• Journal of Korean Society of Water and Wastewater
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• v.30 no.1
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• pp.33-40
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• 2016

In this study, a fluorescent silica nano particle is used as the surrogate for challenging test of membrane surface integrity. The particles are functionalized by a fluorescent dying agent so that as an ultraviolet light is imposed a bright fluorescent image from the particles can be taken. If a membrane surface is damaged and has a compromised part larger than the size of surrogate the fluorescent particles would pass through and contained in the permeate. An operator can directly notice whether the membrane surface is damaged or not by detecting a fluorescent image taken from the permeate. Additionally, the size of compromised part is estimated through analysing the fluorescent image in which we surmise the mass of particles included in the permeate by calculating an average RGB value of the image. The pilot scale experiments showed that this method could be applied successfully to determine if a membrane surface had a damaged parts regardless of the test condition. In the testing on the actual damaged area of $4.712mm^2$, the lowest error of estimating the damaged area was -1.32% with the surrogate concentration of 80 mg/L, flux of $40L/m^2/hr$ for 25 minutes of detection. A further study is still going on to increase the lowest detection limit and thus decrease the error of estimation.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.2
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• pp.171-179
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• 2014

In this study, a novel method was proposed to test the integrity of water treatment system specifically equipped with membrane filtration process. We applied the silica particles coated with a fluorescent agent (rhodamine B isothiocyanate) as a surrogate to detect a membrane process integrity and evaluate the reliability of effluent quality in the system. Additionally, a series of experiments was conducted to evaluate the sensitivity of the method through the laboratory scale experiment. The laboratory scale experiments showed that the feasibility of application of proposed method to detect a breach or damaged part on the membrane surface. However, the sensitivity on predicting the area of a breach was significantly influenced by the testing conditions such as a concentration of surrogate, filtration flux, and detection time. The lowest error of predicting the area of breach was 3.5% at the testing condition of surrogate concentration of 80 mg/L injected with flux of $20L/m^2/hr$ for 10 minutes of detection time for the breach having the actual area of $7.069mm^2$. However, the error of estimation was increased at the small breach with area less than $0.785mm^2$. A future study will be conducted to estimate a damaged area with more accuracy and precision.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.158-160
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• 1998

This paper proposed the 2-D Finite Element analysis method taking into end-ring of squirrel cage induction motor. Secondary conductor resistance can be simply replaced new one considering end-ring resistance. In the case of 2-D FEM, the end-ring resistance is hard to condsider. And the results without considering end-ring resistance have an error. To verify the proposed method we compared the analysis results and test ones.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.4
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• pp.703-713
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• 2002

Recently, an improved EFG(Element-Free Galerkin) crack analysis technique, which includes a discontinuous approximation and a singular basis function on the auxiliary supports, was developed. The technique is able to accurately analyze the crack propagation problem without any modification of the analysis model; however, it shows some dependency on the analysis parameters used. In this study, the effect of analysis parameters such as the size of compact support, dilation parameter, the smoothness of shape function around the crack tip, and the number of node using auxiliary supports on the accuracy of solution has been investigated. Through a patch test with a crack, relative L₂ error norm of stresses and the stress intensity factor were computed and compared for various analysis parameters and the results were presented as guidelines for adequate choice of analysis parameters.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.184-188
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• 2006

The purpose of the recovery experiment in clinical chemistry is performed to estimate proportional systematic error. We must know all measurements have some error margin in measuring analytical performance. Proportional systematic error is the type of error whose magnitude increases as the concentration of analyte increases. This error is often caused by a substance in the sample matrix that reacts with the sought for analyte and therefore competes with the analytical reagent. Recovery experiments, therefore, are used rather selectively and do not have a high priority when another analytical method is available for comparison purposes. They may still be useful to help understand the nature of any bias revealed in the comparison of kit experiments. Recovery should be expressed as a percentage because the experimental objective is to estimate proportional systematic error, which is a percentage type of error. Good recovery is 100.0%. The difference between 100 and the observed recovery(in percent) is the proportional systematic error. We calculated the amount of analyte added by multiplying the concentration of the analyte added solution by the dilution factor(mL standard)/(mL standard + mL specimen) and took the difference between the sample with addition and the sample with dilution. When making judgments on method performance, the observed that the errors should be compared to the defined allowable error. The average recovery needs to be converted to proportional error(100%/Recovery) and then compared to an analytical quality requirement expressed in percent. The results of recovery experiments were total protein(101.4%), albumin(97.4%), total bilirubin(104%), alkaline phosphatase(89.1%), aspartate aminotransferase(102.8), alanine aminotransferase(103.2), gamma glutamyl transpeptidase(97.6%), creatine kinase(105.4%), lactate dehydrogenase(95.9%), creatinine(103.1%), blood urea nitrogen(102.9%), uric acid(106.4%), total cholesterol(108.5), triglycerides(89.6%), glucose(93%), amylase(109.8), calcium(102.8), inorganic phosphorus(106.3%). We then compared the observed error to the amount of error allowable for the test. There were no items beyond the CLIA criterion for acceptable performance.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.2
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• pp.65-70
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• 2005

Those specifications of the CLIA analytical tolerance limits are consistent with the performance goals in Six Sigma Quality Management. Six sigma analysis determines performance quality from bias and precision statistics. It also shows if the method meets the criteria for the six sigma performance. Performance standards calculates allowable total error from several different criteria. Six sigma means six standard deviations from the target value or mean value and about 3.4 failures per million opportunities for failure. Sigma Quality Level is an indicator of process centering and process variation total error allowable. Tolerance specification is replaced by a Total Error specification, which is a common form of a quality specification for a laboratory test. The CLIA criteria for acceptable performance in proficiency testing events are given in the form of an allowable total error, TEa. Thus there is a published list of TEa specifications for regulated analytes. In terms of TEa, Six Sigma Quality Management sets a precision goal of TEa/6 and an accuracy goal of 1.5 (TEa/6). This concept is based on the proficiency testing specification of target value +/-3s, TEa from reference intervals, biological variation, and peer group median mean surveys. We have found rules to calculate as a fraction of a reference interval and peer group median mean surveys. We studied to develop total error allowable from peer group survey results and CLIA 88 rules in US on 19 items TP, ALB, T.B, ALP, AST, ALT, CL, LD, K, Na, CRE, BUN, T.C, GLU, GGT, CA, phosphorus, UA, TG tests in chematology were follows. Sigma level versus TEa from peer group median mean CV of each item by group mean were assessed by process performance, fitting within six sigma tolerance limits were TP ($6.1{\delta}$/9.3%), ALB ($6.9{\delta}$/11.3%), T.B ($3.4{\delta}$/25.6%), ALP ($6.8{\delta}$/31.5%), AST ($4.5{\delta}$/16.8%), ALT ($1.6{\delta}$/19.3%), CL ($4.6{\delta}$/8.4%), LD ($11.5{\delta}$/20.07%), K ($2.5{\delta}$/0.39mmol/L), Na ($3.6{\delta}$/6.87mmol/L), CRE ($9.9{\delta}$/21.8%), BUN ($4.3{\delta}$/13.3%), UA ($5.9{\delta}$/11.5%), T.C ($2.2{\delta}$/10.7%), GLU ($4.8{\delta}$/10.2%), GGT ($7.5{\delta}$/27.3%), CA ($5.5{\delta}$/0.87mmol/L), IP ($8.5{\delta}$/13.17%), TG ($9.6{\delta}$/17.7%). Peer group survey median CV in Korean External Assessment greater than CLIA criteria were CL (8.45%/5%), BUN (13.3%/9%), CRE (21.8%/15%), T.B (25.6%/20%), and Na (6.87mmol/L/4mmol/L). Peer group survey median CV less than it were as TP (9.3%/10%), AST (16.8%/20%), ALT (19.3%/20%), K (0.39mmol/L/0.5mmol/L), UA (11.5%/17%), Ca (0.87mg/dL1mg/L), TG (17.7%/25%). TEa in 17 items were same one in 14 items with 82.35%. We found out the truth on increasing sigma level due to increased total error allowable, and were sure that the goal of setting total error allowable would affect the evaluation of sigma metrics in the process, if sustaining the same process.

• Korean Journal of Oriental Medicine
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• v.14 no.2
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• pp.87-91
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• 2008

Background and Purpose: The purpose of this study was investigate statistical validities of previously reported articles that used various statistical techniques such as t-test and analysis of variance. Methods: To analyze the statistical procedures, 66 original articles using those statistical methods were selected from "Korean Journal of Oriental Medicine(KJOM)" published from 1995 to 2007. Results: Twenty-one articles(32%) did not report correct p-values, 33 articles(50%) used mean${\pm}$standard error(mean${\pm}$SE) and 11 articles(l7%) used mean${\pm}$standard deviation(mean${\pm}$SD). Fifty-two articles(95%) of 55 ones which were tested for normal distribution made an error in describing normal distribution. Seventeen articles misused t-test and 12 articles did not carry out the multiple comparison. Conclusions: The training of researchers with clinical statistics or the participation of statisticians in research design will reduce the significant errors in statistical interpretation of the results.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.33-44
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• 2003

This study was conducted to estimate the design flood by the determination of best fitting order for LH-moments of the annual maximum series at fifteen watersheds. Using the LH-moment ratios and Kolmogorov-Smirnov test, the optimal regional probability distribution was identified to be the Generalized Extreme Value (GEV) in the first report of this project. Parameters of GEV distribution and flood flows of return period n years were derived by the methods of L, L1, L2, L3 and L4-moments. Frequency analysis of flood flow data generated by Monte Carlo simulation was performed by the methods of L, L1, L2, L3 and L4-moments using GEV distribution. Relative Root Mean Square Error. (RRMSE), Relative Bias (RBIAS) and Relative Efficiency (RE.) using methods of L, Ll , L2, L3 and L4-moments for GEV distribution were computed and compared with those resulting from Monte Carlo simulation. At almost all of the watersheds, the more the order of LH-moments and the return periods increased, the more RE became, while the less RRMSE and RBIAS became. The Absolute Relative Reduction (ARR) for the design flood was computed. The more the order of LH-moments increased, the less ARR of all applied watershed became It was confirmed that confidence efficiency of estimated design flood was increased as the order of LH-moments increased. Consequently, design floods for the appled watersheds were derived by the methods of L3 and L4-moments among LH-moments in view of high confidence efficiency.

• English Language & Literature Teaching
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• v.12 no.3
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• pp.1-24
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• 2006

This study investigated differences in beliefs about English learning of 286 EFL college students and 52 English teachers in Korea. Data was collected using Horwitz's Beliefs About Language Learning Inventory and compared between students and teachers in beliefs. To address the research questions, the data were analyzed through descriptive statistics including frequencies, factor analysis, MANOVA, ANOVA, t-test, and reliability coefficients. The results showed four factors in student beliefs: Difficulty of learning English, nature of learning English, importance of correctness in learning English, and motivation and perceived importance of learning English. Clear differences were found in students and teachers' beliefs in English learning aptitude and importance of translation, error correction, and grammar rules. A few belief differences were also identified between Koreans and native-speaking English teachers related to the importance of vocabulary learning, pronunciation, and cultural knowledge. The findings of the study indicated that background variables such as gender and major field of study have an effect on student beliefs about L2 learning. The present study also provided pedagogical considerations to reduce mismatch between students and teachers beliefs and to improve the L2 planning and instruction.

• KSBB Journal
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• v.17 no.4
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• pp.403-408
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• 2002

For stimulating the in vivo secretion of IGF-1 (insulin-like growth factor-1) which is well known to promote the various physiological actions in human body, the natural herbal extract, YGF251 (young growth factor 251), was developed and evaluated for its effect as IGF-1 secretagogue in this study. The clinical study was peformed as double blind test, and 31 adult female and male volunteers between the age of 40 and 70 were investigated for their changes of concentration of IGF-1 , insulin level, weight, blood pressure, and liver and kidney functions. As the result of paired sample test on the change of the concentration of IGF-1, in YGF251 treated group, it was 245.6 ng/mL before dosing. The concentration of IGF-1 was increased to 269.3 ng/mL after a month and to 275.6 ng/mL after two months, and both were statistically significant (p〈0.05). While in control group, the concentration of IGF-1 was 280.0 ng/mL before dosing, but decreased to 239.2 ng/mL after a month and to 230.2 ng/mL after two months, and both were also statistically significant (p〈0.05). In YGF251 treated group, the concentration of insulin in blood increased about 2 times after a month dosing as an average level, but in control group, it showed a decrease of 36% compared with before dosing. And there were little changes regarding to the measured weight and blood pressure. Various measured data in order to observe the alteration in liver and kidney functions by the administration of YGF251 showed a little change within measuring error range.