• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.979-995
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• 2023

As wildfires are difficult to predict, real-time monitoring is crucial for a timely response. Geostationary satellite images are very useful for active fire detection because they can monitor a vast area with high temporal resolution (e.g., 2 min). Existing satellite-based active fire detection algorithms detect thermal outliers using threshold values based on the statistical analysis of brightness temperature. However, the difficulty in establishing suitable thresholds for such threshold-based methods hinders their ability to detect fires with low intensity and achieve generalized performance. In light of these challenges, machine learning has emerged as a potential-solution. Until now, relatively simple techniques such as random forest, Vanilla convolutional neural network (CNN), and U-net have been applied for active fire detection. Therefore, this study proposed an active fire detection algorithm using state-of-the-art (SOTA) deep learning techniques using data from the Advanced Himawari Imager and evaluated it over East Asia and Australia. The SOTA model was developed by applying EfficientNet and lion optimizer, and the results were compared with the model using the Vanilla CNN structure. EfficientNet outperformed CNN with F1-scores of 0.88 and 0.83 in East Asia and Australia, respectively. The performance was better after using weighted loss, equal sampling, and image augmentation techniques to fix data imbalance issues compared to before the techniques were used, resulting in F1-scores of 0.92 in East Asia and 0.84 in Australia. It is anticipated that timely responses facilitated by the SOTA deep learning-based approach for active fire detection will effectively mitigate the damage caused by wildfires.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.182-193
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• 2022

Purpose: By measuring and evaluating the risk of biodiesel through non-volatile residue (NVR) and flash point and explosion limit measurement at a specific temperature according to ASTM test standards, the risk of chemical fire causative substances is identified and a universal evaluation method By derivation and securing the risk-related data of the material, it can be used for the identification and analysis of the cause of the fire, and it can be applied to the risk assessment of other chemical substances Method: In order to measure the risk of biodiesel, it was measured using the non-volatile residue(NVR) measurement method, which measures how much flammable liquid is generated at a specific temperature. Heating was tested by applying KS M 5000: 2009 Test Method 4111. In addition, the flash point was measured using the method specified in ASTM E659-782005, and the energy supply method was measured using the constant temperature method. In addition, the explosion limit measurement was conducted in accordance with ASTM E 681-04 「Standard test method for concentration limits of flammability of chemicals(Vapors and gases)」 test standard. Result: As a result of checking the amount of combustible liquid by the non-volatile residue (NVR)measurement method, the non-volatile residue(NVR) of general diesel when left at 105±2℃ for 3 hours was about 30% (70% of volatile matter) and about 4% of biodiesel. In addition, similar results were obtained for the non-volatile residue(NVR)heating temperature of 150±2℃, 3 hours and 200±2℃ for 1 hour, and white smoke was generated at 200℃ or higher. In addition, similar values were obtained as a result of experimentally checking the explosion (combustion) limits of general diesel, general diesel containing 20% biodiesel, and 100% biodiesel. Therefore, it was confirmed that the flammability risk did not significantly affect the explosion risk. Conclusion: The results of this study suggested the risk judgment criteria for mixtures through experimental research on flammable mixtures for the purpose of securing the effectiveness, reliability, and reproducibility of the details of the criteria for determining dangerous substances in the existing Dangerous Materials Safety Management Act. It will be possible to provide reference data for the judgment criteria for flammable liquids that are regulated in the field. In addition, if the know-how for each test method is accumulated through this study, it is expected that it will be used as basic data in the research on risk assessment of dangerous substances and as a basis for research on the determination of dangerous substances.

• The Journal of the Petrological Society of Korea
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• v.28 no.1
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• pp.39-52
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• 2019

Volcanic activity, which can read to various danger and hazards to human life, has been part of the Earth's history for a long time. There are approximately 1,520 volcanoes during the Holocene period (about 10,000 years ago) that have been active on Earth. Recently, there are about 210 volcanoes have been recorded since 2010. Meanwhile, there are 83 known active volcanoes in 2018 based on the USGS data. Approximately 80-90 volcanoes are active on Earth for over a year. More than 90% of these volcanoes are located on the circum-Pacific volcanic belt, commonly known as 'Ring of Fire'. This high number of active volcanoes within this area coincides with the distribution maps of active volcanoes on the earth: about 80% on subduction zone of the convergent plate boundaries; 15% on divergent plate boundaries and 5% on intra-plate zone. Five volcanoes are most active during the survey period of 51 weeks: 50 times in Aira (Japan), 49 times in Sabankaya (Peru), 49 times in Sheveluch (Russia), 44 times in Ebeko (Russia) and 40 times in Kirishimayama (Japan). Based on the available data about volcanic activity, there is no significant change in volcanic activity and similar levels of volcanic activity is observed every year.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.587-596
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• 2021

Naval battleships have systems to perform special purposes, such as the Command and Fire Control System (CFCS). Some of the this equipment should be equipped with an Uninterruptible Power System (UPS ) to ensure operational continuity and the backup of important data, even during unexpected power outages caused by problems with the ship's power generator. Heavy combat losses can occur if the equipment cannot satisfy the function. Therefore, it is important to design a stable UPS. The battery and Battery Management System (BMS) are two of the most important factors for designing a stable UPS. A power outage will be encountered if the battery and BMS are not stable. The customer will be exposed to abnormal situations, loss of important tactical data, and inability to operate some of the CFCS. As a result, an enhanced safety system should be designed. Thus, this study implemented and verified the improved system in terms of three methods, such as comparative analysis of the batteries, improvement about leakage current of the circuit, and tests of the aggressive environmental resistance to improve the UPS for CFCS.

• Journal of the Korea Institute of Building Construction
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• v.17 no.4
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• pp.377-384
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• 2017

It is generally acknowledged that subcontractors mostly allocate their resources to project relying on their previous experiences, instead of data-based judgement. Installing residential fire protection systems, typically performed by subcontractors, is labor-intensive job and its schedule is frequently changed as the contractor master schedule is often revised. Nevertheless, it is still important for subcontractors to make much effort to improve labor productivity through a thorough planning for scheduling and resource allocation. The purpose of this study is to identify significant factors that affect labor productivity for residential fire protection system installation. For this purpose, 50 potential factors that may affect productivity were identified based on literature reviews and expert interviews. These factors were further explored using correlation analysis and ANOVA test. The results showed that the labor productivity is significant impacted by various project characteristics.

• Fire Science and Engineering
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• v.24 no.6
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• pp.7-12
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• 2010

This paper is aimed the measurement and estimation the thermal interrelation based on leakage current. The leakage models are analyzed by parameters in open and closed (Panel) states and with wood dust and rainwater, charcoal powder in leakage current occurred point. The thermal characteristic of open state that leakage current is inputted in 90 mA is higher in charcoal powder ($105^{\circ}C$) than in wood dust and rainwater ($88.8^{\circ}C$). Charcoal powder that is inputted in 110 mA shows high thermal characteristic ($238.6^{\circ}C$) and the thermal ($238.6^{\circ}C$) is caused by material strain of electrical wire insulation and Panel. The closed state in 90 mA is higher in charcoal powder ($250.6^{\circ}C$) than in wood dust and rainwater ($90.8^{\circ}C$). The open and closed state appear thermal characteristics of two times in charcoal powder than in wood dust and rainwater. The thermal data that are open and close states are used electrical fire investigation and thermal characteristic for Leakage current.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.4
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• pp.628-645
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• 2010

To perform the engagement level simulation between the underwater vehicle model and the surface model those are constituted with various systems/ sub-systems, we implemented four different federates as a federation according to the IEEE 1516 HLA (High Level Architecture) protocol that is the international standard in the distributed simulation. Those are CFCS (Command and Fire Control System) federate, motion federate, external entities (torpedos, countermeasure and surfaceship) federate, and visualization federate that interacts with OSG (Open Scene Graph)-based visualization rendering module. In this paper, we present the detailed method about the model constitution for discrete event simulation in the distributed environment. For the sake of this purpose, we introduce the DEVS (Discrete Event System Specification)-HLA-based modeling method of the CFCS federate that reflects not only the interations between models, but also commands from user and tactics manager that is separated from the model. The CFCS federate makes decisions in various missions such as the normal diving, the barrier misision, the target motion analysis, the torpedo launch, and the torpedo evasion. In the perspective of DEVS modeling, the CFCS federate is the coupled model that has the tactical data process model, command model and fire control model as an atomic model. The message passing and time synchronization with other three federates are settled by the $m\ddot{a}k$ RTI (Runtime Infrastructure) that supports IEEE 1516. In this paper, we provides the detailed modeling method of the complicated model that has hierarchical relationship such as the CFCS system in the submarine and that satisfies both of DEVS modeling method for the discrete event simulation and HLA modeling method for the distributed simulation.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.15-25
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• 2023

The effects of forest fires on the activity of microbial communities in topsoil and subsoil were investigated. Samples were collected from Korean forest soils comprising mainly igneous and sedimentary rocks. Analysis of beta-glucosidase, found higher microbial activity in sedimentary rocks than in igneous rocks. Enzyme activity was not observed immediately after fire, but was restored over time. The enzyme activity of subsoil was inhibited by 33~46% compared with that in the topsoil, regardless of soil damage. The effect of fire on the availability of microbial substrate was investigated using EcoPlate. The percentages of average well color development values of damaged and normal topsoil were 52.7~56.8% and 62.3~83.6%, respectively. Forest fires appear to affect the diversity and substrate availability of the subsoil microbial community by accelerating the decomposition of soil organic matter. The Shanon index, representing microbial biodiversity, was high in the topsoil of all samples; it was higher for soil microorganisms in sedimentary rocks than in igneous rocks, and higher in topsoil than in subsoil.

• Environmental Analysis Health and Toxicology
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• v.22 no.1 s.56
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• pp.91-101
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• 2007

The new chemicals are developed and circulated without the verified toxicity data. So, the accidents and occupational diseases, such as explosion, fire, suffocation about deadly poisons etc. are frequently to workers. Classifications of chemicals suited with guideline and an offer of correct chemical information data are the molt important thing for the establishment of suitable chemical management system. The GHS (Globally Harmonized System of classification and labeling of chemicals) is based with the chemical classifications and unification plan. The warning symbol and phrases are established for improvements of chemical information data system. According to these unified and improved systematic form of data, and the chemical information data, the workplaces will be presented many chemical safety and risk data correctly. In this paper, we will present constructions and accomplishment contents-based chemical management of workplace through development of chemical information data and the nice using for new chemical investigation and risk assessment of chemicals in workplaces.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.654-661
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• 2012

This study aims to identify the difference between the actual characteristics of urban station influence areas and the recognition of the importance of such characteristics in planning, by analyzing the importance of transit-oriented development (TOD) planning factors that influence the use of public transportation. In terms of the methodology for the assessment, this study gives in-depth discussions over the validity of assessment methods that utilize quantitative data and those that rely on qualitative surveys of experts. Based on such discussions, the study analyzes the importance of the actual characteristics of station influence areas (quantitative) and the characteristics in planning identified by experts (qualitative), thereby suggesting implications for the orientations for future development of station influence areas.