• International conference on construction engineering and project management
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• 2015.10a
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• pp.213-216
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• 2015

Despite the significant increase of Korean contractors in the international construction market, many SMCCs (Small & Medium Construction Companies) have suffered in the global financial crisis, and some of them have been kicked out of the international market after experiencing huge losses on projects. SMCCs face obstacles in the international market, such as an insufficient ability to gather information and inappropriate management of associated risks, which lead to difficulties in establishing effective business strategies. In other words, making immature decisions without an effective business strategy may cause not only the failure of one project but also the bankruptcy of the SMCC. To overcome this, the research presented herein aims to propose a decision support system for SMCCs, which would screen projects and make a go/no-go decision at the early stages of international projects. The proposed system comprises a double axis: (1) a profit prediction model, which evaluates 10 project properties using an objective methodology based on a historical project performance database and roughly suggests expected profit rate, and (2) a feasibility assessment model, which evaluates 17 project environment factors in a subjective and quantitative methodology based on experience and supervision. Finally, a web-based system is established to enhance the practical usability, which is expected to be a good reference for inexperienced SMCCs to make proper decisions and establish effective business strategies.

• Journal of KSNVE
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• v.11 no.2
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• pp.329-335
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• 2001

The analytical model of the ground wave can be used for the prediction of the noise level from a source above a plain and homogeneous ground surface with no obstacles nearby. Sound propagation along the surface of the ground can be affected by the roughness of the ground surface and the direction of the wind. The effects of the ground surface and the wind can be formulated in terms of the ground coefficient and the noise source parameter. Upward and downward conditions can also be addressed by considering the direction of the wind. The ground coefficient and the noise source parameter are estimated using the measured noise levels of two points under particular environmental condition, and the noise levels of arbitrary points under the same environmental condition can be estimated. The proposed method can be utilized to estimate the noise level of specific noise environment and its validity was confirmed with the results of actual field measurement.

• Journal of Environmental Science International
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• v.21 no.4
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• pp.391-399
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• 2012

This study proposes lighting simulation approach to assess lighting quality on motor ways and walk ways considering each type of form and growth of roadside trees. Simulation approach to assess quality of lighting is frequently used for lighting design which guarantees secure of drivers and pedestrians during the night time. But, road side trees which have diverse benefits for citizens acts on obstacles during night time needs lighting. The results of this study shows a possible way for tuning the aims of both lighting and road side tree. It will be possible to develop harmonic design standards for road way lighting if further study achieved based on the result of this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1865-1870
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• 2000

Sound propagation along the surface of the ground can be affected by the roughness of the ground surface and the direction of the wind. Noise Source parameter and ground factor are estimated using the measured results of two points under particular environmental condition, and the noise level of arbitrary points under the same environmental condition can be estimated. The results can be used for the prediction of the noise level from a source above a plain and homogeneous ground surface with no obstacles nearby. Upward and downward conditions are also addressed in addition to ground effect. The proposed method can be utilized to estimate the noise level of specific noise environment and its validity was confirmed with the results of actual field measurement.

• Journal of Environmental Science International
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• v.12 no.1
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• pp.69-76
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• 2003

When houses or buildings are adjacent to roads, with no effective prevention of road traffic noise, neighbors are exposed to it. It is important to understand the properties of sound propagation before taking a countermeasure against road traffic noise. It is easy to estimate the properties of sound propagation without obstacles, but very difficult and complex to estimate them with ones. The purpose of this study is to present a useful tool that can estimate the properties of sound propagation. In the beginning of this study, we investigated the attenuation of road traffic noise with two pillar buildings, and presented practical approximate calculation method, and verified that through scale model. The outcomes from this study are as follows : (1) Over second reflection sound waves can be ignored. (2) Diffraction sound waves that happen when reflection sound and first diffraction wave are projected at the wedge of other building can be ignored.

• Journal of Ecology and Environment
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• v.44 no.4
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• pp.207-211
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• 2020

Adult land crabs generally live on land while their larvae live in the sea. In the case of Sesarma haematoche, female crabs migrate from land to sea to release the larvae at the high tide of syzygy night. Artificial structures along coastal areas are being obstacles for the migration of land crabs and causing synchronized roadkills on coastal roads during breeding migration. In this research, we compared the sex ratios of crab populations in coastal areas with coastal roads and uninhabited island areas with no road. The proportion of females in inland habitats with coastal roads was significantly smaller than island habitats. In particular, females are exposed to the risk of annually repeated roadkills, and the proportion of females decreases rapidly with their growth. If this tendency is general for land crab populations in the coastal areas with roads, significant road mortality of female land crabs during breeding migration can lead to severe population decline in coastal areas. Therefore, it is necessary to take an action to save land crabs crossing coastal roads.

• Hwankyungkyoyuk
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• v.13 no.1
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• pp.96-110
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• 2000

There are some considerations that must take into account in environmental education in the aspect of the difference of value clarification between ecological and economic viewpoint on environment. Although we have a tendency to think that the differences are unavoidable because we are on the economy-oriented life, we should realize that such emphasis to economics comes from the differences between ecological and economic view point on environment. We have lived and thought on the basis of Economic view point, especially, environmental policies are established on the basis of economic efficiency. But this tendency has become great obstacles to environmental ethics education because it dilutes the reason of natural preservation and removes the fundamental reasons why the nature should be preserved. Therefore it is very difficult to balance the value clarification between economic and ecological viewpoint in actual life. Furthermore, environmental problems can not be solved only through economic approach, because of their limits to belief solving from providing incentives. It is very important to make people have a way of thinking which economic activities and debates can be made on the ecological resources. Therefore we can compare this relation to CHAE-YONG founded on Buddism and Chinese philosophy. CHAE means essence of every reaction in the cosmos, and YONG means the reaction itself. CHAE is regarded to ecological resources, and YONG is thought to every-day economic activities. YONG is not able to existwithout CHAE. If economic activities can be done on the basic limit of ecological resources, we can build suitable environment to living condition. We call this appropriate environment as SANG. In other words, the connection of CHAE-YONG-SANG means ecological resources - economic activities - sustainable environment. It is realized that the relations between economics and ecology should be equalized for the balanced environmental ethics education. This study tries to get out of unbalanced relations between economics and ecology from the persepectives of CHAE-YONG-SANG and it was done to suggest an alternative environmental ethics education program

• Journal of Environmental Impact Assessment
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• v.8 no.2
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• pp.65-71
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• 1999

Characteristics of food garbage discharged from primary schools in Seoul Metropolitan city were analysed from a recycling point of view. The results of study are epitomized as follows : 1. Factors of generation of food garbage are mainly an unbalanced diet habit, indifference of class teachers, and worn-out cooking equipments. 2. Measures of reduction are principally a written message to parents, broadcasting in the school, and instructions. 3. Methods of recycling are mainly feed stuff, composting by school itself, composting on commission, and making feed stuff on commission. 4. Obstacles of food garbage recycling are a nasty smell of composting apparatus, an excessive fuel consumption of composting apparatus, a high concentration of salt, and an unstable demand for feed stuff and compost produced from food garbage. 5. Correlation factors are like follows : the number of feeding children and food garbage weight after cooking is 0.35, total food garbage generated and monthly treatment cost of food garbage is 0.20, individual school lunch expenses and food garbage weight after cooking is -0.10, individual school lunch expenses and food garbage generated per capita is 0.02, and individual school lunch expenses and monthly treatment cost of food garbage is 0.03.

• Journal of computational fluids engineering
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• v.21 no.2
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• pp.32-39
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• 2016

The Gradient Biome is a unique and large greenhouse(length 200 m, width 50 m, height:40 m) in which the elements of the weather, such as temperature and humidity, are controlled and reproduced in such a way as to create a continuous gradient from the tropical to frigid zones along specified longitudinal or transvers lines on the earth. One of the main purposes of the Gradient Biome is to observe the possible responses of the ecosystems (mainly plants), which are to be corresponding to each test climate and be introduced in the Biome, to the expected global warming. As one of the expected responses is the shift of the ecosystem(s) toward the region of suitable environment, there should be no artificial obstacles, which can prevent the shift, inside the facility. However, it is important but not so easy to find the ways of how the temperature and humidity in the Biome could be reproduced since the environmental variables tends to be homogeneous. In this paper, numerical simulations were carried out to find the effective control methods for air temperature and humidity inside the real scale Biome. One of the contributed solvers of OpenFOAM, which is an open source physics simulation code, was modified and used for the simulations.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.91-96
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• 2006

Many small scale Sewage Treatment Plants (STPs) are currently being constructed at many rural areas. The STPs in rural area suffer from low concentration and large inflow quantity fluctuation during wet weather mainly due to illicit combined sewer system. Sequencing Batch Reactor (SBR) is a process effectively coping with these obstacles. The main objective of this study was to evaluate SBR with high hydraulic loading and low inflow concentration. The operating conditions tested were: organic loading rate = $0.17-0.42KgBOD/m^3/d$, hydraulic loadings = $12.1-61.5m^3/m^2/d$, average MLSS concentration = 2500 mg/L, F/M ratio = 0.026-0.17 KgBOD/Kg MLSS, HRT = 9-12 hr HRT, and SRT = 5.6-33.6 days. Organic loading rate on SBR did not impact significantly on BOD and SS removal efficiencies. To increase treatment efficiencies, low hydraulic loading rate with low concentration was required. The results suggested that low influent concentration with high inflow rates during wet weather requires extended time for settling.