• Title/Summary/Keyword: Uncertainty

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Calculation of Vertical Wind Profile Exponents and Its Uncertainty Evaluation - Jeju Island Cases (풍속고도분포지수 산정 및 불확도 평가 - 제주도 사례)

  • Kim, You-Mi;Kim, Hyun-Goo;Kang, Yong-Heack;Yun, Chang-yeol;Kim, Jin-Young;Kim, Chang Ki;Kim, Shin-Young
    • Journal of the Korean Solar Energy Society
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    • v.36 no.4
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    • pp.11-20
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    • 2016
  • For accurate wind resource assessment and wind turbine performance test, it is essential to secure wind data covering a rotor plane of wind turbine including a hub height. In general, we can depict wind speed profile by extrapolating or interpolating the wind speed data measured from a meteorological tower where multiple anemometers are mounted at different heights using a power-law of wind speed profile. The most important parameter of a power-law equation is a vertical wind profile exponent which represents local characteristics of terrain and land cover. In this study, we calculated diurnal vertical wind profile exponents of 8 locations in Jeju Island who possesses excellent wind resource according to the GUM (Guide to the Expression of Uncertainty in Measurement) to evaluate its uncertainty. Expanded uncertainty is calculated by combined standard uncertainty, which is the result of composing type A standard uncertainty with type B standard uncertainty. Although pooled standard deviation should be considered to derive type A uncertainty, we used the standard deviation of vertical wind profile exponent of each day avoiding the difficult of uncertainty evaluation of diurnal wind profile variation. It is anticipated that the evaluated uncertainties of diurnal vertical wind profile exponents at 8 locations in Jeju Island are to be registered as a national standard reference data and widely used in the relevant areas.

A Correlational Study on Uncertainty and Coping in Families of children with Cancer (암 환아 가족의 질병에 대한 불확실성과 대처양상에 관한 연구)

  • 민영숙
    • Journal of Korean Academy of Nursing
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    • v.24 no.4
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    • pp.529-544
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    • 1994
  • For most parents their child's illness and hospitalization is strssful. Internal stress and over anxiousness leads to uncertainty. Parents have a variety of ways of coping when faced with such stress factors, especialy when the child has cancer. The purpose of this study was to examine the relationship between uncertainty in illness and mastery and coping styles in parents of pediatric cancer patients, and further to identify differences between three groups of subjects. A cross-sectional descriptive correlational design was used in this study to investigate the relationship among the three groups. The sample was composed of 59 parents of children with cancer in pediatric wards in three hospitals in Seoul : 21 in Group 4 with a child newly diagnosed with cancer : 25 in Group B, with a child under treatment and rehospitalized with a relapse : and 13 in Group C, with a child with a terminal cancer, A formalized questionnaire which included demegrapic information and consisted of 75 items was used in this study ; The Parent Perception of Uncertainty Scale(PPUS) adapted form Mishel’s Uncertainty in Illness Scale, Pearlin & Schooler's Mastery Scale(MS) and Folkman & Lazarus’s Ways of Coping Checklist(WCC) were used to measure the variables : uncertainty in illness, mastery, and coping styles. A pretest was conducted on the questionnaire items for reliability. The results gathered were analyzed using SPSS /PC/sup +/. Data analysis included descriptive correltional statistics such as ANOVA, Pearson Correlation Coefficient, amd chi square test. The conclusions of this analysis are summarized as follows : 1. A higher level of uncertainty was seen among parents of children with terminal cancer. 2. The first hypothesis that uncertainty in illness would differ among the three groups was supported(F=4.182, P=.020). The second and third hypotheses that mastery and coping styles would differ among the three groups were not supported. There was a correlation between uncertainty, mastery, and coping styles which was positive, also there was a positive correlation between mastery and coping style(r=.3744, P<.001) but a negative correlation between uncertainty md mastery(r=-.4749, P<.01). From the above results, it can be concluded that prediciting and controlling uncertainty in illness by considering coping styles and mastery are necessary for improved, efficient nursing interventions.

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A Correlational Study on Uncertainty, Coping and Depression of Cancer Patients (일개지역 암환자의 불확실성과 대처 및 우울에 관한 연구)

  • 이윤정;함은미;김금순
    • Journal of Korean Academy of Nursing
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    • v.31 no.2
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    • pp.244-256
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    • 2001
  • The purpose of this study was to investigate the effects of coping mechanisms on uncertainty and depression. The subjects were 71 cancer patients selected from Junbook National University Hospital, and the data collection period was from June 21 to October 19 of 2000. Uncertainty was measured by using Mishel's Uncertainty Scale, problem- focused coping, and emotional-focused coping. The data was collected by a questionnaire developed by Lee (1984), and then depression measured by using Beck's depression scale. program by Pearson Correlation Coefficients, and Path analysis. The results were as follows : 1. The mean uncertainty score was 59.17, the mean problem-focused coping score was 48.78, the mean emotional-focused coping score was 42.52. 2. The mean depression score was 15.77. 3. Uncertainty in illness was significantly related to depression (p=0.003) and emotional-focused coping (p=0.028), but uncertainty was not associated with coping mechanisms. 4. When analyzed multiple regression between uncertainty, problem-focused coping, emotional- focused coping, and depression, more specifically emotional-focused coping showed a stronger association with depression than problem-focused coping. 5. Depression was highly correlated with economic status (p=0.015), educational background (p=0.005), duration of disease (p=0.045). 6. Problem-focused coping and emotional-focused coping appeared to function as moderators instead mediators on the relation between uncertainty and depression. In addition, as a whole, uncertainty showed a significant moderating effect on depression, while problem-focused coping did on depression. Finally, limitation of present findings were discussed and implications for future studies are suggested.

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The Relationship between Spiritual Health and Uncertainty in Cancer Patients Having Chemotherapy (항암화학요법을 받는 암환자의 영적건강과 불확실성의 관계)

  • Ahn, Hwa-Jeen;Tae, Young-Sook;Han, Young-In
    • Asian Oncology Nursing
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    • v.7 no.2
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    • pp.107-118
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    • 2007
  • Purpose: The purpose of this study was to provide the basic data for development of nursing intervention to decrease the uncertainty in cancer patients having chemotherapy through promoting their spiritual health and identifying the relationship between spiritual health and uncertainty. Method: 174 cancer patients who were admitted for chemotherapy at hospital were recruited from the 7th March to the 10th April, 2006. Two instruments have been used for this study. One was Highfield's Spiritual Health Inventory and the other was Mishel's MUIS(Mishel Uncertainty in Illness Scale). The collected data was analyzed by frequency, percentage, mean value, average mean, standard deviation, t-test, Scheffe's test, ANOVA and Pearson Correlation Coefficients with the SPSS PC 12.0 program. Results: The average mean value of the spiritual health $3.50{\pm}\;.48$ and the uncertainty was $1.91{\pm}\;.46$. It meant that the relationships between spiritual health and uncertainty were shown to have a moderately negative correlation(r=-.489, p= .000). This means that the greater is the spiritual health, the less is the patient's uncertainty. Conclusions: It was identified that cancer patients having chemotherapy had moderate spiritual health and uncertainty, and negative correlation between spiritual health and uncertainty. Therefore, it will be necessary for the development of spiritual nursing intervention strategies to relieve the uncertainty among cancer patients having chemotherapy.

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Uncertainty Assessment Using Monte Carlo Simulation in Gas Flow Measurement (기체 유량 측정에서 몬테 카를로 모사를 이용한 측정불확도 평가)

  • Lee, Dae-Sung;Yang, In-Young;Kim, Chun-Taek;Yang, Soo-Seok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.12
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    • pp.1758-1765
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    • 2003
  • Monte Carlo simulation(MC) method was used as an uncertainty assessment tool for gas flow measurement in this paper. Uncertainty sources for gas flow measurement were analyzed, and probability distribution characteristics of each source were discussed. Detailed MC methodology was described including the effect of the number of simulation. The uncertainty result was compared with that of the conventional sensitivity coefficient method, and it was revealed that the results were different from each other for this particular gas flow measurement case of which the modelling equation was nonlinear. The MC was comparatively simple, convenient and accurate as an uncertainty assessment method, especially in cases of complex, nonlinear measurement modelling equations. It was noted that the uncertainty assessment method should be selected carefully according to the mathematical characteristics of the measurement.

Uncertainty Analysis for the Multi-path Ultrasonic Flowmeter UR- 1000 with Dry Calibration (간접 교정에 의한 다회선 초음파유량계 UR-1000 불확도 분석)

  • Hwang, Shang-Yoon;Park, Sung-Ha;Park, Kyung-Am
    • 유체기계공업학회:학술대회논문집
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    • 2002.12a
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    • pp.378-386
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    • 2002
  • Multi-path ultrasonic Sow measurement system uncertainty is determined by assigning an expected error of each component of flow measurement and then defining the total flow measurement uncertainty as square root of the sum of squared values of the individual error. Sources of uncertainty for flow measurement are geometry, transit time and velocity profile integration uncertainty. A theoretical uncertainty model for multi-path ultrasonic transit time flowmeter configured with parallel 5 chords, is derived from and calculated by dry calibration method.

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Long Term Stability of Uncertainty Analysis of Light Oil Elow Standard System (장기 안정성을 고려한 경질유 유량표준장치 불확도 평가)

  • Lim, Ki-Won;Choi, Jong-Oh
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.10 s.241
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    • pp.1130-1138
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    • 2005
  • A national standard system for the petroleum field has been developed to calibrate and test the oil flow meters in Korea. The operating system and the uncertainty of the system were evaluated by the peer reviewers of foreign national metrology institutes in 2002. Since the characteristics of the system might be changed by time, the uncertainty of the system is reevaluated with the consideration of the long term stability of the system. It is found that the system has a relative expanded uncertainty of 0.048 $\%$ in the range of $15\~120\;m^3/h$. According to the uncertainty budget, the uncertainties of the fluid density and the final mass measurement, which are temperature dependent, contribute about $94\%$ of the total uncertainty in the oil flow standard system

Verification on the Measurement Uncertainty for Surface Roughness (표면거칠기측정에 대한 측정불확도 추정방법)

  • Kim, Chang-Soon;Park, Min-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.4
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    • pp.40-45
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    • 2010
  • Evaluation of uncertainty is an ongoing process that can consume time and resources. It can also require the service of someone who is familiar with data analysis techniques. Therefore, it is important for laboratory personnel who are approaching uncertainty analysis for the first time to be aware of the resources required. International inclination of measurement filed to guarantee the traceability and confidence of measurement results discards the error concept and instead analyzes the measurement uncertainty. In this paper, we analyzed the elements of measurement uncertainty on surface roughness test which are the important things in mechanical parts test. Repeat the test by 3 men, the measurement uncertainty could be calculated.

과업의 불확실성이 최종사용자컴퓨팅 특성과 최종사용자의 만족도에 미치는 영향

  • 김창기;이진주
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1993.04a
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    • pp.329-338
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    • 1993
  • The main objective of this paper is analyzing the effects of task uncertainty on EUC characteristics and end user satisfaction. Task uncertainty were identified as an important determinant of EUC characteristics. And the moderating effect of task uncertainty on the relationship between EUC characteristics and end user satisfaction was suggested. A field study was undertaken to test the hypothesized relationships among task uncertainty, EUC characteristics, and end user satisfaction Data were collected from 138 end-user of 19 Korean business organizations. The empirical results indicated that task uncertainty was significantly related to EUC characteristics and that task uncertainty had significant effect on the relationship between EUC characteristics and end user satisfaction. Implications and future research directions are drawn for the management of EUC and for further research on EUC.

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Procedure for Uncertainty Evaluation of a Precision Electric Force Measuring Device and Its Application (고정밀 전기식 힘측정기의 불확도평가 절차 및 응용)

  • Kim, Gab-Soon;Kang, Dae-Im
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.12
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    • pp.161-167
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    • 1999
  • This paper describes the calibration method and the calculation equations of expanded uncertainty for a precision electric force measuring device. The calibration of the electric force measuring device is performed three times (0 ${\circ}$(first time), $120{\circ}$(second time), $240{\circ}$(third time)) at each calibration point. It is usually selected ten points from zero load to rated load of the electric force measuring device. The expanded uncertainty is calculated by combining A type standard uncertainty and B type standard uncertainty. The calibration method and the calculation equations of expanded uncertainty can be widely used in the calibration of the precision electric force measuring device.

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