• Journal of Wetlands Research
• /
• v.18 no.3
• /
• pp.324-329
• /
• 2016

Constructed wetlands are widely applied in urban and rural areas for various purposes such as pollutants reduction, acquisition of eco-spaces and habitats, flooding reduction, acquisition of water resources and environmental education. Since the design of constructed wetlands utilizes ecosystems, special consideration must be given to ecological mechanisms, environmental mechanisms and hydrological mechanisms. To ensure the sustainable functionality of constructed wetlands, it is necessary to achieve stable flow rate and velocity, and remove sediments to ensure sufficient space for detention. To enhance the efficiency of constructed wetland sedimentation basins, this study determined the optimal position for baffle installation, and applied Computational Fluid Dynamics (CFD) to the cross-sectional design of wetlands. CFD analysis revealed that the decrease in flow velocity with baffle installation enhanced the efficiency of sedimentation of particulate matters. Vertical baffles had higher sedimentation efficiency than those with an inclined angle. When vertical baffles were installed in the sedimentation basin of a hybrid constructed wetland to reduce non-point source pollutants in urban areas, the average flow velocity within the basin decreased by 10~30%, while the sedimentation efficiency improved by 1.3~1.5 times. The application of CFD to constructed wetlands is expected to improve the cost efficiency of designing hybrid constructed wetlands with high removal efficiency.

• Journal of Digital Convergence
• /
• v.15 no.7
• /
• pp.97-109
• /
• 2017

Domestic vehicle penetration rate is growing at 3% per year, but consumers are increasingly buying used cars due to steady price hikes Nevertheless, the used car export market is expected to decline due to import regulations of major countries and the low grade environment of Used car export complex. Therefore, this study using Fuzzy-AHP was aimed to find operational factors of Used car logistics complex and establish a practical management plan of Used car logistic complex in incheon port. Fuzzy-AHP is the method that can be calculated weight of multi-level criteria and change linguistic ambiguity of human to Fuzzy Number. So it's able to propose the realistic decision making alternatives. As a result of the literacture reviews, present study focused on the analysis of the present situation of the logistics of the used car and the activation of the complex, suggested the activation plan and activation of the logistics complex. In the analysis of operational factors, logistic complex cost factors were found to be the most important factors by recording the weighted value of 0.306 in the above factors. The detailed factors were as follows: rent, accessibility, and logistics site size. It is necessary to compute competitive rent for the highly-advanced used car logistics complex, and to realize the rental support policy and to consider designating the free trade zone. In addition, it is necessary to expand the access infrastructure and secure the scale of the company for overseas buyers, and it is necessary to improve the overall government laws and introduce IT system for the future.

• Korean Institute of Interior Design Journal
• /
• v.24 no.5
• /
• pp.108-116
• /
• 2015

This study intends to research the spatial characteristics of Asian interim housing that accommodates sufferers pro tempore after disasters. The scope of this research covers the interim spaces used for housing people after natural disasters that occurred in Asia for the past fifteen years. Within this scope, literature review was conducted as the basis to derive the characteristics and environmental elements of interim housing, which provided the criteria to compare and evaluate cases of interim housing along with characteristic elements required of interim housing found in previous studies. According to literature review, interim housing can be classified by life-span, region, economy, climate, type, number of household, square measure, residential cost, structure/material, and service life. Within the scope of the present research, literature review showed a total of twenty-eight cases of interim housing in fifteen countries revealing a high rate of disaster occurrence in the subtropic and tropic climate of Southeast Asia. A great percentage of interim housing was used for long-term stay of over a year. The structure of interim housing varied from lightweight steel, wooden, masonry, membrane, to traditional structure and the type were divided into temporary shelter, transitional housing, temporary housing, and permanent housing. Followed by literature review, the characteristics required of post-disaster interim housing were analyzed based on previous research and case studies. The characteristics of interim housing can be divided into environmental, technological, and socio-cultural ones. Sub-characterical items according to such division include amenity, health, surroundings, structure, convenience, eco-friendliness, safety, communication, and locality. As a result of evaluation, most items met the required characteristics of interim housing, while technological characteristics such as structure and convenience varied with the types of interim housing and appeared even unnecessary in some cases. According to analysis, amenity is maintained through the structural and material characteristics of interim housing and is also facilitated by increasing number of infrastructure such as educational, sanitary, and convenience facilities provided by the governmental and organizational bodies. It is expected that this study will be utilized as preliminary data for follow-up studies that improve the environment of post-disaster interim housing suitable for domestic circumstances in environmental, technological, and socio-cultural respects.

• International Area Studies Review
• /
• v.15 no.2
• /
• pp.247-273
• /
• 2011

This study analyzes the impacts on the M&A and greenfield of macroeconomic variables of home and host countries, after identifying current status and characteristics of the M&A and greenfield related to the entering way of Korean firms in China. Main empirical results are summarize as follows. First, as for foreign exchange variable, the decreased value of Korea won shows the negative correlations with both of the greenfield and M&A. Second, the real interest rate of Korea to measure the cost of capital is not significant statistically. Third, while the host country's stock market index, Shanghai Comprehensive Index, shows the expected negative correlations with the investment in the case of small & medium firm and light industry, it shows the positive correlations which is not consistent with general expectation in the case of large firm and heavy industry. Fourth, the openness of host country shows the positive correlations with both of the greenfield and M&A. Finally, in regard to the M&A, China's GDP to measure the market size of host country is not significant statistically while it shows the strong positive relationship with the greenfield investment.

• Korea Real Estate Review
• /
• v.28 no.2
• /
• pp.7-20
• /
• 2018

This paper has statistically analyzed the determining factors that affect office building sale prices by focusing on strata property sales through the hedonic price function. In this study, 1,171 office building transaction cases were analyzed in Seoul from 2000 to 2017. To determine the influence of various factors on office building sale prices, independent variables included factors that represented macroeconomic characteristics, locational characteristics, physical characteristics, and deal characteristics. The analysis of the strata property sales, which is a major concern in this study, showed that strata property sales enjoyed a discount of about 1.56 million won per pyeong out of the entire sales. In terms of the discount rate, strata property sales were at a 12.6% discount compared to entire property sales, so it was found that strata property sales significantly influenced office building selling price. This is due to the fact that the owner of the strata property encounters more difficulties in distributing cost than the sole proprietor in terms of property rights and the exercise of management rights. The results of this study are expected to contribute in securing transparency in transactions and risk management strategies in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.11
• /
• pp.506-512
• /
• 2018

The fine dust generated in the home and restaurant business occupies a low ratio of about 4% of the total fine dust emissions. However, at the foodservice business, the rate of change of the pollutant concentration is very high, so that the temporary fine dust concentration can be measured up to 60 times. The pollutants generated from non-industrial combustion plants consist of particulate fine dust and gaseous organic compounds. To remove these pollutants, cleaning dust collection system, which is an effective system for simultaneous removal of gaseous and particulate matter, is applied. This is a method of increasing the probability of diffusion capture of the Brownian motion by pressurized liquid injection method using the atomizing nozzle. The dust removal efficiency of the fine dust collecting system was analyzed by nozzle spraying air pressure condition and angle using the manufactured fine dust removing system. As a result, it was confirmed that the efficiency of removal of fine dust and gaseous organic compounds was more than 90%. The developed system is expected to be highly usable in the future because it can remove particulate dust from the existing plant hood system without any installation cost.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.1
• /
• pp.153-160
• /
• 2022

This study presents the bogie arrangement of the load-out system for on-ground shipbuilding. The load-out system is one of the most important systems to perform the bogie arrangement of the on-ground shipbuilding technique without dry dock facilities, and this system is composed of four pieces of equipment: bogies, driving bogie with motors, trestles, and power packs. Also, the bogie arrangement analysis (BAA) is employed to simply calculate the reaction forces at the trestle for structural safety. In this context, the purpose of this study is to propose an optimal design method to perform the bogie arrangement satisfying structural safety requirements with minimal cost. It is expected that the proposed methodology will contribute to the effective practice as well as to the improvement of competitive capability for shipbuilding companies at the on-ground shipbuilding stage. Furthermore, we describe some problems and their solutions of the deformation that may occur in the bottom of the hull during the load-out process. As a result, it is shown that we applied it to the 114K crude oil tanker (Minimum bogie 54EA) and the 174K CBM LNG carrier (Minimum bogie 88EA), it can minimize the number of bogie and critical risks (Safety rate 1.61) during the load-out of on-ground shipbuilding. Through this study, the reader will be able to learn successful load-out operation and economic shipbuilding in the future.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.2
• /
• pp.239-246
• /
• 2021

Unification means the change of the economic system from 'Planned Economy' of the North Korea to 'Market Economy' of the South Korea. Therefore, it may cause confusions and difficulties for North Koreans who have been under planned economy for ages. So, we need to take the perspective of behavioral economics for the effective education. First of all, it is about overall finance, which contains the record of financial transactions, effect of inflation, investors' bounded rationality, and choice difficulty of financial products. Second, it is about borrowings, which includes the credit management, interest rate of difference among financial institutions. Third, it is about investment on financial products, which includes the effect of cost on returns, difference between compound interest and simple interest, trade-off between expected return and risk, market and non-market risks, the importance of diversification, and passive & aggressive investments.

• Journal of Navigation and Port Research
• /
• v.47 no.6
• /
• pp.401-409
• /
• 2023

This study compared and analyzed the performance of a distributed area search algorithm and a distributed probability search algorithm based on information exchange between ships. The distributed algorithm is a method that can search for an optimal avoidance route based on information exchange between ships. In the distributed area search algorithm, only a ship with the maximum cost reduction among neighboring ships has priority, so the next expected location can be changed. The distributed stochastic search algorithm allows a non-optimal value to be searched with a certain probability so that a new value can be searched. A circular-based ship collision avoidance model was used for the ship-to-ship collision avoidance experiment. The experimental method simulated the distributed area search algorithm and the distributed stochastic search algorithm while increasing the number of ships from 2 to 50 that were the same distance from the center of the circle. The calculation time required for each algorithm, sailing distance, and number of message exchanges were compared and analyzed. As a result of the experiment, the DSSA(Distributed Stochastic Search Algorithm) recorded a 25%calculation time, 88% navigation distance, and 84% of number of message exchange rate compared to DLSA.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.34 no.1
• /
• pp.1-7
• /
• 2024

β-Ga₂O₃ is a material with a wide band gap of ~4.8 eV and a high breakdown-voltage of 8 MV/cm, and is attracting much attention in the field of power device applications. In addition, compared to representative WBG semiconductor materials such as SiC, GaN and Diamond, it has the advantage of enabling single crystal growth with high growth rate and low manufacturing cost [1-4]. In this study, we succeeded in growing a 10 mm thick β-Ga₂O₃ single crystal doped with 0.3 mol% SnO₂ through the EFG (Edge-defined Film-fed Growth) method using multi-slit structure. The growth direction and growth plane were set to [010]/(010), respectively, and the growth speed was about 12 mm/h. The grown β-Ga₂O₃ single crystal was cut into various crystal planes (010, 001, 100, ${\bar{2}}01$) and surface processed. The processed samples were compared for characteristics according to crystal plane through analysis such as XRD, UV/VIS/NIR/Spec., Mercury Probe, AFM and Etching. This research is expected to contribute to the development of power semiconductor technology in high-voltage and high-temperature applications, and selecting a substrate with better characteristics will play an important role in improving device performance and reliability.