• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.716-722
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• 2017

The present study numerically investigates the effect of obstacles located in the trajectory of fire plume flow on heat flow characteristics by using Fire Dynamics Simulation (FDS) software in an underground combined cycle power plant (CCPP). Fire size is taken as 10 MW and two different locations of fire source are selected depending on the presence of an obstacle. As the results, when the obstacle is in the trajectory of fire plume, hot plume arrives at the ceiling about 5 times slower in the upper of the fire in comparison to the results without obstacle. In addition, the average propagation time of ceiling jet increases by about 70 % with the distance from the ceiling in the upper of the fire, and it increases mainly about 4 times at the distance of 10 m. Consequently, it is noted that the analysis of heat flow characteristics in the underground CCPP considering fire scenarios is essential to develop the fire detection system for initial response on evacuation and disaster management.

• Health Policy and Management
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• v.16 no.4
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• pp.48-67
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• 2006

The aim of the study was to examine levels of satisfaction with health care in North Korea and to identify factors associated with it using a convenience sample of North Korean refugees in China. Data from the 2004 Survey of Health Seeking Behavior of North Korean Households conducted by the Center for Refugee and Disaster Response, Johns Hopkins Bloomberg School of Public Health were used. The study subjects were 273 North Korean refugees whose length of stay in China was less than 3 months. Factor analysis was used to extract factor dimensions from the 12 satisfaction items. Bivariate (t test and ANOVA) and multiple regression analyses were used in examining factors associated with satisfaction with health care use in North Korea Overall, satisfaction level was low ($2.36{\pm}0.36$, score range: 1-5). Of the three-factor dimensions, physician skills scored the highest $(2.93{\pm}0.36)$, followed by drug availability $(2.51{\pm}0.07)$ and general cleanliness $(1.66{\pm}0.55)$. In the multiple regression analysis, having a usual source of care was significantly associated with patient satisfaction. Respondents who identified primary care (section) doctors as their usual source of care tended to be less satisfied than those with the city or county hospital as their usual source of care. County residents tended to report a lower degree of satisfaction with general cleanliness than city residents. Among socioeconomic characteristics, the number of household assets positively predicted satisfaction with drug availability. North Korean residents appear to be dissatisfied with their medical care. It may reflect some inadequacies in the North's universal health care system to meet the healthcare needs of its people.

• International Journal of High-Rise Buildings
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• v.9 no.2
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• pp.127-154
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• 2020

Disproportionate collapse triggered by local structural failure may cause huge casualties and economic losses, being one of the most critical civil engineering incidents. It is generally recognized that ensuring robustness of a structure, defined as its insensitivity to local failure, is the most acceptable and effective method to arrest disproportionate collapse. To date, the concept of robustness in its definition and quantification is still an issue of controversy. This paper presents a detailed review on about 50 quantitative measures of robustness for building structures, being classified into structural attribute-based and structural performance-based measures (deterministic and probabilistic). The definition of robustness is first described and distinguished from that of collapse resistance, vulnerability and redundancy. The review shows that deterministic measures predominate in quantifying structural robustness by comparing the structural responses of an intact and damaged structure. The attribute-based measures based on structural topology and stiffness are only applicable to elastic state of simple structural forms while the probabilistic measures receive growing interest by accounting for uncertainties in abnormal events, local failure, structural system and failure-induced consequences, which can be used for decision-making tools. There is still a lack of generalized quantifications of robustness, which should be derived based on the definition and design objectives and on the response of a structure to local damage as well as the associated consequences of collapse. Critical issues and recommendations for future design and research on quantification of robustness are provided from the views of column removal scenarios, types of structures, regularity of structural layouts, collapse modes, numerical methods, multiple hazards, degrees of robustness, partial damage of components, acceptable design criteria.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.49-60
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• 2017

As well as the strength check, fatigue life check is also mainly required for designing mooring lines of the floating structures. In general, forces which induce dynamic structural response significantly affect to fatigue design of the mooring lines. So, waves are mainly considered as the governing loading for fatigue design of the mooring lines. In this study, characteristics of the fatigue damage of the mooring lines for submerged floating tunnels (SFT) under irregular waves are investigated. For this study time domain hydrodynamic analysis is used to obtain motion of the tunnel and tension and stresses of the mooring lines under the specific environmental conditions. Also, the Rainflow-counting method, the Palmgren-Miner's rule, and S-N curves for floating offshore structures presented by DNV recommendation is applied to calculate the fatigue damage due to the fluctuating stresses. Referring to the design plactice of the tendon pipes for TLP (tension-leg platform), which is very similar structural system to SFT, it is assumed that a 100 year return period wave attacks the SFT systems during 48 hours and the fatigue damages due to the environmental loading are calculated. Following the analysis sequence, the effects of the tunnel draft, spacing and initial inclination angle of the mooring lines on the fatigue damage under the specific environmental loadings are investigated.

• Fire Science and Engineering
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• v.30 no.6
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• pp.48-56
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• 2016

A crude oil leakage from a large atmospheric storage tank occurred on 4 April 2014 at 14:50 in Ulsan City, while storing the crude oil in the tank. Emergency Rescue Control Group was deployed in the scene. The company, Fire Service Headquarters and associated agencies got together in Command Post (CP) for discussing an effective corresponding strategy. Many solution plans were drafted in the debate such as power down, stopping the facilities, checking the density of inflammable gas, suppressing oil evaporation, moving the leaked crude oil to a nearby tank and a processing plant and avoiding marine pollution. All the solutions were carried out in cooperation with several agencies and partners. The oil leakage accident was successfully settled up within the process of responding, The Fire Service Headquarters and the company thought that the most important thing was the suppression of oil evaporation and the elimination of ignition source. With Fire Service Headquarters and several agencies' every effort, an explosion and a fire didn't occurred in the scene. This study suggest the improvement of the operating system in Emergency Rescue Control Group in case of petroleum leakage, explosion and fire accidents of atmospheric storage tank, different from a ordinary disaster. Assuming that petroleum leakage in atmospheric storage tank develop the explosion and fire accidents, the spreading speed of the flame and the burning time was experimented and compared with each other. Furthermore, this study concentrates on the effective field response plan prepared for the afterward explosion and fire accidents from petroleum leak in a storage tank, with the database experimented and analyzed in accordance with the angle of radiation in the foam nozzle and the pressure of pumping in a fire engine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.745-753
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• 2021

Recently, a large fire occurred in a multi-use facility used by a large number of citizens, including the vulnerable, resulting in a lot of injuries and damages. Although several pilot studies have been conducted to reduce such incidents, the development of advanced disaster response technology using the latest spatial information and IoT technology is still insufficient. In this study, a pilot test bed is built to demonstrate detailed technologies derived through the first stage of realistic fire management technology research for the development of applied technology in the field. In detail, the building conditions and candidate sites of the test bed were first investigated and analyzed to derive satisfactory conditions and candidate target buildings. A second pilot test bed was then selected, and the necessary sensor and facility infrastructure were built to demonstrate the outcomes. Finally, a scenario was produced for technology verification, and a test bed system was developed. The pilot test bed is expected to contribute to verifying intermediate outcomes of realistic fire management research projects, enhancing the quality of the developed technologies.

• Korean Security Journal
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• no.9
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• pp.99-131
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• 2005

Terrorism which became today's common phenomena over the world is one of the most serious threats the world confront. Although International society make and operate outstanding anti-terrorism system, terror would never end without solving fundamental problems. The main body of terrorism converts from nation to organization and from organization to cell, which makes it difficult for us to recognize the main body. Since the target of today's new terrorism is many and unspecified persons, terrorists will never hesitate to use mass destruction weapons such as nuclear, biological, chemical weapons, and also use cyber-technique or cyber-terrorism. So, effective counter-terrorism measures should be performed as follows. First, it must be better for international society should make long-time plan of solving fundamental problems of terrorism other than to operate directly on terror organization and its means. Second, preventive method should be made. The most effective method of eradicating terrorism is prevention. For this, it is necessary to remove environmental elements of terrorism and terrorist bases, and to stop inflow of money and mass destruction weapons to terrorists. Third, integrated anti-terror organization should be organized and operated for continuous counter-terrorism operations. Also international alliance for anti-terrorism should be maintained to share informations and measures. Fourth, concerned department in the government should prepare counter-terrorism plans in their own parts as follows and make efforts to integrate the plans. - Ministry of Government Administration and Home Affairs : conventional terror - Ministry of Health and Welfare : bio-terror - Ministry of Science and Technology : nuclear-terror Especially, they should convert their policy and operation from post-terror actions to pre-terror actions, designate terror as national disaster and organize integrated emergency response organization including civil, government, and military elements. In conclusion, pre-terror activities and remedy of fundamental causes is the best way to prevent terror. Also, strengthening of intelligence activities, international cooperations, and preventive and comprehensive counter-measures must not ignored.

• Korean Journal of Remote Sensing
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• v.36 no.5_4
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• pp.1267-1276
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• 2020

To quantitatively predict the impacts of large-scale volcanic eruptions of Mt. Baekdu on air quality and damage around the Korean Peninsula, a three-dimensional chemistry-transport modeling system (Weather Research & Forecasting - Sparse Matrix Operation Kernel Emission - Comunity Multi-scale Air Quality) was adopted. A worst-case meteorology scenario was selected to estimate the direct impact on Korea. This study applied the typical worst-case scenarios that are likely to cause significant damage to Korea among worst-case volcanic eruptions of Mt. Baekdu in the past decade (2005~2014) and assumed a massive VEI 4 volcanic eruption on May 16, 2012, to analyze the concentration of PM_2.5 caused by the volcanic eruption. The effects of air quality in each region-cities, counties, boroughs-were estimated, and vulnerable areas were derived by conducting an exposure assessment reflecting vulnerable groups. Moreover, the effects of cities, counties, and boroughs were analyzed with a high-resolution scale (9 km × 9 km) to derive vulnerable areas within the regions. As a result of analyzing the typical worst-case volcanic eruptions of Mt. Baekdu, a discrepancy was shown in areas between high PM_2.5 concentration, high population density, and where vulnerable groups are concentrated. From the result, PM_2.5 peak concentration was about 24,547 ㎍/㎥, which is estimated to be a more serious situation than the eruption of Mt. St. Helensin 1980, which is known for 540 million tons of volcanic ash. Paju, Gimpo, Goyang, Ganghwa, Sancheong, Hadong showed to have a high PM_2.5 concentration. Paju appeared to be the most vulnerable area from the exposure assessment. While areas estimated with a high concentration of air pollutants are important, it is also necessary to develop plans and measures considering densely populated areas or areas with high concentrations of susceptible population or vulnerable groups. Also, establishing measures for each vulnerable area by selecting high concentration areas within cities, counties, and boroughs rather than establishing uniform measures for all regions is needed. This study will provide the foundation for developing the standards for disaster declaration and preemptive response systems for volcanic eruptions.

• Journal of Korean Society of Disaster and Security
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• v.15 no.1
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• pp.1-12
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• 2022

An automatic optimization technique is used to estimate the optimal parameters of the hydrologic model, and different hydrologic response results can be provided depending on objective functions. In this study, the parameters of the event-based rainfall-runoff model were estimated using various objective functions, the reproducibility of the hydrograph according to the objective functions was evaluated, and appropriate objective functions were proposed. As the rainfall-runoff model, the storage function model(SFM), which is a lumped hydrologic model used for runoff simulation in the current Korean flood forecasting system, was selected. In order to evaluate the reproducibility of the hydrograph for each objective function, 9 rainfall events were selected for the Cheoncheon basin, which is the upstream basin of Yongdam Dam, and widely-used 7 objective functions were selected for parameter estimation of the SFM for each rainfall event. Then, the reproducibility of the simulated hydrograph using the optimal parameter sets based on the different objective functions was analyzed. As a result, RMSE, NSE, and RSR, which include the error square term in the objective function, showed the highest accuracy for all rainfall events except for Event 7. In addition, in the case of PBIAS and VE, which include an error term compared to the observed flow, it also showed relatively stable reproducibility of the hydrograph. However, in the case of MIA, which adjusts parameters sensitive to high flow and low flow simultaneously, the hydrograph reproducibility performance was found to be very low.

• Journal of Environmental Policy
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• v.5 no.1
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• pp.45-70
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• 2006

China has achieved great economic growth above 9% annual since it changed to more of a market economy system by its reform and open-door policy. At the same time, China has experienced severe ecological deterioration, such as air and water pollutions caused by its rapid urbanization and industrialization. China is now confronted with environmental pollution and ecological deterioration at a critical point, at which economic development in China is limited. Moreover, environmental problems in China have become a lit fuse for social fluctuation beyond pollution problems. The root and background of environmental problems in China, firstly, are its government's lack of understanding of these problems and incorrect economic policies affected by political and ideological prejudice. Secondly, the plundering of resources, 'the principle of development first' which didn't consider environmental sustainability is another source of environmental deterioration in China. In addition, a huge population and poverty in China have increased the difficulty in solving its environmental problems, and in fact have accelerated them. The Chinese government has established many environmental laws and institutions, increased environmental investments, and is enlarging the participation of NGOs and the general public in some limited scale to solve its environmental problems. However, it has not obtained effective results because of the lack of environmental investments owing to the government's limit of the development phase, a structural limit of law enforcement and local protectionism, and the limit of political independency in NGOs and the lack of public participation in China. It seems that China remains in the stage of 'economic development first, environmental protection second', contrary to its catch-phrase of 'the harmony between economic development and environmental protection'. China is now confronted with dual pressure both domestically and abroad because of deepening environmental problems. There are growing public's protests and demonstrations in China in response to the spread of damage owing to environmental pollution and ecological deterioration. On the other hand, international society, in particular neighboring countries, regard China as a principal cause of ecological disaster. In the face of this dual pressure, China is presently contemplating a 'recycling economy' that helps sustainable development through the structural reform of industries using too much energy and through more severe law enforcement than now. Therefore, it is desirable to promote regional cooperation more progressively and practically in the direction of building China's ability to solve environmental problems.