• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.23-27
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• 2011

Due to the rapid development of construction technology with effective land utilization in this nation, many tunnels were and are being built across the country. However, the smoke and the heat generated from tunnel fire are the most important critical factors which may results in both massive personal injury and property damage, especially, due to the closed surrounding of the tunnel. Considering this particular nature of the tunnels, this study aims to install a fire detection system using an optic fiber cable to measure the temperature changes, compare, and analyze the resulted values with the times of temperature changes of the sensor by performing fire simulations under the same condition as a real fire test. From the results, it has been found that the temperature sensor detects a fire occurrence and generates an alarm within one minute after ignition for both a real fire test and a fire simulation alike, and also that the characteristics of temperature changes of the sensor has close relations with the speeds of the currents inside the tunnel. In addition, considering the tunnel fires can affect the evacuation efficiency and the fire extinguishing activities of the fire brigade inside the tunnel, the temperature sensor must be able to search and find the locations and directions of the fires correctly.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.514-521
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• 2018

COSPAS-SARSAT 406 MHz emergency beacons include ELTs for aviation, EPIRBs for maritime, and PLBs for individuals in distress. They are used to sending messages encoded on 406 MHzdistress frequency and sending alertsfor search and rescue in distress. C/S T.001 and T.018 are COSPAS-SARSAT technical documents. They include basic technical information needed for developing beacons, howmessages are constructed, and test methods for type approval. COSPAS-SARSAT systems that use existing low earth orbit (LEO) and geostationary earth orbit (GEO) satellites do not have a return link service (RLS). So, the survivors could not confirm whether the distress signal was sending or not. However, a new medium earth orbit (MEO)satellite system has been added to thissystem, allowing confirmation through the RLS function. This paper analyzed C/S T.001 and T.018 needed to develop navigation structuresthat incorporated improved PLB of 406 MHz, a homing signal generator of 121.5 MHz, and a VHF AM transmitter for aviation of 243 MHz.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.352-352
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• 2017

2014~2015년에 걸쳐 발생한 가뭄으로 농업용수뿐만 아니라 생공용수 공급 측면에서도 어려움이 발생하였다. 기후변화 등의 요인으로 이러한 상황이 향후에도 발생할 것으로 예상됨에 따라 가뭄현황 및 전망 정보 생산을 통한 가뭄 대비의 필요성이 커지고 있다. 본 연구에서는 2016년 기상 및 수문상황을 분석하고, 생공용수 부문 가뭄예경보를 위해 활용중인 K-water 가뭄정보분석시스템을 통해 생산된 2016년 가뭄 정보를 분석하였다. 2016년 전국 강수량은 1966~2015년 평균 대비 92.2%에 해당하는 강수량을 기록하였다. 지역적으로는 중부지방은 대체로 평균에 미치지 못하는 강수량을, 중부이남 지역은 평균 이상의 강수량을 보였다. 경기도 남부 지역을 중심으로 강원도 일부 지역과 충남 서부 지역의 강수량 부족이 심했던 것으로 나타났다. 강수에 의한 2016년 자연유출량을 중권역 단위로 산정한 결과 1967~2015년 평균 대비 91% 수준의 유출량이 발생된 것으로 추정되었다. 이는 평균적으로 강수량이 많은 6월과 8월에 강수가 적었기 때문인 것으로 보인다. 특히 6개 주요 유역 중 유역면적이 가장 넓은 한강 유역은 낙동강 유역보다 약 6억톤 적은 값을 보였다. 생공용수 공급의 주요 수원인 다목적댐의 총저수량은 2014~2015년의 극심한 가뭄으로 2016년 1월 1일에 예년보다 10억톤 가량 적었다. 하지만 봄철에 예년보다 다소 많은 강수가 발생하고, 홍수기 초에도 많은 강수가 발생하여 저수상황이 다소 개선되었다. 8월의 적은 강수량으로 저수량이 지속적으로 하락하였으나 9, 10월에 걸쳐 태풍에 의한 많은 강수로 예년 대비 104.4% 수준의 저수량을 확보하였다. K-water 가뭄정보분석시스템을 통해 매월 초 생공용수 관련 가뭄현황 및 1 3개월 전망을 분석하였다. 매월 초 가뭄예경보를 위해 분석된 가뭄현황에서는 3월초, 9월초, 10월초, 11월초에 보령댐을 수원으로 하는 충남 서부 8개 시 군에서 가뭄상황 '주의'가 발생했고, 6월초 강원도 강릉시 상수원인 오봉저수지 저수량이 평년보다 낮아 가뭄상황 '주의'가 발생하였다. 언론보도를 바탕으로한 가뭄 발생 상황을 가뭄정보분석시스템을 통해 판단한 가뭄 상황과 비교한 결과 가뭄정보분석 시스템에 의한 가뭄인지가 신뢰할 수 있는 수준인 것으로 판단된다. 또한 가뭄정보분석시스템에 의한 1 3개월 가뭄전망과 1 3개월 후 실제 가뭄 상황을 비교한 결과 전망 정확도가 대체로 높아 가뭄정보분석시스템에 의한 가뭄전망이 신뢰할 만한 수준인 것으로 판단된다.

• Journal of the Korea Society for Simulation
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• v.31 no.3
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• pp.45-54
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• 2022

This paper is about designing and implementing the simulation training equipment (simulator) for the CBRN Reconnaissance Vehicle-II (armor type). The simulation training equipment (simulator) is a military training equipment in a virtual environment that analyzes the training using various CBRN equipment according to the CBRN situation and make a professional report. The controller or training instructor can construct a scenario using the instructor control system for a possible CBRN situation, spread the situation, and observe the process of the trainee performing the propagated situation appropriately. All process can be monitored and analyzed by the system, and it can be recorded, so it is also used for AAR (After Action Review). To implement CBRN situation training in a virtual environment, instructor control (IOS), host (HOS), video (IGS), input/output device (IOC), and sound (ACS) were implemented, a long-range chemical automatic detector (LCA), a combined chemical detector (CAD), a control (MCC) and an operation (OCC) computer were developed as simulators. In this paper, the design and development of simulation training equipment for CBRN Reconnaissance Vehicle-II (armor type) was conducted, and the performance was verified through integrated tests and acceptance tests.

• Journal of Korea Water Resources Association
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• v.48 no.5
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• pp.409-423
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• 2015

In this study the very short-term rainfall forecasting and storm water forecasting using the weather radar data were implemented in an urban stream basin. As forecasting time increasing, the very short-term rainfall forecasting results show that the correlation coefficient was decreased and the root mean square error was increased and then the forecasting model accuracy was decreased. However, as a result of the correlation coefficient up to 60-minute forecasting time is maintained 0.5 or higher was obtained. As a result of storm water forecasting in an urban area, the reduction in peak flow and outflow volume with increasing forecasting time occurs, the peak time was analyzed that relatively matched. In the application of storm water forecasting by radar rainfall forecast, the errors has occurred that we determined some of the external factors. In the future, we believed to be necessary to perform that the continuous algorithm improvement such as simulation of rapid generation and disappearance phenomenon by precipitation echo, the improvement of extreme rainfall forecasting in urban areas, and the rainfall-runoff model parameter optimizations. The results of this study, not only urban stream basin, but also we obtained the observed data, and expand the real-time flood alarm system over the ungaged basins. In addition, it is possible to take advantage of development of as multi-sensor based very short-term rainfall forecasting technology.

• Korean journal of communication and information
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• v.43
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• pp.247-281
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• 2008

The purpose of this article is to re-examine the issue of Chobo's origin, which has not been clearly determinated thus far. Also, the research investigates Chobo's name, time point of discontinuance, character of the article on disaster, and civil-printed incident of Chobo during King Sunjo. As an internal bulletin, handwritten Chobo began to come out at the end of 15th century, roughly King Sungjong period of Chosun Dynasty. Systematically developed in the period of King Jungjong, it had continuously been released until November, 1907 when fairly organized and competitive commercial daily newspapers were published and when the office of secretary named Biseogam was abolished. Because handwritten Chobo was exclusive and narrow in its communication nature and difficult to read it's fast handwritten Nancho calligraphic style, in August, 1577 (10th year of King Sunjo) a few civilian in Seoul obtained a permission from authorities (Uijungboo and Sahunboo) published a wooden type printed Chobo. Unfortunately, privately printed Chobo was forced to cease in 3 month because of King Sunjo's oppressive measure. However, considering it was published for a profit by civilian and used the world's first type printing, it is highly probable that Chobo seems to be the world’s first type printing commercial daily newspaper.

• Journal of Korean Society of Transportation
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• v.23 no.4 s.82
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• pp.17-28
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• 2005

About 91.1% of Railway-Highway Crossings (RHC) in Korea use a Constant Distance Warning System(CDWS), while about 8.9% use a Constant Warning Time System(CWTS). The CDWS does not recognize speed differences of approaching trains and provides only waiting times to vehicles and pedestrians based on the highest speed of approaching trains. Under the CDWS, therefore, low speed trains provide unnecessary waiting times at crossings which often generates complains to vehicle drivers and pedestrians and may cause wrong decisions to pass the crossings. The objective of this research is to improve the safety of the RHC by developing accurate a CWTS. In this research a train speed and location detection system was developed with ultra sonic detectors. Locations of the detectors was decided based on the highest speed and the minimum warning time of Saemaul of 160 km/h. To validate the algorithms of the newly developed systems the lab tests were conducted. The results show that the train detection system provides accurate locations of trains and the maximum error between real speeds of trains and those of the system was 0.07m/s.

• Fire Science and Engineering
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• v.31 no.5
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• pp.44-52
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• 2017

This paper is based on a study of the response characteristics of photoelectric type smoke detector chambers according to dust color. Due to an amendment to the Fire Safety Codes to automatic fire alarm systems and visual alarm device, the installation of indoor smoke detectors has become mandatory, but in Korea there is still insufficient research on the non-operation or false alarms that could arise in indoor environments by indoor dust and other environmental conditions etc. In light of this, for this study, research was conducted on the indoor adaptability of smoke detector under various colors of fiber dust that were judged to occur most frequently in among the common indoor dust, photoelectric smoke detector with the lattice-type smoke detection chamber that the smoke detector which is most popular in the country was used, and four colors of fiber dust (brown, white, gray and black) were used the test dusts for carrying out dust and sensitivity testing. Also, the voltage of the photocell part of the smoke chamber was measured, and the scattering phenomenon in the chamber was observed. The result of the testing showed that all four dust types were suitable for dust and sensitivity testing under conditions of pollution A. Yet, there were occasions, at pollution B or C, where the brown, white and gray dust would cause fail alarm during operation testing. And black dust was confirmed to cause non-operation during operation testing. In the case of brown and white dust, the voltage measurement result of the photocell part of the smoke chamber confirmed that the voltage increases as the pollution level increases, and in the case of gray and black dust, the voltage decreases.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.400-402
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• 2019

The electric point machine, which is used for the control of the turnout used to change the track of the train, is very important in the railway system. Various wired and wireless real-time monitoring systems are used to check the status of the point machine, but there is a possibility of malfunction due to sensor or network error. In this paper, a redundant monitoring system was designed that incorporates the point machine monitoring system and the CCTV camera control system to double check the operation of the point machine. In the point machine monitoring system, the operating state of the railway converter is monitored, alarmed and transmitted over the network. The CCTV camera control system, which received this information, was required to record the status of the turnout and the point machine in question and send it to the administrator. The manager of the railway line can check the conversion status of the railway through the monitoring screen for the railway line switcher first, and then confirm the switching status directly through the CCTV camera image, thereby improving the reliability of the point machine operation. It will also enable the safe and efficient operation of personnel for management. It is expected to contribute to preventing a derailment caused by a malfunction of the point machine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.87-96
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• 2020

To use a hydraulic structure effectively, the velocity of a river should be known in detail. In reality, velocity measurements are not conducted sufficiently because of their high cost. The formulae to yield the flux and velocity of the river are commonly called the Manning and Chezy formulae, which are empirical equations applied to uniform flow. This study is based on Chiu (1987)'s paper using entropy theory to solve the limits of the existing velocity formula and distribution and suggests the velocity and distance formula derived from information entropy. The data of a channel having records of a spot's velocity was used to verify the derived formula's utility and showed R2 values of distance and velocity of 0.9993 and 0.8051~0.9483, respectively. The travel distance and velocity of a moving spot following the streamflow were calculated using some flow information, which solves the difficulty in frequent flood measurements when it is needed. This can be used to make a longitudinal section of a river composed of a horizontal distance and elevation. Moreover, GIS makes it possible to obtain accurate information, such as the characteristics of a river. The connection with flow information and GIS model can be used as alarming and expecting flood systems.