• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.257-264
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• 1989

In order to study spatial variability of soil chemical properties across the land-partitioned boundary on Hwadong silt clay loam soil (Fine clayey, mixed, mesic family of Aquic Hapludalfs) in the experimental fie ld of the wheat and Barley Research Institute in Suwon, all measured data were analyzed by means of kriging, fractile diagram, smooth frequency distribution, and autocorrelation. Sampling for soil chemical property analysis was made at 225 intersections of 15x 15 grid with 10m interval from three soil depths (0-10cm, 25-35cm, 50-60cm) in the seven patitioned fields. 1. The coefficient of variance (CV) of various chemical properties varied from 5.4 to 72.7%. Soil pH was classified into the low variation group with CV smaller than 10%, while the other chemical properties belonged to the medium variation group with C.V. between 10 and 100% 2. The approximate number of soil samples for the determination of various chemical properties with error smaller than 10% were two for pH, ten for CEC, 15 for exchangeable Ca, 32 for total nitrogen content, 39 for exchangeable Mg, 40 for exchangeable K, 61 for exchangeable Na, 82 for organic matter content, 212 for available phosphate,. 3. Smooth frequency distribution and fractile diagram showed that available phosphate was in log-normal distribution while others were in normal distribution. 4. Serial correlation analysis revaled that the soil chemical properties had spatial dependence between two nearest neighbouring grid points. Autocorrelation analysis of chemcial properties measured between the serial grid points in the direction of south to north following land-partitioned boundary showed that the zone of influence showing stationarity ranged from 20 to 50m. In the direction of east to west accross land-partitioned boundary, the autocorrelogram of many chemical properies showed peaks with the periodic interval of 30m, which were similar to the partitioned land width. This reveals that the land-partitioned boundary causes soil variability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.469-481
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• 2016

The number of single households in Korea has been sharply increasing due to dissolution of the family community and changes in housing culture. Therefore, there is a need to develop a plan for diagnosis of changes in the housing market in response to a rapid increase of single household to suggest a proper direction of housing policy. This study was conducted to clarify the factors influencing housing occupancy type targeting a single adult household. To accomplish this, a cross-sectional analysis was conducted using the multi-nominal logit model and the Korea Welfare Panel's 9th survey materials. Occupants of ingle households in their 20s and 30s were found to be much poorer than those in their 40s, or older. Additionally, single household in their 20s and 30s, the characteristic of a household having an influence on the choice of housing occupancy type showed a result in a different direction even from the same household characteristic of those in their 40s, or older. Finally, the characteristics of occupants of single households in their 20s and 30s showed room for improvement through public support. Overall, the results of this study implied the need to inquire into the government's periodic support in more diverse ways.

• The Korean Journal of Financial Management
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• v.20 no.2
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• pp.41-72
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• 2003

The purposes of this paper are to build theoretical and empirically testable model to identify determining factors of ownership structure, and to analyze this model empirically using th Korea Stock Exchange panel data, and to test the impact of opening the stock market on the determinants of ownership structure. The determining factors of ownership structure identified in this paper include debt ratio, dividend, asset characteristics, profitability, growth business risk, size, institutional investors and chaebol-non chaebol dummy variable. Empirical panel estimation test reveals that this model can explain about $9\sim11%$ of the cross sectional variance in the equity ratio of large shareholders. The reasons that this model has too explanatory power are that some variables were measured with errors, and that there were some omitted variables in tested model. The regression results on the model variables ar generally in line with predictions. But the coefficient estimates on size is never significant. And it appears that the exogenous variable which explains opening the stock market has positive effect on the determinants of ownership structure.

• The Journal of Information Technology
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• v.1 no.2
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• pp.209-227
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• 1998

This study examines the relation between accruals components of earnings and stock return. Earnings are decomposed into four components: discretionary accruals, nondiscretionary accruals, nondiscretionary income and cash flow from operations. Because reported earnings in financial statement consist of cash flow from operations plus total accruals. We decompose total accruals into a discretionary accruals and a nondiscretionary accruals separately, This paper examines the incremental informational content of discretionary accruals and nondiscretionary accruals components of net income by regressing return on earnings'components in multivariate models. The empirical analysis is conducted on a sample of 1,580 firm-years comprising 158 firms during 1984-1995. Discretionary accruals are obtained by decomposing total accruals into discretionary and nondiscretionary accruals components, using a pooled variation of the Jones model(1991). These findings suggest that the discretionary accruals(measured using a variation the Jones model) is priced by the stock market. Specifically, the discretionary accruals and cash flow from operations are positively associated with the stock return, and also nondiscretionary income, discretionary accruals are positively associated with the stock return. While this result is consistent with the market prices the discretionary accruals because it captures value-relevant information. Additional test report evidence consistent with nondiscretionary accruals conveying information about the stock return.

• Journal of Korea Water Resources Association
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• v.51 no.8
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• pp.655-664
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• 2018

The riverbed material survey is to investigate the particle size distribution, specific gravity, porosity, etc. as basic data necessary for river channel plan such as calculation of sediment transport and change of river bed. In principle, the survey spots are 1 km interval in the longitudinal direction of the river and 3 points or more in the 1 cross section. Therefore, depending on longitudinal length of the river to be investigated, the number of surveyed sites is very large, and the time and cost for the investigation are correspondingly required. This study is to compare the particle size analysis method with the volumetric method and the image analysis method in work efficiency and cost and to examine the applicability of the image analysis method. It was confirmed that the diameter of the equivalent circle converted by the image analysis method can be applied to the analysis of bed material particle size. In the gravel stream with a particle size of less than 10 cm and a large shape factor, the analytical result of the bed material by the image analysis method is accurate. However, when the shape factor decreases as the particle size increases, the error increases. In addition, analysis results of the work efficiency and cost of the volume method and the image analysis method showed a reduction of about 80%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.509-516
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• 2020

Since the 1960s, many rivers have been polluted and destroyed due to river repair projects for economic development and the covering of small rivers due to urbanization. Many studies have analyzed rivers using measured river topographic factors, but surveying is not easy when the flow rate changes rapidly, such as during a flood. In addition, the previous research has been mainly about the cross section of a river, so information on the longitudinal profile is insufficient. This research used informational entropy theory to obtain an equation that can calculate the average river slope, river slope, and river longitudinal elevation for a river basin in real time. The applicability was analyzed through comparison with measured data of a river's characteristic factors obtained from a river plan. The parameters were calculated using informational entropy theory, nonlinear regression analysis, and actual data. The longitudinal elevation entropy equation for each stream was then calculated, and so was the average river slope. All of the values were over 0.96, so it seems that reliable results can be obtained when calculating river characteristic factors.

• The Journal of Information Technology
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• v.7 no.3
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• pp.19-36
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• 2004

This study examines the relation between accruals components of earnings and stock return. Earnings are decomposed into four components: discretionary accruals, nondiscretionary accruals, nondiscretionary income and cash flow from operations. Because reported earnings in financial statement consist of cash flow from operations plus total accruals. We decompose total accruals into a discretionary accruals and a nondiscretionary accruals separately. This paper examines the incremental informational content of discretionary accruals and nondiscretionary accruals components of net income by regressing return on earnings' components in multivariate models. The empirical analysis is conducted on a sample of 1,580 firm-years comprising 158 firms during 1991-2003. discretionary accruals are obtained by decomposing total accruals into discretionary and nondiscretionary accruals conponents, using a pooled variation of the Jones model(1991). These findings suggest that the discretionary accruals(measured using a variation the Jones model) is priced by the stock market. Specifically, the discretionary accruals and cash flow from operations are positively associated with the stock return, and also nondiscretionary income, discretionary accruals are positively associated with the stock return. While this result is consistent with the market prices the discretionary accruals because it captures value-relevant information. Additional test report evidence consistent with nondiscretionary accruals conveying information about the stock return.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.117-125
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• 2011

River bed variation drops storage capacity of dams and reservoirs, and furthermore deteriorates safety of banks and peers. Therefore, understanding of bed variation is important to use and manage river water. Study section is downstream part of Ji- Cheon nearby Ji-Cheon Bridge which is located in Gum river basin. The river surveying at fourteen places with the length of 1,320m were undertaken on November 7, 2003 and September 24, 2004, and the results of river surveying were analyzed for the study. Real bed variation was compared with the simulation results of HEC-6 and GSTARS 3.0. Cross section data for the simulation of HEC-6 and GSTARS3.0 were composed of the basis of river surveying data on November 7, 2003. Hydrological data were acquired from Gu-Ryong watermark located at Ji-Chun Bridge. The research results revealed that when using Toffaleti equation, simulation results of two models were similar to the real bed variation. The bed variation simulated by using GSRARS 3.0 with only one stream tube was similar to the real bed variation. The bed variation simulated by using two models(HEC-6 and GSTRARS 3.0) with Toffaleti equation was also similar to the real bed variation. Therefore, it is expected that HEC-6 and GSTARS 3.0 models have applicability to predict the bed variation at the downstream of Ji-Cheon.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.25-36
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• 2021

This study analyzed the causes of flood accidents, such as isolation and lost footing accidents in Dorimcheon, to provide legal and institutional improvements. For cause analysis, Field Investigation, Stakeholder Interview, Report, manual, Law et al. Review, Analysis of water level change characteristics, automatic alarm issuance standard level analysis, and evacuation time according to river control were evaluated. Dorimcheon has the characteristics of a typical urban river, which is disadvantageous in terms of water control. In addition, the risk of flood accidents is high because the section where fatal accidents occur forms sharply curved channels. Tripping and isolation accidents occur in the floodplain watch and evacuation stage, which is the stage before the flood watch and warning is issued. Because floodplain evacuation is issued only when the water level rises to the floodplain, an immediate response according to the rainfall forecast is essential. Furthermore, considering that the rate of water level rise is up to 2.62 cm/min in Sillimgyo 3 and Gwanakdorimgyo, sufficient evacuation time is not secured after the floodplain watch is issued. Considering that fatal accidents occurred 0.46 m below the standard water level for the flood watch, complete control is very important, such as blocking the entry of rivers to prevent accidents. Based on these results, four improvement measures were suggested, and it is expected to contribute to the prevention of Tripping and Isolation Accidents occurring in rivers.

• 한국노년학
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• v.32 no.4
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• pp.1101-1118
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• 2012

The purpose of this study is to examine which factors determine self-rated health(SRH) among Korean elderly focusing on gender differences. To achieve this purpose, it uses the Hallym Longitudinal Study of Aging, wave 4 in 2009. Participants aged 65 and over from wave 4 were selected(N=986, male 407, female 579). From wave 4, all variables were selected except for respondents' education which was from wave1. In analyses, $x^2$ or t-test were conducted to examine whether independent variables significantly differ by SRH. Then, since a dependent variable consisted of two categories-being healthy or not being healthy, logistic regressions were run. What makes gender differences in the link of independent variables to SRH were 75-84 age group, education, and IADLs. For females, 75-84 age group rated their health as worse compared to 65-74 age group, but this age group did not have significant effect on SRH for males. Females graduating from junior high school were more likely to higher rate their health compared to their counterparts. However, education was not significant for males. Instrumental activities of daily living(IADLs) is one of variables affecting SRH by making gender differences. Female having problems with IADLs were more likely to be significantly negatively rate their health compared to males. Through focusing on age, education, IADLs making gender difference in evaluating health, governments needs to support males and females differently.