• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.51-61
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• 2002

The objective of this study is to develop GLEANS-PADDY model to predict nutrients loading from paddy-field areas. This model is developed by modifying the GLEANS model which is used for uplands, and composed of hydrology and nutrient submodels. The optimal field size for CLEANS-PADDY model application is about up to 50 ha with mild slope, relatively homogeneous Soils and spatially rainfall, and a single crop farming. The CLEAMS model is modified to handle ponded soil surface condition and saturated soil profile in paddy field. In the hydrology submodel of the CLEAMS-PADDY model. the ponded depth routing method is used to handle the ponded water condition of paddy field. To compute potential evapotranspiration the FAO-24 Corrected Blaney-Criddle method is used for paddy field instead of Penman-Monteith method in the CLEAMS model. In the nutrients submodel of the CLEAMS-PADDY model, the soil was assumed saturated and soil profile in the root zone was divided into oxidized and reduced zones.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.6
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• pp.319-325
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• 2018

This study conducted an experimental investigation on oscillatory behavior of the hydraulic jump roller. Based on the similarity of the hydraulic jump and tidal bore, the behavior of the front face of hydraulic jump with increasing downstream water depth was studied focusing on profile and fluctuation. In this study, for statistical approach, the ensemble averaging was applied to obtain relevant front profile and compared with the time averaging. The front profile gets mildly sloped and the fluctuation of the starting point of hydraulic jump decreases as the downstream water depth increases.

• Journal of the Korean association of regional geographers
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• v.16 no.2
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• pp.100-109
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• 2010

The study examines two different sites to analyze the difference of stream channel profile between two different landuse areas on Neponset River, Boston, MA. Landuse represents the current status of land in terms of human, agricultural or forest, industry and environmental activity types. According to the previous research, forest and urban area are significantly distinguished in chemical characteristic, shape and bed load of the stream. On the chosen sites, I look at the cross-section profile, the slope, velocity, and roughness of the channels. With the data collected at the site I determined the value for the channel bed material using Manning's equation, and compared with the result of HEC-RAS model with the cross-section profile data I measured. In the forest area, water surface elevation and bed material obtained through Manning's equation are very close to HEC-RAS model result. However, in the resident area the Manning's 'n' value calculated much higher than assumption which was considered as cobble whose 'n' value is 0.03-0.06. The difference could be caused by unusual steep elevation on the site and the dam present down further. With the steep elevation upside of dam, there is critical-depth condition occurs. The difference of Manning's 'n' value reflects the difference of depth. HEC-RAS model was run to analyze the difference and the result shows that depth is 0.36 much less than 0.688 what I computed when the Manning's n value is 0.03(cobble) instead of the result of the study (0.13292). Beside, dam is a major source of fragmentation and degradation of stream, and it's possibly inferred upstream water levels are increased and stream velocity is decreased. This study is meaningful for introduction of HEC-RAS in geography field to analyze different sites with channel bed material, and it is going to be used more actively to manage river and river side.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.63-69
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• 2015

In this study, a 2D hydrodynamic model equipped with critical dry depth scheme was developed to reproduce the flow over staircase. The channel geometry of hydraulic experiment conducted by Ishigaki et al. was generated in the computational space, and the developed model was validated against flow properties such as discharge, velocity and momentum. In addition, the water surface profile and the velocity distribution evolved in flow over two layers staircases were analyzed. When the initial water depth at the upper floor was 0.3 m, the maximum velocity at lower floor was 4.2 m/s, and the maximum momentum was $1.2m^3/s^2$, and its conversion to force per unit width was 1.2 kN/m. This value was equivalent to the hydrostatic force with 50 cm water depth, and evacuation became difficult, as proposed by Ishigaki et al. For the flow over staircases connecting two layers, the maximum run-up height in flat part connecting two layers was approximately two times higher than the initial water depth in upper floor, and the rapid shock wave with sharp front and long tail was propagated.

• ETRI Journal
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• v.44 no.1
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• pp.38-50
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• 2022

This paper presents a study on the use of encoder-derived features in decoder-side depth estimation. The scheme of multiview video encoding does not require the transmission of depth maps (which carry the geometry of a three-dimensional scene) as only a set of input views and their parameters are compressed and packed into the bitstream, with a set of features that could make it easier to estimate geometry in the decoder. The paper proposes novel recursive block splitting for the feature extraction process and evaluates different scenarios of feature-driven decoder-side depth estimation, performed by assessing their influence on the bitrate of metadata, quality of the reconstructed video, and time of depth estimation. As efficient encoding of multiview sequences became one of the main scopes of the video encoding community, the experimental results are based on the "geometry absent" profile from the incoming MPEG Immersive video standard. The results show that the quality of synthesized views using the proposed recursive block splitting outperforms that of the state-of-the-art approach.

• Economic and Environmental Geology
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• v.30 no.5
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• pp.443-450
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• 1997

The main purpose of this study is to investigate mineralogical and chemical changes during natural weathering, and assess the mobility of major and trace elements. Yongwol power plant utilize anthracite coal which is mainly composed of illite, kaolinite, pyrophyllite and quartz in mineralogy. Coal and coal-derived fly ash samples were sampled by the electrostatic precipitator in Yongwol coal-fired power plant in Korea. Short term weathered fly ash were also collected in ash disposal mound, and two profile soil samples were taken from an ash near the power plant. Amorphous materials are the main component of the fly ash, and mullite, quartz, magnetite and heamatite are present in all coal-derived fly ash. In chemistry, Si and Al are the most abundant elements of the total content. The ash samples were fractionated into upper $90{\mu}m$ and under $45{\mu}m$ size. Finer particles show higher concentrations in metal contents including Co, Cr, Cu, Ni, V, Zn and Pb. Concentration of Zn and Pb are nearly 4 times higher concentration in the finer particles. For the profile samples, the concentrations of $SiO_2$, $Na_2O$, MgO and $K_2O$ generally show increasing trends with depth, whereas those of $Fe_2O_3$ and $TiO_2$ appear to decrease with depth. Content of MnO does not show any specific depth trend. For the trace elements, Co, Cu, Ni and V show increasing concentrations with depth.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.201-206
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• 2020

A stress-induced brittle failure in deep tunneling generates spalling and slabbing, eventually causing a v-shaped notch formation. An empirical relationship for the depth of the notch to the maximum tangential stress assuming an equivalent circular cross-section was proposed (Martin et al. 1999). While this empirical approach has been well recognized in the industry and used as a design guideline in many projects, its applicability to a non-circular opening is worth revisiting due to the use of equivalent circular profile. Moreover, even though the extent of the notch also contributes to notch failure, it has not been estimated to date. When the estimate of both the depth and the extent of notch are combined, a practical and economically justifiable support design can be achieved. In this study, a new methodology to assess the depth as well as the extent of notch failure is developed. Field data and numerical simulations using the Cohesion Weakening Frictional Strengthening (CWFS) model were collected and correlated with the three most commonly accepted failure criteria (σ₁/σ₃, D_is=σ_max/σ_c, σ_dev/σ_cm). For the numerical analyses, the D-shaped tunnel was used since most civil tunnels are built to this profile. Inferential statistical analysis is applied to predict the failure range with a 95% confidence level. Considering its accuracy and simplicity, the new correlation can be used as an enhanced version of failure assessment.

• Journal of Korean Dental Science
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• v.13 no.1
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• pp.11-20
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• 2020

Purpose: This study sought to identify differences in hard and soft tissue chin profile changes in skeletal Class III patients after bimaxillary surgery, with or without advancement genioplasty. Materials and Methods: The retrospective study was conducted based on cephalometric analysis of skeletal and soft tissue variables. Lateral cephalograms taken at 3 different time points were utilized: pre-operation (T0), immediately post-operation (T1), and at least 6 months (11.0±2.6 months) post-operation (T2). The 2 groups were matched for sample size (n=20 each). Data were analyzed using independent t-tests with Bonferroni correction. Result: Group N (bimaxillary surgery alone) and Group G (bimaxillary surgery with an advancement genioplasty by horizontal sliding osteotomy) did not differ significantly in terms of demographic characteristics. The soft tissue chin thickness of Group G increased more after surgery, followed by a greater decrease during the postoperative period, and was eventually not significantly different from Group N at T2. On the other hand, the mentolabial sulcus depth of Group G (5.5±1.3 mm) was significantly greater than that of Group N (4.4±0.9 mm) (P=0.006) at T2. Conclusion: Although Group G showed a statistically significantly greater decrease in soft tissue chin thickness during the postoperative period, there were no significant intergroup differences in the chin profile for at least 6 months after the surgery, except for the mentolabial sulcus depth, which was greater in Group G than in Group N.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.452-457
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• 2000

The object of this study is to develop a reliable FEM simulation technique for the analysis of can making process using PAM-STAMP software. The processes consist of doming and necking in addition to drawing, redrawing. After body making process, this study analyzed the stability for internal pressure by simulating buckling test. Through these technique, we estimated the dome reversal pressure of steel D&I Can for various can profile and process conditions. From this study, we found the cause and mechanism of wrinkling during necking process. This mechanism is largely affected by can wall thickness and the clearance between knock out punch and necking die. The dome reversal pressure improves with increasing dome depth. These results validate the usefulness of the developed simulation technique for the analysis of body making process and optimization of the dome profile.

• Transactions of Materials Processing
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• v.24 no.3
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• pp.212-217
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• 2015

SmartCrown is a system to control the plate crown by shifting the sine-shaped work rolls in the axial direction. The control range of the plate crown depends on a depth of sine-shaped roll profile because the roll radius varies continuously along the axial direction. When the roll profile is changed to improve the control range, the contact stress between the work roll and the back-up roll also changes. In the current study, the contact stress for various profiles and rolling conditions were analyzed using the finite element method and compared with results from Hertzian contact theory. A submodel method is used to increase the accuracy of the finite element analysis. The analysis results showed that the maximum increase in the contact stress was only 53MPa, so it is anticipated that no back-up roll spalling will occur.