• Economic and Environmental Geology
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• v.27 no.1
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• pp.93-100
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• 1994

This study examined the mechanisms of lead transport in the groundwater system and those of irregular detections in groundwater in Door County, Wisconsin. During the spring recharge period in 1991, water-level movement and water-quality change were monitored from two monitoring wells equipped with three piezometers each and from five house wells, respectively. Water-level responses to recharge events were fast with a relatively short lag time ranging from 3 to 10 days, indicating that recharge of groundwater occurs through the high hydraulic conductivity (K) zones in the Silurian dolomite aquifer system. Lead was detected only on particles filtered from groundwater, but not in dissolved state. Concentrations ranged from 0.2 to $7.1{\mu}g/mg$, converted into the total lead concentration in groundwater ranging from $0.3{\mu}g/l$ to $4.7{\mu}g/l$. A lag time between recharge events and peak particle movement at the sampled wells was estimated to range from 19 to 22 days. Due to the particulate nature of lead in groundwater, only the wells connected with the high K zones detect lead, causing the spatial variation. In a given well, lead concentration varies at different sampling times due to the variation in the initial amounts of lead-carrying particles introduced into the groundwater system during recharge events, the lag in particle transport and the dispersion of lead-carrying particles along the advective flowpaths.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.687-693
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• 2016

The rapid turning and acceleration movement of a rotorcraft leads to a sloshing phenomenon in the fuel tank. Sloshing caused by rapid movement can affect the internal components by creating an excessive load. In severe situations, the resulting damage to the internal components and pipes can also lead to the tearing of the fuel tank itself. Therefore, to improve the survivability of the crew, the internal components of the fuel tank must be designed to retain their structural soundness during the sloshing phenomenon. In order to accomplish this, the sloshing load acting on the components first needs to be determined. This paper investigates the sloshing load applied to the internal components by performing numerical analysis for rotary-wing aircraft fuel tanks in the sloshing test. Fluid-Structural Interaction (FSI) analysis based on smoothed particle hydrodynamics (SPH) is conducted and the conditions specified in the US military standard (MIL-DTL-27422D) are employed for the numerical simulation. Based on this numerical simulation, by analyzing the load applied to the internal components of the fuel tank due to the sloshing phenomenon, the possibility of obtaining the design data by numerical analysis is examined.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.529-539
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• 1997

The circulations and movement of suspended materials by tidal residual current and seasonal surface wind in the Yellow Sea and the East China Sea are investigated by using a 2-dimensional barotropic model and a particle tracing technique. The tidal residual current is relatively strong around the south and west coast of Korea including the Cheju Island and southern coast of China. The current has a maximum speed of 10 cm/s in the vicinity of Cheju Island with a clockwise circulation. General tendency of the current, however, is to flow eastward along the southern coast of Korea. At the east coast of China from Shanghai to Tunghai, it also shows a eastward flow toward the South Sea of Korea. The anticyclonic circulation formed by wind-driven current and southward current prevails along the coast of Korea in the winter season(from October to April) when northerly wind is dominant. In summer(represented by July), however, the cyclonic circulation appears due to the influence of southerly wind. Suspended materials are advected by tidal residual current and wind-driven current. The long period(ten days) displacement by wind-driven current is bigger than that by tidal residual current. However, the tidal residual current would have the more important role for the advection of the suspended material considering longer period more than several months.

• Journal of Environmental Health Sciences
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• v.44 no.1
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• pp.1-14
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• 2018

Objectives: The purpose of this study is to investigate the main cause of visibility impairment by analyzing the contributions of the light extinction coefficient of major air pollution components and the change of the light extinction coefficient by relative humidity. Methods: The characteristics of the light extinction coefficient calculated by the photochemical method using fine particle component data measured in 2015 in the Gwangju area were examined. Results: The extinction efficiency per unit mass of $PM_{2.5}$ particles was $4.5m^2/g$ and that of $PM_{10-2.5}$ particles was $0.6m^2/g$. This difference indicates that most of the visibility impairment in Gwangju was caused by $PM_{2.5}$ particles. When visibility was poor, the contribution of ammonium sulphate and ammonium nitrate was significantly increased. Relative humidity was also a major cause of visibility decay. The influx of air currents in Gwangju was mostly caused by the long distance movement of pollutants emitted from the eastern part of China. Ammonium sulphate and ammonium nitrate, which are hygroscopic secondary contaminants, were the main causative agents of visibility impairment. Conclusions: Ammonium sulphate and ammonium nitrate were the main causative agents of visibility impairment in Gwangju. The influx of air currents in Gwangju was mostly caused by the long distance movement of pollutants emitted from the eastern part of China.

• Current Research on Agriculture and Life Sciences
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• v.16
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• pp.15-23
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• 1998

This experiment did comparison and analysis that protected soil particle migration have affect on function of the filter and therefore fall function of the filter. Results obtained are as follows: 1.High water head makes to be much movement of fine sand and out flow of particle to the outside. The filter have large opening size that reached stability an early stage, but much fine sand is washed away. If the velocity turns fast and becomes small, blocking phenomenon is remarkable nearby the filter-sand interface. 2. The movement of fine sand that effect on function of filter depend on opening size and change of water head. Under the same condition, USCE filter and USSPL filter is reached earlier than other filter that is stability of stage, because it's opening size is large. 3. Residual quantity of fine sand migration was largly come out in order of USSPL, USCE, USBR, Newton & Hurley, Bertram filter. 4. The time required to stability of flow was taken less in order of Bertram, Newton & Hurley, USBR, USSPL, USCE filter and coefficient of permeability was highly come out in order of USBR, Bertram, Newton & Hurley, USSPL, USCE filter. 5. It proved that USCE and USSPL is suitable for the filter criteria.

• Particle and aerosol research
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• v.14 no.4
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• pp.135-144
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• 2018

Based on a two-year measurement data, major sources for the ambient carbonaceous aerosols at the Anmyeon Global Atmosphere Watch (GAW) station were identified by using the Positive Matrix Factorization (PMF) model. The particulate matter less than or equal to $2.5{\mu}m$ in aerodynamic diameter (PM2.5) aerosols were sampled between June 2015 to May 2017 and carbonaceous species including ~80 organic compounds were analyzed. When the number of factors was 5 or 6, the performance evaluation parameters showed the best results, With 6 factor case, the characteristics of transported factors were clearer. The 6 factors were identified with various analyses including chemical characteristics and air parcel movement analysis. The 6 factors with their relative contributions were (1) anthropogenic Secondary Organic Aerosols (SOA) (10.3%), (2) biogenic sources (24.8%), (3) local biomass burning (26.4%), (4) transported biomass burning (7.3%), (5) combustion related sources (12.0%), and (6) transported sources (19.2%). The air parcel movement analysis result and seasonal variation of the contribution of these factors also supported the identification of these factors. Thus, the Anmyeon Island GAW station has been affected by both regional and local sources for the carbonaceous aerosols.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.155-166
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• 1999

The construction of the coastal structures and reclamation work causes the circulation reduced in the semi-closed inner water area and the unbalanced sediment budget of beach results in an alteration of beach topography. Among the various fluid motions in the nearshore zone water particle motion due to wave and wave-induced currents are the most responsible for sediment movement. Therefore it is needed to predict the effect of the environmental change because of development and so the prediction of wave transformation dose. The purpose of this study is to introduce the relation between waves wave-induced currents and sediment movement. In this study we will show numerical method using energy conservation equation involving reflection diffraction and reflection and the surfzone energy dissipation term due to wave breaking is included in the basic equation. For the wave-induced current the momentum equation was combined with radiation stresses lateral mixing and friction Various information is required in the prediction of wave-induced current depending on the prediction tool. We can predict changes in wave-induced current from the distribution of wave especially near the wave breaking zone. To evaluate these quantities we have to know the local condition of waves mean sea level and so on. The results from the wave field and wave-induced current field deformation models are used as input data of the sediment transport and bottom change model. Numerical model were established by a finite difference method then were applied to the development plan of the eastern Pusan coastal zone Yeonhwa-ri and Daebyun fishing port. We represented the result with 2-D graphics and made comparison between before and after development.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.177-190
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• 2017

This paper presents the results of an experimental study on the effect of large underground station construction method under an existing pile supported bridge using reduced-scale model tests. A series of tests were conducted on design alternatives using 1g models for different design options for which tunnel structures were created considering the similitude law. Deformation fields obtained using the PIV analysis and LVDTs together with strains in tunnel structures were used to investigate the effect of the construction methods on the pile supported bridge. The results of the tests demonstrated that the pipe roof structure is more efficient in limiting the ground deformation as well as the settlement of bridge foundation than a 2-Arch tunnel. It is also shown that the PIV analysis can be effectively used in analyzing ground tunneling induced ground movement for cases in which a construction sequence governs ground movement.

• Smart Structures and Systems
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• v.22 no.5
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• pp.561-574
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• 2018

In this paper, for efficiently reducing the computational cost of the model updating during the optimization process of damage detection, the structural response is evaluated using properly trained surrogate model. Furthermore, in practice uncertainties in the FE model parameters and modelling errors are inevitable. Hence, an efficient approach based on Monte Carlo simulation is proposed to take into account the effect of uncertainties in developing a surrogate model. The probability of damage existence (PDE) is calculated based on the probability density function of the existence of undamaged and damaged states. The current work builds a framework for Probability Based Damage Detection (PBDD) of structures based on the best combination of metaheuristic optimization algorithm and surrogate models. To reach this goal, three popular metamodeling techniques including Cascade Feed Forward Neural Network (CFNN), Least Square Support Vector Machines (LS-SVMs) and Kriging are constructed, trained and tested in order to inspect features and faults of each algorithm. Furthermore, three wellknown optimization algorithms including Ideal Gas Molecular Movement (IGMM), Particle Swarm Optimization (PSO) and Bat Algorithm (BA) are utilized and the comparative results are presented accordingly. Furthermore, efficient schemes are implemented on these algorithms to improve their performance in handling problems with a large number of variables. By considering various indices for measuring the accuracy and computational time of PBDD process, the results indicate that combination of LS-SVM surrogate model by IGMM optimization algorithm have better performance in predicting the of damage compared with other methods.

• Journal of the Korea Society of Computer and Information
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• v.26 no.11
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• pp.51-57
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• 2021

In this paper, we propose a new framework that calculates the user's hand motions using a Leap Motion device, and uses this to practice and analyze arm muscles as well as juggling motions. The proposed method can map the movement of the ball in a virtual environment according to the user's hand motions in real time, and analyze the amount of exercise by visualizing the relaxation and contraction of the muscles. The proposed framework consists of three main parts : 1) It tracks the user's hand position with the Leap Motion device. 2) As with juggling, the action pattern of the user throwing the ball is defined as an event. 3) We propose a parabola-based particle method to map the movement of a juggling shape to a ball based on the user's hand position. As a result, using the our framework, it is possible to play a juggling game in real-time.