• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.2
• /
• pp.220-228
• /
• 2007

In this study, effective simultaneous nitrification and denitrification reaction was accomplished in a completely mixed single bioreactor. As the important factors on the reaction, optimal DO concentration and effective range of influent C/N ratio was investigated with the synthetic wastewater. Experimental results show that stable nitrogen removals were accomplished with 0.5 mg/L DO concentration and over 7 C/N ratio. Nitrogen removal efficiency of the real municipal wastewater was low with 0.5 mg/L DO concentration because of its low C/N ratio. The increment of the C/N ratio at the inflow of the municipal wastewater with addition of external carbon source (glucose) over 7(up to 14) shows over 70% nitrogen removal in the single bioreactor.

• Journal of the Korean association of regional geographers
• /
• v.10 no.1
• /
• pp.53-66
• /
• 2004

There are various granite landforms including block stream(natural monument No. 435) within Mt. Biseul, in Daegu city. The Daegyunsa(temple) and community of rhododendron around the summit of the mountain provide visitors many objects o( interest in cultural & ecological heritage. This paper aimed to develope nature trails of various type according to visitor's characteristics. 1) Various granite landforms develope along with the main path up the mountain(block stream-gnamma-exfoliation-poligonal cracking-talus-core stone-sheeting joint-tor-free face-high flat summit). 2) The explanatory note on terminology, origin, characteristics of geomorphic resources are developed in this paper for the first time. 3) In Consideration of the path line of flow of visitor, the best field study sites and the most effective nature trails are designed for visitor. 4) Three nature tails are designed for visitor according to the type and the length of visitor's stay.

• 한국방재학회:학술대회논문집
• /
• 2011.02a
• /
• pp.180-180
• /
• 2011

도시지역에서 빗물은 대부분 도로를 통해 이동하고 배수된다. 도로의 배수시설은 도로면의 안전을 확보하기 위한 목적뿐만 아니라 도로 이외의 지역에 흐르는 유출수의 배수를 위한 기능도 포함하고 있다. 그러나 도로변에 설치되어 있는 빗물받이 등과 같은 하수도 시설을 통해 빗물이 원활하게 배수되지 않으면 노면수가 정체되고, 이 노면수가 인근 주택가로 유입되어 침수를 피해를 가중시키는 경우도 있다. 빗물받이 설계 시 설계빈도를 차집능력에 상위하는 충분한 여유를 두고 설치하더라도 빗물받이가 도시지역에서 발생하는 유송토사, 쓰레기, 낙엽 및 담배꽁초 등에 의하여 막히게 되면 유입구의 순 면적이 감소하게 되어 빗물받이가 제 기능을 다하지 못하는 경우 또한 발생하고 있다. 이렇게 빗물받이로 유입되는 부유잡물들은 퇴적되어, 우수관로 내에서 썩어 수질을 악화시키거나 악취의 원인이 되기도 한다. 본 연구에서는 빗물받이의 이 같은 문제점을 개선할 수 있는 비노출 배수로의 배수효율을 수리실험을 통해 검토하였다. 도로의 측면에 비노출 배수로를 설치하였을 경우 도로위에 수심이 거의 발생하지 않으면서 배출할 수 있는 최대 유량은 1.67 l/s였고, 서울시를 기준으로 설계빈도 10년에 대하여 본 연구의 실험도로 규격에서의 유출량이 1.09 l/s임을 고려할 때 10년 빈도 강우강도 발생 시 비노출 배수로가 충분한 여유를 가지고 배수 시킬 수 있을 것으로 판단된다. 본 실험도로의 규격에서 1.67 l/s의 유출량이 발생하기 위한 강우강도는 서울시를 기준으로 100년 빈도에 상응하는 강우강도로 비노출 배수로에 막힘이 없는 경우 100년 빈도의 강우시에도 노면수 배출이 가능하였다. 쓰레기와 모래와 같은 부유잡물이 배수로를 막고 있다 하더라고 배수효율 저하는 크게 발생하지 않았다. 그러나 흙탕물이 유입되는 경우 흙탕물이 배수로의 공극을 차단하는 현상이 나타났고 이는 도로위의 수심은 증가시켰다. 흙탕물이 유입된 후 배출가능 유량을 강우강도와 빈도를 환산한 결과 서울시를 기준으로 6.8년에 상응하였다. 따라서 흙탕물 유입가능성이 높은 도로에 비노출 배수로를 설치하게 되는 경우 배수로의 효율이 낮아지는 것에 대한 대책이 필요하고, 철저한 관리가 요구된다. 이러한 문제점을 해결하기 위해 비노출 배수로의 채움재를 개선하고 동일실험 수행을 계획 중이며, 비점오염물의 제거효율 또한 검토할 예정이다.

• The Journal of the Acoustical Society of Korea
• /
• v.39 no.2
• /
• pp.105-112
• /
• 2020

An analysis model of noise map is proposed to evaluate and reduce the acoustical noise of power plant and its surroundings. The sound powers of many noise sources are estimated by measuring the sound levels of major equipments in the power plant. The analysis of noise has been made by using ENPro that is a commercial program for environmental noise prediction. The proposed model is verified by comparing the results from noise analysis and measurement at several points of the power plant units 1 through 4, and residential areas. It is shown that noise map simulation using the proposed model has a reliability, since the overall noise level approximates within the error of ±2 dB. Furthermore, through noise analysis, the increasing effect of noise due to newly established units 5 and 6 on residential areas is also analyzed. Consequently, the noise barrier is designed to meet an environmental noise standard and satisfy low cost and safety conditions.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.47 no.1
• /
• pp.112-119
• /
• 2010

This paper defines the probability models for determining the disparity map given stereo images and derives the methods for solving the problem, which is proven to be equivalent to an energy-based stereo matching. Under the assumptions the difference between the pixel on the left image and the corresponding pixel on the right image and the difference between the disparities of the neighboring pixels are exponentially distributed, a recursive approach for estimating the MRF regularizing parameter is proposed. Usually energy-based stereo matching methods are so sensitive to the parameter that it should be carefully determined. The proposed method alternates between estimating the parameter with the intermediate disparity map and estimating the disparity map with the estimated parameter, after computing it with random initial parameter. It is shown that the parameter estimated by the proposed method converges to the optimum and its performance can be improved significantly by adjusting the parameter and modifying the energy term.

• Journal of Korea Port Economic Association
• /
• v.33 no.1
• /
• pp.31-46
• /
• 2017

With an increases in income levels and the establishment of a five-day workweek, the number of passengers using international passenger terminals around the world continues to grow every year. However, previous researches on port sector have focused on cargo, and neglected the study on the passenger attraction strategy of the international passenger terminal. Maximizing passenger attraction strategy of the international passenger terminal requires establishing and operating the port marketing strategy, which reflects port characteristics and the tourism marketing strategy, which reflects the hinterland characteristics in an integrated approach. Therefore, the study presents a marketing mix strategy for Daesan International Passenger Terminal based on existing literatures, and a tourism marketing strategy for Seosan city based on the "6A" factor. Recommendations for the Daesan Port include the grand image improvement strategy of Seosan city, utilization of marine tourism resources and development of various tourism products linked to the neighboring areas.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.21 no.5
• /
• pp.542-548
• /
• 2001

A robust, accurate, broad-band, alternating current sensor using fiber-optics is being developed as a part of optical over current protection relay system. The sensor uses the Faraday effect in optical fiber and polarimetric measurements tc sense electrical current. The current sensing coil consists of a length of twisted optical fiber and Faraday rotator mirror to suppress the linear birefringence effect. Due to its single-ended closed path structure, it can not only be easily installed to the target with great isolation from other fields in the vicinity, but the sensitivity can be increased by using multiple turns. This paper reports on the theoretical backgrounds of the sensor design and the preliminary experimental results.

• Geotechnical Engineering
• /
• v.14 no.5
• /
• pp.235-247
• /
• 1998

The IIA(Inchon International Airport) which will function as the HUB airport in the northeast Asian region in the upcoming 21th century will be located in the reclaimed land with sand dredged in the vicinity of project area between Youngjong and Yongyu islands. The original ground is composed of soft clayey silt (ML) or silty clay (CL). The reclaimed land is classified as being SP-SM and having poor gradation of Cu<3 which resulted in the anticipation for difficulty in compaction (compaction index = 0.6~0.7). This anticipation shedded light on the necessity of performing test compactions for the thickness of 3~5meters of reclaimed land, aiming at the discovery of effective and economical compaction method. Upon the call for the test compaction performance 4 different compaction methods have been selected for trial from the research done on the international and local academic papers, past experience with compaction works, and their written materials. For the precise interparetation of test results, the ground survey and measurements have been performed. The Hydraulic Hammer Compaction has been chosen as the most optimum in accordance withe the test results.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.3 s.258
• /
• pp.344-354
• /
• 2007

The objective of this study is to investigate the effect of arbitrarily located defect around the circular hole in the aircraft structural material such as Al/GFRP laminates and monolithic Al alloy sheet under cyclic bending moment. The fatigue behavior of these materials may be different due to the defect location. Material flaws in the from of pre-existing defects can severely affect the fatigue crack initiation and propagation behavior. The aim of this study is to evaluate effects of relative location of defects around the circular hole in monolithic Al alloy and Al/GFRP laminates under cyclic bending moment. The fatigue behavior i.e., the stress concentration factor($K_t$), the crack initiation life($N_i$), the relationship between crack length(a) and cycles(N), the relationship between crack growth rate(da/dN) and stress intensity factor range(${\Dalta}K$) near a circular hole are considered. Especially, the defects location at ${\theta}_1=0^{\circ}\;and\;{\theta}_2=30^{\circ}$ was strongly effective in stress concentration factor($K_t$) and crack initiation life($N_i$). The test results indicated the features of different fatigue crack propagation behavior and the different growing delamination shape according to each location of defect around the circular hole in Al/GFRP laminates.

• Journal of Korean Society of Forest Science
• /
• v.87 no.3
• /
• pp.415-421
• /
• 1998

The purpose of this study is to ascertain the local residents' attitudes toward adjacent recreation forest development sites. 20 items of residents' attitudes were designed from previous tourism impact studies. For this study, two recreation forest areas were selected. In 1995, a total of two-hundred and four local residents were interviewed in their villages near the two recreation forests. A 5-point Scale was used to record the answers. Most respondents were concerned about two negative impacts of the recreation forests development : small economic gains for the residents and damage to the local environment. There were significant differences in certain socioeconamic characteristics of the respondents. Specially, significant differences were identified between the variables of income or non-income from visitors and residence length. Results indicate that recreation forests development may not be perceived as positive as hoped by the government. Further research needs to be conducted on the impacts of present and projected recreation forest development at the local level.