• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.177-188
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• 2019

The purpose of the optimization of the installation of supply/exhaust ports for tunnels with transverse ventilation system is to supply fresh air from outside to inside of tunnels uniformly and exhaust pollutant from tunnels properly for creating safe and clean environment for tunnel users. For this purpose, a ventilation port area optimization program was developed to obtain a uniform supply or exhaust air volume inside a great depth double deck tunnel with transverse ventilation system. In order to area optimize the developed port sizing program, the wind velocity was measured in the duct of the currently operated tunnel with semi-transverse ventilation. Also 3D cfd was performed on the same tunnel and cfd results were compared to the measured value. As a result, the error rate between the predicted value from the program and measured value was 6.72%, while the error rate between the predicted value from the program and 3D cfd analysis value was 4.86%. Both of comparison results show less than 10% of error rate. Thus It is expected that supply/exhaust port optimization design of transverse ventilation tunnel can be possible with using this large exhaust port area optimization program.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.661-667
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• 2006

In this study, an experiment of sewage sludge dewatering is carried by using electrokinetic method, and the electrokinetic dewatering efficiency of digested sludge is analyzed. Digested sludge without coagulants is selected and gravitational and pressing dewatering methods are applied in combination with electro-osmotic and electro-osmotic pulse technology. After the test of digested sludge, dewatering test of thickened sludge is carried to evaluate the electrokinetic dewatering feasibility of thickened sludge. Under the condition of constantly applied voltage, however, electrical resistance increases with decreasing of water content so that dewatering rate decreases with time. To reduce such a hindrance caused by constantly applied voltage, electro-osmotic pulse technology which is considered to reduce the difference of water content with height, is applied. For the application of electro-osmotic pulse, the dewatered flow rate and the dewatered volume became more increasing from the middle of the dewatering process than that of continuous voltage. Through the test of thickened sludge, electro-osmotic dewatering combined with gravitational and expression also showed high dewatering rate, which proved the possibility of using electrokinetic dewatering.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.275-279
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• 2003

2002년 현재 서울시는 99.99%에 이르는 높은 상수도 보급율에 비하여 유수율은 선진국의 수준에 이르지 못하고 있는 실정이다. 이는 정수장에서 배수지까지 연결되는 송수관과 배수지에서 각 가정으로 보낼 때 사용되는 배급수관에서의 누수 발생이 주 원인이며, 이는 곧 체계적인 관망 설계 및 운영이 미흡하기 때문인 것으로 지적되고 있다. 상수관로의 누수현상을 해결하고 효과적인 관리를 위한 근본적인 대책으로 노후관로의 교체가 필요하게 된다. 또한 노후관망 교체 등 유사시에 안정적인 상수의 공급을 위해 배수지간을 연결하는 대안 관로를 둘 필요가 있으며, 이러한 관망의 경로를 적절하게 설계해야 하는 것도 주요한 상수 공급 문제 중의 하나이다. 2000년 서울시 수도 정비 기본 계획의 관망 정비계획에 따르면 배수관리를 원활하게 하고 누수를 효율적으로 탐지·방지하기 위한 가장 이상적인 관망구성은 배수지 중심의 블록 시스템으로 보고 있다. 이와 같은 문제점들을 기반으로 하여, 본 연구는 GIS를 이용하여 효과적으로 노후관망을 관리하고, 대안 관망경로를 구축하는 시스템을 제안하였다. 본 연구에서는 배수지를 중심으로 한 블록 단위기반의 관망 노후도를 체계적으로 분석하는 시스템과 함께, 유사시를 대비한 최단/최적의 대안 경로를 산출하는 시스템을 구현하여 이를 서울 일부지역에 적용하여 그 유용성을 점검하였다. 상수도 관망의 설치 계획은 상수도 시설의 규모의 확장과 시설계량에 있어 대규모의 비용과 시간이 요구되는 특성을 가지고 있기 때문에 시설투자에 있어 정확한 예측과 분석을 통해 이루어져야 한다. 본 연구에서는 이러한 예측과 분석의 의사결정을 지원할 수 있는 상수도 배수 블록 노후도 관리 시스템과 최단/최적 연결 경로 산출 시스템을 구현해 봄으로써 다음과 같은 결론을 얻었다. 1. 상수도의 관망 노후도의 분석을 화면상에서 다양한 요소별로 하게 함으로써 넓은 공간에서의 관망의 관리를 효과적으로 할 수 있게 해준다. 2. 또한 이와 함께 대안 관망들을 사용자가 직접 대화식으로 빠르게 설계하고 이들의 경로와 공사비용 등을 산출해 봄으로써, 후보 최적 경로들을 공간적, 정량적으로 비교하는 것이 용이하다.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.4
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• pp.1-15
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• 2003

Recently, urban information system(UIS) has been developed and utilized by local governments in Korea and has become a key means of urban informatization of local governments. When UIS is conducted only for FM oriented internal utilization regardless of its cost-efficiency, however, its cost-benefit structure could be distorted seriously. The study utilizes benefit cost analysis technique and applied the technique to a model case of Chungju UIS selected by National GIS team. Chungju City developed its GIS for the management of roads and urban planning in 1993. At its beginning, the system was an efficient model with relatively strong cost-benefit structure and could produce positive net benefit 10 years' after its construction. When the city began to develop its facility management with the financial assistance from central government in 1998, however, its cost-benefit structure became distorted. As a result, it is delayed for the UIS to produce positive net benefit until the year of 2015. Using benefit cost ratio, discount rate and Mobile GIS, the study also conducts a sensitivity analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3570-3576
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• 2013

This paper calculated advanced sewage treatment efficiency and reduction pollution loads to estimation contribution ratio of for community sewerage in Hongcheon-gun County. The A2/O and SBR methods showed overall high treatment efficiency of 95% and 94% respectively, and SS was 80%. On the other hand, T-N and T-P showed relatively low processing efficiency of 56% and 60% respectively, but it was observed that SS showed high 96% in the MBR method. Next, by the result of yearly water change analysis on water quality of Hongcheon River which is the discharge river of community sewerage, it was observed that water quality was greatly deteriorated by COD, T-N and T-P. However, installation and operation of community sewerage showed high pollution load reduction in general water quality item by more than 80%, and in T-N and T-P by 58% and 68% respectively. It is expected that community sewerage will greatly contribute in water quality improvement of Hongcheon River.

• Journal of Korean Society of Transportation
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• v.29 no.4
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• pp.17-28
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• 2011

This study proposed a speed management strategy for the enhancement of traffic safety on freeways. A novel feature of the proposed strategy is to provide desirable speed information to individual vehicles. A microscopic traffic simulator, VISSIM, was used for the performance evaluation. Vehicle trajectory data were used to evaluate the various speed management scenarios including the different levels of proportions of heavy vehicles. The proposed speed management strategy would be a useful precursor for developing an effective traffic control and operations system to prevent traffic accidents on freeways.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.1
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• pp.9-12
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• 2018

The use of underground transmission power lines is expanding for the beauty and convenience of the near city. However, there is a lack of research on the losses from underground transmission power lines, especially those that support three-phase cables operating 24 hours a day. Since the supporting the cable is made of a material having a conductivity and a magnetic permeability, an eddy current and a hysteresis loss are generated due to a magnetic field caused by a current flowing in the cable. Losses occurring in this case adversely affect the power energy transfer efficiency, so research on loss is necessary. Therefore, in this paper, we analyzed the eddy currents and hysteresis losses that occur in a supporting a cable through three - dimensional finite element analysis.

• KSBB Journal
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• v.15 no.3
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• pp.238-242
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• 2000

A fusion protein of human interleukin-2(hiL-2) and glucagon which was expressed in Escherichia coli. was digested with enterokinase for recovery of hIL-2 from the fused protein. To obtain hIL-2 of optimum recovery hydrolysis reaction were performed under various conditions of urea additives and reaction time. hIL-2 was finally purified by RP-HPLC(reversed phase-HPLC) to remove cleaved G3 fusion partner and residual uncleaved G3-IL-2 HIL-2 was eluted in a single peak at 100% acetonitrile at 28 min. Optimum urea concentration was found to be 0.5 M and 24 h reaction time was sufficient without any additive such as CaCl2 and Tween-20.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.93-104
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• 2002

The purpose of this study was to develop a improved high-order continuum model among macroscopic traffic flow models. This study was mainly performed for uninterrupted flow. In the first step, the proposed model described traffic flow at dropped lane. (no exits) It was possible to describe the traffic flow during short-term considering lane change. The proposed model was based on Payne's model. Our model was newly applied to uninterrupted traffic flow in consideration of geometry condition and driver behavior. It is possible to establish efficient control strategies, simulation and assess the effects of geometric improvements using this model. This model was simulated with field data for the actual adaption. The results of the model tests, traffic volume and density is suitably represented. we think that the results in the article can be led to predicting the situation in the near future.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.1097-1107
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• 2003

The DAWAST model was originally developed to consider the variation of water storage in the unsaturated soil zone and it is a conceptual lumped model. Return flows from agricultural, domestic and industrial water were included to the original result of model simulation to calibrate model parameters of watershed runoff. Agricultural water demand was estimated only in paddy fields supposing that return flow responded at stream was originated from paddy fields. Domestic and industrial water demand was estimated by average daily water demand multiplied monthly variation coefficient. Daily inflow to the Daechung multipurpose dam was applied to verify the DAWAST model considered return flows. On annual average from 1983 to 2001, inflows were simulated to 652.5 mm with return flows considered, which was approached more closer to observed inflow of 667.3 mm, compared with case of 606.8 mm with return flows not considered.