• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.97-104
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• 2010

The purpose of this study is to evaluate sediment yield reduction under various field slope conditions with rice straw mat. The Vegetative Filter Strip Model-W (VFSMOD-W) and Soil and Water Assessment Tool (SWAT) were used for simulation of sediment yield reduction effect of rice straw mat. The Universe Soil Loss Equation Practice factor (USLE P factor), being able to reflect simulation of rice straw mat in the agricultural field, were estimated for each slope with VFSMOD-W and measured soil erosion values under 5, 10, and 20 % slopes. Then with the regression equation for slopes, USLE P factor was derived and used as input data for each Hydrological Response Unit (HRU) in the SWAT model. The SWAT Spatially Distributed-HRU (SD-HRU) pre-processor module was utilized, moreover, in order to consider spatial location and topographic features (measured topographic features by field survey) of all HRU within each subwatershed in the study watershed. Result of monthly sediment yield without rice straw mat (Jan. 2000 - Aug. 2007) was 814.72 ton/month, and with rice straw mat (Jan. 2000 - Aug. 2007) was 526.75 ton/month, which was reduced as 35.35 % compared without it. Also, during the rainy season (from Jun. to Sep. 2000 - 2007), when without vs. with rice straw mat, monthly sediment indicated 2,109.54 ton and 1,358.61 ton respectively. It showed about 35.60 % was reduced depending on rice straw mat. As shown in this study, if rice straw mat is used as a Best Management Practice (BMP) in the sloping fields, rainfall-driven sediment yield will be reduced effectively.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.1
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• pp.46-53
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• 2010

A Compton X-ray backscatter technique has been developed to quantitatively assess impact damage in quasi-isotropic laminated composites made by a drop-weight tester. X-ray backscatter imaging system with a slit-type camera is constructed to obtain a cross-sectional profile of impact-damaged laminated composites from the electron-density variation of the cross section. A nonlinear scattering model based on Boltsman equation is introduced to compute Compton X-ray backscattering field for the defect assessment. An adaptive filter is also used to reduce noises from many sources including quantum noise and irregular distributions of fibers and matrix in composites. Delaminations masked or distorted by the first delamination are detected and characterized effectively by the Compton X-ray backscatter technique, both in width and location, by application of error minimization algorithm.

• Journal of Environmental Impact Assessment
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• v.9 no.3
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• pp.163-176
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• 2000

The purpose of this study is to analyze the pollutant loads and its distribution, and to suggest the management of nonpoint sources in Daechong Reservoir. The loads from point and nonpoint sources such as population, industry, livestock and land use were calculated per stream or river with topography(1:25,000) of the watershed of Daechong Reservoir. The generating pollutant loads were obtained through multiplication of pollutant sources by generating pollutant quantity per unit pollutant source. The effluent point sources loads is defined as loads from wastewater treatment facilities such as domestic, industrial and livestock wastewater treatment facilities, which were calculated through multiplication of effluent flowrates by water quality constituents concentration. Untreated point sources loads were estimated to be 35 % of total point sources loads. The effluent nonpoint sources pollutant loads were obtained through the multiplication of generating nonpoint sources loads by effluent ratios based on previous studies. The effluent nonpoint sources loads have the ratio of 26.2% of total BOD effluent loadings, 20.1% of total T-N effluent loadings, and 10.5% of total T-P effluent loadings. For the reduction of nonpoint sources loads in Daechong Reservoir, silviculture, artificial wet land, and grassed waterways could be applied. And untreated livestock waste scattered can result in nonpoint loadings, so required the livestock wastes treatment facilities and purifying facilities together with the management of shed, pasture, livestock waste storage site and composting site. Finally, remote sensing and GIS should be applied to the identification of distribution of water quality, watershed, the location and scale of nonpoint sources, effluent process during rainfall, for more detailed analysis of nonpoint sources.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.3
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• pp.91-99
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• 2012

Jinju city is operating by selecting 8 places as the flood inundation risk area and by designating shelters on this area targeting districts damaged by typhoon and heavy rain, in the past. This study selected the research area as Nabul district and Sangpyeong district where are located in the town and that has high population density out of districts with inundation risk. The network analysis of GIS was applied to the suitability assessment on location of shelter by calculating the moving speed and the arriving time after dividing it into children, general adults, and aged people in consideration of the evacuation condition in inundation disaster. As a result, it was indicated that optimal evacuation plan time for children and aged people exceeded in getting to the shelter because of evacuation time excess and that even general adults outrun the prescribed evacuation time in some districts. Accordingly, a problem for evacuation time was improved by additionally designating 1-2 shelters to existing shelters in Nabul and Sangpyeong districts. A countermeasure is needed to reduce life and property damage in disaster occurrence by implementing the evacuation warning and the age-based evacuation plan more specifically in the future.

• Structural Engineering and Mechanics
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• v.32 no.2
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• pp.193-212
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• 2009

The resilience of a city confronted with a terrorist bomb attack is the background of the paper. The resilience strongly depends on vital infrastructure and the physical protection of people. The protection buildings provide in case of an external explosion is one of the important elements in safety assessment. Besides the aspect of protection, buildings facilitate and enable many functions, e.g., offices, data storage, -handling and -transfer, energy supply, banks, shopping malls etc. When a building is damaged, the loss of functions is directly related to the location, amount of damage and the damage level. At TNO Defence, Security and Safety methods are developed to quantify the resilience of city infrastructure systems (Weerheijm et al. 2007b). In this framework, the dynamic response, damage levels and residual bearing capacity of multi-storey RC buildings is studied. The current paper addresses the aspects of dynamic response and progressive collapse, as well as the proposed method to relate the structural damage to a volume-damage parameter, which can be linked to the loss of functionality. After a general introduction to the research programme and progressive collapse, the study of the dynamic response and damage due to blast loading for a single RC element is described. Shock tube experiments on plates are used as a reference to study the possibilities of engineering methods and an explicit finite element code to quantify the response and residual bearing capacity. Next the dynamic response and progressive collapse of a multi storey RC building is studied numerically, using a number of models. Conclusions are drawn on the ability to predict initial blast damage and progressive collapse. Finally the link between the structural damage of a building and its loss of functionality is described, which is essential input for the envisaged method to quantify the resilience of city infrastructure.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.275-283
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• 2011

The purpose of this study is to investigate the performance status of the ligal examination of risk factors of musculoskeletal disorders(MSDs). The study was based on in-depth interviews with the persons in charge of the examination in 63 sampled companies, which are various in location, type of industry and size. The interviews were carried out based on detail questions as well as a predefined checklist. The main findings are as follows: 1) More than half of the companies did not properly comply with the laws in performing the examination of MSDs risk factors; 2) In about 60% of the companies, the examination has been carried out by their own persons; 3) 38% of the companies conducting the survey of musculoskeletal symptoms did not diagnosed musculoskeletal symptoms based on the survey; 4) Most companies performed the prevention activities for MSDs such as education/training, stretching, etc.; 5) It was revealed that the 11 high-risk tasks were not considered to be properly defined by the people in the industries, which results in some difficulties such as ambiguity in defining the 11 tasks and unit tasks; 6) The period of the examination of risk factors, classification of periodic and occupational examinations and legalization of employers' obligation for preventing MSDs are considered to be acceptable or desirable, while it was pointed out that regulations for the method of the risk assessment and the person who in charge of the examination need to be modified.

• Spatial Information Research
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• v.19 no.2
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• pp.29-36
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• 2011

This study performed quantitative assessment of the performance of adjustment models by a-priori analysis of the statistics of the surface parameter estimates against modeling factors. Lidar, airborne imagery, and SAR imagery have been used to acquire the earth surface elevation, where the shape properties of the surface need to be determined through neighboring observations around target location. In this study, parameters which are selected to be estimated are elevation, slope, second order coefficient. In this study, several factors which are needed to be specified to compose adjustment models are classified into three types: mathematical functions, kernel sizes, and weighting types. Accordingly, a-priori standard deviations of the parameters are computed for varying adjustment models. Then their corresponding confidence regions for both the standard deviation of the estimate and the estimate itself are calculated in association with probability distributions. Thereafter, the resulting confidence regions are compared to each other against the factors constituting the adjustment models and the quantitative performance of adjustment models are ascertained.

• Journal of Environmental Impact Assessment
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• v.19 no.2
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• pp.127-140
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• 2010

This study investigates the relation between the location of a habitat and the ecological connections according to the habitat type in the riparian zone at the Nonsan Stream and Yanghwa Stream. Stream habitat is classified into nine types for the aquatic insects and fish. For vegetation and birds, habitat is classified into two types of medium-scale streams, including both physical and chemical streams are analyzed accordingly. Nowadays, The fundamental goal of the river environment restoration enterprise is the rehabilitation or the restoration of the characteristic the river scenic or environment. For instance, The Channel habitats which has physical nature environment such as flat, speedy rapids, or closed-channel wetland, pool are constructed by artificial, Consequently, make them autogenesis smoothy eco-environment. However, the river environment are controlled not only physical environment, but it also need reasonable the quality of the water to compose smoothly. Finally, understanding what influence are effecting on physical habitat environment which are made by natural factors to water quality are very important factor for the river environment restoration enterprise Therefore, In this research, we are targeting to a basin to investigate the environment of the physical channel habitat and evaluate the changing of the water quality. This results will be a important characteristic that can judge the physical habitat and reciprocality connected to the water quality or adequacy of restoration technology. Therefore in this study, as a step to quantify functions and values of habitats and definite factors to perform habitat, we selected a representative stream of sand-stream, gravel-stream to classify habitat characteristics and quantified the physical, chemical, biological characteristics.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.1
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• pp.11-16
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• 2020

The rotational stability of an interlocking caisson breakwater was studied. Using the analytical solution for the linear wave incident to the infinite breakwater, the phase difference effect of wave pressures in the direction of the breakwater baseline is considered, and Goda's wave pressure formula in the design code is adopted to consider the nonlinearity of the design wave. The rotational safety factor of the breakwater was defined as the ratio of the rotational frictional resistance moment due to caisson's own weight and the acting rotational moment due to the horizontal and vertical wave forces. An analytical solution for the rotational center point location and the minimum safety factor is presented. Stability assessment formula were proposed to be applicable to all design wave conditions used in current port and harbor structure design such as regular waves, irregular waves and multi-directional irregular waves.

• Journal of Chest Surgery
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• v.54 no.1
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• pp.59-64
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• 2021

Background: Diaphragmatic injuries following blunt or penetrating thoraco-abdominal trauma are rare, but can be life-threatening. Rib fractures are the most common associated injury in patients with a traumatic diaphragmatic injury (TDI). We hypothesized that the pattern of rib fracture injuries could dictate the likelihood of acute TDIs. Methods: A retrospective study was carried out between April 2014 and October 2018 to analyze patients with TDIs and rib fractures at a major trauma center in London, United Kingdom. Results: Over the study period, 1,560 patients had rib fractures, of whom 14 had associated diaphragmatic injuries. Left-sided diaphragmatic injuries were found in 8 patients (57%). A significant proportion of the rib fractures were located posterolaterally (44.9%). The highest frequency of fractures was found in ribs 5-10, which accounted for 74% of all the fractures. Ten patients underwent surgery, of whom 7 were diagnosed with a diaphragmatic injury intraoperatively after video-assisted thoracoscopic surgery assessment of the pleural cavity. Two patients died due to severe injuries of other organs and the remaining 2 patients were managed conservatively. Conclusion: Our series of patients demonstrates a relationship between significant rib fractures and diaphragmatic injuries in trauma patients, and the diagnostic difficulties in identifying the condition. We found that the location of the rib fractures and the pattern of injury in patients with TDIs were much lower and posterolateral in the chest wall without a preference for laterality. We suggest using a thoracoscope in patients undergoing chest wall surgery post-trauma to aid in diagnosing this condition.