• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.895-905
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• 1999

This paper identifies a linear time-invariant mathematical model of each stand of a five-stand tandem cold mill to design a robust $H_\infty$ thickness controller by applying input and output data sets to N4SID (Numerical algorithms for Subspace State Space System Identification) method. The input-output data sets describe interstand interference in the process of tandem cold rolling and are obtained from a nonlinear simulator of the tandem cold mill. In result, it is shown that the identified model well approximates the nonlinear model than a Taylor linearized model. Furthermore, uncertainties including roll eccentricity and incoming strip variation are quantitatively analyzed from the plot of maximum singular values.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.1-7
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• 2005

The prediction for tool life is one of the most important factors for increasing reliability, stability, and productivity of manufacturing system. This paper deals with a tool life prediction method in view of reliability assessment for cutting tools. In this study, flank wear was focused among multi-factors deciding the tool wear state. First, tool life was predicted by correlation between flank wear and cutting time, based on the extended Taylor tool life equation of turning, including parameters of cutting speed, feed rate, and cutting depth. Second, each of cutting conditions of end-milling was equivalently converted to apply ball end-mill data to the extended Taylor equation. The web-based prediction program for tool life was developed as one of reliability assessment programs for machine tools.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.6
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• pp.106-114
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• 2000

In order to evaluate the shear characteristics of undisturbed weathered granite soil which is a typical residual soil in Korea, the mechanical properties are first investigated and discussed by carrying out a series of direct shear test and then dilatancy correction is performed by using Taylor’s correction equation. In this study, specimens are sampled at Pungam(-3, -8, -13m below ground surface), Kwangju and Iksan(-5m below ground surface), Jeonbuk. The test results are summarized as follows: 1) Mohr-Coulomb failure criterion is not linear under the low confining pressure. 2) The value of cohesion is smaller than usually determined value in low pressure region. 3) The value of strength parameter c and ø which are corrected by Taylor’s correction equation is a little bit small.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.4
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• pp.96-104
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• 1991

The research effort has been focused on better calculation methods for the coefficient of consolidation under the theory of one dimensional consolidation. This research has been made available to engineers in the form of the computer program COMCv. The following conclusions can be drawn from the result of the engineering analysis, programming, and field observations. 1.Performing comparative study on six mehods(Taylor, Casagrande, Sivaram & Swamee,Su, Cour, and Scott) which can find out the coefficient of consolidation, the computer program COMCv is developed for each method. 2.Comparing the observed settlement and computed one in use of the coefficient of consolidation computed with COMCv, the result by the method of Sivaram & Swamee, Taylor, and Su is closer to the observed settlement.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.120-131
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• 1997

This paper presents an approximate reanalysis methods of structures based on substructuring for an effective optimization of large-scale structural systems. In most optimal design procedures the analysis of the structure must be repeated many times. In particular, one of the main obstacles in the optimization of structural systems are involved high computational cost and expended long time in the optimization of large-scale structures. The purpose of this paper is to evaluate efficiently the structural behavior of new designs using information from previous ones, without solving basic equations for successive modification in the optimal design. The proposed reanalysis procedure is combined Taylor series expansions which is a local approximation and reduced basis method which is a global approximation based on substructuring. This technique is to choose each of the terms of Taylor series expansions as the basis vector of reduced basis method in substructuring system which is one of the most effective analysis of large -scale structures. Several numerical examples illustrate the effectiveness of the solution process.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.31-31
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• 2003

Equatorial Plasma Bubble(EPB)은 적도 지역에서 Rayleigh-Taylor Instability에 의해 발생하는 이온층 플라즈마의 불안정성 현상으로, 주변의 플라즈마 밀도에 비해 좁은 영역에서 플라즈마 밀도가 급격하게 떨어지는 현상을 말한다. 지역적으로 보면, 겨울철에는 대서양 지역에서 집중적으로 발생하고 여름철에서는 태평양 지역에서 많이 관측된다. 이러한 불안정 현상은 단파 통신 장애를 유발할 수 있기 때문에 많은 연구 대상이 되어왔지만, 아직까지 태양 활동이나 지자기 변화에 의한 상호 연관성이 규명되지 못 하고 있다. 이것은 Rayleigh-Taylor Instability를 발생시키는 여러 인자들이 매우 복잡하게 관련되어 있기 때문인데, 본 연구에서는 특정 지역에서 발생하는 EPB에 한정하여 태양 활동과의 상호 연관성에 대해 분석하고자 하였다. 또한 단순한 발생 빈도에 대한 통계적인 처리가 아닌, EPB하나 하나에 대한 특성을 분석함으로써 EPB의 발생과 관련한 보다 명확한 분석이 가능하게 되었다. 분석에 필요한 data는 KOMPSAT-1의 Langmuir Probe(LP)에 의해 2000년에서 2001년 사이에 얻은 이온층의 전자 밀도를 사용하였는데, KOMPSAT-1의 LP는 같은 기간 활동한 다른 위성에 비해 좋은 시간 분해능을 가지고 있기 때문에 EPB의 통계 처리에 적당한 것으로 생각되었다.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.566-570
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• 2005

A digital controller for nonlinear time-delay system is proposed in this paper. A nonlinear time-delay system is discretized by using Taylor's discretization method. And the discretized system can be converted to a general nonlinear system. For this reason, general nonlinear controller synthesis can be applied to the discretized time-delay system. We adopted MAC controller synthesis for this study. Computer simulations are conducted to verify the performance of the proposed method. The results of simulation show good performance of the proposed controller synthesis and the proposed method is useful to control nonlinear time-delay system easily.

• International Journal of Control, Automation, and Systems
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• v.5 no.1
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• pp.1-7
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• 2007

In this paper, the necessary and sufficient conditions for strict positive realness of the rational transfer functions directly from basic definitions in the frequency domain are studied. A new frequency domain approach is used to check if a rational transfer function is a strictly positive real or not. This approach is based on the Taylor expansion and the Maximum Modulus Principle which are the fundamental tools in the complex functions analysis. Four related common statements in the strict positive realness literature which is appeared in the control theory are discussed. The drawback of these common statements is analyzed through some counter examples. Moreover a new necessary condition for strict positive realness is obtained from high frequency behavior of the Nyquist diagram of the transfer function. Finally a more simplified and completed conditions for strict positive realness of single-input single-output linear time-invariant systems are presented based on the complex functions analysis approach.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.4
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• pp.377-384
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• 2007

This paper studies on the relation between linearization methods and controller gains in the looper ILQ(lnverse Linear Quadratic optimal control) system for hot strip finishing mills. Firstly, two linear models arc respectively derived by a linearization method using Taylor's series expansion and a static state feedback linearization method, respectively, and the linear models are compared with the nonlinear model. Secondly, the looper servo controllers are respectively designed on the basis of two linearization models. Finally, the relation between the performances of two ILQ servo controllers and the linearization methods, and the structures and control gains of two controllers are evaluated by a computer simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.12
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• pp.1176-1181
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• 2010

This paper proposes three positioning algorithms using TOA measurements: 1) The well-known linearization method using Taylor series, 2) a modified Savarese method considering measurement noise, which does not need linearization, and 3) a modified Bancroft method where TOA measurements instead of pseudorange measurements are considered. Furthermore, through an error analysis, for Savarese method, divergence of altitude is anticipated if the transmitters are located at the same height. To prevent height divergence, the Savarese method is modified again for receivers which assumed moving on the even plane. Error analysis also shows the relationship between Bancroft and Savarese method. From the analysis it is expected that the performance of Savarese method is worse than Bancroft method because of error amplification during difference operation. Experiments using real TOA measurement from the time difference of ultra sound and RF validate the proposed methods and show that analysis is correct.