• The Korean Journal of Applied Statistics
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• v.32 no.4
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• pp.463-483
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• 2019

Since 2000, Korea's total fertility rate (TFR) has been different from that of Japan, Germany, and France where irreversible constants do not change easily in the fertility rate increasing or decreasing phase. It also showed a gradual increase from the minimum fertility level 1.08 in 2005 to 1.23 in 2015, which dropped to 1.17 in 2016, to 1.05 in 2017 and to 0.98 in 2018. This is similar to a double dip in the economic status of a recession. This paper investigates such a TFR increase and decrease factor that predicts the number of births affecting TFR, examines trends in the proportion of married and marital fertility rate broken down by TFR decomposition method. We also examined how these changes affect the change in TFR. According to the results, the number of births is estimated to be between 320 and 330 thousand in 2018, 300 thousand in 2020, 230 and 240 thousand in 2025. The proportion of married is steadily decreasing from 1981 to 2025, and the marital fertility rate is predicted to decline until 2002, then increase from 2003 to 2016 and decrease from 2017 to 2025. Finally, the trend of TFR in terms of number of births, TFR decomposition and statistical model is expected to show 0.98 in 2018, 0.93 to 1.11 in 2020 and 0.76 to 1.08 in 2025.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.53-62
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• 2020

The COVID 19 pandemic has led to a new global recession and is still causing a lot of issues because of the delays in the employment of people. This scenario has severe consequences for many countries' labor markets in the world. This problem's complexity and importance requires an integrated method of subjective and objective evaluation rather than intuitive decisions. This research aims to investigate sustainable indexes for assessing the unemployment problem by using a Multi-Criteria Decision-Making Model (MCDM). Grey theory and Decision Making Trial and Evaluation Laboratory (GDEMATEL) are deployed to transform the experts' opinions into quantitative data. The analysis based on 20 crucial criteria is employed to determine the weights of sustainability of unemployment problems. The results revealed that the top ten of determinants are Economic growth, Industrialization, Foreign direct investment, Real GDP per capita, Education level, Trade Openness, Capacity Utilization Rate, Urbanization, Employability skills, Education system expansion, which have the most significant effects on the unemployment rate under COVID 19 impacts. Furthermore, GDEMATEL could effectively assess the sustainable indicators for unemployment problems in "deep and wide" aspects. The study proposes the Grey MCDM model, contributes to the literature, provides future research directions, and helps policymakers and researchers achieve the best solutions to the unemployment problems under "economic shocks."

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.574-578
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• 2003

There are so many methods to estimate the groundwater recharge. These methods can be categorized into four groups. First groupis related to the water balance analysis, second group is concerned with baseflow/springflow recession, and third group is interested in some types of tracers; environmental tracers and/or temperature profile. The limitation of these types of methods is that the estimated results of recharge are presented in the form of an average over some time period. Forth group has a little different approach. They use the time series data of hydraulic head and specific yield evaluated from field test, and the results of estimation are described in the sequential form. But their approach has a serious problem. The estimated results in forth typeof methods are generally underestimated because they cannot consider the discharge phase of water table fluctuation coupled with the recharge phase. Ketchum el. at. (2000) proposed calibrated method, considering recharge- and discharge-coupled water table fluctuation. But the dischargeis considered just as the areal average with discharge rate. On the other hand, there are many methods to estimate the source wavelet with observed data set in geophysics/signal processing and geophysical methods are rarely applied to the estimation of groundwater recharge. The purpose this study is the evaluation of the applicability of one of the geophysical method in the estimation of sequential recharge rate. The applied geophysical method is called minimum entropy deconvolution (MED). For this purpose, numerical modeling with linearized Boussinesq equation was applied. Using the synthesized hydraulic head through the numerical modeling, the relative sequenceof recharge is calculated inversely. Estimated results are very concordant with the applied recharge sequence. Cross-correlations between applied recharge sequence and the estimated results are above 0.985 in all study cases. Through the numerical test, the availability of MED in the estimation of the recharge sequence to groundwater was investigated

• Korean Journal of Social Welfare
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• v.35
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• pp.179-203
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• 1998

Since the end of 1997, the Korean economy has been in deep recession; the unemployment rate has rocketed to 6.7% and the economic growth rate has dropped to -3.8% in the first quarter of 1998. Facing with this mass unemployment, the Korean Government launched comprehensive countermeasures against mass unemployment.. However, these have been in severe criticism from the outset on account of ineffectiveness and impracticability. It is in this regard that this paper purports to design a socially acceptable and financially feasible social safety net by reforming the Livelihood Aid Programme. For this purpose, chapter 3 defines the concept of social safety net, and chapter 4 reviews the social safety net programmes sponsored by World Bank and IMF in the Third World countries and Eastern European countries. Chapter 5 proposes the Three Step Approach in designing the social safety net in Korea.

• Korean Journal of Construction Engineering and Management
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• v.14 no.5
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• pp.103-112
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• 2013

After 1990s, the influence of construction industry has been decreased on national economy and construction business condition has been changed on economic recession and boom repeatedly. Larger fluctuation of business condition makes a forecast of it to be more difficult. Uncertainty in business prediction results in damages on construction companies and stakeholders. Therefore, study on forecasting a construction business is very important. This study suggests the Construction Industry Production Index(CIPI) to predict a construction business in consider of temperature effects. The results show that construction business is much influenced by temperature effects certainly and GDP. With the CBFM, this study examines CIPI for 2013 with two scenarios: 1)with GDP growth rate of 3.5% 2)with GDP growth rate of 2.4%. Thus, CIPI would be used as the economic state index to display the construction business conditions. Also, CIPI will be utilized as basic methodology in the impact of climate change in the construction industry.

• Korean Journal of Environment and Ecology
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• v.16 no.3
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• pp.239-248
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• 2002

This study was conducted to investigate the hydrological characteristics of groundwater level change and rainfall-runoff processes at the Moojechi Bog located in Mt. Jeungjok, Ulsan. The average runoff rate of bog was 0.58 which is similar to that of general mountainous watershed. In the short term hydrograph, runoff was increased slowly and It took a long time to arrive peak flow. After that time, the decreasing pattern of runoff was slower than that of general mountainous watershed. In case of the long term water budget, the Moojechi Bog had a abundant base flow and runoff was continued in spite of non rainfall period. The groundwater level was arrived peak flow immediately after rain stop but was decreased very slowly until the next rain. The change pattern of long term groundwater level was very similar to that of the amount of rain and discharge. The higher rainfall intensity was, the lower slope of recession curve on the groundwater level was and the longer rainfall duration was, the longer peak flow was. Judging from these results, Moojechi bog could be evaluated to have a constant groundwater level.

• Journal of Periodontal and Implant Science
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• v.49 no.2
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• pp.90-104
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• 2019

Purpose: The aim of this study was to evaluate clinical and radiographic changes and the survival rate after periodontal surgery using deproteinized bovine bone mineral (DBBM) with 10% collagen or DBBM with a collagen membrane in endo-periodontal lesions. Methods: A total of 52 cases (41 patients) with at least 5 years of follow-up were included in this study. After scaling and root planing with or without endodontic treatment, periodontal regenerative procedures with DBBM with 10% collagen alone or DBBM with a collagen membrane were performed, yielding the DBBM + 10% collagen and DBBM + collagen membrane groups, respectively. Changes in clinical parameters including the plaque index, bleeding on probing, probing pocket depth, gingival recession, relative clinical attachment level, mobility, and radiographic bone gains were evaluated immediately before periodontal surgical procedures and at a 12-month follow-up. Results: At the 12-month follow-up after regenerative procedures, improvements in clinical parameters and radiographic bone gains were observed in both treatment groups. The DBBM + 10% collagen group showed greater probing pocket depth reduction ($4.52{\pm}1.06mm$) than the DBBM + collagen membrane group ($4.04{\pm}0.82mm$). However, there were no significant differences between the groups. Additionally, the radiographic bone gain in the DBBM + 10% collagen group ($5.15{\pm}1.54mm$) was comparable to that of the DBBM + collagen membrane group ($5.35{\pm}1.84mm$). The 5-year survival rate of the teeth with endo-periodontal lesions after periodontal regenerative procedures was 92.31%. Conclusions: This study showed that regenerative procedures using DBBM with 10% collagen alone improved the clinical attachment level and radiographic bone level in endo-periodontal lesions. Successful maintenance of the results after regenerative procedures in endo-periodontal lesions can be obtained by repeated oral hygiene education within strict supportive periodontal treatment.

• Journal of Korea Water Resources Association
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• v.38 no.7 s.156
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• pp.517-526
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• 2005

In Korea, the methods of estimating groundwater recharge can categorized into two groups. One is baseflow separation method by means of groundurater recession curve, the other is water level fluctuation method by using the data from groundwater monitoring wells. Baseflow separation method is based on annual recharge and lumped concept, and water-table fluctuation method is largely dependent on monitoring wells rather than water budget in watershed. However, groundwater recharge rate shows the spatial-temporal variability due to climatic condition, land use and hydrogeological heterogeneity, these methods have various limits to deal with these characteristics. For this purpose, the method of estimating daily recharge rate with spatial variability based on distributed rainfall-runoff model is suggested in this study. Instead of representative recharge rate of large watershed, the subdivided recharge rate with heterogeneous characteristics can be computed in daily base. The estimated daily recharge rate is an advanced quantity reflecting the heterogeneity of hydrogeology, climatic condition, land use as well as physical behaviour of water in soil layers. Therefore, the newly suggested method could be expected to enhance existing methods.

• Korea journal of population studies
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• v.33 no.2
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• pp.113-136
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• 2010

Low fertility has become quite commonplace worldwide, and Europe has experienced below replacement fertility for several decades. In addition, lowest-low fertility, defined as period total fertility rate below 1.3, has rapidly spread in Europe during the 1990s and is likely to expand further. After the turn of century, lowest-low fertility started spreading in Eastern Asia. Korea's TFR of 1.19 in 2008 is lower than most European countries, although it is higher than the Hongkong(1.02) and Taiwan(1.09). The purpose of this paper is to examine the socioeconomic determinants of lowest-low fertility in Korea. In doing so, this paper discusses the effects of female labour force participation, labour instability on family formation and fertility. The data includes female labour force participation rate, unemployment rate, age at first marriage, and total fertility rate from 1980 to 2008. First, the economic recession hindered young people's economic independence and propensity to marry. Married couples were also depressed with uncertainty toward the future and avoided to have children. Second, the growth in female labor force participation had a negative impact on fertility, under the low level of compatibility between women's work and childrearing. Moreover, this paper argues that the rising cost of children including public and private educational costs is thought to be the main reason of the recent low fertility in Korea. Policy implications and some comments on population policies are also presented in the final section.

• Korean Journal of Social Welfare Studies
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• v.43 no.2
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• pp.141-178
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• 2012

Although the rate of self-employment is high in Korean labor market and the rate gap between age groups is high, few studies have addressed on the effects of push factors on transition into self-employment across age groups. The goal of this research is to determine if push factors exert different effects on the self-employment decisions across age groups. There is interest in testing push hypothesis and pull hypothesis. The Korean Labor and Income Panel Study wave 6~11 is used to test this study's hypothesis. The main contribution of the paper is that in case of high unemployment, the probability of transition into self-employment increases. It is consistent with the push hypothesis. Many people are forced to become self-employed person due to the high rate of unemployment and limited occupational choice rather than the role of entrepreneurship. By age subgroup, the transition into self-employment of the ages of 30 and 49 is high. In addition, people at 40-49 years of age are more likely to become self-employed as a response of inadequate job opportunities. It provides the evidence that the self-employment is not a matter of special age group in that people in the 30 to 49 year old age group whose economic activities are vigorous move into marginalized labor market. Furthermore, it seems to be threatened the employment's stability of the prime age in that even people who are age 40-49 years of age are pushed into self-employment because of the recession.