• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.195-201
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• 2006

The wave load and its influence on the response of offshore structure have been well investigated through the statistical approach based on the linear theory. The linear approach has a limitation to apply the extreme condition such as freak wave, which corresponds to extreme value of wave spectrum. The main topic of present study is to develop an efficient numerical method to predict wave load induced by extreme wave. As a numerical method, finite element method based on variational principle is adopted. The frequency-focusing method is applied to generate the extreme wave in the numerical wave tank. The wave load on the bottom mounted vertical cylinder is investigated. The hydroelastic response of the vertical cylinder is also investigated so as to compare the wave loads with the rigid body case in the extreme wave condition.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.127-142
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• 2000

This study have been carried out to find out the mechnical effect of Multiloop Edgewise Arch Wire(MEAW) making use of the finite element method. The tip back bend of MEAW taken in this analysis is $5^{\circ},\;10{\circ}\;and\;15{\circ}$. In addition, Class II or up & down elastic is applied to find out stress distribution and their values in PDL. A adult male of normal occlusion was selected to create the models of teeth and PDL. And the model of MEAW was also created using commercial finite element code (ANSYS version 5.2). The MEAW is forcibly engaged with a class II or up & down elastic, to determine the initial stress generated in PDL. Comparing the compressive and tensile stress at each reference-planes, following results are obtained. 1. When a MEAW of $5^{\circ},\;10{\circ}\;15{\circ}$ tip back bend was engaged with Class II or up & down elastic, the distribution of compressive, tensile stress in entire PDL is similar in each case. 2. The values of compressive and tensile stress in PDL is higher in $15{\circ}$ tip back bend case than in $10{\circ}\;or\;15{\circ}$ tip back bend case. 3. In the distal PDL of 1st and 2nd molar, compressive stress appears. The compressive area is more wide and its values is higher in PDL of 2nd molar than those in 1st molar. The compressive area and its values become more wide and higher according to the increase of the tip back bend. 4. The values of compressive stress are comparatively smaIIer in PDL of molars than those in premolars. 5. Comparing class II and up & down elastic case, tensile stress values in anterior teeth PDL are smaller md their distribution is more wide in up & down elastic case than class If elastic case. On another hand, there is no difference in distribution and stress values in PDL of posterior teeth between two cases. 6. Comparing the tensile area in PDL of anterior teeth, tensile stress values are maximum in PDL of canine.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.601-608
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• 2012

Platform carriers that were welcomed due to their open policy are now having Vertical-Systematization. As the Vertical-Systematization to strengthen platform's quality intensifies, the qualities of OS, network and manufacturing abilities may be weakened. As the environment changes, consumers move from attractive platform to attractive contents and the killer contents will become the key success factor. Hence, the platform carriers will aim to acquire killer contents to attract more users causing excessive competition for Killer Contents Sourcing. The following paper examines the problems that will stem from fierce competition among platforms, problems regarding the Contents Sourcing and solution for the content-providers.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.141-148
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• 2003

In the recently, the necessity of the hybrid type linear stepping motor(HLSM) of linear motion digital actuator has been increased in the various fields of the automatic control system. The HLSM is directly performed without any converting mechanism. Therefore, the HLSM is better advantaged in the efficiency and economical view than a rotary stepping motor. In this paper, we have designed an optimum tooth shape by the 2D finite element method(FEM) to develop the HLSM with longitudinal flux machine(LFM) type, and calculated the thrust force and normal force. And we have manufactured the prototype of it, and have experimented the thrust force characteristics of it.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.421-425
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• 2003

In this study the occlusion of dural-sac. the outer membrane of spinal cord in the lumbar region. was quantitatively analyzed using one motion segment finite element model. Occlusion was quantified by calculating cross sectional area change of dural-sac for different compressive impact duration (loading rate) due to bony fragment at the posterior wall of the cortical shell in vertebral body. Dural-sac was occluded most highly in the range of 8∼12 msec impact duration by the bony fragment intruding into the spinal canal. $\Delta$t = 400 msec case 4 % cross sectional area change was calculated. which is the same as the cross sectional area change under 6 kN of static compressive loading.

• Journal of Korean Society of Steel Construction
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• v.13 no.2
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• pp.163-176
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• 2001

In this paper, the stress resultants and displacements of simply supported curved girder based on the flexural torsional theory considering torsional warping effects are analyzed. And elastic equations of continuous curved girder are obtained by using energy method. Also, bending moment warping torsional moment diagram, pure torsional moment diagram, shearing force diagram, and deflection diagram of continuos curved girder bridge subjecting to vertical loads and uniform loads are presented.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.203-211
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• 2006

This study was initiated to investigate the difference of playing ability among soccer fields established with natural turfgrass, artificial turf and bare ground. The soccer fields with natural turfgrasses were established with cool-season grass(Kentucky bluegrass 80%+Perennial ryegrass 20%) and zoysiagrass. The artificial turf field was constructed with Konigreen $DV5000^{TM}$. Bare ground was sandy soil. Data such as ball rolling distance and vertical ball rebound were collected at the Sports Science Town of Konkuk University from 2005 to 2006. A ball in the study was Hummel Air Vision #1, certified by KFA(Korea Football Association) in ball pressure of 1.01b. Ball rolling distance was the longest on bare ground(13.6m), followed by artificial grass(11.4m), cool-season grass(7.8m) and zoysiagrass(4.7m). It decreased with lower frequency in use, stronger rigidity and higher density of turfgrass. Vertical ball rebound was the highest on bare ground(1.0m), followed by artificial grass(0.9m), cool-season grass(0.6m) and zoysiagrass(0.4m). It was lower under conditions of low use frequency, strong rigidity, and high density. Both ball rolling distance and vertical ball rebound were not greatly affected by cool-season grass maintained with high intensity of culture by years after establishment. However, zoysiagrass field under low intensity of culture showed longer in ball rolling distance and higher in vertical ball rebound with time after establishment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.223-228
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• 1987

An efficient method for the calculation of wave forces on a tension leg platform(TLP) is presented in this paper. It is based on the Morison's equation with two corrective terms. One is the reduction of the inertia forces on the vertical columns in order to include the wave diffraction effect particularly for small wave conditions. The other is the inclusion of the hydrodynamic forces acting at the bottoms of the columns. Numerical studies are carried out for a TLP in 1000 ft water with two different wave heading angles($0^{\circ}$ and $45^{\circ}$). The reponse amplitude operators(RAO's) for the TLP motions and top tether tension variations are obtained by the present method and the theoretically more accurate method based on the diffraction theory. A comparison has been made between the results obtained by two methods.

• Journal of the Korean GEO-environmental Society
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• v.2 no.2
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• pp.13-22
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• 2001

In this study, centrifuge model tests were fulfilled to investigate the characteristics of bearing capacity of paper ash as a filling material. The model tests were done varying the footing width and gravity level. The settlement and vertical soil pressure by loading were measured. The results from the tests were compared with the one from FLAC program using finite difference method and bearing capacity theory. After all, it was shown that the characteristics of load-settlement represented the local shear failure, which the settlement ratio s/B showed inflection point around 25~30%. As g-level and footing width were increasing, the load strength was increasing. The ultimate bearing capacity from the tests was very closed the results from Terzaghi's theory. As the distance from footing center was increasing, the vertical soil pressure was decreasing. If E/B is higher than 7, the stress by loading was almost increasing. The vertical displacement from loading was the largest one around under the footing and was almost occurred when the depth>4cm and E/B is higher than 5.0.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.385-393
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• 2009

Statement of problem: High stress concentration on the crestal cortical bone has been regraded as a major etiologic factor jeopardizing long term stability of endosseous implants. Purpose: To investigate if the design characteristics of crestal module, i.e. internal type, external type, and submerged type, affect stress distribution on the crestal cortical bone. Material and methods: A cylindrical shaped implant, 4.3 mm in diameter and 10 mm in length, with 3 different crestal modules, i.e. internal type, external type, and submerged type, were analysed. An axisymmetric scheme was used for finite elment formulation. A vertical load of 50 N and an oblique load of 50N acting at $45^{\circ}$ with the implant's long axis was applied. The peak crestal bone stress acting at the intersection of implant and crestal bone was compared. Results: Under vertical load, the crestal bone stress was high in the order of internal, external, and submerged types. Under the oblique loading condition, it was in the order of internal, submerged, and external types. Conclusion: Crestal module design was found to affect the level of the crestal bone stresses although the actual amount was not significant.