• Fire Science and Engineering
• /
• v.15 no.1
• /
• pp.23-33
• /
• 2001

The utility tunnels are the important facility as a mainstay of country because of the latest communication developments. However, the utilities tunnel is difficult to deal with in case of a fire accident. When a cable burns, the black smoke containing poisonous gas will be reduced. This black smoke goes into the tunnel, and makes it difficult to extinguish the fire. Therefore, when there was a fire in the utility tunnel, the central nerves of the country had been paralyzed, such as property damage, communication interruption, in addition to inconvenience for people. This paper is based on the fire occurred in the past, and reenacting the fire by making the real utilities tunnel model. The aim of this paper is the scientific analysis of the character image of the fire, and the verification of each fire protection system whether it works well after process of setting up a fire protection system in the utilities tunnel at a constant temperature. The fire experiment was equipped with the linear heat detector, the fire door, the connection water spray system and the ventilation system in the utilities tunnel. Fixed portion of an electric power supply cable was coated with a fire retardant coating, and a heating tube was covered with a fireproof. The result showed that the highest temperature was $932^{\circ}c$ and the linear heat detector was working at the constant temperature, and it pointed at the place of the fire on the receiving board, and Fixed portion of the electric power supply cable coated with the fire retardant coating did not work as the fireproof. The heating tube was covered with the fireproof about 30 minutes.

• Progress in Medical Physics
• /
• v.14 no.2
• /
• pp.131-140
• /
• 2003

As the importance of accuracy in measurings of 3-D anatomical structures continues to be stressed, an objective and quantitative of assessing image quality and accuracy of 3-D volume-rendered images is required. The purpose of this study was to evaluate the quantitative accuracy of 3-D rendered images obtained with MDCT, scanned at various scanning parameters (scan modes, slice thicknesses and reconstruction slice thickness). Twelve clinically significant points that play an important role for the craniofacial bone in plastic surgery and dentistry were marked on the surface of a dry human skull. The direct distances between the reference points were defined as gold standards to assess the measuring errors of 3-D images. Then, we scanned the specimen with acquisition parameters of 300 mA, In kVp, and 1.0 sec scan time in axial and helical scan modes (pitch 3:1 and 6:1) at 1,25 mm, 2.50 mm, 3.75 mm and 5.00 mm slice thicknesses. We performed 3-D visualizations and distance measurements with volumetric analysis software and statistically evaluated the quantitative accuracy of distance measurements. The accuracy of distance measurements on the 3-D images acquired with 1.25, 2.50, 3,75 and 5.00 mm slice thickness were 48%, 33%, 23%, 14%, respectively, and those of the reconstructed 1.25 mm were 53%, 41%, 43%, 36% respectively. Meanwhile, there were insignificant statistical differences (P-value<0.05) in the accuracy of the distance measurements of 3-D images reconstructed with 1.25 mm thickness. In conclusion, slice thickness, rather than scan mode, influenced the quantitative accuracy of distance measurements in 3-D rendered images with MDCT. The quantitative analysis of distance measurements may be a useful tool for evaluating the accuracy of 3-D rendered images used in diagnosis, surgical planning, and radiotherapeutic treatment.

• Journal of the Society of Disaster Information
• /
• v.11 no.4
• /
• pp.556-569
• /
• 2015

With about 75% of the population of Korea criticizing the government's disaster policy and a failure to respond to large-scale emergency like the Sewol ferry sinking means that there is a deep distrust in the government. In order to prevent dreadful disasters such as the Sewol ferry sinking, it is important to secure a prime time with respect to disaster safety. Improving crisis management skills and managerial role of police officers who are in close proximity to the people is necessary for the success of disaster management. With disaster management as one of the most essential missions of the police, as a part of a national crisis management, a step by step strengthening of the disaster safety management system of the police is necessary, as below. First, at the prevention phase, law enforcement officers were not injected into for profit large-scale assemblies or events, but in the future the involvement, injection should be based on the level of potential risk, rather than profitability. In the past and now, the priortiy was the priority was on traffic flow, traffic communication, however, the paradigm of traffic policy should be changed to a safety-centered policy. To prevent large-scale accidents, police investigators should root out improper routines and illegal construction subcontracting. The police (intelligence) should strengthen efforts to collect intelligence under the subject of "safety". Second, with respect to the preparatory phase, on a survey of police officers, the result showed that 72% of police officers responded that safety management was not related to the job descriptions of the police. This, along with other results, shows that the awareness of disaster safety must be adopted by, or rather changed in the police urgently. The training in disaster safety education should be strengthened. A network of experts (private, administrative, and police) in safety management should be established to take advantage of private resources with regard to crisis situtions. Third, with respect to the response phase, for rapid first responses to occur, a unified communication network should be established, and a real-time video information network should be adopted by the police and installed in the police situation room. Fourth, during the recovery phase, recovery teams should be injected, added and operated to minimize secondary damage.

• Proceedings of the KSCN Conference
• /
• 2003.11a
• /
• pp.1058-1059
• /
• 2003

학동기(만 6-12세)에 좋은 영양 공급은 일생의 성장 발육의 기초를 조성하여 지적, 사회적, 정서적 능력을 향상시킬 수 있다. 이에 초등학생의 영양문제와 식습관을 해결하는 방안의 하나로 최근 대두되고 있는 아침결식률을 낮추기 위한 ‘아침 안 거르기’ 사업을 학교와 연계 개발하여 프로그램을 진행하고 그 효과를 평가하였다. 이 연구는 서울시 강북구 관내에 위치한 4개 초등학교 5학년 학생 1026명(실험군 451명, 대조군 675명)을 대상으로 4∼9월까지 6개월간 5단계로 실시되었다. 프로그램의 효과평가를 위해 사전(실험군-학생 428명, 부모 416명, 대조군-학생 656명, 부모 589명), 사후(실험군-학생 427명, 부모 368명, 대조군-학생 608명, 부모 558명) 설문조사를 2회 실시하여 행동과 인식률 변화를 측정하였다. 프로그램은 매월 1회 담임교사가 진행하였고, 교육자료 및 홍보물은 아침먹기 캐릭터 가방걸이와 학부모의 참여를 높이고자 가정통신문과 교육내용을 함께 삽입하여 제작한 알림장, 아침먹기와 일찍자기를 실천할 실천스티커를 배포하였고 프로그램 종료 후 아침 먹기 실천달력을 제공하였다. 또 아동들 자신의 식생활을 바르게 꾸려 나갈 수 있도록 가공식품의 ‘영양표시’에 관한 교육을 함께 교육하였고, 설문조사를 통해 영양표시제에 관한 인식변화와 행동변화율을 측정하였다. 학생들의 아침식사 실천율은 매일 먹는 그룹이 실험군은 62.9%에서 69.6%로 7% 상승하였고, 전혀 먹지 않는 그룹은 11.2%에서 6.4%로 4.8% 감소하였다(p<0.001) 대조군의 경우 매일 먹는 그룹은 70.4%에서 70.2%로, 전혀 먹지 않는 그룹은 6.9%에서 6.5%로 나타났다(p<0.001). 아침식사가 건강에 미치는 영향에 대한 인식률 변화는 큰 영향이 있다고 답한 그룹이 실험군은 60.1%에서 64.8% (p<0.001)로, 대조군은 64.8%에서 57.2% (p<0.001)로 각각 변화하였다. 일찍 자기가 건강에 미치는 영향에 대한 인식률은 큰 영향이 있다고 답한 그룹이 실험군은 52.5%에서 70.7%(p<0.001), 대조군은 55.3%에서 60.2%로(p<0.001), 일찍 자기 실천에 대한 의지 변화는 11시 이전에 잘 계획이라는 그룹이 실험군은 31.9%에서 43.9%(p<0.001), 대조군은 35.5%에서 36.8%로 나타났다(p<0.001). 영양 표시에 관한 문항에서는 식품구매시 영양표시를 보고 구매한 경험이 없다는 군이 실험군에서는 58.2%에서 40.4%로 감소하였고(p<0.001), 대조군은 64%에서 53.6% (P<0.001)로 감소하였다. 영양소에 관한 지식 평가에서 짜지 않은 간식을 선택할 때 유의할 성분을 나트륨이라고 답한 그룹은 실험군은 31.7%에서 56.3%로, 대조군은 15.9%에서 23.0%로 나타나 그룹간 큰 차이를 보였다. 아침식사로 좋아하는 음식은 김치, 김치찌개, 밥, 피자, 고기, 빵, 된장찌개, 김, 햄, 계란후라이 순이었으며 싫어하는 아침음식은 피망, 고추, 양파, 김치, 시금치, 마늘, 콩, 파, 피자, 나물순으로 나타났다. 아침식사로 혼자서도 준비할 수 있는 음식은 밥, 라면, 계란후라이, 김치, 반찬, 볶음밥, 계란, 국, 햄, 씨리얼 순으로 나타났다. 부모의 인식률 변화는 가정내에 컴퓨터 설치장소로 적합하다고 생각되는 장소로 실험군의 경우 학생 방은 28.0%에서 21.6%로 6.4%감소하였고, 마루나 거실은 61.3%에서 66.0%로 5%증가하였다(p<0.001). 반면 대조군의 경우 학생 방은 28.8%에서 24.9%로 3.9% 감소, 마루나 거실은 63.4%에서 65.9%로 2.5%증가하여 실험군과 큰 차이를 보였다(p<0.001) 자녀의 늦은 취침시간과 아침식사에 관한 인식률 변화는 아침식사에 영향이 있다는 군은 실험군의 경우 78.1%에서 82.7%로 4.2% 증가하였고(p<0.05), 대조군의 경우 82.2%에서 80.5%로 감소하여 나타났다.(P<0.001) 연구결과 실험군의 경우 일주일 동안 아침을 전혀 먹지 않는 학생이 감소하고 매일 아침을 먹는 학생이 유의적으로 증가하여 아동의 아침식사 행동변화와 인식률 변화에 도움이 된 것으로 나타났다.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.6
• /
• pp.421-428
• /
• 2014

For the analysis of water supply network, demand-driven and pressure-driven analysis methods have been proposed. Of the two methods, demand-driven analysis (DDA) can only be used in a normal operation condition to evaluate hydraulic status of a pipe network. Under abnormal conditions, i.e., unexpected pipe destruction, or abnormal low pressure conditions, pressure-driven analysis (PDA) method should be used to estimate the suppliable flowrate at each node in a network. In order to carry out the pressure-driven analysis, head-outflow relationship (HOR), which estimates flowrate at a certain pressure at each node, should be first determined. Most previous studies empirically suggested that each node possesses its own characteristic head-outflow relationship, which, therefore, requires verification by using actual field data for proper application in PDA modeling. In this study, a model pipe network was constructed, and various operation scenarios of normal and abnormal conditions, which cannot be realized in real pipe networks, were established. Using the model network, data on pressure and flowrate at each node were obtained at each operation condition. Using the data obtained, previously proposed HOR equations were evaluated. In addition, head-outflow relationship at each node was analyzed especially under multiple pipe destruction events. By analyzing the experimental data obtained from the model network, it was found that flowrate reduction corresponding to a certain pressure drop (by pipe destruction at one or multiple points on the network) followed intrinsic head-outflow relationship of each node. By comparing the experimentally obtained head-outflow relationship with various HOR equations proposed by previous studies, the one proposed by Wagner et al. showed the best agreement with the exponential parameter, m of 3.0.

• Journal of the Korean Society of Urban Environment
• /
• v.18 no.4
• /
• pp.485-494
• /
• 2018

This study aims to identify the characteristics of oxidation and chemical composition of PM in winter season, 2017 at Incheon area. The mean concentration of air pollutants were $46{\pm}22{\mu}g/m^3-PM_{10}$, $29{\pm}18{\mu}g/m^3/-PM_{2.5}$, $5{\pm}3ppb-SO_2$, $0.56{\pm}0.24ppm-CO$, $21{\pm}13ppb-O_3$ and $28{\pm}17ppb-NO_2$, respectively. The dominant ion of the $PM_{1.0}$ chemical component were organic with $3.2{\mu}g/m^3$ and nitrate with $1.9{\mu}g/m^3$. The day and night variation of the $PM_{1.0}$ chemical components was higher in nighttime than those of daytime. The averaged nitrate oxidation rate (SOR) was 0.06 and sulfate oxidation rate was 0.11 during the field campaign. In the high mass loading period, nitrate oxidation rate (NOR) was up to 0.6 and also the nitrate in $PM_{1.0}$ was increased. The averaged ratio of $NO_x/SO_2$ was 8.7 and nitrate/sulfate was 3.1, respectively. In this results, the nitrate component in $PM_{1.0}$ was influenced by NOx from the stationary source as power plant and the mobile source around the measurement site.

• The Journal of Korean Society for Radiation Therapy
• /
• v.33
• /
• pp.25-33
• /
• 2021

Purpose : The purpose of this study is to evaluate the accuracy and usefulness of the Trigger mode for the Respiratory Gated Radiation Therapy (RGRT) Materials and methods : A QUASAR respiratory phantom that inserted a 3 mm fiducial marker (a gold marker) was used to estimate the accuracy of the Trigger mode. And the 20 bpm was used as reference respiration rate in this study. The marker that placed at the center of the phantom was contoured, and the lower threshold of a gating window was fixed at 2.0 mm using an OBI with Truebeam STx^TM. The upper threshold was measured every 0.5 mm from 1.0 mm to 3.0 mm. The respiration rates were changed every 10 bpm from 10 bpm to 60 bpm. We repeatedly measured five times to check the error rate of the trigger mode in the same condition. Result : The differences of a distance from a peak phase to upper threshold, 1.0 to 3.0 mm at a 20 bpm as a reference for 3 days in a row were 0.68±0.05 mm, 0.91±0.03 mm, 1.23±0.03 mm, 1.42±0.04 mm, and 1.66±0.06 mm, respectively. Measurement result of changes in respiratory rate compared to baseline respiratory rate in maximum absolute difference. The coefficient of determination (R2) to estimate the correlation between the respiration velocity and variation of absolute difference was on average 0.838, 0.887, 0.770, 0.850, and 0.906. The p-values of all the variables were below 0.05. Conclusion : Using Trigger mode during respiratory gated radiation therapy (RGRT), accuracy and usefulness of trigger mode at reference breathing rate were confirmed. However, inaccuracies depending on the rate of breathing it could be uncertain in case of respiration rate is faster than 20 bpm as a standard respiration rate compared to slower than 20 bpm. Consequently, when conducting a RGRT using the trigger mode, real time monitoring is required with well educated respiration.

• Journal of the Korean earth science society
• /
• v.43 no.1
• /
• pp.151-164
• /
• 2022

According to the records of historical and instrumental earthquakes, the southeastern part of the Korean Peninsula is considered the highest seismic activity area. Owing to recent reports of numerous Quaternary faults along the Yangsan and Ulsan fault zones, paleoseismological studies are being actively conducted in these areas. The study area is located in the central part of the Ulsan fault zone, where the largest number of active faults have been reported. Based on lineament and geomorphic analysis using LiDAR images and aerial photographs, fault-related landforms showing topographic relief were observed and a trench survey was conducted. The trench length 20 m, width 5 m, depth 5 m is located approximately 300 m away to the northeast from the previously reported Malbang fault. From the trench section, we interpreted the geometric and kinematic characteristics of the fault based on the deformed features of the Quaternary sedimentary layers. The attitude of the reverse fault, N26°W/33°NE, is similar to those of the reported faults distributed along the Ulsan fault zone. Although a single apparent displacement of approximately 40 cm has been observed, the true displacement could not be calculated due to the absence of the slickenline on the fault plane. Based on the geochronological results of the cryogenic structure proposed in a previous study, the most recent faulting event has been estimated as being earlier than the late Wurm glaciation. We interpreted the thrust fault system of the study area as an imbrication structure based on the previous studies and the fault geometry obtained in this additional trench. Although several previous investigations including many trench surveys have been conducted, they found limited success in obtaining the information on fault parameters, which could be due to complex characteristics of the reverse fault system. Additional paleoseismic studies will contribute to solving the mentioned problems and the comprehensive fault evolution.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.30 no.1
• /
• pp.13-19
• /
• 2024

An analysis of the coastal water temperature in the Tongyeong waters, the eastern sea of the South Sea of Korea, revealed that the water temperature rose sharply before the typhoon made landfall. The water temperature rise occurred throughout the entire water column. An analysis of the sea surface temperature data observed by NOAA(National Oceanic and Atmospheric Administration) satellites, indicated that sea water with a temperature of 30℃ existed in the eastern waters of the eastern South Sea of Korea before the typhoon landed. The southeastern sea of Korea is an area where ocean currents prevail from west to east owing to the Tsushima Warm Current. However, an analysis of the satellite data showed that seawater at 30℃ moved from east to west, indicating that it was affected by the Ekman transport caused by the typhoon before landing. In addition, because the eastern waters of the South Sea are not as deep as those of the East Sea, the water temperature of the entire water layer may remain constant owing to vertical mixing caused by the wind. Because the rise in water temperature in each water layer occurred on the same day, the rise in the bottom water temperature can be considered as owing to vertical mixing. Indeed, the southeastern sea of Korea is a sea area where the water temperature can rise rapidly depending on the direction of approach of the typhoon and the location of high temperature formation.

• Korean Journal of Environmental Biology
• /
• v.35 no.2
• /
• pp.105-115
• /
• 2017

The present study is to understand the Bongseonsa stream in the National Arboretum fish fauna variation through comparison with historical data and to evaluate the stream health situated. We performed investigations over three times from April to September 2015. In the survey, 2,960 individuals which belonging to 22 species, 8 families were collected. Dominant species by number was Zacco platypus and subdominant species was Zacco koreanus. Seven Korean endemic species (Squalidus gracilis majimae, Microphysogobio yaluensis, Zacco koreanus, Koreocobitis rotundicausata, etc) were observed and showed a ratio of 36.4%. The community analysis revealed that the structure of fish community in the study sampling sites was instability in having dominance 0.79 (${\pm}0.15$), diverse 1.21 (${\pm}0.60$), evenness 0.58 (${\pm}0.15$) and species richness 1.49 (${\pm}0.83$). The values in the Qualitative Habitat Evaluation Index (QHEI) was averagely 122.9 (${\pm}44.8$) in the Bongseonsa stream and this was showed to have favorable habitat surroundings. As a result of tolerance guild analysis, the total number of sensitive species and intermediate species were higher than tolerant species. Analysis was divided into A and B two groups of fiducial 12.25% in Cluster analysis degree of similarity between study sampling sites. Fish Assessment Index (FAI) was rated A and B grade in Bongseonsa stream that stream health showed favorable. However Wangsuk stream as a urban stream rated C grade and analysed the lowest grade in the whole study sampling sites. There was high correlation beteween FAI and various indexes, dominance, diverse, evenness and sensitive species and intermediate species.