• 제목/요약/키워드: Standard normal Distribution

검색결과 322건 처리시간 0.029초

2001년도 국민건강영양조사 자료를 이용한 고혈압 유무에 따른 식생활 비교 및 평가 (Comparative Analysis and Evaluation of Dietary Intake between with and without Hypertension Using 2001 Korea National Health and Nutrition Examination Survey (KNHANES))

  • 박정현;문현경
    • Journal of Nutrition and Health
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    • 제40권4호
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    • pp.347-361
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    • 2007
  • The purpose of this study was to analyze and evaluate dietary intake between with and without hypertension. Study subjects were more than 30 years old adults (n = 3,806) who participated in the 2001 Korea National Health and Nutrition Examination Survey. People who have 'self-recognition about hypertension' and 'having diet for hypertension' were excluded. Using the WHO standard, subjects were divided into the hypertensive group (SBP> 140, DBP> 90) and the normal group (SBP< 140, DBP< 90). The Body Mass Index (BMI) and the Waist-Hip Ratio (WHR) of a hypertensive group were higher than those of a normal group (p < 0.01). The distribution of the subjects for smoking, alcohol consumption, exercise, stress, preference of salty food were not significantly different between a normal group and a hypertensive group (p>0.05). Dietary intakes were investigated by the 24-hour recall method. When food and dish intakes analyzed by sociodemographic factors, normal group consumed more fruits than those of a hypertensive group. Statistical significant were shown at female group, residences in metropolitan area and having elementary school education (p<0.05). Hypertensive group consumed more alcoholic beverages than those of a normal group at 'age 39-39', 'aged 50-64', 'high economic status', 'low economic status' and 'residences in metropolitan' (p<0.05) The amount of intakes for fat, potassium, thiamin, vitamin C and alcohol were significantly different between the normal group and the hypertensive group (p<0.05). The highest score of the Dietary diversity score (DDS) was 4 in both normal group and hypertensive group. Normal group showed high Nutrition Density (ND) of vitamin C and hypertensive group showed high ND of sodium. In summary, these results showed that significant difference for people with hypertension were intakes of fruits, alcohol, thiamin, vitamin C. And these results differed by sociodemographic groups. Therefore, the differential approach in each group is demanded for prevention and control of the hypertension.

mini-Wright Peak Flow Meter에 의한 PEFR 측정의 정확도 (An Evaluation of the Accuracy of Mini-Wright Peak Flow Meter)

  • 고영일;최인선;나현주;박석채;장안수
    • Tuberculosis and Respiratory Diseases
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    • 제44권2호
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    • pp.298-308
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    • 1997
  • 연구배경 : 휴대용 PFMs에 의한 PEFR측정은 쉽고 간편하여 천식의 진단과 추적관찰에 널리 이용되고 있는데, 이들에 의해 측정된 PEFR성적이 얼마나 믿을만 할 것인지는 의문이다. 따라서 저자는 전산화폐기능검사기계인 pneumotachygraph를 기준으로 MPFM에 의한 PEFR측정의 정확도, 일치성, 정밀성을 검토하고자 하였다. 방 법 : 22례의 정상인과 17례의 경증 및 중등도의 천식환자를 대상으로 휴대용 PFMs인 MPFM로 PEFR을 측정하였고 전산화폐기능검사기계인 pneumotachygraph로 폐환기기능검사를 시행하였으며, 이중 정상인만을 대상으로 서로 다른 3일 동안 연속적으로 같은 방법으로 폐기능검사를 시행하여 다음과 같은 결과를 얻었다. 결 과 : 정상인과 환자군 모두에서 MPFM로 측정한 PEFR은 pneumotachygraph 에 의해 측정한 PEFR, $FEV_1$과 유의한 순상관관계에 있었다(for PEFR, r = 0.92, p < 0.001 ; for $FEV_1$, r = 0.78 ; p < 0.001). 정상인과 환자군 모두에서 MPFM로 측정한 PEFR은 pneumotachygraph로 측정한 PEFR과 평균 16.5L/min의 차이(측정된 실제 PEFR의 2.90%)를 보였고 정상인만을 대상으로 했을 때는 10.6L/min의 차이(측정된 실제 PEFR의 1.75%)를 보여 NAEP에서 추천한 정확도의 기준 10%이내로 높은 정확도를 나타냈다. 정상인과 환자군 모두에서 MPFM로 측정한 PEFR과 pneumotachygraph로 측정한 PEFR사이의 Bland-Altman방법에 의한 일치성은 회귀방정식을 이용해 교정했을 때 -71.5~+38.2L/min을 보였고 정상인만을 대상으로 했을 때는 -20.49~+9.49L/min을 보여, 정상인에서 연속 3 일간 얻은 개체내 일치성과 유사하였다. 정상인만을 대상으로 연속 3일간 MPFM로 측정한 PEFR과 pneumotachygrph에 의한 폐기능성적은 각각 횟수에 따라 유의한 차이가 없었고(p > 0.05), MPFM에 의한 PEFR의 CV는 $2.4{\pm}1.2%$로서 pneumotachygraph에 의한 $5.2{\pm}3.5%$보다 유의하게 작았다(p < 0.05). 결 론 : 이상의 성적으로 MPFM에 의해 측정한 PEFR은 전산화폐기능검사기계에 의한 폐기능성적과 다를 바 없는 좋은 성적을 측정할 수 있어서 기관지 천식환자의 폐기능상태의 변화양상을 추적관찰하는데 유용한 것으로 사료되었다.

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신경망이론에 의한 비중심T분포 확률계산 (Computation of Noncentral T Probabilities using Neural Network Theory)

  • 구선희
    • 한국정보처리학회논문지
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    • 제4권1호
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    • pp.177-183
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    • 1997
  • 비 중심t분포의 누적함수는 두 정규모집단에서 모평균의 동일성 검정에서 검정력 계산 및 모 평균에 대한 표준편차의 비에 대하여 신뢰구간을 계산할 때 요구된다. 본 논문에서는 비중심t분포의 누적함수 계산에 신경망 이론을 적용하였다. 신경망은 다 층 퍼셉트론이며 학습과정은 역전파 학습알고리즘이다. Fisher가 제시한 확률값과 신 경망이론에 의하여 계산한 결과를 비교하였다.

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모멘트 방법을 이용한 전기집진기의 집진 효율 (Collection Efficiency of Electrostatic Precipitator using Moment Method)

  • 정창훈;이규원
    • 한국대기환경학회지
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    • 제18권5호
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    • pp.345-353
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    • 2002
  • A study of polydispersed aerosol dynamics by Electrostatic Precipitator (ESP) was carried out. The log-normal particle size distribution was assumed and moment method was considered. In order to apply moment method in Deutsch-Anderson equation, Cunningham slip correction factor and Cochet's charge equation were simplified for certain range of particle size. The three parameters, which explain the particle size distribution, such as total number concentration, geometric mean diameter, and geometric standard deviation were considered to derive the analytic solution. The obtained solution was compared with available numerical results (Bai et al., 1995). The comparison of the numerical and analytic results showed a good agreement.

지역적 통계량을 이용한 고속 환경-광 가림 볼륨 가시화 (Fast Ambient Occlusion Volume Rendering using Local Statistics)

  • 남진현;계희원
    • 한국멀티미디어학회논문지
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    • 제18권2호
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    • pp.158-167
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    • 2015
  • This study presents a new method to improve the speed of high quality volume rendering. We improve the speed of ambient occlusion which is one of the global illumination techniques used in traditional volume visualization. Calculating ambient occlusion takes much time because it determines an illumination value of a sample by integrating opacities of nearby samples. This study proposes an improved method for this by using local statistics such as averages and standard deviations. We calculate local statistics for each volume block, a set of nearby samples, in pre-processing time. In the rendering process, we efficiently determine the illumination value by assuming the density distribution as a normal distribution. As the results, we can generate high quality images that combine ambient occlusion illumination with local illumination in real time.

On an Information Theoretic Diagnostic Measure for Detecting Influential Observations in LDA

  • Kim, Hea-Jung
    • Journal of the Korean Statistical Society
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    • 제25권2호
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    • pp.289-301
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    • 1996
  • This paper suggests a new diagnostic measure for detecting influential observations in two group linear discriminant analysis(LDA). It is developed from an information theoretic point of view using the minimum discrimination information(MDI) methodology. MDI estimator of symmetric divergence by Kullback(l967) is taken as a measure of the power of discrimination in LDA. It is shown that the effect of an observation over the power of discrimination is fully explained by the diagnostic measure. Asymptotic distribution of the proposed measure is derived as a function of independent chi-squared and standard normal variables. By means of the distributions, a couple of methods are suggested for detecting the influential observations in LDA. Performance of the suggested methods are examined through a simulation study.

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Comparisons of Probability and Statistics Education in Mathematics Textbooks in Korea High School

  • Lee, Sang-Bock
    • Journal of the Korean Data and Information Science Society
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    • 제15권3호
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    • pp.523-529
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    • 2004
  • In Korea, mathematics education has been changed according to the 7th national mathematics curriculum renovated by the Ministry of Education and Human Resources Development announcement in 1997. The education of probability and Statistics has been carried out as a part of this curriculum. We analyze and compare 3 kinds of mathematics textbooks for 10-12 grade students. Descriptions of random variable, sample variance and sample standard deviation, distribution of sample mean, and etc. which are on some textbooks, are misleaded in school education. We suggest the unbiased estimator of sample variance in textbooks and distributions of sample means with normal population assumption.

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샘플링 검사를 통한 경제적 공정 목표 값 결정에 관한 연구 (Determination of the Economical Target Value Through Sampling Inspectioni)

  • 이동철;윤덕균
    • 한국경영과학회지
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    • 제25권2호
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    • pp.67-76
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    • 2000
  • We consider the determinant of the most economical target value through the sampling inspection by two consecutive machines. The machine sequence is fixed as products have to be processed by machine 1 first and then by machine 2 next, In this paper we assume that if quality of a unit is lower than inspection lower specification limited then the goods is not accepted, otherwise it is accepted. And we assume that the quality characteristics is larger-the-better characteristics and its distribution is the normal distribution whose standard deviation is known. This paper ends up with an numerical example by using the total expected profit function model that consider the scales profits inspection costs and material costs. And we analyze the variation of the total expected profit by changing coefficients of the functions.

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Bit-map-based Spatial Data Transmission Scheme

  • OH, Gi Oug
    • 한국컴퓨터정보학회논문지
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    • 제24권8호
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    • pp.137-142
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    • 2019
  • This paper proposed bitmap based spatial data transmission scheme in need of rapid transmission through network in mobile environment that use and creation of data are frequently happen. Former researches that used clustering algorithms, focused on providing service using spatial data can cause delay since it doesn't consider the transmission speed. This paper guaranteed rapid service for user by convert spatial data to bit, leads to more transmission of bit of MTU, the maximum transmission unit. In the experiment, we compared arithmetically default data composed of 16 byte and spatial data converted to bitmap and for simulation, we created virtual data and compared its network transmission speed and conversion time. Virtual data created as standard normal distribution and skewed distribution to compare difference of reading time. The experiment showed that converted bitmap and network transmission are 2.5 and 8 times faster for each.

원전시설의 내진성능평가를 위한 입력지반운동의 최소개수 (Minimum Number of Input Ground-motions to Assess Seismic Performance of Nuclear Facilities)

  • 홍기증;최지혜;김현욱;주광호
    • 한국지진공학회논문집
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    • 제20권5호
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    • pp.341-349
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    • 2016
  • Currently, researches are being actively conducted in assessing seismic performance of nuclear facilities in USA and Europe. In particular, applying this technique of assessing seismic performance to design of isolation systems in nuclear power plants is being performed and then ASCE 4 Draft (2013) is being revised accordingly in the United States. In order to satisfy the probabilistic performance objectives described by seismic responses with certain confidence levels (ASCE 43, 2005), the probability distributions of these responses have to be defined. What is the minimum number of input ground-motions to obtain the probability distribution precise enough to represent the unknown actual distribution? Theoretical basis, for how to determine the minimum number of input ground-motions for given a logarithmic standard deviation to approximate the unknown actual median of the log-normal distribution within a range of error at a certain level of confidence, is introduced by Huang et al. (2008). However, the relationship between the level of confidence and the range of error is not stated in the previous study. In this paper, based on careful reviews on the previous work, the relationship between the level of confidence and the range of error is logically and explicitly stated. Furthermore, this relationship is also applied to derive the minimum number of input ground-motions in order to approximate the unknown actual logarithmic standard deviation. Several recommendations are made for determining the minimum number of input ground-motions in probabilistic assessment on seismic performance of facilities in nuclear power plants.