• Journal of Korean Association for Spatial Structures
• /
• v.18 no.1
• /
• pp.93-100
• /
• 2018

The retractable roof structures have actions of various types of loads and external forces depending on the retraction and operation conditions of the roof in terms of efficiency of control and maintenance as the aspect of structural plan. In particular, there is a need for studies on the establishment of retraction controlled wind velocity to maintain the stable control and usability of roof structure against strong winds or sudden gusts during the retraction of the roof. In this paper, it was intended to provide basic materials for the development of guidelines on the operation and maintenance of domestic retractable buildings with large space by analyzing the factors affecting the retraction controlled wind velocity for the overseas stadiums with the large spatial retractable roof structures where the sliding system was applied on the steel retractable systems. As a result, the controlled wind velocity tends to decrease as the retractable roof area increases. On the other hand, the controlled wind velocity tends to increase as the retraction time increases. In addition, in the space-grid roof structures, the spherical roof structures type showed the average controlled wind velocity of 10m/sec lower than that of 17.3m/sec for curved-roof structure type, and in the curved-roof structure type, the truss roof structure showed the average controlled wind velocity of 8.9m/sec which is lower than that of 17.3m/sec for the space for the space-grid roof structure.

• Journal of Ocean Engineering and Technology
• /
• v.33 no.1
• /
• pp.68-75
• /
• 2019

A low-crested structure (LCS) is an excellent feature not only because it provides shore protection but also because it is fully submerged. However, in order to properly control waves, it is necessary to maintain a certain range of crest height and width in consideration of the wave dimensions at the installation area. According to previous studies, an LCS has some wave breaking effect when the crest width is more than a fourth of the incident wavelength and the crest depth is less than a third of the incident wave height. In other words, if the crest width of the LCS is small or the crest depth is large, it cannot control the wave. Therefore, when an LCS is installed in a large sea area with a great tidal range in consideration of the landscape, waves cannot be blocked at high tide. In this study, the hydraulic performances of a typical trapezoidal LCS with a constant crest height and a low-crested structure with an adjustable crest height, which was called a tide-adapting low-crested structure (TA-LCS) in this study, were compared and evaluated under various wave conditions through hydraulic experiments. It was found that the wave transmission coefficients of the TA-LCS at high tide were lower than the values for the typical LCS based on empirical formulas. In addition, the hydraulic performances of the TA-LCS for wave reflection control were 12.9?30.4% lower than that of the typical LCS. Therefore, the TA-LCS is expected to be highly effective in controlling the energy of incoming waves during high tide even in a macro-tidal area.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.11a
• /
• pp.309-314
• /
• 1996

Feasibility study has been accomplished to evaluate the effectiveness of the in-vessel core debris cooling through lower cavity flooding using two dimensional finite difference scheme. The volume of cerium pool and decay power rate generated in corium pool were evaluated as important parameters to the temperature distribution on the reactor vessel lower head through previous works. In this study, the corium volume based on the System 80＋ core structure and time dependent decay power rate are considered for feasibility evaluation. In addition, preliminary plans for the in-vessel core debris cooling through lower cavity flooding as severe accident management strategy, i.e. flooding timing, method and capacity, are suggested based on the result of the numerical study, international tendency related to in-vessel core debris cooling through lower cavity flooding.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.7 no.1
• /
• pp.17-21
• /
• 2008

Recently developed automotive components are of lightweight nature, providing automobiles with a high fuel efficiency and performance. In response to those trends of car developments, this study proposes a structural optimization method for the lower control ann. Lightweight design of lower control am can be achieved through two approaches: design and material technology. In this research, the former includes optimization technology, and the latter the technologies for selecting aluminum as a steel-substitute material. In this research, the design of experiments(DOE) built in ANSYS WORKBENCH are utilized to determine the optimum shape of a Lower Control Arm. And optimum design is compared first model and reduced design variable model that considered sensitivity using orthogonal array.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.6
• /
• pp.29-34
• /
• 2017

This study analyzed automobile lower arm assembly structure and fatigue to identify configuration changes to enhance structural safety. Parts connected to the car body were fixed and 500 N load was applied at the lower arm head. Maximum equivalent stress and maximum total deformation were minimized for model 1 ( MPa and 0.10315 mm, respectively). Fatigue analysis using extreme SAE bracket history fatigue loads showed model 1 also improved fatigue life ($3.3693{\times}10^5cycles$). This study provides important inputs to improve lower arm durability by modifying the arm configuration.

• Medical Lasers
• /
• v.9 no.2
• /
• pp.184-186
• /
• 2020

Lower eyelid blepharoplasty is a popular facial rejuvenation surgery that restores the infraorbital region. The procedure is performed by removing excessive fatty tissues, muscles, and other unnecessary structures. The structure of the eyelid differs from person to person and is quite complex; therefore, numerous side effects are expected. Common lower eyelid blepharoplasty complications are asymmetrical faces, retrobulbar hemorrhage, blurred vision, and ectropion. This paper reports a case of a prominent periorbital vein after lower eyelid blepharoplasty. The prominent periorbital vein after surgery is a rare side effect that has not been reported to the best of the author's knowledge. This case was treated with a long-pulse 1,064-nm neodymium:yttrium-aluminum-garnet laser.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.5 no.1
• /
• pp.123-132
• /
• 1985

The flexibility of base material gives considerable influences on seismic responses of a structure. The effects of relative stiffness between super-structure and base material on dynamic soil-structure interaction are evaluated by parametric studies. Two 5-story buildings are used for the study; one is shearwall structure with relatively higher fundamental frequency and the other is frame structure with relatively lower fundamental frequency. The structures are modeled as beam-sticks coupled with springs and dashpots representing the base material. Dynamic equilibrium equations of the soil-structure interaction system are sloved by mode superposition method using Rosset modal damping values. Soil-structure interaction effect is found to be major concern in seismic analysis of shearwall structure in most cases while it seldom becomes engineering problem in frame-type structure. It is also found that seismic responses at lower elevation of the super-structure are amplified though they decrease at higher elevation as soil-structure interaction effects of the system increase.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.48 no.6
• /
• pp.390-396
• /
• 2022

Cleft lip lower-lip deformity is a secondary deformity in patients who underwent primary cheiloplasty of the upper lip, characterized by an enlarged and anteriorly rotated lower lip. In these cases, soft-tissue imbalances remain even after skeletal correction with orthognathic surgery, and additional soft tissue treatment is required for lip harmony and esthetic facial balance in CLP (cleft lip palate) patients. This study describes three cases of transverse myomucosal excision of the lower lip for correction of cleft lip lower-lip deformity to restore facial esthetic balance. Each patient underwent orthognathic surgery, rhinoplasty, or upper lip revision cheiloplasty according to condition. Postoperatively, volume of the lower lip decreased and lip harmony was improved in all three patients. The surgeon should fully understand the anatomical structure around the lips and be able to evaluate overall harmony of the soft tissue. When a lower lip deformity is present, careful surgical planning and execution are important for each patient.

• Journal of architectural history
• /
• v.1 no.2 s.2
• /
• pp.172-182
• /
• 1992

The binary classification, Yin & Yang, can be shown in our culture. Yin & Yang thinking reveals the Up/Down (Principal/Subordinate) relation in space, and Before/After relation in time, and it shows the sequence of Contrast${\to}$Reconciliation & Unification${\to}$Contrast. For example, a follower is Yin against King, while Yang as a father against his son in our trational cognitive structure. With Left/Right, Front/Rear, and Upper/Lower, In/Out division is a basic body-space term to grasp the space position. In the traditional Korean house, when we go out from the deepest 'In', Anbang to Daechung, we may call Anbang 'In' and Daechung 'Out'. When from Daechung to Anmadang reversely, we call Daechung 'In' and Anmadang 'Out'. Namely, Daechung is both 'In' and 'Out'. This is a fallacy logic in view of western basic conception. 'The In/Out Structure, system of a series of inner spaces, is defined as a transformation of cognitive structure of Yin & Yang thinking to the Korean architectural space. The space structure is one of the important deep structure in Korean society.' The concept of the space structure, apperred in east Asia, can make humane space, for it is not a physical 'type' of typepology but related to cognitive structure of human thinking, The structure is applicable to space design in modern society, for the cognitive structure exists in living culture by transformation.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.3
• /
• pp.333-340
• /
• 2011

We evaluated the stress-reduction effect for different shapes of a composite adherend with or without a spew fillet. Six different single-lap joint specimens were modeled and assessed using nonlinear finite element analysis. Moreover, we investigated the effect of the stiffness ratio of the adherend and adhesive. The single-lap joint with normal tapering had the highest stress values, and the single-lap joint with reverse tapering and a spew fillet had the lowest stress values. The composite adherends with higher stiffness had lower stress values, and the adhesives with lower stiffness had lower stress values.