• 제목/요약/키워드: Difficulty analysis

검색결과 2,557건 처리시간 0.03초

광픽업용 비구면 렌즈 사출성형 공정의 수치해석 (Numerical Analysis for the Injection Molding of an Aspheric Lens for a Photo Pick-up Device)

  • 박근;한철엽
    • 한국정밀공학회지
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    • 제21권11호
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    • pp.163-170
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    • 2004
  • In order to produce high-quality optical components, aspheric lenses have been widely applied in recent years. An aspheric lens consists of aspheric surfaces instead of spherical ones, which causes difficulty in the design process as well as the manufacturing procedure. Although injection molding is widely used to fabricate optical lenses owing to its high productivity, there remains lots of difficulty to determine appropriate mold design factors and injection molding parameters. In the injection molding fields, computer simulation has been effectively applied to analyze processes based on the shell analysis so far. Considering the geometry of optical lenses, however, numerical analysis based on solid elements has been reported as more reliable approach than shell -based one. The present work covers three-dimensional injection molding simulation using MP1/Flow3D and relevant deformation analysis of an injection molded plastic lens based on solid elements. Numerical analysis has been applied to the injection molding processes of an aspheric lens for a photo pick-up device. The reliability of the proposed approach has been verified in comparison with the experiments.

한국 노인의 보철 필요 상태에 따른 저작불편 조사 (Current chewing difficulty according to dental prosthesis needs in Korean elderly)

  • 김태헌;진혜정
    • 한국산학기술학회논문지
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    • 제15권7호
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    • pp.4353-4360
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    • 2014
  • 이 연구는 우리나라 노인의 구강건강 개선을 위하여 현재 저작 불편 호소와 치과 보철 필요와의 관련성을 평가하고자 하였다. 연구대상자는 제5기 1차년도 국민건강영양조사에 참여한 65세 이상 노인 1,177명을 대상으로 조사를 실시하였다. 구강검사를 통하여 상실치아와 필요 보철 상태를 파악하였으며, 구조화된 설문도구를 이용하여 사회경제요인, 구강건강 관심도, 저작능력과 발음문제를 조사하였다. 수합된 자료는 SPSS 19.0 프로그램을 사용하여 분석하였다. 우리나라 노인의 42.9%는 저작 불편을 호소하였으며, 로지스틱 회귀분석을 통하여 혼란변수를 보정한 결과 고정 보철 필요 위험비는 1.22, 부분의치 필요 위험비는 2.47, 총의치 필요 위험비는 2.06이었다. 치과보철 필요는 저작 불편 호소와 관련이 있었다. 따라서 노인을 위한 치과 보철 정책과 구강건강증진의 뒷받침이 가장 필요하다.

수술실 간호사의 경력등급별 간호행위분석 (Nursing Action Analysis of Operation Room Nurse According to Their Career Ladders)

  • 채수정;안준희;김은혜;김효정
    • 임상간호연구
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    • 제18권1호
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    • pp.86-98
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    • 2012
  • Purpose: The present study was conducted with the aim of developing a training manual for operation room nurses through an examination of nursing actions in terms of the frequency of performance, importance, and the levels of difficulty. The participants were recruited from the five university-affiliated hospitals according to one's career ladders, resulting in getting 181 OR nurses enrolled. Methods: Researchers developed a questionnaire using a 5-point Likert scale which measuring OR nurses' actions, importance, and the levels of difficulty. The frequencies of performance, importance and the levels of difficulty of nursing action were compared according to their career ladders using one-way ANOVA. Results: The frequencies of performance showed significant differences in 26 items according to the participants' career ladders; the importance in 6 items; and the levels of difficulty in 19 items among the OR nurses' actions. Conclusion: Given the fact that the significant differences were shown in the frequencies of performance, importance, and the levels of difficulty in nursing action across differing work experience, continuous development and application of job training based on one's work experience seem crucial in practice.

기계학습 기반 비트코인 채굴 난이도 예측 연구 (Machine Learning Based Prediction of Bitcoin Mining Difficulty)

  • 이준원;권태경
    • 정보보호학회논문지
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    • 제29권1호
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    • pp.225-234
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    • 2019
  • 비트코인은 탈중앙화와 분산원장을 특징으로 하는 암호화폐로서 "작업증명"이라는 채굴시스템을 통해 유지된다. 채굴 시스템에서는 블록 생성시간을 일정하게 유지하기 위해 채굴 난이도를 조정하게 되는데, 기존의 채굴 난이도 변경 방식은 미래의 해시파워를 반영할 수 없다는 문제가 있다. 따라서 실제시간과 예정시간 사이에 발생하는 오차로 인해 블록생성과 실세계 시간의 불일치를 가중시키게 되고, 결국 거래 기한을 맞추지 못하거나 코인 호핑 공격에 취약점을 노출시키게 된다. 블록 생성시간을 일정하게 유지시키기 위한 기존 연구도 여전히 오차 문제를 갖는다. 본 연구에서는 이러한 오차를 줄이기 위한 기계학습 기반 채굴 난이도 예측 방안을 제시한다. 이전 해시파워를 학습하여 미래의 해시파워를 예측하고 예측한 값을 이용하여 채굴 난이도를 조정한다. 우리의 실험 결과는 이와 같은 경우 기존 채굴 난이도 조정방식보다 오차율을 약 36% 더 줄일 수 있음을 보여준다.

가족의례가 가족건강성에 미치는 영향 (The Effects of Family Rituals on Family Strengths)

  • 배재현
    • 한국콘텐츠학회논문지
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    • 제16권12호
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    • pp.622-635
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    • 2016
  • 본 연구는 가족의례의 종류에 따른 주요활동과 갈등요인들을 확인하고, 가족의례가 가족건강성에 미치는 영향을 살펴봄으로써 가족건강성을 높일 수 있는 실천적 함의를 제공하는 데 목적이 있다. 이를 위해 성인남녀 216명에게 설문조사하였고, 결과를 확인하기 위해 빈도분석, MANOVA, 중다회귀분석을 실시하였다. 주요 결과는 다음과 같다. 첫째, 가족식사의례의 주요활동은 '집에서 직접요리'가 가장 많았고, 갈등요인은 '일이 너무 바빠서'가 가장 많았다. 가족주말여가의례의 주요활동은 '근교나들이', 갈등요인은 '가족공동의 시간을 갖기 어려워서'가 제일 많았다. 가족생일의례의 주요활동은 '케익 준비하기', 갈등요인은 '내 생일을 가족이 잊어버려서'가 제일 많았다. 결혼기념일의례의 주요활동은 여성의 경우 '외식하기', 남성의 경우 '꽃이나 선물주기', 갈등요인은 여성의 경우 '배우자가 결혼기념일을 잊어버려서', 남성의 경우 '내가 원하는 축하방식이 아니어서'가 제일 많았다. 명절의례의 갈등요인은 여성의 경우 '배우자가 나의 어려움을 이해해주지 못하는 것 같아서', 남성의 경우 '친척들과의 인간관계 문제'가 제일 많았다. 둘째, 연령에 따라 가족의례에 통계적으로 유의한 차이가 있는 것으로 나타났다. 셋째, 가족의례는 가족건강성에 통계적으로 유의한 영향을 미치는 것으로 나타났다.

보건소 맞춤형 방문건강관리사업 전문인력의 직무분석 (Task Analysis of Managers in the Customized Visiting Health Services)

  • 한영란;박영례;김영희;최희정;정미자
    • 지역사회간호학회지
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    • 제23권2호
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    • pp.165-178
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    • 2012
  • Purpose: The aim of this study was to analyze the tasks of managers who were working in the Customized Visiting Health Services (CVHS) and to prioritize analyzed tasks according to performance frequency, perceived importance, and difficulty. Methods: Job analysis method by Hartley (1999) was used for task analysis and performance frequency, perceived importance, and difficulty were used for prioritize as criteria. A total of 85 managers in the CVHS of public health centers nationwide were recruited through e-mail and mail survey. Using SPSS/WIN 15.0, descriptive statistics, such as frequency distribution, means, median, and standard deviation, were conducted to examine each subject's general characteristics, the frequency, importance, and difficulty of the tasks as well as to prioritize the each task. Results: The job description of the managers revealed 12 duties, 35 tasks, and 104 task elements. Of the 85 managers, 84.8% were classified as nurses, 40.5% were home health care specialists, and 32.9% were social workers. Their coretasks were management of client cases, budget management, and management of work performance and quality assurance. Conclusion: Considering the analyzed managers' tasks and core tasks, we need to examine each manager's role precisely and provide various educational programs for improving overall manager competence.

문항반응이론을 활용한 한의학 교육에서 본초학 시험문항에 대한 연구 (Study on the herbology test items in Korean medicine education using Item Response Theory)

  • 채한;한상윤;양기영;김형우
    • 대한본초학회지
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    • 제37권2호
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    • pp.13-21
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    • 2022
  • Objectives : The evaluation of academic achievement is pivotal for establishing accurate direction and adequate level of medical education. The purpose of this study was to firstly establish innovative item analysis technique of Item Response Theory (IRT) for analyzing multiple-choice test of herbology in the traditional Korean medicine education which has not been available for the difficulty of test theory and statistical calculation. Methods : The answers of 390 students (2012-2018) to the 14 item herbology test in college of Korean medicine were used for the item analysis. As for the multidimensional analysis of item characteristics, difficulty, discrimination, and guessing parameters along with item-total correlation and percentage of correct answer were calculated using Classical Test Theory (CTT) and IRT. Results : The validity parameters of strong and weak items were illustrated in multiple perspectives. There were 4 items with six acceptable index scores, and 5 items with only one acceptable index score. The item discrimination of IRT was found to have no significant correlation with difficulty and discrimination indices of CTT emphasizing attention of professionals of medical education as for the test credibility. Conclusion : The critical suggestions for the development, utilization and revision of test items in the e-learning and evidence-based Teaching era were made based on the results of item analysis using IRT. The current study would firstly provide foundation for upgrading the quality of Korean medicine education using test theory.

두 시기의 실측자료에 의한 산불 피해 정도 분석 (Analysis of Forest Fire Damage by Using Two Times series for Ground Truth Data)

  • 김동희;최승필;최철순;건석륙태랑
    • 한국측량학회:학술대회논문집
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    • 한국측량학회 2006년도 춘계학술발표회 논문집
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    • pp.139-144
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    • 2006
  • Forest fire is due to difficulty in approaching the forest fire at the time of forest fire and quite a long of time required for post-fire investigation, accurate analysis of damages to the forest area caused by forest fire is difficult to obtain. Recently, In attempt to overcome such difficulty, many researches are using satellite images. Nevertheless, it is not easy for everyone to obtain the satellite image data, and additional researches in order to verify accuracy of such data are also required. Therefore, in this study for satellite image to about damages to the forest areas caused by forest fire using tile selected two data of spectral reflectance of the vegetation, gained by using a spectrometer. That is we wished to search about mistake that is apt to happen by one time eyesight observation by analyzing two datas that is used spectral radiometer 3 months and 6 months later and gets.

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베트남 결혼이주여성의 한국 적응과정에서의 임신과 출산 경험 분석: 포커스 그룹 인터뷰 (Analysis on Pregnancy and Childbirth Experience of Vietnamese Marriage Migrant Women during Adaptation to Korea: Focus Group Interview)

  • 이선희
    • 부모자녀건강학회지
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    • 제20권1호
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    • pp.28-38
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    • 2017
  • Purpose: This study was aimed to identify pregnancy and childbirth experience of Vietnamese marriage migrant women who have pregnancy and childbirth experience during adaptation to Korea. Methods: A qualitative study was conducted, using focus group interview. Data were collected from October 2011 to March 2012 from 10 Vietnamese women of 2 focus groups who have experienced pregnancy or childbirth in Korea. Data were analyzed using content analysis in order to identify significant themes. Results: This study was analyzed into five major themes: 'difficulty of adaptation to other cultures', 'difficulty and joy of pregnancy', 'effort to live as a Korean', 'not-so-difficult childbirth', and 'unbearable postpartum conditions.' Conclusion: It is meaningful of this study to reveal this: for Vietnamese marriage migrant women, the support for adaptation to Korean culture and postpartum care is a priority rather than the necessity of development of the program about pregnancy and childbirth.

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실어증 선별검사 도구개발을 위한 예비연구 (A Preliminary Study for Development of the Aphasia Screening Test)

  • 김향희;이현정;김덕용;허지회;김용욱
    • 음성과학
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    • 제13권2호
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    • pp.7-18
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    • 2006
  • An aphasia screening test can serve a main purpose of differentiating aphasics from non-aphasic patients in a quick as well as efficient manner. As a preliminary study for developing a standardized aphasia screening test for Korean patients, we constructed an aphasia screening test constituting items from the Paradise' Korean version-the Western Aphasia Battery(P K-WAB). All test items were analyzed in order to extract items with optimal item discrimination and adequate item difficulty indices. From the results, we were able to select some items from each subtest with optimal results of discriminant function analysis for aphasic and normal control groups. It is expected, thus, that information on the item analysis could be utilized in developing a Korean aphasia screening test.

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