• Earthquakes and Structures
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• v.12 no.6
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• pp.699-712
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• 2017

This study evaluates the effectiveness of a newly developed retrofitting scheme for masonry-infilled non-ductile RC frames experimentally and by numerical simulation. The technique focuses on modifying the load path and yield mechanism of the infilled frame to enhance the ductility. A vertical gap between the column and the infill panel was strategically introduced so that no shear force is directly transferred to the column. Steel brackets and small vertical steel members were then provided to transfer the interactive forces between the RC frame and the masonry panel. Wire meshes and high-strength mortar were provided in areas with high stress concentration and in the panel to further reduce damage. Cyclic load tests on a large-scale specimen of a single-bay, single-story, masonry-infilled RC frame were carried out. Based on those tests, the retrofitting scheme provided significant improvement, especially in terms of ductility enhancement. All retrofitted specimens clearly exhibited much better performances than those stipulated in building standards for masonry-infilled structures. A macro-scale computer model based on a diagonal-strut concept was also developed for predicting the global behavior of the retrofitted masonry-infilled frames. This proposed model was effectively used to evaluate the global responses of the test specimens with acceptable accuracy, especially in terms of strength, stiffness and damage condition.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.660-669
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• 1989

The strain distribution in a wide strip drawn through a wedge-shaped die is obtained from the numerical integration of strain increments along the flow path of material points in the slipline field for a non-hardening material under the plane strain condition. It is shown that the strain in the surface layer increases with friction and that the strain at the mid-plane is a function of area reduction only. The redundant deformation factor, obtained from the average strain in a drawn strip, increases with friction. For the workability analysis of a strip drawing process, the strain states along with hydrostatic stresses are needed for the evaluation of a damage function based on the hole-growth mechanism of ductile fracture. The critical maximum of the damage function is assumed to be a material constant. As a result, mid-plane cracking is likely to occur in a process at a small reduction, with a large die angle, and in poor lubrication. Distortions of an initially transverse line are also calculated.

• Asian Journal of Business Environment
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• v.11 no.1
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• pp.39-50
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• 2021

Purpose: This study seeks to establish the environmental damage theory applicable to Kenya. The analysis is based on annual data drawn from World Bank on carbon dioxide emissions (CO2e) and gross domestic product per capita (GDPPC) for Kenya spanning 1963 to 2017. Research Methodology: The study adopts explanatory research design and autoregressive distributed lag model for analysis. Results: The results revealed a coefficient of -0.017 for GDPPC and 0.004 for GDPPC squared indicating that economic growth has negative effect on CO2e in the initial stages of growth but positive effect in the high growth regime with the marginal effect being higher in the initial growth regime. The findings suggest a U-shaped relationship consistent with Brundtland Curve Hypothesis (BCH). Conclusions: The findings emphasize the need for sustainable development path that enables present generations to meet own needs without compromising the capacity of future generations to meet their own. Sustainable development may include, investment in renewable energies like wind, solar and adoption of energy efficient technologies in production and manufacturing. The study concludes that BCH is applicable to Kenya and that developing affordable and effective mechanisms to boost sustainable development implementation is necessary to decrease the anthropogenic impact in the environment without any attendant reduction in the economic growth.

• Journal of Environmental Science International
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• v.30 no.3
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• pp.257-266
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• 2021

This study explored measures to reduce noise applicable to Gimhae international airport centering on densely packed housing areas. Especially, as for measures to relieve noise damage on the densely packed housing areas in Gimhae-si, the noise reduction effect is expected to be doubled if the west runway (36L/18R) is used as the preferred runway for the 36 direction takeoff, as well as if the flight bypasses the densely packed housing areas by means of sophisticated navigation using the area navigation (RNAV) procedure based on performance-based navigation (PBN). Takeoff toward the south connects the flight path to the South Sea which has comparatively low noise impact, relieving noise damage on the densely packed housing areas (apartment complexes in Naeoe-dong of Gimhae-si, etc.) near the northern end of the runway. The operation of the runway displaced threshold is currently being implemented on the west runway (36L/18R) of Gimhae international airport. It has been found that swing landing in spring and summer when the wind blows from the south has a noise reduction effect on the noise sensitive areas at the side and end of the west runway (Gangdong-dong and Jukdong-dong of Gangseo-gu and Buram-dong of Gimhae-si, etc.).

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.234-234
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• 2017

Recent abnormal weather, especially continued rainfall during sowing season causes difficulty in proper sowing of wheat and delayed sowing after November 15 is concerned about freezing damage during winter, resulting in reduction of wheat yield. To correspond government policy of crop sufficiency improvement and produce and supply raw wheat and barley steadily, expansion of cultivation area is necessary and spring sowing of wheat is required. To obtain basic information on the improvement of spring sown wheat and barley production, comparison and path coefficients analysis was conducted for yield and yield related components from autumn and spring sown wheat and barley. Path analyses were known as very useful in clarifying the effects of yield components on grain yield formation, which were not accurately reflected in simple correlation anaylses. Most cultivated 5 wheat and 9 barley cultivars were sown on October and February at Cheon-ju province according to standard sowing method. For the spring sowing of wheat and barley, the varieties having vernalization degree I~III are seeded in the mid of February and seeding rate is 200~250kg/ha which is increased by 25% than autumn sowing. N-fertilizer of 95 kg/ha and the same amount of P, K dressed in autumn are applied at once as basal fertilizer. The magnitude of direct effect in each yield components on yield was in sequence as follows. In autumn wheat, grain number per $spike{\geq}$ the number of spike per $m^2$>1000-grain weight and in spring wheat, grain number per $ spike{\geq}the$ number of spike per $m^2$> 1000-grain weight. In autumn naked barley, 1000-grain weight> the number of spike per $m^2$, grain number per spike and in spring barely, the number of spike per $m^2$> grain number per spike > 1000-grain weight. In autumn covered barley, grain number per spike>the number of spike per $m^2$ and in spring coverd barley, the number of spike per $m^2$> grain number per spike, 1000-grain weight. In autumn malt barley, the number of spike per $m^2$>1000-grain weight and in spring malt barley, the direct effects of three yield components were similar. According to the path analysis of yield components for spring sown wheat and barley, it was suggested that adequate number of spike per $m^2$ was most important factor for yield increase.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.4
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• pp.117-122
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• 2021

In recent years, human damage and loss of money due to various disasters such as typhoons, earthquakes, forest fires, landslides, and wars are steadily occurring, and a lot of manpower and funds are required to prevent and recover them. In this paper, we designed and developed a disaster drone system based on artificial intelligence in order to monitor these various disaster situations in advance and to quickly recognize and respond to disaster occurrence. In this study, multiple disaster drones are used in areas where it is difficult for humans to monitor, and each drone performs an efficient search with an optimal path by applying a deep learning-based optimal path algorithm. In addition, in order to solve the problem of insufficient battery capacity, which is a fundamental problem of drones, the optimal route of each drone is determined using Ant Colony Optimization (ACO) technology. In order to implement the proposed system, it was applied to a forest fire situation among various disaster situations, and a forest fire map was created based on the transmitted data, and a forest fire map was visually shown to the fire fighters dispatched by a drone equipped with a beam projector. In the proposed system, multiple drones can detect a disaster situation in a short time by simultaneously performing optimal path search and object recognition. Based on this research, it can be used to build disaster drone infrastructure, search for victims (sea, mountain, jungle), self-extinguishing fire using drones, and security drones.

• Journal of the Korean Geosynthetics Society
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• v.23 no.1
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• pp.49-60
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• 2024

Recently, the frequency and intensity of typhoon-induced wave loading are increasing due to changed marine environments such as climate change. In addition, frequent earthquakes are causing a lot of damage around the world, including in Japan, Chile, Haiti, China, and Indonesia. In Korea, damage from typhoons has also been increasing since the 2000s, and the frequency and intensity of earthquakes are also increasing. Korea is surrounded by sea on three sides, so typhoons can cause a lot of damage to coastal structures, and earthquakes also cause a lot of damage to coastal structures. As such, the frequency and intensity of typhoon-induced wave loading and earthquakes are increasing both domestically and internationally, but there is no research linking typhoons and earthquakes. Therefore, in this study, numerical analysis was performed for a total of four cases by linking typhoon waves and earthquakes to the caisson breakwater. Numerical analysis was performed by applying wave loads in Case 1 and seismic wave in Case 2, seismic wave after wave loads in Case 3, and wave loads after seismic wave in Case 4. As a result of the numerical analysis, it was confirmed that in Case 3 and Case 4, which linked a typhoon and earthquakes, the damage caused by each load increased compared to Case 1 and Case 2 because the load was applied while the existing ground strength was reduced. In addition, it was confirmed that the greatest damage occurred in Case 3, in which seismic wave were applied after the wave loads.

• Earthquakes and Structures
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• v.10 no.5
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• pp.1089-1109
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• 2016

Modified two-surface model (M2SM) is one of the steel elasto-plastic hysteretic constitutive models that consider both analysis accuracy and efficiency. However, when M2SM is used for complex strain history, sometimes the results are irrational due to the limitation of stress-strain path judgment. In this paper, the defect of M2SM was re-modified by improving the judgment of stress-strain paths. The accuracy and applicability of the improved method were verified on both material and structural level. Based on this improvement, the nonlinear time-history analysis was carried out for a deck-through steel arch bridge with a 200 m-long span under the ground motions of Chi-Chi earthquake and Niigata earthquake. In the analysis, we compared the results obtained by hysteretic constitutive models of improved two-surface model (I2SM) presented in this paper, M2SM and the bilinear kinematic hardening model (BKHM). Results show that, although the analysis precision of displacement response of different steel hysteretic models differs little from each other, the stress-strain responses of the structure are affected by steel hysteretic models apparently. The difference between the stress-strain responses obtained by I2SM and M2SM cannot be neglected. In significantly damaged areas, BKHM gives smaller stress result and obviously different strain response compared with I2SM and M2SM, and tends to overestimate the effect of hysteretic energy dissipation. Moreover, at some position with severe damage, BKHM may underestimate the size of seismic damaged areas. Different steel hysteretic models also have influences on structural damage evaluation results based on deformation behavior and low cycle fatigue, and may lead to completely different judgment of failure, especially in severely damaged areas.

• Journal of Korean Medical classics
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• v.26 no.4
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• pp.105-116
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• 2013

Objective : If the penetration ratio of the intestinal mucosa is increased, the toxic or unhealthy materials - which should not be absorbed into our bodies - will be come into our bodies. They cause a sort of anti-toxic response or confusion of the immune system, and ultimately bring various types of diseases. This syndrome is related "Poison in Excrement" or "Internal Damage(內傷發癍)" and Leaky Gut Syndrome, so I will study on the relationship between them. Method : Study on the relationship between Dae-Jang-Jung-gyeok and Leaky Gut Syndrome. Result : Korean doctors in ancient times called this syndrome "Poison in Excrement" or "Internal Damage(內傷發癍)" and treated it with "Dae-Jang-Jung-Gyeok(大腸正格)". Leaky Gut Syndrome is a sort of clinical lesion, which allows foreign and harmful toxins in and results in a disorder of the immune system due to the leaking intestinal mucosa. Conclusion : Based upon the analyses, Dae-Jang-Jung-Gyeok and Leaky Gut Syndrome are closely related. Therefore diseases caused by the Leaky Gut Syndrome might be expected to be cured by Dae-Jang-Jung-Gyeok. Particularly the use of treatments for self-immune diseases and allergic diseases such as atopyic dermatitis and articular rheumatism should be expected to reveal a new path of treatment for other disorders such as Leaky Gut Syndrome.

• Journal of the Korean Institute of Gas
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• v.24 no.2
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• pp.36-43
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• 2020

Gas system fire extinguishing equipment is a very economically useful facility, but if it is not used for a long period of time after installing the equipment, there is possibility of rupture due to corrosion of containers and operation errors of equipment systems, and this is very dangerous. However, it is impossible to experiment to check whether the equipment is operating normally. If gas is temporarily released into the enclosed space due to rupture and malfunction, it can cause serious human damage due to gas suffocation. In this study, based on the suffocation death accident of gas system fire extinguishing facility, the inflow path of released gas and the possibility of death and time to death were estimated using a 3D scan and FLACS.