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A Study of Wind Turbine by Using ANSYS Program (ANSYS 프로그램을 이용한 풍력발전에 관한 연구)

  • Lee, Dal-Ho;Park, Jung-Cheul
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.11 no.5
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    • pp.565-571
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    • 2018
  • This paper designed the main blade in V-shape and tried to identify the design conditions by changing the main blade number and sub-blade number. Power output and power coefficient increased as main blade number increased. Sample 2 shows a 50% increase in power output compared to sample1. Sample 3 and sample4 increased by 92.8% and 114.7%, respectively. Sample 2 shows a 38.4% increase in power coefficient compared to sample1. Sample 3 and sample4 increased by 92.3% and 107.7%, respectively. Power output and power coefficient increased as sub-blade number increased. Sample 6 shows a 33.3% increase in power output compared to sample 5 and Sample 7 increased by 42.1%. Compared to sample5, efficiency increased by 35.3% for sample 5 and 47.1% for sample 7. The highest power output and power coefficient were measured when main blade and sub-blade were each 30 number. Sample 8 increased power output by 5.6% and power efficiency by 3.7% compared to sample 4. Compared to sample 7, sample 8 increased power efficiency by 12% and power output by 17.3%.

An Economic Design of the Chart with Variable Sample Size Scheme

  • Park, Chang-Soon;Ji, Seon-Su
    • Journal of the Korean Statistical Society
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    • v.23 no.2
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    • pp.403-420
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    • 1994
  • An economic design of the $\bar{X}-R$ chart using variable sample size (VSS) scheme is proposed in this paper. In this design the sample size at each sampling time changes according to the values of the previous two sample statistics, sample mean and range. The VSS scheme uses large sample if the sample statistics appear near inside the control limits and smaller sample otherwise. The set of process parameters, such as the sampling interval, control limits and the sample sizes, are chosen to minimize the expected cost per hour. The efficiency of the VSS scheme is compared to the fixed sample size one for cases where there is multiple of assignable causes. Percent reductions of the expected cost in the VSS design are calculated for some given sets of cost parameters. It is shown that the VSS scheme improves the confidence of the procedure and performs statistically better in terms of the number of false alarms and the average time to signal, respectively.

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Effects of Kamigyemyoungsan and Each Compositive Herbs on the Intravascular Coagulation and Subcutaneous Hematoma in Rats (加味鷄鳴散 및 그 構成藥物이 白鼠의 瘀血病態模型에 미치는 影響)

  • Ji, Sun-Young;Jung, Dae-Gyu
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.10 no.1
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    • pp.1-38
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    • 1997
  • This study was performed to investigate the effects of Kamigyemyoungsan and each compositive herbs on the intravascular coagulation and subcutaneous hematoma. The intravascular coagulation was induced by the injection of endotoxin into the caudal vein of the rats. These rats were treated with endotoxin after administering orally extracts of Kamigyemyoungsan and each compositive herbs. Then the number of platelet, prothrombin time, the concentration of fibrinogen and FDP(fibrinogen degration product), hematocrit and RBC and WBC were measured. The subcutaneous hematoma was induced by the subcutaneous injection of the autologous whole blood to produce clotting in situ in rats. Then the extracts of Kamigyemyoungsan and each compositive herbs were administered orally. The lesions were then dissected and observed. The results were obtained as follows ; 1. The number of platelets of the trial groups was increased as compared with the control group, and revealed significance in sample Ⅰ. 2. The concentration of fibrinogen of the trial groups was increased as compared with the control group, and revealed significance in sample Ⅰ, sampleⅡ and sample Ⅴ. 3. The prothrombin time was shortened significantly in the trial groups, except sampleⅡ and sampleⅣ as compared with the control group. 4. The concentration of FDP decreased in the trial groups, and revealed significance in sample Ⅰ and sample Ⅵ as compared with the control group. 5. The hematocrit significantly increased in sample Ⅰ, sampleⅢ and sample Ⅵ as compared with the control group. 6. The number of RBC significantly increased in sample Ⅵ only as compared with the control group. 7. The number of WBC significantly increased in the trial groups, except sampleⅣ and sample Ⅵ as compared with the control group. 8. Histologically, the lesions in the trial groups showed significantly thinner fibroblastic neomembrane than the control group, except sampleⅢ. According to the above results, it is considered that Kamigyemyoungsan and each compositive herbs have inhibitive effects on the thrombosis and the fibroblastic neomembrane development. Therefore, it seems to be applicable to the diseases related to thrombosis and hematoma.

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Model Classification of Quality Statistics Using Block Repeated Measures (블록 반복측정을 이용한 품질통계 모형의 유형화)

  • Choi, Sung-Woon
    • Journal of the Korea Safety Management & Science
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    • v.9 no.3
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    • pp.165-171
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    • 2007
  • Dependent models in quality statistics are classified as serially autocorrelated model, multivariate model and dependent sample model. Dependent sample model is most efficient in time and cost to obtain samples among the above models. This paper proposes to implement parametric and nonparametric models into production system depended on demand pattern. Nonparametric models have distribution free and asymptotic distribution free techniques. Quality statistical models are classified into two categories ; the number of dependent sample and the type of data. The type of data consists of nominal, ordinal, interval and ratio data. The number of dependent sample divides into 2 samples and more than 3 samples.

Self-adaptive testing to determine sample size for flash memory solutions

  • Byun, Chul-Hoon;Jeon, Chang-Kyun;Lee, Taek;In, Hoh Peter
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.6
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    • pp.2139-2151
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    • 2014
  • Embedded system testing, especially long-term reliability testing, of flash memory solutions such as embedded multi-media card, secure digital card and solid-state drive involves strategic decision making related to test sample size to achieve high test coverage. The test sample size is the number of flash memory devices used in a test. Earlier, there were physical limitations on the testing period and the number of test devices that could be used. Hence, decisions regarding the sample size depended on the experience of human testers owing to the absence of well-defined standards. Moreover, a lack of understanding of the importance of the sample size resulted in field defects due to unexpected user scenarios. In worst cases, users finally detected these defects after several years. In this paper, we propose that a large number of potential field defects can be detected if an adequately large test sample size is used to target weak features during long-term reliability testing of flash memory solutions. In general, a larger test sample size yields better results. However, owing to the limited availability of physical resources, there is a limit on the test sample size that can be used. In this paper, we address this problem by proposing a self-adaptive reliability testing scheme to decide the sample size for effective long-term reliability testing.

Required Sample Size for Estimating Litter Mass in Northern Hardwood Forests, New Hampshire, USA (미국 뉴햄프셔주 낙엽활엽수림에서 낙엽량 측정을 위한 최소 필요 표본수)

  • Bae, Kikang
    • Korean Journal of Environmental Biology
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    • v.32 no.3
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    • pp.211-215
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    • 2014
  • In order to accurately estimate the litter mass, we evaluated the required sample sizes across 13 chronosequence stands for five years (1994~1996, 2003~2004) in northern hardwood forests in New Hampshire, USA. It was found that the number of required litter traps in our stands (0.25~0.5 ha) within ${\pm}10%$ of the sample mean was appeared to be similar or higher than the 15 litter traps installed in this study. Notably, in 1994 and 1995, the number of required litter trap was twice higher than the 15 litter traps. Further, within ${\pm}20%$ of the sample mean, the number of required litter traps was less than 10 across all 13 stands for five years, which indicates that we can reduce the sample size. Precisely, the number of sample size had increased in stands with steep and high elevation, but no relations with stand age across 13 stands were observed. Based on these results, we suggest that it is important to sample litter mass for several years, in order to determine the number of appropriate sample size, and stands with steep and high elevation may need more litter traps.

Quantitative Counting of Bifidobacterium spp. in a Sample Mixed with Lactobacillus acidophilus

  • Park, Young-Min;So, Jae-Seong
    • Journal of Microbiology and Biotechnology
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    • v.8 no.2
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    • pp.182-184
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    • 1998
  • PCR was used for quantitative counting of Bifidobacterium spp. in a sample mixed with Lactobacillus acidophilus using two primer sets; one set for universal priming and the other set for Bifidobacterium specific priming. DNA products from two independent PCRs with DNA extracted from the mixed sample were found to be easily distinguishable from each other by agarose gel electrophoresis. The concentrations of PCR products correlated with the total number of bacteria and with the number of Bifidobacterium spp. present in the sample.

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THE BRIGHT PART OF THE LUMINOSITY FUNCTION FOR HALO STARS

  • Lee, Sang-Gak
    • Journal of The Korean Astronomical Society
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    • v.28 no.2
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    • pp.139-146
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    • 1995
  • The bright part of the halo luminosity function is derived from a sample of the 233 NLTT propermotion stars, which are selected by the 220 km/ see of cutoff velocity in transverse to rid the contamination by the disk stars and corrected for the stars omitted in the sample by the selection criterion. It is limited to the absolute magnitude range of $M_v=4-8$, but is based on the largest sample of halo stars up to now. This luminosity function provides a number density of $2.3{\cdot}10^{-5}pc^{-3}$ and a mass density of $2.3{\cdot}10^{-5}M_{o}pc^{-3}$ for 4 < $M_v$ < 8 in the solar neighborhood. These are not sufficient for disk stability. The kinematics of the sample stars are < U > = - 7 km/sec, < V > = - 228 km/sec, and < W > = -8 km/sec with (${\sigma_u},{\sigma_v},{\sigma_w}$) = (192, 84, 94) km/sec. The average metallicity of them is [Fe/H] = $- 1.7{\pm}0.8$. These are typical values for halo stars which are selected by the high cutoff velocity. We reanalyze the luminosity function for a sample of 57 LHS proper-motion stars. The newly derived luminosity function is consistent with the one derived from the NLTT halo stars, but gives a somewhat smaller number density for the absolute magnitude range covered by the LF from NLTT stars. The luminosity function based on the LHS stars seems to have a dip in the magnitude range corresponding to the Wielen Dip, but it also seems to have some fluctuations due to a small number of sample stars.

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Effects of Panax ginseng Radix herb-acupuncture on c-fos expression in the hippocampus of ethanol-intoxicated Sprague-Dawley rats (인삼(人蔘) 약침(藥鍼)이 에탄올 중독 흰쥐의 해마에서 c-fos 생성에 미치는 영향)

  • Kim, Min-soo;Lee, Eun-yong
    • Journal of Acupuncture Research
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    • v.20 no.3
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    • pp.131-140
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    • 2003
  • Objective : The purpose of this study is to investigate the effect of Panax ginseng Radix herb-acupuncture on c-fos expression in each area of the hippocampus of acutely ethanol-intoxicated rats. Methods : Twenty-four male Sprague-Dawley tats were divided into untreated(normal), ethanol-treated(control), Panax ginseng Radix-treated(sample A), ethanol-and Panax gingseng Radix-treated(sample B) groups. Each group was evaluated by the changes of c-fos-positive neurons in each area of the hippocampus by using and image analyzer and microscope. Results : 1. In the CA1 area, the number of c-fos-positive neurons in the control group was diminished compared with the normal group. The number of c-fos-positive neurons in the sample B group had no marked difference from the control group. 2. In the CA2-3 area, the number of c-fos-positive neurons in the control group was diminished compared with the normal group, The number of c-fos-positive neurons in the sample B group was increased compared with the control group. 3. In the Dentate gyrus area, the number of c-fos-positive neurons in the control group was diminished compared with the normal group. The number of c-fos-positive neurons in the sample B group was increased compared with the control group. Conclusions : These results indicate that, c-fos expression in each area of the hippocampus was reduced in ethanol-intoxicated group. Treatment of Panax ginseng Radix herb-acupuncture increased this diminution. Panax ginseng Radix could be able to effect on the prevention of the amnesia and learning disability in alcoholism.

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Two-stage Sampling for Estimation of Prevalence of Bovine Tuberculosis (이단계표본추출을 이용한 소결핵병 유병률 추정)

  • Pak, Son-Il
    • Journal of Veterinary Clinics
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    • v.28 no.4
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    • pp.422-426
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    • 2011
  • For a national survey in which wide geographic region or an entire country is targeted, multi-stage sampling approach is widely used to overcome the problem of simple random sampling, to consider both herd- and animallevel factors associated with disease occurrence, and to adjust clustering effect of disease in the population in the calculation of sample size. The aim of this study was to establish sample size for estimating bovine tuberculosis (TB) in Korea using stratified two-stage sampling design. The sample size was determined by taking into account the possible clustering of TB-infected animals on individual herds to increase the reliability of survey results. In this study, the country was stratified into nine provinces (administrative unit) and herd, the primary sampling unit, was considered as a cluster. For all analyses, design effect of 2, between-cluster prevalence of 50% to yield maximum sample size, and mean herd size of 65 were assumed due to lack of information available. Using a two-stage sampling scheme, the number of cattle sampled per herd was 65 cattle, regardless of confidence level, prevalence, and mean herd size examined. Number of clusters to be sampled at a 95% level of confidence was estimated to be 296, 74, 33, 19, 12, and 9 for desired precision of 0.01, 0.02, 0.03, 0.04, 0.05, and 0.06, respectively. Therefore, the total sample size with a 95% confidence level was 172,872, 43,218, 19,224, 10,818, 6,930, and 4,806 for desired precision ranging from 0.01 to 0.06. The sample size was increased with desired precision and design effect. In a situation where the number of cattle sampled per herd is fixed ranging from 5 to 40 with a 5-head interval, total sample size with a 95% confidence level was estimated to be 6,480, 10,080, 13,770, 17,280, 20.925, 24,570, 28,350, and 31,680, respectively. The percent increase in total sample size resulting from the use of intra-cluster correlation coefficient of 0.3 was 22.2, 32.1, 36.3, 39.6, 41.9, 42.9, 42,2, and 44.3%, respectively in comparison to the use of coefficient of 0.2.