used answer evaluation feedback in lesson 1-2; however, in lesson 7-8, the feedback content changed to thought-provoking feedback. Meanwhile, teacher B mostly led a teacher-driven model evaluation and modification in lesson 1-2; however, in lesson 7-8, she let her students lead the model evaluation and modification stages and helped them develop models through various feedbacks. The analysis shows that these teaching changes were related to the development of modeling PCK components. Furthermore, the two teachers' modeling PCK differed in teaching orientation, in understanding the modeling stages, and in recognizing the value of modeling, suggesting the importance of these in modeling teaching practice. This study can help improve the understanding of modeling classes by revealing the relationship between teaching practices and modeling PCK.