• Title/Summary/Keyword: disconnection problem

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Investigation on Design Aspects of the Constructed Wetlands for Agricultural Reservoirs Treatment in Korea (농업용 저수지 수질개선을 위한 국내 인공습지 설계 및 시공실태 조사)

  • Kim, Youngchul;Choi, Hyeseon;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.23 no.2
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    • pp.189-200
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    • 2021
  • To improve the water quality of agricultural reservoirs, constructed wetlands are applied in many places. These are technologies that establish ecosystems and important design factors include water depth distribution, inflow and outflow, water flow distribution, hydraulic residence time, water quality treatment efficiency, aspect ratio, and the distribution of open water and covered water surfaces. For high efficiency during the operation of a constructed wetland, the design needs to be optimized and this requires consideration of the different types and length of the intake dam as well as the type and connection of wetland cells. Therefore, this study was conducted to investigate and suggest factors that needs to be considered during the design and for efficient operation measures through field surveys of 23 constructed wetlands that have been established and operated in agricultural reservoirs. Results of the field investigation shows that several sites were being operated improperly due to the malfunctioning or failure of the water level sensors, sedimentation in the intake dam, and clogging of the mechanical sluice frames. In addition, it was found that as the length of the inlet channel increases, the ecological disconnection between the intake dam upstream and the wetland outlet downstream also increases and was identified as a problem. Most of the wetlands are composed of 2 to 5 cells which can result to poor hydraulic efficiency and difficulty in management if they are too large. Moreover, it was found that the flow through a small wetland can be inadequate when there are too many cells due to excessive amounts of headloss.

Evaluation of Priorities for Greening of Vacant Houses using Connectivity Modeling (연결성 모델링을 활용한 빈집 녹지화 우선순위 평가)

  • Lee, Hyun-Jung;Kim, Whee-Moon;Kim, Kyeong-Tae;Shin, Ji-Young;Park, Chang-Sug;Park, Hyun-Joo;Song, Won-Kyong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.25 no.1
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    • pp.25-38
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    • 2022
  • Urban problems are constantly occurring around the world due to rapid industrialization and population decline. In particular, as the number of vacant houses is gradually increasing as the population decreases, it is necessary to prepare countermeasures. A plan to utilize vacant houses has emerged to restore the natural environment of the urban ecosystem where forest destruction, damage to habitats of wild animals and plants, and disconnection have occurred due to large-scale development. Through connectivity analysis, it is possible to understand the overall ecosystem flow based on the movement of species and predict the effect when vacant houses are converted into green spaces. Therefore, this study analyzed the green area network to confirm the possibility of greening of vacant houses neglected in Jeonju based on circuit theory. Using Circuitscape and Least-cost path, we tried to identify the connectivity of green areas and propose an ecological axis based on the analysis. In order to apply the resistance values required for analysis based on previous studies, the 2020 subdivision land cover data were integrated into the major classification evaluation items. When the eight forests in the target site were analyzed as the standard, the overall connectivity and connectivity between forests in the area were high, so it is judged that the existing green areas can perform various functions, such as species movement and provision of habitats. Based on the results of the connectivity analysis, the importance of vacant houses was calculated and the top 20 vacant houses were identified, and it was confirmed that the higher the ranking, the more positive the degree of landscape connectivity was when converted to green areas. In addition, it was confirmed that the results of analyzing the least-cost path based on the resistance values such as connectivity analysis and the existing conceptual map showed some differences when comparing the ecological axes in the form. As a result of checking the vacant houses corresponding to the relevant axis based on the width standards of the main and sub-green areas, a total of 30 vacant houses were included in the 200m width and 6 vacant houses in the 80m width. It is judged that the conversion of vacant houses to green space can contribute to biodiversity conservation as well as connectivity between habitats of species as it is coupled with improved green space connectivity. In addition, it is expected to help solve the problem of vacant houses in the future by showing the possibility of using vacant houses.

A Study on the Characteristic and Improvement Method of Private Consignment of Social Welfare Facility(Organization) (사회복지시설(기관)의 민간위탁제도 특성 및 개선방안에 관한 연구)

  • Kong, Chang-Suk
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.6 no.3
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    • pp.109-129
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    • 2011
  • Since the introduction of local autonomy system, various specific theories and practical approaches for private commission system have been common concerns and interests of the fields practicing social welfare. In the discussion about private consignment system of social welfare facility and organization, both of private section and government have shown different opinions from various aspects such as related regulation, consignment procedure, proper period and consignment condition. According to the discussion about the consignment system of social welfare facility, the purpose of this study is as follows. The first purpose is to suggest the current status of private consignment of social welfare facility and the characteristic and issue of consignment procedure by considering domestic & overseas literatures about the characteristic of private consignment system. The second purpose is to find out the general characteristics and current statuses of consignment process and system of social welfare facilities (organizations) located in Gyeonggi-do area. The third purpose is to draw the current status and general problem of field consignment system and suggest the practical alternative plan and improvement method of private consignment system of social welfare facility in the future. The result of researching private consignment process by head and manager of social welfare facility (organization), private consignment agreement and its conclusion process and current consignment system improvement method revealed that the number of reconsigned (over 1~3 times) facilities was more than that of initially consigned facilities and senior welfare facility and general social welfare center were most frequent in private consignment organization. In addition, as an improvement method of current private consignment process, the consideration on each organization and standard was required for new consignment and reconsignment and the problem of fairness and objectiveness was indicated when deliberation committee was organized in private consignment process. Besides them, it was found that consignment period shall be adjusted on the basis of facility type and business characteristic and the problems such as worker's succession, worker's transfer and service disconnection were suggested when consignment organization was changed. For conclusion and suggestion, the study suggested the establishment of common standard about private consignment, alternative plan of private consignment process issue and improvement method of consignment period issue.

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Analysis and the Standardization Plan of the Terms Used by Seafarers on Small Vessel (소형선박 종사자 사용용어 실태 분석 및 표준화 방안)

  • Kang, Suk-Young;Ryu, Won;Bae, Chang-Won;Kim, Jong-Kwan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.7
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    • pp.867-873
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    • 2019
  • As of August 2019, there were 3,823 vessels under 30 tons that could be included in the category of small vessels; these account for 42.5 % of the 9,001 registered vessels in Korea. The problem is that many small vessel seafarers face many problems such as an board communication disconnection, difficulties in communication in maritime license interviews, or education related to maritime training using a large number of nonstandard terms, which are derived from foreign languages; this is leading to a decline the job skills of small vessel seafarers. Therefore, in this study, we closely analyzed the terminology of small vessel seafarers and proposed a standardization plan. In the terminology analysis, the preliminary terms of the maritime license interview and the high-frequency terms of the small vessel educational textbook were identified and the corresponding nonstandard terms were examined. Based on a survey, an expert meeting was held and incorrect Japanese notation, English notation, and the standard language for key terms were presented to analyze which questionnaire was most familiar. The ratio of the use of standard words is relatively high in the case of nautical terms, however, the wrong Japanese notation is used more for engine terms; the analysis results by age and tonnage also generally use the Japanese notation and the use frequency of English notation was determined to be low. Based on this, short- and long-term plans for the use of standard words by small vessel seafarers were proposed, including the production of a standard language dictionary for terms used by these seafarers, a promotion of the importance of using standard terms, active education through educational institutions, and the systematic preparation and implementation of Korean-language education for foreign sailors.