• Title/Summary/Keyword: Pivot

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Nonlinear Analysis Models to Predict the Hysteretic Behavior of Existing RC Column Members (기존 RC 기둥 부재의 이력거동 예측을 위한 비선형 해석모델)

  • Choi, Myeong-Ho;Lee, Chang-Hwan
    • Journal of Korean Association for Spatial Structures
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    • v.22 no.4
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    • pp.89-98
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    • 2022
  • The recent earthquake in Korea caused a lot of damage to reinforced concrete (RC) columns with non-seismic details. The nonlinear analysis enables predicting the hysteresis behavior of RC columns under earthquakes, but the analytical model used for the columns must be accurate and practical. This paper studied the nonlinear analysis models built into a commercial structural analysis program for the existing RC columns. The load-displacement relationships, maximum strength, initial stiffness, and energy dissipation predicted by the three analysis models were compared and analyzed. The results were similar to those tested in the order of the fiber, Pivot, and Takeda models, whereas the fiber model took the most time to build. For columns subjected to axial load, the Pivot model could predict the behavior at a similar level to that of the fiber model. Based on the above, it is expected that the Pivot model can be applied most practically for existing RC columns.

Study of Relationship on TaiYin-disease between the Chapter of Channels in Miraculous Pivot of Emperor's Classic of Internal Medicine and in ShangHanRun (『영추ㆍ경맥편』과 『상한론』의 태음병의 상관성 연구)

  • Lee Seung Yeul;Kim Yon Tae;Shin Heung Mook
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.18 no.2
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    • pp.396-400
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    • 2004
  • The oriental medical doctors who had studied Shang Han Run thought highly of meridians and until now it was generally known that the chapter of heat in the Plain Questions of Emperor's Classic Internal Medicine(ECIM: 皇帝內經, 素門, 熱論) was the basis of Shang Han Run. The chapter of heat in the Plain Questions of ECIM was the first text in which the basic theory on six-channels according to the types of illness was introduced. In my point of view, the theory of treating six-channels had close relation to the Chapter of Channels in Miraculous Pivot of ECIM(皇帝內經, 靈樞ㆍ經脈篇) as well as the chapter of heat in the Plain Questions of ECIM. Therefore I took a look at the origin of treating six-channels in Shang Han Lun and illuminated again the meaning to compare the parts of in Shang Han Lun with the Chapter of Channels in Miraculous Pivot of ECIM. Conclusion : The symptoms of TaiYin-channel(太陰經) in the Chapter of Channels in Miraculous Pivot of ECIM were, for the most part, accord with those of TaiYin-disease in Shang Han Lun. Furthermore, the symptoms in Shang Han Lun were explained definitely and in detail. Therefore the theory of Shang Han Lun has been developed on the basis of ECIM with the changes of the times. TaiYin-disease implied symptoms of pi-spleen meridian(脾經) and fei-lung meridian(肺經). Therefore Shang Han Lun was the foundation of treatment based on overall analysis of signs and symptoms(辨證論治) in respect of meridian as well as the text in which the steps of infectious diseases(外感病) of human bodies were explained.

An Implementation of Efficient Quicksort Utilizing SIMD-Based VBP Technique (SIMD 기반의 VBP 기법을 적용한 효율적인 퀵정렬의 구현)

  • Hong, Gilseok;Kim, Hongyeon;Kang, Seonghyeon;Min, Jun-Ki
    • KIISE Transactions on Computing Practices
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    • v.23 no.8
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    • pp.498-503
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    • 2017
  • SIMD (Single Instruction Multiple Data) is a representative parallelization architecture that processes multiple data loaded in a SIMD register with a single instruction. Quicksort is a sorting algorithm that picks an element as a pivot from the array and reorders the array such that all elements having the values less than the pivot value are located in the left side on the pivot as well as all elements having the value greater than the pivot value are located in the right side on the pivot and then the algorithm performs the same task on both sublist recursively. In this paper, we propose an efficient Quicksort algorithm applying the SIMD instructions which minimally invokes conditional branches to avoid the performance degradation incurred by branch misprediction in a pipeline architecture. In addition, we improve the performance of the Quicksort algorithm by fetching data into a SIMD register as a byte unit to apply VBP (Vertical Bit Parallel) and the early pruning technique.

A study on the Gal Do(骨度) of the Young Chu(靈樞) (영추(靈樞).골도(骨度)에 대(對)한 연구(硏究))

  • Du, Ja-Sung;Roh, Stella;Lee, Tae-Ho;Lee, Young-Sub;Keum, Kyoung-Su;Jeong, Heon-Young
    • Journal of Korean Medical classics
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    • v.19 no.3
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    • pp.305-313
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    • 2006
  • According to the bone-standard measuring, the length between the elbow and the wrist has the span of 1.25 cheoks whereas it has the span of 1.2 cheoks or 1.2 cheoks today, the breadth of the chest has the span of 9.5 chons whereas it has the span of 8 chons today, and the length from celestial pivot to transverse bone has the span of 6.5 chons whereas it has the span of 5 chons, and the length from free rib region to thigh pivot has the span of 6 chons whereas it has the span of 9 chons today. It is said that all of the acupuncture points are correctly prescribed by the bone-standard measuring irrespective of men and women of all ages, fat and lean, and whether large or small in height. This lies at the root of the selecting acupuncture points. The bone standard in Spiritual Pivot and that in common use at present have a little difference and the bone standard of today is based upon A-B Classic. Spiritual Pivot named as Acupuncture Classic was in good preservation until the mid-eleventh century, but the book lost a lot in contents was the incomplete edition. In the 8th year of the king Cheoljong's reign of the North Song Dynasty in 1093, though the nine-volume Spiritual Pivot drafted from the Goryo Dynasty was published, the book was wanting in consistency. While on the other, I think that A-B Classic which has been in a state of perfection had a great influence on the healers of the day.

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Learning Multiple Instance Support Vector Machine through Positive Data Distribution (긍정 데이터 분포를 반영한 다중 인스턴스 지지 벡터 기계 학습)

  • Hwang, Joong-Won;Park, Seong-Bae;Lee, Sang-Jo
    • Journal of KIISE
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    • v.42 no.2
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    • pp.227-234
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    • 2015
  • This paper proposes a modified MI-SVM algorithm by considering data distribution. The previous MI-SVM algorithm seeks the margin by considering the "most positive" instance in a positive bag. Positive instances included in positive bags are located in a similar area in a feature space. In order to reflect this characteristic of positive instances, the proposed method selects the "most positive" instance by calculating the distance between each instance in the bag and a pivot point that is the intersection point of all positive instances. This paper suggests two ways to select the "most positive" pivot point in the training data. First, the algorithm seeks the "most positive" pivot point along the current predicted parameter, and then selects the nearest instance in the bag as a representative from the pivot point. Second, the algorithm finds the "most positive" pivot point by using a Diverse Density framework. Our experiments on 12 benchmark multi-instance data sets show that the proposed method results in higher performance than the previous MI-SVM algorithm.

Rotordynamic Performance Predictions of Tilting Pad Journal Bearing with Rocker-Back Pivots and Comparison with Published Test Results (로커-백 피벗을 갖는 틸팅 패드 저널 베어링의 회전체동역학적 성능 예측 및 기존 결과와의 비교)

  • Kim, Tae Ho;Choi, Tae Gyu;Kim, Choong Hyun
    • Tribology and Lubricants
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    • v.31 no.6
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    • pp.294-301
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    • 2015
  • In this paper, we predict the rotordynamic force coefficients of tilting pad journal bearings (TPJBs) with rocker-back pivots, and we compare the predictions to recently published predictions and test data. The present TPJB model considers the rocker-back pivot stiffness calculated based on the Hertzian contact-stress theory, which is nonlinear with the application of a force . For the five-pad TPJB in load-between-pad and load-on-pad configurations, the predictions show the pressure- and film-thickness distributions, the deflection and stiffness of the individual pivots, and bearing stiffness and damping coefficients. The minimum film thickness and peak pressure occur at the bottom pad on which the applied load is directed. Because of the preload, the pres- sure is positive even at the upper pad in the opposite direction to the applied load. The pivot deflection and stiff- ness are maximum at the bottom pad that receives the heaviest pressure load. The predicted stiffness coefficients increase as the static load and rotor speed increase, while the damping coefficients decrease as the rotor speed increases, but increase as the static load increases. In general, the predicted stiffness coefficients agree well with the test data. The predicted damping coefficients overestimate the test data, particularly for large static loads. In general, the current predictive model considering the pivot stiffness improves the accuracy of the rotordynamic performance compared to previously reported models.

Experimental verification of leverage-type stiffness-controllable tuned mass damper using direct output feedback LQR control with time-delay compensation

  • Chu, Shih-Yu;Yeh, Shih-Wei;Lu, Lyan-Ywan;Peng, Chih-Hua
    • Earthquakes and Structures
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    • v.12 no.4
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    • pp.425-436
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    • 2017
  • Vibration control using a tuned mass damper (TMD) is an effective technique that has been verified using analytical methods and experiments. It has been applied in mechanical, automotive, and structural applications. However, the damping of a TMD cannot be adjusted in real time. An excessive mass damper stroke may be introduced when the mass damper is subjected to a seismic excitation whose frequency content is within its operation range. The semi-active tuned mass damper (SATMD) has been proposed to solve this problem. The parameters of an SATMD can be adjusted in real time based on the measured structural responses and an appropriate control law. In this study, a stiffness-controllable TMD, called a leverage-type stiffness-controllable mass damper (LSCMD), is proposed and fabricated to verify its feasibility. The LSCMD contains a simple leverage mechanism and its stiffness can be altered by adjusting the pivot position. To determine the pivot position of the LSCMD in real time, a discrete-time direct output-feedback active control law that considers delay time is implemented. Moreover, an identification test for the transfer function of the pivot driving and control systems is proposed. The identification results demonstrate the target displacement can be achieved by the pivot displacement in 0-2 Hz range and the control delay time is about 0.1 s. A shaking-table test has been conducted to verify the theory and feasibility of the LSCMD. The comparisons of experimental and theoretical results of the LSCMD system show good consistency. It is shown that dynamic behavior of the LSCMD can be simulated correctly by the theoretical model and that the stiffness can be properly adjusted by the pivot position. Comparisons of experimental results of the LSCMD and passive TMD show the LSCMD with less demand on the mass damper stroke than that for the passive TMD.

Induced Magnetic Anisotropy of Sputtered FeN Films Due to Substrate Tilting

  • Park, Y.;S. Ryu;S. Jo
    • Journal of Magnetics
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    • v.2 no.1
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    • pp.22-24
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    • 1997
  • FeN thin films were deposited by RF-reactive diode sputtering to investigate magnetic characteristics variation due to substrate tilt during the film deposition, and their magnetic properties were measured by VSM, SEM and AFM. When the substrate tilt pivot edges were parallel to the applied field, the magnetic anisotropy was increased When the substrate tilt pivot edges were perpendicular to the applied field, the easy magnetization axis became the hard magnetization axis, and the hard axis became the easy axis as the tilt angles were increased. The reason is believed to be due to the fact that the tilt induced shape magnetic anisotropy became larger than the field induced magnetic anisotropy by DC magnetic field as the crystal grains are enlongated along the substrate tilt pivot edges due to "oblique incidence anisotropy" commonly found in eveporated thin films.

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Performance Evaluation of a Pivot-Type Displacement Amplification Damper System for Seismic Strengthening (내진보강을 위한 피봇형 변위 증폭 감쇠 시스템의 성능 평가)

  • Park, Jang-Ho;Ahn, Sung-Chan;Park, Kwan-Soon
    • Journal of the Korean Society of Safety
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    • v.27 no.1
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    • pp.70-75
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    • 2012
  • For the vibration control of earthquake-excited structures, a pivot-type displacement amplification damper system is proposed and its validity is investigated in this study. A rotational frame amplifies the stroke of the proposed damper system and it can absorb more vibrational energy compared to the conventional dampers of which strokes are not large. In order to prove the effectiveness of the system, time-history analyses are performed with a three story building modelled by a three dimensional frame and numerical results are compared with those for a conventional V-shape braced damper system. In addition, the seismic performances are investigated according to the changes of damper capacity and location.

Lateral Force Calibration in Liquid Environment using Multiple Pivot Loading (Multiple Pivot loading 방법을 이용한 액체 환경에서의 수평방향 힘 교정)

  • Kim, Lyu-Woon;Chung, Koo-Hyun
    • Tribology and Lubricants
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    • v.29 no.2
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    • pp.91-97
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    • 2013
  • Quantifying the nanoscale force between the atomic force microscopy (AFM) probe of a force-sensing cantilever and the sample is one of the challenges faced by AFM researchers. The normal force calibration is straightforward; however, the lateral force is complicated due to the twisting motion of the cantilever. Force measurement in a liquid environment is often needed for biological applications; however, calibrating the force of the AFM probes for those applications is more difficult owing to the limitations of conventional calibration methods. In this work, an accurate nondestructive lateral force calibration method using multiple pivot loading was proposed for liquid environment. The torque sensitivity at the location of the integrated probe was extrapolated based on accurately measured torque sensitivities across the cantilever width along a few cantilever lengths. The uncertainty of the torque sensitivity at the location of the integrated tip was about 13%, which is significantly smaller than those for other calibration methods in a liquid environment.