• Biomedical Science Letters
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• v.18 no.3
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• pp.268-275
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• 2012

Reference ranges of standard experimental parameters are useful for comparisons in toxicology. The aim of this study was to collect data from 4-week repeated toxicity studies in Crl:CD (SD) rats, a strain widely used for toxicity and efficacy research, for establishing domestic reference values. Data on body weight, food consumption; urinalysis, hematological, and blood biochemical parameters; and organ weights were collected from 16 toxicity studies in 220 Crl:CD (SD) rats (110 males and 110 females). The studies had been performed at a single testing facility over the last 3 years and involved animals sourced from a single breeder. The findings were collated as means, standard deviations, percentages, and ranges. Urine volume, uterus weight, eosinophil, and basophil counts, and triglyceride, total bilirubin, and gammaglutamyl transpeptidase levels showed standard deviations of 30% or more. These historical control data would help to interpret the effects of test substances in routine toxicity and efficacy studies.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.1
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• pp.19-25
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• 2000

In Condebelt press drying system, the temperature difference between top and bottom plate of Condebelt transfers water to bottom side, Fine fibers, stickies , ink , and various inorganic materials are also migrated to the fine wire located at the bottom plate by highly pressurized moisture flow. As a result, the fine wire contaminated by plugging of these fine and sticky materials can cause many problems such as blistering or partial crushing of paper. The contaimination of fine wire leads to a deterioroated strength together with uneven physical properties of paper. In this paper, froth-flotatiion method, which is commonly used in the field of ONP recycling process, were adopted to separate the contaminants in KOCC as a new fiber fractionation method. Standard deviation of paper strength and brighteness decreased of Condebelt fine wire were measured to investigate the effect of contaminants removal . The standard deviations of paper strength obtained from the flotated accept were not dependent on the number of condebelt press drying . However, in the case of untreated KOCC, the standard deviations were increased as press drying repeated. This indicates that the contaminant gives uneven physical properties to the paper by wire plugging . Optical and SEM images clearly illustrate the effect of contaminants on the wire condition.

• Journal of Climate Change Research
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• v.9 no.1
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• pp.103-115
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• 2018

The uncertainty of climate scenarios, as initial information, is one of the significant factors among uncertainties of climate change impacts and vulnerability assessments. In this sense, the quantification of the uncertainty of climate scenarios is essential to understanding these assessments of impacts and vulnerability for adaptation to climate change. Here we quantified the precision of surface temperature of ensemble scenarios (high resolution (1km) RCP4.5 and 8.5) provided by Korea Meteorological Administration, with spatiotemporal variation of the standard deviation of them. From 2021 to 2050, the annual increase rate of RCP8.5 was higher than that of RCP4.5 while the annual variation of RCP8.5 was lower than that of RCP4.5. The standard deviations of ensemble scenarios are higher in summer and winter, particularly in July and January, when the extreme weather events could occur. In general, the uncertainty of ensemble scenarios in summer were lower than those in winter. In spatial distribution, the standard deviation of ensemble scenarios in Seoul Metropolitan Area is relatively higher than other provinces, while that of Yeongnam area is lower than other provinces. In winter, the standard deviations of ensemble scenarios of RCP4.5 and 8.5 in January are higher than those of December. Especially, the standard deviation of ensemble scenarios is higher in the central regions including Gyeonggi, and Gangwon, where the mean surface temperature is lower than southern regions along with Chungbuk. Such differences in precisions of climate ensemble scenarios imply that those uncertainty information should be taken into account for the implementation of national climate change policy.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.4
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• pp.35-52
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• 2013

Markowitz's portfolio selection model is used to construct an optimal portfolio which has minimum variance, while satisfying a minimum required expected return. The model uses estimators based on analysis of historical data to estimate the returns, standard deviations, and correlation coefficients of individual stocks being considered for investment. However, due to the inaccuracies involved in estimations, the true optimality of a portfolio constructed using the model is questionable. To investigate the effect of estimation inaccuracy on actual portfolio performance, we study the changes in a portfolio's realized return and standard deviation as the accuracy of the estimations for each stock's return, standard deviation, and correlation coefficient is increased. Furthermore, we empirically analyze the portfolio's performance by comparing it with the performance of active mutual funds that are being traded in the Korean stock market and the KOSPI benchmark index, in terms of portfolio returns, standard deviations of returns, and Sharpe ratios. Our results suggest that, among the three input parameters, the accuracy of the estimated returns of individual stocks has the largest effect on performance, while the accuracy of the estimates of the standard deviation of each stock's returns and the correlation coefficient between different stocks have smaller effects. In addition, it is shown that even a small increase in the accuracy of the estimated return of individual stocks improves the portfolio's performance substantially, suggesting that Markowitz's model can be more effectively applied in real-life investments with just an incremental effort to increase estimation accuracy.

• Korean Journal of Crystallography
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• v.8 no.1
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• pp.64-65
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• 1997

A method for calculation of the estimated standard deviation (ESD) of physical quantities which are functions of experimentally observed variables has been shown.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1106-1108
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• 1993

This paper deals with an industrial application of a fuzzy feedback combined learning control to an industrial batch free radical polymerization reactor. As a result, the plant has reduced the batch reaction time by 50 minute and stabilized both by 40 percent reduction of the standard deviations of product qualities, such as the total solid content and the graft gum, and by 45 percent reduction of the standard deviation of the batch reaction end time.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.287-292
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• 2001

Prupose : We analyzed setup errors induced by using air-vacuum cushion as immobilization device in patients with rectal cancer. Materials and methods : We had treated the twenty patients with rectal cancer by 6 MV, 10 MV X-ray from Aug. 1998 to Aug. 1999 at Chungnam National University Hospital. All patients were treated at prone position. They were separated to two groups, control group, 10 patients using styrofoam, and test group, 10 patients using styrofoam and air-vacuum cushion. We measured errors of posterior field for x, y axis and lateral field for z, y axis with simulation film and EPID image using a matching technique. Results : In control group, the mean displacement values of pelvic bone landmark for x axis and y axis were 0.02 mm. 0.78 mm, respectively and the standard deviations of systematic error were 2.13 mm, 2.40 mm, respectively and the standard deviation of random error were 1.46 mm. 1.51 mm, respectively. In test group, the mean displacement values of x axis and y axis were -0.33 mm. 0.81 mm, respectively and the standard deviations of systematic error were 1.71 mm, 3.08 mm, respectively and the standard deviations of random errors were 1.40 mm. 1.88 mm, respectively. The mean displacement values of z axis and y axis were 2.98 mm. 0.74 mm, respectively and the standard deviations of systematic error were 4.75 mm, 2.65 mm, respectively and standard deviations of random error were 2.69 mm. 1.86 mm, respectively. The statistical difference of field size by using air vacuum cushion between two groups in posterior direction and lateral direction was not shown. Conclusion : We think that use of air-vacuum cushion may not be an advantage for improving setup accuracy in rectal cancer patients.

• Journal of the Korean Chemical Society
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• v.56 no.4
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• pp.424-430
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• 2012

Densities, viscosities, refractive indices and speed of sounds of the binary mixtures of Acetophenone with Ethylchloroacetate were measured over the entire mole fractions at (303.15, 313.15 and 323.15) K. From these experimental results, excess molar volume $V^E$, viscosity deviation ${\Delta}{\eta}$, refractive index deviation ${\Delta}n_D$, deviations in speed of sound ${\Delta}u$, deviations in isentropic compressibility ${\Delta}k_s$ and excess intermolecular free length ${\Delta}L_f$ were calculated. The viscosity data have been correlated with the equations of Grunberg and Nissan, Hind et al., Tamura and Kurata, Katti and Chaudri, Sedgwick, Krishnan-Laddha and McAllister. The thermo physical properties under study were fit to the Jouyban-Acree model. The excess values were correlated using Redlich-Kister polynomial equation to obtain their coefficients and standard deviations. It was found that in all cases, the data obtained fitted with the values correlated by the corresponding models very well. The results are interpreted in terms of molecular interactions occurring in the solution.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.3
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• pp.190-196
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• 2009

A new time adapted threshold using the standard deviations of Wavelet coefficients after Wavelet transform by frame scale is proposed. The time adapted threshold is set up using the sum of standard deviations of Wavelet coefficient in level 3 approximation and weighted level 1 detail. Level 3 approximation coefficients represent the voiced sound with low frequency and level 1 detail coefficients represent the unvoiced sound with high frequency. After reducing noise by soft thresholding with the proposed time adapted threshold, there are still residual noises in silent interval. To reduce residual noises in silent interval, a detection algorithm of silent interval is proposed. From simulation results, it can be noticed that SNR and MSE of the proposed algorithm are improved than those of Wavelet transform and than those of Wavelet packet transform.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.2
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• pp.180-183
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• 1990

The variability of ambient noise with time and water depth is measured in the coastal water of Pusan. The Noise Spectrum levels are relatively high, and have standard deviations amounting to 3 to 4 dB with time and 2 to 3 dB with water depth in the B area of high ship activity. On the other hand, in the A area where shipping is sparse the standard deviations are only 1 to 2 dB with time and water depth respectively. These results show that ship traffic is one of the dominent sources at frequencies greater than 500Hz.