• Journal of the Korean Geotechnical Society
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• v.24 no.8
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• pp.111-123
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• 2008

Geotechnical engineering problems are characterized by many sources of uncertainty. Some of these sources are connected to the uncertainties of soil properties involved in the analysis. In this paper, a numerical procedure for a probabilistic analysis that considers the spatial variability of soil properties is presented to study the response of spatially random soil. The approach integrates a commercial finite difference method and random field theory into the framework of a probabilistic analysis. Two-dimensional non-Gaussian random fields are generated based on a Karhunen-$Lo{\grave{e}}ve$ expansion in a fashion consistent with a specified marginal distribution function and an autocorrelation function. A Monte Carlo simulation is then used to determine the statistical response based on the random fields. A series of analyses were performed to study the effects of uncertainty due to the spatial heterogeneity on the settlement and bearing capacity of a rough strip footing. The simulations provide insight into the application of uncertainty treatment to the geotechnical problem and show the importance of the spatial variability of soil properties with regard to the outcome of a probabilistic assessment.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.2
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• pp.63-74
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• 2015

This study investigated the influence of probabilistic variability in stiffness and nonlinearity of soil on response of nuclear power plant (NPP) structure subjected to seismic loads considering the soil-structure interaction (SSI). Both deterministic and probabilistic methods have been employed to evaluate the dynamic responses of the structure. For the deterministic method, $SRP_{min}$ method given in USNRC SRP 3.7.2(2013) (envelope of responses using three shear modulus profiles of lower bound($G_{LB}$), best estimate($G_{BE}$) and upper bound($G_{UB}$)) and $SRP_{max}$ method (envelope of responses by more than three ground profiles within range of $G_{LB}{\leq}G{\leq}G_{UB}$) have been considered. The probabilistic method uses the Latin Hypercube Sampling (LHS) that can capture probabilistic feature of soil stiffness defined by the median and the standard deviation. These analysis results indicated that 1) number of samples shall be larger than 60 to apply the probabilistic approach in SSI analysis and 2) in-structure response spectra using equivalent linear soil profiles considering the nonlinear behavior of soil medium can be larger than those based on low-strain soil profiles.

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.1
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• pp.216-230
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• 2008

Purpose: The purpose of this study is to analysis on the Stress Response Inventory(SRI) and Heart Rate Variability (HRV) of some dysmenorrhoea patients. Methods: We studied 34 patients visiting OO Medical Center from May 2007 to November 2007. And the severity of dysmenorrhoea were measured by Multidimensional Verbal Rating scale(MVRS), Verbal Rating scale (VRS) and Visual Analog Scale(VAS). And SRI and HRV were recorded. Results: According to comparison of Means of HRV values among the groups, most of them were not statistically significant. But the comparison of Means of SRI, the points of almost all values were kept by order of Severe-Moderate-Mild-None group. Most of them are statistically significant. According to correlation analysis between dysmenorrhoea scale and HRV, most of them were not statistically significant. But the correlation analysis between HRV and SRI, there were some correlations. And the correlation analysis between SRI and dysmenorrhoea scale, most of them were statistically significant. According to General Linear Model of Dysmenorrhoea $scale^{\ast}SRI$ and HRV. Dysmenorrhoea scale and SRI influenced values of HRV. But it is hard to conclude the relationship between Dysmenorrhoea $scale^{\ast}SRI$ and HRV Conclusion: The results suggest that stress is related to dysmenorrhoea. But the relation between dysmenorrhoea and HRV was hard to conclude. We need more study for settling the relation between dysmenorrhoea and HRV.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.19 no.2
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• pp.75-90
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• 2015

Objectives The purposes of this study was to develope a Qi gong exercise that suits characteristics of post mastectomy women, and to evaluate the effect of Qi gong exercise on immune response, blood circulation index, pulse wave parameter and heart rate variability. Methods This study was applied to total 35 post mastectomy women, including 17 for experiment group and 18 for control group. The Qi gong exercise was composed of total 24 times of 90 minutes per each time, twice a week, and 12 weeks and it was conducted by the oriental medicine professor who was an expert of Qi gong exercise. Results 1. Two group comparison revealed that the experimental group had significantly improved immune response(p<.021), HR(beats/min)(p<.001), ESV(ml/beat)(p=.038), ESI($ml/beat/m^2$)(p=.040), ECO (L/min)(p=.019), ECI($L/min/m^2$)(p=.023), ECRI($dyne^*sec/cm$)(p=.015), Left Kwan($div^3$)(p=.021), Right Kwan($div^3$)(p=.038), Mean HRV(cycle/min)(p<.001), SDNN(ms)(p=.043), RMSSD(ms)(p=.040), and TP(log $ms^2$)(p=.039). 2. Two group comparison revealed that the experimental group had significantly decreased ECR ($dyne^*sec^*cm^{-5}$) (p=.034), Left RAI(p=.044), Right RAI(p=.042), and pNN50(%)(p=.038). Conclusions These results from Qi gong exercise program can be used as basic data for development of health promotion program for Post Mastectomy Women.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1071-1078
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• 2006

Robust design of products or processes is a way to produce products or processes with less variability on condition that the product specification is met, so that the ratio of nonconforming products can be as minimized as possible. In such models as robust parameter design(RPD) originated by Taguchi and response surface methodology(RSM), the variances of noise variables are assumed to be measurable. However, there are circumstances in which the experimenters are unable to measure noise variables or perhaps are not aware of what the noise variables are. In this paper, it is demonstrated through an example that Taguchi's RPD approach can be conducted within the framework of the analysis of variability, with a view to a comparison of the two methods.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.185-186
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• 1998

The discrete Wigner-distribution(DWD) was implemented for the time-frequency analysis of heart rate variability signals. The smoothed cross-DWD was used to estimate time-varying power spectrum. Spurious cross-terms were suppressed using a smoothing data window and a Gauss frequency window. The DWD is very easy to implement using the FFT algorithm. Experiment show that the DWD follows well the instantaneous changes of spectral content of heart rate variability signals, which characterize the dynamics of autonomic nervous system response.

• Mycobiology
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• v.43 no.4
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• pp.444-449
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• 2015

Arbuscular mycorrhizal fungi (AMF) are ubiquitous in the rhizosphere and form symbiotic relationships with most terrestrial plant roots. In this study, four strains of Rhizophagus clarus were cultured and variations in their growth characteristics owing to functional diversity and resultant effects on host plant were investigated. Growth characteristics of the studied R. clarus strains varied significantly, suggesting that AMF retain high genetic variability at the intraspecies level despite asexual lineage. Furthermore, host plant growth response to the R. clarus strains showed that genetic variability in AMF could cause significant differences in the growth of the host plant, which prefers particular genetic types of fungal strains. These results suggest that the intraspecific genetic diversity of AMF could be result of similar selective pressure and may be expressed at a functional level.

• The Korean Journal of Applied Statistics
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• v.15 no.1
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• pp.45-55
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• 2002

The 2-level rotation design based on 3 rotation groups is discussed in view of Monthly Retail Trade Survey conducted by the Bureau of Census in U.S., and composite estimators for population characteristics are concerned. The generalized composite estimators and the recursive composite estimators are presented at 2-level rotation design with design gap and variance formulas for the composite estimators are provided. Also under the response variability related with covariance structure and correlation structure from repeated response, relative efficiencies of the composite estimators are compared.

• Structural Engineering and Mechanics
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• v.39 no.6
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• pp.877-893
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• 2011

Response spectra of earthquake ground motions are important in the earthquake-resistant design and reliability analysis of structures. The formulation of the response spectrum in the frequency domain efficiently computes and evaluates the stochastic response spectrum. The frequency information of the excitation can be described using different functional forms. The shapes of the calculated response spectra of the excitation show strong magnitude and site dependency, but weak distance dependency. In this paper, to compare the effect of the earthquake ground motion variables, the contribution of these sources of variability to the response spectrum's uncertainty is calculated by using a stochastic analysis. The analytical results show that earthquake source factors and soil condition variables are the main sources of uncertainty in the response spectra, while path variables, such as distance, anelastic attenuation and upper crust attenuation, have relatively little effect. The presented formulation of dynamic structural response in frequency domain based only on the frequency information of the excitation can provide an important basis for the structural analysis in some location that lacks strong motion records.

• Structural Engineering and Mechanics
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• v.22 no.6
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• pp.647-664
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• 2006

The main purpose of this paper is to investigate the effect of transient stochastic analysis on nonlinear response of earth and rock-fill dams to spatially varying ground motion. The dam models are analyzed by a stochastic finite element method based on the equivalent linear method which considers the nonlinear variation of soil shear moduli and damping ratio as a function of shear strain. The spatial variability of ground motion is taken into account with the incoherence, wave-passage and site response effects. Stationary as well as transient stochastic response analyses are performed for the considered dam types. A time dependent frequency response function is used throughout the study for transient stochastic responses. It is observed that stationarity is a reasonable assumption for earth and rock-fill dams to typical durations of strong shaking.