• Korean Chemical Engineering Research
• /
• v.44 no.5
• /
• pp.444-452
• /
• 2006

This paper reports experimental excess molar volumes $V^E_m$ using a digital vibrating-tube densimeter and excess molar enthalpies $H^E_m$ by means of an isothermal microcalorimeter with a flow mixing cell for the binary mixtures{1,2-dichloropropane + 2-(2-methoxyethoxy)ethanol} and {1,2-dichloropropane + 2-(2-ethoxyethoxy)ethanol} at 298.15 K under atmospheric pressure. All the $V^E_m$ and $H^E_m$ of the two binary mixtures showed S-shaped forms, being negative for poor and positive for rich 1,2-dichloropropane mole fractions. These show that the excess properties were shown to be negative deviation from ideality due to the strong self-association effect among 2-(2-alkoxyethoxy)ethanol molecules at an early stage of mixing, a relatively high energy then is needed to break hydrogen bonds of 2-(2-alkoxyethoxy)ethanol with an increase ofhalogenated hydrocarbon molecular at high mole fraction of 1,2-dichloropropane. The values of excess molar properties($V^E_m$ and $H^E_m$) were fitted by the Redlich-Kister equation using Nelder-Mead's simplex pattern search method. The Wilson, NRTL, and UNIQUAC models were used to correlate the $H^E_m$ values.

• Journal of Astronomy and Space Sciences
• /
• v.19 no.1
• /
• pp.31-38
• /
• 2002

The BVR CCD full light curves of ZZ Aur were obtained as one of the near-contact binary observing programs at the Sobaek Mt. Observatory during Feb. 2000 - Feb. 2001. From the present observations, three primary and seven secondary times of minimum light were obtained. The photometric solutions have been found using the Wilson and Divenny model.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.10a
• /
• pp.289-303
• /
• 2004

As needs for telecommunications services diversify, an increasingly wide range of telecommunications services is becoming available in the market. Any subscriber can find a service to satisfy his/her telecommunication requirements and competition between providers to retain heavy users is increasing. Service price reductions are one retention strategy, although price reductions for one service can affect the individual-level usage for other services. Price reductions can also be imposed on a service provider by regulation. For these reasons, understanding how price reductions affect service usage is of growing importance to the telecommunications industry for purposes of pricing and tariff development. In this paper, we develop an individual-level usage model for telecommunications services and analyze the effects on usage of a price reduction. We apply the model to age-stratified aggregate traffic data for a Korean mobile telecommunication service provider. Finally, we develop a model to support a market segmentation and price reduction strategy.

• Korean Chemical Engineering Research
• /
• v.57 no.1
• /
• pp.73-77
• /
• 2019

Isothermal (vapor + liquid) equilibrium data measurements were undertaken for the binary mixtures of (propylene oxide + 1-pentanol) system at three different temperatures (303.15, 318.15, and 333.15) K. The Peng-Robinson-Stryjek-Vera equation of state (PRSV EOS) was used to correlate the experimental data. The van der Waals one-fluid mixing rule was used for the vapor phase and the Wong-Sandler mixing rule, which incorporates the non-random two liquid (NRTL) model, the universal quasi-chemical (UNIQUAC) model and the Wilson model, was used for the liquid phase. The experimental data were in good agreement with the correlation results.

• Journal of Astronomy and Space Sciences
• /
• v.19 no.3
• /
• pp.187-196
• /
• 2002

We performed CCD photometric observations of the eclipsing binary Y Cam with a pulsating component, for 16 nights from November 2000 to May 2001 using a V filter attached to the 61-cm reflector at Sobaeksan Optical Astronomy Observatory. Our V light curve and Broglia & Marin's (1974) BV ones were analyzed with Mode 2 for a detached Roche model as well as Model 5 for a semi-detached one in the Wilson-Devinney code. From the analysis, we found the following results: 1) It is hardly discernible from only light curve synthesis which model between the detached and semi-detached ones is a real Roche model of Y Cam. 2) There exist the third light of about 2% and 3% in B and V light curves of Y Cam, respectively. 3) The light curve solution is immune from the light variation due to the pulsation of the primary component of Y cam. However, the detached model rather than the semi-detached one has slightly better fitted to the observations which were get rid of the pulsation effect. 4) The absolute dimensions of Y Cam were calculated for two Roche models.

• Korean Journal of Adult Nursing
• /
• v.19 no.4
• /
• pp.547-555
• /
• 2007

Purpose: The purpose of this study was to test a hypothetical model of health-related quality of life in patients with heart failure. The hypothetical model was derived from the Wilson and Cleary's model, the Rector's model, and published research findings. Methods: Data from 103 patients with heart failure were analyzed to determine the best multivariate health-related quality of life model given variables derived from the prior studies. The statistics programs SPSS 12.0 and LISREL 8.7 program were used for descriptive statistics and covariance structure analysis respectively. Results: The overall fitness of the path final model was good(GFI=.97, AGFI=.95, NNFI=1.06, NFI=.96, p=.96). Symptoms were directly affected by gender. HYHA Class was directly affected by only gender. Physical functioning limitation was directly affected by exercise. Health perception was directly affected by economics, symptom, and physical functioning limitation. Depression was directly affected by exercise and health perception. Heath-related quality of life was directly affected by physical functioning limitation and depression, indirectly affected by gender, economics, exercise, symptoms, NYHA Class, and health perception. This path analysis model explained 51% of health-related quality of life in patients with heart failure. Conclusion: To improve of health-related quality of life with heart failure patients, it is necessary to make nursing interventions for physical functioning and depression.

• The Korean Journal of Applied Statistics
• /
• v.32 no.4
• /
• pp.517-541
• /
• 2019

According to the OECD (2015) and UN (2017), Korea was classified as an immigration country. The designation as an immigration country means that net migration will remain positive and international migration is likely to affect population growth. KOSTAT (2011) used a model with more than 15 parameters to divide sexes, immigration and emigration based on the Wilson (2010) model, which takes into account population migration factors. Five years later, we assume the average of domestic net migration rate for the last five years and foreign government policy likely quota. However, both of these results were conservative estimates of international migration and provide different results than those used by the OECD and UN to classify an immigration country. In this paper, we proposed a stochastic projection on international migration using nonparametric model (FDM by Hyndman and Ullah (2007) and Coherent FDM by Hyndman et al. (2013)) that uses a functional data model for the international migration data of Korea from 2000-2017, noting the international migration such as immigration, emigration and net migration is non-linear and not linear. According to the result, immigration rate will be 1.098(male), 1.026(female) in 2018 and 1.228(male), 1.152(female) in 2025 per 1000 population, and the emigration rate will be 0.907(male), 0.879(female) in 2018 and 0.987(male), 0.959(female) in 2025 per 1000 population. Thus the net migration is expected to increase to 0.191(male), 0.148(female) in 2018 and 0.241(male), 0.192(female) in 2025 per 1000 population.

• Journal of Korean Academy of Nursing
• /
• v.44 no.1
• /
• pp.75-85
• /
• 2014

Purpose: The aim of this study was to explore how individual factors, physiologic factors, symptoms, environmental factors, functional status and health perception predict the quality of life (QOL) for older adults with osteoarthritis and to provide guidelines for interventions and strategies to improve QOL in these patients. The conceptual model was based on the Wilson and Cleary's Model. Methods: Data were analyzed using SPSS WIN 20.0 and AMOS 19.0 program. Results: The proposed model was a good fit for the data based on the model fit indices. Based on the constructed model, individual factors, social support, functional status and health perception were founded to have direct effects on QOL. Symptom had a indirect effect on QOL. Social support had a significant effect on QOL, and this model explained 63.6% of the variance in QOL. Conclusion: The results of this study suggest that nursing strategies to increase QOL in this population should contain social support to promote QOL and manage functional limitations and health perception.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.4
• /
• pp.315-319
• /
• 2007

A technique to model plasma processes was presented. This was accomplished by combining the backpropagation neural network (BPNN) and genetic algorithm (GA). Particularly, the GA was used to optimize five training factor effects by balancing the training and test errors. The technique was evaluated with the plasma etch data, characterized by a face-centered Box Wilson experiment. The etch outputs modeled include Al etch rate, AI selectivity, DC bias, and silica profile angle. Scanning electron microscope was used to quantify the etch outputs. For comparison, the etch outputs were modeled in a conventional fashion. GABPNN models demonstrated a considerable improvement of more than 25% for all etch outputs only but he DC bias. About 40% improvements were even achieved for the profile angle and AI etch rate. The improvements demonstrate that the presented technique is effective to improving BPNN prediction performance.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.743-750
• /
• 2002

Unsaturated soil has a possibility to induce a negative pore water pressure. Until now, saturated soil is mainly focused on the research of soil mechanics. Recently, soil mechanics is researched on two major parts such as saturated and unsaturated soil mechanics. Negative pore water pressure has a non-linear relationship with the water content changes. Soil-water characteristic curves of soil in Korea are not determined. There is no proper characteristic value such as air-entry value and residual water content. In this study, the characteristic curves of reclaimed soil, sand, and weathered granite soil were determined by laboratory tests. Air-entry value and residual water content were determined by fitting methods. Soil-water characteristic curves were estimated based on the particle-size distribution and compared with the laboratory test results. The results of soil-water characteristic curves estimation indicated that Fredlund and Wilson's model is excellent for sand and weathered granite soil. Arya and Paris's model is excellent for reclaimed soil.