• Journal of Environmental Science International
• /
• v.18 no.6
• /
• pp.595-601
• /
• 2009

The effects of the cation-to-anion resin ratio and bed depth on ion exchange performance of mixed-bed were studied at ultralow solution concentration. Breakthrough curves were experimentally obtained for NaCI solution as functions of resin ratio and bed depth. The bed depth affects the pattern of the sodium breakthrough curve but not the chloride breakthrough curve in beds because of the selectivity difference. Resin selectivity determines the shape of breakthrough curves, Some sodium and chloride breakthrough curves crossed at a point as a function of resin ratio. The lower cation-to-anion resin ratio showed the higher effluent concentration or treated volume of the crossover point regardless of the total resin weight.

• ETRI Journal
• /
• v.32 no.5
• /
• pp.687-694
• /
• 2010

Breaks in presence (BIP) are those moments during virtual environment (VE) exposure in which participants become aware of their real world setting and their sense of presence in the VE becomes disrupted. In this study, we investigate participants' experience when they encounter technical anomalies during game play. We induced four technical anomalies and compared the BIP responses of a navigation mode game to that of a combat mode game. In our analysis, we applied a linear mixed model (LMM) and compared the results with those of a conventional regression model. Results indicate that participants felt varied levels of impact and recovery when experiencing the various technical anomalies. The impact of BIPs was clearly affected by the game mode, whereas recovery appears to be independent of game mode. The results obtained using the LMM did not differ significantly from those obtained using the general regression model; however, it was shown that treatment effects could be improved by consideration of random effects in the regression model.

• Tribology and Lubricants
• /
• v.16 no.2
• /
• pp.106-113
• /
• 2000

Effects of surface roughness on bearing performances are investigated numerically in this study, especially for the parallel thrust bearing. Although mating surfaces are parallel and separated by thin fluid film, the pressure distribution is formed due to asperities. Model surface is generated numerically with given autocorrelation function and some surface profile parameters. Then the average Reynolds equation is applied to predict the effects of surface roughness between hydrodynamic and mixed lubrication regimes. In this equation, flow factors are defined as correction terms to smooth out high frequency surface roughness. The correlation length is proposed to get the minimum load for the parallel thrust bearing for various sliding conditions.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2003.11a
• /
• pp.201-209
• /
• 2003

In the mixed lubrication regime, the roughness effects are very important due to the presence of interacting asperities. An average Reynolds equation using flow factors is very useful to determine effects of surface roughness on mixed lubrication. In this paper, the pressure flow factors and shear stress factor for Gaussian and non-Gaussian surfaces are evaluated in terms of kurtosis and skewness. particularly, the elastic deformation of the surface is considered.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1995.05a
• /
• pp.158-162
• /
• 1995

Synergistic effects of mixed solvents, especially with mixtures of CS$_2$ with electron donor solvents, in inducing desired structural changes in coals were studied by solvent swelling techniques in addition to differential scanning calorimetric analyses. Mixed solvents exhibit significant synergistic efficacy in swelling the coal structure of medium bituminous rank. This synergy effect appears to be physical origin that is closely related to matching solubility parameters. Since the swollen coal structure can be obtained by mixed solvents with CS$_2$ at room temperature instead of high temperature, many possible technological pathways for economical utilization of coal might be sought.

• Korean Journal of Food Science and Technology
• /
• v.43 no.4
• /
• pp.518-523
• /
• 2011

The aim of this study was to evaluate the antimicrobial activities of leek and garlic extract juice and powder against Escherichia coli, Salmonella enteritidis, and Staphylococcus aureus in a single strain and a mixed strains system. Garlic juice and powder showed higher antimicrobial activity against Sta. aureus than that of E. coli or S. enteritidis. The antimicrobial activities of the leek and garlic powders decreased with increasing temperature and time, but stabilized at various pHs. The antimicrobial effects of mixtures of various ratios between the leek and garlic extracts increased with an increase in garlic extract content. No synergistic effects by the leek and garlic mixtures were observed. In a mixed strains system, the antimicrobial effects of leek and garlic powder were similar to those in a single strain system.

• The Korean Journal of Applied Statistics
• /
• v.28 no.2
• /
• pp.289-294
• /
• 2015

Linear mixed models are commonly used in the clinical pharmaceutical studies to analyze repeated measures such as the crossover study data of bioequivalence studies. In these models, random effects describe the correlation between repeated outcomes and variance-covariance matrix explain within-subject variabilities. Bioequivalence analysis verifies whether a 90% confidence interval for geometric mean ratio of Cmax and AUC between reference drug and test drug is included in the bioequivalence margin [0.8, 1.25] performed using linear mixed models with period, sequence and treatment effects as fixed and sequence nested subject effects as random. A Levofloxacin study is referred to for an example of real data analysis.

• Journal of Contemporary Eastern Asia
• /
• v.12 no.1
• /
• pp.21-34
• /
• 2013

How do mixed legislative systems shape voter behavior and public perceptions? Through an analysis of the electoral systems in Japan, South Korea, and Taiwan, this paper evaluates the extent to which the public in these three countries understand their mixed systems and whether claims of voter ignorance translate into irrational voting behavior based on the institutional effects of mixed systems. Through a multi-method approach including data from outside of East Asia, this analysis seeks to determine whether these three cases exhibit patterns consistent with other mixed systems. Empirical analysis affirms levels of strategic voting consistent with comprehension of electoral rules. Furthermore, this analysis suggests a disconnect between practical knowledge and electoral expectations.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1508-1512
• /
• 2003

In this study, retardation behavior of fatigue crack under single overloading of the mixed mode state was experimentally investigated. To produce single overload in the mixed mode I+II state, the compact tension shear (CTS) specimen and loading device were used. The propagation tests for fatigue crack were performed under mode I and mixed-mode loading overloading afterwards. We examined the observed deformation aspects, the variation of fatigue life and crack propagation rate, and the aspects of retardation behavior from tests. The retardation effect of mixed-mode single overload on fatigue crack propagation behavior was smaller than that of mode I single overload. Also the loading modes of variable and constant amplitude loads have influence on the retardation behavior of fatigue cracks.

• Phonetics and Speech Sciences
• /
• v.7 no.4
• /
• pp.131-138
• /
• 2015

The initial syllables of a pair of Sino-Korean words are generally differentiated in their meaning by either short or long durations. They are realized differently by the dialect and generation of speakers. Recent research has reported that the temporal distinction has gradually faded away. The aim of this study is to examine whether college students with Kyungsang dialect made the distinction temporally using a statistical method of Mixed Effects Model. Thirty students participated in the recording of five pairs of Korean words in clear or casual speaking styles. Then, the author measured the durations of the initial syllables of the words and made a descriptive analysis of the data followed by applying Mixed Effects Models to the data by setting gender, length, and style as fixed effects, and subject and syllable as random effects, and tested their effects on the initial syllable durations. Results showed that college students with Kyungsang dialect did not produce the long and short syllables distinctively with any statistically significant difference between them. Secondly, there was a significant difference in the duration of the initial syllables between male and female students. Thirdly, there was also a significant difference in the duration of the initial syllables produced in the clear or casual styles. The author concluded that college students with Kyungsang dialect do not produce long and short Sino-Korean syllables distinctively, and any statistical analysis on the temporal aspect should be carefully made considering both fixed and random effects. Further studies would be desirable to examine production and perception of the initial syllables by speakers with various dialect, generation, and age groups.