• Title/Summary/Keyword: Field behavior

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Development and Application of Construction Control System for Excavation (굴착 관리 정보화 시스템의 개발 및 적용)

  • 권오순;정충기;김재관;이해성;김명모
    • Journal of the Korean Geotechnical Society
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    • v.15 no.4
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    • pp.153-166
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    • 1999
  • Since the reliability of results by the existing analyzing method is low, in the case of for excavation performed in urban area whose stability is of great importance, construction control based on field monitoring is always necessary. But the field monitoring reflects only the behavior of construction process that has already been carried out, and it has limitations in predicting the behavior of the expected construction process, which is practically more important for construction control. In this study, construction control system for excavation which can predict the behavior of the expected processes during construction with high degree of accuracy, is developed by adopting inverse analysis. The inverse analied applied field monitoring results to excavation analysis can improve the reliability of predicted results. The developed system uses an elasto-plastic soil spring model for the excavation analysis and the minimization of least squared errors between measured displacements and calculated displacements for the inverse analysis. All the required processes for construction control can be performed as an integrated work within the system reflecting real time application and user's convenience. Their applicabilitis are confirmed by two case studies.

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Damping and vibration response of viscoelastic smart sandwich plate reinforced with non-uniform Graphene platelet with magnetorheological fluid core

  • Eyvazian, Arameh;Hamouda, Abdel Magid;Tarlochan, Faris;Mohsenizadeh, Saeid;Dastjerdi, Ali Ahmadi
    • Steel and Composite Structures
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    • v.33 no.6
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    • pp.891-906
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    • 2019
  • This study considers the instability behavior of sandwich plates considering magnetorheological (MR) fluid core and piezoelectric reinforced facesheets. As facesheets at the top and bottom of structure have piezoelectric properties they are subjected to 3D electric field therefore they can be used as actuator and sensor, respectively and in order to control the vibration responses and loss factor of the structure a proportional-derivative (PD) controller is applied. Furthermore, Halpin-Tsai model is used to determine the material properties of facesheets which are reinforced by graphene platelets (GPLs). Moreover, because the core has magnetic property, it is exposed to magnetic field. In addition, Kelvin-Voigt theory is applied to calculate the structural damping of the piezoelectric layers. In order to consider environmental forces applied to structure, the visco-Pasternak model is assumed. In order to consider the mechanical behavior of structure, sinusoidal shear deformation theory (SSDT) is assumed and Hamilton's principle according to piezoelasticity theory is employed to calculate motion equations and these equations are solved based on differential cubature method (DCM) to obtain the vibration and modal loss factor of the structure subsequently. The effect of different factors such as GPLs distribution, dimensions of structure, electro-magnetic field, damping of structure, viscoelastic environment and boundary conditions of the structure on the vibration and loss factor of the system are considered. In order to indicate the accuracy of the obtained results, the results are validated with other published work. It is concluded from results that exposing magnetic field to the MR fluid core has positive effect on the behavior of the system.

A Study on Instrumentation Results Analysis Using Artificial Neural Network in Tunnel Area (인공신경망을 이용한 터널시공 시 계측결과 분석에 관한 연구)

  • Lee, Jong-Hwi;Han, Dong-Geun;Byun, Yo-Seph;Chun, Byung-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09b
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    • pp.21-31
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    • 2010
  • Although it is important to reflect the accurate information of the ground condition in the tunnel design, the analysis and design are conducted by limited information because it is very difficult to get it practically on considering various geography and geotechnical condition. So construction management of information concept is required to manage immediately on the field condition because it is very time-consuming to establish the countermeasure of underground reinforcement and the pattern change of Bo. Therefore, when construction is on tunnel area, examination of accurate safety and prediction of behavior is performed to overcomes the limit of predicting behavior by using Artificial Neural Network(ANN) in this study. Firstly, the field data was secured. Secondly, suitable structure was made on multi-layer perceptrons among the ANN. Thirdly, learning algorithm-propagated applies to ANN. The data for the learn of field application using ANN was used by considering impact factors, which influenced the behavior of tunnel, and performing credibility analysis. crown displacement, spring displacement, subsurfacement, and rock bolt axial force are predicted at the tunnel construction and on-site application was confirmed by using ANN from analyzing and comparing with measurement value of on-site. In this study, the data from Seoul Highway $\bigcirc\bigcirc$ tunnel section was applied to the ANN Theory, and the analysis on the investigate value and the reasoning for the value associated with field application was performed.

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The Effects of Sahyangsohapwon on the Affective Reactivity and the Acquisition of Two-way avoidance in AD Model Rats (사향소합원(麝香蘇合元)이 정서반응성(情緖反應性)과 Alzheimer's disease 모델 백서(白鼠)의 학습(學習)에 미치는 영향(影響))

  • Hong Dae-Sung;Kim Jong-Woo;Whang Wei-Wan
    • Journal of Oriental Neuropsychiatry
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    • v.10 no.1
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    • pp.17-38
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    • 1999
  • The effects of Sahyangsohapwon on the affective reactivity of rats were studied with open-field behavior. Sample group was treated with the medicine for 8 weeks, whereas control group was treated with the vehicle. The effects of Sahyangsohapwon on the enhancement of learning and memory of AD model rats were studied with two-way avoidance task. Sample group electrically lesioned on nbM(nucleus basalis of Meynert) was treated with the medicine for 8 weeks, whereas control group with nbM lesion and sham group with the sham operation were treated with the vehicle. 1. In the open-field behavior task, the start latency from start box was measured $27.08{\pm}7.51sec$ in control group, $23.15{\pm}5.98sec$ in sample group. Rats in sample group showed a tendency of shortened latency going out to a strange place compared with those in control group, but with no statistical significance(p>0.05). 2. In the open-field behavior task, the number of locomotion crossing the grid lines was measured $84.54{\pm}3.55$ in control group, $116.93{\pm}6.41$ in sample group. There was an increased locomotion in sample group compared with control group with statistical significance(p<0.01). This can be interpreted as rats in sample group showed lowerd anxiety under a strange environment. 3. In the open-field behavior task, the rearing number was measured $7.46{\pm}0.57$ in control group, $10.13{\pm}0.95$ in sample group. There was an increased rearing in sample group compared with control group with statistical significance(p<0.05). This can also be interpreted as rats in sample group showed lowerd anxiety under a strange environment. 4. In the open-field behavior task, the number of crossing behavior was measured $5.54{\pm}1.50$ in control group, $9.20{\pm}1.67$ in sample group. There was a increasing tendency of crossing behavior in sample group compared with control group, but with no statistical significance(p<0.05). 5. In the open-field behavior task, the total activity was measured $97.54{\pm}4.70$ in control group, $136.27{\pm}792$ in sample group. There was an increased total activity in sample group compared with control group with statistical significance(p<0.01). This can also be interpreted as rats in sample group showed lowerd anxiety under a strange environment. 6. In the analysis of effects on the learning and memory in AD model rats with two-way avoidance task, the response latency was measured $6717{\pm}134msec$ in the 1st session, $5416{\pm}160msec$ in the 2nd session, $5252{\pm}148msec$ in the 3rd session in control group. It was measured $6724{\pm}155msec$ in the 1st session, $4642{\pm}139msec$ in the 2nd session, $4914{\pm}148msec$ in the 3rd session in sample group and $4357{\pm}144msec$ in the 1st session, $3125{\pm}115msec$ in the 2nd session, $3091{\pm}98msec$ in the 3rd session in sham group. There were differences between sham group and nbM lesioned groups with statistical significance in post hoc analysis(p<0.000). And in the 2nd session, there was a reduction of latency in sample group compared with control group with statistical significance (p<0.000). This showed that sample group had better learning capacity than control group. 7. In the analysis of effects on the learning and memory in AD model rats with two-way avoidance task, the number of avoidance response was measured $5.85{\pm}1.41$ in the 1st session, $14.23{\pm}2.89$ in the 2nd session, $15.69{\pm}2.56$ in the 3rd session in control group. It was measured $7.92{\pm}1.94$ in the 1st session, $16.83{\pm}2.29$ in the 2nd session, $15.42{\pm}2.81$ in the 3rd session in sample group and $14.38{\pm}1.62$ in the 1st session, $22.88{\pm}0.89$ in the 2nd session, $23.88{\pm}1.64$ in the 3rd session in sham group. There were differences between sham group and nbM lesioned groups with statistical significance in post hoc analysis(p<0.001). But between control and sample group, there was no significant difference. With the experimental results above, Sahyangsohapwon can be supposed to have the enhancing effects on the affect reactivity and learning with memory of AD model rats induced by electrolyte injury of nbM.

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Influencing factors on satisfaction of clinical practice field in dental hygiene students (치위생 전공 학생들의 현장실습기관 만족에 영향을 미치는 요인)

  • Seong, Mi-Gyung;Hwang, Se-Hyun;Kang, Hyun-Kyung;Jang, Kyeung-Ae
    • Journal of Korean society of Dental Hygiene
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    • v.16 no.3
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    • pp.391-399
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    • 2016
  • Objectives: The purpose of the study is to investigate the influencing factors on satisfaction of clinical practice field in dental hygiene students. Methods: A self-reported questionnaire was completed by 273 dental hygiene students in Gyeongnam from September 7 to 25, 2015 after receiving informed consent. Except incomplete answers, 269 data were analyzed. The questionnaire consisted of general characteristics of the subjects, awareness of clinical practice field satisfaction, awareness of clinical practice contents, clinical practice training, awareness of clinical practice field, future plan and behavioral change. The questionnaire was measured by Likert 5 point scale. Results: In clinical practice training, the satisfied group showed a significantly higher score than the unsatisfied group(p<0.001). In future plan and behavior change, the satisfied group showed a significantly higher score than the unsatisfied group(p<0.001). The influencing factors on clinical practice field included awareness of clinical practice field(p<0.001), awareness of clinical practice contents(p<0.001), clinical practice training(p<0.001), and future plan and behavior changes(p<0.01). Conclusions: The influencing factors on satisfaction of clinical practice field included awareness of clinical practice contents and clinical practice training, and future plan and behavioral change. It is important to develop the program for the effective clinical practice to enhance future pland behavioral change for the dental hygiene students.

Grain Growth and Texture Evolution of Mg: Phase Field Modeling (마그네슘의 결정립 성장과 집합조직: 상장모델 계산)

  • Kim, Dong-Uk;Cha, Pil-Ryung
    • Journal of Powder Materials
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    • v.18 no.2
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    • pp.168-171
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    • 2011
  • We investigate grain growth behavior of poly-crystalline Mg sheet having strong basal fiber texture using phase field model for grain growth and micro-elasticity. Strong initial basal texture was maintained when external load was not imposed, but was weaken when external biaxial strain was imposed. Elastic interaction between elastic anisotropy of Mg grain and external load is the reason why texture evolution occurs.

An analytical solution to the laminated piezoelectric beam under the electric field

  • Lin, Qirong;Jin, Zhanli;Liu, Zhengxing
    • Structural Engineering and Mechanics
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    • v.10 no.3
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    • pp.289-298
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    • 2000
  • Based on the two-dimensional constitutive relationship of the piezoelastic material, this paper derived an analytic solution to the elastic beam with the piezoelectric layer under the electric field, presented the explicit expressions of its displacement and stress. It is helpful for understanding the electrical and mechanical behavior of piezoelectric materials as actuators and the validation of the numerical methods such as FEM.

Back Analysis of Tunnel for multi-step Construction (시공 단계를 고려한 터널의 역해석에 관한 연구)

  • 김선명;윤지선
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.479-484
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    • 2000
  • The reliable estimation of the system parameters and the accurate prediction of the system behavior are important to design tunnel safely and economically. Therefore, the back analysis using the field measurements data is useful to evaluate the geotechnical parameter for tunnel. In the back analysis method, the selection of initial value and uncertainty of field measurements influence significantly on the analysis result. In this paper, to overcome uncertainty of field measurements, we performed the back analysis using the displacement data gained at each step of excavation and support.

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Magnetic Field Sensor by Using Superconductor (초전도 자기 검출소자)

  • 이상헌
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.86-88
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    • 2002
  • The relationship between electrical properties of superconductor and externally allied magnetic field was studied to develop a magnetic field polarity sensor. The behavior was related to the magnetic flux trapped in the superconductor, which penetrates through the material by the external magnetic field. Electrical characteristics of the superconductor with trapped magnetic flux were extremely sensitive ta the external magnetic field and showed different responses depending on the direction of the magnetic field. Considering the observed properties of the superconductor with trapped magnetic flux, a magnetic sensor was fabricated to detect simultaneously both the intensity and the direction of the magnetic field.

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