• Title/Summary/Keyword: 과잉해 시스템

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Dynamic Characteristics of Gravity Quay Wall during Generation of Excess Pore Pressure in Backfill Soils (뒤채움지반에서의 과잉간극수압 발생이 중력식 안벽구조물의 동적특성에 미치는 영향 분석)

  • Hwang Jae-Ik;Kim Myoung-Mo
    • Journal of the Korean Geotechnical Society
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    • v.21 no.1
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    • pp.123-131
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    • 2005
  • In this research, shaking table tests for three types of gravity quay wall system were performed to analyze the influence of excess pore pressure in backfill soils on the natural frequency of gravity quay wall systems. The elastic modulus of backfill soils was also estimated from the back analyses using the results of the shaking table tests. From the test results, it was observed that as the magnitude of excess pore pressures increased, the natural frequency of the gravity quay wall system decreased and vice versa. The natural frequency was about 44Hz when no excess pore pressure was generated in backfill soils, and decreased to about 16Hz at the pore pressure ratio of 0.55. The elastic modulus of backfill soils reached the constant maximum value when the pore pressure ratio was less than 0.2, and abruptly decreased as the pore pressure ratio became larger than that. The elastic modulus of backfill soils decreased to $10\%$ of the maximum value when the pore pressure ratio was 0.55.

An Experimental Study of the Rocket Preburner Injector (로켓 산화제 과잉 예연소기 분사기의 성능특성 연구)

  • Choi, Seong-Man;Yang, Joon-Ho
    • Journal of the Korean Society of Propulsion Engineers
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    • v.11 no.1
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    • pp.57-63
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    • 2007
  • The oxidizer-rich preburner is applied to the high efficiency closed cycle rocket propulsion system. This system is generally operated on oxidizer-fuel mixture ratio over than 50. The spray quality and mixing performance are very important for stable combustion of this preburner. This paper presents basic design concept and spray characteristic of the oxidizer-rich preburner injector and this result could be applied to the development of the oxidizer rich preburner system.

A Study on Text Summarize Automation Using Document Length Normalization (문서 길이 정규화를 이용한 문서 요약 자동화에 관한 연구)

  • 이재훈;김영천;이성주
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2001.05a
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    • pp.228-230
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    • 2001
  • WWW(World Wide Web)와 온라인 정보 서비스의 급속한 성장으로 인해, 보다 많은 정보가 온라인으로 이용 혹은 접근 가능해 졌다. 이런 정보홍수로 접근 가능한 정보들이 과잉되는 문제가 발생했다. 이러한 과잉 정보 현상으로 인하여 시간적 제약이 뒤따르며 이용 가능한 모든 정보를 근거로 중요한 의사 결정을 내려야 한다. 문서 요약 자동화(Text Summarize Automation)는 이 문제를 처리하는데 필수적이다. 본 논문에서는 정보 검색을 통해 획득한 문서들을 일차적으로 문서 길이 정규화를 이용하여 질의에 적합하고 신뢰도가 더욱 높은 문서 정보를 얻을 수 있음을 보인다.

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Deformation Characteristics of Non-liquefied, Reconstituted, Weathered Residual Soils due to the Cyclic Loading (반복재하에 의한 미액상화 재성형 풍화토의 변형 특성)

  • Choi Yeon-Su;Yune Chan-Young;Jang Eui-Ryong;Chung Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.22 no.6
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    • pp.41-49
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    • 2006
  • This paper deals with development and dissipation of excess pore pressure induced by the cyclic load. Cyclic triaxial tests on reconstituted samples of weathered residual soils, which were widely used as construction materials in Korea, were performed. Test results showed that excess pore pressures developed under undrained condition increased with the increase of cyclic loads and confining pressures. And a new concept based on modified excess pore pressure ratio (MEPPR) was proposed for simply estimating excess pore pressures in terms of the number of cyclic load, irrespective of cyclic loads and confining pressures. Also, it was proposed that excess pore pressure ratio (EPPR) could be effectively utilized to estimate volumetric strains during dissipation which decreased as confining pressures increased. Consequently, concept and method to effectively estimate settlements under non-liquefied condition, induced by dynamic loads such as earthquake loads were evaluated based on laboratory test results for reconstituted weathered residual soils.

Development of Dissipation Model of Excess Pore Pressure in Liquefied Sand Ground (액상화된 모래지반의 과잉간극수압 소산모델 개발)

  • Kim, Sung-Ryul;Hwang, Jae-Ik;Ko, Hon-Yim;Kim, Myoung-Mo
    • Journal of the Korean Geotechnical Society
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    • v.23 no.10
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    • pp.13-22
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    • 2007
  • Recently, many researches on the dissipation of excess pore pressure in liquefied sand grounds have been performed to evaluate post-liquefaction behavior of structures. In this research, centrifuge tests were performed to analyze liquefaction behavior of level saturated sand grounds. Based on the test results, the evaluation model of solidified layer thickness was developed to simulate non-linear variation of the thickness with time. The thickness evaluation model was combined with the solidification theory and the consolidation theory in order to simulate dissipation of excess pore pressure. The suggested dissipation model properly estimated the solidified layer thickness and the time history of excess pore pressure.

Excess Pore Pressure Induced by Cone Penetration in OC Clay (콘관입으로 인한 과압밀점토의 과잉간극수압의 분포)

  • Kim, Tai-Jun;Kim, Sang-In;Lee, Woo-Jin
    • Journal of the Korean Geotechnical Society
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    • v.22 no.11
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    • pp.75-87
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    • 2006
  • A series of calibration chamber tests are performed to investigate the spatial distribution of the excess porewater pressure due to piezocone penetration into overconsolidated clays. It was observed that the excess porewater pressure increases monotonically from the piezocone surface to the outer boundary of the shear zone and then decreases logarithmically, approaching zero at the outer boundary of the plastic zone. It was also found that the size of the shear zone decreases from approximately 2.2 to 1.5 times the cone radius with increasing OCR, while the plastic radius is about 11 times the piezocone radius, regardless of the OCR. Based on the modified Cam clay model and the cylindrical cavity expansion theory, the expressions to predict the Initial porewater pressure at the piezocone were developed, considering the effects of the strain rate and stress anisotropy. The method of predicting the spatial distribution of excess porewater pressure proposed in this study was verified by comparing it with the porewater pressure measured in overconsolidated specimens in the calibration chamber.

Modeling and Simulation of O2/CH4 Gas Supply System of Afterburner for Fuel-rich Gas of Gas Generator (가스발생기의 연료과잉가스 후연소용 O2/CH4 가스 공급시스템 설계)

  • Wang, Seungwon;Lee, Kwangjin;Chung, Yonggahp;Han, Yeoungmin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.2
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    • pp.86-92
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    • 2014
  • Combustion Chamber Test Facility (CCTF) to be constructed in Naro Space Center for re-burning the fuel-rich gas of gas generator have afterburner system. The afterburner system is supplied the Oxygon ($O_2$) gas and Methane ($CH_4$) gas to reduced the harmful exhaust gas. The detailed design for the planned CCTF afterburner system is simulated and analysed by AMESim program through the all of gas supply system components. Afterburner system is performed to verify the pipe size, orifice diameter, and gas supply conditions according to the total gas consumption from analysis of gas supply system.

Factors of Information Overload and Their Associations with News Consumption Patterns: The Roles of Tipping Point (정보과잉 요인과 뉴스 소비 패턴의 관계: 티핑 포인트의 역할을 중심으로)

  • Sun Kyong, Lee;William Howe;Kyun Soo Kim
    • Information Systems Review
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    • v.25 no.3
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    • pp.1-26
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    • 2023
  • A theoretical model of information overload (Jackson and Farzaneh, 2012) with its three influential components (i.e., time, technology, and social networks) was empirically tested in the context of news consumption behavior considered as a communicative outcome. Using a national sample of South Korean adults (N = 1166), data analyses identified perceived information overload and large/diverse social networks positively associated with active and passive news consumption. Findings may imply the existence of individually varying cognitive threshold (i.e., tipping point), if crossed individuals cannot process information any further. News consumers may keep searching and receiving information to verify factuality of news even when they feel overloaded.

빗물배수 펌프장의 부하특성을 고려한 변압기용량 설계

  • 곽노진
    • Electric Engineers Magazine
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    • v.210 no.2
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    • pp.28-35
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    • 2000
  • 빗물펌프장은 지역침수로 인한 피해를 방지 또는 최소화시키는 것을 목적으로 한 비상 시설물이며 재해대책 시설로서 그 중요성이 커지고 있다. 여기에 그 시스템 운영에 있어서 중추적인 역할을 담당하는 기계, 전기설비 시스템의 최적화, 효율 화는 필수적이며 설비 자체의 안전과 시스템 운전안전 확보가 우선되므로 과잉설비로 계획되어 경제적인 시스템 구축이 간과될 소지가 많다.

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An Experimental Study of the Rocket Preburner Injector (로켓 프리버너 분사기의 성능특성 연구)

  • Yang, Joon-Ho;So, Youn-Seok;Choi, Hyun-Kyung;Choi, Seong-Man;Han, Young-Min
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.47-53
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    • 2006
  • The oxidizer-rich preburner is applied to the high efficiency closed cycle rocket propulsion system. This system is generally operated on oxidizer-fuel mixture ratio over than 50. The spray quality and mixing performance are very important for safe combustion of this preburner. This paper presents basic concept and spray characteristic of the preburner injector.

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