• Title/Summary/Keyword: Fire Simulation

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A Numerical Analysis on Performance of Parallel Type Ejector for High Altitude Simulation (고공 환경 모사를 위한 병렬형 이젝터 구성에 따른 특성 연구)

  • Shin, Donghae;Yu, Isang;Shin, Minku;Oh, Jeonghwa;Ko, Youngsung;Kim, Sunjin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.23 no.1
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    • pp.52-60
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    • 2019
  • In this study, the performance and structure of a parallel ejector comprised of multiple single ejectors were confirmed through numerical analysis. The same design variables (mass suction ratio, compression ratio, and expansion ratio) relevant to the performance of a single ejector were considered in the design of the parallel ejector. Analytical results showed that there was no significant difference in the performance of either system related to the operating mass suction ratio; however, the systemsize was significantly reduced. In addition, it was confirmed that when ejectors of the same performance capacity are arranged in parallel, the combined mass suction ratio is lower than that of the single ejector, allowing a lower pressure to be realized. The results of the analysis indicated that the parallel ejector's performance is not significantly different from that of any single ejector, but confirmed that the parallel ejector can offer a configurationdependent advantage in size and operation.

A Study on Pk(Probability of Kill) Calculation Method of the Direct Fire Weapon System using ANN (인공신경망을 적용한 직사화기 무기체계의 살상확률(Pk) 산출방법론 연구)

  • Jang, Young Cheon;Han, Hyun Jin;Lee, Ki Teak;Song, Mi Jin;Lee, Hwi Yeong;Kim, Jong Heon
    • Journal of the Korea Society for Simulation
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    • v.28 no.1
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    • pp.99-107
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    • 2019
  • Until now it has had the limitation of the target in the US JMEM to calculate the Pk with the existing method by our study. In this study, we focused on deriving a method to calculate the Pk of the actual targets except JMEM targets using ANN. We study the initial predictive model of ANN(Artificial Neural Network) from the targets data of the specification and the vulnerable area in the US JMEM(Joint Munitions Effectiveness Manuals), and calculate the actual targets vulnerable area by using this method. Finally, we propose a method to calculate the Pk by applying those data to the existing method of us.

Experimental Study for Seismic Behavior Analysis of a Fire Protection Riser Pipe System with Groove Joints (그루브 조인트가 설치된 수계소화설비 입상배관계통의 지진거동분석을 위한 실험적 연구)

  • Kim, Sung-Wan;Yun, Da-Woon;Kim, Jae-Bong;Jeon, Bub-Gyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.2
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    • pp.35-42
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    • 2021
  • In this study, a steel frame that realized the second floor of a structure was fabricated in referring to NFPA 13. In addition, a riser pipe system with groove joints was installed, and a seismic simulation test was performed using static cyclic loading. Cyclic loading tests on the maximum allowable side sway of seismic design standards for buildings in Korea were conducted using actuators to analyze the seismic behavior of the riser pipe system and major piping elements due to the deformation of the steel frame structure or the displacement-dominant behavior caused by the relative displacement between the structural members in the event of a seismic load. Moreover, the deformation angle of the riser pipe system was measured using an image measurement system because it is difficult to measure using the conventional sensors.

Simulation and Analysis of Wildfire for Disaster Planning and Management

  • Yang, Fan;Zhang, Jiansong
    • International conference on construction engineering and project management
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    • 2022.06a
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    • pp.443-449
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    • 2022
  • With climate change and the global population growth, the frequency and scope of wildfires are constantly increasing, which threatened people's lives and property. For example, according to California Department of Forestry and Fire Protection, in 2020, a total of 9,917 incidents related to wildfires were reported in California, with an estimated burned area of 4,257,863 acres, resulting in 33 fatalities and 10,488 structures damaged or destroyed. At the same time, the ongoing development of technology provides new tools to simulate and analyze the spread of wildfires. How to use new technology to reduce the losses caused by wildfire is an important research topic. A potentially feasible strategy is to simulate and analyze the spread of wildfires through computing technology to explore the impact of different factors (such as weather, terrain, etc.) on the spread of wildfires, figure out how to take preemptive/responsive measures to minimize potential losses caused by wildfires, and as a result achieve better management support of wildfires. In preparation for pursuing these goals, the authors used a powerful computing framework, Spark, developed by the Commonwealth Scientific and Industrial Research Organization (CSIRO), to study the effects of different weather factors (wind speed, wind direction, air temperature, and relative humidity) on the spread of wildfires. The test results showed that wind is a key factor in determining the spread of wildfires. A stable weather condition (stable wind and air conditions) is beneficial to limit the spread of wildfires. Joint consideration of weather factors and environmental obstacles can help limit the threat of wildfires.

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A Prototype for Real-time Indoor Evacuation Simulation System using Indoor IR Sensor Information (적외선 센서정보기반 실시간 실내 대피시뮬레이션 시스템 프로토타입)

  • Nam, Hyun-Woo;Kwak, Su-Yeong;Jun, Chul-Min
    • Spatial Information Research
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    • v.20 no.2
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    • pp.155-164
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    • 2012
  • Indoor fire simulators have been used to analyse building safety in the events of emergency evacuation. These applications are primarily focused on simulating evacuation behaviors for the purpose of checking building structural problems in normal time rather than in real time situations. Therefore, they have limitations in handling real-time evacuation events with the following reasons. First, the existing models mostly experiment the artificial situations using randomly generated evacuees while real world requires actual data. Second, they take too long time in operation to generate real time data. Third, they do not produce optimal results to be used in rescueing or evacuation guidance. In order to solve these limitations, we suggest a method to build an evacuation simulation system that can be used in real-world emergency situations. The system performs numerous simulations in advance according to varying distributions of occupants. Then the resulting data are stored in DBMS. The actual person data captured in infrared sensor network are compared with the simulation data in DBMS and the querried data most closely is provided to the user. The developed system is tested using a campus building and the suggested processes are illustrated.

A Study on Pk(Probability of Kill) Calculation Method of the Direct Fire Weapon System using Simulation (시뮬레이션 기반 직사화기 무기체계의 살상확률 산정 방법에 관한 연구)

  • Choi, Yun Ho;Lee, Ki Teak;Pyun, Jai Jeong;Jang, Young Cheon
    • Journal of the Korea Society for Simulation
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    • v.26 no.3
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    • pp.115-123
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    • 2017
  • Dispite the fact that our military has outwardly made notable accomplishments such as the development of weapon systems like tanks, self-propelled artillery, and missiles, there has been a lack of attention to producing weapon effectiveness data that suggests a standard as to what effects the developed weapons will demonstrate on the battlefield. For such reasons, most of the weapon effectiveness data utilizes JMEM data introduced by the United States and as for the rest of the data that cannot be acquired, respective branches create and utilize their own data through research. This research aims to develop a reliable methodology that can meet the requirements of the requesting branches in a short span of time and at a low cost by studying the existing weapon effectiveness data production methodologies such as that of JMEM. As a result I have developed a method that calculates the vulnerable area and the probability of kill of the weapon system that one wants to calculate by applying statistical technique and simulation technique based on weapon effectiveness data of similar weapon systems in JMEM and live test data.

Video smoke detection with block DNCNN and visual change image

  • Liu, Tong;Cheng, Jianghua;Yuan, Zhimin;Hua, Honghu;Zhao, Kangcheng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.9
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    • pp.3712-3729
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    • 2020
  • Smoke detection is helpful for early fire detection. With its large coverage area and low cost, vision-based smoke detection technology is the main research direction of outdoor smoke detection. We propose a two-stage smoke detection method combined with block Deep Normalization and Convolutional Neural Network (DNCNN) and visual change image. In the first stage, each suspected smoke region is detected from each frame of the images by using block DNCNN. According to the physical characteristics of smoke diffusion, a concept of visual change image is put forward in this paper, which is constructed by the video motion change state of the suspected smoke regions, and can describe the physical diffusion characteristics of smoke in the time and space domains. In the second stage, the Support Vector Machine (SVM) classifier is used to classify the Histogram of Oriented Gradients (HOG) features of visual change images of the suspected smoke regions, in this way to reduce the false alarm caused by the smoke-like objects such as cloud and fog. Simulation experiments are carried out on two public datasets of smoke. Results show that the accuracy and recall rate of smoke detection are high, and the false alarm rate is much lower than that of other comparison methods.

Risk Assessment of High Pressure HCNG Refueling Station Explosion by Numerical Simulation (시내버스용 HCNG 고압가스 충전소의 폭발 위험성 해석)

  • Kang, Seung-Kyu;Kim, Young-Gu;Choi, Seul-Ki;Kwon, Jeong-Rak
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.113-113
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    • 2014
  • This study has been conducted for evaluation of qualitative/quantitative risk of HCNG filling station. In case of fire explosion occurred because of hydrogen, CNG, and HCNG leaking on same conditions, maximum overpressure was measured as 30kPa for hydrogen, 3.5kPa for HCNG, and 0.4kPa for CNG. The overpressure of HCNG was measured 7.75 times higher than that of CNG, but it was only 11.7% compared with hydrogen. When the explosion was occurred, in case of hydrogen, the measured influential distance of overpressure was 59m and radiant heat was 75m. In case of CNG, influential distance of overpressure was 89m and radiant heat was 144m would be estimated. In case of 30% HCNG that was blended with hydrogen and CNG, influential distance of overpressure was 81m and radiant heat was 130m were measured. As the explosion occurred with the same sized container that had 350bar for hydrogen and 250bar of CNG and HCNG, the damage distance that explosive overpressure and radiant heat influenced CNG was seen as the highest. HCNG that was placed between CNG and hydrogen tended to be seen as more similar with CNG.

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Acceptable Velocity Errors Tolerance For Field Artillery Weapon System (야전포병 무기체계의 속도오차 허용한계)

  • Min Kye-Ryo;Bai Do-Sun
    • Journal of the military operations research society of Korea
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    • v.2 no.1
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    • pp.163-176
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    • 1976
  • The artillery fire is characterized by great damage that can be inflicted simultaneously to an area through concentrated firing. The field artillery guns used in R.O.K. Army are generally old. Thus high values of their velocity errors cause wide dispersion of shell landings. Therefore effects of the concentrated firing is lessened. In this paper a general model which considers all error factors involved in firing in general, is established first. Then from this a basic model which includes the errors involved in concentrated firing only, such as the ballistic error, velocity error, target density function, and damage function, is extracted. Among many weapon systems now in use a specific one called gun 'A' is selected and its concentration effects are measured through computer simulation. The results show that as the velocity error of a battery increases, its target coverage capability, i. e. concentration effect, decreases. Therefore the need arises for the field artillery commander to know beforehand characteristics, i.e. velocity errors, of the guns in his unit and also to carefully examine the problem of battery arrangement with the gun characteristics in mind in order to maximize the damage effects of his artillery unit.

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A Study on the Overpressure Estimation of BLEVE (BLEVE로 인한 과압 예측에 관한 연구)

  • Kim In-Tae;Kim In-Won;Song Hee-Oeul
    • Journal of the Korean Institute of Gas
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    • v.4 no.1 s.9
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    • pp.69-76
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    • 2000
  • Explosion Quantities and flashing mass resulting from the variation of temperature are calculated by a computer program, BLEVE ESTIMATOR, to carry out the risk assessment of BLEVE. The damages caused by the BLEVE are estimated under the explosion of the simulation condition similar to the Puchun LP gas station accident, and the results are compared with the commercial program SAFER of Dupont CO. Explosion quantities and flashing mass increase exponentially with the increase of explosion temperature. These values for propane are relatively higher than those for n-butane. In conditions of higher vessel temperature, vessel pressure, and liquid ratio of containment, higher overpressures are calculated.

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