• Title/Summary/Keyword: Performing confidence

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Treatment Outcomes of Percutaneous Radiofrequency Ablation for Hepatocellular Carcinomas: Effects of the Electrode Type and Placement Method

  • Jiyeon Park;Min Woo Lee;Soo Hyun Ahn;Seungchul Han;Ji Hye Min;Dong Ik Cha;Kyoung Doo Song;Tae Wook Kang;Hyunchul Rhim
    • Korean Journal of Radiology
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    • v.24 no.8
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    • pp.761-771
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    • 2023
  • Objective: To investigate the association among the electrode placement method, electrode type, and local tumor progression (LTP) following percutaneous radiofrequency ablation (RFA) for small hepatocellular carcinomas (HCCs) and to assess the risk factors for LTP. Materials and Methods: In this retrospective study, we enrolled 211 patients, including 150 males and 61 females, who had undergone ultrasound-guided RFA for a single HCC < 3 cm. Patients were divided into four combination groups of the electrode type and placement method: 1) tumor-puncturing with an internally cooled tip (ICT), 2) tumor-puncturing with an internally cooled wet tip (ICWT), 3) no-touch with ICT, and 4) no-touch with ICWT. Univariable and multivariable Cox proportional-hazards regression analyses were performed to evaluate the risk factors for LTP. The major RFA-related complications were assessed. Results: Overall, 83, 34, 80, and 14 patients were included in the ICT, ICWT, no-touch with ICT, and no-touch with ICWT groups, respectively. The cumulative LTP rates differed significantly among the four groups. Compared to tumor puncturing with ICT, tumor puncturing with ICWT was associated with a lower LTP risk (adjusted hazard ratio [aHR] = 0.11, 95% confidence interval [CI] = 0-0.88, P = 0.034). However, the cumulative LTP rate did not differ significantly between tumor-puncturing with ICT and no-touch RFA with ICT (aHR = 0.34, 95% CI = 0.03-1.62, P = 0.188) or ICWT (aHR = 0.28, 95% CI = 0-2.28, P = 0.294). An insufficient ablative margin was a risk factor for LTP (aHR = 6.13, 95% CI = 1.41-22.49, P = 0.019). The major complication rates were 1.2%, 0%, 2.5%, and 21.4% in the ICT, ICWT, no-touch with ICT, and no-touch with ICWT groups, respectively. Conclusion: ICWT was associated with a lower LTP rate compared to ICT when performing tumor-puncturing RFA. An insufficient ablation margin was a risk factor for LTP.

Associations of chronotype and insomnia with menstrual problems in newly employed nurses at university hospitals in the Republic of Korea

  • Han-Na Jung;Dongwhan Suh;Woo Chul Jeong;Jia Ryu;Yu-Mi Kim;Seohyun Yoon;Hyunjoo Kim
    • Annals of Occupational and Environmental Medicine
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    • v.35
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    • pp.30.1-30.13
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    • 2023
  • Background: Dysmenorrhea and menstrual cycle changes occur in women working shifts. Circadian rhythm disruption and sleep disturbances associated with shift work leads to health problems. We identified chronotypes and the occurrence of insomnia among newly employed university hospital nurses and investigated the association of these factors with menstrual problems. Methods: We conducted pre-placement health examinations for shift workers using self-reported questionnaires between 2018 and 2020. A total of 463 nurses were included in the study. Sociodemographic data, shift work experience, and information on insomnia were collected from health examination data. In addition, details regarding chronotype, dysmenorrhea, irregular and abnormal menstrual cycles, amenorrhea, and contraceptive use were obtained from the questionnaire. Multiple logistic regression analysis was performed to study the association between chronotype, insomnia, and menstrual problems after controlling for age, body mass index, contraceptive use, amenorrhea, and prior shift work. Results: The prevalence rates of dysmenorrhea, irregular menstrual cycles, and longer menstrual cycles were 23.8%, 14.9%, and 4.1%, respectively. The risk of dysmenorrhea increased in the evening-type (odds ratio [OR]: 3.209; 95% confidence interval [CI]: 1.685-6.113) and those with insomnia (OR: 1.871; 95% CI: 1.074-3.261). Additionally, the risk of an irregular menstrual cycle (OR: 2.698; 95% CI: 1.167-6.237) increased in the evening-type, and the risk of a longer menstrual cycle (OR: 4.008; 95% CI: 1.354-11.864) increased in individuals with insomnia. Conclusions: Our findings suggest that dysmenorrhea is promoted in the evening-type and insomnia individuals. There may be an increased risk of irregular menstrual cycles among evening-type nurses and an increased risk of longer menstrual cycles among those with insomnia. Therefore, factors such as evening-type and insomnia should be considered for the prevention of menstrual problems in women performing shift work.

Early Aortic Valve Replacement in Symptomatic Normal-Flow, Low-Gradient Severe Aortic Stenosis: A Propensity Score-Matched Retrospective Cohort Study

  • Kyu Kim;Iksung Cho;Kyu-Yong Ko;Seung-Hyun Lee;Sak Lee;Geu-Ru Hong;Jong-Won Ha;Chi Young Shim
    • Korean Circulation Journal
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    • v.53 no.11
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    • pp.744-755
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    • 2023
  • Background and Objectives: Aortic valve replacement (AVR) is considered a class I indication for symptomatic severe aortic stenosis (AS). However, there is little evidence regarding the potential benefits of early AVR in symptomatic patients diagnosed with normal-flow, low-gradient (NFLG) severe AS. Methods: Two-hundred eighty-one patients diagnosed with symptomatic NFLG severe AS (stroke volume index ≥35 mL/m2, mean transaortic pressure gradient <40 mmHg, peak transaortic velocity <4 m/s, and aortic valve area <1.0 cm2) between January 2010 and December 2020 were included in this retrospective study. After performing 1:1 propensity score matching, 121 patients aged 75.1±9.8 years (including 63 women) who underwent early AVR within 3 months after index echocardiography, were compared with 121 patients who received conservative care. The primary outcome was a composite of all-cause death and heart failure (HF) hospitalization. Results: During a median follow-up of 21.9 months, 48 primary outcomes (18 in the early AVR group and 30 in the conservative care group) occurred. The early AVR group demonstrated a significantly lower incidence of primary outcomes (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.29-0.93; p=0.028); specifically, there was no significant difference in all-cause death (HR, 0.51; 95% CI, 0.23-1.16; p=0.110), although the early AVR group showed a significantly lower incidence of hospitalization for HF (HR, 0.43; 95% CI, 0.19-0.95, p=0.037). Subgroup analyses supported the main findings. Conclusions: An early AVR strategy may be beneficial in reducing the risk of a composite outcome of death or hospitalization for HF in symptomatic patients with NFLG severe AS. Future randomized studies are required to validate and confirm our findings.

Measurement of competency through self study in basic nursing lab. practice focused on cleansing enema (기본간호학 실습에 있어 자가학습을 통한 능숙도 측정 - 배변관장을 중심으로 -)

  • Ko Il-Sun
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.6 no.3
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    • pp.532-543
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    • 1999
  • This study was conducted to provide the basic data necessary for the improvement of the teaching method for basic nursing practice as well as the effectiveness of the practice by examining the students' competency in cleansing enema after doing the self study instead of the traditional education. To examine the competency in cleansing enema after the self study, this study is an one group pretest-posttest design that subjects did the enema practice through the self study. The subjects were 89 sophomore students at Y University. College of Nursing. In basic nursing lab practice class, cleansing enema self study module was given to the students which was developed by the researcher based on the literature review and asked them to finish doing the pre study and checking the self study evaluation criteria after reading the goal, learning activities and theoretical guideline. After watching the video tape, students practiced the process in the module by themselves. For the competency in cleansing enema. repeated autonomous practices were done during the open lab other than the regular class. Whenever the practice was done, the frequency and time were measure and documented. When the student felt confident through repeated practices, the competency was evaluated by the researcher and two assistants based on the evaluation criteria. And the process was repeated till the student could perform all the items on evaluation criteria completely. The data were collected for 42 days from Oct. 15 to Nov. 26 in 1996. Collected data were analyzed by frequency, percentage, Pearson correlation coefficient and variance analysis. The results are summarized as follows : 1. 43.2% of the students were favorable to nursing and 63.6% like lecture, but 71.6% like practice. So they were more interested in practice than in lecture. 2. 62.3% of the students scored high in written test, 97.8% scored high in practice. So the practice score was better. 3. The frequency of repeated practice to pass the test ranged from 1 to 4 and the average is 2.2. 4. The average time needed in preparation and the performance was nearly the same regardless of the frequency. It took 5 to 38 minutes for those who passed the test after practicing once and the average was 16 minutes. 5 to 60 minutes were taken for those who practiced twice to pass the test and the average was 21 minutes. Those who passed the test after three practices needed 8 to 30 minutes and the average was 15 minutes, which was similar to the time that the students who passed the test for the first trial. Only one student passed the test after 4 practices and it took 10 minutes. 5. 64% of the students agreed that the context and the content of the module were appropriate for the self study and 68.2% were satisfied. And 71.9% said that the module helped them to practice the enema self study 6. Though only 42% of the students were satisfied with the video. 50.6% said that it was helpful for the self study. 7. 52.3% of the students were satisfied with the self study method, and 86.6% obtained self-confidence when performing the enema. 8. The lower the student's practice score was, the more practices were needed for them to pass the test(r=-.213, P<.05). As a result, for performing the enema practice competently, two or more practice opportunities were needed to be given. And it is possible to obtain the less complex nursing skills through the self study, when enough learning resources and assistance such as learning guidance or video tapes are provided. Based on this study. I want to suggest that. 1. There must be college policy that can support the new method instead of the traditional learning method for the students to attain the proficiency in basic nursing skills. 2. The assistant materials should be developed as soon as possible to promote the self study of basic nursing skills.

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A Study on the Effective Independent Study of Nursing Student (간호학생의 효과적인 자율학습을 위한 조사연구)

  • 김광주;이향련
    • Journal of Korean Academy of Nursing
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    • v.8 no.1
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    • pp.16-42
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    • 1978
  • This survey was made for a month starting from November 15 to December 15, 1977 covering 711 students taking the junior. (3rd-yea.) and the senior. (4th-year) at nine college of nursing in Seoul concerning their perception and Attitude toward the profession of nursing, motive for the necessity of learning, environment of study, attitude of study and particulars relevant with study performance, particulars of library, references and reading, assignments and particulars of the degree of confidence for the learning achievement. Through the survey of the above Particulars, the following results were obtained by classifying all subject matters and by analysing motive of the selection of their course, awarding or not awarding of scholarships. 1. General characteristics: it was revealed that 406 students (57.1%) were attending at the junior. while 305 students (42.9%) were taking the senior. Thus, the total number was 711 and their average age was 21.4 years. Their dwelling category was; 73.9 percent of them resided at their parent's home, 214 students (30.1%) were awarded with scholarships. The reason to be attracted by nursing science was the possibility of continuing social life after graduation (43.5%). 2. Their perception and attitude toward the profession of nursing: According to the perception of profession by the students of each grade, students of the 4th grade showed comparatively strong conception. Also, students of the 4th grade showed more positive attitude in the purchase and reading of magazines relative with the science of nursing, in the reading of Code for Nurses and in their interest in the activity of nursing field. For the necessity of mission of nurse, 97.7 percent of the entire number of students covered responded to necessity. For the necessity of the particular humanity and particularity in the character of nurses, 95.8 percent of those students responded to necessity. By the each grade, students of the 4th grade showed more response. 3. As to professional field desired after completing the professional course: 57 percent of those students desired for clinician nurse while 55 percents desired for community health-nurse. 4. As to the environment of study: they were mostly satisfied with their present residential environment. However, they complained of inconvenience at their lecture-halls. Students of the 3rd grade showed more complain. As to their attitude toward the adjustment of environment of study, they showed a affirmative response. As to the opinion of factors which interfere with their study, comparatively strong response was showed in their scepticism in the science of nursing, insufficient comprehension in general learning, relation with professors n4 discrepancy in the method of study. According to opinions of students at each grade, students of the 4th grade showed more scepticism. 5. Particulars relative with their attitude and performance of study : As to their knowledge of the objectives of their study of subject, the majority was to study with a partial knowledge of the objectives of their study. As to the plan of study, a low percentage indicated management of routine life under regular scheduling. Students of the 4th grade responded to rather planned life. As to time spent in independent study, response to concentrated study when necessary was stronger than that to regular daily study. Students of the 4th grade showed stronger response to regular study than that of the 3rd grade. As to the contents of their note-taking, 67.4 percents of those students responded to such regulatory procedure performing in the lecture-hall as they listen to lectures. 17.3 percents of those students showed response to adding supplementary informations from references to what was entered in choir note-taking at their lecture-halls. 6. Particulars of library, references and reading books: As to receiving of instruction for the utilization of library and time of receiving such instruction 64.7 percents of those students had received such instruction. 66.7 percents of the those responded received such instruction at orientation conducted for freshmen. As to the convenience of the utilization of library, 49.9 percents of those students responded to convenience. However, students of the 3rd grade showed a much stronger response to inconvenience. As to the time of the utilization of library,92.5 percents of those students showed a response to occasional utilization for particular purpose than regular utilization. 53.2 percents of those students responded to ordinary in quantity that library have references. 34.2 percents of those students responded to insufficient. As to the particular relative with the method and field of reading: 53.5 percents of those students responded to intensive reading and was the majority. As to the reading field, fiction u as the majority. When read any books for their major, they usually rend Korean text-b, oks. 7. Particular relative with giving assignment: All respondents were well aware of the objectives of giving home tasks. As to the attitude toward assignments and performing home tasks, 54.8 percents of those students to making ostentatious study because of an excessive quantity of assignments imposed. For performing assignment, they showed comparatively positive response. Also, 52.2 percents of those students responded that they usually submitted complected assignment with references. 8. As to motive to realize the necessity of study : 55.6 percents of those students responded that they realized such necessity in communication with patients when they were engaged in clinical practice. Also, 8.6, the lowest percents of those students responded that they realized such necessity in the course of conversation with nurses when they were engaged in clinical practice. 9. As to the determination of their confidence in the performance of study relative with clinical experience: They showed a general inclination of having in nursing. The major response was that they came to well comprehend the patients families. the lowest response was that they could apply what was learned at lecture-hall to practice. This response incidentally showed the distance the lecture-hall and practical study. In general items, students of the 4th grade showed more favorable response than students of the 3rd grade and there was a significant difference. 10. As to the perception and attitude toward profession according to the motive of selecting the nursing science : Those who selected the nursing voluntarily showed stronger conception than those who selected the nursing through indirect influence. However, there was no significant difference on this point. Only there was a remarkable difference in the reading of Code for Nurses. 11. Those who showed a stronger conception in the profession of nursing according to the motives of attractive nursing science indicated a strong will and ability to manage stable life and comparatively strong response was shown in the management of good home life because of the good adaptability of the science to their character. This group showed a strong conception of the profession than those who responded that they prefer this profession out of a longing for the work of a hospital and for the easy obtaining of opportunity to immigrate to over seas and for economic cause and for high school grade. There was significant difference between these two groups, 12. As to the conception and attitude toward the profession of nursing according to benefits by scholarships, those who were benefitted by scholarship showed stronger conception of profession than those who did not receive scholarship and there was a remarkable difference between these two categories. However, there was no remarkable difference between these two categories in the extent of interest of the activities of nursing fields and in the reading of Code for Nurses. 13. As activation for study according to the benefits of scholarships, those who were benefitted by scholarships showed stronger response to the motive for study comparing with those who receive. 14. As to tile field of reading according to the benefits by scholarships, those who received scholarships tended to read autobiographies and essayers to a considerable extent. Those who did not receive scholarships tended to read novels. Those who received scholarships more read nursing boots than those who did not receive scholarships. 15. As to the attitude of study and doing of assignment according to benefits of scholarships, those who received scholarships managed a favorable life with schedules for study, More students of receiving scholarship showed a regular study for more than one hour per day. Also, in the method of doing home tasks, more students of receiving scholarship showed reference to relative books frequently for the submission of completed assignments.

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A Study of School Nursing Activity Performed by School Nurses and Teachers Holding Additional School Health (부산지역 중등학교 양호교사 및 양호겸직교사의 학교보건업무 활동 양상)

  • Park Jung Za;Jung Moon Sook
    • Journal of Korean Public Health Nursing
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    • v.9 no.1
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    • pp.17-32
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    • 1995
  • The purpose of this study was to improve upon school health by understanding the present status of school health and escpecially to investigate the performance rate of regular health instruction. 261 schools, including middle and high schools enrolled in the Busan Educational Association, were sent Questionnaires. Data was collected from the 25th of January to the 10th of April, 1994. 229 subjects who responded to the Questionnaires were finally analyzed as samples. Among them, 127 were school nurses and 102 were teachers acting in a school health capacity. The results of this study are summerized as follows: Of the teachers holding additional school health responsibilities, $85.6\%$ worked in private schools. Many of them $(74.5\%)$ were formally dissatisfied with their ability to provide care because $85.3\%$ of them had never studied any school health. Some of them$(30.4\%)$ didn't know about the annual school nursing budget and $23.5\%$ of them hadn't taught any health education to students. In spite of this fact, they were placed in charge of a school health activity against their own will. There were statistically significant differences in the performance of school health affairs between nurses and teachers holding additional school health (p<0.001) as follows: annual school nursing budget, Health Program Planning and Evaluation, annual purchase price for medicines, average students cared for per day, average students who held at least one consultation per month and extra. Surely, the self-confidence of school nurses was higher than that of teachers with school health as an assigned responsibility. This was demonstrated by a significant statistical difference (p<0.01) in the responses by the two groups. $88.2\%$ of the school nurses and $73.5\%$ of teachers for school health thought that regular health instruction was necessary. But regular health education had been performed only by $32.8\%$ of respondents. Among them, 84% were school nurses and $16\%$ were teachers holding additional school health. Of the persons who performed regular health education, $69.3\%$ used less than $60\%$ of the health content of the athletic textbook. And $64\%$ of them said teaching materials were insufficient. Most of them $(69.4\%)$used home made lesson plans. which they compiled from various sources. There was a significant difference in the formality of the health lesson according to the concern of the school principal (p<0.01) and there was a significant difference in performing health education between school nurses and teachers holding additional school health (p<0.001) It appears that there are a lot of problems with providing school health care using people who are untrained. In a word, school health nurses with professional training are needed in order to perform the qualitative management for the health of the students. These days, regular health education is an indispensable part in making students improve their self-care abilities. Therefore a more effective and better defined program should be prepared for regular systematic health education. To resolve these problems, present laws and regulations related to school health should be revised considering the specialist's request for the improvement of school health. In addition, the concern and financial support of the government are essential.

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Association of Cytotoxic T-lymphocyte Antigen-4 Polymorphisms with Malignant Bone Tumors Risk: A Meta-analysis

  • Zhang, Chao;Hou, Wei-Hua;Ding, Xuan-Xi;Wang, Xiong;Zhao, Hui;Han, Xing-Wen;Wang, Wen-Ji
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.8
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    • pp.3785-3791
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    • 2016
  • Background: Previous studies have assessed the association between the Cytotoxic T-lymphocyte Antigen-4(CTLA-4) polymorphism with the risk of malignant bone tumor, but the conclusions were inconsistent. We aimed to clarify association of cytotoxic T-lymphocyte antigen-4 polymorphisms with malignant bone tumors risk by performing a meta-analysis. Materials and Methods: The databases including PubMed, EMBase databases and the Cochrane Library were searched to identify the eligible studies prior to January 30 2016. Odds ratio (OR) with 95% confidence interval (95%CI) were used to estimate the strengths of the association between the CTLA-4 polymorphism and the malignant bone tumor risks. The meta-analysis was performed by STATA 12.0. Results: Four individual studies with a total of 1003 cases with malignant bone tumor and 1162 controls were included in our meta-analysis. The results of meta-analysis on those data demonstrated that CTLA-4 +49G>A polymorphism was associated with the risk of Ewing's sarcoma and osteosarcoma strongly (A vs. G: OR=1.36, 95%CI:1.20-1.54, p=0.000; AA+AG vs. GG: OR=1.35, 95%CI:1.14-1.61, p=0.001; AA vs. GG: OR=2.24, 95%CI:1.67-2.99, p=0.000; AA vs. AG+GG: OR=2.00, 95%CI:1.53-2.62, p=0.000), but CTLA-4 -318C/T polymorphism was not associated with the risk of malignant bone tumor (C vs. T: OR=0.76, 95%CI:0.76-1.08, p= 0.262; CC+CT vs. TT: OR=0.70, 95%CI:0.41-1.20, p= 0.198; CC vs. TT: OR=0.69, 95%CI:0.40-1.19, p= 0.183; CC vs. CT+TT: OR=0.92, 95%CI:0.75-1.13, p= 0.419). Subgroup analysis showed that there are significantly positive correlations between CTLA-4 +49G>A polymorphism and increased risks of malignant bone tumors in large size of sample (A vs. G: OR=1.347, 95%CI: 1.172,1.548, p=0.000; AA vs. GG: OR=2.228, 95%CI: 1.608,3.085, p=0.000), Ewing's Sarcoma or Osteosarcoma (A vs. G: OR=1.361, 95%CI: 1.201,1.540, p=0.000; AA vs. GG: OR=2.236, 95%CI: 1.674,2.986, p=0.000), and PCR-RFLP or Sequencing(A vs. G: OR=1.361, 95%CI: 1.201,1.540, p=0.000; AA vs. GG: OR=2.236, 95%CI: 1.674,2.986, p=0.000), but CTLA-4 -318C/T polymorphism was not associated with the risk of malignant bone tumors in diagnosis, genotype method, and sample size (all p>0.05). Conclusions: CTLA-4 +49A/G variant was associated with an increased risk of developing the malignant bone tumors, such as Ewing's sarcoma and osteosarcoma. However, it failed to show the association between CTLA-4 -318C/T polymorphism and the risk of malignant bone tumors. Future large-scale studies remain to be done to confirm our conclusions.

Accurate Quality Control Method of Bone Mineral Density Measurement -Focus on Dual Energy X-ray Absorptiometry- (골밀도 측정의 정확한 정도관리방법 -이중 에너지 방사선 흡수법을 중심으로-)

  • Kim, Ho-Sung;Dong, Kyung-Rae;Ryu, Young-Hwan
    • Journal of radiological science and technology
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    • v.32 no.4
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    • pp.361-370
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    • 2009
  • The image quality management of bone mineral density is the responsibility and duty of radiologists who carry out examinations. However, inaccurate conclusions due to lack of understanding and ignorance regarding the methodology of image quality management can be a fatal error to the patient. Therefore, objective of this paper is to understand proper image quality management and enumerate methods for examiners and patients, thereby ensuring the reliability of bone mineral density exams. The accuracy and precision of bone mineral density measurements must be at the highest level so that actual biological changes can be detected with even slight changes in bone mineral density. Accuracy and precision should be continuously preserved for image quality of machines. Those factors will contribute to ensure the reliability in bone mineral density exams. Proper equipment management or control methods are set with correcting equipment each morning and after image quality management, a phantom, recommended from the manufacturer, is used for ten to twenty-five measurements in search of a mean value with a permissible range of ${\pm}1.5%$ set as standard. There needs to be daily measurement inspections on the phantom or at least inspections three times a week in order to confirm the existence or nonexistence of changes in values in actual bone mineral density. in addition, bone mineral density measurements were evaluated and recorded following the rules of Shewhart control chart. This type of management has to be conducted for the installation and movement of equipment. For the management methods of inspectors, evaluation of the measurement precision was conducted by testing the reproducibility of the exact same figures without any real biological changes occurring during reinspection. Bone mineral density inspection was applied as the measurement method for patients either taking two measurements thirty times or three measurements fifteen times. An important point when taking measurements was after a measurement whether it was the second or third examination, it was required to descend from the table and then reascend. With a 95% confidence level, the precision error produced from the measurement bone mineral figures came to 2.77 times the minimum of the biological bone mineral density change. The value produced can be stated as the least significant change (LSC) and in the case the value is greater, it can be stated as a section of genuine biological change. From the initial inspection to equipment moving and shifter, management must be carried out and continued in order to achieve the effects. The enforcement of proper quality control of radiologists performing bone mineral density inspections which brings about the durability extensions of equipment and accurate results of calculations will help the assurance of reliable inspections.

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A Study on Spatial Pattern of Impact Area of Intersection Using Digital Tachograph Data and Traffic Assignment Model (차량 운행기록정보와 통행배정 모형을 이용한 교차로 영향권의 공간적 패턴에 관한 연구)

  • PARK, Seungjun;HONG, Kiman;KIM, Taegyun;SEO, Hyeon;CHO, Joong Rae;HONG, Young Suk
    • Journal of Korean Society of Transportation
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    • v.36 no.2
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    • pp.155-168
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    • 2018
  • In this study, we studied the directional pattern of entering the intersection from the intersection upstream link prior to predicting short future (such as 5 or 10 minutes) intersection direction traffic volume on the interrupted flow, and examined the possibility of traffic volume prediction using traffic assignment model. The analysis method of this study is to investigate the similarity of patterns by performing cluster analysis with the ratio of traffic volume by intersection direction divided by 2 hours using taxi DTG (Digital Tachograph) data (1 week). Also, for linking with the result of the traffic assignment model, this study compares the impact area of 5 minutes or 10 minutes from the center of the intersection with the analysis result of taxi DTG data. To do this, we have developed an algorithm to set the impact area of intersection, using the taxi DTG data and traffic assignment model. As a result of the analysis, the intersection entry pattern of the taxi is grouped into 12, and the Cubic Clustering Criterion indicating the confidence level of clustering is 6.92. As a result of correlation analysis with the impact area of the traffic assignment model, the correlation coefficient for the impact area of 5 minutes was analyzed as 0.86, and significant results were obtained. However, it was analyzed that the correlation coefficient is slightly lowered to 0.69 in the impact area of 10 minutes from the center of the intersection, but this was due to insufficient accuracy of O/D (Origin/Destination) travel and network data. In future, if accuracy of traffic network and accuracy of O/D traffic by time are improved, it is expected that it will be able to utilize traffic volume data calculated from traffic assignment model when controlling traffic signals at intersections.

Exploring the Agency of a Student Leader in Collaborative Scientific Modeling Classes in an Elementary School (초등학교의 협력적 과학 모델링 수업에서 나타난 리더의 행위주체성 탐색)

  • Uhm, Janghee;Kim, Heui-Baik
    • Journal of The Korean Association For Science Education
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    • v.41 no.4
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    • pp.339-358
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    • 2021
  • This study explores the agency of a student leader, expressed through efforts to distribute power and encourage participation in elementary scientific modeling classes. The study also analyzes the context in which the leader's agency was expressed and the context in which the development of a collective agency was constrained. The participants were 22 fifth-grade students. The leader's agency was analyzed by examining his words and actions. As a result, at the outset of the study, the leader had the most power, performing all the activities as the sole authority in a non-cooperative participation pattern. However, with reflection and help from the researcher, the leader recognized the problem and facilitated the participation of other students. He developed an identity as a teacher and demonstrated the agency. The leader's agentic behaviors can be categorized into three aspects. First, regarding the cognitive aspect, the leader helped other students participate in modeling by sharing his knowledge. Second, regarding the normative aspect, he made rules to give all students an equal voice. Third, regarding the emotional aspect, the leader acknowledged the contribution of the students, increasing their confidence. The leader's agency temporarily helped the group to overcome the student hierarchy, facilitating a cooperative participation pattern. However, the development of a collective agency was constrained. The power of the leader was partially redistributed, and the other students did not position themselves as equal to the leader. To support the leader's agency to develop into a collective agency, it is necessary to redistribute the power of the leader more equally and to change the recognition of students.