• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.83-88
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• 2004

Recently, High Tensile Steel is adapt to thin plate on the steel structure and marine structure is used widely. It is possible for buckling happens great. Specially, Initial deflection of ship structure happens in place absence necessarily by heat processing of welding or cutting etc. This Initial Deflection is exerted negative impact when thin plate absence complicated nonlinear behaviour accompanied secondary buckling. As a result, must idealize initial deflection that occurrence is possible to endow stability and accuracy in the hull structure or marine structure and reflect in early structure design considering secondary buckling. Longi direction of compressive load interacts and analyzed finite element series analysis that apply various kinds initial deflection shape measured actually on occasion that is arranged simply supported condition in this research. Applied ANSYS (elasto-plasticity large deformation finite element method) to be mediocrity finite element program for analysis method and analysis control used in Newton-Raphson method ＆ Arc-length method.

• Atmosphere
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• v.26 no.3
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• pp.401-412
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• 2016

A 3D sonic anemometer has been installed at Yongpyong alpine slope since Oct. 23th 2014 to observe the slope winds and to analyze turbulent characteristics with the change in surface cover (grass and snow) and the synoptic wind strength. Eddy covariance method has been applied to calculate the turbulent quantity after coordinate transformation of a planar-fit rotation. We have carefully selected 3 good episodes in the winter season (23 October 2014 to 28 February 2015) for each category (9 days in total), such as grass and snow covers in case of weak synoptic wind condition, and grass cover of strong synoptic wind. The diurnal variations of the slope winds were well developed like the upslope wind in the daytime and downslope wind in the nighttime for both surface covers (grass and snow) in the weak synoptic forcing, when accordingly both heat and momentum fluxes significantly increased in the daytime and decreased in the nighttime. Meanwhile, diurnal variation of heat flux was not present on the snow cover probably in associated with significant fraction of sunlight reflection due to high albedo especially during the daytime in comparison to those on the grass cover. In the strong synoptic regime, the most dominant feature at Yongpyong, only the southeasterly downslope winds were steadily generated irrespective of day and night with significant increases in momentum flux and turbulent kinetic energy as well, which could suggest that local circulations are suppressed by the synoptic scale forcing. In spite of only one season analysis applied to the limited domain, this kind of an observation-based study will provide the basis for understanding of the local wind circulation in the complex mountain domain such as Gangwon in Korea.

• Structural Engineering and Mechanics
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• v.76 no.1
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• pp.83-99
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• 2020

Shear walls are structural members in buildings that are used extensively in reinforced concrete frame buildings, and almost exclusively in the UK, regardless of whether or not they are actually required. In recent years, the UK construction industry, led by the Concrete Centre, has questioned the need for such structural elements in low to mid-rise reinforced concrete frame buildings. In this context, a typical modern, 5-storey residential building is studied, and its existing shear walls are replaced with columns as used elsewhere in the building. The aim is to investigate the impact of several design variables, including concrete grade, column size, column shape and slab thickness, on the building's structural performance, considering two punching shear limits (V_Ed/V_Rd,c), lateral drift and accelerations, to evaluate its maximum possible height under wind actions without the inclusion of shear walls. To facilitate this study, a numerical model has been developed using the ETABS software. The results demonstrate that the building examined does not require shear walls in the design and has no lateral displacement or acceleration issues. In fact, with further analysis, it is shown that a similar building could be constructed up to 13 and 16 storeys high for 2 and 2.5 punching shear ratios (V_Ed/V_Rd,c), respectively, with adequate serviceability and strength, without the need for shear walls, albeit with thicker columns.

• Journal of Environmental Science International
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• v.19 no.6
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• pp.689-701
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• 2010

The effects of high-resolution wind profiler (HWP) data on the wind distributions were evaluated in two different coastal areas during the study period (23-26 August, 2007), indicating weak-gradient flows. The analysis was performed using the Weather Research and Forecasting (WRF) model coupled with a three-dimensional variational (3DVAR) data assimilation system. For the comparison purpose, two coastal regions were selected as: a southwestern coastal (SWC) region characterized by a complex shoreline and a eastern coastal (EC) region surrounding a simple coastline and high mountains. The influence of data assimilation using the HWP data on the wind distributions in the SWC region was moderately higher than that of the EC region. In comparison between the wind speed and direction in the two coastal areas, the application of the HWP data contributed to improvement of the wind direction distribution in the SWC region and the wind strength in the EC region, respectively. This study suggests that the application of the HWP data exerts a large impact on the change in wind distributions over the sea and thus can contribute to the solution to lack of satellite and buoy data with their observational uncertainty.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.157-171
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• 2009

A 151 storey super high-rise building located in an area of reclaimed land constructed over soft marine clay in Songdo, Korea is currently under design. This paper describes the design process of the foundation system of the supertall tower, which is required to support the large building vertical and lateral loads and to restrain the horizontal displacement due to wind and seismic forces. The behaviour of the foundation system due to these loads and foundation stiffness influence the design of the building super structure, displacement of the tower, as well as the raft foundation design. Therefore, the design takes in account the interactions between soil, foundation and super structure, so as to achieve a safe and efficient building performance. The site lies entirely within an area of reclamation underlain by up to 20m of soft to firm marine silty clay, which overlies residual soil and a profile of weathered rock. The nature of the foundation rock materials are highly complex and are interpreted as possible roof pendant metamorphic rocks, which within about 50m from the surface have been affected by weathering which has reduced their strength. The presence of closely spaced joints, sheared and crushed zones within the rock has resulted in deeper areas of weathering of over 80m present within the building footprint. The foundation design process described includes the initial stages of geotechnical site characterization using the results of investigation boreholes and geotechnical parameter selection, and a series of detailed two- and three-dimensional numerical analysis for the Tower foundation comprising over 172 bored piles of varying length. The effect of the overall foundation stiffness and rotation under wind and seismic load is also discussed since the foundation rotation has a direct impact on the overall displacement of the tower.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.61-71
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• 2023

Purpose : Energy bars are increasingly popular among active individuals, yet their timing and nutrient combinations' impact on exercise adaptation remains unclear. This study aims to address this knowledge gap by investigating whether the combination of pre- and post-workout supplementation can synergistically enhance fitness and alleviate fatigue in trained CrossFit participants. Investigate if combining pre- and post-workout supplements can enhance fitness and blood lactate management in trained CrossFit participants, potentially improving exercise performance for this group. Methods : In a randomized crossover study, 20 trained CrossFit individuals (11 males, 9 females) completed thrice-weekly 60-minute CrossFit sessions for 3 weeks, with a one-week washout period. Participants were randomly assigned to either a chocolate bar group (CH, 45 g, 225 kcal) or an energy bar group (ES, 48 g, 238 kcal, with protein, caffeine, taurine, and BCAAs). For one week, participants consumed two bars of their assigned supplement five minutes before and after workouts. After a washout period, they switched supplements. Blood lactate levels and a visual analog scale (VAS) were assessed before, immediately after, and 30 minutes post-workout. Fitness tests (hand grip, broad jump, sit-ups) were conducted at baseline and 30 minutes post-final workout. Data were analyzed using two-way repeated measures ANOVA (p<.05), 95 % confidence intervals, and magnitude inferences. Results : Hand grip strength (t=-5.60, p=.000), broad jump (t=-3.43, p=.003) and sit up (t=-3.94, p=.001) were significantly increased in the ES group. Compared to CH group, there was a significant time and group interactions for blood lactate level (F=5.51, p=.008) and VAS(F=31.67, p=.000) in the ES group. Conclusion : Pre- and post-workout energy bar supplementation may have a beneficial effect on blood lactate clearance and fitness in trained CrossFit individual. The combination of proprietary supplements taken may provide benefits for removing the blood lactate during high-intensity functional exercise.

• Journal of dental hygiene science
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• v.24 no.3
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• pp.152-159
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• 2024

Background: As interest in health increases, the number of people engaging in weight training to enhance muscle strength and muscle mass is on the rise. High-intensity weight training has been reported to induce tooth clenching habits, leading to tooth damage and temporomandibular joint (TMJ) abnormalities. Consequently, it is essential to investigate the impact of weight training accompanied by tooth clenching on oral health and to develop guidelines based on these findings. Methods: The study included male participants aged 25 years and older, comprising 15 non-exercisers and 15 professional fitness trainers who have been engaged in weight training for over 5 years. Data were collected using a self-administered questionnaire to gather information on age, exercise experience, total weight lifted in three major weight training exercises (deadlift, bench press, and squat), and teeth clenching habits. Additionally, examinations for tooth cracks and fractures, TMJ noise and pain, maximum mouth opening, occlusal force, and occlusal contact area were conducted. Results: Compared to non-exercisers, professional fitness trainers who have been engaged in weight training for over 5 years exhibited a higher prevalence of teeth clenching habits. While there were no significant differences between the two groups in occlusal contact area and the extent of tooth fractures, there were significant differences in occlusal force and the degree of tooth cracks. Furthermore, unlike joint noise and TMJ pain, the maximum mouth opening was significantly reduced in professional fitness trainers compared to non-exercisers. Conclusion: Our study suggests that the continuation of high-intensity exercise, which induces teeth clenching habits, may cause tooth damage and TMJ disorders.

• Strategy21
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• s.43
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• pp.5-28
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• 2018

The tensions between the U.S and China, which form the two pillars of the G2 era, seem to have persisted even after the Trump administration inaugurated. The strong confrontation between the two in recent foreign security issues may drive to develop an inadvertent military conflict, and it is high likely to occur in the maritime are. The purpose of this study is not only to analyze the balance of modernized naval forces in the PLAN through naval strategy changes and weapons system modernization trend, but also to predict the impact of the geographical proximity difference on the balance of naval forces in the disputed areas. It examined the impact of distance and geography on naval power by assessing the modernization pattern of the PLAN and capabilities in the context of two scenarios at different distances from China by 2020: one centered on Taiwan and the other on the Spratly Islands. The PLAN's strategy had impact on operational concept and forces construction. First, from the viewpoint of operation operational concept, it can be seen that the passive defense is changing into active defense. Second, in terms of power construction, it can threaten the surface and submarines of U.S power from a distance. And they generated follow three features; The ocean is not the focus of Chinese submarines, Horizontal and vertical expansion of Chinese naval vessels, The improvement of the suppression ability as the Chinese naval modernization ratio increases. The strength of the PLAN is dominant over the U.S in terms of reserves, and it can complement the qualitative deterioration by utilizing nearby bases in the vicinity of the mainland, such as the Taiwan Strait. However, due to the shortage of aircraft carriers, there is a possibility that it will take some time to secure the advantage of air and ocean in the amphibious operation. Therefore, as the dispute is prolonged, China may fail to achieve its original goal. In addition, the lack of cutting edge Commanding Ships may bring to weaken the C2 capabilities. At results, it is expected that PLAN will not be able to have a superiority in the short term due to lagging behind U.S advanced technology. Nevertheless, PLAN has strengthened its naval power through modernization sufficiently and it is highly likely to use force. Especially, it is more likely in the region where the naval power operation like the Taiwan Strait is possible with the almost equality to that of the United States. China will continue to use its naval forces to achieve a rapid and decisive victory over U.S in the close area from the land.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.2
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• pp.133-142
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• 2022

The purpose of this study is to develop an impact crusher with a radial rotating plate installed at the bottom, which is a shock absorber that can produce high-quality recycled coarse aggregate for concrete and to verify the effect of improving the quality performance of recycled coarse aggregate and its applicability through concrete tests. As a result, it showed improved quality in all items such as absolute dry density, absorption rate, abrasion resistance, Particle shape judgment rate, amount lost in the 0.08 mm sieve passing test, alkali aggregate reaction, clay mass, stability, and impurity content, and it was found to meet the criteria of recycled aggregate quality standards. In addition, the air volume and slump of concrete to which recycled coarse aggregate is applied meet all domestic standards. According to the test results of the compressive strength characteristics by age of concrete according to the mixing ratio of the recycled coarse aggregate, it was confirmed that the mixing ratio of the recycled coarse aggregate was applicable up to 60 %.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.666-671
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• 2018

A honeycomb panel is a plate made by attaching two surface plateson eitherside of a honeycomb core. The honeycomb plate hasexcellent specific strength and energy absorption and is suitable for use in regions where good impact resistance is required. Recently, with the increasing the need for a lightweight design to facilitate transportation, numerous studies have been conducted using aluminum honeycomb plates as body materials for vehicles such as automobiles and high-speed trains. In addition, honeycomb plates have excellent sound deadening properties, as well as excellent heat insulation and durability. Savings in weight using lightweight materials such as aluminum alloy for honeycomb panel's skin can lead to increase fuel economy and reduction in air pollution. In this study, in order to improve the design technology of the honeycomb plate material, the manufacturing technology of the aluminum honeycomb core and honeycomb plate material and various mechanical properties of the honeycomb plate were evaluated. From the results, it was found that the design of the manufacturing process of the aluminum honeycomb plate, as well as itsproduction and characteristics, were improved. The resulting excellent energy absorption capability of the honeycomb plate was due to the repetitive core buckling, indicating that the higher the compressive strength, the higher the strength per bonded area.