• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.34-34
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• 2022

우리나라의 하천은 그 중요도와 규모에 따라 국가·지방·소하천 및 세천 등으로 분류하고 있다. 우리나라 하천 관리는 주로 국가 지방하천을 중심으로 이루어지고 있다. 특히 수리량 계측에 있어서 대부분의 수위 유량 관측시설이 국가 지방하천에 위치해 있으며, 소하천에 대한 관측은 거의 이루어 지지 않고 있다. 이로 인해 소하천 설계기준의 홍수량 산정 공식은 국내 중규모 이상 하천의 경험식이나 외국의 소하천 경험식에 기반한 매개변수를 따르고 있어, 국내 소하천의 특성을 반영하지 못하고 있다. 국립재난안전연구원에서는 국내 소하천 특성에 적합한 설계기준 개발 및 홍수량 산정을 위해 소하천 자동유량계측기술을 개발하고, 전국 소하천의 10%(2,230개소)에 설치·운영하는 것을 목표로 행정안전부 및 지자체와 협력하여 확대 구축을 추진 중이다. 소하천은 유로연장이 짧고 유역면적이 크지 않아 도달시간이 짧은 것이 특징으로, 강우-유량 노모그래프를 사용하여 소하천 홍수 예·경보를 위한 홍수량 산정이 가능하다. 강우-유량 관계는 선행강우에 따른 토양의 포화상태와 강우 발생 시점의 기저유량 등에 영향을 많이 받는다. 본 연구에서는 자동유량계측기술 설치 시범소하천 5개소의 계측데이터를 사용하여 선행강우를 고려한 강우-유량 노모그래프를 개발하였다. 또한, 뉴로-퍼지 기법과 회귀분석을 사용한 홍수량 예측결과와 비교 연구를 수행하였다.

• Water for future
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• v.29 no.2
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• pp.209-219
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• 1996

The existing gate operation rule of Paldang hydroelectric plant has been used since the construction of the dam in 1973 except partial modification due to the construction of Chungju multipurpose dam in 1985. The water level near the downstream of Paldang dam has been lowered about 3 m because of the channel maintenance of Han River development project. Thus, the discharge estimation formula based on the submerged orifice type spillway has to be re-evaluated by considering various patterns of the gate operation rules and lowered channel bed. In this study, three types of gate openings were tested to select the proper gate operation rules through the hydraulic model test for various discharges and opening heights. Also, the numerical analysis has been performed to simulate the flow patterns of downstream. As a result, the gate operation rule, which opens 5 gates each time from the left side, was selected as the proper gate operation rule of Paldang dam.

• Fire Science and Engineering
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• v.31 no.1
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• pp.98-107
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• 2017

This study examined an effective way of measuring the evacuation performance in buildings, which are applied to a double skin facade through an evaluation of the escape safety. Buildings with a double skin facade appeared to have a faster combustion expansion speed for the upper floor if a fire occurs. Moreover, a double skin facade is more difficult to escape safely than a general building construction because of the limited design standards. Accordingly, this study suggested virtual modeling including single emergency stairs and alarm systems considering the risk in each structure of buildings. These results showed that box-type double skin, corridor access type, shaft-box type, and multistory facade systems showed a 26.4%, 29.1%, 23.4%, and 26.3% increase in evacuation performance, respectively, as well as securing the safety of occupants.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.6
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• pp.917-922
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• 2013

In this paper, we propose a smoke detection system in order to detect a fire in a wide space, such as tunnel, airports using infra-red and visible laser. The proposed smoke detection system is composed of infra-red laser transmitter and receiver, visible laser and Zigbee wireless communication network. A visible laser is used to match transmitter and receiver and Zigbee network is utilized to propagate warnings of fire. If smoke is appeared between transmitter and receiver, received signals are decreased and it can be considered as occurring smoke. As IR laser transmitter and receiver are separated by long distance, it is difficult to match due to large variations caused by small change of direction. In this paper, it is proposed to match effectively using visible laser. When smoke is detected, warning informations are propagated by Zigbee network in the developed smoke detection system.

• Journal of the Korean Institute of Gas
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• v.12 no.4
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• pp.1-7
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• 2008

In the last five years, 36 people died and 79 were wounded because of carbon monoxide poisoning accident. A CO poisoning accident is higher than any other gas accident in the rate of deaths/incidents. Most of these CO poisoning accidents were caused by defective exhaust tube in the old gas boiler and multi-use facility. In this study, the spread mechanism of CO gas released from leakage hole of exhaust tube was analyzed by concentration measuring test. A CO gas leaked form exhaust tube in a building was the highest concentrated near the ceiling. CO alarm sets installation test confirmed that the alarm sets near the ceiling operated first, and the bottom and middle sets operated after $30{\sim}40$ minutes. Through these experiments, the reasonable installation location of CO alarm was made certain and suggested.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.379-388
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• 2015

In the end of 1990's, future free flight technology had been developed and tested in America and government established the plan for free flight until 2017. Aircraft separation assurance must be secured essentially to avoid collision between aircrafts before Free Flight comes true. Now, Civil aircraft has rules about avoidance activity with traffic collision avoidance system (TCAS) but it can't apply to light aircraft. So there is a need about alternative method to apply light-aircraft because it has space and price problem to use TCAS. In this paper, TCAS algorithm has been modified and verified by simulating with LABVIEW program under ADS-B condition to get miniaturization and weight lighting cheaply. By simulating, collision alert algorithm is analyzed and verified with collision situation proposed by ICAO, and 100% checked for performing the alert announciation on all cases by TCAS standards.

• Journal of Korean Society on Water Environment
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• v.33 no.2
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• pp.130-139
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• 2017

With the need to evaluate accuracy of real-time measurement of cyanobacterial fluorescence to determine cyanobacterial blooms, this research examined 357 paired data (2013-2016) comprising both microscopic toxic cyanobacterial cell counts and concurrent real-time cyanobacterial concentrations at 2 sites (YS1 and YS2) in Yeongsan river. The increase in real-time cyanobacterial concentration was closely associated with the exceedance of 5,000 cyanobacterial cells/ml (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.03-1.12) and 10,000 cells/ml (OR 1.08, 95% CI 1.04-1.12) at YS2 site. The area under the receiver operating characteristic (ROC) curve for the real-time cyanobacterial measurement at the YS2 site was 0.93, which indicates the measurement provides a high accurate detection of cyanobacterial blooms. On the ROC curve, the early alert levels of real-time cyanobacteria ranging $16-23{\mu}g$ chl-a/L would produce acceptable sensitivity of 79% and specificities greater than 90%. The real-time fluorescence measurement was found to be an accurate indicator of cyanobacteria and can serve as a tool for detecting toxic cyanobacterial bloom events in Youngsan river.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.352-356
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• 2008

가뭄관리에서 가장 중요한 요소는 1) 강수량, 지표수, 지하수, 댐수, 토양수분 등 물 공급량의 시 공간적 모니터링과 2) 이용가능한 물 공급량 약화 정도에 따라 적시적소에 물 이용자가 취해야할 행동요령을 제시하는 것이다. 가뭄지수는 가뭄관리에서 종합적인 물 공급량 정보를 하나의 수치로 정량화하여 가용 수자원의 악화정도를 나타내어 가뭄경보의 기준으로 활용된다. 현재까지 개발된 대표적인 가뭄지수들은 PDSI(Palmer Drought Severity Index), SPI(Standardized Precipitation Index), SWSI(Surface Water Supply Index) 등이 있다. PDSI는 여러 가지 제한점을 가지고 있지만 가뭄지수 개발의 시발점이 되었다는 점에서 전세계적으로 이용하고 있고 국내에서도 기상청의 공식적인 가뭄지수로 발표되고 있다. PDSI는 복잡한 물수지 모형에 의해 산정되며, 이용되는 매개변수는 지역의 기후상황, 보정자료기간 등에 민감하게 작용하고 있으나 이들에 대한 국내기후 환경에서의 평가가 선행되어 있지 않고 있다. PDSI는 가뭄과 습윤 기간의 시작과 종료 시점을 확률적으로 산정하여 이를 기반으로 가뭄경보에 활용하고 있다. 또한, 이들 확률은 기상학적 가뭄상황을 나타내는 PDSI에 후행하는 하천유출, 저수지 수위, 지하수 등의 수문학적 가뭄을 표현하는 PHDI(Palmer Hydrological Drought Index)를 산정하는 데 이용된다. Z-지수 역시 PDSI에서 얻을 수 있는 가뭄지수로 단기간의 가뭄특성에 의한 농업가뭄을 표현하는 데 적합한 지수로 알려져 있다. 본 연구에서는 PDSI의 제한점들을 살펴보고 우리나라의 기후상황, 자료보정기간 등에 따른 PDSI의 제매개변수들을 재산정하여 계산된 PDSI의 변동성을 검토한 후 이를 Palmer(1965)가 제시한 PDSI 산정식과 비교 평가하였다. 또한 가뭄의 시작과 종료 확률 개념에 의하여 산정된 PDSI를 기상청에서 제공하고 있는 PDSI와 비교 분석하여 개선점을 도출하였다.

• Convergence Security Journal
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• v.6 no.4
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• pp.67-73
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• 2006

The method which research a standardization from real time cyber threat is finding the suspicious indication above the attack against cyber space include internet worm, virus and hacking using analysis the event of each security system through correlation with the critical point, and draft a general standardization plan through statistical analysis of this evaluation result. It means that becomes the basis which constructs the effective cyber attack response system. Especially at the time of security accident occurrence, It overcomes the problem of existing security system through a definition of the event of security system and traffic volume and a concretize of database input method, and propose the standardization plan which is the cornerstone real time response and early warning system. a general standardization plan of this paper summarizes that put out of threat index, threat rating through adding this index and the package of early warning process, output a basis of cyber threat index calculation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.9
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• pp.821-827
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• 2015

Electromagnetic waves which are emitted from the Sun due to solar flare explosion can cause failures in HF radio communications in the day-side area of the Earth, that is so-call as Radio Blackouts. The international scale representing the severity of the Radio Blackouts is determined by the solar X-ray flux which is measured by United States Geostationary Operational Environmental Satellite. However, the scale is not always applicable to HF communication users in the different area on the Earth, because the HF communication effects depend not only on the X-ray strength but also on the subsolar point location. To solve this problem, we developed a HF radio spectrum monitoring system utilizing a spectrum analyzer. This system conducts a real-time measure of the HF spectrum, and automatically calculates signal to noise ratios and the occurrences of the HF blackouts as comparing with the interference level which is described from the ITU recommendation.