• Title/Summary/Keyword: Fixed head

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A Study on Lateral Loading the Field Test of Pile for Large Diameter Drilled Shaft Pile (대구경 현장타설말뚝에 대한 현장수평재하시험에 관한 연구)

  • Choi, Yong-Kyu;Lee, Min-Hee;Lee, Chung-Sook
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.2
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    • pp.33-39
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    • 2004
  • Most of pile foundations are a condition of fixed head on pile, but lateral loading test of pile have performed to free head on generally. This study performed field lateral loading test accompanying lateral displacement by depth of pile for two cases(fixed head and free head) and analyzed lateral behavior of large drilled shaft. Furthermore compared theoretical equation with result of lateral loading test.

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A Study on Static Lateral Loading Test for Large Diameter Drilled Shaft Pile Considering the Pile Lead Fixity Conditions (말뚝두부구속조건을 고려한 대구경 현장타설말뚝에 대한 수평정재하시험 연구)

  • Lee, Min-Hee;Hwang, Geun-Bae;Jung, Sung-Min;Choi, Yong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.36-43
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    • 2004
  • Most of pile foundations are fixed head condition, but lateral loading test for pile is performed under free head condition generally In this study, a lateral loading test for a large diameter drilled shaft was performed under the fixed pile head and the free pile head condition, where lateral displacement along the pile depth was measure. Test results and theoretical values were compared and analyzed.

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Comprehensive evaluating the stability of slope reinforced with free and fixed head piles

  • Xixi Xiong;Ying Fan;Jinzhe Wang;Pooya Heydari
    • Geomechanics and Engineering
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    • v.32 no.5
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    • pp.523-540
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    • 2023
  • The failure of slope can cause remarkable damage to either human life or infrastructures. Stabilizing piles are widely utilized to reinforce slope as a slip-resistance structure. The workability of pile-stabilized slopes is affected by various parameters. In this study, the performance of earth slope reinforced with piles and the behavior of piles under static load, by shear reduction strength method using the finite difference software (FLAC3D) has been investigated. Parametric studies were conducted to investigate the role of pile length (L), different pile distances from each other (S/D), pile head conditions (free and fixed head condition), the effect of sand density (loose, medium, and high-density soil) on the pile behavior, and the performance of pile-stabilized slopes. The performance of the stabilized slopes was analyzed by evaluating the factor of safety, lateral displacement and bending moment of piles, and critical slip mechanism. The results depict that as L increased and S/D reduced, the performance of slopes stabilized with pile gets better by raising the soil density. The greater the amount of bending moment at the shallow depths of the pile in the fixed pile head indicates the effect of the inertial force due to the structure on the pile performance.

Cervico-ocular Reflex in Bilateral Labyrinthectomized Cats (양측 전정절제(前庭切除) 가묘(家猫)의 경안구반사(頸眼球反射))

  • Park, Byung-Rim;Park, Chul-Soon
    • The Korean Journal of Physiology
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    • v.22 no.1
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    • pp.79-88
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    • 1988
  • The effect of cervical proprioceptors on the control of eye movement and body posture was examined in unanesthetized labyrinthine intact and bilateral labyrinthectomized cats. Cervico-ocular reflex(COR) was elicited by stimulation of the cervical proprioceptors by means of sinusoidal rotation of head or body in the darkness. The following results were obtained: 1) In labyrinthine intact cats, sinusoidal rotation of the whole body elicited compensatory eye movement(vestibulo-ocular reflex: VOR); the direction of eye movement was opposite to the direction of head rotation. 2) Anticompensatory eye movement was observed by sinusoidal rotation of the body with head fixed in labyrinthine intact cats; the direction of eye movement was the same as the direction of head rotation. 3) Compensatory eye movement was observed by sinusoidal rotation of the head with body fixed or sinusoidal rotation of the body with head fixed in both acute and chronic bilateral labyrinthectomized cats. These results suggest that the cervical proprioceptors are important in the control of ocular movement and posture in the bilateral labyrintectomized cats, although they are questionable in labyrinthine intact cats.

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A study on the railway signal system for high density traffic (열차의 고밀도운전을 위한 신호보안 시스템에 관한 연구)

  • 강규현;김희식
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.163-166
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    • 1997
  • In order to shorten head-way time on existing railway lines without any change of signal block length between stations, it is a realistic optional way to change the control method of train signal, i.e. to modernize the cab signal using transponder. A new signalling system of operation pattern control technique is suggested as new model to increase the railway traffic efficiency. Through the computer simulation of this model, the train head-way time by the fixed signalling system and the new pattern control system is analyzed.

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Multi-Objective Short-Term Fixed Head Hydrothermal Scheduling Using Augmented Lagrange Hopfield Network

  • Nguyen, Thang Trung;Vo, Dieu Ngoc
    • Journal of Electrical Engineering and Technology
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    • v.9 no.6
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    • pp.1882-1890
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    • 2014
  • This paper proposes an augmented Lagrange Hopfield network (ALHN) based method for solving multi-objective short term fixed head hydrothermal scheduling problem. The main objective of the problem is to minimize both total power generation cost and emissions of $NO_x$, $SO_2$, and $CO_2$ over a scheduling period of one day while satisfying power balance, hydraulic, and generator operating limits constraints. The ALHN method is a combination of augmented Lagrange relaxation and continuous Hopfield neural network where the augmented Lagrange function is directly used as the energy function of the network. For implementation of the ALHN based method for solving the problem, ALHN is implemented for obtaining non-dominated solutions and fuzzy set theory is applied for obtaining the best compromise solution. The proposed method has been tested on different systems with different analyses and the obtained results have been compared to those from other methods available in the literature. The result comparisons have indicated that the proposed method is very efficient for solving the problem with good optimal solution and fast computational time. Therefore, the proposed ALHN can be a very favorable method for solving the multi-objective short term fixed head hydrothermal scheduling problems.

A Study on the Optimum Design of Piled-raft Foundation Considering Pile Head Condition (말뚝두부구속조건을 고려한 말뚝지지 전면기초의 최적단면 설계)

  • Cho, Jae-Yeon;Lee, Sung-June;Jeong, Sang-Seom
    • Journal of the Korean Geotechnical Society
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    • v.26 no.12
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    • pp.31-40
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    • 2010
  • This study describes the three-dimensional behavior of pile foundations based on a numerical study. A series of numerical analyses were performed for connectivity conditions between piles and cap under vertical and lateral loadings. It is shown that a fixed connection between pile and cap is able to transfer significant bending moment through the connection and increases the pile lateral stiffness and the bending moment. Based on the results obtained, it was found that the cross sectional shear force in the raft with fixed head condition was larger than that of pinned head condition. Thus, the reinforcement of pile head and thickness of the raft also increases in fixed pile head condition. From the results, it is found that the overall behavior and cross sectional forces of pile foundations is affected significantly by the pile head conditions. Furthermore, the design of pile foundations with pinned head condition was judged to be less costly and very useful for preliminary design stages.

Accuracy evaluation of treatment plan according to CT scan range in Head and Neck Tomotherapy (두경부 토모테라피 치료 시 CT scan range에 따른 치료계획의 정확성 평가)

  • Kwon, Dong Yeol;Kim, Jin Man;Chae, Moon Ki;Park, Tae Yang;Seo, Sung Gook;Kim, Jong Sik
    • The Journal of Korean Society for Radiation Therapy
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    • v.31 no.2
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    • pp.13-24
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    • 2019
  • Purpose: CT scan range is insufficient for various reasons in head and neck Tomotherapy®. To solve that problem, Re-CT simulation is good because CT scan range affects accurate dose calculations, but there are problems such as increased exposure dose, inconvenience, and a change in treatment schedule. We would like to evaluate the minimum CT scan range required by changing the plan setup parameter of the existing CT scan range. Materials and methods: CT Simulator(Discovery CT590 RT, GE, USA) and In House Head & Neck Phantom are used, CT image was acquired by increasing the image range from 0.25cm to 3.0cm at the end of the target. The target and normal organs were registered in the Head & Neck Phantom and the treatment plan was designed using ACCURAY Precision®. Prescription doses are Daily 2.2Gy, 27 Fxs, Total Dose 59.4Gy. Target is designed to 95%~107% of prescription dose and normal organ dose is designed according to SMC Protocol. Under the same treatment plan conditions, Treatment plans were designed by using five methods(Fixed-1cm, Fixed-2.5cm, Fixed-5cm, Dynamic-2.5cm Dynamic-5cm) and two pitches(0.43, 0.287). The accuracy of dose delivery for each treatment plan was analyzed by using EBT3 film and RIT(Complete Version 6.7, RIT, USA). Results: The accurate treatment plan that satisfying the prescribed dose of Target and the tolerance dose in normal organs(SMC Protocol) require scan range of at least 0.25cm for Fixed-1cm, 0.75cm for Fixed-2.5cm, 1cm for Dynamic-2.5cm, and 1.75cm for Fixed-5cm and Dynamic-5cm. As a result of AnalysisAnalysis by RIT. The accuracy of dose delivery was less than 3% error in the treatment plan that satisfied the SMC Protocol. Conclusion: In case of insufficient CT scan range in head and neck Tomotherapy®, It was possible to make an accurate treatment plan by adjusting the FW among the setup parameter. If the parameter recommended by this author is applied according to CT scan range and is decide whether to re-CT or not, the efficiency of the task and the exposure dose of the patient are reduced.

Model verification and assessment of shear-flexure interaction in pile foundations

  • Lemnitzer, Anne;Nunez, Eduardo;Massone, Leonardo M.
    • Earthquakes and Structures
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    • v.11 no.1
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    • pp.141-163
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    • 2016
  • Fiber models have been developed and applied to various structural elements such as shear walls, beams and columns. Only scarcely have fiber models been applied to circular foundation systems such as cast in drilled holes shafts (CIDH). In pile foundations with constraint head boundary conditions, shear deformations can easily contribute to the lateral pile response. However, soil structure interaction formulations such as the p-y method, commonly used for lateral pile design, do not include structural shear deformations in its traditional derivation method. A fiber model that couples shear and axial-bending behavior, originally developed for wall elements was modified and validated on circular cross sections (columns) before being applied to a 0.61 m diameter reinforced concrete (RC) pile with fixed head boundary conditions. The analytical response was compared to measured test results of a fixed head test pile to investigate the possible impact of pile shear deformations on the displacement, shear, and moment profiles of the pile. Results showed that shear displacements and forces are not negligible and suggest that nonlinear shear deformations for RC piles should be considered for fixed-head or similar conditions. Appropriate sensor layout is recommended to capture shear deformation when deriving p-y curves from field measurements.

The effects of the methods of eye gaze and visual angles on accuracy of P300 speller (시선응시 방법과 시각도가 P300 문자입력기의 정확도에 미치는 영향)

  • Eom, Jin-Sup;Sohn, Jin-Hun
    • Science of Emotion and Sensibility
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    • v.17 no.2
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    • pp.91-100
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    • 2014
  • This study was to examine how visual angle of matrix corresponding to the physical properties of P300 speller and eye gaze corresponding to the user's personal characteristics influence on the accuracy of P300. Visual angle of the matrix was operated as the distance between the user and the matrix and three groups were composed: 60 cm group, 100 cm groups, and 150 cm group. Eye gaze methods was consisted three conditions. Head moving condition was putting eye gaze using head, pupil moving condition was moving pupil with the head fixed, while the eye fixed condition is to fix the eye gaze at the center of the matrix. The results showed that there was significant difference in the accuracy of P300 speller according to the eye gaze method. The accuracy of the head moving condition was higher than the accuracy of pupil moving conditions, accuracy of pupil moving conditions was higher than the accuracy of the eye fixed conditions. However, the effect of visual angle of matrix and interaction effect were not significant. When P300 amplitude of target character was measured depending on how you stare at the target character, P300 amplitude of the head moving condition was greater than P300 amplitude of the pupil moving condition. There was no significant difference in the error distribution in head moving condition and pupil moving condition, while there was a significant difference between two eye gaze conditions and fixed gaze condition. The error was located at the neighboring characters of the target character in head moving condition and pupil moving condition, while the error was relatively distributed widely in fixed eye condition, error was occurred with high rate in characters far away from the center of matrix.