• Title/Summary/Keyword: Face stability

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Robust attitude control and analysis for 3-axis stabilized spacecraft using sliding mode control (슬라이딩 모드 제어를 이용한 3축 안정화 위성의 자세 제어및 강건성 해석)

  • 신동준;김진호
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.692-695
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    • 1997
  • Nonlinear robust attitude controller for 3-axis stabilized spacecraft is designed. Robust stability analysis for nonlinear spacecraft system with disturbance is conducted. External disturbances and parametric uncertainties decrease Spacecraft's attitude pointing accuracy. Sliding Mode Control(SMC) provides stability of system in the face of these disturbances and uncertainties. The concept of quadratic boundedness and quadratic stability are applied to the robust analysis for the nonlinear spacecraft system subject to bounded disturbance torques. Numerical simulation is conducted to compare the analysis result and actual nonlinear simulation. The simulation show that analysis result is valid.

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Influence of Weak Ground Ahead of the Tunnel Face on 3D-displacement and Face Extrusion (막장전방의 연약층이 터널 3차원변위 및 막장 수평변위에 미치는 영향)

  • Jeon, Je-Sung
    • Journal of the Korean Geotechnical Society
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    • v.19 no.6
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    • pp.189-206
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    • 2003
  • During tunnel excavation in urban area a systematic monitoring is important for the purpose of determination of support type and quantity, as well as for the control of stability of both surface structures and the tunnel itself due to the frequently, and in many cases, abruptly changing ground condition. In Austria absolute displacement monitoring methods have replaced relative displacement measurements by geodetic methods to a large extent. Prompt detection of weak ground ahead of the tunnel face as well as better adjustment of excavation and support to the geotechnical conditions is possible with the help of the improved methods of data evaluation on sites. Deformation response of the ground to excavation starts ahead of the tunnel face, therefore, the deformation and state of the tunnel advance core is the key factor of the whole deformation process after excavation. In other words, the rigidity and state of the advance core play a determining role in the stability of both surface structures and the tunnel itself. This paper presents the results from detailed three-dimensional numerical studies, exploring vertical displacements, vector orientations and extrusions on tunnel face during the progressive advancement for the shallow tunnel in various geotechnical conditions.

Development of usability evaluation index of convergence technology remote fluid monitoring device for non-face-to-face patient nursing system application and analysis of results (비대면 환자 간호시스템 적용을 위한 융합기술의 원격 수액모니터링 장치 사용성평가 지표 개발 및 결과 분석)

  • Kim, Seon-Chil
    • Journal of the Korea Convergence Society
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    • v.13 no.4
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    • pp.137-145
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    • 2022
  • The usability evaluation of the remote fluid monitoring device, which was introduced to reduce the work of nurses and increase the efficiency, was performed due to the expansion of the non-face-to-face medical system. Remote fluid monitoring is a fusion of various technologies such as fluid measurement and analysis, error correction technology, and transmission technology. The range of use by users, the information they want to obtain, and the control device, etc. are wide, and the factors that evaluate the product are also diverse. Therefore, it is difficult to improve the product through evaluation. In this study, a quantitative index was developed to help improve the product for commercialization by conducting 20 usability evaluations in three areas of product stability, operability, and satisfaction with the remote sap monitoring system device. It was performed through infrared and load cell-type sap monitoring devices. In terms of stability, there was a difference in installation work such as fixing the pole of the device, and high satisfaction was shown for operability and accuracy. In terms of product satisfaction, the satisfaction of load cell devices was generally high.

The Stability Evaluation of Concrete Face Rockfill Dam(CFRD) Using Settlement Measured at the Dam Crest and Kelvin Model (계측자료 및 Kelvin 모델에 의한 콘크리트 표면차수벽형 석괴댐(CFRD)의 안정성 평가)

  • Lee, Heeman;Lim, Heuidae;Cho, Gyechun;Song, Kiil
    • Journal of the Korean GEO-environmental Society
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    • v.14 no.11
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    • pp.33-46
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    • 2013
  • Recently, the projects which are to increase the capacity of the flood control are being actively performed because of the abnormal climate changes throughout the country. In this study, the regression analysis was performed using both Kelvin model and the real settlement measured at the crest of the existing concrete face rockfill dam(CFRD) to estimate the long-term deformation behavior characteristics such as creep which occurs without additional load. In addition, the effects on changes in physical properties (E, G, K) of the dam construction materials by deformation characteristics of the dam were evaluated, and the reasonable stability analysis method of the dam was proposed to obtain the long-term stability considering the changes in physical properties induced by the long-term deformation behavior in case of heightening the existing dams.

Stability Analysis of the Spillway Tunnel Located on the Granite Region Including Fault Fractured Zone (단층파쇄대를 포함한 화강암지역의 여수로 터널 안정성 분석)

  • Han, Kong-Chang;Ryu, Dong-Woo;Kim, Sun-Ki;Bae, Ki-Chung
    • Tunnel and Underground Space
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    • v.18 no.1
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    • pp.58-68
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    • 2008
  • The construction of an emergency spillway of Imha Dam is being in progress on the granite region including fault fractured zone. Considering that this tunnel is being excavated in three paralled rows, the pillar width between each tunnel and the face distance between each tunnel face were evaluated. The Influence of the fault fractured zone for the tunnel stability was investigated by numerical modelling in 3D. Various geophysical investigations and rock engineering field tests were carried out for these purposes. It was suitable that the second tunnel would be excavated in advance, maintaining the face distance between each tunnel face of minimum 25 m. The results of numerical modelling showed that the roof displacement and the convergence of the second tunnel were insignificant, and the maximum bending compressive stress, the maximum shear stress of shotcrete and the maximum axial force of rockbolt were also insignificant. Therefore, it was estimated that the stability of the spillway tunnel was ensured.

Effect of Tunnel Advance Rate on the Seepage Forces Acting on the Tunnel Face (터널굴진율이 막장에서의 침투력에 미치는 영향에 관한 연구)

  • 남석우;이인모
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.327-333
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    • 2002
  • In this study, the effect of tunnel advance rate on the seepage forces acting on the tunnel face was studied. The finite element program to analyze the groundwater flow around a tunnel with the consideration of tunnel advance rate was developed. Using the program, the parametric study for the effect of the tunnel advance rate and hydraulic characteristics of the ground on the seepage forces acting on the tunnel face was studied. From this study, it was concluded that the tunnel advance rate must be taken into consideration as an additional parameter to assess the seepage forces at the tunnel face and a rational design methodology for the assessment of support pressures required for maintaining the stability of the tunnel face was suggested for underwater tunnels.

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Chatter in Plate Milling with a Face Mill (평판의 정면밀링 가공에서 발생하는 채터)

  • 이상민;이영수;주종남
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.5
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    • pp.46-54
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    • 2004
  • A cutting force model predicting the dynamic force induced by the axial vibration of it plate in face milling is introduced. When a plate face is milled, deformation in tool axial direction is considerable. Therefore, cutting forces are affected by not only inner-outer modulation in feed direction but also by axial deformation. A PTP (peak-to-peak) diagram made by the simulated dynamic force model is evaluated. The stability of the face milling process such as the chatter outset, and the stable cutting region can be simply estimated. Simulation results are compared with that of experiment.

Measurement of Tunnel Arch Settlements Ahead of and Behind the Tunnel Face Using a Horizontal Inclinometer and Settlement Pins (수평경사계와 천단침하계에 의한 터널막장 전후방의 천단침하 계측)

  • Kim, Cheehwan
    • Tunnel and Underground Space
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    • v.23 no.2
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    • pp.120-129
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    • 2013
  • It is important to measure the displacement behind and ahead of a tunnel face during construction for evaluating mechanical stability by comparing it to a displacement criteria set by tunnel designers. The 30 m long horizontal inclinometer was installed frontward from the tunnel face and the displacement occurred ahead of a tunnel face during excavation was measured by using it. Tunnel arch settlements behind tunnel face were surveyed using a settlement pins on the arch. So total settlement and longitudinal displacement curve were obtained combining settlement measured by both the horizontal inclinometer ahead of tunnel face and the settlement pins behind the tunnel face.

Good Bank Evaluation by Chernoff Face Analysis using SAS macro faces (SAS macro faces를 사용한 체르노프 얼굴 분석에 의한 좋은 은행 평가)

  • Lee, Jeongeun;Jeong, Hyeseon;Kim, Minji;Kim, Jihyun;Son, Young Sook
    • The Korean Journal of Applied Statistics
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    • v.26 no.6
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    • pp.959-975
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    • 2013
  • The SAS macro faces program by Friendly (1992) is for Chernoff face analysis, which is one of methods for the visualization representation of multivariate data. In this paper, we examined 18 face features used in the program and presented the modified program depending on the definition of a good face in days present. In addition, a good bank evaluation for 15 domestic banks was performed through Chernoff face analysis based on 11 bank economic indicators representing stability, the consumer satisfaction, soundness, and banks profitability.