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Monitoring of a Time-series of Land Subsidence in Mexico City Using Space-based Synthetic Aperture Radar Observations (인공위성 영상레이더를 이용한 멕시코시티 시계열 지반침하 관측)

  • Ju, Jeongheon;Hong, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.37 no.6_1
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    • pp.1657-1667
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    • 2021
  • Anthropogenic activities and natural processes have been causes of land subsidence which is sudden sinking or gradual settlement of the earth's solid surface. Mexico City, the capital of Mexico, is one of the most severe land subsidence areas which are resulted from excessive groundwater extraction. Because groundwater is the primary water resource occupies almost 70% of total water usage in the city. Traditional terrestrial observations like the Global Navigation Satellite System (GNSS) or leveling survey have been preferred to measure land subsidence accurately. Although the GNSS observations have highly accurate information of the surfaces' displacement with a very high temporal resolution, it has often been limited due to its sparse spatial resolution and highly time-consuming and high cost. However, space-based synthetic aperture radar (SAR) interferometry has been widely used as a powerful tool to monitor surfaces' displacement with high spatial resolution and high accuracy from mm to cm-scale, regardless of day-or-night and weather conditions. In this paper, advanced interferometric approaches have been applied to get a time-series of land subsidence of Mexico City using four-year-long twenty ALOS PALSAR L-band observations acquired from Feb-11, 2007 to Feb-22, 2011. We utilized persistent scatterer interferometry (PSI) and small baseline subset (SBAS) techniques to suppress atmospheric artifacts and topography errors. The results show that the maximum subsidence rates of the PSI and SBAS method were -29.5 cm/year and -27.0 cm/year, respectively. In addition, we discuss the different subsidence rates where the study area is discriminated into three districts according to distinctive geotechnical characteristics. The significant subsidence rate occurred in the lacustrine sediments with higher compressibility than harder bedrock.

On the 'realization' meaning of possibility expressions - '-ul swu iss-' and its counterparts in Japanese and Chinese - (가능 표현의 실현 용법에 대하여 - '-을 수 있-' 및 일본어·중국어의 대응 표현을 중심으로 -)

  • Kang, Yeongri;Xu, Cuie;Park, Jinho
    • Cross-Cultural Studies
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    • v.50
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    • pp.313-346
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    • 2018
  • It is noted that generally speaking, the expressing of actualization or non-actualization of events is not the main role of possibility for the utilization of expressions. In spite of this fact, it is possible to see many examples in which possibility expressions represent actual events, and impossibility expressions represent a type of non-actualization in relation to events. This effect can be described as a semantic extension, by which the participant-internal possibility is extended to actualization due to participant-internal factors, and the participant-external possibility is extended to the actualization due to participant-external factors. When the related possibility expressions are used in this extended sense, they express the dynamic evaluative meaning of 'desirability' of the realized event, while it is determined that when the impossibility expressions are used in this extended sense, they are seen to express the evaluative meaning of 'regretfulness' about the non-actualization of the event. In Modern Japanese, it is noted that there are a few expressions of ability and possibility. They can be largely divided into four types of expressions, according to their origins or uses of expression, which are 'ability verbs', affixes '-れる/られる(-reru/rareru)', '-できる(-dekiru)', and '-得る(-eru)'. They can all express participant-internal possibility and participant-external non-deontic possibility. While 'ability verbs', affixes '-れる/られる' and '-できる' can express participant-external deontic possibility, '-得る' cannot. However, '-得る' is the only possible element to designate the event of a epistemic possibility. Also, the four types of expressions have the usage of conveying 'actualization/non-actualization,' as is the case of the Korean language. However in Japanese, in fact adjectives cannot be associated with 'ability verbs' or 'ability affixes.' Thus the expressions of 'regrets' should in that case depend on the use contexts, unlike the expression 'adj+-지 못하다' as noted in Korean. The ability and possibility in Modern Chinese are mainly expressed by means of the four auxiliary verbs '能($n{\acute{e}}ng$)', '会(huì)', '可以(kěyǐ)' and '可能 ($k{\check{e}}n{\acute{e}}ng$)'. '能' and '会' along with '可以' can all convey participant-internal possibility. In this way '能' and '可以' can express participant-external possibility. Only '会' and '可能' can express epistemic possibility. As for 'actualization,' among the four auxiliary verbs, only '能' can represent actualization. Also, among the negatives of the four auxiliary verbs, only '沒能' can represent non-actualization.

Canopy-Related Characteristics of Korean Soybean Cultivars (한국 콩 품종의 초형관련 형질의 특성)

  • Kim, Hong-Sig;Lee, Ku-Hwan;Song, Hang-Lin;Kim, Seong-Jin;Hur, Gun;Woo, Sun-Hee;Jong, Seung-Keun
    • Korean Journal of Breeding Science
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    • v.40 no.2
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    • pp.143-152
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    • 2008
  • This study was conducted to obtain basic information on mainstem, branch and leaf characteristics related to canopy for development of high yielding cultivar using 70 Korean soybean cultivars developed from 1913 to 2000. Variations of canopy width, branch length, and canopy width/length ratio were higher compared to other characteristics among 12 mainstem and branch characters. Variations of petiole angle, leaflet width/length ratio and compound leaf dry weight were higher than other characteristics among eight leaf characters related to plant canopy. Three classifications of soybean cultivars were used based on usage: I)soy sauce and tofu, II)bean sprout, and III)cooking with rice. Canopy width/length ratio was higher in group III, cooking with rice than group I, soy sauce and tofu, and group II, bean sprout, and there was no difference between the two, group I and group II. The total branch length/main stem height ratio was higher in group II, bean sprout and group III, cooking with rice than group I, soy sauce and tofu. Mainstem and branch characteristics related to plant canopy were classified into four groups by ratio of canopy width/length and total branch length/main stem length, respectively. Soybean cultivars with narrow canopy and high dependence of mainstem were Danweonkong, Keumkangkong, Shelby, and Shinpaldalkong. Soybean cultivars with broad canopy and high dependence of mainstem were Kanglim, Keumkangdaelip, and Jinyulkong, and a cultivar with broad canopy and high dependence of branch were Geomjeongkong 2. Leaflet length/width ratio was lowest in cooking with rice and there was no difference between soy sauce and tofu and bean sprout. Compound leaf area was largest in cooking with rice and smallest in bean sprout. Leaf petiole length was short in bean sprout and there was no difference between soy sauce and tofu and bean sprout. Leaf petiole angle was highest in cooking with rice and lowest in bean sprout. Leaf type was classified into four groups based on leaflet width/length ratio and compound leaf area, respectivly. Buseok and Taekwangkong had an oval leaflet and largest area of compound leaf. Eunhakong and Sohokong had extreme narrow leaflet and smallest area of compound leaf. Leaf petiole type was classified into three and four groups based on leaf petiole length and angle, respectively. A soybean cultivar with the shortest petiole length and smallest petiole angle was Eunhakong and cultivars with short petiole length and large petiole angle were Alchankong, Muhankong, and Pureunkong. A soybean cultivar with long petiole length and small petiole angle was Sinpaldalkong 2. Among a total of 70 Korean soybean cultivars, Eunhakong had an extreme narrow type in leaf, smallest compound leaf area, shortest petiole length, and smallest petiole angle of compound leaf.

A Study on the Characteristics of Seoul Olympic Organizing Committee's Official Documents (서울올림픽대회 조직위원회 공문서의 성격에 관한 연구)

  • Cheon, Ho-Jun
    • The Korean Journal of Archival Studies
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    • no.24
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    • pp.113-171
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    • 2010
  • The purpose of this study was to examine the characteristics of Seoul Olympic Organizing Committee's official documents. To conduct this work, the fundamental of producing archives were examined by analyzing structure and management of Seoul Olympic Organizing Committee and structure of official document production. After all, simultaneous and synthesis characteristics of Seoul Olympic Organizing Committee's official documents were presented through overall analysis of production fundamental and relationship between their management and remained archives. The result of this study are as follows. Firstly, The Organizing Committee had bicameral organizational structure and matrix organizational format consisting of functional department and project department. Indicating the institutions and development phase of decision making in the committee, most of institutions were in name only. Also, there were many problems occurred in the procedure of decision making since the president of committee exercised all of the authorities. Secondly, It was found that existing official documents of the committee were partial and caused fragment phenomenon and severe situations because of unsystematic archival management department and regulations. Moreover, as the result of investigating production procedure and management of official documents, procedure of production, distribution, preservation and abolition of them were specifically verified. Thirdly, It was verified that the official documents were abolished arbitrarily because of unsystematic archival management department and insufficient regulations. For the actual condition of management, filing or description activity which is essential measure for using and utilizing the official documents has not been conducted yet. Based on these facts, the characteristics of Seoul Olympic Organizing Committee's official documents can be referred as follows. The official archives of the committee have multiplicity of the origin and severe fragment phenomenon damaging the origin and the elementary substance of the archives. Also, the format of existing archives was unbalance. Besides, there was not enough related research since they were in adverse situation to utilize them as the archives which are not assessed or not arranged. Thus, it was hard to grasp the utility value at present and future, and was also limited for usage object.

Comparison of Thermal Insulation of Multi-Layer Thermal Screens for Greenhouse: Results of Hot-Box Test (온실용 다겹보온자재의 보온성 비교 -Hot box 시험 결과를 중심으로-)

  • Yun, Sung-Wook;Lee, Si-Young;Kang, Dong-Hyeon;Son, Jinkwan;Park, Min-Jung;Kim, Hee-Tae;Choi, Duk-Kyu
    • Journal of Bio-Environment Control
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    • v.28 no.3
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    • pp.255-264
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    • 2019
  • In this study, we conducted the hot box tests to compare the changes in thermal insulation for the four types of multi-layer thermal screens by the used period after collecting them from the greenhouses in the field when they were replaced at the end of their usage. The main materials for these four types of multi-layer thermal screens were matt georgette, non-woven fabrics, polyethylene (PE) foam, chemical cotton, etc. These materials were differently combined for each multi-layer thermal screen. We built specimens ($70{\times}70cm$) for each of these multi-layer thermal screens and measured the temperature descending rate, heat transmission coefficient, and thermal resistance for each specimen through the hot box tests. With regard to the material combinations of multi-layer thermal screens, thermal insulation can be increased by applying a multi-layered PE foam. However, it is considered that the multi-layered PE foam significantly less contributes to heat-retaining than chemical wool that forms an air-insulating layer inside multi-layer thermal screens. For the suitable heat-retaining performance of multi-layer thermal screens, basically, materials with the function of forming an air-insulating layer such as chemical cotton should be contained in multi-layer thermal screens. The temperature descending rate, heat transmission coefficient, and thermal resistance of multi-layer thermal screens were appropriately measured through the hot box tests designed in this study. However, in this study, we took into consideration only the four kinds of multi-layer thermal screens due to difficulties in collecting used multi-layer thermal screens. This is the results obtained with relatively few examples and it is the limit of this study. In the future, more cases should be investigated and supplemented through related research.

A re-appraisal of scoring items in state assessment of NATM tunnel considering influencing factors causing longitudinal cracks (종방향균열 영향인자 분석을 통한 NATM터널 정밀안전진단 상태평가 항목의 재검토)

  • Choo, Jin-Ho;Yoo, Chang-Kyoon;Oh, Young-Chul;Lee, In-Mo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.4
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    • pp.479-499
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    • 2019
  • State assessment of an operational tunnel is usually done by performing visual inspection and durability tests by following the detailed guideline for safety inspection (SI) and/ or precision inspection for safety and diagnosis (PISD). In this study, 12 NATM tunnels, which have been operational for more than 10 years, were inspected to figure out the cause of longitudinal cracks for the purpose of modifying the scoring items in the state assessment NATM tunnel related to the longitudinal crack and the thickness of concrete lining. All investigated tunnels were classified into four groups depending on the shape and usage of each tunnel. The causes of longitudinal crack occurrence were analyzed by investigating the correlations between the longitudinal crack and the following four factors: the patterns of ground excavation; construction state of primary support system; characteristics of material properties of the concrete lining; and thickness of lining which was obtained by Ground Penetration Radar (GPR) tests. It was found that influencing factors causing longitudinal cracks in the lining were closely related with the construction condition of the primary support system, i.e. shotcrete, rockbolt, and steel-rib; crack occurrences were not much affected by the excavation patterns. As for the properties of concrete lining materials, occurrence of the longitudinal crack was mostly affected by the following three items: w/c ratio; contents of cement; and strength of lining. When estimating the lining thickness of the concrete lining by GPR tests and taking thickness effect into account in the statement assessment, it was concluded that increase of the index score by an average of 0.03 (ranging from 0.01 up to 0.071) is needed; a more realistic way of state assessment should be proposed in which the increased index score caused by lack of lining thickness should be taken into account.

Comparison of Productivity and Feed Value at Different Harvest Stages and Seeding Methods of Bermudagrass and Bahiagrass Cultivars (Bermudagrass와 Bahiagrass의 품종별 수확시기 및 파종방법에 따른 생산성 및 사료가치 비교)

  • Lee, Wang Shik;Im, Suk Ju;Kim, Bum Jun;Kim, Young Jin;Kim, Dong Hoon;Hwang, Kyung Jun;Kim, Si Hyun;Woo, Jae Hoon;Park, Nam Geon
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.38 no.4
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    • pp.310-319
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    • 2018
  • The southern type grasses announced for the test were the Bermudagrass cultivars (Giant, Cheyenne, Mohawk, Panchero Frio, Common and Tifton 85) and the Bahiagrass cultivars (TifQuik, Tifton 9), and the changes in the productivity and nutrient content were surveyed in Jeju area (450m altitude). The different cultivars were sowed by broadcasting or drill seeding method, and Tifton 85 was transplanted from sprigs. The fresh and dry matter yield showed varying significant differences for different cultivars (p<0.05). The fresh yields of Tifton 85, TifQuik and Tifton 9 were excellent, compared to the other cultivars, and for the dry matter yield, Tifton 85 and Tifton 9 were excellent when compared to the other cultivars. Crude protein content showed significant differences among different cultivars (p<0.05). Cheyenne, Mohawk, Panchero Frio, and Common showed differences in the crude protein content by sowing method and harvest time (p<0.05). The different cultivars showed differences in the crude fiber content (p<0.05), and Tifton 9 registered significantly high content and Mohawk and Tifton 85 showed significant crude fiber content by harvest time (p<0.05). According to these results, the southern type grass cultivars showed big differences in the regenerative capacity against damage from frost, productivity, and nutrient content, so they need to be chosen according to the purposes, and to increase their usage, their evaluation needs to be conducted at various altitudes.

Experiments on Flow Characteristics of Asphalt Seal Composite Waterproofing Method for Underground Concrete Structure Exterior Wall Waterproofing (지하 콘크리트 구조물 외벽 방수용 아스팔트 씰재 복합방수 공법의 흘러내림 특성에 관한 실험)

  • Ko, Sang-Ung;Kim, Kyoung-Hoon;Kim, Young-Sam;Shin, Hong-Chul;Kim, Jin-Man
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.4
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    • pp.297-303
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    • 2018
  • With the changing trend of the building construction to high rising and large scaling, the underground structure has been increased, and its usage also increased and variety. Hence, to protect the underground structure against underground water, various water proofing methods has been developed. Among the many water proofing methods, the combined water proofing method using both asphalt seal and sheet has been widely used to secure the sufficient performance and decrease the construction failure. However, during the summer period of extremely high temperature conditions, the asphalt sealing materials were separated and leaked into the structure. Therefore, the aim of the research is to provide the quality standard of asphalt sealing material based on the various temperature changes depending on seasons. According to the experimental results, the temperature of the sealing materials applied on the slab was increased up to $54^{\circ}C$ which was $3^{\circ}C$ higher than the structure temperature of $51^{\circ}C$. Based on the melting test for asphalt sealing materials applied on the outside wall of the structure, in the case of water-dispersing typed materials showed significant melting down due to its slow evaporation and low viscosity. Furthermore, from the accelerated test conducted indoor conditions, a solvent-type and water-dispersing typed materials showed significant melting down due to their low viscosity and melting point in ambient conditions. Based on these results, viscosity and melting point are found as the important factors on asphalt sealing materials' quality, and it is necessary to designate the quantitative level of the viscosity and melting point for quality control.

A Study on the Design of the Grid-Cell Assessment System for the Optimal Location of Offshore Wind Farms (해상풍력발전단지의 최적 위치 선정을 위한 Grid-cell 평가 시스템 개념 설계)

  • Lee, Bo-Kyeong;Cho, Ik-Soon;Kim, Dae-Hae
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.7
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    • pp.848-857
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    • 2018
  • Recently, around the world, active development of new renewable energy sources including solar power, waves, and fuel cells, etc. has taken place. Particularly, floating offshore wind farms have been developed for saving costs through large scale production, using high-quality wind power and minimizing noise damage in the ocean area. The development of floating wind farms requires an evaluation of the Maritime Safety Audit Scheme under the Maritime Safety Act in Korea. Floating wind farms shall be assessed by applying the line and area concept for systematic development, management and utilization of specified sea water. The development of appropriate evaluation methods and standards is also required. In this study, proper standards for marine traffic surveys and assessments were established and a systemic treatment was studied for assessing marine spatial area. First, a marine traffic data collector using AIS or radar was designed to conduct marine traffic surveys. In addition, assessment methods were proposed such as historical tracks, traffic density and marine traffic pattern analysis applying the line and area concept. Marine traffic density can be evaluated by spatial and temporal means, with an adjusted grid-cell scale. Marine traffic pattern analysis was proposed for assessing ship movement patterns for transit or work in sea areas. Finally, conceptual design of a Marine Traffic and Safety Assessment Solution (MaTSAS) was competed that can be analyzed automatically to collect and assess the marine traffic data. It could be possible to minimize inaccurate estimation due to human errors such as data omission or misprints through automated and systematic collection, analysis and retrieval of marine traffic data. This study could provides reliable assessment results, reflecting the line and area concept, according to sea area usage.

Structuration of Space Change due to Planning and Leisure Activities in Hangang River Park - Focused on the Hangang River Park in Yeouido from the 1970s to the 2000s - (여가 활동 공간으로서 여의도 한강공원 공간변화의 구조화 - 1970년대부터 2000년대까지 여의도 한강공원의 여가 활동과 계획을 중심으로 -)

  • Cho, Han-Sol
    • Journal of the Korean Institute of Landscape Architecture
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    • v.47 no.2
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    • pp.13-27
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    • 2019
  • This study shows the changes in the space created by the planning and leisure activities of Hangang River Park, focusing on the Yeouido portion of the Hangang River Park, which has the most users and the greatest degree of planning. The relationship between planning, behavior, and space changes are explained based on Giddens's Structural Theory. As research material, Hangang River Park plans and satellite photos were interpreted and newspaper articles were used to identifying the space changes and their causes, and a model of the space changes was derived through the application of the theory. The flow of space change in the Yeouido portion of the Hangang River Park due to planning and leisure activities is as follows. In the 1970s, the first sports spaces are made due to need from residents near the riverside, but huge plans for the utilization of the entire space were not realized. In the 1980s, leisure spaces were planned and developed through a comprehensive plan. Various sports spaces were built, but the environment of the spaces became a slum. In the 1990s, various leisure activities were revitalized due to the revision of the legal system, regulations on the usage of space, and space maintenance, and from the late 1990s, ecological issues arose along the Hangang River. In the 2000s, there was an overall space improvement project directed by two comprehensive plans, and cultural and ecological issues appeared in the Hangang River Park plans. However, actual leisure spaces were developed along with the promotion of large-scale activities. Regarding the structuration theory, elements of interaction, modality, and structure are the aspects of space changes in the Yeouido portion Hangang River Park. As the flow of the space change, the proportions of the comprehensive plan and the individual plans were similar. The comprehensive plan was influenced by the change of public businesses and the proliferation of large-scale activities. Individual plans were influenced by the user's activities and opinions. However, both plans were influenced by the users and suppliers. The leisure space of the Hangang River Park can be viewed as a social space, in terms of the structuring as a theory due to the user repeatedly changing the use of the space. The purpos of this study is to investigate the changes in the Hangang River Park space through planning and leisure activities. Through this study, we can understand the characteristics of the Hangang River Park in planning the leisure activity space.