• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.1
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• pp.185-193
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• 2016

Purpose of this study is to classify damaged lands according to the cause of the damage and their influences based on characteristic of the damaged lands in DeMilitarized Zone(DMZ) area, and utilize this study as a fundamental study for establishment of ecosystem restoration system. Literature review and field survey have been conducted to review the damage status of DMZ area. For field survey, first year and second year have been conducted, in which type of the damage has been reviewed in this study. In the result, types of damage have been classified into 6 categories: 'alteration of initial landform', 'loss of surface layer', 'land pollution', 'alteration of soil chemical property', 'decline of vegetation', and 'invasion of foreign species'. Restoration for each damage type is as following. First, for alteration of initial landform, the land is restored to the original landform prior to the damage and connection to surrounding ecosystem is considered. Second, for loss of surface layer, lost surface layer is restored or further loss is prevented with stabilization. Third, for land pollution, source of the pollution is eradicated or self-circulation with purification of polluted land is encouraged. Fourth, for alteration of soil chemical property, soil is restored of its original property with eradication of the pollution source and improvement of soil. Fifth, for decline of vegetation, current vegetation and anticipated alteration in future are considered and number of wild species is to be increased based on structure and characteristic of nearby vegetation. Sixth, for invasion of foreign species, prevention of dominance by risky species and facilitation ecological stability with ecological management are to be considered. Influence according to the cause of damage has occurred in secondary(indirect) influence or simultaneous occurrence of several damage types. Considering all these aspects, when type of the damage is complex, restoration process for each of former mentioned 6 damage types with solitary influence should be considered in unison.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.299-305
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• 2019

As the damage factors of the three­storey stone pagoda of the Bulguksa Temple in Gyeongju could cause a reduction in the historical and artistic value and accelerate the deterioration of the stone, an appropriate solution is needed. The aim of stone conservation is to conserve the original shape and convey originality from the ancestors to their descendants. This procedure includes a record of the condition, being available in the future. In particular, the damage assessment could be used in conservational research, educational data, conservational treatment, and preventive data. As a result of quantitative damage assessment, biological damage indicated 159 %, chemical damage 114 %, and physical damage 16 %. The west direction revealed 95 % because of the amount of sunshine, moisture, and expansion of rock. Complex factors and high range damage were observed on the foundation and body of the pagoda. Since the top of pagoda was restored in the 1970s, the state presented a good condition. By doing this, the number of organisms could be reduced by cleaning and the physical damage could be minimized by bonding. On the other hand, continuous monitoring will be needed because there is a possibility of reforming the damage in the future.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.5
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• pp.217-225
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• 2005

In a power system, an out-of-step condition causes a variety of risk such as serious damage to system elements, tripping of loads and generators, mal-operation of relays, etc. Therefore, it is very important to detect the out-of-step condition and take a proper measure. Several out-of-step detection methods have been employed in relays until now. Most common method used for an out-of-step detection is based on the transition time through the blocking impedance area in R-X diagram. Also, the R-R dot out-of-step relay, the out-of-step prediction method and the adaptive out-of-step relay using the equal area criterion (EAC) and Global Positioning Satellite (GPS) technology have been developed. This paper presents the out-of-step detection algorithm using the time variation of the complex power. The complex power is calculated and the mechanical power of the generator is estimated by using the electrical power, and then the out-of-step detection algorithm which is based on the complex power and the estimated mechanical power, is presented. This algorithm may detect the instant when the generator angle passes the Unstable Equilibrium Point (UEP). The proposed out-of-step algorithm is verified and tested by using Alternative Transient Program/Electromagnetic Transient Program (ATP/EMTP) MODELS.

• Journal of the Korean Society of Safety
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• v.36 no.2
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• pp.94-100
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• 2021

In general, the industrial complex is a place where factories of various industries are concentrated. It is only as efficient as it is designed. However, the risks vary as there are various industries. These features are also associated with various types of disasters. The dangers of natural disasters such as a typhoon, flood, and earthquake, as well as fire and explosions, are also latent. Many of these risks can make stable production and business activities difficult, resulting in massive direct and indirect damage. In particular, decades after its establishment, the vulnerabilities increase even more as aging and small businesses are considered. In this sense, it is significant to assess the vulnerability of the industrial complex. Thus analysing fire and explosion hazards as stage 1 of the vulnerability evaluation for the major potential disasters for the industrial complex. First, fire vulnerabilities were analyzed quantitatively. It is displayed in blocks for each company. The assessment block status and the fire vulnerability rating status were conducted by applying the five-step criteria. Level A is the highest potential risk step and E is the lowest step. Level A was 11.8% in 20 blocks, level B was 22.5% in 38 blocks, level C was 25.4% in 43 blocks, level D was 26.0% in 44 blocks, and level E was 14.2% in 24 blocks. Levels A and B with high fire vulnerabilities were analyzed at 34.3%. Secondly, the vulnerability for an explosion was quantitatively analyzed. Explosive vulnerabilities were analyzed at 4.7% for level A with 8 blocks, 3.0% for level B with 5, 1.8% for level C with 3, 4.7% for level D with 8, and 85.8% for level E with 145. Levels A and B, which are highly vulnerable to explosions, were 7.7 %. Thirdly, the overall vulnerability can be assessed by adding disaster vulnerabilities to make future assessments. Moreover, it can also assist in efficient safety and disaster management by visually mapping quantified data. This will also be used for the integrated control center of the N-Industrial Complex, which is currently being installed.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.85-99
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• 2023

By the social advancement, radiological disaster prevention planning is getting important considering complex disasters as in the Fukushima radiological disaster occurred by a chain of natural disasters. However, it has yet to be suggested the specific prevention plans for the complex disasters in the field of national radiological disaster prevention. This study aims to analyze the types of complex disasters in order to select the ones that are relatively more likely to occur in the domestic environment. It is also to analyze the impact on the radiological disaster prevention by searching damage spread of the classified natural disasters. We provides the necessary criterial for establishing disaster prevention plans through the scenarios for radiological emergency responses based on complex disasters. it is thought that these criteria can help prepare for the worst case scenario and implement effective resident protection.

• Korean Journal of Biological Psychiatry
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• v.2 no.2
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• pp.157-168
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• 1995

The neuropsychiatric sequelae of traumatic brain unjury(TBI) are effects on complex aspect of behavior, cognition and emotional expression. They include psychiatric disorders such as depression, psychosis, personality change, dementia, and postconcussion syndrome. The damage is done not only to the cortex of the brain but also to subcortical and axial structures. The diffuse degeneration of cerebral white mailer is axonal damage that is caused by mechanical forces shearing the neuronal fiber at the moment of impact(diffuse axonal injury, DAI). The DAI and the changed receptor-agonist mechanism ore the most important mechanisms in genesis of neuropsychiatric sequalae by mild TBI. The most important instrument for diagnosis of neuropsychiatric sequalae of TBI is a physician or psychiatrist with experience and knowledge. The most effective therapeutic tool is a professional who understands the nature of the problem.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.10a
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• pp.29-32
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• 1991

It is well known that the fatigue damage process in composite materials is very complicated due to complex failure mechanisms that comprise debounding, matrix cracking, delamination and fiber splitting of laminates. Therefore, the residual strength, instead of a single dominant crack length, is chosen to describe the criticality of the damage accumulated in the sublaminate. In this study, two models for residual strength degradation established by Yang-Liu and Tanimoto-Ishikawa that are capable of predicting the statistical distribution of both fatigue life and residual strength have been investigated and compared. Statistical methodologies for fatigue life prediction of composite materials have frequently been adopted. However, these are usually based on a simplified probabilistic approach considering only the variation of fatigue test data. The main object of this work is to propose a fatigue reliability analysis model which accounts for the effect of all sources of variation such as fabrication and workmanship, error in the fatigue model, load itself, etc. The proposed model is examined using the previous experimental data of GFRP and it is shown that it can be practically applied for fatigue problems in composite materials.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.439-446
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• 1998

Earthquake damage civil engineering structures every year in the world and bridges are no exception. Bridge structures have proven to be vulnerable to earthquake, sustaining damage to substructure and foundation and being totally destroys as superstructures collapse from their supporting elements. The poor seismic performance of bridge structures is surprising in view of the substantial advance made in design and construction for vertical load. Recently, bridge spans have been pushed further than before, alignment has become increasingly complex and aesthetic requirement have been become more demanding. To reduce the seismic force and to improve the safety of the advanced bridges, the bridge bearings which are the substructures and foundations and their connections to the superstructure become more important and critical elements. Therefore, the functions about seismic devices to be using as bridge bearing are discussed.

• Fire Science and Engineering
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• v.3 no.1
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• pp.11-18
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• 1989

The suffering damage of persons and properties from fires has become large sized in modem society that buildings are rapidly higher, denser and more complex. Especially, in the building fires, it is recently the most important issue that the treatment of smoke which is the hardest hindrance in escape. Therefore, as effective exhaust matter of smoke or poisonous gas is connected directly, synthetic, fundamental fire prevention countermeasure must be achieved after mutual connections between architecture and mechanical system and requlations ars sufficiently examinated. From this studies, 1 show the structure computation data which can be applied to smoke venting plan and architectural design for safety after find necessity and point at issue of prevention plan of fires by examinating statistical data about cause and damage situation.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.98-104
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• 2013

The effect of the tool-sheet interaction on formability enhancement in electromagnetic forming is investigated using FEM. A free bulging and a conical forming die with 0.7mm AL1050 sheet are used to evaluate damage evolution based on Gurson-Tvergaard-Needleman plasticity material model. The impact between the tool and sheet results in complex stress states including compressive hydrostatic stresses, which leads to a suppression of void growth and restrain ascending void volume fraction of the sheet. Therefore, the damage suppression due to the tool-sheet interaction can be the main factor contributing to the increased formability in the electromagnetic forming process.