• Journal of Environmental Science International
• /
• v.15 no.1
• /
• pp.33-43
• /
• 2006

Revetment Mattress/Filter is the porous structure filled fillers in meshed structure so that it cail use the fillers of various sizes and form various pores. The porous structure of the Mattress/Filter increases drainage so that it decreases the energy and erosion of flow therefore the tractive force is decreased and the erosion of revetment is mitigated. The filler of Mattress/Filter uses gravels, waste concretes and slags so that the surface is rough and the roughness coefficient increases and the increase of the roughness coefficient decreases flow velocity and tractive force. On the other hand Mattress/Filter and vegetation are combined so that the increase of roughness coefficient and flow velocity still more progress therefore the effect of decrease of tractive force is increased after a few months have passed since the Mattress/Filter is constructed so that the vegetation is developed and be stabilized. The vegetation channel of Mattress/Filter is set tip and the inspection comes into operation by varing flowrate and vegetation spacing to examine these characters of the Mattress/Filter The coefficient of flow velocity U/U*' is decreased exponentially as vegetation esity aH' or $\lambda$ is increased and the coefficient of friction f is increased as vegetation desity aH' is increased but decreased as the coefficient of flow velocity U/U*' is increased. The effective tractive force $F_0$ is decreased exponentially as the vegetation desity aH' is increased. From the inspection the results are obtained that the porous and vegetation structure of the revetment Mattress/Filter system increases the coefficient of friction of revetment so that flow velocity and effective are decreased therefore greatly contributes the stability of the revetment.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.1
• /
• pp.59-66
• /
• 2011

Lifeline Damages induced by earthquake loading brings not only a structure damage but the communication problems by the interruption of various energy utilities such as electric power, gas, and water resources. Earthquake loss estimation systems in USA and Japan, called as HAZUS (Hazard in US) and HERAS (Hazards Estimation and Restoration Aid System), respectively, have been established for the purpose of efficient responding to the earthquake hazard. Sufficient damage records are required to establish these systems. However, there are insufficient data set of damage records obtained from previous earthquakes in Korea. In this study, according to the construction specifications of the pipelines in both Korea and USA, the behavior of both ductile and brittle pipelines embedded in dense sand overlying various soils, such as clay, sand, and gravel were examined with respect to the pipeline characteristics under various earthquake loadings. The applicability of pipeline damage prediction used in HAZUS program to Korea has been investigated.

• Journal of Forest and Environmental Science
• /
• v.14 no.1
• /
• pp.112-127
• /
• 1998

A meeting for Japan Society of Erosion Control Engineering took place, from May 20-21 in Sapporo, Japan, with the presentations of 21 special topics and 185 general papers. Special topics consists of 6 copies on volcanic disaster prevention, 6 copies on the activity report of Earthquake Erosion Control Engineering Society, 5 copies on the management and guidelines of riparian zone and 4 copies on debris disaster occurred in 1997. General papers consists of 10 copies on slope stability, 10 copies on slope failure, 9 copies on earthquake, 41 copies on environmental erosion control, 25 copies on debris flow, 11 copies on warning and refuge, 10 copies on erosion control plan, 11 copies on erosion control project, 10 copies on erosion control facility, 12 copies on volcanic erosion control, 4 copies on revegetation technology, 4 copies on forest hydrology, 4 copies on avalanche, 4 copies on landslide, 18 copies on debris flow and 2 other copies presented by international student. Among the special topics, 5 papers with the titles of the function and structure of riparian zone, the interactive relation of flood and riparian zone, the management method of channel and river forest for controlling debris flow, the forest restoration efforts by native population, the law and social issue for building river riparian zone were presented in the subsection of "The Management and Guidelines of Riparian Zone". Thus, this article summarize and introduce the presented contents which are very important and can be referred to keep environmentally sound-river in the erosion control field.

• Korean Journal of Heritage: History & Science
• /
• v.48 no.1
• /
• pp.24-43
• /
• 2015

This study constitutes an inquiry into the decline of Government Office(官衙) facilities carried out intensively during modern era, focusing on provincial government offices of Jeollabuk-do. There have been several studies of changes in provincial government offices till now, but there have been few studies of government offices of the counties and prefectures(郡縣) during the period of the Japanese Resident-General of Korea and after the National Liberation, temporally and there have still been lacking studies on Jeollabuk-do, spatially. Thus, this study attempts to empirically prove the reasons and the time of the decline of provincial government offices in Jeollabuk-do and the characteristics in the process of decline focusing on modern era. As a result of the study, four factors: demolition, abolition, appropriation and disaster had the most decisive impacts on the decline of government office facilities. Demolition refers to the destruction of government office facilities, and abolition, to the decline and the discontinuation of the operation of the facilities. Appropriation refers to conversion to facilities to meet public functions, and disaster, damage from a typhoon or fire. These factors had already been started from the 1900s, and by the 1930s, most of the government office facilities came to lose their original looks and functions. In the meantime, there was an essential purpose in demolition, the most direct factor in the destruction of the government office facilities in terms of function: that is new construction of public facilities necessary for administration and rule. The existing government office facilities were appropriated, sometimes, but behind that, many cases of demolition of the government office facilities for the new construction of public facilities are found. The appropriation of the government office facilities is divided into educational, administrative, financial and security facilities, and generally, Gaeksa(客舍) and Dongheon(東軒) were used respectively as educational and administrative facilities while their attached facilities were used as financial and public order and security facilities in general. Especially, some government office facilities were utilized as distinctive facilities such as housing or hospital. In the process of appropriation, a lot of modification occurred inside and outside the government office facilities, due to which, the government office facilities gradually declined losing their traditional styles.

• Journal of Korea Water Resources Association
• /
• v.44 no.10
• /
• pp.787-795
• /
• 2011

Extreme water events such as heavy rainfalls due to recent climate change are continually increasing and their scale has also shown an increasing trend. To overcome these natural disasters, this policy study suggests securing lateral river space as an effective method for extreme flood. To support the importance of restoration and expansion of lateral river space, Gumi upstream region of the Nakdong River basin was chosen as a target area and flood reduction analysis of the washland by using LISFLOOD model have been examined. The 500-year frequency flood was simulated for the estimation of possibly occurable flood level and it turns out that the secured lateral river space on the selected site effectively lowers about 0.53 m flood level and reduces the flood damage of the city on the lower reaches of the river. In addition, based on this result, multilateral river space securing plans were compared, and conservation easement and natural disaster insurance were suggested for sustainable and cost-effective alternatives. The costs of land purchase and conservation easement for securing the river space were also compared.

• The Journal of Society for e-Business Studies
• /
• v.20 no.1
• /
• pp.183-199
• /
• 2015

Due to the Four Major Rivers Restoration Project, Nakdong River Estuary Barrage's designed flood quantity has been largely increased, and this has caused to construct several drainage gates at the right side of Eulsukdo island to secure the safety of downstream river area. For successful functioning of Nakdong River Estuary Barrage, such as flood control, disaster prevention, and the securing of sufficient water capacity, drainage gates at the both sides of island have to operate systematically and reliably. To manage this under restricted personnel and resources, we have implemented the IOS (Integrated Operation System) by integrating previous facilities and resources via information and communication technologies. The IOS has been designed to have higher availability and fault tolerance to function continuously even with the partial system's failure under the emergency situation like flood. Operators can use the system easily and acknowledge alarms of facilities through its IWS (Integrated Warning System) earlier. Preparing for Integrated Water Resources Management and Smart Water Grid, the architecture of IOS conformed to open system standards which will be helpful to link with the other systems easily.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.3
• /
• pp.155-160
• /
• 2018

The unmanned aerial vehicle (UAV) is used in various fields, such as land surveying, facility management, and disaster monitoring and restoration because it has low operational costs, fast data acquisition, and can generate a digital surface model (DSM). Recently, the UAV has been applied to process management in construction projects. Construction projects are widely distributed not only in urban areas but also in mountainous areas and rural areas where people are rarely in traffic or in vehicles. Projects range from a few hundred meters to several kilometers long. In order to perform a reconnaissance survey, a surveying method using a global positioning system (GPS) or a total station has mainly been used. However, these methods have a disadvantage in that a lot of time is required for data acquisition. This study's purpose is to evaluate the usability of a UAV DSM for surveying a construction area. Data was acquired using the UAV and a three-dimensional (3D) laser scanner, and the DSM of the construction site was created through data processing. The UAV DSM showed accuracy to within 30 cm based on the 3D laser scanner data, and a process comparison between the two work methods was able to present the usability of the UAV DSM in the field of construction surveying. Future utilization of the UAV DSM is expected to greatly improve the efficiency of work in construction projects.

• Journal of Wetlands Research
• /
• v.13 no.1
• /
• pp.1-11
• /
• 2011

A chronic drought stress has been imposed during non-rainy season(from winter to spring) since 1990s. We faced the most significant water crisis in 2001, and the drought was characterized by sultry weather and severe drought on a national scale. It has been widely acknowledged that the drought related damage is 2-3 times serious than floods. In the list of the world's largest natural disaster compiled by NOAA, 4 of the top 5 disasters are droughts. And according to the analysis from the NDMC report, the drought has the highest annual average damage among all the disasters. There was a very serious impact on the economic such as rising consumer price during the 2001 spring drought in Korea. There has been flood prevention measures implemented at national-level but for mitigation of droughts, there are only plans aimed at emergency (short-term) restoration rather than the comprehensive preventive measures. In addition, there is a lack of a clear set of indicators to express drought situation objectively, and therefore it is important and urgent to begin a systematic study. In this study, a nonstationary downscaling model using RCM based climate change scenario was first applied to simulate precipitation, and the simulated precipitation data was used to derive Standardized Precipitation Index (SPI). The SPI under climate change was used to evaluate the spatio-temporal variability of drought through principal component analysis at three different time scales which are 2015, 2045 and 2075. It was found that spatio-temporal variability is likely to modulate with climate change.

• Journal of Conservation Science
• /
• v.36 no.5
• /
• pp.333-338
• /
• 2020

Dye markers are used in the study of subterranean termites to determine colony territories and population sizes. Dyes not only allow the study of termite biology, but can also be used for control purposes. Although Reticulitermes speratus kyushuensis causes damage to wooden historical properties in Korea, the dye markers have not been applied. Therefore, we evaluated the applicability of Nile Blue A dye for R. s. kyushuensis. Filter papers dyed with concentrations of 0.05%, 0.10%, and 0.25% (w/w) were each fed to termite populations through a no-choice feeding test for 1, 3, or 7 days. After 4 weeks, the survival rate, dyeing rate, and maintenance of dyeing were recorded. The results showed high survival rates with lower dye concentrations and shorter feeding periods. Among the combinations of concentrations and days, high survival rates, dyeing rates, and dyeing maintenance periods were found at concentrations of 0.05% and 0.10% for 3 days of feeding. These maximized the survivorship and visibility. The results from the current study can be applied to investigate the ecology and control of R. s. kyushuensis in both the laboratory and field.

• Journal of the Korean Geosynthetics Society
• /
• v.16 no.2
• /
• pp.23-33
• /
• 2017

Due to the rapid development of cities, densities and heights of urban structures are increased, and much larger and more underground spaces are being developed accordingly. Increasing development of underground spaces has induced more ground sinks and underground cavities. Therefore, safety of people is threatened by potential ground collapses and possible accidents, which may result from underground cavity. To actively respond against potential danger of ground sink, evaluation of existing cavity grade and development of recovery procedure are important. There exists the ground sinking management grade system of expressway developed as local standards in Japan. Recently, ground sinking management grade system of Seoul was developed with consideration of road and asphalt conditions. In this study, 209 underground cavities of ${\bigcirc}{\bigcirc}$ area were explored and their cavity shapes and grades were evaluated based on both ground sinking management grade systems of Japan and Seoul. Comparison is made between cavity grades evaluated based on both grading systems from Japan and Seoul. As a result of comparative analysis, the conservatively-estimated cavity grades requiring emergency restoration based on the Japanese management grade system of expressway result from neglection of layer thickness of surface pavement, considering only width and cover depth of a cavity.