• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.7-12
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• 1984

This study was undertaker to observe the longitudinal change by orthodontic treatment for early Class III malocclusion in primary and mixed dentition. Cephalometric roentgenograms of 8 children with Class III malocclusion obtained during activator therapy were measured and compared with those obtained before activator therapy. The following results were observed. During treatment with activator; 1. The maxilla became retrueded in A,C,E, and K and protruded in F, G, H, and J. 2. The mandible became retruded in A,C,E, and F and F and protruded in H and J. No difference was observed in G and K. 3. Gonial angle became reduced in A,C,E,F, and K and increased in H. No difference was observed in G and J. 4. The steepness of mandibular plane became reduced in C,E,F,G,H, and J and increased in A. No difference was observed in K. 5. The inclination of upper incisor became more labially in A,C,E,G,H,J, and K. No difference was observed in F. 6. The inclination of lower incisor became more lingually in all cases.

• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.3
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• pp.115-132
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• 1996

The purpose of this study is to estimate the soil loss amount with Geographic Information System according to the land use change of Buju mountain area in Mokpo city. To estimate the soil loss, Universal Soil Loss Equation which is the most proper technique to predict soil loss in this site condition is adopted and IDRISI, a raster GIS software, is used. GIS application with USLE is very efficient to estimate soil loss accurately and fastly. In order to decide value and to find application method of USLE factors, we used existing rainfall erosion index, soil erodibility analysis, slope length, slope steepness, vegetation management and practices, which are rated by GIS through the analysis of various studies related USLE. The result of this study was compared with the previous other researches to verify our method of constructing numerical data of USLE's factors. The result of verification of our way showed significance for the soil loss in forest area. But the result of verification for the soil loss in forest area. But the result of verification for the soil loss of cultivated area showed some errors. It seems that this result was due to local variation of topographical map.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.3
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• pp.163-169
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• 1991

Sixty seven regular wave tests were performed in a wave-current flume to investigate proper-ties of waves breaking on irregular slope profiles. In these tests, 1/10, 1/20 beach slopes were made using angles and plywoods. A little differences were found in such properties as breaker depth and height indices. runup for plane slopes comparing with other laboratory experiments. however. for smaller deepwater wave steepness, measured breaker height and depth data values were smaller than other formulas. On wave runup agreement was good between experiments and Hunt formula. however. measured data values were influenced by number of breaking. Significant differences were found in breaker depth index for plane and barred slopes. Wave height decay after breaking was found to be smaller than Dally et al.'s formula (1984).

• The Journal of Korean Academy of Prosthodontics
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• v.23 no.1
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• pp.125-136
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• 1985

Occlusal splints have been widely used in dentistry for treatment and diagnosis of signs and symptoms related to dental occlusion. The autor studyed the effect of occlusal splint on masticatory movement of young adult men (mean age 23.8 yrs.). Who had worn. occlusal splint for 1 week. The result were as follows: 1. Lateral movement of the mandible during mastication could be increased after wearing occlusal splint for 1 week. 2. Vertical movement of the mandible during mastication was increased after wearing occlusal splint for 1 week. 3. Maximum opening velocity of the mandible during mastication was increased after wearing occlusal splint for 1 week. 4. Mandibular movement during mastication was more affected by chewing of hard foods than of soft foods following occlusal changes. 5. Steepness of the anterior guidance affected several aspects of masticatory movement. 6. Masticatory movement of the mandible became more regular after wearing occlusal splint for 1 week.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.2
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• pp.277-286
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• 2013

Cross-shore sediment transport is very important factor in the design of coastal structures, and the beach profile is mainly affected by a number of parameters, such as wave height and period, beach slope, and the material properties of the bed. In this study cross-shore sediment movement was investigated using a physical model and various offshore bar geometric parameters were determined by the resultant erosion profile. The experiments on cross- shore sediment transport carried out in a laboratory wave channel for initial base slopes of 1/8, 1/10 and 1/15. Using the regular waves with different deep-water wave steepness generated by a pedal-type wave generator, the geometrical of sediment transport rate and considerable characteristics of beach profiles under storm conditions and bar parameters affecting on-off shore sediment transport are investigated for the beach materials with the medium diameter of $d_{50}$=0.25, 0.32, 0.45, 0.62 and 0.80 mm. Non-dimensional equations were obtained by using linear and non-linear regression methods through the experimental data and were compared with previously developed equations in the literature. The results have shown that the experimental data fitted well to the proposed equations with respect to the previously developed equations.

• Journal of Ocean Engineering and Technology
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• v.21 no.1 s.74
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• pp.18-24
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• 2007

When the wind blows strong, most waves are breaking at sea. Breaking waves occur by exceeding the limitation of wave steepness (wave height/wave length = 1/7). Because a wave of single angular frequency couldn't generate the breaking phenomena at a two-dimensional ocean engineering basin, the breaking wave can be generated by the superposition of waves with various angular frequencies based on dispersion relation. This study investigates the particle kinematics in the breaking wave and the magnitude of the breaking wave exciting force at the breaking point and breaking region. We compare the regular wave load in a regular wave, which has same specifications (wave height, period and length), with the breaking waveload. Also, the experimental results of wave exciting force and particle velocity are investigated, by comparison with the analytic results using the potential theory.

• Wind and Structures
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• v.21 no.3
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• pp.289-309
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• 2015

Vertical profiles of mean and fluctuating wind velocities over water waves were studied, by performing Large-Eddy Simulations (LES) on a fully developed turbulent boundary layer over simplified water waves. The water waves were simplified to two-dimensional, periodic and non-evolving. Different wave steepness defined by $a/{\lambda}$ (a : wave amplitude; ${\lambda}$ : wavelength) and wave age defined by $c/U_b$ (c: phase velocity of the wave; $U_b$ : bulk velocity of the air) were considered, in order to elaborate the characteristics of mean and fluctuating wind profiles. Results shows that, compared to a static wave, a moving wave plays a lesser aerodynamic role as roughness as it moves downstream slower or a little faster than air, and plays more aerodynamic roles when it moves downstream much faster than air or moves in the opposite direction to air. The changes of gradient height, power law index, roughness length and friction velocity with wave age and wave amplitude are presented, which shed light on the wind characteristics over real sea surfaces for wind engineering applications.

• Ocean Systems Engineering
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• v.5 no.2
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• pp.109-123
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• 2015

In the present study, the coupled dynamic response of a Submerged Floating Tunnel (SFT) and mooring lines under regular waves is solved by using two independent numerical simulation methods, OrcaFlex and CHARM3D, in time domain. Variations of Buoyancy to Weight Ratio (BWR), wave steepness/period, and water/submergence depth are considered as design and environmental parameters in the study. Two different mooring-line configurations, vertical and inclined, are studied to find an optimum design in terms of limiting tunnel motions and minimizing mooring-line tension. The numerical results are successfully validated by direct comparison against published experimental data. The results show that tunnel motions and tether tensions grow with wave height and period and decrease with submergence depth. The inclined mooring system is more effective in restricting tunnel motions compared to the vertical mooring system. Overall, the present study demonstrates the feasibility of this type of structure as an alternative to traditional bridges or under-seabed tunnels.

• Ocean Systems Engineering
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• v.10 no.1
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• pp.1-23
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• 2020

Hydrodynamic Drag of Surface combatants pose significant challenges with regard to fuel efficiency and exhaust emissions. Stern flaps have been used widely as an energy saving device, particularly by the US Navy (Hemanth et al. 2018a, Hemanth Kumar and Vijayakumar 2018b). In the present investigation the effect of flap turning angle on drag reduction is numerically and experimentally studied for a high-speed displacement surface combatant fitted with a stern flap in the Froude number range of 0.17-0.48. Parametric investigations are undertaken for constant chord length & span and varying turning angles of 5° 10° & 15°. Experimental resistance values in towing tank tests were validated with CFD. Investigations revealed that pressure increased as the flow velocity decreased with an increase in flap turning angle which was due to the centrifugal action of the flow caused by the induced concave curvature under the flap. There was no significant change in stern wave height but there was a gradual increase in the stern wave steepness with flap angle. Effective length of the vessel increased by lengthening of transom hollow. In low Froude number regime, flow was not influenced by flap curvature effects and pressure recovery was marginal. In the intermediate and high Froude number regimes pressure recovery increased with the flap turning angle and flow velocity.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.1
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• pp.41-49
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• 1997

Computational results from Navier-Stokes equations are presented for the Stokes-wave/flat-plate boundary-layer and wake for small wave steepness(Ak=0.01), including exact and approximate treatments of the viscous free-surface boundary conditions. The macro-scale flow indicate that the variations of the external-flow pressure gradients cause acceleration or deceleration of the streamwise velocity component and alternating direction of the cross flow. Remarkably, the wake displays a greater response, i.e., a bias with regard to favorable as compared to adverse pressure gradients. The micro-scale flow indicates that the free-surface boundary conditions have a profound influence over the boundary layer and near/intermediate wake. Order-of-magnitude estimates are conformed to the computational results. And appreciable errors are introduced through approximations to the free-surface boundary conditions.