• Smart Structures and Systems
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• v.30 no.5
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• pp.521-535
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• 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 the Korean Institute of Traditional Landscape Architecture
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• v.41 no.3
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• pp.59-66
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• 2023

This study attempts to examine the process of establishing a Japanese-style garden in the modern period through the perspectives of garden designers, spatial composition, spatial components, and materials used in their works, and to use it as data for embodying the identity of Korean garden. The results are as follows: First, by incorporating elements associated with Koreanness into the modern garden culture, there are differences in location, presence, and subjectivity when compared to Japan. This reflects Japan's relatively seamless cultural continuity compared to Korea's cultural disconnection during the modern period. Second, prior to the modern period, Japan's garden culture spread and continued to develop throughout the country without significant interruptions. However, during the modern period, the Meiji government promoted the policy of 'civilization and enlightenment (Bunmei-kaika, 文明開化)' and introduced advanced European and American civilizations, leading to the popularity of Western-style architectural techniques. Unfortunately, the rapid introduction of Western culture caused the traditional Japanese culture to be overshadowed. In 1879, British architect Josiah Condor guided Japanese architects and introduced atelier and traditional designs of Japanese gardens into the design. The garden style of Ogawa Jihei VII, a garden designer in Kyoto during the Meiji and Taisho periods, was accepted by influential political and business leaders who sought to preserve Japan's traditional culture. And a protection system of garden was established through the preparation of various laws and regulations. Third, as a comprehensive analysis of Japanese modern gardens, the examination of garden designers, Japanese components, materials, elements, and the Japanese-style showed that Yamagata Aritomo, Ogawa Jihei VII, and Mirei Shigemori were representative garden designers who preserved the Japanese-style in their gardens. They introduced features such as the creation of a Daejicheon(大池泉) garden, which involves a large pond on a spacious land, as well as the naturalistic borrowed scenery method and water flow. Key components of Japanese-style gardens include the use of turf, winding garden paths, and the variation of plant species. Fourth, an analysis of the Japanese-style elements in the target sites revealed that the use of flowing water had the highest occurrence at 47.06% among the individual elements of spatial composition. Daejicheon and naturalistic borrowed scenery were also shown. The use of turf and winding paths were at 65.88% and 78.82%, respectively. The alteration of tree species was relatively less common at 28.24% compared to the application of turf or winding paths. Fifth, it is essential to discover more gardens from the modern period and meticulously document the creators or owners of the gardens, the spatial composition, spatial components, and materials used. This information will be invaluable in uncovering the identity of our own gardens. This study was conducted based on the analysis of the process of establishing the Japanese-style during Japan's modern period, utilizing examples of garden designers and gardens. While this study has limitations, such as the absence of in-depth research and more case studies or specific techniques, it sets the stage for future exploration.

• Korean journal of food and cookery science
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• v.11 no.4
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• pp.356-361
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• 1995

This study was conducted to know the quality of marketed green teas which were devided into high, middle and low grade according to the price. we examined the content of water, ash, total nitrogen, tannin, caffeine, chlorophyll and color value and did sensory evaluation. The results were as follows: 1) The content of water was 2.17-3.67％ and content of ash was 4.50-5.17％, there were no significant difference in each grade. 2) The content of total nitrogen was 4.38％ in high grade, 4.60％ in middle grade and 4.68％ in low grade. 3) The content of tannin was 11.09％ in high grade, 14.22％ in middle grade and 14.44％ in low grade, middle and low grade were significantly higher than high grade. 4) The nitrogen rate to tannin (N/T) was 39.5％ in high grade, 32.6％ in middle grade and 32.70％ in low grade, N/T rate of high grade was significantly highest than others. 5) The content of caffeine is 1.78％ in high grade, 1.32％ in middle grade and 0.92％ in low grade, high and middle grade were significantly higher than low grade. 6) The content of total chlorophyll is 297.37 mg％ in high grade, 192.89 mg％ in middle grade and 204.79 mg％ in low grade, chlorophyll a was 69.23 mg％ in high grade, 51.99 mg％ in middle grade and 63.42 mg％ in low grade, and chlorophyll b was 228.47 mg％ in high grade, 131.21 mg％ in middle grade and 141.63 mg％ in low grade. 7) Yellow value of high and middle grade were significantly higher than low grade, but blue and red value were no significant diffrence in groups. 8) In sensory evaluation, appearance, taste, odor of high grade were better than others and total score was 15.25 in high grade, 12.97 in middle grade and 9.80 in low grade. 9) Price had a positive correlation with caffeine, appearance and taste, but a negative correlation with tannine. NT rate had a negative correlation with tannine, but a positive correlation with caffeine.