• The Journal of Korean Academy of Sensory Integration
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• v.21 no.3
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• pp.39-53
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• 2023

Objective : The purpose was the effect of sensory integration therapy combined with an eye tracker on the sensory processing and visual perception of children with developmental disabilities. Methods : It was a single-subject study with a multiple baseline design between subjects, and the intervention applied sensory integration therapy combined with an eye tracker. Visual-motor speed and saccadic eye movements were assessed at each session of baseline and intervention periods. As pre- and post-evaluation, sensory profile, Korean-Developmental Test of Visual Perception and Trail Making Test were conducted. The results of each session evaluation and pre- and post-evaluation researched the effectiveness of the intervention through visual analysis and trend line analysis. Results : As a result of the evaluation for each session, the slope of the trend line for all children in visual-motor speed and saccadic eye movement increased sharply during the intervention compared to the baseline. As a result of the pre- and post-evaluation, the sensory processing of movement, body position, and visual changed from more than that of peers to a level similar to that of peers. In visual perception, all children's ability of Visual Closure increased. As a result of Trail Making Test conducted to confirm the improvement of children's visual tracking and visual-motor abilities, all children showed a decrease in performance time after the test compared to before. Conclusion : It was confirmed that sensory integration therapy combined with an eye tracker for developmental disabilities has effect on sensory processing and visual perception. It is expected to play an important role clinically as it can stimulate children's interest and motivation in line with recent technological improvements and the spread of smart devices.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.447-457
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• 2008

Laboratory tests for single plane sliding were conducted using the model rock slope to investigate the cut slope deformability and failure mechanism due to combined effect of engineering characteristics such as angle of sliding plane, water force, joint roughness and infillings. Also the possibility of prediction of slope failure through displacement monitoring was explored. The joint roughness was prepared in forms of saw-tooth type having different roughness specifications. The infillings was maintained between upper and lower roughness plane from zero to 1.2 times of the amplitude of the surface projections. Water force was expressed as the percent filling of tension crack from dry (0%) to full (100%), and constantly increased from 0% at the rate of 0.5%/min and 1%/min upto failure. Total of 50 tests were performed at sliding angles of $30^{\circ}$ and $35^{\circ}$ based on different combinations of joint roughness, infilling thickness and water force increment conditions. For smooth sliding plane, it was found that the linear type of deformability exhibited irrespective of the infilling thickness and water force conditions. For sliding planes having roughness, stepping or exponential types of deformability were predominant under condition that the infilling thickness is lower or higher than asperity height, respectively. These arise from the fact that, once the infilling thickness exceeds asperities, strength and deformability of the sliding plane is controlled by the engineering characteristics of the infilling materials. The results obtained in this study clearly show that the water force at failure was found to increase with increasing joint roughness, and to decrease with increasing filling thickness. It seems possible to estimate failure time using the inverse velocity method for sliding plane having exponential type of deformability. However, it is necessary to estimate failure time by trial and error basis to predict failure of the slope accurately.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.619-633
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• 1994

A wave deformation model for general purpose combined refraction, diffraction, and breaking is developed in the shallow water. A parabolic approximation equation considered a higher order diffraction term is derived from the previous mild slope equation. A wave energy dissipation term due to bottom friction and breaking is introduced from the turbulence model. The Crank-Nicoloson implicit scheme is used in the numerical calculation, then the solutions are compared with the various hydraulic experiment data in the circular, the elliptic shoal, and the surf zone. The wave height decay in the surf zone is sensitively affected by the incident wave steepness, and the wave height variation around the elliptic shoal is well explained by the non-linear dispersion relation and the wave energy dissipation term. The model is also applied to a field coastal area and reasonable results are obtained.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.4
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• pp.61-69
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• 2010

The collapse of a slope or cut embankment brings much damage to life and property. Accordingly, it is very important to analyze the spatial distribution by calculating the landslide susceptibility in the estimation of the risk of landslide occurrence. The heuristic, statistic, deterministic, and probabilistic methods have been introduced to make landslide susceptibility maps. In many cases, however, the reliability is low due to insufficient field data, and the qualitative experience and knowledge of experts could not be combined with the quantitative mechanical?analysis model in the existing methods. In this paper, new modeling method for a probabilistic landslide susceptibility analysis combined Bayesian Network with ontology model about experts' knowledge and spatial data was proposed. The ontology model, which was made using the reasoning engine, was automatically converted into the Bayesian Network structure. Through conditional probabilistic reasoning using the created Bayesian Network, landslide susceptibility with uncertainty was analyzed, and the results were described in maps, using GIS. The developed Bayesian Network was then applied to the test-site to verify its effect, and the result corresponded to the landslide traces boundary at 86.5% accuracy. We expect that general users will be able to make a landslide susceptibility analysis over a wide area without experts' help.

• Land and Housing Review
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• v.11 no.1
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• pp.109-116
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• 2020

This study aims to establish an approach to assess urban flood vulnerability by identifying social characteristics such as the road transportation and the vulnerable groups. Assessment procedures comprise three steps as: (1) composing the assessment criteria to reflect the urban characteristics; (2) calculating the weight; and (3) evaluating the vulnerability. The criteria were adopted by Delphi survey technique. Four criteria as land cover, residents, vulnerable areas, and disaster response were adopted in the current study. To determine the weight set of criteria, subjective and objective methods were combined. The weight set was determined using the combined method which reflects the Delphi method and Entropy analysis. In the process of data-based construction, GIS tools wwere used to extract administrative unit materials such as land cover, road status, and slope. Data on population and other social criteria were collected through the National Statistical Office and the Seoul Metropolitan statistical data. TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) technique, which uses materials from cell units in order to rank the closest distance to the best case and the farthest distance from the worst case by calculating the distances to the area of assessment, was applied to assess. The study area was the Dorimcheon basin, a flood special treatment area of Seoul city. The results from the current study indicates that the established urban flood vulnerability assessment approach is able to predict the inherent vulnerable factors in urban regions and to propose the area of priority control.

• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.9-19
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• 2021

This study evaluated the feasibility of combined use of physical separation and soil washing to remediate heavy metals (Pb and Cu) contaminated soil in a military shooting range. The soils were classified into two types based on the level of heavy metal concentrations: a higher contaminated soil (HCS) with Pb and Cu concentrations of 6,243 mg/kg and 407 mg/kg, respectively, and a lower contaminated soil (LCS) with their concentrations of 1,658 mg/kg and 232 mg/kg. Pb level in both soils exceeded the regulatory limit (700 mg/kg), and its concentration generally increased with decreasing soil particle size. However, in some cases, Pb concentrations increased with increasing soil particle size, presumably due to the presence of residues of bullets in the soil matrix. As a pretreatment step, a shaking table was used for physical separation of soil to remove bullet residues while fractionating the contaminated soils into different sizes. The most effective separation and fractionation were achieved at vibration velocity of 296 rpm/min, the table slope of 7.0°, and the separating water flow rate of 23 L/min. The efficiency of ensuing soil washing process for LCS was maximized by using 0.5% HCl with the soil:washing solution mixing ratio of 1:3 for 1 hr treatment. On the contrary, HCS was most effectively remediated by using 1.0% HCl with the same soil:solution mixing ratio for 3 hr. This work demonstrated that the combined use of physical separation and soil washing could be a viable option to remediate soils highly contaminated with heavy metals.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.401-412
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• 2008

Simulations of three-dimensional numerical wave tank are performed to investigate wave force acting on a large cylindrical structure and consequent wave deformation, which are induced by bore after breaking waves. The numerical model is based on the three-dimensional Navier-Stokes equations with a finite-difference method combined with a volume of fluid(VOF) method, which is capable of tracking the complex free surface, including wave breaking. In order to promote wave breaking of the incident wave, the approach slope was built seaward of the structure with a constant slope and a large cylindrical structure was installed on a flat bed. The incident waves were broken on the approach slope or flat bed by its wave height. In the present study, all waves acting on the large cylindrical structure were limited to breaking bore after wave breaking. The effects of the position of the structure and the incident wave height on the wave force and wave transformations were mainly investigated with the concern of wave breaking. Further, the relations between the variation of wave energy by wave propagation after wave breaking and wave force acting on the structure were discussed to give the understanding of the full-linear wave-structure interactions in three-dimensional wave fields.

• Computers and Concrete
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• v.8 no.2
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• pp.177-192
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• 2011

This research paper aims at computer based modeling of carbonation induced corrosion under extreme conditions and its experimental verification by incorporating enhanced electrochemical and mass balance equations based on thermo-hygro physics with strong coupling of mass transport and equilibrium in micro-pore structure of carbonated concrete for which the previous research data is limited. In this paper the carbonation induced electrochemical corrosion model is developed and coupled with carbon dioxide transport computational model by the use of a concrete durability computer based model DuCOM developed by our research group at concrete laboratory in the University of Tokyo and its reliability is checked in the light of experiment results of carbonation induced corrosion mass loss obtained in this research. The comparison of model analysis and experiment results shows a fair agreement. The carbonation induced corrosion model computation reasonably predicts the quantitative behavior of corrosion rate for normal air dry relative humidity conditions. The computational model developed also shows fair qualitative corrosion rate simulation and analysis for various pH levels and coupled environmental actions of chloride and carbonation. Detailed verification of the model for the quantitative carbonation induced corrosion rate computation under varying relative conditions, different pH levels and combined effects of carbonation and chloride attack remain as scope for future research.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.2
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• pp.133-141
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• 2011

In this study, different calibration approaches for reduced sulfur compounds (RSCs) were investigated by using thermal desorption coupled with gas chromatography (GC) and pulsed flame photometric detection (PFPD). To evaluate the effects of calibration procedures, gaseous standards of 4 RSCs ($H_2S$, $CH_3SH$, DMS, and DMDS) prepared at 10 ppm level were analyzed at 7 loading injection volumes (40, 60, 80, 100, 160, 240, and 320 ${\mu}L$). The results were then compared with calibration curves made with the Z (zero offset) and N (non-zero offset) method. The concentrations of unknown samples were then quantified by using R (ratio) method in which the slope values are compared between standards and samples. Secondly, in A (average) method, results obtained from a multi-point analysis of unknown samples were also averaged to extract representative values for each sample. Results of both experiments showed that analytical error of low molecular weight components (such as $H_2S$ and $CH_3SH$) was greatly expanded with the Z method. In conclusion, the combined application of N-A method was the more realistic approach to reduce biases in the quantification of RSCs.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1236-1240
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• 2006

Flooding is an inevitable problem for many cities. The study has depended on a combined approach of physically based modeling and GIS. The stream network is structured by MIKE11 for basis of a network and extended by MIKE21 to make like 2D analysis. This method is called alternative 2D analysis. In this study, one of area in Korea is used to analyze overflow of stream. Flood risk of the area looks like not so big because an elevation of this area is very high and slope is steep, but it is very dangerous area due to the typhoons. The tools to make flood risk map are MIKE11 and MIKE21 include GIS program. And map is expressed 3-D animation with MIKE Animator. As a result of this work, the flood risk map is made. And everyone who is not an expert can check dangerous area for flooding. At present, the method which is viable and easily confirmable must be promote because one of matters of common interest, which is of the general public, is the flood disaster.