• Applied Chemistry for Engineering
• /
• v.34 no.2
• /
• pp.144-152
• /
• 2023

To evaluate the fire risk of combustible materials, Chung's equations VII, VIII, and IX were newly established. The fire risk index-IX (FRI-IX) and fire risk rating (FRR) were calculated. Ginkgo, dawn redwood, toona, lime, walnut, and polymethylmethacrylate (PMMA) were selected as test specimens. The combustion characteristics were evaluated using a cone calorimeter according to ISO 5660-1. After combustion, the fire performance index-VII (FPI-VII) of the specimens, varied between 15.15 and 182.53 s²/kW, as determined by Chung's equations, and the fire growth index-VII (FGI-VII) varied between 0.0023 and 0.0165 kW/s². The fire performance index-VIII (FPI-VIII) based on PMMA varied between 0.29 and 3.45, and the fire growth index-VIII (FGI-VIII) varied between 2.88 and 20.63. The FRI-IX, which is the fire risk rating, showed dawn redwood has a very high fire risk, with FRI-IX values of 71.14 (fire risk rating: G). Therefore, wood with a large amount of volatile organic compounds and a low bulk density showed a high value of FRI-IX by lowering FPI-VII and FPI-VIII and increasing FGI-VII and FGI-VIII.

• Land and Housing Review
• /
• v.14 no.2
• /
• pp.125-135
• /
• 2023

Drones are used in various fields, including land survey, transportation, forestry/agriculture, marine, environment, disaster prevention, water resources, cultural assets, and construction, as their industrial importance and market size have increased. In this study, image data for deep learning was collected using a mavic3 drone capturing images at a shooting altitude was 20 m with ×7 magnification. Swin Transformer and UperNet were employed as the backbone and architecture of the deep learning model. About 800 sheets of labeled data were augmented to increase the amount of data. The learning process encompassed three rounds. The Cross-Entropy loss function was used in the first and second learning; the Tversky loss function was used in the third learning. In the future, when the crack detection model is advanced through convergence with the Internet of Things (IoT) through additional research, it will be possible to detect patching or potholes. In addition, it is expected that real-time detection tasks of drones can quickly secure the detection of pavement maintenance sections.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.8 no.4
• /
• pp.285-296
• /
• 2018

Among many hacking attempts carried out in the past few years, the cyber-attacks that could have caused a national-level disaster were the attacks against nuclear facilities including nuclear power plants. The most typical one was the Stuxnet attack against Iranian nuclear facility and the cyber threat targeting one of the facilities operated by Korea Hydro and Nuclear Power Co., Ltd (Republic of Korea; ROK). Although the latter was just a threat, it made many Korean people anxious while the former showed that the operation of nuclear plant can be actually stopped by direct cyber-attacks. After these incidents, the possibility of cyber-attacks against industrial control systems has become a reality and the security for these systems has been tightened based on the idea that the operations by network-isolated systems are no longer safe from the cyber terrorism. The ROK government has established a realistic control systems defense concept and in the US, the relevant authorities have set up several security frameworks to prepare for the threats. This paper presented various cyber security attack cases and their scenarios against control systems, along with the analysis of countermeasures for them. Though this task, we attempt to identify the items that need to be considered when designing a domestic security framework to improve security and secure stability.

• The Journal of Bigdata
• /
• v.6 no.2
• /
• pp.1-15
• /
• 2021

The unprecedented pandemic of infectious diseases called COVID-19 has dampened human and material movement, and changes in the global economic structure have caused various economic and industrial problems such as worsening employment along with the domestic and international economic recession. In this crisis situation, the government announced the "New Deal" as a new card to enhance economic vitality following the "emergency disaster support fund." This means that the first business of the Digital New Deal, the beginning and core of the New Deal, begins digital transformation from collecting data, which is the "rice" of digital transformation to the data dam. Until now, not only the government but also local governments have established and operated platforms for collecting and sharing public data by establishing various data portals. It is evaluated that it lacks utilization for commercialization as not only the government but also local governments focus only on building the platform without considering the business model when building the initial public data platforms. In particular, in the case of regions, there is a lack of public data to be used for data business, so it is necessary to utilize data from public institutions in the region. In this study, various data collection, data quality improvement, and data utilization improvement were suggested as measures to solve these problems.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.33 no.3
• /
• pp.375-383
• /
• 2023

Objectives: Coal-fired power plants feature diverse working conditions, including multi-layered employment structures and irregular work cycles due to outsourcing and non-standardized tasks. The current uniform occupational environment measurement systems have limitations in accurately assessing and evaluating these varied conditions. This study aims to propose alternative measurement and assessment strategies to supplement existing methods. Methods: Major domestic coal-fired power plants were selected as the study targets. To prepare for the study and establish strategies, work processes were identified and existing occupational environment measurement results were compared and analyzed. The study proceeded by employing three strategies: specific exposure groups (SEGs) measurement, continuous monitoring, and supplementary measurements, which were then compared and discussed. Results: Previous exposure index evaluations (5,268 cases) indicated that crystalline silica, a type of respirable particulate matter, had detection limits below the threshold (non-detectable) in 82.6% (4,349 cases) of instances. Exposures below 10% of the exposure limit were observed at a very low concentration of 96.1%. Similar exposure group measurements yielded results where detection limits were below the threshold in 38.2% of cases, and exposures below 10% of the limit were observed in 70.6%. Continuous monitoring indicated detection limits below the threshold in 12.6% of cases, and exposures below 10% of the limit were observed in 75.6%. Instances requiring active workplace management accounted for more than 30% of cases, with SEGs at 11.8% (four cases), showing a higher proportion compared to 3.0% (four cases) in continuous monitoring. For coal dust, exposures below 10% of the limit were highest in legal measurements at 90.2% (113 cases), followed by 74.0% (91 cases) in continuous monitoring, and 47.0% (16 cases) in SEGs. Instances exceeding 30% were most prevalent in SEGs at 14.7% (five cases), followed by legal measurements at 5.0% (eight cases), and continuous monitoring at 2.4% (three cases). When examining exposure levels through arithmetic means, crystalline silica was found to be 104.7% higher in SEGs at 0.0088 mg/m³ compared to 0.0043 mg/m³ in continuous monitoring. Coal dust measurements were highest in SEGs at 0.1247 mg/m³, followed by 0.1224 mg/m³ in legal measurements, and 0.0935 mg/m³ in continuous monitoring. Conclusions: Strategies involving SEGs measurement and continuous monitoring can enhance measurement reliability in environments with irregular work processes and frequent fluctuations in working conditions, as observed in coal-fired power plants. These strategies reduce the likelihood of omitting or underestimating processes and enhance measurement accuracy. In particular, a significant reduction in detection limits below the threshold for crystalline silica was observed. Supplementary measurements can identify worker exposure characteristics, uncover potential risks in blind spots of management, and provide a complementary method for legal measurements.

• International Journal of High-Rise Buildings
• /
• v.12 no.3
• /
• pp.225-234
• /
• 2023

Even at this point in the era of digital transformation, we are still facing many problems in the safety sector that cannot prevent the occurrence or spread of human casualties. When you are in an unexpected emergency, it is often difficult to respond only with human physical ability. Human casualties continue to occur at construction sites, manufacturing plants, and multi-use facilities used by many people in everyday life. If you encounter a situation where normal judgment is impossible in the event of an emergency at a life site where there are still many safety blind spots, it is difficult to cope with the existing manual guidance method. New variable guidance technology, which combines artificial intelligence and digital twin, can make it possible to prevent casualties by processing large amounts of data needed to derive appropriate countermeasures in real time beyond identifying what safety accidents occurred in unexpected crisis situations. When a simple control method that divides and monitors several CCTVs is digitally converted and combined with artificial intelligence and 3D digital twin control technology, intelligence augmentation (IA) effect can be achieved that strengthens the safety decision-making ability required in real time. With the enforcement of the Serious Disaster Enterprise Punishment Act, the importance of distributing a smart location guidance system that urgently solves the decision-making delay that occurs in safety accidents at various industrial sites and strengthens the real-time decision-making ability of field workers and managers is highlighted. The smart location guidance system that combines artificial intelligence and digital twin consists of AIoT HW equipment, wireless communication NW equipment, and intelligent SW platform. The intelligent SW platform consists of Builder that supports digital twin modeling, Watch that meets real-time control based on synchronization between real objects and digital twin models, and Simulator that supports the development and verification of various safety management scenarios using intelligent agents. The smart location guidance system provides on-site monitoring using IoT equipment, CCTV-linked intelligent image analysis, intelligent operating procedures that support workflow modeling to immediately reflect the needs of the site, situational location guidance, and digital twin virtual fencing access control technology. This paper examines the limitations of traditional fixed passive guidance methods, analyzes global technology development trends to overcome them, identifies the digital transformation properties required to switch to intelligent variable smart location guidance methods, explains the characteristics and components of AI-based public facility smart fire safety integrated system (ISFS).

• Applied Chemistry for Engineering
• /
• v.35 no.1
• /
• pp.29-36
• /
• 2024

The fire risk and fire safety of four types of wood were comprehensively evaluated according to Chung's equation-XII. White ash, willow, fraxinus mandshurica, and sagent cherry trees were selected as test specimens. A cone calorimetery (ISO 5660-1) was used to examine the combustion characteristics of the test piece, and finally, the fire risk rating (FRR) was predicted using the fire risk index-XII (FRI-XII). The predicted fire performance index-X (FPI-X) and fire growth index-X (FGI-X) ranged from 469.03 to 1109.73 s²/kW and 0.0009 to 0.0280 kW/s², respectively. Additionally, the fire performance index-XI (FPI-XI) and fire growth index-XI (FGI-XI) ranged from 0.41 to 0.97 and 1.11 to 3.11, respectively. The fire risk index-XII (FRI-XII), representing a fire risk rating, showed that the fire risk of frasxinus mandsurica tree (FM) was very high at 7.60 (fire risk rating: D). And it was compared with Chung's equation-IX, fire risk index-IX (FRI-IX). The fire risk ratings according to FRI-IX and FRI-XII were generally high for willow and frasxinus mandsurica trees. Additionally, the results of FRI-XII and FRI-IX had a similar relationship, and the size of each fire safety rating closely matched each other.

• Geophysics and Geophysical Exploration
• /
• v.11 no.1
• /
• pp.52-59
• /
• 2008

We have developed a new deep-towed marine DC resistivity survey system. It was designed to detect the top boundary of the methane hydrate zone, which is not imaged well by seismic reflection surveys. Our system, with a transmitter and a 160-m-long tail with eight source electrodes and a receiver dipole, is towed from a research vessel near the seafloor. Numerical calculations show that our marine DC resistivity survey system can effectively image the top surface of the methane hydrate layer. A survey was carried out off Joetsu, in the Japan Sea, where outcrops of methane hydrate are observed. We successfully obtained DC resistivity data along a profile ${\sim}3.5\;km$ long, and detected relatively high apparent resistivity values. Particularly in areas with methane hydrate exposure, anomalously high apparent resistivity was observed, and we interpret these high apparent resistivities to be due to the methane hydrate zone below the seafloor. Marine DC resistivity surveys will be a new tool to image sub-seafloor structures within methane hydrate zones.

• Journal of Korean Society of societal Security
• /
• v.4 no.2
• /
• pp.73-78
• /
• 2011

In order to resolve the problem of change in global climate which is worsening as days go by and to preemptively cope with strengthened restriction on carbon emission, the government enacted 'Framework Act on Low Carbon Green Growth' in 2010 and selected green technology and green industry as new national growth engines. For this reason, the necessity to use the un-utilized waste heat across the whole industrial system has become an issue, and studies on and applications of recycling in the agricultural and fishery fields such as cultivation of tropical crops and flatfishes by utilizing the waste heat and thermal effluent generated by large industrial complexes including power plants are being actively carried out. In this study, we looked into the domestic and overseas examples of having utilized waste heat abandoned in the form of power plant thermal effluent, and carried out economic efficiency evaluation of sturgeon aquaculture utilizing thermal effluent of Yeongwol LNG Combined Cycle Power Plant in Gangwon-do. In this analysis, we analyzed the economic efficiency of a model business plan divided into three steps, starting from a small scale in order to minimize the investment risk and financial burden, which is then gradually expanded. The business operation period was assumed to be 10 years (2012~2021), and the NVP (Net Present Value) and economic efficiency (B/C) for the operation period (10 years) were estimated for different loan size by dividing the size of external loan by stage into 80% and 40% based on the basic statistics secured through a site survey. Through the result of analysis, we can see that reducing the size of the external loan is an important factor in securing greater economic efficiency as, while the B/C is 1.79 in the case the external loan is 80% of the total investment, it is presumed to be improved to 1.81 when the loan is 40%. As the findings of this study showed that the economic efficiency of sturgeon aquaculture utilizing thermal effluent of power plant can be secured, it is presumed that regional development project items with high added value can be derived though this, and, in addition, this study will greatly contribute to reinforcement of the capability of local governments to cope with climate change.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.8
• /
• pp.367-377
• /
• 2017

This study examined the effects of the salinity of seafood wastewater on the sulfur denitrification process. An examination of the denitrification efficiency showed that the optimal EBCT was 1hr at an influent T-N concentration of 20mg/L or lower and 2-3hr at an T-N concentration of 30mg/L. An examination of the denitrification efficiency according to the nitrogen load showed that the legal effluent water quality criterion was satisfied when the influent load was maintained within $0.496kg/m^3/day$. On the other hand, the reactor volume increased when this was applied to the site. Therefore, the influent load should be within $0.372kg/m^3/day$ considering the denitrification and economic efficiency. At a load of $0.248{\sim}0.628kg/m^3{\cdot}day$, the k value was $0.0890{\sim}0.5032hr^{-1}$. The batch experimental results according to the $Cl^-$ concentration showed that at an influent nitrogen concentration of 30.0mg/L, the effect of the denitrification efficiency was not large below the salinity of $7,000mgCl^-/L$, but inhibition occurred above $9,000mgCl^-/L$. Calculations of the reaction rate constant according to the $Cl^-$ concentration showed that the reaction rate constant was $0.1049{\sim}0.2324hr^{-1}$ at a raw wastewater concentration of ${\sim}5,000mgCl^-/L$. In contrast, the k value was $0.1588hr^{-1}$ at $7,000mgCl^-/L$ and $0.1049hr^{-1}$ at $9,000mgCl^-/L$.