• Land and Housing Review
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• v.4 no.3
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• pp.259-270
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• 2013

This paper defined the concept of unsold land and diagnosed the cause of unsold land of LH business site. The results are showing as follows. First, unsold land is defined as land could not be sold until the completion of the project, and plan to sell the unsold land can be changed partially. Second, the status of unsold land in the 226 project sites were analyzed. $146km^2$ area corresponding to 74.8% of the total capital area($195km^2$) are unsold. By purpose, co-residential($38km^2$), industry($21km^2$), exclusive residential($16.4km^2$), commercial business($12.5km^2$), education($10.2km^2$) was larger in order. Third, value enhancement target project sites were selected and its symptoms and the cause of unsold land were analyzed. For the project site over average unsold rate, 6 sites located in province and 2 sites located in capital region were selected through collecting the practitioners and expert opinion. These 8 sites are characterized that sale of land for medium and large co-residential, urban support facilities, block-shaped house and attached house was inactive. Also, these sites commonly experienced economic fluctuations, changes in market demand, supply and demand mismatch, inflexible planning standards.

• Journal of Life Science
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• v.21 no.2
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• pp.328-333
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• 2011

Melatonin has been known as an animal hormone. However, melatonin exists in diverse organisms including higher plants. The biosynthesis and physiological roles for melatonin in plants is still largely unknown, although both dicot and monocot plants have melatonin and some medicinal plants even contain large amounts of melatonin. In this study we detected melatonin in diverse Viola plants, in which melatonin had not been examined so far, by reverse phase HPLC analysis, demonstrating the wide existence of melatonin in the genus of Viola. We then fed tryptophan (Trp) and tryptamine (TAM) to the incubation medium for Viola leaf sections to test their effects on melatonin formation. Trp is also the hypothesized starting material of melatonin in plants, and TAM is the following intermediate produced by the decarboxylation of Trp. Trp feeding did not affect the contents of melatonin. In contrast, TAM feeding clearly increased the level of melatonin in Viola leaves. Because TAM is derived from Trp, we concluded that the Trp-TAM pathway exists in Viola plants as well. Ineffectiveness of Trp feeding to the change of melatonin contents supports the hypothesis that the decarboxylation step from Trp to TAM is the rate-limiting step in plant melatonin biosynthesis.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.325-330
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• 2004

Several kinds of low voltage cables have been used in nuclear power plants for the supply of electric power, supervision, and the propagation of control signals. These low voltage tables must be inspected for safe and stable operation of nuclear power plants. In particular, the degradation diagnosis to estimate the integrity of low voltage rabies has recently been emphasized according to the long use of nuclear power plants. In order to evaluate their degradation, the surrounding temperature, hardness of insulation material, elongation at breaking point (EAB), etc. have been used. However, the measurement of temperature or hardness is not useful because of the absence of quantitative criteria; the inspection of a sample requires turning off of the power plant power; and, the electrical inspection method is not sufficiently sensitive from the initial through the middle stage of degradation. In this research, based on the theory that the ultrasonic velocity changes with relation to the degradation of the material, we measured the ultrasonic velocity as low voltage cables were degraded. To this end, an ultrasonic degradation diagnosis device was developed and used to measure the ultrasonic velocity with the clothing on the cable, and it was confirmed that the ultrasonic velocity changes according to the degradation of low voltage cables. The low voltage cables used in nuclear power plants were degraded at an accelerated rate, and EAB was measured in a tensile test conducted after the measurement of ultrasonic velocity. With the increasing degradation degree, the ultrasonic velocity decreased, whose potential as a useful parameter for the quantitative degradation evaluation was thus confirmed.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.115-124
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• 1999

This study was conducted to investigate the effects of fertigation level such as 50%, 75% and 100% N of standard amount of chemical fertilizer,m and fertigation interval such as every irrigation, intervals of 1 and 2 weeks of piggery waste water(PWW) on the growth, yield of red pepper plant and the chemical properties of soil used. In early stage, growth of red pepper plant fertigated with PWW and that of red pepper plant applicated standard chemical fertilezer was the same, while it were increased as increasing application amounts of PWW, and later growth and total yield of red pepper plant were much more at 75% N fertigation of PWW. Inorganic content such as nitrogen, phosphate and potassium and chlorophyll content of red pepper leaves were increased as increasing fergigation amount of PWW. 50% fertigation level showed the lowest rate of fruit setting of red peper plant. For soil chemical properties, pH was slightly decreased, but available $P_2O_5$, and exchangeable K content were increased as increasing fertigation amount of PWW. Because there was not statistically significant difference in the growth, the yield of red pepper and chemical properties of soil used according to various fertigation intervals, and no need to artificially supply PWW, therefore fertigation by simple automatic system with tensiometer was thought to be better.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.339-348
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• 2012

The purpose of this study is to predict the economic size of foods-for-elderly market, which will be valuable information for establishing related policy and backup system. After setting the scope of related industry, detailed information for current market situation was investigated and a systematic forecast for market changes in the future was performed. Economic growth, changes in consumer expenditure and economic status of the elderly, current subscription of medical insurance and saving for pension were reflected. In addition, a survey toward related firms was completed and changes in aged population and incidence of chronic disease in the elderly were taken into account. Results show that the annual growth rate of the market was predicted to be the minimum 4.54% through the maximum 8.32% from 2010 to 2025 and its market size was forecasted to be the minimum 7,073 ten million won through the maximum 10,976 ten million won. It is expected that the market of foods-for-elderly will grow rapidly with development of foods technology and fast increase of aged population. Especially, growth of health functional foods and foods for special dietary uses for elderly will be distinguished. However, it seems that related firms are on the hedge, watching current trend of the related industry. This may results in insufficient supply against the demand. Therefore, policy for foods-for-elderly should be introduced and systematically administered, including R&D support, standardization and authentication for foods-for-elderly, construction of related database system.

• Korean Journal of Social Welfare Studies
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• v.49 no.2
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• pp.93-124
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• 2018

Using the Korean Survey of Household Finances and Living Conditions panel data from 2012~2016, this study analyzed youth (19~34 years) poverty and employment and examined the factors that affect employment status. The analysis revealed an increase in the proportion of young people who are students or jobless; the economic conditions of the young people varied by factors such as marital status, education, job status, and loans; and the government public transfer policy had little impact on reducing the relative poverty rate of the youth. We also examined the factors affecting the youth's employment status and the risk of being employed in low-paid jobs, using multi-logit and logit regression model respectively. Considering employment status, the older and more educated the youth were, the less frequently they were employed in temporary or daily jobs instead of regular ones, but there was no difference between genders in terms of having temporary or daily jobs. A logit analysis on the determinants of low-paid jobs demonstrated that women, the less educated, spouses or children of the household, and temporary or daily workers have a greater probability of working at low-paid jobs. As women became older, their risk of having low-paid jobs increased, which demonstrated the phenomenon of "lock-in" at low-paid jobs. Temporary or daily workers of all age groups faced a higher risk of lowpaid employment, which stood out for the youth. Based on these results, we suggest that government employment and welfare policies should consider individual characteristics of the youth and their life cycle, along with efforts to supply decent jobs, continuously and stably.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.22-29
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• 2015

The objectives of this study were to monitor the changes in soil solution nutrients and to evaluate their effect on rice uptake and yield. The changes of chemical characteristics of paddy soil solution were examined from the 58th fertilization experiment in which the continuous rice cropping experiment started in 1954 at the National Academy of Agricultural Science. The treatments were no fertilization (No fert.), inorganic fertilization (NPK), inorganic fertilizer plus rice straw compost (NPKC) and inorganic fertilizer plus silicate and lime fertilizer as a soil amendment (NPKCLS). The fertilizers were added at rates of standard fertilizer application rate in which nitrogen (N), phosphate ($P_2O_5$), potassium ($K_2O$), and sililcate ($SiO_2$) were applied at rates of $75{\sim}150kg\;ha^{-1}$, $70{\sim}86kg\;ha^{-1}$, $75{\sim}86kg\;ha^{-1}$, and $7.5Mg\;ha^{-1}$ respectively and lime was applied to neutralize soil acidity until 6.5. Average Electrical Conductivity (EC) of soil solution in NPKCLS and NPKC ranged from 1.16 to $2.00dS\;m^{-1}$. The $NH{_4}^+$ and $K^+$ levels in NPKCLS and NPKC were higher than that of the other treatments, due to high supply power of rice straw compost. The content of $H_3SiO{_4}^-$ was higher in NPKCLS because of silicate application. The dominant ions in soil solution were $Ca^{2+}$, $Mg^{2+}$ and $Na^+$ among cations and $HCO{_3}^-$, $SO{_4}^{2-}$, and $Cl^-$ among anions in all treatments. The continuous application of inorganic fertilizers plus rice straw compost (NPKC) and silicate fertilizer (NPKCLS) led to the changes of various chemical composition in soil solutions. Also, they had a significant impact on the improvement of rice inorganic uptake and grain yield. Especially, inorganic uptake by rice in NPKC and NPKCLS significantly increased than those in NPK plot; 14~46% for T-N, 32~36% for P, 43~57% for K, and 45~77% for Si. Therefore, the combined application of inorganic fertilizers with organic compost as a soil amendment is considered as the best fertilization practice in the continuous rice cropping for the improvement of crop productivity and soil fertility.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.683-690
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• 2021

The ventilation system of the engine room of a ship is generally installed to supply the combustion air necessary for the internal combustion engine and to remove the heat source generated in the engine room, and it must satisfy the international standard (ISO 8861) for the design conditions and calculation standards for the ventilation of the ship engine room. The response delay of the ventilation system including the fire detector is affected by the airflow formed inside the area and the location of the fire detector. In this study, to improve the initial fire detection response speed of a fire detector installed on a fishing vessel and to maintain the sensitivity of the installed detector, the smoke behavior was simulated using the air flow field inside the engine room, the amount of combustion air in the internal combustion engine, and the internal pressure of the engine room as variables. Analysis of the simulation results showed that reducing the flow rate in the air flow field and increasing the vortex by reducing the internal pressure of the engine room and installing a smoke curtain would accelerate the rise of the ceiling of the smoke component and improve the smoke detector response speed and ventilation system.

• Journal of Environmental Health Sciences
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• v.47 no.5
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• pp.410-424
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• 2021

Background: Subway stations have the characteristics of being located underground and are a representative public-use facility used by an unspecified number of people. As concerns about indoor air quality (IAQ) increase, various management measures are being implemented. However, there are few systematic studies and cases of long-term continuous measurement of underground station air quality. Objectives: The purpose of this study is to analyze changes and factors influencing IAQ in subway stations through real-time continuous long-term measurement using IoT-based IAQ sensing equipment, and to evaluate the IAQ improvement effect of a bio-filter system. Methods: The IAQ of a subway station in Seoul was measured using IoT-based sensing equipment. A bio-filter system was installed after collecting the background concentrations for about five months. Based on the data collected over about 21 months, changes in indoor air quality and influencing factors were analyzed and the reduction effect of the bio-filter system was evaluated. Results: As a result of the analysis, PM₁₀, PM_2.5, and CO₂ increased during rush hour according to the change in the number of passengers, and PM₁₀ and PM_2.5 concentrations were high when a PM warning/watch was issued. There was an effect of improving IAQ with the installation of the bio-filter system. The reduction rate of a new-bio-filter system with improved efficiency was higher than that of the existing bio-filter system. Factors affecting PM_2.5 in the subway station were the outdoor PM_2.5, platform PM_2.5, and the number of passengers. Conclusions: The IAQ in a subway station is affected by passengers, ventilation through the air supply and exhaust, and the spread of particulate matter generated by train operation. Based on these results, it is expected that IAQ can be efficiently improved if a bio-filter system with improved efficiency is developed in consideration of the factors affecting IAQ and proper placement.

• Journal of the Korea Institute of Building Construction
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• v.21 no.2
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• pp.129-139
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• 2021

Recent rise in the supply rate of new public apartment houses leads to an increasement in disputes regarding the construction quality of the apartments between the residents and the construction companies. According to the dispute cases filed for claiming the collective defect repair fees, inter-layer concrete joints turned out to be the most frequently disputed item. For this reason, this study selects the inter-layer concrete joints to further analyze the primary causes and details of each dispute case. From the results of this study, three primary causes of the disputes are found, which are 1) the absence of standard specifications for construction quality control and management after construction; 2) the absence of established standards for repair when construction defects are found; and 3) the fact that the court grants generous compensation for disputes concerning the apartment houses. In order to prevent construction defects in inter-layer concrete joints, this study provides three suggestions including 1) the current standard specifications for inter-layer concrete joints should be further specified by the Ministry of Land, Infrastructure and Transport; 2) a construction defect should be judged according to the compliance to the standard specifications; and 3) a clear and institutional protocol needs to be established for defect repair in cases that new public apartment houses have been judged to have defects.