• Title/Summary/Keyword: realistic operation conditions

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Estimation of Leg Collision Strength for Large Wind Turbine Installation Vessel (WTIV) (대형 해상풍력발전기 설치 선박(WTIV) Leg구조의 충돌 강도평가)

  • Park, Joo-Shin;Ma, Kuk-Yeol;Seo, Jung-Kwan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.26 no.5
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    • pp.551-560
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    • 2020
  • Recently, the offshore wind power generator market is expected to grow significantly because of increased energy demand, reduced dependence on fossil fuel-based power generation, and environmental regulations. Consequently, wind power generation is increasing worldwide, and several attempts have been made to utilize offshore wind power. Norway's Petroleum Safety Authority (PSA) requires a leg-structure design with a collision energy of 35 MJ owing to the event of a collision under operation conditions. In this study, the results of the numerical analysis of a wind turbine installation vessel subjected to ship collision were set such that the maximum collision energy that the leg could sustain was calculated and compared with the PSA requirements. The current leg design plan does not satisfy the required value of 35 MJ, and it is necessary to increase the section modulus by more than 200 % to satisfy the regulations, which is unfeasible in realistic leg design. Therefore, a collision energy standard based on a reasonable collision scenario should be established.

The Changes and Present Status of Education in Clothing Departments at Vocational High Schools (전문계 고등학교 의상과 교육과정에서의 교육목표 및 내용에 관한 연구)

  • Yoo, Hye-Ja;Chunhg, Mee-Kyung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.34 no.2
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    • pp.371-384
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    • 2010
  • This research investigates the historical changes of the educational system for the clothing departments at vocational high schools. According to the growth of the fashion industry, employment potential in the clothing departments of the vocational high schools, numerical changes in the educational statistics, and curriculums were investigated by papers, reports, and statistic data. The statistic data were derived from the 'Center Educational Statistics and Information', 'School Information' (Hak-gyo Alimi), 'Korean Statistical Information Services' and internet home pages of vocational high schools. Technical service workers that graduate from clothing departments and vocational high schools have limited competitiveness in a thriving fashion industry field. Highly developed fashion industries require more professional workers in fashion design, fashion marketing, and fashion materials. Compared to 1994, when 35 classes were conducted in 5 vocational high schools, 69 classes are now conducted at 15 schools. They have over 2,000 students and produce over 600 graduates. However, 222 credits of the $1^{st}$ curriculum in 1958 went down to 82 credits in the 2007 revised curriculum to complete the credits of clothing departments. The 15 courses of the 1st curriculum fell to 5 courses in the 2007 revised curriculum on the number of major subjects. It is a fundamental problem that major courses in clothing education have been excessively reduced despite the demand for of highly specialized workers in the fashion industry. In the view of operating conditions of those schools, there were several problems such as the wide gaps in the curriculum, limited equipment, the supply of teachers, and counseling on the choice of college or a career. In conclusion, the following measures are required: 1) the increase of complement credits in major subjects and renovation of curriculum, 2) national substantial support to change the social circumstance concerning vocational education and occupational consciousness, 3) operation of credit approving systems in universities and colleges for students that have completed the same courses at vocational high schools, 4) designing realistic programs for vocational education and cooperation systems with corporate enterprises.

Strength degradation of a natural thin-bedded rock mass subjected to water immersion and its impact on tunnel stability

  • Zhang, Yuting;Ding, Xiuli;Huang, Shuling;Wu, Yongjin;He, Jun
    • Geomechanics and Engineering
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    • v.21 no.1
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    • pp.63-71
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    • 2020
  • Strength anisotropy is a typical feature of thin-bedded rock masses and their strength will be degraded subjected to water immersion effect. Such effect is crucial for the operation of hydropower plant because the impoundment lifts the water level of upstream reservoir and causes the rock mass of nearby slopes saturated. So far, researches regarding mechanical property of natural thin-bedded rock masses and their strength variation under water immersion based on field test method are rarely reported. This paper focuses on a thin-bedded stratified rock mass and carries out field test to investigate the mechanical property and strength variation characteristics. The field test is highlighted by samples which have a large shear dimension of 0.5 m*0.5 m, representing a more realistic in-situ situation than small size specimen. The test results confirm the anisotropic nature of the concerned rock mass, whose shear strength of host rocks is significantly larger than that of bedding planes. Further, the comparison of shear strength parameters of the thin-bedded rock mass under natural and saturated conditions show that for both host rocks and bedding planes, the decreasing extent of cohesion values are larger than friction values. The quantitative results are then adopted to analyze the influence of reservoir impoundment of a hydropower plant on the surrounding rock mass stability of diversion tunnels which are located in the nearby slope bank. It is evaluated that after reservoir impoundment, the strength degradation induced incremental deformations of surrounding rock mass of diversion tunnels are small and the stresses in lining structure are acceptable. It is therefore concluded that the influences of impoundment are small and the stability of diversion tunnels can be still achieved. The finings regarding field test method and its results, as well as the numerical evaluation conclusions are hoped to provide references for rock projects with similar concerns.

Some Issues on China General Aviation Legislation (中國通用航空立法若干問題研究)

  • Shuang, Luan
    • The Korean Journal of Air & Space Law and Policy
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    • v.31 no.2
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    • pp.99-143
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    • 2016
  • General aviation and air transport are two wings of the civil aviation industry. Chinese air transport is developing rapidly, and has become the world second air transport system only second to US since 2005. However, Chinese civil aviation is far behind the world average level, and cannot meet requirements of economic construction and social development. The transition and structural adjustment of Chinese economy provide the general aviation with a unprecedented broad market. The prospect of general aviation is promising and anticipated. The development of general aviation industry needs the legislative supports, and the current legislative conditions of Chinese general aviation are undoubtedly far behind the realistic requirements. Accelerating the legislation in Chinese general aviation industry requires scientific legislation concept. First, Legislation must promote development of general aviation industry. The general aviation will serves as a Chinese emerging industry that boosts domestic demand, promotes employment and expedite domestic economic development. We should, based on both the concept of promoting the industrial development of general aviation and national industrial planning, enact and rectify relative laws and regulations. And we should also straighten out the relationship between aviation security and industrial development and promote the revolution of low-altitude airspace management in an all-round way, in order to improve the utilization rate of airspace resources, classify and establish airspace, simplify examination and approval procedure and intensify operation management. In addition, what we should do is to expedite the infrastructure layout construction, guide the differentiated but coordinated development of general aviation industries in various areas, establish a united supervision mechanism of general aviation, redistrict the responsibilities of Chinese Air Control Agency and set up legislation, law enforcement and judicial systems with clarified institutions, clear positioning and classified responsibilities, so as to usher in a new era of the legislative management of Chinese general aviation industry. Second, shift the focus from regulations to both regulations and services. Considering the particularity of the general aviation, we should use American practices for reference and take into account both regulation and service functions when enacting general aviation laws. For example, we should reduce administrative licensing and market supervision, and adopt "criteria" and "approval" management systems for non-commercial and commercial aviation. Furthermore, pay attention to social benefits. Complete social rescuing mechanism through legislation. It should be clarified in legislation that general aviation operators should take the responsibilities of, and ensure to realize social benefits of environmental protection and ecological balance .Finally, rise in line with international standards. Modify Chinese regulations which is inconsistent with international ones to remove barriers to international cooperation. Specify basic legislative principles. One is the principle of coordination. Realize coordination between the civil aviation and general aviation, between military aviation and civil aviation, and among departments. Two is the principle of pertinence. The general aviation has its own rules and specialties, needing to be standardized using specialized laws and regulations. Three is the principle of efficiency. To realize time and space values of general aviation, we should complete rules in aerospace openness, general aviation airport construction, general aviation operations, and regulation enforcement. Four is the principle of security. Balance the maximum use of resources of Chinese airspace and the according potential threats to Chinese national interests and social security, and establish a complete insurance system which functions as security defense and indemnificatory measure. Establish a unified legal system. Currently, the system of Chinese general aviation laws consists of national legislation, administrative laws and regulations and civil aviation regulations (CAR). Some problems exist in three components of the system, including too general content, unclear guarantee measures, incomplete implementation details, and lacking corresponding pertinence and flexibility required by general aviation regulations, stringency of operation management and standards, and uniformity of standards. A law and regulation system, centered on laws and consisting of administrative laws regulations, industrial regulations, implementation details, industrial policies and local laws and regulations, should be established. It is suggested to modify the Civil Aviation Law to make general aviation laws complete, enact the Regulations of General Aviation Development, and accelerate the establishment, modification and abolition of Chinese general aviation laws to intensify the coordination and uniformity of regulations.

A Plan to Activate the Archive of Maeul Communities (마을공동체 아카이브 활성화 방안)

  • Sohn, Dong-you;Lee, Kyoung-juhn
    • The Korean Journal of Archival Studies
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    • no.35
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    • pp.161-206
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    • 2013
  • 'Maeul' is a concept connoting a community. As a place where ordinary people's lives are planned and realized, Maeul is the foundation of their daily lives as well as a place where they work, rest and enjoy pastime activities. In Korea, however, most Maeul communities are dismantled while going though the modern period representing colonization and developmental dictatorship. Growth-oriented industrialization and urbanization turned into such adverse effects as individualization, a sense of loss and a sense of alienation. Recently, through innovations from below, Maeuls are restored, and through Maeul communities restored this way, every Maeul and many researchers carry out activities to build a healthy civil society. This study was conducted on such a background. For a healthy restoration of Maeul communities and a sustainable operation of those communities, it is necessary to establish archives where record the trace of Maeul members' daily lives and relations between those members. The archive of Maeul communities is a place that contains each Maeul's local characteristics as well as human relations as well. It is because this place can be space where Maeul members can record their history, communicate with each other and make a better future. The archive of Maeul communities can be made into various different models, which can be operated by reflecting the identity of a community such as main agents and characteristics, objectives and orientation of objects recorded. Rather than when Maeul communities exist as individuals, they can display more important functions and better effect when they form a network. Therefore, it is needed to provide various and creative methodologies different from the existing government-led record management. Not only on the form of archives, but also all over their functions, such as collection, arrangement, classification, evaluation, management and utilization, Maeul and Maeul residents' norms, orientation and realistic conditions should be thoroughly reflected. Starting from a chance to look back at individuals' lives, the archive of Maeul communities will be a new chapter to restore and build a healthy community in our society and overcome social contradictions from below. Moreover, the archive of Maeul communities has a great significance that it will broaden its prospect creatively with a new paradigm, not only mechanically turning the existing public sector-centered record management into a non-governmental sector.