• East Asian mathematical journal
• /
• v.29 no.3
• /
• pp.349-353
• /
• 2013

In this paper, we study equations over nilpotent groups of class 2. We show that there are some overgroups which contains solutions of equations with exponent sum 1 over nilpotent groups of class 2. As known, equations over a field has a solution in an extension field which contains a copy of the given field. But it is not easy to find that a solution of equations over groups. In many cases, even if equations over groups has a solution, the overgroup is not concrete but very Here we find the concrete overgroups in case of nilpotent groups.

• Journal of Korea Water Resources Association
• /
• v.34 no.6
• /
• pp.651-657
• /
• 2001

The second-order long waves generated by short wave groups propagating over a step are theoretically investigated. The diffraction of short waves is firstly formulated and the governing equations of second-order long waves are then derived by using a multiple-scale perturbation method. It is observed that free and locked long waves are generated and propagated with different velocities.

• Journal of the Korean Statistical Society
• /
• v.8 no.2
• /
• pp.117-123
• /
• 1979

Striaght-forward application of the ordinary least squares model for estimating the parameters of a simultaneous linear stochastic equations model does not provide consistent estimators due to the fact that the explanatory jointly dependent variables are correlated with the disturbances. The search for consistent estimators during the last three decades has yielded a variety of estimators which can be broadly classified into two groups, namely, limited information and full information. Both the groups fails to uilize the over-identifying restrictions in the structural equations except the one under study while the latter group succeeds; see, e.g. Srivastava(1978) for a brief review and Theil (1961) for a detail description.

• East Asian mathematical journal
• /
• v.39 no.3
• /
• pp.349-354
• /
• 2023

The motivation in this paper comes from the recent results about Bell inequalities and topological insulators from group theory. Symmetries which are interested in group theory could be mainly used to find material structures. In this point of views, we study group extending by adding one relator which is easily called an equation. So a relative group extension by a adding relator is aspherical if the natural injection is one-to-one and the group ring has no zero divisor. One of concepts of asphericity means that a new group by a adding relator is well extended. Also, we consider that several equations and relative presentations over torsion-free groups are related to zero divisors.

• Journal of Korean Biological Nursing Science
• /
• v.22 no.4
• /
• pp.260-270
• /
• 2020

Purposes: Sepsis is a critical condition in which nurses should detect clinical manifestations and provide early intervention to prevent unwanted serious conditions in the patients. The initial occurrence and management of sepsis take place in general units, but there is a lack of knowledge in nurses. The purpose of this study was to examine the effects of a case-based sepsis education program and compare the case-based education program with and without smartphone applications. Methods: A quasi-experimental pre-test-post-test design with a control group was used. We provided a case-based education program with and without smartphone applications to the nurses and tested the effects of the program on knowledge, the accuracy of sepsis assessment, and self-efficacy as outcome variables. A total of 60 nurses in general units participated. To test differences in knowledge, the accuracy of sepsis assessment, and self-efficacy regarding sepsis between the groups over time, a mixed-design ANCOVA was used for parametric analysis, and generalized estimating equations (GEE) were used for nonparametric analysis. Results: There were significant differences in knowledge, the accuracy of sepsis assessment, and self-efficacy between the groups and within the groups over time. The intervention groups treated with the case-based education program showed improved outcome variables compared to the control group. There was no difference between case-based education with the smartphone application or without the application. Conclusions: The case-based education improved knowledge, the accuracy of sepsis assessment, and self-efficacy in the care of sepsis by nurses working in the general wards. The results suggest that the case-based education program for nurses was effective and eventually improved patient health outcomes.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.3
• /
• pp.941-944
• /
• 2012

Objective: The aim of current study was to evaluate the changes of health-related quality of life (HRQoL) and its clinical, demographic and socioeconomic determinants during chemotherapy and 4 months follow-up in women with breast cancer using a repeated measures framework. Methods and Materials: A double blind cohort study was performed in 100 breast cancer patients given fluorouracil, doxorubicin and cyclophosphamide (FAC) or docetaxel, doxorubicin, cyclophosphamide (TAC) in south of Iran. HRQoL was assessed at baseline, end of chemotherapy and four months thereafter using the QLQ-C30 questionnaire from European Organization for Research and Treatment of Cancer (EORTC). Generalized estimating equations (GEE) was applied for statistical analysis. Results: The mean of age at baseline was $48.5{\pm}10.6$. 70% and 14% of patients were married and smokers, respectively, and 20% suffered from another disease besides breast cancer. The results of GEE showed that after control for baseline scores, the HRQoL significantly improved over time. Although, the patients in FAC group had higher scores than the TAC group, the differences also diminished over time. Smoking, marital status and having child affected some scales of HRQoL. None of other variables were significantly related to HRQoL. Conclusion: Although patients in TAC groups had lower level of HRQoL over 8 months follow up, they experienced faster improvement than the FAC group. This implies that in long-term, improvements in TAC group are higher than FAC. Having children was positively correlated with HRQoL. Generally, there were no demographic and socio-economic differences in HRQoL in these patients between the chemotherapeutic regimens.

• Korea journal of population studies
• /
• v.9 no.1
• /
• pp.41-53
• /
• 1986

The purpose of this paper is two-fold. One is to investigate the determinants of the demand supply of labor, and another is to project long-term demand and supply of labor. The paper consists of three parts. In the first part, theoretical models and important hypotheses are discussed: for the case of a labor supply model, issues regarding discouraged worker model, permanent wage hypothesis, and relative wage hypothesis are examined and for the case of a demand model, issues regarding estimating an employment demand equation within the framework of an inverted short-run produc- tion function are inspected. Particularly, a theoretical justification for introducing a demographic cohort variable in a labor supply equation is also investigated. In the second part, empirical results of the estimated supply and demand equations are analyzed. Supply equations are specified differently between primary and secondary labor force. That is, for the case of primary labor force groups including males aged 25 and over, attempts are made to explain the variations in participation behavior within the framework of a neo-classical economics oriented permanent wage hypothesis. On the other hand, for the case of females and young male labor force, variations in participation rates are explained in terms of a relative wage hypothesis. In other words, the participation behavior of primary labor force is related to short-rum business fluctuations, while that of secondary labor force is associated with intermediate swings of business cycles and demographic changes in the age structure of population. Some major findings arc summarized as follows. (1) For the case of males aged 14~19 and 2O~24 groups and females aged 14∼19, the effect of schhool enrollment rate is dominant and thus it plays a key role in explaining the recent declining trend of participation rates of these groups. (2) Except for females aged 20∼24, a demographic cohort variable, which captures the impact of changes in the age structure on participation behavior, turns out to show positive and significant coefficients for secondary labor force groups. (3) A cyclical variable produce significant coefficients for prime-age males and females reflecting that as compared to other groups the labor supply behavior of these groups is more closely related to short-run cyclical variations (4) The wage variable, which represents a labor-leisure trade-off turns out to yield significant coefficients only for older age groups (6O and over) for both males and females. This result reveals that unlike the experiences of other higer-income nations, the participation decision of the labor force of our nation is not highly sensitive with respect to wage changes. (5)The estimated result of the employment demand equation displays that given that the level of GNP remains constant the ability of the economy to absord labor force has been declining;that is, the elasticity of GNP with respect to labor absorption decreasre over time. In the third part, the results of long-term projections (for the period of 1986 and 1995) for age-sex specific participation rates are discussed. The participation rate of total males is anticipated to increase slightly, which is contrary to the recent trend of declining participation rates of this group. For the groups aged 25 and below, the participation rates are forecast to decline although the magnitude of decrease is likely to shrink. On the other hand, the participation rate of prime- age males (25 to 59 years old) is predicted to increase slightly during 1985 and 1990. For the case of females, except for 20∼24 and 25∼34 age groups, the participation rates are projected to decrease: the participation rates of 25∼34 age group is likely to remain at its current level, while the participation rate of 20∼24 age group is expected to increase considerably in the future (specifi- cally, from 55% in 1985 to 61% in 1990 and to 69% in 1995). In conclusion, while the number of an excess supply of labor will increase in absolute magnitude, its size as a ratio of total labor force is not likely to increase. However, the age composition of labor force is predicted to change; that is, the proportion of prime-age male and female labor force is projected to increase.

• Health Policy and Management
• /
• v.30 no.4
• /
• pp.467-478
• /
• 2020

Background: The purpose of this study is to explain the factors influencing the incurrence of catastrophic health expenditure of national health insurance households using panel data observed over a long period. Methods: The study targeted 3,652 households who had no censoring during the 11-year survey period (2007-2017) and householders whose insurance type was consistently maintained as national health insurance. Generalized estimating equations were adopted to identify factors affecting the occurrence of catastrophic health expenditure at 20%, 30%, and 40% threshold levels. A subgroup analysis was conducted by categorizing groups depending on the existence of the elderly in the household. Results: For the last 11 years, the incidence of catastrophic health expenditure in the households without the elderly decreased slightly at all threshold levels, but the households with the elderly seemed to be increased. At baseline, household type showed a statistically significant relationship with all other variables. The results of generalized estimating equations analyses show that household income was not significant at all threshold levels in the households without elderly. On the other hand, in the households with the elderly, the 2nd (odds ratio [OR], 1.33-2.05) and 3rd quintile groups (OR, 1.25-2.55) were more likely to have catastrophic health expenditure compared to the 1st quintile of household income group. Conclusion: As the amount of health expenditures relative to the ability to pay is increasing in households with the elderly, the application of an intervention followed by consistent monitoring is needed. This study found that there were differences in influencing factors according to the presence of the elderly in the households. In particular, in households with the elderly, interesting results have been drawn regarding the occurrence of catastrophic health expenditure in the near-poor, so additional research is required.

• Fashion & Textile Research Journal
• /
• v.10 no.1
• /
• pp.83-91
• /
• 2008

This study was designed to figure out the changes in elderly women's foot size and shape by aging, to propose size specification for elderly women's shoes, and to produce regression equations using representative measurements items to estimate other measurements usually hard to get. Subjects were 118 women of 30-59 years and the 227 elderly women over 60 years. Martin's anthropometry was done on the right foot of each subject for 25 items. And 11 indirect measurement items were measured on both foot printing sole outline and picture in profile taken by digital camera. For statistical analysis on the anthropometric measurements by SPSS program, analysis of variance, post-hoc test(SNK-test), crosstabulation, multiple correlation analysis, regression analysis were performed. The results of the study are as follows. Firstly, it was found that the foot figures of elderly women over 60 years were smaller in girth and width than those of below 60 years. In addition, it was revealed that a big toe and a little toe of elderly women showed a tendency concentrating to the central axis of feet. The foot index of elderly was smaller in width and girth. Secondly, foot size distribution table of elderly group showed wider size ranges and covered smaller sizes than the below the age of 60, meaning wide variation in foot size of elderly women. Thirdly, the multiple correlation analysis showed high correlation of foot length/girth to other measurements, suggesting these two items could be used as representative items for elderly women's shoe size specification as other age groups. Regression equations were produced using foot length/girth to estimate other measurements, suggesting such items could be estimated effectively and utilized in on/off-line shoe manufacturing shop as heel to big toe length, heel to little toe length, exterior malleouls width, instep girth, ankle girth, etc. These results imply prudent features of elderly women's foot as diversity of foot shape and wide size specification range should be applied for ergonomic shoe design for them.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.20 no.2
• /
• pp.212-218
• /
• 2008

A possible source of resonant problems in a harbor is long waves generated by incident wave groups. The analytical solutions of the governing equations of second-order long waves derived using a multiple-scale perturbation method consist of the locked and free long waves. The locked long waves propagate at some group velocity, whereas the free long waves propagate at the shallow-water speed. To study the resonance of free long waves, a trapezoidally varying topography is employed. With certain combinations of incident angle, water depth, and ambient current velocity, free long waves can be trapped and resonated.