• Smart Structures and Systems
• /
• v.30 no.5
• /
• pp.521-535
• /
• 2022

Efficient management of deteriorating civil infrastructure is one of the most important research topics in many developed countries. In particular, the remote displacement measurement of bridges using linear variable differential transformers, global positioning systems, laser Doppler vibrometers, and computer vision technologies has been attempted extensively. This paper proposes a remote displacement measurement system using closed-circuit televisions (CCTVs) and a computer-vision-based method for in-situ bridge bearings having relatively large displacement due to temperature change in long term. The hardware of the system is composed of a reference target for displacement measurement, a CCTV to capture target images, a gateway to transmit images via a mobile network, and a central server to store and process transmitted images. The usage of CCTV capable of night vision capture and wireless data communication enable long-term 24-hour monitoring on wide range of bridge area. The computer vision algorithm to estimate displacement from the images involves image preprocessing for enhancing the circular features of the target, circular Hough transformation for detecting circles on the target in the whole field-of-view (FOV), and homography transformation for converting the movement of the target in the images into an actual expansion displacement. The simple target design and robust circle detection algorithm help to measure displacement using target images where the targets are far apart from each other. The proposed system is installed at the Tancheon Overpass located in Seoul, and field experiments are performed to evaluate the accuracy of circle detection and displacement measurements. The circle detection accuracy is evaluated using 28,542 images captured from 71 CCTVs installed at the testbed, and only 48 images (0.168%) fail to detect the circles on the target because of subpar imaging conditions. The accuracy of displacement measurement is evaluated using images captured for 17 days from three CCTVs; the average and root-mean-square errors are 0.10 and 0.131 mm, respectively, compared with a similar displacement measurement. The long-term operation of the system, as evaluated using 8-month data, shows high accuracy and stability of the proposed system.

• Journal of Venture Innovation
• /
• v.5 no.3
• /
• pp.19-40
• /
• 2022

The purpose of this study is to analyze and evaluate the role and merits and demerits of insurance agencies, which are the main sales channels of the domestic insurance market, from a neutral standpoint, and to present a roadmap by finding ways and tasks for the sustainable development of the insurance agency industry. Recently, criticisms and regulations on independent distribution channels have been strengthened due to deterioration in growth potential and profitability, and increase in civil complaints of insurance companies. In the 2000s, as the center of insurance sales channels shifted to GA and bancassurance, the supervisory authorities regarded the irrationality of project costs and recruitment fees as the root causes and announced a regulatory improvement plan. In view of these circumstance, the operating status, problems of domestic insurance agencies and their contribution to the insurance industry were reviewed. In addition, we tried to find a mid-to-long term development plan by analyzing the case of insurance agency operation in Japan. This study identified the operating status and contribution of insurance agencies in South Korea, and focused on the major status of the Japanese insurance agency industry, ways to improve management efficiency, and the status and role of self-regulatory organizations for insurance agencies. Based on this, it was proposed to improve the professionalism of the sales organization, introduce a company specializing in insurance sales, and to strengthen the status of the association of the insurance agency as for the development plan of the insurance agency industry in South Korea.

• Journal of Korea Water Resources Association
• /
• v.57 no.3
• /
• pp.165-179
• /
• 2024

It is crucial to have a comprehensive understanding of inundation and water cycle in urban areas for mitigating flood risks and sustainable water resources management. In this study, we developed a Cellular Automata-based integrated Water cycle model (CAW). A comparative analysis with physics-based and conventional cellular automata-based models was performed in an urban watershed in Portland, USA, to evaluate the adequacy of spatiotemporal inundation simulation in the context of a high-resolution setup. A high similarity was found in the maximum inundation maps by CAW and Weighted Cellular Automata 2 Dimension (WCA2D) model presumably due to the same diffuse wave assumption, showing an average Root-Mean-Square-Error (RMSE) value of 1.3 cm and high scores of binary pattern indices (HR 0.91, FAR 0.02, CSI 0.90). Furthermore, through multiple simulation experiments estimating the effects of land cover and soil conditions on inundation and infiltration, as the impermeability rate increased by 41%, the infiltration decreased by 54% (4.16 mm/m²) while the maximum inundation depth increased by 10% (2.19 mm/m²). It was expected that high-resolution integrated inundation and water cycle analysis considering various land cover and soil conditions in urban areas would be feasible using CAW.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.4
• /
• pp.468-476
• /
• 2020

This study was performed to establish light intensity conditions for producing stem cuttings for aeroponic systems suitable for seed potato production using a closed-type plant production system. Shoot tip cultured plantlets of 'Sumi' and 'Chubaek' potato (Solanum tuberosum L.) were acclimatized, cuttings were collected, and stem cuttings were planted. The seedlings were raised for 40 days at different LED light intensities (60, 120, 180, and 240 μmol·m^-2·s^-1), and were cultivated in an aeroponic system for 80 days. When stem cuttings were raised at 60 μmol·m^-2·s^-1 LED light intensity, the plant height was the longest, at 17.3 cm for 'Sumi' and 16.1 cm for 'Chubaek', and the number of nodes was the highest in both cultivars. The higher light intensities, produced smaller plants with fewer nodes. The leaf areas, SPAD values, and Fv/Fm values differed slightly between cultivars. The fresh weight of stem cuttings, and the production rate of healthy stem cuttings were the highest at 60 μmol·m^-2·s^-1. In the aeroponic system, seedlings raised at 60 μmol·m^-2·s^-1 with LED light intensity showed a difference between the cultivars, but the fresh weight of stems and leaves above the planting plate was the heaviest. In addition, below the planting plate the stem cuttings were longest and the root weight was heaviest at 60 μmol·m^-2·s^-1 LED light intensity. The number of stolons also differed between cultivars, but was greatest for seedlings raised at 60 μmol·m^-2·s^-1 LED light intensity, at 4.2/plant for 'Sumi' and 7.7/plant for 'Chubaek'. At 60 μmol·m^-2·s^-1 LED light intensity, the tuber number and total tuber weight were the best, but the higher the light intensity, the smaller the total tuber number and total tuber weight for both cultivars. In conclusion, when producing potato stem cuttings for aeroponic systems using a closed-type plant production system, the most suitable LED light intensity for raising seedlings was found to be 60 μmol·m^-2·s^-1.

• Korean Journal of Environmental Agriculture
• /
• v.20 no.2
• /
• pp.86-92
• /
• 2001

The current study was conducted to elucidate the optimum density of free-ranging ducks in a rice-duck farming system in terms of effects on duck behavior, and growth and yield of rice plants. Four paddy fields were used for this experiment, with 6, 9, 12 and 15 birds per plot, respectively. Ducklings at eight days of age were free ranged in experimental paddy plots (4.0 a each) on the 9th day after the transplantation of rice plants. Ducks were kept in the plot for seventy days, at which point rice plants reached the earing stage. Foraging, moving, working, resting, diving and pecking behaviors of the ducks were observed two times during the experimental period. Also, rice plant growth and yield according to the density of ducks per plot were examined. The foraging and moving behavior of free-ranging ducks in paddy fields for 12 hours during the daytime tended to be longer in the 12-bird plot, and working behavior was significantly (P<0.01) longer in the 12-bird plot than in the other three plots. The resting behavior was significantly (P<0.01) higher in the 9- and 15-bird plots than in the 12-bird plot. The frequency of moving behavior for 6 hours during the daytime in the 15-bird plot tended to be lower than that in the other three plots, but this difference was not significant. The amount of diving and pecking behavior in the 9-bird plot was significantly (P<0.05) higher than that in the other three plots, and the number of hills pecked tended to be higher with increasing of duck density. From thirty days after ducks were introduced to the paddy fields, the length of rice plants tended to be significantly (P<0.05) shorter in high free-ranging density plots as compared to low free-ranging density plots. The number of tillers per hill was not affected by the free-ranging density. The culm length of rice plants was significantly (P<0.05) shorter in the 12- and 15-bird plots than in the other two plots, however, the duck free-ranging density did not affect panicle length. The dry weight of the root of rice plants was increased with high free-ranging density, but there was no such increase in the top parts of the rice plants. The percent of rice plants badly damaged by free-ranging density tended to be lower in the order of 12-, 9-, 6- and 15-bird plots. The number of ears, ripening grains and crop yield per hill of rice plants in the 12-bird plot were significantly (P<0.05) higher than those of the other three plots. Therefore, the yield of each rice plant per 10 a was significantly increased in the 12-bird plot.

• Korean Journal of Environmental Agriculture
• /
• v.17 no.2
• /
• pp.174-181
• /
• 1998

In four citrus grow of Satsuma mandarin (rootstock of trifoliate orange) including two grove of organical management and two groves of conventional management, spores of arbuscular mycorrhizal(AM) fungi were identified and seasonal changes in spore density in soils and AM colonization of citrus roots were investigated. AM colonization in weeds found in the groves were also examined. Three species of Glomus (G.deserticola, G. vesiculiferum, G. rubiforme ) and one unknown species of Acaulospora were observed in all of the groves. Annual mean density of AM fungal spores were in the range of 10,000${\sim}$40,000 per 100g soil with more spores in the organically-managed groves. The least spores were observed in December in all groves, and the most spores in April in the organically-managed groves while in February or April in the conventionally- managed. Annual mean AM colonization more 27% of citrus root were observed in the organically-managed with the high peaks in April and October and the minimum in August, while mean colonization less than 15% in the conventionally-managed with the peak in February and the minimum in different times depending on groves and years. AM colonization corresponded to a sigmoidal curve consisting of a laf phase during winter and a subsequent increase in spring, then succeeded by a maximum, and then a decrease at the end of vegetation. Fungal spore density and AM colonization showed a parallel pattern during the sample period. The seasonality appeared to be related more to the phenology of the plant than to the soil factors. Generally more spore density and AM colonization were found in organically managed groves. AM colonization was not correlated with available P and organic matter content in soil in this field investigation. Among sixteen weed species found in the groves, Astrogalus sinicus of Leguminosae, Portulaca oleracea of Portulacaceae showed high colonization in all groves and they can be considered as a source of inoculumn and host plants for propagation of AM fungi.

• Journal of dental hygiene science
• /
• v.6 no.2
• /
• pp.133-138
• /
• 2006

To find out influence of water fluoridation program on the economic benefit effect, this study analyzed comparatively dental treatment indicators obtained from dental clinics at Sangdang-gu in Chenongju City, fluoridated community and Manan-gu in Anyang City, non-fluoridated community, from January 1, 2003 to the end of June, and the results are as follows: 1. If water fluoridation program is carried out in Anyang, non-fluoridated community, the number of treatment from caries and disease of tissues around dental pulp and root apex from age 6 to 18 for the first half of year 2003 is expected to decrease by 1,272, 636 for low estimation, and 1,908 for high estimation. And the treatment cost is expected to decrease by 40,888,000 Wons, 20,444,000 Wons for low estimation, and 61,333,000 Wons for high estimation. 2. Assuming that water fluoridation program is spread to all over the country, the number of treatment per year is expected to decrease by 2,492,018, 1,246,009 for low estimation, and 3,738,027 for high estimation. And the treatment cost is expected to decrease by 80,105,075,000 Wons, 40,052,537,000 Wons for low estimation and 120, 157,612,000 Wons for high estimation respectively. 3. For Yeong-un water supply management office which has 48,925 water supply personnel, the benefit/cost rate was 2.9 times, and for Jibuk water supply management office which has 239,751 water supply personnel, the benefit/cost rate was 9.0 times. As the water supply personnel increased, the cost increase of water fluoridation program was little and as the scale got large, the economic effect was very large. Improving national oral health is thought to be associated with expense retrenchment of oral health insurance financial. So it may need to extend using tap water to all the area of the country and additionally establish confidence through an active public relations and education of water fluoridation program.

• Korean Journal of Construction Engineering and Management
• /
• v.10 no.5
• /
• pp.37-46
• /
• 2009

This research will focus on the public agencies, designers, supervisors, building cooperation, and contractor who involved in urban development plan. By understanding the complexity and the priorities in urban development process, all problems of the urban development projects can be solved or improved. These priorities are specified using AHP (Analytic Hierarchy Process). A questionnaire survey is employed to identify the problems of urban development process and the methods of revitalizing urban in this research. Through the survey, 35 issues are drawn out. Factor analysis technique is applied to extract the underlying interrelationships possibly existing. Using latent root criterion and varimax rotation method, 9 factors are extracted(by using 34 issues after deleting 1 issue less than 0.4 of factor loading) These 9 factors named as PIF (Problem Improvement Factor) consist of integration estimation (PIF1), cooperation operation capability (PIF2), contractor corporation capability (PIF3), capital for infrastructure investment (PIF4), misunderstanding of effective land use (PIF5), financial capability (PIF6), obscure goal of project (PIF7), shortage of cooperation expertise (PIFS), administrative procedures (PIF9). PIF 6 is the most important factor and PIF 1 is the most widely effective factor to succeed urban land development projects. It is recognized that administrative office is most responsible for PIF1 cooperation is most responsible for PIF2, 7, 8 and 9; contractors is most responsible for PIF3 and PIF6; administrative agencies is most responsible for PIF4; cooperation and consultants are responsible for PIF5. From findings in this study, some suggestions are proposed for the revitalization methods of urban development projects through the land readjustment method.

• Journal of Bio-Environment Control
• /
• v.28 no.4
• /
• pp.376-387
• /
• 2019

Melons are mostly grown in soil, but it is susceptible to damage due to injury by continuous cropping such as Fusarium wilt and root rot. Hydroponic cultivation system can overcome the disadvantages of soil cultivation with precise nutrition management and a clean environment. When using the coir substrate, the most environmentally friendly organic substrate used for hydroponics, it is analyzed how the growth and fruit quality of the melon depends on the ratio of chips and dust and the amount of irrigation. The purpose of this study was to provide the basic data of melon hydroponics when cultivated in spring. The two types of the coir substrates used in the experiments were chip and dust ratios of 3 :7 and 5 : 5 respectively. The substrate with high dust ratios had excellent physical characteristics, such as container capacity and total porosity, and the drainage EC level showed a high value of $3.0-6.8dS{\cdot}m^{-1}$. When the amount of irrigation is provided based on the drainage rate, the group provided the nutrient solution on the basis of 10% drainage supplied 91 L per plant, which was reduced by about 30% compared to the group with the highest water supply. In addition, the total drainage showed less than 10 L per plant with a minimum water supply and was reduced by 30 - 70% in substrate with a high dust rates. In substrate with high water supply and high dust ratio, leaf growth and fruit enlargement were good, and the soluble solids content varies greatly from cultivar to cultivar. If you provided the amount of irrigation based on 10% drainage rate, the fruit weight will be decreased, but the amount of irrigation can be reduced. Therefore, it is considered that managing the water & nutrient properly taking into account the characteristics of coir substrate and cultivar can produce melon of uniform quality using hydroponics.

• Korean Journal of Heritage: History & Science
• /
• v.46 no.3
• /
• pp.114-133
• /
• 2013

This study aims to identify the natural damage of the Samcheonsaji Temple Site in Bukhansan National Park and to suggest the plans to minimize damage for the remains. The types of natural damage are classified into direct vegetation damage, indirect topographical damage, and artificial damage. The most popular causes of damage to temple sites include the roots of trees as direct vegetation damage and the soil erosion by rain or stream as topographical damage. Direct vegetation damage includes burial remains damaged by the root of trees and vines, but it is often observed that some trees have contributed to protection against collapse. Indirect topographical changes have damaged the ruins by soil erosion caused by floods or typhoons. Vegetation changes due to topographical reasons have also caused damage. Artificial reasons of damage include forestry operations and compaction by hikers. Based on the analysis of the findings, the following could be suggested as plans to resolve these problems: 1. Natural damage occurs slowly due to negligence. Therefore, it could be reduced by forestry improvement, including forest density control through thinning, planting to prevent landslides, maintaining grasslands nearby. 2. Deciduous broadleaf trees can be planted to reduce soil erosion by rainfall. It is necessary to maintain the density of forests at around $0.02{\sim}0.18trees/m^2$. 3. It would be good to grow Quercus spp and Carpinus spp or weaken the community of Robinia pseudoacacia and Pueraria lobata which disturb the ecosystem. Samcheonsaji Temple Site is located in Mt. Bukhan National Park that is a publicly owned property. Therefore, it is constantly maintained for natural preservation and vegetation management could be considered for the preservation of historical remains.