• 제목/요약/키워드: Variance Criterion

검색결과 199건 처리시간 0.042초

임펄스 및 가우시안 잡음영상에서 잡음제거에 관한 연구 (A Study on Denoising for Impulse and Gaussian Noise Images in Digital Images)

  • ;황용연;김남호
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2013년도 추계학술대회
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    • pp.779-781
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    • 2013
  • 다양한 멀티미디어 서비스에 대한 요구가 증가됨에 따라, 영상을 정보전달의 수단으로 사용하기 위한 기술들이 급격히 발전하고 있다. 영상에 첨가되는 여러 가지 잡음을 제거하기 위해, 평균 필터, 메디안 필터, 가중치 필터 방법 등이 제안되었으나 기존의 방법들은 잡음제거 및 에지 보존 성능이 미흡하다. 따라서 본 논문에서는 영상에 첨가되는 복합잡음을 효과적으로 제거하기 위해 먼저 잡음을 판단한 후, 변형된 메디안 필터와 적응 가중치 평균 필터를 이용하여 처리하는 알고리즘을 제안하였다. 그리고 시뮬레이션을 통해 기존의 방법들과 비교하였으며 판단의 기준으로 PSNR(peak signal to noise ratio)을 사용하였다.

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영아기질 측정도구(WBL)의 신뢰도 및 타당도 평가 (Confirmatory Analysis of Infant Temperament Inventory (WBL; What my baby is like))

  • 방경숙
    • 부모자녀건강학회지
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    • 제4권2호
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    • pp.32-42
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    • 2002
  • This study was conducted to test the reliability and validity of "What my baby is like(WBL)" that was developed by Pridham et al. for measuring infant temperament. 37 subjects were participated four times-1, 3, 6, and 12months, and 146 cases were analyzed. The construct validity for the scale was tested by factor analysis with four factor loading solution based on the previous study. One item was excluded because total-item correlation was too low, so that the number of total items were eighteen. The analysis yielded four well defined factors: amenability and persistence, activity, reactivity, and adaptability. These four factors explained 57.62% of the variance in the infant temperament. The criterion related Validity was confirmed by the relationship between the infant temperament and HOME, and between the infant temperament maternal confidence in childrearing. The reliability of the scale was determined with Cronbach's alpha coefficient and Guttman split-half coefficient. Cronbach's alpha was .86, for 18 items, and Guttman split-half cofficient was .81. In subscale analysis, Cronbach's alpha was .56~.84. In conclusion, WBL showed a high degree of validity and reliability, suitable in Korean infants for measuring temperament. In the further study, it would be necessary to refine the concept of temperament and to analyze the correlation between WBL and other temperament inventory.

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모성자존감 측정도구의 검증 (Confirmatory Analysis of Maternal Self-Report Inventory (Maternal Self-Esteem))

  • 한경자;방경숙
    • 부모자녀건강학회지
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    • 제2권
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    • pp.64-82
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    • 1999
  • This study was conducted to test the reliability and validity of Maternal Self-Report Inventory that was developed by Shea and Tronick for measuring maternal self-esteem. The subjects were 154 mothers. The construct validity for the scale was tested by factor analysis with five factor loading solution based on the previous study. One item was excluded because total-item correlation was too low, so that the number of total items were twenty-five, the analysis yielded five well defined factors: confidence on the maternal role, general ability of maternal role, caretaking ability, readiness on maternal role, and feeling on the pregnancy and deli very. These five factors explained 52.38% of the variance in the maternal self-esteem. Maternal self-esteem was not affected by maternal age, educational level, occupation, religion, delivery type, or parity. The reliability of the scale was determined with Cronbach's alpha coefficient and Guttman split-half coefficient. Cronbach's alpha was .82, for 26 items, and .83 if one item was deleted. Guttman split-half cofficient was .75. In subscale analysis, Cronbach's alpha was .63~.84. In conclusion. Maternal Self-Report Inventory showed a high degree of validity and reliability, suitable in Korean mothers for measuring maternal self-esteem. In the further study, it would be necessary to compare the maternal self-esteem between mothers with normal babies and premature babies, for confirming the criterion-related validity of the inventory.

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결합 다단계 일반화 선형모형을 이용한 다변량 경시적 자료 분석 (The Use of Joint Hierarchical Generalized Linear Models: Application to Multivariate Longitudinal Data)

  • 이동환;유재근
    • 응용통계연구
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    • 제28권2호
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    • pp.335-342
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    • 2015
  • 경시적 자료는 각 환자마다 시간에 따라 반복 측정되는 코호트 연구 등에서 많이 쓰인다. 본 연구는 반응변수 간 상관성을 고려할 수 있는 결합 다단계 일반화 선형모형을 이용하여, 다변량 경시적 자료 분석을 수행하였다. 한국 유전체 역학 연구에서 실시한 코호트 자료를 적합하고 결과를 해석한다. 조건부 아카이케 정보 기준을 이용하여 모형 선택을 하고, 변량효과들의 추정치들을 설명한다.

Appropriate identification of optimum number of hidden states for identification of extreme rainfall using Hidden Markov Model: Case study in Colombo, Sri Lanka

  • Chandrasekara, S.S.K.;Kwon, Hyun-Han
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2019년도 학술발표회
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    • pp.390-390
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    • 2019
  • Application of Hidden Markov Model (HMM) to the hydrological time series would be an innovative way to identify extreme rainfall events in a series. Even though the optimum number of hidden states can be identify based on maximizing the log-likelihood or minimizing Bayesian information criterion. However, occasionally value for the log-likelihood keep increasing with the state which gives false identification of the optimum hidden state. Therefore, this study attempts to identify optimum number of hidden states for Colombo station, Sri Lanka as fundamental approach to identify frequency and percentage of extreme rainfall events for the station. Colombo station consisted of daily rainfall values between 1961 and 2015. The representative station is located at the wet zone of Sri Lanka where the major rainfall season falls on May to September. Therefore, HMM was ran for the season of May to September between 1961 and 2015. Results showed more or less similar log-likelihood which could be identified as maximum for states between 4 to 7. Therefore, measure of central tendency (i.e. mean, median, mode, standard deviation, variance and auto-correlation) for observed and simulated daily rainfall series was carried to each state to identify optimum state which could give statistically compatible results. Further, the method was applied for the second major rainfall season (i.e. October to February) for the same station as a comparison.

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한국어판 아동학대 잠재성 도구의 신뢰도와 타당도 검증 (Reliability and Validity of Korean Version of the Child Abuse Potential Inventory)

  • 이소나;안혜영
    • Child Health Nursing Research
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    • 제25권2호
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    • pp.85-94
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    • 2019
  • Purpose: This study presents methodological research that aimed to verify the content validity, construct validity, reliability, and criterion-related validity of the Child Abuse Potential Inventory (CAPI), originally developed by Milner and then translated into Korean by Ahn. Methods: Data used in this study were collected from 209 mothers of infants, toddlers, and children of preschool age in D metropolitan city. The collected data were analyzed using SPSS version 24. Results: The Korean version of the Child Abuse Potential Inventory (K-CAPI) was developed by condensing 44 of the original 77 CAPI items. Four factors of K-CAPI were extracted using principal component analysis. These 4 factors-distress; problems with child, self, family, and others; unhappiness; rigidity-accounted for 54.01% of variance. The Cronbach's ${\alpha}$ was .96, the Guttman split-half coefficient was .88, and test-retest reliability was r=.86 (p<.001). Conclusion: The results of this study established the reliability and validity of the K-CAPI and found it to be an appropriate tool to evaluate mothers' potential to abuse their children.

한국 노인의 외로움 측정도구 개발 (Development of the Korean Geriatric Loneliness Scale (KGLS))

  • 이시은
    • 대한간호학회지
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    • 제49권5호
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    • pp.643-654
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    • 2019
  • Purpose: The purpose of this study was to develop and psychometrically test the Korean Geriatric Loneliness Scale (KGLS). Methods: The initial items were based on in-depth interviews with 10 older adults. Psychometric testing was then conducted with 322 community-dwelling older adults aged 65 or older. Content, construct, and criterion-related validity, classification in cutoff point, internal consistency reliability, and test-retest reliability were used for the analysis. Results: Exploratory factor analysis showed three factors, including 15 items explaining 91.6% of the total variance. The three distinct factors were loneliness associated with family relationships (34.3%), social loneliness (32.4%), and a lack of belonging (24.9%). As a result of confirmatory factor analysis, 14 items in the three-factor structure were validated. Receiver operating characteristic analysis demonstrated that the KGLS' cutoff point of 32 was associated with a sensitivity of 71.0%, specificity of 80.2%, and area under the curve of .83. Reliability, as verified by the test-retest intraclass correlation coefficient, was .89, and Cronbach's ${\alpha}$ was .90. Conclusion: As its validity and reliability have been verified through various methods, the KGLS can contribute to assessing loneliness in South Korean older adults.

간호대학생의 한국어판 윤리적 민감성 측정도구 타당도와 신뢰도 (Validity and Reliability of the Korean Version of the Ethical Sensitivity Questionnaire for Nursing Students)

  • 민혜영;김윤정;이정민
    • 지역사회간호학회지
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    • 제31권4호
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    • pp.503-513
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    • 2020
  • Purpose: The purpose of this study was to evaluate the validity and reliability of the Korean version of the Ethical Sensitivity Questionnaire for Nursing Students (KESQ-NS). Methods: The participants were 138 nursing students who have experience in clinical practice. The Korean version of ESQ-NS (KESQ-NS) was examined using content validity, construct validity, criterion-related validity, and testing of internal consistency reliability. Data were collected from November to December of 2019 through an online-survey. Results: The KESQ-NS that was composed of 13 items was divided into three dimensions: Critical understanding of the patient, patient holistic care, patient privacy, and confidentiality. The instrument explained 67.9% of the total variance for ethical sensitivity. Cronbach's α was .88. Conclusion: The KESQ-NS showed good validity and reliability. This instrument can be used to evaluate ethical sensitivity in nursing students in Korea.

간호사를 위한 말기 환자 존엄간호 측정도구 개발 (Development and Validation of a Dignity in Care Scale of Terminally Ill Patients for Nurses)

  • 안윤실;오복자
    • 대한간호학회지
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    • 제53권3호
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    • pp.340-358
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    • 2023
  • Purpose: This study aimed to develop an instrument to showcase Dignity in Care of Terminally Ill Patients for Nurses and to examine its validity and reliability. Methods: A total of 58 preliminary items on dignity in care of terminally ill patients for nurses were selected using content validity analysis and expert opinions on 97 candidate items derived through a literature review and qualitative focus group interviews. Questionnaires were administered to 502 nurses caring for terminally ill cancer patients at hospice and palliative care institutions. The data were analyzed using item analysis, exploratory and confirmatory factor analysis, convergent and discriminant validity, and Pearson correlation for criterion validity, reliability was tested using Cronbach's alpha. Results: The final instrument consisted of 25 items, with four factors identified through confirmatory factor analysis. Four factors-ethical values and moral attitudes, interaction-based communication, maintaining comfort, professional insight and competence-accounted for 61.8% of the total variance. Cronbach's α for total items was .96, and test-retest reliability of intraclass correlation coefficient was .90. Conclusion: Since its validity and reliability have been verified through various methods, the Dignity in Care Scale of Terminally Ill Patients for Nurses can be used for develop nursing interventions and improve dignity in care of terminally ill patients.

평균-VaR 기준과 최적 포트폴리오 선택 (The Mean-VaR Framework and the Optimal Portfolio Choice)

  • 구본일;엄영호;추연욱
    • 재무관리연구
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    • 제26권1호
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    • pp.165-188
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    • 2009
  • 본 연구는 개별 자산의 수익률 분포에 대한 가정 없이 평균-VaR 기준에서의 프론티어 포트폴리오를 구하고, 수익률 분포의 고차 적률에 대한 투자자의 선호가 반영된 최적 포트폴리오를 선택하는 방법을 제시하였다. 프론티어 포트폴리오를 구하기 위해 수익률 분포에 대한 가정이 필요하지 않은 그리드와 랭크 방법을 제시하였고 최적 포트폴리오를 선택하기 위해 수익률 분포의 4차 적률까지 고려된 효용함수를 사용하였다. 제시한 방법론을 실제 자료에 적용해 보기위해 모건 스탠리에서 제공하는 선진국 지수, 개발도상국 지수, KOSPI 지수의 주별 수익률 자료를 사용하였다. 평균-VaR 기준과 평균-분산 기준에서의 프론티어 포트폴리오를 구하고 각 기준에서의 최적 포트폴리오를 선택해 서로 비교하였다. 표준편차의 차이뿐만 아니라 효용함수의 수준과 주별 기대수익률로 표현되는 확실성 등가의 차이를 살펴봄으로써 두 기준 간의 경제적 의미 차이에 대해서도 살펴보았다. 또한 부트스트래핑을 이용한 역사적 시뮬레이션의 방법을 사용해 두 기준 간 발생한 차이가 통계적으로 유의한 지를 본 연구에서 적용한 자료에서는 평균-VaR 기준의 투자자가 평균-분산 기준의 투자자에 비해 더 큰 표준편차를 지닌 최적 포트폴리오를 선택하고 위험 회피도가 큰 투자자일수록 평균-VaR 기준에서의 효용이 크고 확실성 등가도 더 크게 나타나는 경향이 나타났다. 그러나 두 기준 간 발생한 차이가 통계적으로 유의하지 않게 나타나 표준편차의 차이와 경제적인 의미 차이가 크지 않다는 사실을 확인하였다.

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