• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.4
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• pp.120-128
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• 2011

Recent development of communication technology and evolution of telecommunications services, various needs of users are giving Telecom operators difficulties in discovering new services and its promotion strategies. In addition, at the launching of new services, if carriers does not consider complementary and substitution relationships with competing services or self-encroachment problem with the existing service profitability is reduced or lost in the current market. In this study, by analyzing usage pattern of telecommunications services respect to changes in supply and demand environment, the complementarity/substitutability analysis and systematic analytical framework is proposed. This study proposes approaches to establish mobile operators' business strategies and to identify new services demand.

• KDI Journal of Economic Policy
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• v.36 no.4
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• pp.171-205
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• 2014

This paper investigates the manner in which house prices affect macroeconomic variables through a house price channel by applying the method of Iacoviello (2005) to Korean data, and establishing a DSGE model with complementarity. This paper found that higher LTV ratio coupled with stronger complementarity results in the co-movement in both consumption and housing. For instance, the results show that when the LTV ratio and complementarity stands respectively at 50% and 0.42, an 1% rise in house prices increases consumption by 0.057%, and when the complementarity parameter increases to 0.52 with LTV remains unchanged at 50%, consumption rises by 0.047% per 1% increase in house prices. An increase in house prices leads credit constraints for borrowers to become more loose as value of a house rises as a collateral. The increase in household credit enables more consumer spending, eventually leading to increased consumption. A key link in which house prices are connected to macroeconomic variables is change in consumption. To put it simply, a rise in house prices leads to an increase in consumption, which consequently impacts the overall macro-economy. At this point, complementarity is found, in that the elasticity of intra-temporal substitution between housing and consumption is estimated at 0.42, which plays an important role in the house price channel by amplifying the effects of house prices on consumption.

• Journal of Microbiology
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• v.39 no.1
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• pp.49-55
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• 2001

We have developed four chicken hybridomas secreting monoclonal antibodies to induce a protective immune response against the chicken disease avian coccidiosis, caused by the intestinal parasite Eimeria acervulina. Huwever, since the amount of antibodies secreted from these hybridomas is too low or sometimes they lost their ability to produce antibodies, the hybridoma method is not satisfactory in the production of large amounts of chicken monoclonal antibodies. To bypass these problems, we applied the antibody engineering technology using polymerase chain reaction. We cloned and determined the sequences of variable domains of the four chicken monoclonal antibodies, namely, 2-1, 5D11, 13C8 and 8C3. The sequences comparison to germline sequences skewed that the gene con version mechanism might contribute to developing diversification of heavy and λ-light chains in chicken antibodies. Several pseudogene families regarded as donors in gene conversion were identified at each framework region and the complementarily determining region of λ-light chains. In addition, as expected, numerous changes of nucleotide sequences such as nucleotide substitution, insertion and deletion were found predominantly in complementarity determining regions, which are likely to be somatic hypermutations as a result of affinity maturation in antibody-producing cells.

• Journal of Korean Society of Transportation
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• v.30 no.4
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• pp.33-42
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• 2012

Recent development and penetrating expansion in ICT(Information and Communication Technology) has brought considerable improvements in transportation services. However, there is a controversial debate whether transportation and communications behave as substitutes or as complements to one another. On this subject, recent studies considered those two industries as services, but transportation and communications are broadly put for intermediary goods into other industries. Hence, it is essential to examine this issue from understanding their relationships to each other with respect to manufacturing and services. In this study, input-output tables of benchmark years from 1980 to 2005 have been analysed to explore the relationships between transportation and communications using Spearman's correlation analysis. The results show that both industries had complementary roles over the period, but, to some extent, changed into substitution roles in some categories.

• Molecules and Cells
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• v.39 no.3
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• pp.217-228
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• 2016

To generate a biobetter that has improved therapeutic activity, we constructed scFv libraries via random mutagenesis of several residues of CDR-H3 and -L3 of hu4D5. The scFv clones were isolated from the phage display libraries by stringent panning, and their antiproliferative activity against HER2-positive cancer cells was evaluated as a primary selection criterion. Consequently, we selected AH06 as a biobetter antibody that had a 7.2-fold increase in anti-proliferative activity ($IC_{50}$: 0.81 nM) against the gastric cancer cell line NCI-N87 and a 7.4-fold increase in binding affinity ($K_D$: 60 pM) to HER2 compared to hu4D5. The binding energy calculation and molecular modeling suggest that the substitution of residues of CDR-H3 to W98, F100c, A101 and L102 could stabilize binding of the antibody to HER2 and there could be direct hydrophobic interactions between the aromatic ring of W98 and the aliphatic group of I613 within HER2 domain IV as well as the heavy and light chain hydrophobic interactions by residues F100c, A101 and L102 of CDR-H3. Therefore, we speculate that two such interactions were exerted by the residues W98 and F100c. A101 and L102 may have a synergistic effect on the increase in the binding affinity to HER2. AH06 specifically binds to domain IV of HER2, and it decreased the phosphorylation level of HER2 and AKT. Above all, it highly increased the overall level of p27 compared to hu4D5 in the gastric cancer cell line NCIN82, suggesting that AH06 could potentially be a more efficient therapeutic agent than hu4D5.

• Journal of Labour Economics
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• v.29 no.1
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• pp.129-152
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• 2006

The purpose in this study is to analyze the effect of expected public pension assets (or social security wealth) and retirement incentives on retirement behaviors of two wage earners households. For the purpose of the study, an empirical analysis was conducted. In the empirical step, it was found that the empirical results were significant for men, but not for women namely, statistically asymmetric if behaviors of two couples are interdependent. The cause for the statistically asymmetric results were then determined. The Bivariate Probit model was used for estimation in the first step and the KLIPS(Korean Labor and Income Panel Study) was used as data for estimation. According to the empirical analysis, the results showed statistically significant asymmetry for men, however not for women, in expected public pension assets and other retirement incentives, non-wage assets, age difference, spouse's health status, spouse's monthly wages per hour and aging of their spouse In this study, cause of statistically asymmetric result in asymmetric complementarities of leisure of couples were found, then explained through different methods of comparison from the most recent studies. First, spouse's cross wage elasticity of self leisure demand(retirement) was calculated and determined whether complementarities of leisure of couples is positive or negative. Then, the degree of complementarities of leisure was distinguished in comparison with the relative size of two cross elasticities. Thus, men have relatively strong complementarities of leisure. But for women, it may roughly cancel out due to the substitution effect and the income effect. Therefore, women have relatively weak complementarities of leisure.

• 한국노년학
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• v.38 no.4
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• pp.1035-1055
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• 2018

The purpose of this study is to investigate the relationship between public care and family care. Public care for older adults began in 2008 with the implementation of the Long-Term Care insurance in South Korea. Although the expansion of public care has the purpose of reducing the care burden for the family, it is not easy to say whether the developments of public care system reduce the amount of family care for older family members. Theoretically, public care and family care are expected to have various relationships depending on the degree of the role and function(substitution, hierarchical compensatory, task specific, supplementation, complementarity). And literatures have showed inconsistent results depending on the country, data, and methods. In this study, we analyzed the relationship between two care types focusing on home care services for older persons. Analyses were based on data from the second(2008) to sixth(2016) waves of Korean Longitudinal Study of Ageing(KLoSA). To investigate elderly care dynamics in the households, we pooled the data for four changes between two periods(2008-2010, 2010-2012, 2012-2014, and 2014-2016). This study used an analytic sample of 262 older adults, who are aged 55 over and experienced public care at least one point of time. We used Fixed-Effects(FE) model to analyze the differences within the same individuals under the condition that time-invariant unobserved factors are controlled. This study distinguished the cases of entry into public care and other cases of exiting public care. The results showed that older people who are dependent on public care are less dependent on family care than before. In both entry and exit groups, negative relations were maintained, but in the entering stage of public care, the degree of negative relations was relatively small, whereas in the stage of maintaining or departing from public care, relatively negative relations were strong. At the beginning periods, even though public care increased, family care did not decrease significantly. On the other hand, at the time of ending public care and relying on family care, family care increased significantly. The results of this study show that the relationship between public care and family care is close to hierarchical compensatory model and varies according to the stage of caring transition. Also, it was found that the cases of transition from public care to family care have the biggest burden of elderly care than other groups.