• Title/Summary/Keyword: 단기응답

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Analysis of Long Term Stress and Fatigue of Semi-Submersible Drilling Platform (반잠수식 시추선의 피로 해석 연구)

  • Yu, Byung-Kun
    • Journal of Ocean Engineering and Technology
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    • v.2 no.1
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    • pp.106-115
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    • 1988
  • 반잠수식 시추선의 설계에 있어서 구조의 피로수명을 정확하게 추정하는 것은 매우 중요하며, 또한 어려운 일이다. 본 논문에서는 이미 실용화된 Aker H-3모델에 대하여 Palmgren-Miner 가정에 의하여 시추선의 hot-point인 수평 및 수직 K-brace 멤버에 대하여 피로수명을 로이드 선급의 커브에 따라 계산한 결과 북해의 해성환경 조건에서는 16년 동안 계속 작업을 할 수 있다는 결론을 얻었으나 응력 집중계수 (SCF)를 선정하는데 불확실성으로 인하여 사용하는데 주위를 요한다.

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Effects of Operational Condition and Sea States on Wave-Induced Bending Moments of Large Merchant Vessels (운항조건 및 해상상태가 대형 화물선의 파랑 중 굽힘모멘트에 미치는 영향)

  • 김동문;백점기
    • Journal of the Society of Naval Architects of Korea
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    • v.40 no.5
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    • pp.60-67
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    • 2003
  • For risk or reliability assessment of ship structures against particular hazardous situations such as total loss or sinking due to hull girder collapse, the short-term based response analysis rather than the long-term response analysis is required to determine wave-induced bending moments when the ship encounters a storm of specific duration and with a specified small encounter probability. In the present study, the effects of operational condition and sea states on wave-induced bending moments of large merchant vessels are investigated. A series of the short-term response analyses for a hypothetical VLCC and a Capesize bulk carrier (CSBC) are carried out with varying operational condition and sea states which include ship speed, significant wave height and wave persistence time, using the linear-strip theory based program ABS/SHIPMOTION and the MIT sea-keeping tables. The computed results are also compared with the IACS design formula predictions. The results and insights developed from the present study are summarized.

Full-Scale Measurement of Pure Car Carrier (자동차 운반선에 대한 실선 계측)

  • Jin-S.,Park;Oi-H.,Kim;Zae-K.,Chung
    • Bulletin of the Society of Naval Architects of Korea
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    • v.26 no.1
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    • pp.46-62
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    • 1989
  • This paper presents the results of full-scale structural measurements of 4,800 unit pure car carriers "HYUNDAI NO.103" and "HYUNDAI NO.105" on one voyage respectively for each ship, especially in order to investigate the local strength of partial bulkhead above free-board deck. With the measured data, the short-term frequency analyses have been performed. The results show that the wave-induced stresses follow, on the whole, well the Rayleigh distribution. In addition, it has been found from the measured data that transverse local stresses at bulkhead section have a very close relation with the acceleration in athwartship direction. Finally, the long-term analysis has been attempted by using the following two statistical distributions mainly in order to estimate the maximum stress amplitude at the corners of partial bulkhead. 1) Exponential distribution of cycles of stress amplitude 2) Double exponential distribution of extreme values of stress amplitude for each short-term analysis The results of these two cases show a good agreement with each other. For example, the estimated maximum stress amplitude for 10 years at port-side corner of Fr. 132 partial bulkhead is $2125kg/cm^2$ for the first case and $2170kg/cm^2$ for the second case just based on the measured data.

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애널리시스 / 국내 B2B 기업 '빛좋은 개살구'

  • Korea Database Promotion Center
    • Digital Contents
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    • no.12 s.103
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    • pp.74-75
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    • 2001
  • 올해 상반기 동안 대한 상공회의소(이하 대한상의)가 국내 B2B업체 352개사를 대상으로 B2B전자상거래 실태를 조사한 결과 응답업체의 78.6%가 경영수지가 적자 상태라고 답했으며, 수지 균형을 맞추고 있는 업체는 16.6%로 나타났다. 반면 흑자를 내고 있는 업체는 전체의 4.8%에 불과해 대부분의 업체가 경영상의 애로를 겪고 있는 것으로 드러났다. 이같이 B2B업체들이 대부분 적자상태를 면치 못하고 있는 것은 시스템 구축 등 초기 투자에 많은 비용을 지출하고 있으나 단기 수익모델 개발에는 실패했기 때문이라고 대한상의는 분석했다.

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Nonlinear Structural Safety Assessment under Dynamic Excitation Using SFEM (추계론적 유한 요소법을 이용한 동하중을 받는 비선형 구조물의 안전성 평가)

  • Huh, Jungwon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.13 no.3
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    • pp.373-384
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    • 2000
  • To assess the safety of nonlinear steel frame structures subjected to short duration dynamic loadings, especially seismic loading, a nonlinear time domain reliability analysis procedure is proposed in the context of the stochastic finite element concept. In the proposed algorithm, the finite element formulation is combined with concepts of the response surface method, the first order reliability method, and the iterative linear interpolation scheme. This leads to the stochastic finite element concept. Actual earthquake loading time-histories are used to excite structures, enabling a realistic representation of the loading conditions. The assumed stress-based finite element formulation is used to increase its efficiency. The algorithm also has the potential to evaluate the risk associated with any linear or nonlinear structure that can be represented by a finite element algorithm subjected to seismic loading or any short duration dynamic loading. The algorithm is explained with help of an example and verified using the Monte Carlo simulation technique.

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Cognitive Impairment in the Patients with Mildly Active Systemic Lupus Erythematosus (경증 전신성 홍반성 루프스 환자의 인지기능장애)

  • Kim, Jin-Hee;Lee, Chul;Lee, Chang-Uk;Paik, In-Ho
    • Korean Journal of Psychosomatic Medicine
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    • v.5 no.1
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    • pp.89-96
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    • 1997
  • This study was designed to determine whether cognitive impairment was evident in patients with SLE. Also, it aimed to examine the association of cognitive impairment with other clinical variables. The subjects consisted of 20 patients with mildly active SLE and 20 healthy controls. Methods : A total of 20 SLE patients and 20 normal controls completed a computerized neuropsychological test battery using Vienna Test System. These included Cognitrone test, Continuous attention test, Corsi block tapping test, Standard progressive matrices. Also, neuro-behavioral cognitive status examination was done. The symptom severity of depression was measured with Beck Depression Inventory, Hamilton Depression Rating Scale, and current medications were documented. Disease activity was rated using the SLE diasease activity index (SLEDAI). Results : SLE patients had poorer performance than normal controls on the tests of Cognitrone, attention, nonverbal IQ and memory, independent of age, education, disease activity, steroid use and depression status. Conclusion : Cognitive dysfunction was not uncommon in ambulatory SLE patients as measured by standardized neuropsychological tests. It seemed to occur independently of various clinical variables. These findings would suggest that cognitive dysfunction in SLE may be explained by reflecting subclinical central nervous system(CNS) involvement, rather than coexisting psychological distress due to chronic illness or side effect of medication.

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A Method on Reconfiguring job priority in Service Queue for Enhancing Operability of e-Navigation Data Service Platform (한국형 e-Navigation 대용량 데이터 처리 플랫폼의 운용성 증대를 위한 서비스 응답 큐의 우선순위 재구성 기법)

  • Kim, Myeong-hun;Kang, Moon-seog
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.10a
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    • pp.217-219
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    • 2018
  • The method on reconfiguring job priority in service queue has been developed to provide seamless service and to enhance operability of Data Service Platform(DSP) in Korean e-Navigation project that performed by Ministry of Oceans and Fisheries(MOF) since 2016. It plays a critical role for providing seamless services of DSP to expect which services ships request to DSP and how much time it costs to make services for responding them to ships in advance. Therefore, as developing a method on reconfiguring jobs in service queue of DSP with a noble algorithm to analyse priority index in parallel, DSP can provide seamless services to ships regardless of data volume and the number of requests that stacked in service queue.

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Degree of Recognition and Preparation for the Old Age Life of Public Servants (공무원들의 노후생활에 대한 인식 및 준비정도)

  • Park, Hyun-Suk;Lim, Jung-Do
    • The Journal of the Korea Contents Association
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    • v.12 no.12
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    • pp.248-260
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    • 2012
  • This study has focused on the degree of recognition and preparation for the old age life of public servants. The subjects of this research were 731 middle-aged public employees in Pusan, Ulsan, Kyeong-Nam Province. The data were collected using a self-administrated questionnaire. The following results were obtained. First, 67.2% respondents were women. Over 45-years old were 28.4%, Middle level quality of life were 46.1%, Over 20-years career were 26.7%, Administration staffs were 33.4%, and 7th grade were 31.9%. Second, In Recognition for the old age life, Respondents and their spouse have the primary responsibility of the dependent elderly. Preferred life area was suburban rural area. The order of anticipated problems of the old age life was financial problem, health problem, and leisure activity. Third, Actually, in preparation for the old age life, the order of respondents preparation was financial stability, health, and leisure activity. Forth, In the satisfaction degree of public pension for the old age life, the order of respondence was insufficient (56.0%), appropriate (17.2%), and ignorant(26.8%).

Dynamic Response of Jointed Concrete Pavement in Test Road Due to Temperature Gradient (온도구배에 의한 시험도로 줄눈콘크리트 포장의 동적응답)

  • Yoo Tae-Seok;Jeong Jin-Hoon;Han Seung-Hwan;Sim Jong-Sung
    • International Journal of Highway Engineering
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    • v.8 no.1 s.27
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    • pp.25-32
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    • 2006
  • Behavior of concrete pavement due to temperature gradient was investigated for 48 hours at test road using Falling Weight Deflectometer. The deflections at slab center changed similarly to those of ambient temperature and temperature gradients in the slab. And rapid variations in the deflections were observed between 8 to 12 in the morning. However, dynamic modulus of subgrade reaction and joint deflections showed reverse trends to the ambient temperature and temperature gradients. The dynamic modulus of subgrade reaction was significantly affected by temperature gradient when its value got higher. Backcalculated elastic moduli were obtained using AREA method and Method of Equivalent Thickness. The trends of the backcalculated elastic modulus were similar to those of dynamic modulus of subgrade reaction. Measured load transfer efficiencies showed maximum peak in the morning due to dowel locking. However, additional effort is necessary to verify the result.

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