• 제목/요약/키워드: Standard normal Distribution

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대전지역 중학생의 혈압 분포와 비만지수 및 일부 환경인자와의 관계 (Blood Pressure Distribution of Adolescents in Taejon City and its Relationship with Obese Index and Several Environmental Factors)

  • 이정원;나효숙
    • 대한지역사회영양학회지
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    • 제1권2호
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    • pp.178-188
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    • 1996
  • Blood pressure distribution of adolescents and its several related factors including obesity were investigated through blood pressure measuring by automated oscillometric method, anthropometry, and questionnaire. Subjects were 480 female and 480 male middle school students living in Taejon. Mean values of systolic(SBP)/diastolic(DNP) blood pressure of male and female students were 118.4$\pm$11.0/69.5$\pm$9.6 mmHg and 116.9$\pm$10.4/69.5$\pm$8.6 mmHg, respectively. Their blood pressures, particularly SBP, increased with age and showed higher value in the males than in the females. All frequency distributions of SBP and DBP, by sex and age, showed normal curves and their 50th, 90th, and 95th percentiles were presented. As obese index increased, both SBP and DBP were elevated and the prevalence of hypertension which was classified by Task Force Report(1987) increased, particularly in male students. Body weight and BMI were positively correlated with both SBP and DBP, and hight was also positively correlated with SBP or DBP. Our data inicated that blood pressure and hypertension prevalence of adolescents tended to increase and various internal and external environmental factors affected them. It was emphasized that blood pressure measurement should be done in every medical examination of adolescents and the nationwide Korean standard of blood pressure for adolescents have to be prepared. (Korean J Community Nutrition 1(2) : 178-188, 1996)

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공공사업으로 인한 어업피해 범위와 피해정도 추정의 새로운 통계학적 접근 (A New Statistical Approach for the Estimation of Range and Degree of Fisheries Damages Caused by Public Undertaking)

  • 강용주;김기수;장창익;박청길;이종섭
    • 수산경영론집
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    • 제35권1호
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    • pp.117-132
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    • 2004
  • This study attempts to suggest a new approach of the estimation of range and degree of fisheries damages caused by a large scale of reclamation undertaken in coastal area using the central limit theorem(CLT) in statistics. The key result of the study is the introduction of the new concept of critical variation of environmental factor($d_{c}$). The study defines $d_{c}$ as a standard deviation of the sample mean($\bar{X}$) of environmental factor(X), in other words, $\frac{\sigma}{ \sqrt{n}}$. The inner bound of $d_{c}$ could be the area of fisheries damages caused by public coastal undertaking. The study also defines the decreasing rate of fisheries production$\delta_{\varepsilon}$, in other words, degree of fisheries damages, as the rate of change in the distribution of sample mean(($\bar{X}$), caused by the continuous and constant variation of environmental factor. Therefore $\delta_{\varepsilon}$ can be easily calculated by the use of table of the standardized normal distribution.

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장기간 상시계측을 통한 감쇠율 평가 (Damping Ratio Evaluation Using Long-Term Ambient Vibration)

  • 김용철;윤성원
    • 한국공간구조학회논문집
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    • 제18권1호
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    • pp.77-84
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    • 2018
  • The identification of damping ratios in buildings is a well-known problem and appears to be of important and crucial interest in the safety and serviceability design. When compared to an estimation of the stiffness, i.e. natural frequency, and mass, the damping ratio is the most difficult quantity to determine. Many previous studies have examined the characteristics of damping ratios from ambient vibration, but the measurement time is roughly within 2 hours. In this paper, characteristics of damping ratios and natural frequencies of 4 story RC building were investigated using long-term ambient vibration. Free vibrations were obtained using random decrement technique, and damping ratios were evaluated by the envelop function, continuous wavelet transform, and logarithmic decrement. It was found that although the natural frequencies show little variations with time, the damping ratios show some variations with time and the largest variations found in the damping ratios obtained from the continuous wavelet transform. The damping ratios from the envelop function showed the smallest mean and standard deviation. And the probability distribution of damping ratios seems to follow the logarithmic normal distribution.

비만한 성인남성의 음주 및 식이습관의 특성연구 (The Case Study of Alcohol & Food Habits in Obese Adult Men)

  • 이명종;이영준
    • 한방비만학회지
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    • 제2권1호
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    • pp.53-61
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    • 2002
  • Objective: Obesity is closely related to several factors such as genetic factors, energy intake and energy expenditure. It was said that alcohol & food habits were important to formation of obesity. The purpose of this study are to find out the alcohol & food habitual characteristic of obese adult men and to promote the health of these men. Method: From May, 2000 to November, 2001, We collected 75 eases obese patients, who visited to the Health Examination Center Dept. of Kangnam oriental medicine hospital, Dongguk University who took the health examination, and control group who were matched by age and sex. We investigated the alcohol & food habits by questionnaire. Results and Conclusions: 1. The patients over BMI 25 were in excess of the standard of obesity such as Modified Broca $^{\circ}{{\O}}s$ Index. Percent Body Fat, Abdominal Fat Distribution. But, the patients below BMI 20 were normal range of obesity degree. 2. Abdominal Fat Distribution was increased according to age and physical activity was decreased in obese group. 3. The mean of total calory by alcohol in a month was 4324.6kcal in obese group while control group was 2206.8kcal. 4. In the comparison of food habit, obese group is higher than control group in 7 articles of the 13 articles which influenced obesity.

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Analysis of the influence of panel characteristics on odor measurement based on the air dilution olfactory method in Korea

  • Kim, Sun-Tae;Lee, Seokjun;Yim, Bongbeen
    • Environmental Engineering Research
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    • 제24권1호
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    • pp.91-98
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    • 2019
  • This study was to objectify differences in the results of odor testing according to the characteristics of panel members that participate in air dilution olfactory method (ADOM) testing. When differences in the results of olfactory testing were reviewed in relation to characteristics of the panelists, the result of entire panels for the site boundary Proficiency Testing Materials (PTMs) showed no difference according to panelist sex, age, smoking status, and past participation in ADOM tests. As for the outlet PTMs, distinct differences appeared in relation to the smoking status and age of panelists. The frequency distribution for all the panelists (Dev($D/T_{total}$)) showed a form similar to a normal distribution, so it is thought to be more appropriate for the review of effect of panelist characteristics on the result of air dilution olfactory tests. In addition, the ADOM testing method implemented as the standard method for odor compounds in Korea (Dev($D/T_3$)) will have to be implemented along with a concurrent assessment, for the purpose of identifying the effect of panelist characteristics on administrative dispositions against malodors.

Mw 5.5~6.5 지진동의 위상특성과 계속시간 및 PGA와의 관계 (Relationship between Phase Properties, Significant Duration and PGA from the Earthquake Records of Mw 5.5~6.5)

  • 최항;윤병익
    • 한국지진공학회논문집
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    • 제23권1호
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    • pp.55-70
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    • 2019
  • The phase properties of ground acceleration records from Mw 5.5~6.5 earthquakes are analyzed. The interrelationships between phase properties and significant durations, as well as PGA, are clarified through both of theoretical and empirical approaches. The probabilistic characteristics of phase information is also discussed based on previous studies and it is shown that circular normal distribution is the most appropriate probability distribution for the phase angle and phase difference. Whereas those variates can be modeled by Gaussian random variables. From the survey results on the frequency dependency of the phase statistics, a simple model is introduced, which is possible to express the frequency dependency of phase information. It is also shown that the significant duration can be controlled by appropriately chosen standard deviation of phase difference for 4~8Hz frequency band and additional consideration of phase scattering in higher frequency band through a series of Monte Carlo simulations. The source of phase scattering effect is also pointed out and discussed.

적혈구(赤血球) Protoporphyrin과 철분대사(鐵分代謝)에 관(關)한 연구(硏究) (A Study on Red Cell Protoporphyrin Concentration and Iron Metabolism)

  • 조경환;채범석
    • Journal of Nutrition and Health
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    • 제7권3호
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    • pp.1-13
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    • 1974
  • The relative state of human iron storage may be ascertained more reliably through determination of the serum iron, iron binding capacity, transferrin saturation and absorption of radioactive iron in conjunction with studies of red cell morphology than from the study of red cell morphology alone. Recent investigations have shown that there is an increase in red cell protoporphyrin concentration in iron deficiency anemia. The significance of the red cell protoporphyrin has been discussed greatly during the years since its discovery. Two of the main factors which appear to influence the amaunt of protoporphyrin are increased erythropoiesis and factors interfering with the utilization of iron in the synthesis of hemoglobin, and iron deficiency. Recently Heller et al. have described a simplified method for blood protoporphyrin assay and this technique could be used assess nutritional iron status, wherein even minor insufficiencies are detectable as increased protoporphyrin concentrations. Based on the evaluation of the relationship between nutritional iron status and red cell protoporphyrin as an index suitable for the detection of the iron deficiency is described in this paper. RESULTS 1. Hemoglobin Concentrations and Anthropometric Measurements. The mean and standard deviations of the various anthropometric measurements of different age and sex groups are shown in table 1. There measurements have been compared with the Korean Standard. In the absence of local standards for arm circumference and skin-fold thickness over triceps, they have been compared with the standard from Jelliffe. Table 2,3, and 4 give anthropometric measurements and frequency (%) of anemia in children surveyed. The mean height of the children studid was 10 to 20 percent; below the Korean Standard. The distribution of height below 80 percent of the Standard was 21.2 percent, however, among anemic group this percentage was 27.7 percent. In general, the mean weight of the children was 10 to 15 percent below the Korean Standard. The percentage of children with weight less than 80 percent of the Standard was about 35 percent. But in the anemic group of the children, this percentage was 44 percent. The mean arm circumference was about 15 percent lower than the Jelliffe's standard. 61.2 percent of the children had values of arm circumference below 80 percent of the standard. Children with low hemoglobin levels, this percentage was 80 percent. The mean skinfold thickness over the triceps of the children studied was about 25 Percent lower than the Jelliffe's standard and 61.2 percent of the children had the value less than 80 percent of the standard. Among anemic children, this percentage was 70.8%. As may be seen from table 5, the mean hemoglobin concentration of the total group was 11.3g/100ml. Hemoglobin concentration was less than 11.0g/100ml. in 65(36.5%) of the 178 children. The degree of anemia in most of these children was mild with a hemoglobin level of less than 8.0g/100ml. found in only one child. In general, the prevalence of anemia was high in female children than male and decreased its frequency with increasing age. Relatively close relationship was observed between hemoglobin level and anthrophometric measurements especially high between arm circumference and skinfold thickness and hemoglobin but very low in height and low in weight and hemoglobin level, estimated by chi-square value. II. Serum iron, Transferrin saturation (1) Serum iron, and transferrin saturation Serum iron, transferrin saturation and red cell protoporphyrin concentrations were estimated in sub-sample of 84 children from 1 to 6 years and 24 older children between 7 and 13 years of age. The findings are presented in table 6. The mean serum iron concentration of the total group was 59ug/100ml. However, the level incrased with age from 36.6ug/100ml. (1-3years) to 80.8ug/100ml. (7-13 years). 60 percent of these children had a serum iron level less than 50ug/10ml. in the 1-3 years age group and 31.4 percent for 4-6 years group. These contrast with the finding of 12.5 percent anemic children in the 7-13 years age group. The mean transferrin saturation for the total group was 18.1 percent and frequency of anemia by transferrin saturation was observed same pattern as serum iron concentration. (2) Red cell protoporphyrin concentrations. (a) Red cell protoporphrin levels of children: Red cell protoporphyrin and other biochemical data are shown in table 4. The mean concentration in red cell of all children was fround 46.3ug/100ml. RBC. and differences with age groups were observed; in the age group 1-3 years, the mean concentration was $59.5{\pm}32.14$ ug/100ml. RBC; 4-6 years $44.1{\pm}22.57$ ug/100ml. RBC. and 7-13 years, $39.0{\pm}13.56$ ug/100ml. RBC. (b) Normal protoporphyrin values in adults: It was observed that in 10 normal adult males studied here the level of protoporphyrin in red cell ranged from 18 to 54 ug/100ml. RBC. and the mean concentration was $47.5{\sim}14.47$ ug/100ml. RBC. Other biochemical determination made on the same subjects are presented in table 8. (c) Red tell protoporphyrin concentration of occupational blood donors: The results of analyses for red cell protoporphyrin as well as serum iron, transferrin saturation and hemoglobin in the 76 blood donors are presented in table 7 and 8. In this experiment, donors were selected at random, however, most of them bled repeatedly because of poor economic situation, I doubt. Table 9 shows the distribution of red cell protoporphyrin concentration and hemoglobin concentration of occupational donors. The mean hemoglobin value for the total was 11.9 g/100 ml. When iron deficiency anemia is defined as a transferrin saturation below 15%, prevalence of anemia was 47.4 percent and the mean serum iron was 27.1ug/100ml. and red cell protoporphyrin, 168.3ug/100ml. RBC. However, mean serum iron and protoporphyrin concentration of above 15% transferrin saturation were 11.6 ug/100 ml. and 58.8 ug/100 ml. RBC. respectively. The mean Protoporphyrin concentration of non-anemic (above 15% transferrin saturation) donors was slightly higher than the results of normal adult males.

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측정결과의 불확도산정을 위한 모델링과 불확도 전파에 관한 연구 (A Study on the Modeling and Propagation to Evaluate Uncertainties in Measurement Results)

  • 김종상;조남호
    • 한국컴퓨터정보학회논문지
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    • 제8권4호
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    • pp.165-175
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    • 2003
  • 국제적으로 측정결과의 신뢰성을 판단할 수 있는 척도로서 불확도(Uncertainty)개념이 도입되고 국제 표준화기구(ISO)가 여러 국제기구와 합동으로 "측정불확도표현지침(GUM)"을 1993년에 발간하게 되었다. 본 논문에서는 시료의 산포가 존재하는 경우 시료산포를 불확도 인자로 적용하여 측정결과에 대한 불확도를 평가할 수 있는 측정모델을 구축하여 제시하고, GUM에서 제시한 불확도 전파법칙의 문제점을 분석하여 이를 보완할 수 있는 새로운 불확도의 평가방법으로 몬테칼로 시뮬레이션을 이용한 컴퓨터프로그램 활용의 필요성을 논하고자 한다. 또한 이러한 이론적 근거를 바탕으로 하여 불확도를 평가할 수 있는 컴퓨터 프로그램 개발사례를 제시하고자 한다. 제시하고자 한다.

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식스시그마의 1.5σ 이동에 대한 소고 (A Note for 1.5σ Shift of Six Sigma)

  • 박종훈
    • 산업경영시스템학회지
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    • 제45권1호
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    • pp.31-40
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    • 2022
  • Six Sigma is a philosophy and systematic methodology for quality improvement. It encourages continuous quality improvement efforts to achieve the ideal goal of 6σ. Sigma(σ) is a statistic representing the standard deviation of the normal distribution, and 6σ level means a level where the tolerance of the specification is six times the standard deviation of the process distribution. In terms of the defective rate, the 6σ level achieves the 0.002 defectives per one million units. However, in the field, the 6σ level is used in the sense of achieving 3.4 defects per one million opportunities, which shows a large gap from the 6σ level in the statistical viewpoint. This is because field practitioners accept a 1.5σ shift of the mean of process when calculating the defective rate under sigma level. It said that the acceptance of 1.5σ shift of the mean is from experience, but there is no research or theoretical explanation to support it logically. Although it is a non-scientific explanation based on experience, considering that there has been no objection to the 1.5σ shift for a long time and it is rather accepted, it is judged that there is a reasonable basis for the 1.5σ shift. Therefore, this study tries to find a reasonable explanation through detective power of control chart via the run-rules to the 1.5σ shift empirically recognized by practitioners.

A Heuristic Methodology for Fault Diagnosis using Statistical Patterns

  • Kwon, Young-il;Song, Suh-ill
    • 품질경영학회지
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    • 제21권2호
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    • pp.17-26
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    • 1993
  • Process fault diagnosis is a complicated matter because quality control problems can result from a variety of causes. These causes include problems with electrical components, mechanical components, human errors, job justification errors, and air conditioning influences. In order to make the system run smoothly with minimum delay, it is necessary to suggest heuristic remedies for the detected faults. Hence, this paper describes a heuristic methodology of fault diagnosis that is performed using statistical patterns generated by quality characteristics The proposed methodology is described briefly as follows: If a sample pattern generated by random variables is similar to the number of prototype patterns, the sample pattern may be matched by any prototype pattern among them to be resembled. This concept is based on the similarity between a sample pattern and the matched prototype pattern. The similarity is calculated as the weighted average of squared deviation, which is expressed as the difference between the relative values of standard normal distribution to be transformed by the observed values of quality characteristics in a sample pattern and the critical values of the corresponding ones in a matched prototype pattern.

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