• Journal of Environmental Impact Assessment
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• v.27 no.1
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• pp.56-72
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• 2018

North Korea has been in ecologically deficit state since 1966, despite of lack of energy and food resources. Trends of the Biocapacity (BC), the Ecological Footprint (EF), and the Ecological Deficit (ED) of North Korea were shown and five factors influencing on the Overshoot Rate (OSR) which is the ratio of the BC and the EF in North Korea was analyzed in this study. The five factors consist of two factors affecting to the EF and three factors affecting to the BC in North Korea. Two of the five factors are affecting to the EF those are population, the EF per capita (EFPC) which indicates the individual environmental consumption intensity, and three are affecting to the BC those are the land area, the yield factor, and the value multiplying the equivalence factor and the intertemporal yield factor. The EF has contributed more than the BC to the OSR. From 1966 to mid-1990s, the EFPC was the most contributing factor at about 60%, and after mid-1990s, population at about 40~60%. Contribution ratio of land area and the yield factor have increased after mid-1990s up to 15% and 18%, respectively. The BC of cropland which has decreased due to a decrease in productivity. In order to reduce the ED of North Korea, improvement of productivity of cropland and restoration of forest. Forest area has decreased significantly since 1990 in NK. And ways to solve the food shortage problem which influences on decrease of both productivity of cropland and forest area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.4
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• pp.295-304
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• 2020

The IPCC (Intergovernmental Panel on Climate Change) recommended the importance of preventive measures against extreme weather, and heat waves are one of the main themes for establishing preventive measures. In this study, we tried to analyze the heat vulnerable areas by considering not only spatial characteristics but also social characteristics. Energy consumption, popu lation density, normalized difference vegetation index, waterfront distance, solar radiation, and road distribution were examined as variables. Then, by selecting a suitable model, SLM (Spatial Lag Model), available variables were extracted. Then, based on the Fuzzy theory, the degree of vulnerability to heat waves was analyzed for each variable, and six variables were superimposed to finally derive the heat vulnerable area. The study site was selected as the Daegu area where the effects of the heat wave were high. In the case of vulnerable areas, it was confirmed that the existing urban areas are mainly distributed in Seogu, Namgu, and Dalseogu of Daegu, which are less affected by waterside and vegetation. It was confirmed that both spatial and social characteristics should be considered in policy support for reducing heat waves in Daegu.

• Environmental and Resource Economics Review
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• v.19 no.4
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• pp.733-752
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• 2010

This study applies the Luenberger indicator approach to estimate productivity of the Korean fossil-fueled power plants. A panel data set of 25 power plants was used. The method incorporates $CO_2$ emission as an undesirable output and shows that ignoring $CO_2$ emission overestimates the productivity change. There are two sources of overestimation. First, the usual method estimates productivity change ignoring the increase in $CO_2$ emission that occurred during the study period. Second, the productivity change estimated by the usual method that does not incorporate $CO_2$ emission is very sensitively affected by the change in operation rate. The paper decomposes the productivity change into the efficiency change and the technical change. The results show that the two sources contribute to the productivity change almost equally. It is also shown that the size and the pattern of productivity change are dependent on the plants' fuel types. Non-LNG power plants which saved their energy consumption and thereby reduced their $CO_2$ emission have achieved relatively high rate of productivity improvement.

• Environmental and Resource Economics Review
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• v.16 no.2
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• pp.213-237
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• 2007

Discussions on regionalization of the world crude oil markets have provided important implications for the establishment of national energy policies. In particular, due to arbitrage trading, if these markets are regionalized, Korea who imports approximately 80% of the annual oil consumption from a single region may be faced with a crucial problem. Therefore, in this study, we analyzed regionalization of the world crude oil markets using causality analysis as well as cointegration method to consider temporal relationship and time lags. To analyze regionalization, we chose Dubai price for the Middle East market, Brent for the European, WTI for the U.S., and Tapis for the East Asian. For the case that long-run equilibrium existed between market prices, we used vector error correction model to analyze causal relationship, and for the case that equilibrium did not exist, we used Hsiao (1981)'s framework that can consider asymmetric time lags in the model for causality analysis. By the results of cointegration analysis, there did not exist long-run equilibrium among Dubai price and the other prices. However, we found the causal relationship among Dubai price and the other prices with one to four weeks time lags. Therefore, in effect, we could conclude that the world crude oil markets are unified supporting Adelman (1984)'s hypothesis.

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.43-51
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• 2011

The recent development of the technology for wireless mobile computing and applied technology for location-based services has made it possible to support query processing faster than that in the past. However, some technological limitations on hardware and software still exist. The most critical aspects of query processing are accuracy and speed. For improving the accuracy, it is required that detailed information on the data involved in query processing be saved. In this case, the amount of information on the data increases, which decreases the speed. On the other hand, for increasing the speed, it is necessary to reduce the broadcast cycle, which enables rapid data acquisition as desired. In this case, because of insufficient index information, the listen time for the client increases, which may cause unnecessary energy consumption. Therefore, a trade-off occurs between the accuracy and speed. This paper proposes a hierarchical bitmap-based spatial index (HBI) as a solution for the aforementioned problems. HBI describes an object with 0 and 1 on the Hilbert curve map. It reduces the broadcast cycle by decreasing the index size on the basis of bit information and tree structure. Therefore, it is able to shorten the listen time and query processing time. In addition, HBI enables the detection of the locations of all the objects so that it is possible selectively listen to a broadcast. A performance evaluation of the proposed technique demonstrates that it is excellent.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.2
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• pp.160-164
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• 1999

Subsurface environments, including the intermediate vadose zone and aquifers, may be contributing to increased atmospheric concentrations of $N_2$O. Denitrification appears to be the major source of $N_2$O in the subsurface environment. In the intermediate vadose zone, the level of denitrifying activity is dependent on the soil morphology, particularly stratified layers within the soil profile, which impede water and solute movement and create conditions favorable for denitrification. Movement of organic C from the soil surface appears to support denitrifying activity by providing an energy source and increasing the consumption of $O_2$. Denitrirication and $N_2$O production have been observed in aquifers but appear to be of greatest significance in shallow unconfined aquifers. The lack of organic C, N $O_2$, or anaerobiosis is often a limiting factor for activity but seems to be site specific. The presence of denitrifying bacteria does not appear to be a major limitation, based on published results, but the ubiquity of denitrifiers in subsurface environments needs to be confirmed. The fate of the $N_2$O produced in subsurface environments is unknown. Transport of $N_2$O by up ward diffusion, by outgassing at contacts with surface waters, and by ground water use need to be quantified to determine the contribution to atmospheric $N_2$O. Contamination of subsurface environment with N $O_3$$^{ }$ and organics has the potential for increasing the contribution to atmospheric $N_2$O by enhancing denitrification .

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.706-713
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• 2017

This study compared and analyzed the water treatment efficiency and the applicability of water treatment plant using the existing Mechanical Rapid-Mixer by introducing the Non-powered Vortex Mixer to the domestic water treatment plant. For this study, fluid flow characteristics and head loss of a Non-powered Vortex Mixer are calculated by Computational Fluid Dynamics (CFD)respectively. The head loss rate inside the mixer was 11.30% when the inflow velocity was 0.5 m/sec, 16.27% at 0.6 m/sec and 21.44% at 0.7 m/sec, the head loss rapidly increased at the optimal velocity of 0.5 m/sec. For the inflow velocity of 0.5 m/sec, the turbulent intensity at the inlet was 2.37% and at the outlet was 7.83%, so there was sufficient mixing strength for the particulate matter and the coagulant. The result of the water quality of the treatment plants with the inflow velocity of 0.38 m/sec that was operated in three years after replacing all 12 units of the existing Rapid-Mixer with the Non-powered Mixer met the standards. Hence, it is possible to reduce the energy consumption of 64,143 ~ 65,306 kWh/year since the Rapid-Mixer is replaced by the Non-powered Vortex Mixer.

• Hwankyungkyoyuk
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• v.11 no.2
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• pp.130-143
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• 1998

This study was conducted as a preliminary step to establish a model for the practical application of environmental education related to food wastes collected from elementary school foodservices. Methods of treatment and present recycling status of food wastes in elementary schools in Kyonggido were surveyed. The consciousness of dieticians who have been serving for elementary school foodservices was also analyzed through the survey questions concerning environmental education for the reduction and recycling of food wastes. The results derived from this survey were as follows: The major portion of food wastes from elementary school foodservices was constituted with vegetables and soup, and an average amount of food wastes per day was highest in June and July. Therefore environmental education related to reduction of wastes was needed in the first semester of school terms, and the possible reduction of food wastes achieved through the proper planning of school foodservice menu was also needed. In most cases food wastes were collected and treated by animal growing farmers or composted by machines in school. In operating composting machines microorganism inoculant was mostly used but dieticians pointed out the problem of a nasty odor, insects, and high energy consumption. This situation means it has not been operated efficiently and suggests an efficiency problem of machine composting in elementary schools because composting itself is based on the aerobic digestion and high temperature fermentation which kills insects and harmful microorganisms. Elementary school dieticians in Kyonggido were aware that food wastes cause main pollution problem, and that food wastes are valuable resources which can be recycled, and recycling of food wastes is inevitable. But more than half of the schools surveyed have not been reused food wastes in school, so a proper model for recycling and reuse of food wastes in school grounds was thought to be needed. Environmental education programs related to food wastes have not been peformed in more than half of the schools surveyed. It was concluded that the following three plans will be helpful to reduce school food wastes. First, environmental education should be enforced, second, teachers' and dieticians' intensive teaching concerning food wastes should be needed, and finally establishment of a model for recycling and reuse of food wastes in school grounds and its application to environmental education would offer a valuable field experience to school students.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.38-45
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• 2016

The power transformation system of High Speed rolling stocks like KTX-Sancheon has shown excellent control capacities in the areas of riding comfortability, switching efficiency, safety and energy consumption due to technical developments in power-electronics, high speed & large scale integrated semiconductors and microprocessors. However, harmonics from IGBT, a high speed switching device used in the Convertor & Invertor equipment of rolling stocks have given rise to various problems in transformer substations, signaling systems, data transmission systems and facility monitoring systems. Especially, TI21 non-insulated track circuits have malfunctioned due to the influence of returning current harmonics which were generated at around of integer times of the number of power transformation equipment in the frequency domain. This paper, measures and analyzes various schemes to analyze the traveling path of the returning current harmonics generated due to the relationship between the rolling stocks and track circuits on site. Ultimately, theseschemes will be used to design high speed rolling stocks, AF track circuits and a common grounding network.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.949-958
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• 2008

This study was carried out to examine the association of age, nutrient intake, alcohol drinking and smoking on serum lipid and apolipoprotein levels in 100 healthy adults (54 males and 46 females). The serum total cholesterol, low density lipoprotein cholesterol (LDL-C) (p<0.05), apolipoprotein B (Apo B) levels, LDL-C:high density lipoprotein cholesterol (HDL-C) ratio, Apo B:apolipoprotein(Apo A-I) ratio and atherogenic index (AI) (p<0.001) were significantly higher in males than females, but HDL-cholesterol level was significantly lower (p<0.01) in males than females. The plasma ascorbic acid concentration had no difference in both genders. Most of nutrient intakes except Ca, vitamin A and vitamin $B_2$ were higher than RI (Recommended intake) in both males and females. The meal frequency per day was significantly higher (p<0.01) in males than females, while meal speed, the heaviest meal, meal quantity and meal regularity had no significant differences. The rates of drinking and smoking were significantly higher (p<0.01) in males (59.3%, 37.2%) than females (17.3%, 6.9%). The age was positively correlated with triglyceride level in males (p<0.05), and with total cholesterol (p<0.001), LDL-cholesterol (p<0.001), Apo B (p<0.01), LDL-C:HDL-C ratio (p<0.01), Apo B:Apo A-I ratio (p<0.05) and AI (p<0.01) in females. The levels of serum lipid and apolipoprotein were more correlated with protein intake than other macronutrient intakes in males, while those in females were more correlated energy, carbohydrate and lipid intakes than protein intake. The effect of drinking on serum lipid and apolipoprotein levels was bigger in males than females, while the effect of smoking on those was bigger in females than males. The plasma ascorbic acid concentration was positively correlated with HDL-cholesterol (p<0.05), Apo A-I levels (p<0.001), whereas negatively correlated with Apo B:Apo A-I ratio (p<0.05) in males. And that was positively correlated with HDL-cholesterol (p<0.05) in females. These results suggest that moderate macronutrient intake, less alcohol consumption and non-smoking were necessary to maintain healthy lipid profile with aging in adults.