• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.352-359
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• 2018

As a fuel for ship propulsion, liquefied natural gas (LNG) is currently considered a proven and reasonable solution for meeting the IMO emission regulations, with gas engines for the LNG-fueled ship covering a broad range of power outputs. For an LNG-fueled ship, the LNG bunkering process is different from the HFO bunkering process, in the sense that the cryogenic liquid transfer generates a considerable amount of boil-off gas (BOG). This study investigated the effect of the temperature difference on boil-off gas (BOG) production during ship-to-ship (STS) LNG bunkering to the receiving tank of the LNG-fueled ship. A concept design was resumed for the cargo/fuel tanks in the LNG bunkering vessel and the receiving vessel, as well as for LNG handling systems. Subsequently, the storage tank capacities of the LNG were $4,500m^3$ for the bunkering vessel and $700m^3$ for the receiving vessel. Process dynamic simulations by Aspen HYSYS were performed under several bunkering scenarios, which demonstrated that the boil-off gas and resulting pressure buildup in the receiving vessel were mainly determined by the temperature difference between bunkering and the receiving tank, pressure of the receiving tank, and amount of remaining LNG.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.482-487
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• 2017

It is necessary to respond to criminal cases on board of pelagic fishing boats in the international waters with domestic legal judgement and international legal judgement due to a natural limitation by geographical long distance while it is possible to deal with domestic criminal cases with prompt response by using air crafts or patrol vessels. In other words, according to the flag of the vessel, the legal status of the water where is the crime scene, the nationalities of the victim and the perpetrator, it is required to judge if Korea can exert their jurisdiction and there is an issue if Korea Coast Guard exert their law enforcement effectively with this natural problem. In this paper, I propose a systemic improvement for a swift investigation for henceforth similar case's occurrence by analyzing the jurisdiction, the suspect's handling, the basic cause of the murder on-board which are based on the case of the vessel No.803 Gwang-Hyeon which was happened recently.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.223-228
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• 2010

This experiment was conducted to select optimal cultivars of long leaf vase life for flower arrangements among 21 Hosta cultivars that were selected based on their ornamental value. As a result of the investigation, the cultivar with the longest leaf vase life was 'June' with 29 days record. The cultivars with a more than 10 days record were 'Remember Me', H. lancifolia var. grandiflora, 'Grand Marquee', 'Dress Blue', 'Blue Dimples', 'Frosted Dimples', 'Birchwood Park's Gold', 'Krossa Regal', and 'Paradise Power'. These 10 cultivars had a high chlorophyll content, and had low chlorophyll content changes over time and were high in water absorption. The 10 selected cultivars had equal characteristics of increase in chlorophyll content within a certain period of time. These cultivars have a longer vase life when compared to others. This indicates the potential to develop better materials be use with flower arrangements.

• Smart Structures and Systems
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• v.20 no.2
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• pp.247-261
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• 2017

In the field of dynamic measurement and structural damage identification, it is generally known that modal frequencies may be measured with higher accuracy than mode shapes. However, the number of natural frequencies within a measurable range is limited. Accessing additional forms of modal frequencies is thus desirable. The present study is concerned about the extraction of artificial boundary condition (ABC) frequencies from modal testing. The ABC frequencies correspond to the natural frequencies of the structure with a perturbed boundary condition, but they can be extracted from processing the frequency response functions (FRF) measured in a specific configuration from the structure in its existing state without the need of actually altering the physical support condition. This paper presents a comprehensive experimental investigation into the measurability of the ABC frequencies from physical experiments. It covers the testing procedure through modal testing, the data processing and data analysis requirements, and the FRF matrix operations leading to the extraction of the ABC frequencies. Specific sources of measurement errors and their effects on the accuracy of the extracted ABC frequencies are scrutinised. The extracted ABC frequencies are subsequently applied in the damage identification in beams by means of finite element model updating. Results demonstrate that it is possible to extract the first few ABC frequencies from the modal testing for a variety of artificial boundary conditions incorporating one or two virtual pin supports, and the inclusion of ABC frequencies enables the identification of structural damages without the need to involve the mode shape information.

• Korean Journal of Environment and Ecology
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• v.24 no.1
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• pp.37-45
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• 2010

This study was conducted to provide a database for biotope conservation and restoration of the Jeonju region in North Cheolla Province. To accomplish this task, investigations were made on the characteristics of the distribution pattern of naturalized plants in the region. From May to June 2008, the flora and lists of naturalized plants were investigated and, based on these data the ratio of naturalization was calculated. The results of this investigation areas follows: a total of 113 families and 54 species were found in the flora. The naturalized plants among them amounted to 19 families and 54 species. The ratio of naturalization was most high in the biotope type of rural dried stream(36.4%). The biotype that showed the lowest ratio of naturalization was coniferous natural forest type, which had no naturalized plants in it. The average naturalization ration of the Jeonju region turned out to be 18.9%, which is similar to that of other mid-size cities in Korea.

• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.415-422
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• 2008

Drinking water treatment is enhanced by coagulant dosages and chlorine injection because of pH increase in raw water in droughty seasons such as spring and fall. But water quality deterioration is occurred by increase in residual aluminium and disinfection by-products. Coagulation process can be used to control natural organic matter (NOM) during water treatment. The effect of coagulation process appeared to depend on the pH of water rather than coagulant dosages. In this study, for water treatment in high pH season $H_2SO_4$ was applied for pH adjustment at full scale. Before and after pH adjustment by $H_2SO_4$ injection, water quality of drinking water was evaluate. In the result of investigation of total organic carbon (TOC) removal in high pH season, TOC was removed approximately 30~40%, which showed decrease in water treatment efficiency. Also, it is increased both particle numbers and residual Al concentration in the water. After $H_2SO_4$ injection for adjustment to pH<7.5 in settled water, treated water turbidity decreased in 0.047 NTU from 0.059 NTU, and particle numbers of filtered water decreased in 20/mL from 90/mL. On the other side, TOC removal efficiency increased in approximately 10% after adjustment of pH. In the result of decrease in pH in raw water through more coagulants and prechlorine without $H_2SO_4$ injection, trihalomethanes (THMs) concentration increased in $16{\mu}g/L$ from $8{\mu}g/L$.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.80-83
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• 2008

As SOC (Social Overhead Capital) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, we may need to introduce a compulsory ventilation system as well as natural ventilation mechanism. The natural ventilation mechanism is enough for short tunnels, meanwhile longer tunnels require a specific compulsory ventilation facility. Many foreign countries already have been devoting on development of effective tunnel ventilation system and especially, some European nations and Japan have already applied their developed tunnel ventilation system for longer road tunnels. More recently, as the quality of life improved, our concerns about safety of driving and better driving environment have been increased. In order to obtain clearer and longer driving view, we are more interested in EP tunnel ventilation system in order to remove floating contaminants and automobile exhaust gas. Evan though it's been a long time since many European countries and Japan applied more economical and environment-friendly tunnel ventilation system with their self-developed Electrostatic Precipitator, we are still dependant on imported system from foreign nations. Therefore, we need to develop our unique technical know-how for optimum design tools through validity investigation and continuous possibility examination, eventually in order to localize the tunnel ventilation system technology. In this project, we will manufacture test-run products to examine the performance of system in order to develop main parts of tunnel ventilation system such as electrostatic precipitator, high voltage power generator, water treatment system, etc.

• Journal of Environmental Policy
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• v.8 no.3
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• pp.1-26
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• 2009

In the 1990s, when the viewpoint that an ecosystem is a single network within a specific region was adopted, the preservation and management of natural ecosystems was proposed. With regard to Northeast Asia, the expansion of trans-boundary pollution due to rapid development and the swift destruction of the natural environment emphasize the necessity for environmental cooperation. The Northeast Asia region made up of South Korea, North Korea, three northeastern prefectures in China, the Russian far-east, and parts of Mongolia were selected to be analyzed for an ecological network. The significance of this study lies in the development of a methodology for building a Northeast Asian ecological network through the use of satellite images. Regarding the methods of analysis, stable habitats for four priority species were selected to be performed using overlay analysis. The result of the analysis of the ecological networks in the whole Northeast Asia region showed that there were key areas partly dispersed in the Korean Peninsula, but whether the key areas would be maintained in the long term is unknown. As for China, key areas were concentrated in the border areas around the Tumen River and in parts of the three northeastern prefectures. Russia had wide-ranging areas that could function as stable habitats for most species. As a result of the actual conditions of the ecological networks, most of the Northeast Asia region, including the Korean Peninsula, was in poor condition, requiring appropriate measures and their operation as soon as possible. Also, it was revealed that further investigation and research was necessary for border areas that were identified to be key areas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.259-267
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• 2020

This study measured the Particulate Matter (PM) concentration according to altitude (30 m, 60 m, 90 m, 120 m, and 150 m) in three different environments: a construction site, natural environment (arboretum), and residential area. PM_2.5 and PM₁₀ values at 30 m above the construction site were 18.63 ㎍/㎥ and 24.23 ㎍/㎥ while values at 150 m were 10.89 ㎍/㎥ and 10.61 ㎍/㎥, respectively, indicating the average concentration decreased as altitude increased. PM_2.5 and PM₁₀ values at 30 m above the natural environment were 9.03 ㎍/㎥ and 11.21 ㎍/㎥ while those at 150 m were 3.42 ㎍/㎥ and 3.57 ㎍/㎥, respectively, showing lower average concentrations as altitude increased. PM_2.5 and PM₁₀ values at 30 m above the residential area were 10.65 ㎍/㎥ and 12.06 ㎍/㎥ while those at 150 m were 4.24 ㎍/㎥ and 5.17 ㎍/㎥, also demonstrating lower PM concentrations as altitude increased. The PM concentrations decreased as altitude increased at all tested sites and also decreased between environments in the following order: construction site, residential area, and natural environment. The results of this study are significant because PM concentrations were measured at various altitudes at different land-use sites. The results are expected to serve as basic data for decision-making in both regional and urban planning.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.2
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• pp.49-60
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• 2014

This study was conducted to evaluate the effect of forest fire on natural distribution and regeneration of Pinus densiflora Sieb. & Zucc. in Goseong, Gangwon province, Korea. After 13 years of the last forest fire in 2000, five investigation plots ($10m{\times}10m$) in each of rocky land and ridge, the well-known location as a favorite site for natural distribution of P. densiflora, were set to investigate stand characteristic and soil environment including physico-chemical properties and moisture contents of soil. Also, five investigation plots in slope area were set and investigated as well. The concentration of organic matter, total nitrogen, and exchangeable nutrients ($K^+$, $Ca^{2+}$, $Mg^{2+}$) were highest in the slope while the soil in the rocky land showed the lowest concentration of organic matter, total nitrogen, available $P_2O_5$, and exchangeable nutrients ($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$). The soil in the slope only showed higher concentration of total nitrogen, $K^+$ and $Ca^{2+}$ than the unburned area in Goseong. Mean soil moisture contents in the rocky land (5.77%) were lowest while the slope (15.78%) and the ridge (15.27%) showed almost three times as much than the rocky land. P. densiflora was dominant in the rocky land and Quercus spp. were dominant in the ridge and slope. The average proportion of P. densiflora was highest in rocky land (58.4%, 14.6 trees per plot) followed by the ridge (25.2%, 7.8 trees per plot) and the slope (11.3%, 3.4 trees per plot) while the average height of P. densiflora was highest in slope (277cm) followed by the ridge and the rocky land. The height and crown width of Quercus spp. were higher than P. densiflora in the every plot. The results suggest that P. densiflora may be able to naturally regenerate and survive in the rocky land after the fire while P. densiflora in the ridge and the slope are suppressed by Quercus spp.