• Title/Summary/Keyword: Dissipation test

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Identification of ambient pore pressure and rigidity index from piezocone dissipation test (피에조콘 소산시험을 이용한 평형간극수압과 강성지수의 역해석)

  • 김영상
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.49-54
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    • 2002
  • This paper describes a systematic way of simultaneously identifying the ambient pore pressure and the rigidity index (=G/s$\_$u/) of soil by applying an optimization technique to the piezocone dissipation test result. An ambient pore pressure and optimal rigidity index were determined by minimizing the differences between theoretical excess pore pressures developed by Randolph & Wroth(1979) and measured excess pore pressures from piezocone using optimization technique. The effectiveness of the proposed back-analysis method was examined against the well-documented performance of piezocone dissipation tests (Tanaka & Sakagami, 1989), from the viewpoints of proper determination of selected target parameters and saving of test duration. It is shown that the proposed back-analysis method can evaluate properly the ambient pore pressure and the rigidity index by using only the early phase of the dissipation test data. Also, it is shown that with the optimized rigidity index and ambient pore pressure the proposed back-analysis method permits the horizontal coefficient of consolidation to be identified rationally.

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A Twin Symbol Encoding Technique Based on Run-Length for Efficient Test Data Compression

  • Park, Jae-Seok;Kang, Sung-Ho
    • ETRI Journal
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    • v.33 no.1
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    • pp.140-143
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    • 2011
  • Recent test data compression techniques raise concerns regarding power dissipation and compression efficiency. This letter proposes a new test data compression scheme, twin symbol encoding, that supports block division skills that can reduce hardware overhead. Our experimental results show that the proposed technique achieves both a high compression ratio and low-power dissipation. Therefore, the proposed scheme is an attractive solution for efficient test data compression.

A Novel Test Scheduling Algorithm Considering Variations of Power Consumption in Embedded Cores of SoCs (시스템 온 칩(system-on-a-chip) 내부 코어들의 전력소모 변화를 고려한 새로운 테스트 스케쥴링 알고리듬 설계)

  • Lee, Jae-Min;Lee, Ho-Jin;Park, Jin-Sung
    • Journal of Digital Contents Society
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    • v.9 no.3
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    • pp.471-481
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    • 2008
  • Test scheduling considering power dissipation is an effective technique to reduce the testing time of complex SoCs and to enhance fault coverage under limitation of allowed maximum power dissipation. In this paper, a modeling technique of test resources and a test scheduling algorithm for efficient test procedures are proposed and confirmed. For test resources modeling, two methods are described. One is to use the maximum point and next maximum point of power dissipation in test resources, the other one is to model test resources by partitioning of them. A novel heuristic test scheduling algorithm, using the extended-tree-growing-graph for generation of maximum embedded cores usable simultaneously by using relations between test resources and cores and power-dissipation-changing-graph for power optimization, is presented and compared with conventional algorithms to verify its efficiency.

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Shaking table test and numerical analysis of a combined energy dissipation system with metallic yield dampers and oil dampers

  • Zhou, Qiang;Lu, Xilin
    • Structural Engineering and Mechanics
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    • v.17 no.2
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    • pp.187-201
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    • 2004
  • A shaking table test on a three-story one-bay steel frame model with metallic yield dampers and their parallel connection with oil dampers is carried out to study the dynamic characteristics and seismic performance of the energy dissipation system. It is found from the test that the combined energy dissipation system has favorable reducing vibration effects on structural displacement, and the structural peak acceleration can not evidently be reduced under small intensity seismic excitations, but in most cases the vibration reduction effect is very good under large intensity seismic excitations. Test results also show that stiffness of the energy dissipation devices should match their damping. Dynamic analysis method and mechanics models of these two dampers are proposed. In the analysis method, the force-displacement relationship of the metallic yield damper is represented by an elastic perfectly plastic model, and the behavior of the oil damper is simulated by a velocity and displacement relative model in which the contributions of the oil damper to the damping force and stiffness of the system are considered. Validity of the analytical model and the method is verified through comparison between the results of the shaking table test and numerical analysis.

Example study of the dissipation factor change according to the oil filtering in large oil-filled transformer (유입변압기 오일필터링에 따른 유전정접 변화사례 고찰)

  • Kong, Tae-Sik;Kim, Hee-Dong
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.2035_2036
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    • 2009
  • This paper is purpose to understand the dissipation factor properties of the oil-filled large transformer according to the oil filtering. In order to know the insulation characteristic change by insulating oil filtering, we carried out the insulation diagnostic test for the same transformer before oil filtering and after. The insulation diagnosis tests are consist of the megger, the polarization index, the AC current test, the dissipation factor test and the partial discharge test, Especially we took notice of dissipation factor change, we analyzed and made a comparison of the two cases test result.

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Correlation of Piezocone Dissipation Results and Compression Index (피에조콘 소산결과와 압축지수의 상관관계)

  • Park, Young-Hwan;Kang, Beong-Joon;Lee, Jun-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1204-1211
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    • 2008
  • Compression index is one of the important characteristic numbers in soft soil engineering. Since 1940's, many researchers have suggested various practical solutions to define the compression index of clay using other soil properties. But, these results are only can give us an outline of soft soil behavior. In this study, the relationships between pore water pressure dissipation test results and compression index were suggested using comparison results of both tests. This relationships are based on basic concept of consolidation phenomena, essential difference between pore water pressure dissipation test and consolidation test, and disagreements between theoretical time factor and real time factor. To identify proportional factor of proposed equation, Geotechnical investigation results of Kwang-Yang(KY) site and Busan New Port(BN) site were used. The proportional factor was 0.0031 from 20 to 50% of consolidation rate where correlation parameter($R^2$) is 0.9051.

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Estimation of coefficient of consolidation in soft soils using PCPT dissipation results (피에조콘 소산곡선을 이용한 연약지반의 압밀계수 산정)

  • Seo, Kyung-Bum;Cho, Sung-Hwan;Lee, Jun-Hwan
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.1015-1023
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    • 2010
  • While various PCPT-based methods for the analysis of consolidation were developed, additional laboratory test is needed to estimate the coefficient of consolidation. In this paper, hyperbolic method using PCPT dissipation curve for the estimation of coefficient of consolidation was proposed. To verify proposed method, field settlement test data and PCPT dissipation test data at same site were collected and analyzed. It is observed that proposed method shows good agreement with measured field settlement data.

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Evaluation of Coefficient of Consolidation for Dilatory Dissipation Result of Piezocone Test (피에조콘 소산시험시 지연소산이 발생한 경우에 대한 압밀계수 평가 방법)

  • Ha, Tae-Gyun;Chung, Choong-Ki
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1328-1339
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    • 2008
  • For a commonly used piezocone with a shoulder filter element, dilatory dissipation behavior, which shows an initial temporary increase in pore pressure, has been observed in overconsolidated cohesive soils. However, there is no appropriate way to estimate a consolidation parameter from a dilatory dissipation curve because currently available interpretation methods were developed based on the monotonic decrease of the excess pore pressure. In this study, the interpretation method for evaluation of coefficient of consolidation from a dilatory dissipation result of piezocone test was developed by performing the finite difference analysis on the dissipation after cone penetration. The distribution of the initial excess pore pressure induced by cone penetration, which is the core of the analysis, was estimated from the empirical modification of a solution proposed by cavity expansion theory and critical state concept. And the proposed interpretation method was applied to the field piezocone data and the results were compared to those obtained from laboratory tests. Its reliability was confirmed by the insignificant difference between the values of coefficient of consolidation from piezocone tests and laboratory consolidation tests.

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Efficient Test Data Compression Method (효율적인 테스트 데이터 압축 방법)

  • Jung, Jun-Mo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.05a
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    • pp.690-692
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    • 2012
  • This pape presents the efficient test data compression method considering test power dissipation in scan test of IP core. There are many researches about test data compression using scan slice selective encoding except power dissipation. We present the new algorithm that assigns the don't care value to be a minimal hamming distance between adjacent slices. Experimental results show that the power dissipation is reduced.

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Evaluation of Similitude Laws for Dissipation Velocity of Excess Pore Pressure after Liquefaction using Impulse Load Tests (충격하중시험을 이용한 액상화 후 과잉간극수압 소산속도의 상사비 연구)

  • Kim, Dong-Hwi;Ha, Ik-Soo;Hwang, Jae-Ik;Kim, Myoung-Mo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.714-721
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    • 2004
  • The purpose of this study is to find out the similitude laws for dissipation velocity of excess pore pressure after liquefaction according to magnitude of input accelerations and height of model soils from the results of impulse load tests. In impulse load tests, model soils were constructed to the height of 25cm, 50cm, and 100cm in acrylic tubes whose inside diameters were 19cm and 38cm respectively, and impulse loads were applied at the bottom of each model soil to liquefy the entire model soil. Excess pore pressure distribution by depth and settlement of soil surface were measured in each test. Dissipation curves of excess pore pressure measured in each tests were simulated by solidification theory, and dissipation velocities of excess pore pressure were determined from the slope of simulated dissipation curves. From the results of impulse load tests, dissipation velocity of excess pore pressure was not affected by magnitude of input acceleration, and from this fact, dissipation process was proved to be different from dynamic phenomenon. However, dissipation velocity of excess pore pressure increased as height of model soil increased and showed little difference as diameter of model soil increased. Therefore, the similitude law for dissipation velocity could be expressed by the similitude law for model height to 0.2 without regard to the diameter of model soil.

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