• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.601-608
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• 2019

In this study, the effect of hull appendages on the high-speed catamarans with reverse bow shapes is compared and analyzed by numerical analysis and circulating water tank model test. The reverse bow shape showed an improved wave shape by shifting the generation position of forward divergent wave to the stern direction and was effective in resistance and stable running posture (Kim et al., 2019). In the model test results of the running performance as the wave patterns and the change of the running posture due to the fin fitted with the inner side of the inverted bow and the interceptor, 1) Trim characteristics of the inverted bow 2) Improvement of superposition of inner wave by Fin 3) The trim control by the fin and the interceptor is considered to be effective in reducing the impact of the two hull connection decks (wetdeck).

• Advances in concrete construction
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• v.8 no.1
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• pp.21-31
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• 2019

The rich recipe of ultra high performance concrete (UHPC) offers the higher mechanical, durability and dense microstructure property. The variable like cement/sand ratio, amount of supplementary cementitious material, water/binder ratio, amount of fiber etc. alters the UHPC hardened properties to any extent. Therefore, to understand the effects of these variables on the performance of UHPC, inevitably a stage-wise development is required. In the present experimental study, the effect of sand/cement ratio, the addition of finer material (fly ash and quartz powder) and, hybrid fiber on the fresh, compressive and microstructural property of UHPC is evaluated. The experiment is conducted in three phases; the first phase evaluates the flow value and strength attainment of ingredients, the second phase evaluates the efficiency of finer materials (fly ash and quartz powder) to develop the UHPC and the third phase evaluate the effect of hybrid fiber on the flow value and strength of ultra high performance hybrid fiber reinforced concrete (UHP-HFRC). It has been seen that the addition of fly ash improves the flow value and compressive strength of UHPC as compared to quartz powder. Further, the usage of hybrid fiber in fly ash contained matrix decreases the flow value and improves the strength of the UHP-HFRC matrix. The dense interface between matrix and fiber and, a higher amount of calcium silicate hydrate (CSH) in fly ash contained UHP-HFRC is revealed by SEM and XRD respectively. The dense interface (bond between the fiber and the UHPC matrix) and the higher CSH formation are the reason for the improvement in the compressive strength of fly ash based UHP-HFRC. The differential thermal analysis (DTA/TGA) shows the similar type of mass loss pattern, however, the amount of mass loss differs in fly ash and quartz powder contained UHP-HFRC.

• Journal of Korean Society of Rural Planning
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• v.25 no.3
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• pp.115-128
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• 2019

The A1B scenario predicts that the mean air temperature of South Korea will rise up to $3.8^{\circ}C$ by 2071. However, the effects of ecosystem services are declining because of various environmental problems, including climate change, land use change, stream intensification, non-point pollution, and untreated garbage. Moreover, horticultural sites which have various ecosystem services suffer highly absorbed heat from the heat island phenomenon associated with climate change. Therefore, we analyzed the heat island phenomenon occurring in an protected horticulture estimated area in Saemanguem, South Korea. Using an advanced measurement method, we examined the air temperature change derived from water channels as well as open spaces. The CFD analysis of coverage ratio 85% design showed wind speed of 2.09 m/s and temperature of $38.07^{\circ}C$. At a coverage ratio of 70%, the wind speed was improved to 2.61 m/s and the temperature was improved to $36.89^{\circ}C$. In Alternative 2 with wetlands and trees, the wind speed was 2.71 m/s and the temperature was $35.90^{\circ}C$. When the coverage ratio decreases to 55%, the wind speed increases showing 3.06 m/s and the temperature decreases showing $35.18^{\circ}C$.

• Convergence Security Journal
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• v.18 no.1
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• pp.85-91
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• 2018

In this study, we design a marine environmental information service system with satellite images based on satellite images to reduce the damage caused by changes in the marine environment. The system provides satellite oceanographic information such as water temperature, chlorophyll, float, etc. as hierarchical texts, which is implemented as a unit module Web service so that it can be expanded in OpenAPI environment. And stability of system plug-in portability, service hours, data extraction precision and speed are used as a basis for diagnosing service stability. By securing the function and performance of the service system implemented in this study, it can be expanded to a complex technology that can customize the users by group by adding not only general services of existing systems operated by location but also information about a specific interested areas. Especially, various other items of interest including marine environment information are developed in modules, so we expect to be able to expand and service the system by plugging into the system and to spread it in technical linkage with the related institution information system.

• Geomechanics and Engineering
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• v.18 no.2
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• pp.179-188
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• 2019

This paper presents an experimental study to evaluate the effect of palm oil on the selected basic physical-chemical and geotechnical properties of kaolin. The experimental findings are further compared with literature outcomes investigating similar properties of fine grained soils subjected to contamination by different types of oils. To this end, palm oil was mixed with oven dried kaolin samples-aiding oil's interaction (coating) with dry particles first, in anticipation to emphasize the effect of oil on the properties of kaolin, which would be difficult to achieve otherwise. Oil content was limited to 40% by dry weight of kaolin, supplemented at intervals of 10% from clean kaolin samples. Observations highlight physical particle-to-particle bonding resulting in the formation of pseudo-silt sized clusters due to palm oil's interaction as evinced in the particle size distribution and SEM micrographs. These clusters, aided by water repellency property of the oil coating the kaolin particles, was analyzed to show notable variations in kaolin's consistency-measured as liquid and plastic limits. Furthermore, results from compaction tests indicates contribution of oil's viscosity on the compaction behavior of kaolin - showing decrease in the maximum dry unit weight (${\gamma}_{d,max}$) and optimum moisture content ($w_{opt}$) values with increasing oil contents, while their decrease rates were directly and inversely proportional in ${\gamma}_{d,max}$ and $w_{opt}$ values with oil contents respectively. Comparative study in similar terms, also validates this lower and higher decrease rates in ${\gamma}_{d,max}$ and $w_{opt}$ values of the fine grained soils respectively, when subjected to contamination by oil with higher viscosity.

• Korean Journal of Remote Sensing
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• v.35 no.3
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• pp.389-400
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• 2019

Level meters are non-invasively capable of measuring the level of the medium, and a growing variety of level meters are being used in the industry in connection with safety and maintenance. The level meter can be measured according to various kinds of medium such as solid medium such as coal, flour, rice and liquid medium such as water and petroleum. In order to reduce the error depending on the medium, the measurement using the Doppler Effect can compensate the measurement error, However, the number of signal processing steps is increased, the operation speed is further increased, the hardware complexity increases, and a high cost structure is required. In this paper, we propose a method to improve the signal processing operation structure of the remote measurement level meter to reduce the amount of computation and the resource usage of the required FPGA.

• Journal of Korean Academy of Nursing
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• v.49 no.3
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• pp.317-328
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• 2019

Purpose: The purpose of this study was to identify the effect of ghrelin on memory impairment in a rat model of vascular dementia induced by chronic cerebral hypoperfusion. Methods: Randomized controlled groups and the posttest design were used. We established the representative animal model of vascular dementia caused by bilateral common carotid artery occlusion and administered $80{\mu}g/kg$ ghrelin intraperitoneally for 4 weeks. First, behavioral studies were performed to evaluate spatial memory. Second, we used molecular biology techniques to determine whether ghrelin ameliorates the damage to the structure and function of the white matter and hippocampus, which are crucial to learning and memory. Results: Ghrelin improved the spatial memory impairment in the Y-maze and Morris water maze test. In the white matter, demyelination and atrophy of the corpus callosum were significantly decreased in the ghrelin-treated group. In the hippocampus, ghrelin increased the length of hippocampal microvessels and reduced the microvessels pathology. Further, we confirmed angiogenesis enhancement through the fact that ghrelin treatment increased vascular endothelial growth factor (VEGF)-related protein levels, which are the most powerful mediators of angiogenesis in the hippocampus. Conclusion: We found that ghrelin affected the damaged myelin sheaths and microvessels by increasing angiogenesis, which then led to neuroprotection and improved memory function. We suggest that further studies continue to accumulate evidence of the effect of ghrelin. Further, we believe that the development of therapeutic interventions that increase ghrelin may contribute to memory improvement in patients with vascular dementia.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.7
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• pp.1062-1068
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• 2019

Objective: For many generations, most species of farm animals have been subjected to intense and strictly targeted selection for improvement of their performance traits. This has led to substantial changes in animal anatomy and physiology, which resulted in considerable differences between the current animal breeds and their wild ancestors. The aim of the study was to determine whether there is breed-specific variability in behaviour as well as differences in emotional reactivity and preferences of laying hens. Methods: The investigations involved 50 Green-legged Partridge, 50 Polbar, and 50 Leghorn hens. All birds were kept in the same conditions, and the behavioural tests were carried out at 30 weeks of age. We used the tonic immobility test and a modified open-field test including such objects as water, commercial feed, feed enriched with cereal grains, finely cut straw, and insect larvae, a sandpit, a mirror, and a shelter imitating a hen nest. Results: The research results demonstrate that the birds of the analysed breeds differ not only in the excitability and emotional reactivity but, importantly, also in the preferences for environment-enriching elements. Ensuring hens' well-being should therefore be based on environmental modifications that will facilitate acquisition of essential elements of chickens' behaviour. The greatest emotional reactivity was found in the Leghorn breed, which may be a result of correlated selection aimed at an increase in chicken productivity. Conclusion: The differences in the behaviour of the birds from the analysed breeds indicate that laying hens cannot be regarded as one group of animals with the same environmental requirements.

• Geomechanics and Engineering
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• v.17 no.5
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• pp.485-496
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• 2019

Sealing of leakage in waterfront or water-retaining structures is one of the major issues in geotechnical engineering practices. With demands for biological methods as sustainable ground improvement techniques, bioclogging, defined as the reduction in hydraulic conductivity of soils caused by microbial activities, has been considered as an alternative to the chemical grout techniques for its economic advantages and eco-friendliness of microbial by-products. This study investigated the feasibility of bioaugmentation and biostimulation methods to induce fermentation-based bioclogging effect in coarse sands. In the bioaugmentation experiments, effects of various parameters and conditions, including grain size, pH, and biogenic gas generation, on hydraulic conductivity reduction were examined through a series of column experiments while Leuconostoc mesenteroides, which produce an insoluble biopolymer called dextran, was used as the model bacteria. The column test results demonstrate that the accumulation of bacterial biopolymer can readily reduce the hydraulic conductivity by three-to-four orders of magnitudes or by 99.9-99.99% in well-controlled environments. In the biostimulation experiments, two inoculums of indigenous soil bacteria sampled from waterfront embankments were prepared and their bioclogging efficiency was examined. With one inoculum containing species capable of fermentation and biopolymer production, the hydraulic conductivity reduction by two orders of magnitude was achieved, however, no clogging was found with the other inoculum. This implies that presence of indigenous species capable of biopolymer production and their population, if any, play a key role in causing bioclogging, because of competition with other indigenous bacteria. The presented results provide fundamental insights into the bacterial biopolymer formation mechanism, its effect on soil permeability, and potential of engineering bacterial clogging in subsurface.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.655-661
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• 2020

SGM (Semi Global Matching) can be used to find all the conjugate points between stereo images. Therefore, it enables high-density DSM (Digital Surface Model) production from high-resolution satellite images. However, water, shadows, and occlusion areas cause mismatching of the surrounding points in this method. Particularly, in buildings with large-parallax and elongated-shapes such as a Korean style apartment, it is difficult to reconstruct the 3D building even if the SGM method is applied to a high-resolution 50cm satellite image. This study proposed and performed the SGM technique with a classified image and an edge image from the IKONOS-2 satellite stereo-image with a 1m resolution to produce DSM. It was compared with the DSMs from the general SGM and the high-density ABM (Area Based Matching) matching of ERDAS software. The results of the apartment DSM by the proposed method were the best in the test area. As a result, despite the image having a resolution of 1m, the outline of the building DSM could be expressed more clearly than the existing method.