• 대한공간정보학회지
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• 제18권1호
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• pp.47-53
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• 2010

정확한 하천유량은 하천이 지니고 있는 이수, 치수 및 생태기능이 원활이 유지되기 위해서 가장 중요한 항목이다. 특히 하천의 생태기능은 하천의 환경개선에 있어 매우 중요한 기능이다. 하천의 생태유량에 있어서 하천에 서식하는 생물 및 하천지형에 대한 정확한 정보는 중요한 역할을 한다. 본 논문에서는 유역 및 하천의 지형공간자료를 활용하여 시범적으로 하천의 생태유량을 산정하였다. 하천의 환경복원에 있어서 지형공간자료는 매우 중요한 기초자료로 활용된다.

• 대한의용생체공학회:의공학회지
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• 제7권1호
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• pp.75-79
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• 1986

In this paper, a multigate pulsed doppler system with parallel signal processing which enables the transcutaneous assesment of the blood-flow velocities of five adjacent sample volumes is developed. The outputs of the system are audio signals, velocity curves and velocity profiles of 5 adjacent sample volumes. We have applied to the major superficial arteries and obtained the detailed information about the time dependent blood-flow behavior.

• 한국환경과학회지
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• 제22권2호
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• pp.225-234
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• 2013

The relationship between debris flow and topographical factors is essential for the reliable estimation of soil loss. The objective of this paper is to estimate stability index and soil loss for assessing landsliding risk caused by debris flow. SIMAP and RUSLE are used to estimate stability index and soil loss, respectively. The landsliding risk area estimated by using SIMAP is found to be different from the large land area estimated by RUSLE. It is found that the spatial distribution of soil cover significantly influences landsliding risk area. Results also indicate that stability index and soil loss, estimated by soil cover factor, improve the assessment of landsliding risk.

• 한국수소및신에너지학회논문집
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• 제31권5호
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• pp.480-488
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• 2020

This study was conducted to improve the flow uniformity inside the chip tester through changing the flow path formation according to the inlet and outlet position of chamber. The internal flow and velocity distributions of the modified chamber models (Cases 1-3) were compared with the reference chamber model through three-dimensional Reynolds-averaged Navier-Stokes equations with k-ε turbulence model. The modified chamber models showed the superior flow uniformity characteristics compared to the reference chamber model. To investigate the flow uniformity in the chip tester, the standard deviation of the velocity was defined and compared. Through the internal flow analysis and assesment of the standard deviation, Case 2 among the test cases including the reference model showed the best flow uniformity generally.

• 대한한방내과학회지
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• 제21권5호
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• pp.805-811
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• 2000

Objectives : To determine the effects on blood flow of vertebrobasal vascular system in cerebral infarction, Methods : We altered 33 normal patients and 12 patients who were diagnosed cerebral infarction on Rt. middle cerebral artery(MCA) region and 8 patients who were diagnosed cerebral infarction on Lt, MCA region, and measured the mean velocity, systolic to diastolic rate(SD rate), asymmetrical index(A/I) by TCD. Results : The mean velocity of posterior cerebral artery(PCA), vertebral artery was increased in same direction as infarcted site and the mean velocity of basal artery was more increased than control, and the SD rate of PCA, vertebral artery, basal artery was larger than control. The A/l of PCA, vertebral artery was revealed that mean velocity of vertebrobasal vascular system is increase the same direction as infarcted area. Conclusion : TCD examination within 7 days(acute stage) after stroke can help to predict the infarcted direction.

• 조명전기설비학회논문지
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• 제20권9호
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• pp.61-69
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• 2006

The tensile strength of an overhead transmission line's conductor in response to an aging is being assessed in this paper. It is our view that, the decrement in the conductor's tensile strength is a key index that can be used to determine a conductor's end of life and a current limits. This paper describes a probabilistic method of assessing this index for main transmission lines which are responsible for the north bound power flow in the Seoul metropolitan area. Such an assessment can be a useful guide for economic system operation.

• 전기학회논문지
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• 제58권12호
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• pp.2311-2315
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• 2009

This paper presents a method to apply energy margin for assesment of total transfer capability (TTC). In order to calculate energy margin, two values of the transient energy function have to be computed. The first value is transient energy that is the sum of kinetic and potential energy at the end of fault. The second is critical energy that is potential energy at controlling UEP(Unstable Equilibrium Point). It is seen that TTC level is determined by not only bus voltage magnitudes and line thermal limits but also transient stability. TTC assessment is compared by the repeated power flow(RPF) method and optimization method.

• 환경영향평가
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• 제19권5호
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• pp.511-525
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• 2010

Understanding of the hydraulics of flow over vegetation is very important to support the management of fluvial processes. The objective of this study is to assess the effects of hydraulic influence by tree planting in a compound channel with vegetated floodplain. This study analyzes the influence of tree planting on hydraulic features in Young-river in Munkyung city using HEC-RAS and RMA-2 model. The study results showed that there is a rise in water surface elevation and decrease in velocity near vegetated area. It is also ascertained that only negligible effects was seen within the feasible range of freeboard for the existing levees. However, as hydraulic features can vary depending on the aspect of flood inundation during each flood period, it is necessary to accumulate data through continuous data collecting.

• 한국항만학회지
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• 제12권2호
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• pp.303-312
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• 1998

It is necessary to quantitatively asses the influence of tidal currents to analysis the coastal current patterns before or after constructing offshore structures like as breakwaters. This assesment can be made through the use of simulation models designed to reproduce the water movements of the area. And it is very important to predict a phenomenon of pollutant dispersion in the area. In this study, in order to predict the changes of sea water quality for the port development plan, Ilgwang harbour, located at the east coast of Pusan, the numerical computations were carried out. The flow patterns were investigated before and after the development of the harbour bay and coastal area connected on it. The computational models are an extension of earlier work on the flow which used the ADI Method (Alternating Direction Implicit Method) in appling to Osaka Bay by KANEKO et al. The transport of pollutant constituents depends upon the currental characteristics of the water-transporting medium. In the currental flow model, water velocities and water levels are computed throughout the regions of it. These value are then used in the mass-balance equation to obtain the pollutant-constituent transport. As a result of this research, the present water quality of Ilgwang harbour and the coastal areas connected on it was proved out some good condition. The changes of sea water quality due to the port development plan of the Ilgwang habour bay and the coastal area were not large compared with the present condition, but it will be likely able to get worse by increasing the semi-enclosed areas in the harbour bay. In order to improve the water quality of the area after development, the method to activate tidal exchange in the area can be needed, as a mitigation technique.

• 자원리싸이클링
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• 제14권2호
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• pp.43-55
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• 2005

세계의 인구증가와 경제성장에 따라 천연자원 특히 전략금속의 수요가 급격히 증가하고 있다. 국가가 보유하고 있는 자원의 양은 천연자원 뿐 아니라 재활용을 통하여 얻을 수 있는 폐자원을 함께 포함해야 한다. 본 연구에서는 전략금속의 안정적 확보와 폐자원의 효율적 재활용을 위하여 코발트의 국내외 사용현황 등을 조사하였으며 아울러 미국 내에서의 코발트 물질흐름에 대한 자료를 정리하였다. 그 결과 미국에서는 2003년도에 약 8,000톤의 코발트가 사용되었으며 원료로 재사용된 스크랩의 양은 총사용량의 28%인 2,200톤이었다. 미국의 경우 초합금과 촉매의 재활용은 잘 이루어지고 있으나 자석류와 초경합금의 경우 재활용율이 다소 낮음을 알 수 있었다.