• Journal of Wetlands Research
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• v.21 no.4
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• pp.384-391
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• 2019

Nutrients in stormwater runoff have raised concerns regarding water quality degradation in the recent years. Low impact development (LID) technologies are types of nature-based solutions developed to address water quality problems and restore the predevelopment hydrology of a catchment area. Two LID facilities, infiltration trench (IT) and infiltration planter (IP), are known for their high removal rate of nutrients through sedimentation and vegetation. Long-term monitoring was conducted to assess the performance and cite the advantages and disadvantages of utilizing the facilities in nutrient removal. Since a strong ionic bond exists between phosphorus compounds and sediments, reduction of total phosphorus (TP) (more than 76%), in both facilities was associated to the removal of total suspended solids (TSS) (more than 84%). The efficiency of nitrogen in IP is 28% higher than IT. Effective nitrification occurred in IT and particulate forms of nitrogen were removed through sedimentation and media filters. Decrease in ammonium- nitrogen (NH₄-N) and nitrite-nitrogen (NO₂-N), and increase in nitrate-nitrogen (NO₃-N) fraction forms indicated that effective nitrification and denitrification occurred in IP. Hydrologic factors such as rainfall depth and rainfall intensity affected nutrient treatment capabilities of urban stormwater LID facilities The greatest monitored rainfall intensity of 11 mm/hr for IT yielded to 34% and 55% removal efficiencies for TN and TP, respectively, whereas, low rainfall intensities below 5 mm resulted to 100 % removal efficiency. The greatest monitored rainfall intensity for IP was 27 mm/hr, which still resulted to high removal efficiencies of 98% and 97% for TN and TP, respectively. Water quality assessment showed that both facilities were effective in reducing the amount of nutrients; however, IP was found to be more efficient than IT due to its additional provisions for plant uptake and larger storage volume.

• KDI Journal of Economic Policy
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• v.12 no.2
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• pp.135-149
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• 1990

Housing owners in Korea have a variety of tax advantages such as income tax exemption for the imputed rent of owner-occupied housing, exemption from the capital gains tax and deduction of the estate tax for one-house households. These tax reliefs for housing owners not only conflict with the principle of horizontal and vertical equity, but also lead to resource misallocation by distorting the housing market, and thus bring about regressive distribution effects. Particularly in the case of Korea with its imperfect capital market, these measures exacerbate the inter-class inequality of housing ownership as well as inequalities in wealth, by causing the affluent to demand needlessly large housing, while the poor and young experience difficulties in purchasing residential properties. Therefore, the Korean tax system must be altered as follows in order to disadvantage owner-occupiers, especially those owners of luxury housing. These alterations will promote housing-ownership, tax burden equity, efficiency of resource allocation, as well as the desirable distribution of income. First, income tax deductions for the rent payments of tenants are recommended. Ideally, the way of recovering the fiscal equivalence between the owner-occupiers and tenants is to levy an income tax on the former's imputed rents, and if necessary to give them tax credits. This, however, would be very difficult from a practical viewpoint, because the general public may perceive the concept of "imputed rent" as cumbersome. Computing the imputed rent also entails administrative costs, rendering quite reasonable, the continued exemption of imputed rent from taxation with the simultaneous deduction in the income tax for tenants. This would further enhance the administrative efficiency of income tax collection by easing assessment of the landlord's income. Second, a capital gains tax should be levied on the one-house household, except with the postponement of payments in the case that the seller purchases higher priced property. Exemption of the capital gains tax for the one-house household favors those who have more expensive housing, providing an incentive to the rich to hold even larger residences, and to the constructors to build more luxurious housing to meet the demand. So it is not desirable to sustain the current one-house household exemption while merely supplementing it with fastidious measures. Rather, the rule must be abolished completely with the concurrent reform of the deduction system and lowering of the tax rate, measures which the author believes will help optimize the capital gains tax incidence. Finally, discontinuation of the housing exemption for the heir is suggested. Consequent increases in the tax burden of the middle class could be mitigated by a reduction in the rate. This applies to the following specific exemptions as well, namely, for farm lands, meadows, woods, business fields-to foster horizontal equity, while denying speculation on land that leads to a loss in allocative efficiency. Moreover, imperfections in the Korean capital market have disallowed the provision of long term credit for housing seekers. Remedying these problems is essential to the promotion of greater housing ownership by the low and middle income classes. It is also certain that a government subsidy be focused on the poorest of the poor who cannot afford even to think of owning a housing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.47-56
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• 2020

In this study, three levels of W/B(Water to Binder) ratio (0.37, 0.42, 0.47) and substitution ratio of GGBFS (Ground Granulated Blast Furnace Slag) rate (0 %, 30 %, 50 %) were considered to perform RCPT (Rapid Chloride Diffusion Test) at the 1,095 aged day. Accelerated chloride diffusion coefficient and passed charge of each concrete mixture were assessed according to Tang's method and ASTM C 1202, and improving behaviors of durability performance with increasing aged days are analyzed based on the test results of previous aged days from the preceding study. As the age of concrete increases, the passed charge and diffusion coefficient have been significantly reduced, and especially the concrete specimens containing GGBFS showed a significantly more reduction than OPC(Ordinary Portland Cement) concrete specimen by latent hydraulic activity. In the case of OPC concrete's results of passed charge, at the 1,095 days, two of them were still in the "Moderate" class. So, if only OPC is used as the binder of concrete, the resistance performance for chloride attack is weak. In this study, the time-parameters (m) were derived based on the results of the accelerated chloride diffusion coefficient, and the deterministic and probabilistic analysis for service life were performed by assuming the design variable as a probability function. For probabilistic service life analysis, durability failure probabilities were calculated using Monte Carlo Simulation (MCS) to evaluate service life. The service life of probabilistic method were lower than that of deterministic method, since the target value of PDF (Probability of Durability Failure) was set very low at 10 %. If the target value of PDF suitable for the purpose of using structure can be set and proper variability can be considered for each design variable, it is believed that more economical durability design can be made.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.467-473
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• 2007

Although the dominant land use at the Imha-dam watershed is forest areas, soil erosion has been increasing because of intensive agricultural activities performed at the fields located along the stream for easy-access to water supply and relatively favorable topography. In addition, steep topography at the Imha-dam watershed is also contributing increased soil erosion and sediment loads. At the Imha-dam watershed, outflow has increased sharply by the typhoons Rusa and Maemi in 2002, 2003 respectively. In this study, the Soil and Water Assessment Tool (SWAT) model was evaluated for simulation of flow and sediment behaviors with long-term temporal and spatial conditions. The precipitation data from eight precipitation observatories, located at Ilwol, Subi and etc., were used. There was no significant difference in monthly rainfall for 8 locations. However, there was slight differences in rainfall amounts and patterns in 2003 and 2004. The topographical map at 1:5000 scale from the National Geographic Information Institute was used to define watershed boundaries, the detailed soil map at 1:25,000 scale from the National Institute of Highland Agriculture and the land cover data from the Korea Institute of Water and Environment were used to simulate the hydrologic response and soil erosion and sediment behaviors. To evaluate hydrologic component of the SWAT model, calibration was performed for the period from Jan. 2002 to Dec. 2003, and validation for Jan. 2004 to Apr. 2005. The $R^2$ value and El value were 0.93 and 0.90 respectively for calibration period, and the $R^2$ value and El value for validation were 0.73 and 0.68 respectively. The $R^2$ value and El value of sediment yield data with the calibrated parameters was 0.89 and 0.84 respectively. The comparisons with the measured data showed that the SWAT model is applicable to simulate hydrology and sediment behaviors at Imha dam watershed. With proper representation of the Best Management Practices (BM Ps) in the SWAT model, the SWAT can be used for pre-evaluation of the cost-effective and sustainable soil erosion BMPs to solve sediment issues at the Imha-dam watershed. In Korea, the Universal Soil Loss Equation (USLE) has been used to estimate the soil loss for over 30 years. However, there are limitations in the field scale mdel, USLE when applied for watershed. Also, the soil loss changes temporarily and spatially, for example, the Imha-dam watershed. Thus, the SW AT model, capable of simulating hydrologic and soil erosion/sediment behaviors temporarily and spatially at watershed scale, should be used to solve the muddy water issues at the Imha-dam watershed to establish more effective muddy water reduction countermeasure.

• Journal of Korea Port Economic Association
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• v.30 no.1
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• pp.175-194
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• 2014

Because the thawing of the Arctic ocean is slowly accelerating due to global warming, recently exploring resources in Arctic ocean and transporting resources by using the North Pole route have been getting spotlight. Since the original route transported by the Suez Canal from Korea to Europe could be shorten about 8,000km in distance(decreased about 38% compared to the original route), which means shortening about 10 voyage dates, it is expected to bring huge logistics cost reduction. Once the North Pole route is commercialized successfully, it would be one of the most important variables that affects future of Busan port and guides for economic development of Busan. Therefore, the purpose of this study is to analyze Busan port and the economic growth of Busan area by researching promising industry, based on the effect of freight transporting by the Northern sea route on the economy of Busan. For this study, questionnaire surveys and interviews were conducted for 64 people of experts in the shipping and port industry, relevant government, and academics. The survey finding shows that port logistics industry is a promising business in Busan in terms of its growth and competitiveness. It is necessary to develop feeder network facilities that prepare for commercialization of the Northern sea route as a short and medium term plan and provide professional manpower training in polar regions. Ship supply business would also play an important role. It is identified that revitalization of shipbuilding and ocean plant industry should be done in terms of Arctic business. With regard to the fishery industry it is found that modernization of fishery ship and development of fishery equipment used in polar areas should be carried out.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.109-121
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• 2021

As the global COVID-19 pandemic is prolonged, the Corona Blue phenomenon, combined with COVID-19 and blue, is intensifying. The purpose of this study is to analyze the current trend of Corona Blue in consideration of the possibility of increasing mental illness and the need for countermeasures, especially after COVID-19. This study tried to find out the relationship between stress and leisure activities before and after COVID-19 by using Corona Blue news article analysis through the topic modeling method, and questionnaire find out the help of stress and leisure activities. This study was compared and analyzed using two research methods. First, a total of 363 news articles were analyzed through topic modeling based on newspaper articles from January 2020, when COVID- 19 was upgraded to the "border" stage, until September, where the social distancing stage was strengthened to stage 2.5 in Korea. As a result of the study, a total of 28 topics were extracted, and similar topics were grouped into 7 groups: mental-demic, generational spread, causes of depression acceleration, increased fatigue, attitude to coping with long-term wars, changes in consumption, and efforts to overcome depression. Second, the SPSS statistical program was used to analyze the level of stress change according to leisure activities before/after COVID-19 and the main help according to leisure activities. As a result of the study, it was confirmed that the average difference in stress reduction according to participation in leisure activities before COVID-19 was larger than after COVID-19. Also, leisure activities were found to be effective in stress relief even after COVID-19. In addition, if the main help from leisure activities before COVID-19 was the meaning of relaxation and recharging through physical and social activities. After COVID-19, psychological roles such as mood swings through nature, outdoor activities, or intellectual activities were found to play a large part. As such, in this study, it was confirmed that understanding the current status of Corona Blue and coping with leisure in extreme stress situations has a positive effect. It is expected that this research can serve as a basis for preparing realistic and desirable leisure policies and countermeasures to overcome Corona Blue.

• Journal of agricultural medicine and community health
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• v.44 no.1
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• pp.11-27
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• 2019

Dementia is major epidemic disease of the 21st century in the world. Dementia is one of the major issues in public health globally. Also in Korea, the estimated prevalence of dementia was 8.7%(0.47 million) in 2010, the number will reach the 1 million mark in 2024, it will become a 15.1%(2.71 million) by 2050. Among Koreans aged 65 or older, 725,000 are estimated to be suffering from dementia in 2017. Against dementia, Korea developed three National Dementia Plans in 2008, 2012, and 2016. The 1st plan was came into effect in 2008 and focused on prevention, early diagnostic, development and coordination of infrastructures and management, and improving awareness. The 2nd plan was launched in 2012, addressed the same priorities but had a stronger focus on supporting family members. In 2012 the Dementia Management Act established a statutory basis for organization of the National Dementia Plans. Under the Dementia Management Act, the government is required to produce a comprehensive plan for dementia every 5 years. The Act also orders that the government should register the dementia patients and collect statistics on epidemiology and the management of the dementia conditions. The Dementia Management Act of Korea required the operation of the National Institute of Dementia and Metropolitan/Provincial Dementia Centers to make and carry out dementia management plans throughout the nation. The Act also mandate to establish Dementia Counselling Centers in every public health center and the National Dementia Helpline. The 3rd National Dementia Plan of 2016 aims to build a dementia friendly community to ensure people with dementia and their carer live well. This plan focus on community-based prevention and management of dementia, convenient and safe diagnosis, treatment, and care for people with dementia, the reduction of the care burden for family care-givers of people with dementia, and support for dementia research through research, statistics and technology. In 2017, Moon's government will introduce the "National Dementia Responsibility System," which guarantees most of the burden caused by dementia. This plan include that the introduction of a ceiling on self-pay for dementia diseases, expansion of the application of dementia care standards through alleviating the support criteria for long-term care insurance for mild dementia, expansion of dementia support centers, expansion of national and public dementia care facilities. In the meantime, Korea has accomplished many accomplishments by establishing many measures related to dementia and promoting related projects in a short time, but there are still many challenges.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Journal of the Korean Orthopaedic Association
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• v.56 no.3
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• pp.208-214
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• 2021

Purpose: Verifying a reliable predictor of the progression of vertebral deformity in patients with acute osteoporotic fractures of the lumbar spine may be useful. A qualitative analysis of the muscle near the spine was performed using magnetic resonance imaging (MRI), and its correlation with a spinal deformity was determined under the hypothesis that the causes of the kyphotic deformity are associated with muscle reduction in the multifidus and erector spinae. Materials and Methods: The study was performed in a retrospective manner using the electronic medical records of patients who presented to the author's institution between January 2007 and March 2018, and were diagnosed with an acute lumbar fracture. The fat infiltration rates of the multifidus and erector spinae were measured using MRI taken at the time of injury, and the mean value was defined as the total fat infiltration rate (TFI). Based on lateral radiographs of the lumbar spine at the one-year follow-up, the loss of height of the vertebral body, the kyphotic angle and the wedge angle were measured. The statistical significance was confirmed by calculating the Pearson correlation coefficient. Results: One hundred twenty-nine patients, of which 30 were male and 99 were female, were examined. The mean age was 71.28 years. The mean T-score was -3.53±0.79 g/cm², and the mean fat infiltration was 15.20%±11.99%. TFI was positively correlated with age (R=0.373, p<0.001), compression rate (R=0.369, p<0.001), and Cobb's angle (R=0.386, p<0.001) after a one year follow-up, but negatively correlated with the BMD score (R=-0.252, p=0.004). As the fracture progressed to the lower lumbar level, the compression rate (R=-0191, p=0.030) and wedge angle (R=-0.428, p<0.001) at the time of injury tended to decrease. Conclusion: In patients with osteoporotic vertebral fractures, the fat infiltration rate may be an important predictor of conservative treatment. The prognosis of patients with a high-fat infiltration rate should be explained during patient education, and the patients must be monitored closely through short-term outpatient follow-up.

• Journal of Korean Society of Disaster and Security
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• v.14 no.4
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• pp.69-80
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• 2021

This study tried to suggest improvement measures by discovering problems or matters requiring improvement among the annual regional safety evaluation systems. Briefly introducing the structure and contents of the study, which is the introduction, describes the regional safety evaluation method newly applied by the Ministry of Public Administration and Security in 2020. Utilization plans were also introduced according to the local safety level that was finally evaluated by the local government. In this paper, various views of previous researchers related to regional safety are summarized and described. In addition, problems were drawn in the composition of the index of local safety, the method of calculating the index, and the application of the current index. Next, the problems of specific regional safety evaluation indicators were analyzed and solutions were presented. First, "Number of semi-basement households" is replaced with "Number of households receiving basic livelihood" of 「Social Vulnerability Index」 in the field of disaster risk factors is replaced with "the number of households receiving basic livelihood". In addition, the "Vinyl House Area" is evaluated by replacing "the number of households living in a Vinyl House, the number of container households, and the number of households in Jjok-bang villages" with data. Second, in the management and evaluation of habitual drought disaster areas, local governments with a water supply rate of 95% or higher in Counties, Cities, and Districts are treated as "missing". This is because drought disasters rarely occur in the metropolitan area and local governments that have undergone urbanization. Third, the activities of safety sheriffs, safety monitor volunteers, and disaster safety silver monitoring groups along with the local autonomous prevention foundation are added to the evaluation of the evaluation index of 「Regional Autonomous Prevention Foundation Activation」 in the field of response to disaster prevention measures. However, since the name of the local autonomous disaster prevention organization may be different for each local government, if it is an autonomous disaster prevention organization organized and active for disaster prevention, it would be appropriate to evaluate the results by summing up all of its activities. Fourth, among the Scorecard evaluation items, which is a safe city evaluation tool used by the United Nations Office for Disaster Risk Reduction(UNDRR), the item "preservation of natural buffers to strengthen the protection functions provided by natural ecosystems" is borrowed, which is closely related to natural disasters. The Scorecard evaluation is an assessment index that focuses on improving the disaster resilience of local governments while carrying out the campaign "Creating cities resilient to climate crises and disasters" emphasized by UNDRR. Finally, the names of "regional safety level" and "local safety index" are similar, so the term of local safety level is changed to "natural disaster safety level" or "natural calamity safety level". This is because only the general public can distinguish the local safety level from the local safety index.