• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.17-25
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• 2017

Owing to recent climate change, the scale of rainfall tends to increase gradually and the risk of flooding has increased. Therefore, the importance of improving the levee management and disaster response is increasing. Levee management in Korea is carried out at the level of damage recovery after the occurrence of damage. Therefore, it is necessary to develop a technology for predicting and managing the levee safety with proactive river management. In this study, a method to estimate the safety against erosion and overflow was suggested. A map of levee safety that can be used as basic data is presented by displaying the levee safety on the map. The levee erosion safety was calculated as the ratio of the internal and external force for each shore type. The levee overflow safety was calculated as the ratio of the maximum conveyance and design flood. The maximum conveyance was a discharge when the level of the river was equal to the level of the levee crown. The levee safety was classified into 5 grades: very safe, safe, normal, dangerous, and very dangerous. As a research area from downstream of Nam River Dam to Nakdong River Junction, the levee safety against erosion and overflow was estimated for all levees and all cross-sections of the river. The levee safety was displayed on a map using GIS. Through the levee safety map as a result of this study, the levee safety can be observed intuitively. Using the levee safety map, a maintenance plan for a river can be easy to build. This levee safety map can be used to help determine the priority of investment for efficient budget used.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.2
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• pp.104-110
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• 1997

Increase of marine transpotation in coastal area frequently yields oil spill accidents due to collision or grounding of oil tankers, which affects great deal of damages on ocean environments. Exact prediction of oil pollution area in time domain, which is called oil map, is very important for effective and efficient oil recovery and minimization of environmental damage. The prediction is carried out by considering the two distinct processes which are initial diffusion on the still water surface and advection due to tide, wind wave induced surface currents. In the present paper, only the initial diffusion is dealt with. Somewhat new simulation model and its numerical scheme are proposed to predict it. Simple diffusion experiment is also carried out to check the validity of the present method. Furthermore, some example simulations are performed for virtual oil spill accident. Quite realistic oil map including oil thickness distributions can be obtained by the present model.

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.36-51
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• 2000

Almost every year, Korean suffered from the repetitive natural disasters such as typhoons and floods. During last 10 years, Korea experienced annual average of $50 million property damages caused by inundation. To estabilish the flood disaster counter plan, knowledge for flood damage causes based on the field investigations of inundated area is required. The field investigations is focused on technique to document and analyze the meteorological conditions leading to torrential rains, the causes and patterns of flooding, the performance of flood control structures in affected areas, the extent damages and the effectiveness of local emergency response and recovery actions. We did comparative analysis of field investigation techniques. As a major goal of flood hazard map design, one of non structural disaster countermeasures, it was expected to reduce flood damage losses by requiring local governments to implement land-use regulation that would result in safe building practices in flood hazard areas. This requires local governments to develop flood hazard maps to assess how to manage particularly vulnerable floodplain areas. In this study we suggested a design manual and the management system of flood hazard map.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1387-1390
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• 2008

In a wireless network, handover latency is very important in supporting user mobility with the required quality of service (QoS). In view of this many schemes have been developed which aim to reduce the handover latency. The Hierarchical Mobile IPv6 (HMIPv6) approach is one such scheme which reduces the high handover latency that arises when mobile nodes perform frequent handover in Mobile IPv6 wireless networks. Although HMIPv6 reduces handoff latency, failures in the mobility anchor point (MAP) results in severe disruption or total disconnection that can seriously affect user satisfaction in ongoing sessions between the mobile and its correspondent nodes. HMIPv6 can avoid this situation by using more than one mobility anchor point for each link. In [3], an improved Robust Hierarchical Mobile IPv6 (RH-MIPv6) scheme is presented which enhances the HMIPv6 method by providing a fault-tolerant mobile service using two different MAPs (Primary and Secondary). It has been shown that the RH-MIPv6 scheme can achieve approximately 60% faster recovery times compared with the standard HMIPv6 approach. However, if mobile nodes perform frequent handover in RH-MIPv6, these changes incur a high communication overhead which is configured by two local binding update units (LBUs) as to two MAPs. To reduce this communication overhead, a new cost-reduced binding update scheme is proposed here, which reduces the communication overhead compared to previous schemes, by using an increased number of MAP switches. Using this new proposed method, it is shown that there is a 19.6% performance improvement in terms of the total handover latency.

• Journal of Korean Neurosurgical Society
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• v.38 no.5
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• pp.331-337
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• 2005

Objective : The purpose of this study is to identify correlations between diffusion tensor imaging[DTI] and motor improvement by quantifying and visualizing the corticospinal tract on DTI to predict motor impairment in patients with hypertensive intracerebral hemorrhage[ICH]. Methods : Fifteen normal subjects and 7 patients with hypertensive ICH were examined and the latter were treated surgically. DTI was performed with a 3.0 T MRI. The region of interest[ROI] from the posterior limbs of both internal capsules was measured on a fractional anisotropy[FA] map, and the ratios of ROIs were calculated. Tractography, 3-dimensional DTI was then constructed. Motor impairment was assessed on admission and 2weeks after stroke by the Motricity Index[MI]. The FA ratio, tractography and score on MI were analyzed for correlations. Results : The FA ratio from the initial DTI did not show a linear correlation with motor impairment. However, after 2weeks, patients with high FA ratios showed high degrees of motor recovery, regardless of the initial severity, and patients with low FA ratios showed low recovery rates. Otherwise, a relationship between the amount of hematoma and the degree of motor recovery could not be determined. On tractography, injury of the corticospinal tract could be visualized and estimated 3-dimensionally. Conclusion : FA ratio analysis and tractography constructed from DTI may be useful in understanding corticospinal tract injury and in predicting the recovery from motor impairment in patients.

• Journal of Korean Neurosurgical Society
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• v.62 no.2
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• pp.153-165
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• 2019

Objective : Spinal cord injury (SCI) is a very serious health problem, usually caused by a trauma and accompanied by elevated levels of inflammation indicators. Stem cell-based therapy is promising some valuable strategies for its functional recovery. Nestin-positive progenitor and/or stem cells (SC) isolated from pancreatic islets (PI) show mesenchymal stem cell (MSC) characteristics. For this reason, we aimed to analyze the effects of rat pancreatic islet derived stem cell (rPI-SC) delivery on functional recovery, as well as the levels of inflammation factors following SCI. Methods : rPI-SCs were isolated, cultured and their MSC characteristics were determined through flow cytometry and immunofluorescence analysis. The experimental rat population was divided into three groups : 1) laminectomy & trauma, 2) laminectomy & trauma & phosphate-buffered saline (PBS), and 3) laminectomy+trauma+SCs. Green fluorescent protein (GFP) labelled rPI-SCs were transplanted into the injured rat spinal cord. Their motilities were evaluated with Basso, Beattie and Bresnahan (BBB) Score. After 4-weeks, spinal cord sections were analyzed for GFP labeled SCs and stained for vimentin, $S100{\beta}$, brain derived neurotrophic factor (BDNF), 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase), vascular endothelial growth factor (VEGF) and proinflammatory (interleukin [IL]-6, transforming growth factor $[TGF]-{\beta}$, macrophage inflammatory protein [MIP]-2, myeloperoxidase [MPO]) and anti-inflammatory (IL-1 receptor antagonis) factors. Results : rPI-SCs were revealed to display MSC characteristics and express neural and glial cell markers including BDNF, glial fibrillary acidic protein (GFAP), fibronectin, microtubule associated protein-2a,b (MAP2a,b), ${\beta}3$-tubulin and nestin as well as anti-inflammatory prostaglandin E2 receptor, EP3. The BBB scores showed significant motor recovery in group 3. GFP-labelled cells were localized on the injury site. In addition, decreased proinflammatory factor levels and increased intensity of anti-inflammatory factors were determined. Conclusion : Transplantation of PI-SCs might be an effective strategy to improve functional recovery following spinal cord trauma.

• Journal of Life Science
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• v.19 no.5
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• pp.625-632
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• 2009

The purpose of this study was to examine the effect of exercise training on nitric oxide (NO) levels, mean arterial pressure (MAP), blood pressure (BP), and heart rate (HR) in college students. 5 subjects were randomly assigned to two experimental groups; an aerobic training group (ATG) and a resistance training group (RTG). In aerobic training, based on measured maximum oxygen consumption rate, 70% exercise intensity was applied and conducted for 60 min. In resistance training, 70% of 1-RM was performed for 90 min. Blood sampling was conducted 3 times during resting state, post-exercise, and after 30 minutes of recovery. The results are as followed. For the post training values of $VO_2max$, % body fat and MAP, there were significant differences in the ATG compared to pre training (p<0.05). However, there were no differences in the RTG between pre and post training. NO increased post training, during rest and at the end of exercise compared to pre training in the ATG (p<0.05). Also, the HR decreased in post training at the end of exercise (p<0.05), however, there were no significant differences in SBP and DBP between pre and post training in the ATG. The HR, SBP and DBP did not change at all in post training compared to pre training in the RTG. In conclusion, an increase in the production of Nitric Oxide (NO) concentration and $VO_2max$, decrease of body fat% and physiological variables (HR, BP, MAP) were shown to be more effective in aerobic training (AT) than resistance training (RT).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.6
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• pp.35-50
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• 2017

This study is to see the recovery effect of the Deltacon method by investigating the amount of sand deposition, the topographical cross section and the vegetation structure; and to derive the effective recovery method of coastal erosion area. The target areas of this study include Jinri coastal dune, Bajireum coastal dune and Seopori coastal dune in Deokjeok-do Island, Ongjin-gun, Incheon. In order to assess the current status of the coastal erosion area recovery, the soil profile structure map was prepared on the site and then the amount of sand deposition within 1m was calculated indoors. The vegetation recovery status of the costal erosion area was assessed via the analyses of the topographical profile structure and the plant community structure, and we aim to derive the effective recovery plan of the Deltacon method with the results. With the Deltacon method, structures with ductile material, special non-woven fabric bags filled with soil and vegetation can be performed therefore the structuralstability and prevention of sand erosion can be achieved. The amounts of sand deposition of Bajireum coastal dune, Seopori costal dune and Jinri costal dune were calculated $0.98{\sim}2.54m^3$, $1.02{\sim}2.96m^3$, and $0.27{\sim}0.75m^3$, respectively, and it is considered that the costal erosion recovery is actively performed for Bajireum costal dune and Seopori costal dune. The analysis results of vegetation structures by topography show that the installation of the send collecting net in steep areas has been highly effective and the Deltacon-constructed target areas have been restored to vegetation and the costal dune, which is similar to the natural dune. The investigation of the plant community structure in Deokjeok-do Island costal dune, Incheon displayed similar research results of the existing costal dune flora and confirmed the emergence of Lathyrus japonicus, Carex kobomugi, Elymus mollis, Vitex rotundifolia, and Calystegia soldanella and others. In order to carry out further effective recovery with the Deltacon method, improvements to rootage of herbaceous vegetation are needed in areas without foredune herbaceous vegetation, and continuos maintenance & management monitoring of connected windbreak forest to costal dunes are also necessary.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.3 no.2
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• pp.65-71
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• 2017

To assess the effects of filter and reconstruction of Cu-64 PET data on Siemens scanner, the various reconstruction algorithm with various filters were assessed in terms of spatial resolution, non-uniformity (NU), recovery coefficient (RC), and spillover ratio (SOR). Image reconstruction was performed using filtered backprojection (FBP), 2D ordered subset expectation maximization (OSEM), 3D reprojection algorithm (3DRP), and maximum a posteriori algorithms (MAP). For the FBP reconstruction, ramp, butterworth, hamming, hanning, or parzen filters were used. Attenuation or scatter correction were performed to assess the effect of attenuation and scatter correction. Regarding spatial resolution, highest achievable volumetric resolution was $3.08mm^3$ at the center of FOV when MAP (${\beta}=0.1$) reconstruction method was used. SOR was below 4% for FBP when ramp, Hamming, Hanning, or Shepp-logan filter were used. The lowest NU (highest uniform) after attenuation & scatter correction was 5.39% when FBP (parzen filter) was used. Regarding RC, 0.9 < RC < 1.1 was obtained when OSEM (iteration: 10) was used when attenuation and scatter correction were applied. In this study, image quality of Cu-64 on Siemens Inveon PET was investigated. This data will helpful for the quantification of Cu-64 PET data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.60-64
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• 2013

Water injection pump produced the 1st oil well through the high pressure after the Deep water oil well drilling. After finish the work it is hard to produce only using itself pressure due to low pressure. Therefore it can be increased recovery factor through the injection seawater of high pressure. Is the key equipment used in the marine plant and it is developing at many industries. In this paper, Analyze changes in the natural frequency due to the stiffness of the bearing. Analyze the critical speed of the natural frequency due to the change of operation speed. And evaluate the Stability. And then analyze the displacement and clearance through the unbalance response this way has contributed to the reliability of the developing product. Through a mathematical analysis.