• 제목/요약/키워드: effective sample size

검색결과 370건 처리시간 0.024초

미숙아에 대한 감각자극 효과에 관한 메타분석 (Meta-analysis on the Effects of Sensory Stimulation of Preterm Infants)

  • 김은주
    • Child Health Nursing Research
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    • 제9권2호
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    • pp.131-139
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    • 2003
  • Purpose: This study was meta-analysis study that it was to analyze the effect of sensory stimulation on preterm infants. Method: The sample of this study is 18 researches of selected by criteria. The conclusion of study was that sensory stimulation of preterm infants is effective. Result: Most large effect size was Katz(1991)'s study(d=1.96), small effect size was Caine(1991), s(d=0.37). Especially multimodal sensory stimulation(d=1.2) was more effective than unimodal sensory stimulation(0.53). Also behavioral variable of preterm infans was most sensitivity indicator. Conclusion: According to the result, the study on sensory stimulation should be research according to the gestational age and birth weight of preterm infants. In addition, the feasible sensory intervention should be develop.

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나노 기술을 이용한 기능성 우유 및 유제품의 개발 연구 (Development of Functional Milk and Dairy Products by Nanotechnology)

  • 곽해수
    • Journal of Dairy Science and Biotechnology
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    • 제23권1호
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    • pp.27-37
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    • 2005
  • The development of functional foods started booming from several years ago in the world. The size of functional materials are in the range of micrometer level. This size can be much smaller into nanometer level to be more effective. We face some problems from the materials, such as flavor, taste, color, viscosity, etc. in functional materials. The problems can be solved by micro / nanoencapsulation technique. This paper showed some results of the research related on the technique for functional milks and dairy products. The nono / microcapsules are the form of liquid instead of solid. Coating materials used were fatty acid esters, and core materials were lactase, iron, ascorbic acid. isoflavone, and chitooligosaccharide. The ranges of capsules are from 100 nm to 200 ${\mu}$m. The sample milks added nano/microcapsules were homogeneous and prevented the defects of core materials. It was observed that nano / microcapsules in milk and dairy products were effective as functional material without defaults. It was indicated that targeted functional foods can be developed further in various foods by nanotechnology.

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초고속 액체크로마토그래피를 이용한 고춧가루의 capsaicinoids 분석 (Determination of capsaicinoids in red pepper powder using ultra high performance liquid chromatography)

  • 남궁배;이윤열;하재호
    • 분석과학
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    • 제26권4호
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    • pp.256-261
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    • 2013
  • 고춧가루의 매운맛을 나타내는 capsaicinoids인 capsaicin과 dihydrocapsaicin을 초고속액체 크로마토그래피로 간편하게 측정하기 위하여 고춧가루의 입도, 추출시간에 따른 추출율 비교하고 환류추출법과 가열블록법을 비교하였다. 환류추출법의 경우 3 시간 추출하는 것이 효율적이었으며 capsaicinoids 추출율은 덜 매운 고춧가루의 경우 입도가 고울수록 높았으나 매운 청량고추의 경우는 추출율이 입도에 영향을 덜 받았다. 시료량을 달리한 경우 용매의 사용을 동일하게하면 시료를 적게 사용하는 것이 추출율이 높았다. 환류추출법으로 3시간 추출한 것은 가열블록법으로 1 시간 추출한 것에 비하여 추출효율이 3-9% 높았으나 품질관리의 목적인 경우 신속간편 방법인 가열블록법으로 고춧가루의 capsaicinoids를 측정하는 것이 가능하였다.

사회조사에서 표본의 왜곡과 가중치 보정의 결과: 18개 사례연구 (Sample Distortion in Social Surveys and Effects of Weighting Adjustment: A Study of 18 Cases)

  • 허명회;윤영아;이용구
    • 한국조사연구학회지:조사연구
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    • 제5권2호
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    • pp.31-48
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    • 2004
  • 우리나라에서 수행되는 사회조사들은 대부분 지역, 성과 나이대를 고려한 할당추출법(quota sampling)을 사용하며 전화번호부를 표집틀로 한 전화조사가 주류를 이룬다. 이러한 표본들이 지역, 성, 나이대 외의 인구사회적 속성 측면에서 모집단을 잘 대표하는지, 아니면 일정 방향으로 기울어져 있는지를 검토할 필요가 있다. 또한 표본 편향을 줄이기 위하여 가중법을 적용하는 경우 조사 결과에 어떤 영향을 주는가를 살펴볼 필요가 있다. 이 연구는 2000년부터 2003년 사이에 전화조사로 수행된 18례의 사회조사에서 표본의 모집단 대표성을 지역, 성. 나이대, 학력과 직업 측면에서 살펴본 것이다. 사례들을 종합한 결과, 지역, 성과 나이대를 보정한다고 하더라도 표본들에서 고학력자와 가정주부가 과다하고 반면 저학력자와 자영업/블루칼러, 화이트칼러가 과소한 것으로 나타났다. 학력과 직업에서의 왜곡은 많은 사회조사에서 본조사 항목의 편향을 초래할 가능성이 있다. 반복비례가중법으로 이러한 표본왜곡을 시정하여 보았더니 본조사 항목에서 원조사 결과와 상당한 차이가 나타났다. 가중치 보정을 하면 유효표본크기가 감소하는 결과가 초래되는데, 각 조사가 명목적으로 제시하는 일정 수준의 오차한계를 지키기 위해서는 현재보다 20~4-% 정도 표본을 크게 해야 한다는 결론을 얻었다.

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Geometric charts with bootstrap-based control limits using the Bayes estimator

  • Kim, Minji;Lee, Jaeheon
    • Communications for Statistical Applications and Methods
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    • 제27권1호
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    • pp.65-77
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    • 2020
  • Geometric charts are effective in monitoring the fraction nonconforming in high-quality processes. The in-control fraction nonconforming is unknown in most actual processes; therefore, it should be estimated using the Phase I sample. However, if the Phase I sample size is small the practitioner may not achieve the desired in-control performance because estimation errors can occur when the parameters are estimated. Therefore, in this paper, we adjust the control limits of geometric charts with the bootstrap algorithm to improve the in-control performance of charts with smaller sample sizes. The simulation results show that the adjustment with the bootstrap algorithm improves the in-control performance of geometric charts by controlling the probability that the in-control average run length has a value greater than the desired one. The out-of-control performance of geometric charts with adjusted limits is also discussed.

퇴적 목분의 훈소층 전파에 관한 연구 (A Study on the Smoldering Zone Spread of the Heaped Saw-Dust)

  • 정국삼;강민호
    • 한국안전학회지
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    • 제12권3호
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    • pp.90-96
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    • 1997
  • This paper was concerned with temperature aspect in the smoldering time of the accumulated each saw-dust sample of larch, oregon, aromatic trees which was formed with heaped cone-shape. The smoldering time and temperature of each sample was measured under the wind velocity of 0.10~0.15 m/s and circumstance relative humidity of 60%. As a result, the very lowest heat beginning temperature was detected in aromatic. The effective smoldering phenomena in the sample were detected when the larch saw-dust of [-20+40mesh] and the aromatic saw-dust of [-40+50mesh, -50+60mesh]. Finally the larger a particle size of saw-dust was the better a smoldering time was short. Also, it showed more increasing temperature above $70^{\circ}C$in the smoldering reaction.

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바이오용 마이크로 핀의 제작에 관한 연구 (A study on Manufacturing of Micro Dotting Pin)

  • 이영수;김광순;김병희
    • 산업기술연구
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    • 제23권A호
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    • pp.21-27
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    • 2003
  • The bio-micro pin is usually used for biochemistry analysis. The capability of manufacturing the micro-pin and array with effective and low-cost way is very important to developers. The micro-pin is composed of "sample channel" putting liquid into already fixed volume, "flat tip" having connection with printing quantity, and "head part" for preventing it from rotation of pin in the holder. We analyzed out printing variation in accordance with shape and tip size of the micro-pin point channel, In this study, we suggested the manufacturing progress and shape demand condition of the micro-pin which could put $0.2{\mu}{\ell}$-biochemistry material into the sample volume, and will be able to produce the micro-pin which can put $10n{\ell}$-biochemistry material into the sample volume in the future.

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산화성물질의 화학적 위험성 평가 (Chemical Risk Assessment of Oxidizing Substances)

  • 정국삼
    • 한국안전학회지
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    • 제8권1호
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    • pp.35-46
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    • 1993
  • This paper was concerned with the risk assessment about oxidizing substances as dangerous goods by burning test method. The sample. which was formed with the heaped cone-shape. was composed of solid oxidant and sawdust. The burning time of each sample was measured under the following various conditions circumstance temperature. mixing ratio of oxidizing substance and sawdust. particle size of sawdust and kinds of sawdust. As a results. the effective combustibility was gained when the sawdust content was 20∼30 wt.% in the sample and the lauan with -30+50 mesh was used. But. although the circumstance temperature increased. burning efficiency of the samples wet$.$e not affect by it. Finally. the average burning times were obtained by considering the weighting factors related on the mixing ratio and the circumstance temperature. And then. it were compared with the combustion risk level and the effects of cation and anion of oxidizing substances as dangerous goods.

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Size Distribution and Temperature Dependence of Magnetic Anisotropy Constant in Ferrite Nanoparticles

  • Yoon, Sunghyun
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2012년도 자성 및 자성재료 국제학술대회
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    • pp.104-105
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    • 2012
  • The temperature dependence of the effective magnetic anisotropy constant K(T) of ferrite nanoparticles is obtained based on the measurements of SQUID magnetometry. For this end, a very simple but intuitive and direct method for determining the temperature dependence of anisotropy constant K(T) in nanoparticles is introduced in this study. The anisotropy constant at a given temperature is determined by associating the particle size distribution f(r) with the anisotropy energy barrier distribution $f_A(T)$. In order to estimate the particle size distribution f(r), the first quadrant part of the hysteresis loop is fitted to the classical Langevin function weight-averaged with the log?normal distribution, slightly modified from the original Chantrell's distribution function. In order to get an anisotropy energy barrier distribution $f_A(T)$, the temperature dependence of magnetization decay $M_{TD}$ of the sample is measured. For this measurement, the sample is cooled from room temperature to 5 K in a magnetic field of 100 G. Then the applied field is turned off and the remanent magnetization is measured on stepwise increasing the temperature. And the energy barrier distribution $f_A(T)$ is obtained by differentiating the magnetization decay curve at any temperature. It decreases with increasing temperature and finally vanishes when all the particles in the sample are unblocked. As a next step, a relation between r and $T_B$ is determined from the particle size distribution f(r) and the anisotropy energy barrier distribution $f_A(T)$. Under the simple assumption that the superparamagnetic fraction of cumulative area in particle size distribution at a temperature is equal to the fraction of anisotropy energy barrier overcome at that temperature in the anisotropy energy barrier distribution, we can get a relation between r and $T_B$, from which the temperature dependence of the magnetic anisotropy constant was determined, as is represented in the inset of Fig. 1. Substituting the values of r and $T_B$ into the $N{\acute{e}}el$-Arrhenius equation with the attempt time fixed to $10^{-9}s$ and measuring time being 100 s which is suitable for conventional magnetic measurement, the anisotropy constant K(T) is estimated as a function of temperature (Fig. 1). As an example, the resultant effective magnetic anisotropy constant K(T) of manganese ferrite decreases with increasing temperature from $8.5{\times}10^4J/m^3$ at 5 K to $0.35{\times}10^4J/m^3$ at 125 K. The reported value for K in the literatures is $0.25{\times}10^4J/m^3$. The anisotropy constant at low temperature region is far more than one order of magnitude larger than that at 125 K, indicative of the effects of inter?particle interaction, which is more pronounced for smaller particles.

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C형간염에 대한 한약의 치료효과 : 체계적 문헌고찰과 메타분석 (Effect of Herbal Medicine on Hepatitis C: a Systematic Review and Meta-analysis)

  • 강은진;김경림;김경민
    • 대한한방내과학회지
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    • 제40권3호
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    • pp.312-330
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    • 2019
  • Objectives: The present study aimed to provide clinical evidence on the effect of herbal medicine on the treatment of hepatitis C using a systematic review and meta-analysis of randomized controlled trials (RCTs). Methods: This study included RCTs that verified the effects of herbal medicine for the treatment of hepatitis C. A literature search of English, Chinese, and Korean databases was performed, and the selected literature was assessed to investigate the risk of bias. Results: The analysis included 14 RCTs. The total effective rate was the most commonly used outcome measure. The meta-analysis revealed that the total effective rate and total bilirubin difference were higher and that the recurrent rate was lower in the herbal medicine group than in the western medicine group (RR: 1.20, 95% CI: 1.06-1.35, p=0.003, I2=52; MD: 0.52, 95% CI: -0.62 to 1.66, p=0.37, I2=0; RR: 0.35, 95% CI: 0.11-1.09, p=0.07, I2=0). The included RCTs had relatively poor quality and a small sample size. Conclusion: Treatment with herbal medicine was found to be partially effective in treating hepatitis C. The included RCTs had relatively poor quality and a small sample size. This study can serve as a foundation for further clinical studies on the development of treatment methods for hepatitis C based on herbal medicine.