• Journal of the Korean association of regional geographers
• /
• v.20 no.4
• /
• pp.393-408
• /
• 2014

In this study, the spatio-temporal characteristics of summer extreme precipitation events in the Republic of Korea are examined based on the daily precipitation data observed at approximately 360 sites of both Automatic Weather Station (AWS) and Automated Synoptic Observation System (ASOS) networks by the Korea Meteorological Administration for the recent decade(2002~2011). During the summer Changma period(late June~mid July), both the frequency of extreme precipitation events exceeding 80mm of daily precipitation and their decadal maximum values are greatest at most of weather stations. In contrast, during the Changma pause period (late July~early August), these patterns are observed only in the northern regions of Geyeonggi province and western Kangwon province as such patterns are detected around Mt. Sobaek and Mt. Halla as well as in the southern regions of Geyeonggi province and western Kangwon province during the late Changma period (mid August~early September) due to north-south oscillation of the Changma front. Investigation of their regional patterns confirms that not only migration of the Changma front but also topological components in response to the advection of moistures such as elevation and aspect of major mountain ridges are detrimental to spatio-temporal patterns of extreme precipitation events. These results indicate that each local administration needs differentiated strategies to mitigate the potential damages by extreme precipitation events due to the spatiotemporal heterogeneity of their frequency and intensity during each Changma period.

• Environmental Analysis Health and Toxicology
• /
• v.23 no.1
• /
• pp.53-62
• /
• 2008

In the present study, the concentration levels of polychlorinated biphenyls (or PCBs) in the environments in Korea are estimated based on some measured data in Korea, in comparison with the data from the other countries. Even though PCBs were banned as electrical fluids in 1970s in Korea, PCBs are still detected in the environment. PCBs levels in Korea are greatly lower than those in other countries, which are gradually decreased as well. However, the measured data are not sufficient in both numbers and quality, to estimate the average PCBs levels in Korea. The regulation limit on polychlorinated biphenyls (or PCBs) is 2mg/kg (ppm), which is too low compared to 50 ppm of many other countries including U.S. With this strict regulation, there are many problems expected, for example, in the analysis of PCBs in the transformers using in the field as well as the safe treatment of PCBs. The risk assessment on the PCBs in the environment is surely necessary prior to the change in the limit. Also the PCBs concentration monitoring in the environmental media (i.e. air, water, soil and sediment) and exposure assessment will be essential for the accurate risk assessment. If the PCB-waste guideline maintain as 2 ppm after 10 years, the excess cancer risk of PCBs exposure by ambient air, drinking water and soil was $10^{-8}$. But if the guideline mitigate as 50 ppm after 10 years, the cancer risk was increased by $10^{-7}$. The ecological risk quotient by regulation change was not exceed '1'.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.7
• /
• pp.461-468
• /
• 2014

Biochar is a carbon rich solid produced by the pyrolysis of biomass such as energy crops, forestry residues, and wood wastes. Biochar returned to soil is to mitigate climate change and the feedstock of wood wastes reduces fossil fuel consumption as well as disposal costs. This study was practiced to evaluate a biochar system by gasification in terms of global warming regarding the soil application of the produced biochar. Life cycle assessment methodology was used to analyze the environmental impacts of the system, and the functional unit was 1 tonne of wood wastes. The result shows that the biochar system by using wood wastes as feedstock produces 4.048E-01 $kgCO_2-eq$ from the pre-treatment process as chipping and drying, 4.579E-01 $kgCO_2-eq$ from the pyrolysis process, and 9.070E-02 $kgCO_2-eq$ from the spreading to agricultural land, therefore total 9.534E-01 $kgCO_2-eq$ are generated. About 252 kg of $CO_2$ is still stored in the produced biochar in soil after carbon offsetting of the system. Therefore, the net carbon of the system is -251 kg of $CO_2-eq$.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.58
• /
• pp.3-33
• /
• 2013

The purpose of this paper is to examine the problems in exercising buyer's right to claim damages for the breach of contract by the seller in international sales contract and to suggest reasonable counter-measures. The main contents are as follows: First, this author analyzed the principles of the seller's liability for damages in detail and examined the methods for the calculation of damages on the basis of Arts.74~77. As these articles are found to be insufficient in practical application, this author further examined the UNIDROIT Principles(2004) to confirm whether these Principles can fill the gaps of CISG or not, which turned out their gap-filling functions. Second, this author tried to find any expected problems when the buyer resorts to the right to claim damages in case of the seller's breach of contract including the estimation of damages, the burden of proof, causation, the proof of appropriateness for avoidance, the proof of buyer's obligation to mitigate the loss and so on. The reason is that these problems may cause a lot of difficulties in real business. As result, many buyers have given up their reasonable rights to claim damages so far. Finally, from the buyer's perspective, this author would like to suggest a liquidated damage clause(LD Clause) which gives the buyer to received a specified sum in case of seller's non-performance and/or a demand guarantee(or standby L/C) which guarantees buyer to secure unconditional payment independent of the underlying contract. For these purposes, the buyer should try to insert the LD Clause and/or Guarantee Clause in the contract when the buyer and the seller negotiate the sales contract. Also there are a lot of considerations and limitations in using the LD Clause and the Guarantee Clause in their real business, mainly dependent up bargain power between the seller and the buyer, for which this author promise to examine in detail in the future.

• The Journal of the Korea Contents Association
• /
• v.20 no.7
• /
• pp.404-416
• /
• 2020

Flooding is an unavoidable natural disaster for the city. Flood disasters seriously undermine the city's economy, safety, and sustained development. In the course of development and construction of waterfront space in the same city, the construction of basic disaster prevention facilities cannot be avoided completely even if huge amounts of capital are invested to reduce the economic damage of flooding. The cost of rebuilding the city after the disaster is much higher than the cost of building disaster prevention facilities. In recent years, the theory of elasticity in urban reconstruction and so on has been a subject of city problem solving, creating widespread discussion and attention in academia. In other words, how to transform the concept of elasticity into practice based on theoretical and empirical factors is a real problem facing urban disaster. Through theoretical literature on the waterfront (space) buffer zone of a city (flood-weak area) and the case study of the city's practice, this paper tries to clarify the element of 5R, the theory of elastomeric fire prevention, and present detailed measures accordingly. In addition, the following two problems are addressed while emphasizing the feasibility of implementing the urban waterfront (space) plan of the elastomeric element around the urban water buffer zone. First, the means of disaster prevention planning are used to mitigate conflicts between individual utility of urban waterfront and disaster prevention functions in waterfront buffer zones, and second, the waterfront buffer zone can respond to flood-causing problems in terms of disaster prevention as much as possible through the elastic disaster prevention plan.

• Journal of Intelligence and Information Systems
• /
• v.10 no.1
• /
• pp.109-123
• /
• 2004

Corporate financial distress and bankruptcy prediction is one of the major application areas of artificial neural networks (ANNs) in finance and management. ANNs have showed high prediction performance in this area, but sometimes are confronted with inconsistent and unpredictable performance for noisy data. In addition, it may not be possible to train ANN or the training task cannot be effectively carried out without data reduction when the amount of data is so large because training the large data set needs much processing time and additional costs of collecting data. Instance selection is one of popular methods for dimensionality reduction and is directly related to data reduction. Although some researchers have addressed the need for instance selection in instance-based learning algorithms, there is little research on instance selection for ANN. This study proposes a genetic algorithm (GA) approach to instance selection in ANN for bankruptcy prediction. In this study, we use ANN supported by the GA to optimize the connection weights between layers and select relevant instances. It is expected that the globally evolved weights mitigate the well-known limitations of gradient descent algorithm of backpropagation algorithm. In addition, genetically selected instances will shorten the learning time and enhance prediction performance. This study will compare the proposed model with other major data mining techniques. Experimental results show that the GA approach is a promising method for instance selection in ANN.

• Strategy21
• /
• s.45
• /
• pp.5-32
• /
• 2019

The paper introduces US Indo-Pacific Strategy and discusses its meanings and implications for international security and our strategy. It tries to look at the Indo-Pacific strategy(IPS) through the lenses of international political theories. The paper provides three important observations. First, the US Indo-Pacific strategy is a declaration of the national identity of the US as an Indo-Pacific nation. The paper argues that the IPS reflects the US leadership that would facilitate the formation of, so called, the Indo-Pacific community. In arguing these points, the paper notes that the IPS has rich elements of constructivist approaches including norms and national identity. Second, the paper observes that the IPS report serves as an effective deterrent strategy. The IPS does not call out China as an enemy. But, it tries to deter against a range of actors including China by warning that whoever violates the rules-based order in the region would have consequences. Third, the paper maintains that the IPS is an effort by the US to mitigate the risk of a great power war between the US (an established power) and China (a challenging power) because the IPS articulates the United States's willingness to work with China as long as it plays by the rules. There will be challenges to the US and other countries in the region including South Korea particularly because of economic interdependence. However, the paper argues that the IPS stands for an optimistic sign of the future security in the Indo-Pacific region because it is a manifestation of the US for its national will to defend the status quo characterized as Pax Americana which has been maintained since the end of the Second World War. It also argues that South Korea also can, and should make the most of this opportunity by enhancing our capacity in national defense.

• Journal of Korean Society for Atmospheric Environment
• /
• v.28 no.6
• /
• pp.697-705
• /
• 2012

Particulate matter (PM) data collected from the Urban Air Monitoring Network in Busan during the period from 2006 through 2010 were statistically examined and analyzed to estimate the probability of exceeding $PM_{2.5}$ 24 hour and annual standard to be implemented from January $1^{st}$, 2015. For Jangrimdong, Yeonsandong, Kijangeup, and Jwadong where simultaneous measurement of $PM_{10}$ and $PM_{2.5}$ was conducted, the probability of exceeding $PM_{2.5}$ standards was estimated using $PM_{2.5}$ data measured on site. For other areas where there were no measured $PM_{2.5}$ data available, the probability of exceeding $PM_{2.5}$ standards was statistically estimated using $PM_{10}$ measured on site and $PM_{2.5}/PM_{10}$ ratios obtained from the four stations where both $PM_{2.5}$ and $PM_{10}$ were monitored simultaneously. At Jangrimdong, Yeonsandong, Kijangeup, and Jwadong, mean value of annual 99 percentile of 24 hr average $PM_{2.5}$ for 5 years from 2006 through 2010 was 99.3, 74.5. 57.0, and $62.5{\mu}g/m^3$, respectively, and the probability of exceeding $PM_{2.5}$ 24 hr standard was estimated at 100%. For areas where there were no measured $PM_{2.5}$ data available, the estimated probability of exceeding $PM_{2.5}$ 24 hr standard was more than 0.82. Mean value of annual average $PM_{2.5}$ from 2008 through 2010 was 31.7 and $27.6{\mu}g/m^3$ for Jangrimdong and Yeonsandong, respectively, which exceeded $PM_{2.5}$ annual standard of $25{\mu}g/m^3$. Mean value of annual average $PM_{2.5}$ during the same period for Kijangeup and Jwadong was 19.2 and $20.7{\mu}g/m^3$, respectively, which satisfied $PM_{2.5}$ annual standard. For other areas where there were no measured $PM_{2.5}$ data available, the probability of exceeding $PM_{2.5}$ annual standard was more than 0.95 except Taejongdae and Kwangahndong. With $PM_{10}$ and $PM_{2.5}$ data measured at 17 Urban Air Monitoring Stations in Busan, the probability of exceeding $PM_{2.5}$ standards was estimated to be very high for almost all areas. This result indicates that proper measures to mitigate $PM_{2.5}$ in Busan should be investigated and established as soon as possible.

• Microbiology and Biotechnology Letters
• /
• v.45 no.4
• /
• pp.322-329
• /
• 2017

Two pilot-scale biocovers (PBCs) were installed in a landfill, and the methane ($CH_4$) concentrations at their inlets and outlets were monitored for 240 days to evaluate the methane removability. Consequently, the packing materials were sampled from the PBCs, and their potential $CH_4$ oxidizing abilities were evaluated in serum vials. The $CH_4$ concentration at the inlet of the biocovers was observed to be in the range of 23.7-47.9% (average = 41.3%, median = 42.6%). In PBC1, where a mixture of soil, earthworm cast, and compost (7:2:1, v/v) was employed as the packing material, the $CH_4$ removal efficiency was evaluated to be between 60.7-85.5%. In PBC2, which was filled with a mixture of soil, earthworm cast, perlite, and compost (4:2:3:1, v/v), the removal efficiency was evaluated to be between 29.2-78.5%. Although the packing materials had an excellent $CH_4$ oxidizing potential (average oxidation rate for $CH_4=180-199{\mu}g\;CH_4{\cdot}g\;packing\;material^{-1}{\cdot}h^{-1}$), $CH_4$ removal efficiency in PBC1 and PBC2 decreased to the range of 0-30% once the packing materials in the PBCs were clogged and channeled. Furthermore, seasonal effects exhibited no significant differences in the $CH_4$ removal efficiency of the biocovers. The results of this study can be used to design and operate real-scale biocovers in landfills to mitigate $CH_4$ buildup.

• The Korean Journal of Physiology and Pharmacology
• /
• v.22 no.1
• /
• pp.35-42
• /
• 2018

Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the $C_{max}$ value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their $T_{max}$ values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders.