• Title/Summary/Keyword: Start-up Difficulties

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Optimization of Long-term Generator Maintenance Scheduling considering Network Congestion and Equivalent Operating Hours (송전제약과 등가운전시간을 고려한 장기 예방정비계획 최적화에 관한 연구)

  • Shin, Hansol;Kim, Hyoungtae;Lee, Sungwoo;Kim, Wook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.2
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    • pp.305-314
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    • 2017
  • Most of the existing researches on systemwide optimization of generator maintenance scheduling do not consider the equivalent operating hours(EOHs) mainly due to the difficulties of calculating the EOHs of the CCGTs in the large scale system. In order to estimate the EOHs not only the operating hours but also the number of start-up/shutdown during the planning period should be estimated, which requires the mathematical model to incorporate the economic dispatch model and unit commitment model. The model is inherently modelled as a large scale mixed-integer nonlinear programming problem and the computation time increases exponentially and intractable as the system size grows. To make the problem tractable, this paper proposes an EOH calculation based on demand grouping by K-means clustering algorithm. Network congestion is also considered in order to improve the accuracy of EOH calculation. This proposed method is applied to the actual Korean electricity market and compared to other existing methods.

The the Effect on External Financing of Ownership Type in Case of Early-Stage Firms (창업초기기업의 외부자금조달에 대한 기업소유구조 간 비교연구)

  • Kang, Won
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.10 no.6
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    • pp.47-57
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    • 2015
  • This study examines whether successful stand-alone firms have more difficulties than the successful firms affiliated to business groups in external financing. The easiness of external financing is measured by investment-cashflow multiple. Controlling the effects on the multiple of the past business performances and the expectation of future business performances, we investigate how the ownership type affects the multiple. The empirical results show that, when cashflows are positive, the stand-alone firms exhibit higher investment-cashflow mupltiples. When cashflows are negative, however, the opposite is true, even though the statistical significance of the result is rather low. These results do not support the general idea that stand-alone firms must have more disadvantage than subsidiary firms in raising funds from outside. If member firms of business groups have no big trouble financing externally, then the above results imply that stand-alone firms do not either identify external financing as a major difficulty in running business. Thus, if the government seeks to formulate the selective policies supporting only the promising start-ups, instead of the general policies benefiting random start-ups, then the start-up financing policy should have a lower priority.

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The Lived Experience of Mothers about Rearing of School Children With Cerebral palsy (뇌성마비 취학아동 어머니의 양육체험)

  • Baek Kyoung-Seon
    • Child Health Nursing Research
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    • v.7 no.4
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    • pp.434-450
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    • 2001
  • This study is designed to understand the meaning and nature of raising children with cerebral palsy. It researches the experience of mothers of schoolchildren with cerebral palsy by the research method of hermeneutic phenomenology. The study was conducted from November 10, 1999 to December 20, 2000. When children with cerebral palsy usually show symptoms in the early stage of cerebral palsy, mothers do not take children to a doctor for diagnosis. And, most of mothers have a difficult time to accept the reality; they usually respond to the initial diagnosis with shock, reproach, and deny. When mothers start recognizing the reality, they consider that their children have cerebral palsy due to the their mismanagement during pregnancy, delivery, nursing, and initial treatment. They shelter their children from view and feel guilty that they cannot afford to try folk remedies for their children. As time passes, mothers face conflicts between families in diverse ways. Families put the blame on genetic effects. Mothers-in-law give their daughters-in-law a hard time, husbands shift the responsibility of raising children onto their wives, and trouble arises between families-in-law and mothers native families. When children grow up, it is physically difficult for mothers to take care their children. In addition, they suffer from all the troubles in family due to childrens handicap. Mothers try the diverse methods of bringing up children. However, they start getting tired of raising children as they experience failures and financial difficulties. Mothers feel collapsed recalling the ways of raising children. They feel anxiety, miserable, lonely, and worrying when they think how children would attend school, make friends, and live in the future. In this stage, mothers do their best to raise their children with hope. They tend to compare their children with others without handicap and spend money and time in attempting all the treatments. When mothers and children join the society at school, they find that the society does not understand disabled people, teachers show inconsiderate attitude, friends avoid them, and children hardly follow classes. Such experiences make mothers feel angry and frustrated. However, when children adapt to school, mothers see the possibility that children could accomplish schoolwork. They appreciate teachers help and others consideration. Mothers place appropriate expectations on their children and help them to prepare for the future. I would make following suggestions based on the results. 1. As a primary basic course of rehabilitation nursing intervention, solution-centered nursing intervention system should be developed. The intervention needs to be based on the understanding of mothers, who raise children with cerebral palsy, through in-depth interview. 2. Advance researches on the development of individual nursing intervention should be conducted. Individual nursing intervention needs to prevent and release actual pain focusing on mothers raising children with cerebral palsy. 3. Integrated curriculum that help children with cerebral palsy lead a normal school life with ordinary children should be developed. 4. Basic research on using of facilities and effective application of service volunteer to help children with cerebral palsy in school needs to be conducted.

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A Studies on the Characteristics of Korean Government Policies for Venture Business During 2002-2012 (2002-2012년의 한국 벤처창업정책의 특징 연구)

  • Ha, Kyu-Soo;Hong, Kil-Pyo;Lee, Choonwoo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.12 no.1
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    • pp.15-24
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    • 2017
  • This research is focused on how the venture-startup policies of South Korea has changed for the last ten years and then scope on its outcomes, limits and suggestions. Several policies for venture-startup has begun when "Small Business Startup Support Law" was developed in 1986. Government's support policies for venture and startup and development of venture had made a turning point in 1997 "Act on Special Measures for the Promotion of Venture Business" and venture companies has achieved remarkable growth with Information Technologies(IT). However, with the global IT bubble and the enrichment of venture companies, a number of venture companies experienced considerable difficulties due to multiple thresholds. There were a lot of efforts to revitalize venture-startup ecosystem such as fostering innovative SMEs and one-person creative enterprise support policy. From 2002 to 2004, Korean Government focused on preventing moral hazards of Korean Venture Business. From 2005 to 2006, It focused on fostering the role of venture capitals, and From 2007 to 2012, Single start-up business has been fostered by government policies. Generally speaking, it can be said that venture-startup policy was emphasized on building the hardware infrastructure of venture-startup and supporting with the funds.

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The Construction Work Completion of the Fuel Test Loop (핵연료 노내조사시험설비 설치공사 완료)

  • Park, Kook-Nam;Lee, Chung-Young;Chi, Dae-Young;Park, Su-Ki;Shim, Bong-Sik;Ahn, Sung-Ho;Kim, Hark-Rho;Lee, Jong-Min
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.291-295
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    • 2007
  • FTL(Fuel Test Loop) is a facility that confirms performance of nuclear fuel at a similar irradiation condition with that of nuclear power plant. FTL consists of In-Pile Test Section (IPS) and Out-Pile System (OPS). FTL construction work began on August, 2006 and ended on March, 2007. During Construction, ensuring the worker's safety was the top priority and installation of the FTL without hampering the integrity of the HANARO was the next one. Task Force Team was organized to do a construction systematically and the communication between members of the task force team was done through the CoP(community of Practice) notice board provided by the Institute. The installation works were done successfully overcoming the difficulties such as on the limited space, on the radiation hazard inside the reactor pool, and finally on the shortening of the shut down period of the HANARO. Without a sweet of the workers of the participating company of HEC(Hyundae Engineering Co, Ltd), HDEC(HyunDai Engineering & Construction Co. Ltd), equipment manufacturer, and the task force team, it is not possible to install the FTL facility within the planned shutdown period. The Commissioning of the FTL is on due to check the function and the performance of the equipment and the overall system as well. The FTL shall start operation with high burn up test fuels in early 2008 if the commissioning and licensing progress on schedule.

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Vibration Characteristics of a Synchro Clutch Coupling for Steam Turbine (증기터빈용 Synchro Clutch Coupling의 진동 특성)

  • Shim, Eung-Gu;Lee, Tae-Gu;Moon, Seung-Jae;Lee, Jae-Heon
    • Plant Journal
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    • v.4 no.3
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    • pp.66-72
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    • 2008
  • The vibration of steam turbine is caused by Mass unbalance, Shaft misalignment, Oil whip and rubbing etc. But in turbine which is normally operated and maintained, the Mass unbalance component possesses the greatest portion. Our power plant has two steam turbines in capacity of 200 MW and 135 MW respectively and each turbine is supported by 6 journal bearings. However, we had many difficulties because the vibration amplitude of #3 and #4 Bearings was high during the start-up and operation mode change of steam turbine. But, with this study, we completely solved the vibration problem caused by the mass unbalance of #1 steam turbine. Until a recent date, #3 and #4 bearings which support high pressure turbine for #1 steam turbine had shown about $135{\mu}m$ in vibration amplitude (sometimes it increased to $221{\mu}m$ maximum. alarm: 6 mils, trip: 9 mils) at base load. After applying the study, they decreased to about $45{\mu}m$ maximum. It is a result from that we did not change the setting value of bearing alignment and only changed the assembly position of internal parts in Synchro clutch coupling rachet wheel which links between high pressure turbine and low pressure turbine, and increased the internal gap and machining of the Pawl cage surface. In the operation of steam turbine, if the vibration value increases by 1X, we should reduce the vibration of bearing by weight balancing. However, unless the vibration of bearing is declined by the balancing, we will have to disassemble and check the component and find the cause. In this study, we researched the way to lower mass unbalance that is 1X vibration component which has the greatest portion of vibration generated by steam turbine and we got good result by applying the findings of this study.

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A study on Mass Unbalance Vibration Generated from 200MW Steam Turbine Synchro Clutch Coupling (증기터빈용 Synchro Clutch Coupling에서 발생하는 진동에 관한 연구)

  • Shim, Eung-Gu;Kim, Young-Kyun;Moon, Seung-Jae;Lee, Jae-Heon
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.232-235
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    • 2008
  • The vibration of steam turbine is caused by Mass Unbalance, Shaft Misalignment, Oil Whip and Rubbing etc. but in turbine which is normally operated and maintained, the Mass Unbalance component possesses the greatest portion. Our power plant has two steam turbines in capacity of 200MW and 135MW respectively and each turbine is supported by 6 journal bearings. However, we had many difficulties because the vibration amplitude of No 3 and 4 Bearings was high during the start-up and operation mode change of steam turbine. But, with this study, we completely solved the vibration problem caused by the mass unbalance of No 1 steam turbine. Until a recent date, No 3 and 4 bearings which support high pressure turbine for No 1 steam turbine had shown about 135${\mu}$m in vibration amplitude (sometimes it increased to 221${\mu}$m maximum. alarm: 6mils, trip: 9mils) at base load. After applying the study, they decreased to about 40${\mu}$m maximum. It is a result from that we did not change the setting value of Bearing Alignment and only changed the assembly position of internal parts in Synchro Clutch Coupling Rachet Wheel which links between high pressure turbine and low pressure turbine, and increased the internal gap and machining of the Pawl stopper surface. In the operation of steam turbine, if the vibration value increases by 1X, we should reduce the vibration of bearing by weight balancing. However, unless the vibration of bearing is declined by the balancing, we will have to disassemble and check the component and find the cause. In this study, We researched the way to lower mass unbalance that is 1X vibration component which has the greatest portion of vibration generated by steam turbine and We got good result by applying the findings of this study.

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The Construction Status of Fuel Test Loop Facility (핵연료 노내조사시험설비의 시공 현황)

  • Park, Kook-Nam;Lee, Chung-Young;Kim, Hark-Rho;Yoo, Hyun-Jae;Yoo, Seong-Yeon
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.305-309
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    • 2007
  • FTL(Fuel Test Loop) is a facility that confirms performance of nuclear fuel at a similar irradiation condition with that of nuclear power plant. FTL construction work began on August, 2006 and ended on March, 2007. During Construction, ensuring the worker's safety was the top priority and installation of the FTL without hampering the integrity of the HANARO was the next one. The installation works were done successfully overcoming the difficulties such as on the limited space, on the radiation hazard inside the reactor pool, and finally on the shortening of the shut down period of the HANARO. The Commissioning of the FTL is to check the function and the performance of the equipment and the overall system as well. The FTL shall start operation with high burn up test fuels in early 2008 if the commissioning and licensing progress on schedule.

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European Globalisation Adjustment Fund (EU의 세계화조정기금 연구)

  • Lee, Ki Hwan;Kim, Hee Kil
    • International Area Studies Review
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    • v.16 no.1
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    • pp.303-325
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    • 2012
  • This paper is to provide an analysis on the European Globalisation Adjustment Fund(EGF) program and the study of European Member State. Established in December 2006, the EGF was originally intended to help workers who were affected by redundancies resulting from globalisation. The EGF at present also provides support to workers who were made redundant as a direct result of the global financial and economic crisis. In general, EGF measures are defined as assistance actions for job search, training, upskilling, outplacement, business start-up, etc. The paper focuses on the cases implemented by EGF for redundant workers harmed by globalisation and by a direct result of the global financial & economic crisis, and also focuses on the statistical portrait of the EGF 2007-2011. In addition, the paper provides criteria & implications of the EGF in the changing international economy. Finally, we could learn the importance of the EGF program through the analysis in this paper. With criteria & implications of the EGF program, the effective application to keep workers in employment or help them back into jobs would help us get over difficulties.

Development Study of Capstone Design Matching Platform based on Industry-Academic Cooperation (산학협력 캡스톤디자인 매칭 플랫폼 개발 연구)

  • Kim, Younyoung;Kim, Jaehee
    • Journal of Engineering Education Research
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    • v.26 no.2
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    • pp.3-22
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    • 2023
  • The purpose of universities is diversifying, such as education and research for the transfer of knowledge and technology, and training talented people with the competencies required in industrial sites. Therefore, universities are attempting various forms of industry-academic cooperation to maintain organic relations with companies and to conduct research activities, technology sharing, technology development, technology transfer, and human resources training. In particular, in the field of engineering education, various industry-academic cooperation programs such as field training, interns, and start-up support are actively developed and operated. Accordingly, the Engineering Education Innovation Research Information Center developed an online industry-academic cooperation capstone design matching platform for engineering education to enable collaboration between universities and companies nationwide. The industry-academic cooperation matching platform was developed under the theme of capstone design. Capstone design is a project-oriented and problem-based learning method that combines the knowledge and experiences acquired by the undergraduate department and designs and produces them. The subject of the Capstone design project was to solve corporate difficulties and allow companies and universities to collaborate. This study developed an online industry-academic cooperation capstone design matching platform according to analysis, design, development, evaluation, and execution procedures. This study is meaningful in that it has developed a channel through which students and companies, who are the subjects of industry-academic cooperation, can carry out projects and communicate organically through an online matching platform.