• Journal of Wetlands Research
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• v.23 no.4
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• pp.287-295
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• 2021

As facilities such as dam reservoir wetlands and agricultural irrigation reservoir wetlands are built, sedimentation occurs over time through erosion, sedimentation transport, and sediment deposition. Sedimentation issues are very important for the maintenance of reservoir wetlands because long-term sedimentation of sediments affects flood and drought control functions. However, research on resignation has been estimated mainly by empirical formulas due to the lack of available data. The purpose of this study was to calculate and compare the sediment deposition rate by developing a multiple regression model along with actual data and empirical formulas. In addition, it was attempted to identify potential causes of collapse by applying it to 64 reservoir wetlands that suffered flood damage due to the long rainy season in 2020 due to reservoir wetland sedimentation and aging. For the target reservoir, 10 locations including the GaGog reservoir located in Miryang city, Gyeongsangnam province in South Korea, where there is actual survey information, were selected. A multiple regression model was developed in consideration of physical and climatic characteristics, and a total of four empirical formulas and sediment deposition rate were calculated. Using this, the error of the sediment deposition rate was compared. As a result of calculating the sediment deposition rate using the multiple regression model, the error was the lowest from 0.21(m³km²/yr) to 2.13(m³km²/yr). Therefore, based on the sediment deposition rate estimated by the multi-regression model, the change in the available capacity of reservoir wetlands was analyzed, and the effective storage capacity was found to have decreased from 0.21(%) to 16.56(%). In addition, the sediment deposition rate of the reservoir where the overflow damage occurred was relatively higher than that of the reservoir where the piping damage occurred. In other words, accumulating sediment deposition rate at the bottom of the reservoir would result in a lack of acceptable effective water capacity and reduced reservoir flood and drought control capabilities, resulting in reservoir collapse damage.

• Land and Housing Review
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• v.14 no.1
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• pp.47-66
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• 2023

This study reviews prior studies on the residential environment characteristics, residential satisfaction, residential ownership consciousness and housing movement of MZ generation and analyze the structural equation models using the 2020 Korea Housing Survey data. Using 14 residential characteristics based on three classifications, we explore the effects on residential satisfaction, residential ownership consciousness, and housing movement. The empirical results are summarized as follows. First, based on factor analysis with Varimax of principal component analysis, parking facility items were excluded from the analysis by hindering validity, and as a result, KMO was 0.925 and Bartlett's test result showed a significant probability of less than 0.01. This indicates that the factor analysis model was suitable. Second, the results of the structural equation analysis for the MZ generation show that the surrounding environment, which is a potential variable of the residential environment characteristics, was statistically significant, but the accessibility and convenience were not statistically significant. Third, we find that the higher the satisfaction with the accessibility of commercial facilities, the more significant the sense of housing ownership appears. This suggests that the younger generation such as the MZ generation has a stronger desire for consumption. Fourth, the overall housing satisfaction of the MZ generation was significant for housing movement, but not for housing ownership. Compared to the industrialized generation, the baby boom generation, and the X generation, MZ generation shows distinct factors for housing satisfaction, housing ownership, and housing movement. Therefore, the residential environment characteristics of the residential survey should be improved and supplemented following the trend of the times. In addition, the government and local governments should prioritize actively participating in the housing market that suits the environment and characteristics of the target generation. Finally, our study provides implications regarding the need for housing-related research on how differ in special temporal situations such as COVID-19 in the future.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.1-15
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• 2010

This study analyzed the change of flowout and suspend solid in Andong and Imha basin according to the climate change to develop evaluation index about turbid water occurrence possibility and to support the countermeasures for turbid water management using GIS-based Soil and Water Assessment Tools (SWAT). MIROC3.2 hires model values of A1B climate change scenario that were supplied by Intergovernmental Panel on Climate Change (IPCC) were applied to future climage change data. Precipitation and temperature were corrected by applying the output value of 20th Century Climate Coupled Model (20C3M) based on past climate data during 1977 and 2006 and downscaled with Change Factor (CF) method. And future climate change scenarios were classified as three periods (2020s, 2050s, 2080s) and the change of flowout and suspended solid according to the climate change were estimated by coupling modeled value with SWAT model. Flowout and suspended solid of Andong and Imha basin in 2020s, 2050s, and 2080s were simulated as increasing compared with standard year (2006). Also, as the result of seasonal change, flowout and suspended solid of Andong and Imha basin in spring, autumn, and winter showed as increasing compared with standard year. And them of Andong and Imha basin in summer were analyzed as decreasing compared with standard year.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.1023-1031
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• 2014

This study is conducted to evaluate the supply effectiveness of the Long-term Secured Public Rental Housing (LSPRH) program implemented by the City of Seoul since March, 2012. To estimate the residential intention of potential applicants for the housing program, two logistic regression models of residential intention are estimated based on the residential characteristics of real residents. The purpose of this model estimation is to find out factors influencing the supply of LSPRH and thus to suggest the ideas for improving the effectiveness of the rental housing program operation. The analysis result shows that financial condition, income level, and public support are the major determinants for selecting LSPRH. It is also revealed that those who are currently living in rental housing or living in a house more expensive than those in nearby areas have higher residential intention for the LSPRH program. The result also presents that some problems associated with the traditional rental housing programs - such as visually recognizable low-quality exterior building design or the concentration of rental housing on limited spots - could be solved by this new type of public housing program. Lastly, one interesting finding different from previous research is that people with the intention to move into either traditional rental housing or LSPRH do not necessarily prefer a more spacious house than their current rental house.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.501-510
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• 2014

Volcanic eruptions alone may lead to serious natural disasters, but the associated release of water from a caldera lake may be equally damaging. There is both historical and geological evidence of the past eruptions of Mt. Baekdusan, and the volcano, which has not erupted for over 100 years, has recently shown signs of reawakening. Action is required if we are to limit the social, political, cultural, and economic damage of any future eruption. This study aims to identify the area that would be inundated following a volcanic flood from the Cheon-Ji caldera lake that lies within Mt. Baekdusan. A scenario-based numerical analysis was performed to generate a flood hydrograph, and the parameters required were selected following a consideration of historical records from other volcanoes. The amount of water at the outer rim as a function of time was used as an upper boundary condition for the downstream routing process for a period of 10 days. Data from the USGS were used to generate a DEM with a resolution of 100 m, and remotely sensed satellite data from the moderate-resolution imaging spectroradiometer (MODIS) were used to show land cover and use. The simulation was generated using the software FLO-2D and was superposed on the remotely sensed map. The results show that the inundation area would cover about 80% of the urban area near Erdaobaihezhen assuming a 10 m/hr collapse rate, and 98% of the area would be flooded assuming a 100 m/hr collapse rate.

• Environmental and Resource Economics Review
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• v.24 no.1
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• pp.1-53
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• 2015

In environmental policy areas, a greater use of economic instruments (EIs) has recently been observed in many countries. However, EIs are heterogeneous policy tools. The textbook case of a Pigouvian tax is far from widely used, mainly due to the information requirements and other structural and institutional constraints. The successful implementation of EIs might heavily depend on pre-existing structural and institutional conditions. Moreover, these institutional conditions are particularly unfavorable in developing countries. Using a simple analytical general equilibrium model, this paper examines how these constraints affect the welfare gain from the introduction of environmental taxes in developing countries. First, this paper solves for the second-best optimal Pigouvian tax and output tax in the presence of a distortionary tax on market use of labor. The result confirms that an environmental output tax achieves a socially-efficient level of emissions in the least-cost manner only if the nature of the linkage between the tax base and the environmental damage is fixed. Second, incorporating structural and institutional constraints into the model through a set of parameter values from China and the US, this paper calculates the net welfare effects of either using the ideal Pigouvian tax or instead using an output tax. The numerical simulation results show that the net welfare gain from the use of an ideal Pigouvian tax could be more than six times larger than that of an output tax in developing countries. On the other hand, the welfare gain is only 50 percent in developed countries. This means that the potential welfare disadvantage from using output taxes instead emissions tax for environmental purposes could be much greater in the case of developing countries.

• Korea Real Estate Review
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• v.28 no.1
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• pp.53-63
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• 2018

This paper shows that the value of land can vary based on the future availability of the land. According to the Korean principles of land appraisal by the Ministry of Land, Infrastructure, and Transport (MOLIT), the value of a piece of land is derived mainly from the latter's fertility level or local environment. In practice, however, the values of lands may vary even though their fertility level is invariant. This paper investigates a fundamental question for many professional appraisers who argue that appraisal practices are different from the principles of appraisal. It highlights the appraisal practices for agricultural and forestry lands, which have similar agricultural productivity levels or environmental conditions. It is shown in this paper that even though the fertility level of lands is invariant, the values of lands may vary based on their locations. Therefore, this can complement the principles of land appraisal. In this paper, real cases in local areas in Gapyeong County, Kyounggi province are investigated. It can be seen from the cases in the local areas that two agricultural lands may have different values based on their locations even though they have almost similar fertility levels (e.g., their physical distance from each other is less than 0.5 km but their values differ by around 19%). This paper thus argues that the value of a piece of land can be determined by its availability.

• Korean Journal of Ecology and Environment
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• v.51 no.3
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• pp.221-233
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• 2018

This study was carried out to predict the current and future potential distribution and to identify the factors affecting potential distribution of 7 plants(Lamium amplexicaule L., Trigonotis peduncularis(Trevir.) Benth. ex Hemsl, Capsella bursa-pastoris (L.) L. W. Medicus, Taraxacum officinale Weber, Veronica persica Poir., Conyza sumatrensis E. Walker, Hypochaeris radicata L.) selected as indicators for climate change in agricultural ecosystem. We collected presence/absence data of 7 indicator plants at 108 sites in South Korea and applied the Maxent model. According to future climate scenario, the distribution area of C. bursa-pastoris(L.) L. W. Medicus, T. officinale Weber, and V. persica Poir. was expected to be reduced, but the distribution range was to be maintained. The distribution areas and range of the C. sumatrensis E. Walker and H. radicata L. were expected to be increased. The distribution area and range of T. peduncularis (Trevir.) Benth. Ex Hemsl. and L. amplexicalue L. were rapidly decreased. Non-climatic factors such as land cover and altitude were the most important environmental variable for T. officinale Weber, C. bursa-pastoris(L.) L.W.Medicus, V. persica Poir., T. peduncularis (Trevir.) Benth. Ex Hemsl., and L. amplexicalue L.. Climatic factors were the most important environmental variable for C. sumatrensis E. Walker and H. radicata L.. It is expected that the future potential distribution of 7 indicator plants response to climate change will be used to monitor and to establish the management plan.

• 한국노년학
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• v.37 no.1
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• pp.15-32
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• 2017

The current study aims to identify the heterogeneous changes of functional disabilities in old age rather than to identify an average longitudinal pattern and to explore the effect of health status and social status as risk factors in functional disability trajectories. The sample consisted of a representative sample of community dwellers aged 65 and older from the Korean Longitudinal Study of Ageing (2006 - 2012) was the focus of the study. Latent Class Growth Analysis was used to identify the functional disability trajectory groups. Variables regarding health status and social status changes by class were identified using multinomial logistic regression. The results showed various change patterns in functional disability, which include independent (78%), stable high (4.4%), steeply increasing (7.1%), slightly increasing (5.5%), and moderate to low (4.7%). Aggravation in depressive symptoms and cognitive functions as well as decline in social participations and social engagements were significant predictors of membership in increasing group of functional disability. The findings provide important initial empirical information to target clinical practice and have implications in the importance of conducting research on groups with different characteristics.

• Current Research on Agriculture and Life Sciences
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• v.32 no.4
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• pp.225-230
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• 2014

This study investigates the effect of organic certification of apples on consumer preference in China as a way to support the expanded export of Korean apples to China. A choice experiment was designed to analyze the apple consumption in China. A total of 298 Chinese consumers answered the survey, and multinomial logit models were used to analyze the results. Organic certification was identified as an important determinant of consumer preference for apples in China, affecting both the evaluation and choice of country of origin. The results also indicated that Korean organic certification significantly increased the probability of Chinese consumers choosing Korean apples. Thus, organic certification by the Korean government should be strengthened to promote apple exports to China, plus the results of this study may provide useful information to promote agricultural product exports and improve the organic certification system.