• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.473-478
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• 2011

A wide diversity of liquid fertilizers and composts produced from the livestock manure in Korea is commonly applied to agricultural lands as an alternative of chemical fertilizers. However, their effects on the crop production and environmental impacts are still vague. The current study was conducted to understand the effects of the pig manure-based liquid fertilizer on the growth of Zea mays L. and soil properties. Four different liquid fertilizers were treated to each cultivated upland plot located in Gyeong-gi province, Korea while no fertilizer (control A) and a chemical fertilizer (control B) were treated to separate plots for comparison. The liquid fertilizer treatment did not make a significant difference in the fresh weight of Zea mays L. compared to the controls. This is probably due to the nutrient residues carried over from the last year fertilization. Electric conductivity (EC) and organic matter contents in soils were increased right after the liquid fertilizer treatments compared to the controls. However, soil pH was maintained as the same as the level of control A. A long-term effect of the continuous treatment of the manure based liquid fertilizer will be carried out in the successive study.

• Atmosphere
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• v.31 no.4
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• pp.361-376
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• 2021

"Gangwon Yeongdong Wind Experiments (G-WEX) Pilot Study: Downslope windstorms in the Taebaek Mountains, South Korea" is promoted based on joint organization by Gangwon Regional Office of Meteorology and National Institute of Meteorological Research and participation by 12 institutions to understand the mechanism in development of Yeongdong wind phenomena. The special observation (G-WEX) involved total of 5 intensive observations in March 2020 and April 2020. To collect the data necessary for the research on Yeongdong wind phenomena, (1) high-resolution surface observation network was used to examine surface wind and (2) atmospheric soundings were observed by using Rawinsonde, Wind profiler, Wind Lidar, and Drone. This study covers the detailed information on the special observational experiments for downslope windstorms in the leeward of the Taebaek Mountains, named as the Yeongdong wind, including the observational strategies, experimental designs, and pilot studies during the Intensified Observing Period (IOPs). According to 2020 G-WEX observation results, downslope windstorms were observed in 2~3 km of upper atmosphere when the strong winds happened around the top of the mountain near Daegwallyeong. Also, dry adiabatic expansion related to downslope windstorms caused temperature rise and led to formation of an inversion layer in altitude below 2.5 km. Bands of strong wind were located right under the altitude where downslope windstorms are observed with temporal rise of the temperature. As these are preliminary observation results, there needs to be continuous related researches and high-resolution weather observation.

• Korean Journal of Construction Engineering and Management
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• v.22 no.6
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• pp.87-95
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• 2021

This study analyzed economic feasibility using the real options theory of the eco-environment area project in Saemangeum. I defined the main factors affecting project sales during the 30 years operation period. The real option-based analysis is proposed through the managerial flexibility by estimating the volatility of project sales using scenarios analysis method. The number of visitors, admission fee, leisure program fee, and O&M costs required for economic analysis of eco-environment park were analyzed by reviewing cases of similar eco-environment parks in Korea. The option value is calculated by assuming that the developers have an option right that can be abandoned. B/C is less than 1 and NPV is negative, so it is impossible to proceed with the project using the traditional economic analysis. The project value difference between NPV (-46.6 billion Won) and option value (28.1 billion Won) increased by 74.7 billion Won. Through this study, decision-makers of public institutions and private developers who plan eco-environment area projects will be able to use the real option technique proposed in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.143-150
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• 2021

Roundabouts have been spreading out all over the world quickly with their attractions including capacity enhancement, safety increase and pollutant emission decrease. The history of Korean roundabout has already been 10 years. However, due to the accumulation of unclear right of way and insufficient data, the advantages of the roundabout are not fully utilized so far. Moreover, there are some differences in the capacity model of roundabouts compared to overseas capacity models. In addition, most research tend to concentrate in evaluation of roundabout performance using computer software. This paper, therefore, investigated overseas typical roundabout capacity models; empirical model and gap acceptance model, and then KHCM 2013 was compared to SIDRA model and USHCM 2010 model. It is expected that this paper will assist and guide practitioners in analyzing and estimating roundabout capacity more precise.

• International Journal of Oral Biology
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• v.44 no.3
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• pp.115-123
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• 2019

Among the environmental chemicals that may be able to disrupt the endocrine systems of animals and humans are polychlorinated biphenyls (PCBs), a chemical class of considerable concern. PCB consists of two six-carbon rings linked by a single carbon bond, and theoretically, 209 congeners can form, depending on the number of chlorines and their location on the biphenyl rings. Furthermore, 3,3',4,4',5-pentachlorobiphenyl (PCB126) exposure also increases nitric oxide production and nuclear factor kappa-light-chain-enhancer of activated B cells binding activity in chondrocytes, thus contributing as an initiator of chondrocyte apoptosis and resulting in thymic atrophy and immunosuppression. This study identified whether cardiac and immune abnormalities from PCB126 were caused by the Kv1.3 and Kv1.5 channels. PCB126 did not affect either the steady-state current or peak current of the Kv1.3 and Kv1.5 channels. However, PCB126 right-shifted the steady-state activation curves of human Kv1.3 channels. These results suggest that PCBs can affect the heart in a way that does not block voltage-dependent potassium channels including Kv1.3 and Kv1.5 directly.

• Convergence Security Journal
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• v.18 no.3
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• pp.95-103
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• 2018

The military's morale is a serious threat in terms of defense posture and protection of national security and the nation's right to survival, as it has led to losses in talented manpower, weakened fighting spirit, damaged troop confidence, and reduced work efficiency and morale. Under these circumstances, a stronger defense posture and maximum morale among the troops should be followed by a thorough diagnosis and results on the factors affecting the military's morale. Professional soldiers often travel to work because of the special nature of their jobs. Among the problems associated with these characteristics is child education. Frequent shifts of military sites are intended to be made based on the analysis of the overall state of the military service education system, such as moving frequently with family members or separating with the family due to issues related to children's education.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.1
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• pp.27-33
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• 2019

Objective: This study analyzed the status of the application of trade secrets in MSDSs according to size and type of industry. The contents of the MSDS non-public approval policy are summarized. We suggest proactive improvement requirements related to the operation of the MSDS non-public approval policy. Methods: To review this subject, we selected 153 manufacturers and six importers in such fields as organic chemical production. The trade secrets application status and ratio (%) of MSDSs by industry size and industry classification were investigated. Improvements toward a proactive system related to the operation of the MSDS non-public approval policy under the Occupational Safety and Health Act(OSHA) were summarized. Results and Conclusions: According to the results, the trade secret ratio in MSDSs by industry size was 33% in workplaces with less than 50 employees, 23.1% in workplaces with more than 50 but less than 100 workers, 73% in workplaces with more than 100 workers, and 83.4% in workplaces with 300 or more workers. For the trade secret writing rate for MSDSs by industry, the highest was MOCCP (Manufacture of ink, paint, coating and similar products) at 80.9%. MOC (Manufacture of other chemicals) was the lowest at 16.2%. We propose four proactive efforts to minimize the administrative burden of implementation of the MSDS non-public approval policy. The results of this study can be used as basic data for policy improvements to make more effective use of MSDS.

• Environmental and Resource Economics Review
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• v.28 no.1
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• pp.39-59
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• 2019

The Korean Demilitarized Zone (DMZ) has the great ecosystem as all the artificial activities in DMZ have been prohibited over half a century. The ecosystem should be conserved even after the reunification of Korea and hence the conservation plan should be established not after the reunification but before it. It requires a considerable budget to conserve DMZ, considering management of ecology resource, recovery, and research. The objective of this paper is to analyze a fund-raising measure for DMZ conservation, using economic incentives mechanism when multiple developers participate in the auction to get the right to develop North Korean regions, have private information about their sunk costs and pay a part of their profits for the fund. First, we analyze the real option model to decide the optimal investment time. Second, we construct the auction for bidders not to misrepresent their private information, based on Bayesian Nash equilibrium.

• Environmental and Resource Economics Review
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• v.27 no.4
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• pp.667-694
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• 2018

We analyze the learning-by-doing effects of the allowance pricing system on the Korea's emission trading scheme. The price of allowance (Korean Allowance Unit) is influenced differently by internal market factors and economic conditions variables in the first (January 2015 to June 2016 ) and the second commitment year(January 2016 to June 2017). The prices and transaction volumes of complementary credits (KCU and KOC) as well as economic conditions variables (such as call rate, exchange rate, stock price) are statistically significant only for the second commitment year. Thus, the learning-by-doing effect makes the market participation decision on K-ETS market more efficient in the second commitment year, adopting the previous experience and knowledge in the K-ETS market. The factors estimated significantly in both commitment periods include the institutional binary variable for requiring the submission of the emissions verification reports issued both on February and March.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.57-65
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• 2022

Gyeongsangnam-do has been operating Bravo-taxi, a Gyeongnam-type DRT using taxi vehicles, since 2017 to guarantee the right of mobility for residents who live in areas lacking public transportation. This research investigated and analyzed changes in users' awareness over two years from beginning of Bravo-taxi operation in Gyeongsangnam-do, which started operating Bravo-taxis in 2017, targeting sites lacking public transportation. Through this study, the positive effects of taxi-type DRT were confirmed, such as improving the mobility of residents in areas underprivileged by public transportation, reducing required time for trips, and increasing preference for Bravo-taxis compared to existing buses. On the other hand, problems with the current Bravo-taxi system were also identified. In some areas, it was found that there were not enough coupons for Bravo-taxis, or in the case of Bravo-taxis operating at fixed times, the user's desired time and operating time did not match, resulting in lower satisfaction. The results of this research are expected to be utilized as basic data for service continuity of taxi-type DRT in operation by other local governments.