• Communications for Statistical Applications and Methods
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• v.10 no.2
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• pp.361-370
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• 2003

Those who are interested in making inferences concerning linear combination of valiance components in a simple linear regression model with unbalanced nested error structure can use the confidence intervals proposed in this paper. Two approximate confidence intervals for the sum of two variance components in the model are proposed. Simulation study is peformed to compare the methods. The methods are applied to a numerical example and recommendations are given for choosing a proper interval.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.3
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• pp.420-424
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• 1987

The model reduction methods of the linear time invariant continuous systems are proposed. The energy dispersion method is used to obtain the model denominator. And the model numerator is found by the modified residue method or the time moment matching method. The methods suggested are compared with the method suggested by Lucas and give good results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.404-406
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• 2014

The NDIF method is developed for eigenvalue analysis of arbitrarily shaped two-dimensional acoustic cavity with a mixed boundary, which consists of rigid-wall and open boundaries. The NDIF method, which was developed by the author in 2000, has the feature that it yields highly accurate eigenvalues compared with other analytical methods or numerical methods (FEM and BEM). The validity of the proposed method is shown in a case study, which indicate that eigenvalues obtained by the proposed method are more accurate compared to the exact method or FEM(ANSYS).

• Communications for Statistical Applications and Methods
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• v.20 no.3
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• pp.235-240
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• 2013

Generalized linear mixed models(GLMMs) are frequently used for the analysis of longitudinal categorical data when the subject-specific effects is of interest. In GLMMs, the structure of the random effects covariance matrix is important for the estimation of fixed effects and to explain subject and time variations. The estimation of the matrix is not simple because of the high dimension and the positive definiteness; subsequently, we practically use the simple structure of the covariance matrix such as AR(1). However, this strong assumption can result in biased estimates of the fixed effects. In this paper, we introduce Bayesian modeling approaches for the random effects covariance matrix using a modified Cholesky decomposition. The modified Cholesky decomposition approach has been used to explain a heterogenous random effects covariance matrix and the subsequent estimated covariance matrix will be positive definite. We analyze metabolic syndrome data from a Korean Genomic Epidemiology Study using these methods.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.3
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• pp.36-42
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• 2006

The analytical realization of uncoupled system was introduced in this study using times series and its spectrum analysis. The ARMAX spectra of time series methods were compared with the conventional FFT spectrum. Also, the response of second order system uncoupled was solved using the Runge-Kutta Gill method. In this numerical analysis, the displacement, velocity and acceleration were calculated. The displacement response among them was used for the power spectrum analysis. The ARMAX algorithm in time series was proved to be appropriate for the mode estimation and spectrum analysis. Using the separate response of first and second mode, each modes were calculated separately and the response of mixed modes was also analyzed for the mode estimation using several time series methods.

• The Journal of Korean Academic Society of Nursing Education
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• v.27 no.4
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• pp.423-435
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• 2021

Purpose: The purpose of this study is to identify the educational needs of a severe trauma treatment simulation program based on mixed reality which combines element of both virtual reality and augmented reality. Methods: Focus group interviews were conducted with ten military hospital nurses on February 4 and 5, 2021. The collected data were analyzed using a qualitative content analysis. As a framework for data analysis, the educational needs were clustered into the following four categories: teaching contents, teaching methods, teaching evaluation, and teaching environment. Results: The educational needs for each category that emerged were as follows: three subcategories including "realistic education reflecting actual clinical practice" and "motivating education" for teaching contents; five subcategories including "team-based education," "repeated education that acts as embodied learning," and "stepwise education" for teaching methods; six subcategories including "debriefing through video conferences," "team evaluation and evaluator in charge of the team," "combination of knowledge and practice evaluation" for teaching evaluation; six subcategories including "securing safety," "similar settings to real clinical environments," "securing of convenience and accessibility for learners," and "operating as continuing education" for teaching environment. Conclusion: The findings of this study can provide a guide for the development and operation of a severe trauma treatment simulation program based on mixed reality. Moreover, it suggests that research to identify the educational needs of various learners should be conducted.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.35-45
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• 2021

Digestate or slurry produced from anaerobic digestion is mostly applied to crop lands for its disposal and recovering nutrients. However, minimizing nitrogen losses following field application of the digestate is important for maximizing the plant's nitrogen uptake and reducing environmental concerns. This study was conducted to assess the effects of three different biogas digestate application techniques (sawdust mixed with digestate (SSD), the hole application method (HA), and digestate injected in the soil (SD)) on nitrate leaching potential in the soil. A pot laboratory experiment was conducted at room temperature of 25 ± 2 ℃ for 107 days. The experimental results showed that sawdust application method turned out to be appropriate for quick immobilization of surplus N in the form of microbial biomass N, reflecting its lower total nitrogen and NH₄-N contents and low pH. The NH₄-N and total nitrogen fate in the soil fertilized with manure showed no statistically significant (p > 0.05) differences between the different methods applied during the incubation time under room temperature. In contrast, NO₃-N concentration indicates significant reduction in sawdust treatment (p < 0.05) compared to the control and other application methods. However, the soil sawdust mixed with digestate was more effective than the other methods, because of the cumulative labile carbon contents of the amendment, which implies soil net N immobilization.

• Journal of Acupuncture Research
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• v.20 no.5
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• pp.227-235
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• 2003

Objective : In the pain control, BU herbal acupuncture is highly effective but causes many phys ical reactions. This study was done to compare BU with BU mixed Hwangryunhaedoktang(HHT, 黃連解毒湯) herbal acupucture in decreasing physical reactions of BU. Methods : We injected BU Group(N=12) and BU mixed HHT Group(N=12) at four points of Fenmen(B12), Feishu(B13), Fufen(B41) and Pohu(B42). Then we observe the local thermal changes and the physical reactions at beginning, 1hour and 24 hours after administering herbal acupuncture through the D.I.T.I. and survey. Results : The following results were obtained; 1. The significant dermatothermal difference had been checked 1hour and 24hours in BU group, but 1hour in Bu mixed HHT. 2. In BU group, the difference of temperature had been continued highly until 24hours. But in BU mixed group, the difference of temperature had been continued highly until 1 hour but decreased nearly equal to beginning stage until 24hours. 3. The symptoms which appear following the herbal acupuncture administration were less appeared in BU mixed HHT than BU group.

• The Journal of Korean Medicine
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• v.36 no.3
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• pp.135-143
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• 2015

Objectives: Recently lactic acid formulation was known as the adjuvant therapy on atopic dermatitis(AD) symptoms because of little side effects. In this study, it was studied that Lactobacillus mixed culture appliment was effective on not on AD symptoms. Methods: The case-photos 30-40 times of AD symptoms from case were observed with literatures. The case-photos were acquired with environmental AD dermatitis experience program which is conducted in SUNCHANG RESERCH INSTITUTE OF HEALTH AND LONGEVITY from 2014.01 to 2014.08. Experience applicants were limited the oral administration and chemical external administration. Results: Lactobacillus mixed culture appliment was effective because of the mitigation or disappearance of AD primary symptoms like pruritus, erythema, edema, effusion, dry skin, scaly, scab etc. AD symptom degree was dependent on lactobacillus mixed culture appliment times, and classified as Reaction Period (RAP), Reduction Period (RDP), Efection Period (EP), Reproduction Period (RPP) on a single mixed culture appliment time. And AD symptoms which were appeared in RPP were classified as Rebound Period (RBP), Effection Period (EP), Subclinical Period (SCP). Conclusions: Lactobacillus mixed culture appliment is considered to be useful for AD symptoms and is estimated to be effective by different mechanism with oral administration or steroid ointment application. Lactobacillus mixed culture appliment is expected to induce a synergistic effects on AD symptom reliefs with the other oral administration.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.119-124
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• 2023

In this study, experimental approach of the measurement of condensation and evaporation heat transfer coefficients is discussed for mixed refrigerants using in the ultra low-temperature cooling system for semiconductor etching process. An experimental apparatus was described performing the condensation and evaporation heat transfer measurements for mixed refrigerants. The mixed refrigerant used in this study was composed of the optimal mixture determined in previous research, with a composition of Ar:R14:R23:R218 = 0.15:0.4:0.15:0.3. The experiments were conducted over a temperature range from -82℃ to 15℃ and at pressures ranging from 18.5 bar to 5 bar. The convection heat transfer coefficients of the mixed refrigerant were measured at flow rates corresponding to actual operating conditions. The condensation heat transfer coefficient ranged from approximately 0.7 to 0.9 kW/m2K, while the evaporation heat transfer coefficient ranged from 1.0 to 1.7 kW/m2K. The detailed discussion of the experimental methods, procedures, and results were described in this paper.