• The Korean Journal of Air & Space Law and Policy
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• v.26 no.2
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• pp.239-258
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• 2011

Space debris mitigation has become an international custom for international space activities. IADC and COPUOS adopted a Guideline on Space Debris Mitigation. Two Guidelines provided that member states or international organization shall establish a national mechanism to mitigate space debris. China has made progress in legislation on space debris mitigation and management system. It establised a fundamental framework on the legislative mechanism on space debris mitigation and managemental mechanism on space debris mitigation. In order to further improve the national mechanism on space debris mitigation, it is essential for China to strenghen legislation on space activities and specify the duties of management administrates.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1271-1274
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• 2009

One of the landslide, Debris flow means flow mixed of rocks, gravels, sand and soil with water. Debris flow occurred in summer by passed the rainy season and typhoon. Especially, Localized heavy rain derived from abnormal weather caused debris flow independent of season. It is increase to collapse of house, bridge, roads by debris flow but countermeasure studies about occurrence cause, movement pattern, damage scale about debris flow are insufficient. This study performed debris flow model experiment using dry material and calculated shock force predicted debris flow occurrence.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.815-829
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• 2008

Debris flows are a natural hazard which looks like a combination of flood, land and rock slide. Large rainfall in July 2006 produced several large scale debris flows and many small debris flows that resulted in loss of life and considerable property and railway damage, as was widely reported in the national media. The hazard "debris flow" is still insufficiently researched. Furthermore debris flows are very hard to predict. Flexible Ring net barriers are multi-functional mitigation devices commonly applied to rock fall or floating wood protection in floods, snow avalanches and also mud flows or granular debris flows, if properly dimensioned for the process or processes for which they are intended. Overtopping of the barriers by debris flows and sediment transport is possible, supporting the design concept that a series of barriers may be used to stop volumes of debris larger than are possible using only one barrier. The future for these barrier concepts looks promising because these barriers represent the state of art for such applications and are superior to many other available options.

• Nuclear Engineering and Technology
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• v.15 no.4
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• pp.256-266
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• 1983

An evaluation of containment transient pressure due to the particulate debris/water/concrete interaction under severe accident conditions is presented for a pressurized water reactor with a large dry containment building. A particulate debris/water/concrete model is developed and incorporated into the MARCH computer code. Comparisons with the existing MARCH molten debris/concrete model were performed for the TMLB' and S$_2$D sequences. The results yield a much slower concrete decomposition rate and release less gases into the containment atmosphere. Contrary to the molten debris model, the particulate debris model exhibits a strong interaction with water and causes a higher containment pressure. The effect of gas influx on the debris bed heat transfer was found to be insignificant.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.6
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• pp.507-516
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• 2015

Debris flow is a representative natural disaster in Korea and occurs frequently every year. Recently, it has caused considerable damage to property and considerable loss of life in both mountainous and urban regions. Therefore, It is necessary to estimate the scope of damage for a large area in order to predict the debris flow. A response model such as the random walk model(RWM) can be used as a useful tool instead of a physics-based numerical model. RWM is a probability model that simplifies both debris flows and sedimentation characteristics as a factor of slopes for a subjective site and represents a relatively simple calculation method compared to other debris flow behavior calculation models. Although RWM can be used to analyzing and predicting the scope of damage caused by a debris flow, input variables for terrain conditions are yet to be determined. In this study, optimal input variables were estimated using DEM generated from the Aerial Photograph and LiDAR data of Mt. Umyeon, Seoul, where a large-scale debris flow occurred in 2011. Further, the deposition volume resulting from the debris flow was predicted using the input variables for a specific area in which the deposition volume could not be calculated because of work restoration and the passage of time even though a debris flow occurred there. The accuracy of the model was verified by comparing the result of predicting the deposition volume in the debris flow with the result obtained from a debris flow behavior analysis model, Debris 2D.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.3
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• pp.45-53
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• 2002

This investigation is performed to prepare reducing method drained floating debris from the river This paper is present an investigation result of the marine debris characteristics that drained from korea 4 big river(han river, kum river, youngsan river, nakdong river) during July and August. A mount of floating debris different with rainfall. Short heavy rain like as 150mm/day floating debris drained lower, almost floating debris drained when a flooding cause by continuance heavy rain. Floating debris draining is not continuance, but concentrated on a flooding. All debris is do not drained ocean, a lot of debris accumulated riverside. Floating debris is drained with plant and configuration is similar with other river. But, the component ratio is different, so that, to Prepare removing method for floating debris consider that effect of plant debris.

• Journal of the Korean Geotechnical Society
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• v.29 no.5
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• pp.19-27
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• 2013

Most of the landslides induced by rainfall in summer rainy season appear in the type of debris flow. Debris flow gives a lot of economic losses and human casualties due to high moving velocity and volume of debris flow. In order to analyze movement and deposition characteristics of debris flow, numerical analysis using FLO-2D program was conducted with various viscosities and yield stresses. As a result of numerical analysis, velocity and runout distance of debris flow decreased as its viscosity increased due to resisting force between particles of debris flow. Consequently, flow depth of debris flow increased and impact force decreased. Yield stress of debris flow affected its initiation and deposition characteristics. As yield stress increased, runout distance of debris flow decreased and its impact force increased. Based on the results of numerical analysis, it was found that velocity of debris flow mainly depended on viscosity, while deposition characteristics (runout distance, deposition width, deposition area) of debris flow depended on both viscosity and yield stress.

• Journal of the Korean Society of Safety
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• v.33 no.4
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• pp.84-89
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• 2018

The number of landslides has increased since the 2000s due to the increased frequency of heavy rainfall caused by abnormal weather. A variety of debris flow prevention facilities have been installed as a countermeasure against this problem. However, it is not easy to evaluate the efficiency of debris flow prevention structures except for the structures with constant volume such as the erosion dam, because the other structures are limited to be reproduced in simulation program for debris flow. Therefore, the methods by which the debris flow prevention structures were modeled were proposed, and the efficiency of four prevention structures installed in Baekyang Mt. in Busan was evaluated with UDS, which accuracy had been verified, using these methods. The initial amount of debris flow was determined based on landslide which occurred in 2014, and specifications of the complex retaining walls around the settlements were measured and applied modeling for terrain. The numerical results showed that the efficiency of debris flow prevention structures could be quantitatively presented. Among the debris flow prevention structures installed in Baekyang Mt., prevention structure of barrier type for debris flow was the most efficiency and debris flow prevention device was the lowest efficiency when the only depth of debris was evaluated. It seems that this study is meaningful to propose the methods which were used to model the debris flow prevention structures that could not be reproduced in most 2D debris flow numerical analysis programs. If precise verification of the presented methods is carried out, it will be possible to provide clear criteria for the efficiency evaluation method of disaster prevention structures.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.273-280
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• 2008

Debris flow has been considered as one of the major natural hazards and possesses tens to hundreds times higher destructive potential than that of slope failure. In the past 5 years, its occurrence frequency was and is likely to increasing due to the global warming. Although various methods such as basin vegetation or structural dams can be implemented to counter measure the debris flow, these methods are not always the right answer to the problem when magnitude of debris flow is far bigger than could be defended. Land use regulations to avoid the hazard or early debris flow warning system to evacuate the expected inundated area can be more economical and practical actions for those cases. In this study, an early debris flow warning system composed of rainfall measuring device, debris flow sensing device and video camera is introduced. The system is designed to issue the warning when rainfall threshold is exceeded or debris flow is sensed by sensing device. Developed monitoring system can be used to cope promptly with the debris flow risk.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.9
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• pp.845-857
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• 2015

Recently, deterioration of space environment due to space debris is getting a lot of international attention and advanced countries in space technology are willing to comply with their space debris mitigation guidelines. With these efforts to reduce the number of space debris, active space debris removal technology means to try and to get rid of space debris directly. In this paper, the background and recent status on active space debris removal technologies of overseas agencies are presented. Also, cases of technology development and patents are introduced. Thus, this paper can be usefully referred to by the colleagues who are willing to start the research and development of active space debris removal technologies.