• Title/Summary/Keyword: Input Condition

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An $H_{\infty}$ Controller Design for linear Systems with Input Time Delay (제어 입력에 시간 지연을 갖는 선형 시스템의 $H_{\infty}$ 설계)

  • Kim, Hong-Rak;Yoo, Seog-Hwan
    • Proceedings of the KIEE Conference
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    • 1996.11a
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    • pp.42-45
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    • 1996
  • This paper presents a solution of the $H_{\infty}$ control problem for linear systems with input time delay. $H_{\infty}$ norm bounded condition is obtained as a sufficient condition for linear systems with input time delay. Based upon this sufficient condition, an $H_{\infty}$ controller design method which involves the solutions of linear matrix inequalities via convex optimization is developed.

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Evaporation Cooling of Droplet due to Surface Roughness under Radiative Heat Input Condition (복사가열조건에서 표면 거칠기에 따른 액적의 증발 냉각)

  • Bang Chang-Hoon;Kwon Jin-Sun;Yea Yong-Taeg
    • Journal of the Korean Society of Safety
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    • v.19 no.3 s.67
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    • pp.14-19
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    • 2004
  • The objective of the present work is to examine evaporation cooling of droplet due to surface roughness under radiative heat input condition. The surface temperatures varied from $80\~160^{\circ}C$ on aluminum alloy (AL 2024) and surface roughness was $0.18{\mu}m,\;1.36{\mu}m$. The results are as follows; Regardless of surface roughness under radiative heat input condition, as droplet diameter is larger, the in-depth temperature of solid decreases and evaporation time increases. In the case of $0.18{\mu}m\;and\;1.36{\mu}m$ of surface roughness, the larger the surface roughness is, the less the evaporation time is and the larger the temperature within the solid is. In the case of $Ra=0.18{\mu}m$ evaporation time and time averaged heat flux for radiative heat input case is shorter than for the conductive case.

The study on the disk grinding using neural network and Input sensitivity analysis (신경망 및 입력인자 민감도 분석을 이용한 연삭디스크의 가공조건 예측에 관한 연구)

  • 이동규;유송민;이위로;신관수
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.3-8
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    • 2004
  • When most manufacturing company produce grinding product operators decide grinding condition by experience and subjective judgment. The study on grinding manufacture have been developed to get the grinding condition with the same result when non-experienced or experienced worker work. The objective of this study is to develope the grinding condition and predict the result of grinding by neural network. Several discussions were made in following areas as; getting MRR with image processing, the architecture optimization of neural network with experiment design, analysis of the input neurons using sensitivity approach. The results showed that the developed approach was the best method in predicting grinding condition with respect to surface finish quality.

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On the ill - condition of reverse process from structural dynamic response data (구조계의 동적응답을 이용한 역해석에서의 악조건)

  • 양경택
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.390-397
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    • 1998
  • An approach to identifying input forces is proposed using measured structural dynamic responses and its analytical model. The identification of input forces is a reverse process and ill-conditioned problem. Its solution is unstable and generally case dependent. In this paper, the ill-condition is described considering characteristic matrix which is defined by reduced dynamic stiffness matrix. Special attention is focused on the condition number of a characteristic matrix used in the solution algorithm of this reverse process. Simple example is presented in support of the ill-condition of a reverse process.

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On a Sufficient Condition of Actuator Comparability for Actuator Selection LQ Problem

  • Kuwahara, Masanori;Kawaji, Shigeyasu
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.25-29
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    • 2003
  • LQ actuator selection problem for multi-input system discussed in this paper is to determine optimal actuator out of many actuators and input sequences so as to minimize the quadratic control performance. The solution of this problem depends on initial values and has a combinatorial property, so it is extremely difficult to get an optimal solution. For this difficulty, we proposed the concept of comparability of actuators and showed the uniqueness of the solution[1] . Further, to get general optimal solution for LQ problem with actuator selection strategies, we derived the equivalent condition for the comparability of actuator in single-input system . In this paper we extend this result to the case of multi-input system. The derived sufficient condition is applicable in the case of positive semi-definite comparability matrices.

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Analysis of the Parameter Convergence Rate for an Adaptive Identifier (적응추정자에 대한 파라메터 수렴속도의 해석)

  • Kim, Sung-Duck
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.2
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    • pp.127-136
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    • 1989
  • This paper describes the parameter convergence properties of an adaptive system to identify a single-input single-output plant model. It is demonstrated that, by using power spectrum analysis, the persistency of excitation (PE) condition in order to guarantee the exponential stability of the adaptive control system can be transformed into the positive definite behavior for the auto-correlation function matrix of adaptive signal. The existence of parameter nominal values can be analyzed by this condition and the convergence rates of parameter are determined by examining the auto-correlation function. We may use the sufficient richness (SR) of input spectrum instead of the PE condition to analyze the parameter boundedness. It can be shown that the eigen values of the auto-correlation function are always related with adaptive gain, input amplitude and positions or numbers of input spectra. In each case, the variation of parameter convergence rate can be also verified.

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Effect of substrate concentration on the operating characteristics of microbial electrolysis cells (기질 농도에 따른 미생물전기분해전지의 운전 특성)

  • Hwijin Seo;Jaeil Kim;Seo Jin Ki;Yongtae Ahn
    • Journal of the Korea Organic Resources Recycling Association
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    • v.31 no.4
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    • pp.41-49
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    • 2023
  • This study examined the effect of input substrate concentration on hydrogen production of microbial electrolysis cells. To compare the performance of MEC according to the input substrate concentration, six laboratory-scale MEC reactors were operated by sequentially increasing the input substrate concentration from 2 g/L of sodium acetate, to 4 g/L, and 6 g/L. The current density, hydrogen production, and SCOD removal rate were analyzed, and energy efficiency and cathodic hydrogen recovery were calculated to compare the performance of MEC. The maximum volumetric current density was obtained at 4 g/L condition (76.3 A/m3) and it decreased to 19.0 A/m3, when the input concentration was increased to 6 g/L, which was a 75% decrease compared to the 4 g/L input condition. Maximum hydrogen production was obtained also at 4 g/L condition (47.3 ± 16.8 mL), but maximum hydrogen yield was obtained at 2 g/L input condition (1.1 L H2/g CODin). Energy efficiencies were also highest in 2 g/L condition; the lowest result was observed at 6 g/L condition. Maximum electrical energy efficiency was 76.4%, and the maximum overall energy efficiency was 39.7% at 2 g/L condition. However, when the substrate concentration increased to 6 g/L, the performance was drastically decreased. Cathodic hydrogen recovery also showed a similar tendency with energy efficiency, with the lowest concentration condition showing the best performance. It can be concluded that operating at low input substrate concentration might be better when considering not only hydrogen yield but also energy efficiency.

Time-delayed State Estimator for Linear Systems with Unknown Inputs

  • Jin Jaehyun;Tahk Min-Jea
    • International Journal of Control, Automation, and Systems
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    • v.3 no.1
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    • pp.117-121
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    • 2005
  • This paper deals with the state estimation of linear time-invariant discrete systems with unknown inputs. The forward sequences of the output are treated as additional outputs. In this case, the rank condition for designing the unknown input estimator is relaxed. The gain for minimal estimation error variance is presented, and a numerical example is given to verify the proposed unknown input estimator.