• Title/Summary/Keyword: Pitching system

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A Dynamic Analysis of PSC Box Bridge Varying Span Lengths for Increased Speeds of KTX (고속철 속도변화에 대한 PSC박스 교량의 경간길이 별 동적해석)

  • Oh, Soon Taek;Lee, Dong Jun;Shim, Young Woo;Yun, Jun Kwan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.4
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    • pp.204-211
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    • 2011
  • A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of bridge during the passage of high speed railway vehicles. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyse accurately and evaluate with in-depth parametric studies for dynamic responses of various bridge span lengths running KTX railway locomotive up to increasing maximum speed(450km/h). Three dimensional frame element is used to model the simply supported pre-stressed concrete (PSC) box bridges for four span lengths(40~25m). Track irregularity employed as a stationary random process from the given spectral density functions and irregularities of both sides of the track are assumed to have high correlation. The high-speed railway vehicle (KTX) is used as 38-degree of freedom system. Three displacements (Vertical, lateral, and longitudinal) as well as three rotational components (Pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic amplification factors are evaluated by the developed procedure under various traveling conditions, such as track irregularity camber, train speed and ballast. The dynamic analysis such as Newmark-${\beta}$ and Runge-Kutta methods which are able to analyse considering the dynamic impact factors are compared and contrasted.

DEVELOPMENT OF THREE-DIMENSIONAL DYNAMIC ANALYSIS MODEL HIGH SPEED TRAIN-BRIDGE INTERACTION (철도 차량 - 교량 상호작용에 의한 3차원 동적 해석 모델 개발)

  • Dinh, Van Nguyen;Kim, Ki Du;Shim, Jae Soo;Choi, Eun Soo;Songsak, Suthasupradit
    • Journal of Korean Society of Steel Construction
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    • v.20 no.1
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    • pp.151-163
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    • 2008
  • A formulation of three-dimensional model of articulated train-b ridge dynamic interaction has been made for the Korean eXpress Train (KTX). Semi-periodic profiles of rail irregularities consisting of elevation, alignment, cross and gauge irregularities have also been proposed using FRA maximum tolerable rail deviations. The effects of rail joints and sleeper step were also included. The resulting system matrices of train and bridge are very spare, and thus, are stored in one-dimensional arrays, yielding a time-efficient solution. A numerical algorithm for computing bridge-train response including an iterative scheme is also formulated. A program simulating train-bridge interaction and solving this problem using the new algorithm is implemented as new modules for the f inite element analysis software named XFINAS. Computed results using the new program are then checked by that of the validated 2-D bridge-train interaction model. This new 3D analysis provides more detailed train responses such as swaying, bouncing, rolling, pitching and yawing accelerations, which are useful inevaluating passenger riding comfort. Train operation safety and derailment could also be directly investigated by relative wheel displacements computed from this program.

A Study for a Way to Invigorate Domestic Documentary Ecosystem: Focusing on the Growth of Independent Documentaries and the Case of POV (다큐멘터리 생태계의 활성화 방안 -독립 다큐멘터리의 성장과 미국 POV 사례를 중심으로)

  • Lee, EunKyung;Im, SoYun
    • The Journal of the Korea Contents Association
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    • v.19 no.6
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    • pp.168-178
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    • 2019
  • This study takes a close look at the recent success of independent documentaries to find its implications and a way to invigorate Korean documentary ecosystems. To this aim, this study performed in-depth interviews with independent documentary film makers and television documentary directors. Also, it analyzed the case of POV (Point Of View), which is television's longest-running showcase for independent documentary films in the USA. The results display that independent documentaries convey competitive edge of contents and expansion of distribution and funding through film industry systems, based on the producer systems, global distribution networks of overseas pitching and film festivals, marketing and audience strategy of film industry. Although this shows its molding of documentary industry ecosystems, there are great needs for various platforms other than film industrial outlet in order to make an advancement of the ecosystems under the digital environment. POV works on the basis of 'open sourcing' form when collaborating with independent film makers. Independent documentaries picked up by POV are aired on PBS, streamed via its online service, and distributed through community screenings; this three-outlet strategy makes POV a unique platform and has a relevance and feasibility to apply for Korean documentary ecosystems. Therefore, this study suggests to create a platform adopting POV system hoping that more studies and efforts would come for various and novel platform building so to make more advanced and invigorated ecosystems of Korean documentary.

Comparative Analysis of Technical System by Six Organic Rice Cultivation Type in the Southern Provinces (남부지방 벼 유기농법 유형별 투입기술체계 비교분석)

  • Ahn, In;Park, Joo-Seob;Kim, Sam-Hyun;Maeng, Woon-Young;Lee, In-Eae
    • Korean Journal of Organic Agriculture
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    • v.20 no.4
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    • pp.535-542
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    • 2012
  • This study was carried out from 2011 to 2012 in order to analyze the cultivation technology system by six organic rice cultivation types in the southern provinces for the purpose of utilizing organic rice farming guidelines. This surveys were conducted by site visit on 8 counties and 115 farms in southern area. Cultivation technology system by six organic rice cultivation types were cultivated by the principle of minimum input or non-input. cropping systems, a mixture of barley and rice, or rice green manure crops were grown. Cultivars were mixture of the local cultivars and Japanese varieties. Soil were managed by a self-manufactured compost, indigenous microorganisms and barley straw without any fertilization. Pest control was mainly practied by purchased eco-friendly organic materials or herbal medication residue and indigenous microbial self-manufactured. Weed was controled by snails and barley straw. In addition, considering the restore of a longtail pitching shrimp and grasshoppers, the fuction of environmental ecology of six organic rice cultivation type proved to be excellent all. Meanwhile, the productivity of the organic farming per 10a were the order of Life and environment > Natural circulation > Stevia > Ji jang > Art and nature > Taepyoung of Farming Methods, but the farmers received prices showed the opposite tendency. Simple profitablity did not show a big difference. But, the productivity of all type of the organic farming were lower then the conventional farming. Finally, If we want to conduct safety and easy farming, we can suggest stevia farming, Natural circulation farming and life and environmental farming out of 6 organic rice cultivation types.

The Impact of Entrepreneurship Education on Entrepreneurial Intentions and Entrepreneurial Behavior of Continuing Education Enrolled Students in University: Focusing on the Mediating Effect of Self-efficacy (창업교육이 성인학습자의 창업의지와 창업행동에 미치는 영향: 자기효능감 매개효과를 중심으로)

  • Yu, So Young;Yang, Young Seok;Kim, Myung Seuk
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.1
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    • pp.107-124
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    • 2023
  • As getting in 4th Industrial Revolution Times, Continuing Education Enrolled Students(CEES) trying to find loophole for jepordized current life and need job transfer have surged their interest significantly on starting new business to bring up their post career after retirement through self-improvement. Government and university have actively initiated diverse policies of promoting startup for CEES in kicking off entrepreneurship courses and programs. However, relevant main policy, 'The 2nd University Startup Education Five-Year Plan (draft)' have too chiefly focused on theoretical start-up education rather than practical courses, causing the problem of inappropriate support for implementing real startup and business (Ministry of Education, 2018). This study is brought to empirically investigate the effect of self-efficacy as perspective of the impact of entrepreneurship education on entrepreneurial intention and behavior to come up with problem of poor entrepreneurial environment and entrepreneurship education to CEES. As to empirical research, this paper deliver on-line survey to CEES from September to October 2022, collect 207 effective feedbacks, In order to verify the reliability of the scale, the Cronbach's Alpha Coefficient (Cronbach's α) was calculated, analyzed, and measured. For hypothesis test, this paper utilize the multiple regression analysis statistical analysis method and use the SPSS 22.0 statistical processing program. Empirical results show, first, it was found that self-efficacy had a significant effect on start-up education. Second, start-up education had a significant effect on the intention to start a business of adult learners. Third, start-up education had a significant effect on the start-up behavior of adult learners. Fourth, self-efficacy had a significant effect on the intention of adult learners to start a business. Fifth, self-efficacy had a significant effect on the start-up behavior of adult learners. Sixth, self-efficacy had a mediating effect in the relationship between entrepreneurship education and adult learners' intention to start a business. Seventh, self-efficacy had a complete mediating effect in the relationship between start-up education and adult learners' start-up behavior. This paper is brought three significant implications. First, main consideration developing entrepreneurship education tools for CEES need to falls on defining potential needs of CEES as segmenting as to coming up with diversity of CEES's characteristics such as gender, age, experience, education, and occupation. Second, as to design specific entrepreneurship education program, both practical training program of utilizing CEES's career field experience benchmarking best practice startup and venture cases from domestic and global, and professional startup program of CEES initiating directly startup from ideation to develop business plan with pitching and discussing. Third, entrepreneurship education for CEES should be designed to incubate self-efficacy to enhance entrepreneurial intention of implementing entrepreneurial behavior as a real, eventually leading solid support system of self-improvement for CEES' Retirement life planning.

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