• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.15-29
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• 1999

This study presents an analytical method of estimating the developed horizontal active thrusts against GRS-RW( Geosynthetic Reinforced Soil Retaining Wall) system adapted to the case of distanced surcharge. In addition, the design charts that could be used for preliminary design of GRS-RW system are presented. The proposed method of analysis uses two body translation mechanism as well as force polygon concept. taking into account the effect of facing's rigidity. Besides. the effect of tension cracks in c-\Phi$ soils, seismic effects and horizontal distance from the back face of wall to uniformly distributed surcharge loadings are also included. The results of horizontal active thrusts obtained from the developed method of analysis are compared with those from Jarquio's modified Boussinesq equation.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.617-622
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• 2013

The sloshing of liquid inside an ocean floater is caused by disturbances due to waves. For the analysis of sloshing impact within the floater and that of waves on the floater, the coupled analysis method is used. The Stokes $5^{th}$ order non-linear wave theory equations were adapted for wave making. Furthermore, Navier-Stokes equation and Shear-Stress Transport (SST) turbulent model were used to Computational Fluid dynamics, where the ocean floater motions are considered the heave and the pitch motion. The results obtained confirms the mutual relationship between the rigid body motions and that of sloshing, where the sloshing behaviour within the floater is characterized by the wave effects on the floater.

• The Journal of the Acoustical Society of Korea
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• v.21 no.1
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• pp.73-81
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• 2002

The transmission of vibration energy through beam-plate junctions in vibration intensity analysis called power new analysis (PFA) has been studied. PFA is an analytic tool for the prediction of frequency averaged vibration response of built-up structures at medium to high frequency ranges. The power transmission and reflection coefficients between the semi-infinite beam and plate are estimated using the wave transmission approach. For the application of the power coefficients to practical complex structures, the numerical methods, such as finite element method are needed to be adapted to the power flow governing equation. To solve the discontinuity of energy density at the joint, joint matrix is developed using energy flow coupling relationships at the beam-plate joint. Using the joint matrix developed in this paper, an idealized ship stem part is modeled with finite element program, and vibration energy density and intensity are calculated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.16-22
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• 2004

Unsteady vortex shedding behind a rectangular cylinder near a wall influences both increasing of drag and dynamic stability of heavy vehicle, bridge or building. Incompressible Averaged Navier-Stokes equation with modified ${\varepsilon}-SST$ turbulence model is adapted for investigating the flow field between the rectangular cylinder and the wall. In case the vortex shedding happens, not only the averaged maximum velocity is higher than other cases, but the position of the maximum velocity is closer to the lower surface of rectangular cylinder. On this study, it is confirmed that the vortex shedding behind a rectangular cylinder can be suppressed by the passive control method added by horizontal and vertical fences to the lower surface of rectangular cylinder.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.101-108
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• 2018

This study was carried out to obtain baseline data on the causes of industrial accidents and their prevention by investigating structural models between the Shipyard workers' egogram ego-states (CP: Critical Parent, NP: Nurturing Parent, A: Adult, FC: Free Child, AC: Adapted Child), safe and unsafe behaviors, and industrial accidents (frequency/severity). In order to achieve this goal, 378 workers from 3 locations of major corporations in Geojedo Island and Ulsan took a questionnaire, which was then analyzed with a structural equation model using the SPSS 23.0 and AMOS 24 statistics package, and the main results of the study are as follows. First, NP and A's ego-states had a positive influence on safe behavior, AC's ego-state had a negative influence on safe behavior, and A's ego-state had the largest influence on safe behavior. Second, CP and AC's ego-states had a positive influence on unsafe behavior, and A's ego-state had a negative influence on unsafe behavior. AC's ego-state had the largest influence on unsafe behavior. Third, safe behavior did not have a significant influence on industrial accidents. However, unsafe behavior had a positive influence on industrial accident frequency and industrial accident severity, both sub-factors of industrial accidents. This study, despite its limitations, such as sampling limitations, has the following significance. First, this study verified that ego-state, a psychological characteristic, is an important factor for predicting unsafe behavior that induces industrial accidents. Second, in order to reduce industrial accidents, there is a need to stimulate the A ego-states, and promote continuous safety management and safety education to neutralize the AC ego-state. Third, previous studies were limited in the area of practical methods for reducing unsafe behaviors, but this study presents practical methods for reducing unsafe behaviors by verifying the structural relationship between safe/unsafe behaviors and industrial accidents by selecting ego-gram ego-states, variable personality theory, as an independent variable.

• Geophysics and Geophysical Exploration
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• v.12 no.2
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• pp.183-191
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• 2009

Finite difference method using not general SSG (standard staggered grid) but RSG (rotated staggered grid) was applied to simulation of elastic wave propagation. Special free surface boundary condition such as imaging method is needed in finite difference method using SSG in elastic wave propagation. But free surface boundary condition in finite difference method using RSG is easily solved with adding air layer or vacuum layer. Recently PML (Perfectly Matched layer) is widely used to eliminate artificial reflection waves from finite boundary because of its' greate efficiency. Absorbing ability of CPML (convolutional Perfectly Matched Layer) that is more efficient than that of PML and CPML that don't use splitting of wave equation that should be adapted to PML was applied to FDM using RSG in this study. Frequency absorbing characteristic and energy absorbing ability in CPML layer were investigated and CPML eliminated artificial boundary waves very effectively in FDM using RSG in being compared with that of Cerjan's absorbing method. CPML method also diminished amplitude of waves in boundary layer of solid-liquid model very well.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.185-190
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• 2016

Breast cancer is the first or second malignancy among women worldwide. Illness perception (IP) and quality of life (QoL) are major issues considering breast cancer management. An attempt was here made to inspect the predictive variables influencing IP and their impact on QoL in cancer patients. The key predictors adapted from previous studies including life satisfaction, perceived social support, self-esteem, hope, optimism, and spiritual well being were taken into account. Our sample included 200 female volunteers suffering from breast cancer applying exclusion criteria. The data were collected using various questionnaires and statistically analyzed by means of path analysis and structural equation modeling. The results revealed that of the six predictors, spiritual well being and social support had direct effects on QoL and IP. The only path with significant indirect correlation with IP was social support. Spiritual well being had the second significant direct effect on IP. Self-esteem occupied the third rank in direct effects on both QoL and IP. In conclusion, here in Iran and most likely in other strongly religious communities, spiritual intervention is an effective strategy to raise QoL. Also social support helps women suffering from breast cancer to experience better conception and coping strategies.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.12
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• pp.4013-4026
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• 1996

A numerical simulation has been carried out for the jet impinging on a flat plate and a semi-circular concave surface. In this computation finite volume method was employed to solve the full Navier-Stokes equation based on a non-orthogonal coordinate with non staggered variable arrangement. The standard k-.epsilon. turbulent model and low Reynolds number k-.epsilon. model(Launder-Sharmar model) with Yap's correction were adapted. The accuracy of the numerical calculations were compared with various experimental data reported in the literature and showed good predictions of centerline velocity decay, wall pressure distribution and skin friction. For the jet impingement on a semi-circular concave surface, potential core length was calculated for two different nozzle(round edged nozzle and rectangular edged nozzle) to consider effects of the nozzle shape. The result showed that round edged nozzle had longer potential core length than rectangular edged nozzle for the same condition. Heat transfer rate along the concave surface with constant heat flux was calculated for various nozzle exit to surface distance(H/B) in the condition of same jet velocity. The maximum local Nusselt number at the stagnation point occurred at H/B = 8 where the centerline turbulent intensity had maximum value. The predicted Nusselt number showed good agreement with the experimental data at the stagnation point. However heat transfer predictions along the downstream were underestimated. This results suggest that the improved turbulence modeling is required.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.499-508
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• 2016

We investigated regional differences in the growth and maturation rate of Pacific cod in the East and Yellow Seas. Significant regional differences were detected in the von Bertalanffy growth equation and mean length at maturity (L₅₀). Cod in the East Sea grew at a faster rate than those in the Yellow Sea, with females growing faster than males in both populations. Cod of both sexes matured earlier in the Yellow Sea (age of maturity: 2.3 years for males, 2.6 years for females) than in the East Sea (age of maturity: 3.9 years for males, 4 years for females). These regional differences suggest that Pacific cod in the Yellow Sea, which is at the southwestern extremity of global cod distribution and thus likely to be an inhospitable habitat for this species, have adapted to their environment by developing earlier maturation and slower growth than cod in the East Sea or the Korea Strait. These regional differences must be taken into account when setting biological reference points for management of the Pacific cod fishery in Korean waters.

• Journal of Korean Society on Water Environment
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• v.33 no.6
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• pp.626-639
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• 2017

Based on an ecological monitoring in a Korean stream (Gapyeong), Habitat Suitability Index (HSI) of nine fish species was developed for three physical habitat factors : current velocity, water depth and substrate. The species were chosen based on their abundance and frequency in the fish community of the Gapyeong stream. The Weibull model was used as the probability density function to analyze the distribution and number of each fish species according to the three identified physical factors, which showed good results. This HSI equation has advantages because it statistically expresses habitat preferences of fish species simply and clearly. From that, we can quantitatively deduce the central tendency and variation of environmental factors for fish distribution. The selected fish species showed different preferences for each habitat factor respectively. Although there are some exceptions, the distribution and abundance of individual species of nektonic fish (Zacco koreanus, Zacco platypus, Microphysogobio longidorsalis and Pungtungia herzi) were positively skewed to deep water and fine substrate while riffle-benthic fish (Koreocobitis rotundicaudata and Coreoleuciscus splendidus) were normally distributed at the shallow and coarse substrate zone. It seems that the species showing the positively skewed distribution to the current, Z. koreanus, Z. platypus, M. longidorsalis and P. herzi have adapted themselves to the fast current and have expanded their niche.