• Title/Summary/Keyword: Distribution of sample mean

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Evaluation of Percolated Water Quality of Paddy Fields Using Nonparametric Test (비모수검정을 이용한 논침투수 수질의 평가)

  • Oh, Seung-Young;Kim, Jin-Soo;Oh, Kwang-Young
    • Journal of The Korean Society of Agricultural Engineers
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    • v.47 no.2
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    • pp.99-110
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    • 2005
  • Characteristics of concentrations of total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) pollutant in percolated water at four paddy field sites (Soro, Odong, Munui, and Boeun) were investigated by a nonparametric test. Percolation rate measurement and percolated water sampling were taken during irrigation periods at $5{\sim}10$ day intervals. The normality of percolation rate and pollutant concentrations were examined using histogram, boxplot, and the Kolmogorov-Smirnov (K-S) test. Pollutant concentrations in percolated water showed positively skewed distribution. The median concentrations of pollutant were 1.91 mg/L for TN, 0.021 mg/L for TP, and 6.6 mg/L for COD, which were lower than its arithmetic mean concentrations by $35\%$ for TN, $36\%$ for TP, and $13\%$ for COD. The median concentrations of TN and TP differed significantly among sample sites according to the Kruskal-Wallis test. However, median concentrations were not significantly different among month except for TN and TP of Soro and COD of Odong. The percolation load of pollutants during irrigation periods in the study area were estimated at $3.12{\sim}7.75\;kg/ha$ for TN, $0.033{\sim}0.155\;kg/ha$ for TP, and 10.7 kg/ha for COD, which were much lower than respective values reported in Japan.

Economic Design of $\bar{X}$-Control Charts with Warning Limits under Weibull Failure Model (와이블 고장모형 하에서 경고한계를 고려한 $\bar{X}$ 관리도의 경제적 설계)

  • Jeong, Dong-Wook;Lee, Joo-Ho
    • Journal of Korean Society for Quality Management
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    • v.40 no.2
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    • pp.186-198
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    • 2012
  • Since Duncan(1956) first proposed an economic design of $\bar{X}$-control charts, most of the succeeding works on economic design of control charts assumed the exponential failure model like Duncan. Hu(1984), however, assumed a more versatile Weibull failure model to develop an economic design of $\bar{X}$-control charts and Banerjee and Rahim(1988) further improved Hu's design by changing the assumption of fixed-length sampling intervals to variable-length ones. In this article we follow the approach of Banerjee and Rahim(1988) but include a pair of warning limits inside the control limits in order to search for a failure without stopping the process when the sample mean falls between warning and control limits. The computational results indicate that the proposed model gives a lower cost than Banerjee and Rahim's model unless the early failure probability of a Weibull distribution is relatively large. The reduction in cost is shown to become larger as the cost of production loss outweighs the cost of searches for a failure.

Factors Affecting Employee Loyalty in Railway Rolling Stock Maintenance Companies in Thailand

  • LIEOPHAIROT, Ratchaphong;ROJNIRUTTIKUL, Nuttawut
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.10
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    • pp.115-127
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    • 2022
  • The study's goal was to investigate the levels of employee loyalty (EL) in two Thai railway rolling stock maintenance (RRSM) companies. Simple random sampling was used to obtain a final sample of 118 individuals from October 2021 through December 2021. The research instrument was a questionnaire with an expert IOC value between 0.67 to 1.00 and a questionnaire reliability Alpha (𝛼) average value of 0.82. Descriptive statistics included the mean and standard deviation (SD). SPSS for Windows Version 21 and Multiple Regression Analysis (MRA) was used for the analysis. Results showed that the 118 employee's overall perceptions of their RRSM employers' motivating factors, human resource management, satisfaction, and loyalty were high. HRM's performance evaluation had the most significant overall influence on EL. Moreover, from the analysis of the five EL questionnaire items, the most influential item was the employee's income as a contributing factor to their EL. This was followed by the suitability of their work. Also, it seems the employees had a high level of loyalty to their firms even if a better offer of more money was made. They also indicated a high level of pride in their respective firms.

Implementation of contextualized, emergency management cognitive aids in a periodontics clinic

  • Siemens, Mikaela J.;Rice, Andi N.;Jensen, Trenton F.;Simmons (Muckler), Virginia C.
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.21 no.3
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    • pp.227-236
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    • 2021
  • Background: Emergencies in outpatient clinics are rare. However, potentially catastrophic events can be challenging to manage due to a variety of factors, including limited equipment and staff. The purpose of this quality improvement project was to improve the staff knowledge and familiarity with critical performance elements for emergencies encountered in the setting of a periodontics clinic. Methods: Emergency cognitive aids tailored to the clinic's resources were created for anaphylaxis, airway obstruction, and sublingual hemorrhage. The project pre-post-test repeated measures design evaluated the effectiveness of cognitive aids using a combination of hands-on simulation, written knowledge assessments, and self-efficacy surveys. Training sessions and simulations were provided to the clinic's existing care teams made up of a periodontist and two dental assistants with an anesthetist who was present for simulations involving sedation. Due to the small sample size (N = 14) and non-normal distribution, all metrics were evaluated using non-parametric statistics. Results: Significant improvements were found in knowledge assessment (-2.310, P = 0.021) and self-efficacy (-2.486, P = 0.013) scores when retention after a training session before and after the introduction of cognitive aid was compared. The mean simulation scores and times improved steadily or reached maximum scores during the project progression. Conclusion: Training sessions before and after cognitive aid introduction were effective in improving knowledge, self-efficacy, and simulation performance. Future projects should focus on validating the process for creating contextualized cognitive aids and evaluating the effectiveness of these cognitive aids in larger samples.

A Study on the Application of Swedish Group Home for the Elderly with Dementia in Korea (치매노인을 위한 스웨덴 그룹홈의 우리나라 적용가능성 연구)

  • 최정신;김대년;조명희;권오정
    • Journal of the Korean Home Economics Association
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    • v.38 no.5
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    • pp.153-166
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    • 2000
  • The purpose of this study was to determine the extent to which Swedish group home for elderly people with dementia coed be applied to the situation in Korea. One hundred and ninety six Korean subjects, responsible for supporting a member of their family afflicted with such an illness in their own homes, comprised the sample population for this study. Data was collected using questionnaires. frequency distribution, mean, and chi-square tests were used to analyze the data. The results of this study indicated a great possibility for adapting these kinds of group home in Korea. The respondents showed positive opinions with the basic concepts and space plans of Swedish group homes excepts for some details, like the number of residents per room. The respondents felt that a group home for dementia with the fellowing features was desirable : smart scale, single-family detached house,3-4 rooms, a total of 6-8 residents, managed by non-profit organizations or the government at a monthly cost of 530,000-1,000,000 won. In order to develope these group homes for dementia people in Korea, political assistance, combined with economic support, are strongly needed. The successful establishment of a group home will contribute not only to the welfare of elderly people with dementia but to their families as well.

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A Survey for Globular Clusters in Cosmic Void Galaxies

  • Sohn, Jubee;Lee, Myung Gyoon;Ko, Youkyung;Lim, Sungsoon;Park, Hong Soo
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.45.2-45.2
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    • 2014
  • We carry out the first survey for globular clusters (GCs) of three galaxies in cosmic voids using Hubble Space Telescope (HST) Advanced Camera for Survey archival F606W and F814W images. While all sample galaxies are classified as early-type galaxies based on ground-based imaging, the high resolution HST images reveal that they are actually spiral galaxies. We identify the point sources with red colors typical for GCs as GC candidates in the color-magnitude diagrams. As a result, we find a significant number of GC candidates. The spatial and radial distribution of GCs show central concentration on each galaxy region. Their mean colors are similar to that of the Milky Way and M31 GCs. The void GCs are somewhat bluer by, and than cluster and field GCs in early-type galaxies with similar luminosity to our samples, but the discrepancy is not significant. We also estimate the specific frequencies of GCs in these galaxies and the values are consistent with those in field and cluster galaxies with similar luminosity. From these results, we suggest that the formation process of void GCs is similar to that of GCs in other environments. The further implications will be discussed.

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Studies on the Hematology and Blood Chemistry of Korean Cattle Part I. Studies on the Hematology of Korean Cattle (한국성우(韓國成牛)의 혈액학치(血液學値) 및 혈액화학치(血液化學値)에 관한 연구(硏究) 제1보(第一報) 한국성우(韓國成牛)의 혈액학치(血液學値)에 관한 연구(硏究))

  • Cheong, Chang Kook
    • Korean Journal of Veterinary Research
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    • v.5 no.1
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    • pp.61-96
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    • 1965
  • Observations were made on the blood picture of total 196 heads of healthy Korean cattles, including 98 males and 98 females in the purpose of determination of hematological values and its sex difference, and seasonal variations during one year period from December 1963 to November 1964. The blood sampling were scheduled by random in four different seasons and the sample size of both sex included in each season were designated to be same size. The ranges, averages or mean values of the erythrocytes, hemoglobin, hematocrit, mean corpuscular hemoglobin concentration, total white blood cell count and differential count were determined in this studies and their respective standard deviation, standard error of means, sex defferences and seasonal variations were as follows; 1. The erythrocyte count of male showed a range of $5.0{\times}10^6/c.mm$ to $8.75{\times}10^6/c.mm$ with a mean of $6.5{\pm}0.096{\times}10^6/c.mm$. Female showed a range of $5.0{\times}10^6/c.mm$ to $8.30{\times}10^6/c.mm$, with a mean of 6. $131{\pm}0.078{\times}10^6/c.mm$. There was a highly significant sex difference and seasomal variation was not found to be significant. 2. The hemoglobin value of male showed a range of 9.0g/100cc. to 14.5g/100cc. with a mean of $11.074{\pm}0.143g/100cc$. Female showed a range of 9.0g/100cc to 13.0g/100cc. with a mean of $10.745{\pm}0.034g/100cc$. There was a highly significant sex difference and seasonal variation was not found to be significant. 3. The hematocrit value of male showed a range of 28% to 45% and with a mean of $34.867{\pm}0.468%$. Female showed a range of 28% to 42% with a mean of $32.888{\pm}0.322%$. There was a highly significant sex difference and seasonal variation was not found to be significant. 4. The mean corpuscular hemoglobin of male showed a range of 14.4rr. to 19.6rr. with a mean of $17.1{\pm}0.112rr$. Female showed a range of 14.7rr. to 19.5rr. with a mean of $17.6{\pm}0.113rr$. 5. The mean corpusular volume of male showed a range of $42.5{\mu}^3$ to $62.2{\mu}^3$ with a mean of $53.9{\pm}0.419{\mu}^3$, Female showed a range of $44.2{\mu}^3$ to $60.0{\mu}^3$ with a mean of $53.8{\pm}0.375{\mu}^3$. 6. The mean corpuscular hemoglobin concentration of male showed a range of 28.1 % to 34.9% with a mean of $31.4{\pm}0.161%$. Female showed a range of 28.0% to 34.9% with a mean of $30.9{\pm}0.169%$. 7. The total leucocyte count of male showed a range of 4,000/c.mm to 13,100/c.mm. with a mean of $9,338{\pm}218.23/c.mm$. Female showed a range of 4,000/c.mm. to 14,000/c.mm. with a mean of $9,338{\pm}235.90/c.mm$. Six difference was not found to be significant and there was a highly significant seasonal variation. 8. The differential count of male, the means of neutrophil, stab, segmented cell, Iymphocyte, monocyte, eosinophil and basophil were $31.173{\pm}0.570%$, 0.3%. $30.867{\pm}0.564%$, $55.112{\pm}0.603%$, $3.745{\pm}0.082%$, $9.867{\pm}0.422%$ and 0.14% rspectively. Female showed means of $31.010{\pm}0.572%$, 0.2%, $30.806{\pm}0.569%$, $53.929{\pm}0.634%$, $4.082{\pm}0.109%$, $10.908{\pm}0.503%$ and 0.12% respectively. There were significant sex differences in monocyte and highly significant sex difference in eosinophil, and seasonal variation were found to be highly significant in neutrophil, monocyte and eosinophil. 9. Hematological comparison made between cattles infested with so called "small type piroplasma" and non-infested group. The result of investigation showed no significant difference upon the red blood cell, hemoglobin and hematocrit values between lighty infested group and non-infested group. 10. Age distribution of test group in this study ranged from 2 years to 6 years in both sex and their average age were $4.45{\pm}0.114$(male) and $4.50{\pm}0.116$(female). There found to be no significant sex difference and seasonal variations in the age of test group.

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Estimation of Radial Spectrum for Orographic Storm (산지성호우의 환상스팩트럼 추정)

  • Lee, Jae Hyoung;Sonu, Jung Ho;Kim, Min Hwan;Shim, Myung Pil
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.10 no.4
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    • pp.53-66
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    • 1990
  • Rainfall is a phenomenon that shows a high variability both in space and time, Hy drologists are usually interested in the description of spatial distribution of rainfall over watershed. The theory of Kriging, generalized covariance technique using nonstationary mean in the regions under orographic effect, was chosen to construct random surface of total storm depth. For the constructed random surface, the double Fourier analysis of the total storm depths was performed, and the principal harmonics of storm were determined. The local component, or storm residuals was obtained by subtracting the periodic component of the storm from total storm depths. It is assumed that the residuals are a sample function of a homogeneous random field. This random field can be characterized by an isotropic one dimensional autocorrelation function or its corresponding spectral density function. Under this assumption, this study proposed a theorectical model for spectral density function adapted to two watersheds.

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Automatic assessment of post-earthquake buildings based on multi-task deep learning with auxiliary tasks

  • Zhihang Li;Huamei Zhu;Mengqi Huang;Pengxuan Ji;Hongyu Huang;Qianbing Zhang
    • Smart Structures and Systems
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    • v.31 no.4
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    • pp.383-392
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    • 2023
  • Post-earthquake building condition assessment is crucial for subsequent rescue and remediation and can be automated by emerging computer vision and deep learning technologies. This study is based on an endeavour for the 2nd International Competition of Structural Health Monitoring (IC-SHM 2021). The task package includes five image segmentation objectives - defects (crack/spall/rebar exposure), structural component, and damage state. The structural component and damage state tasks are identified as the priority that can form actionable decisions. A multi-task Convolutional Neural Network (CNN) is proposed to conduct the two major tasks simultaneously. The rest 3 sub-tasks (spall/crack/rebar exposure) were incorporated as auxiliary tasks. By synchronously learning defect information (spall/crack/rebar exposure), the multi-task CNN model outperforms the counterpart single-task models in recognizing structural components and estimating damage states. Particularly, the pixel-level damage state estimation witnesses a mIoU (mean intersection over union) improvement from 0.5855 to 0.6374. For the defect detection tasks, rebar exposure is omitted due to the extremely biased sample distribution. The segmentations of crack and spall are automated by single-task U-Net but with extra efforts to resample the provided data. The segmentation of small objects (spall and crack) benefits from the resampling method, with a substantial IoU increment of nearly 10%.

Coaxial Nozzle Electrospraying of Polymer Solutions: Use of Dispersant Flow (고분자 용액의 동축 이중노즐 전기분무: 분산제 흐름의 사용)

  • Kim, Min-Young;Lee, Jong-Hwi
    • Polymer(Korea)
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    • v.35 no.3
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    • pp.254-259
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    • 2011
  • In electrospraying of polymer solutions, metal sample collectors are often ineffective in fully removing solvent from sprayed particles and recovering redispersable sprayed particles. Herein, a novel electro spraying system, where sprayed particles were dispersed into laminar flow of dispersant (coagulation liquid), was designed for the nano-encapsulation of protein drugs. Chitosan and polyacrylic acid were used as the encapsulation materials. Aggregation of particles could be prevented by using this new electrospraying system, and unimodal size distribution was observed at an applied voltage between 4~16 kV and a low flow rate. The effects of the applied voltage on mean particle size were not significant on the other hand.