• Kyungpook Mathematical Journal
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• v.18 no.1
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• pp.37-46
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• 1978

The first part of this note is concerned with a neighbourhood base characterisation of locally order-convex spaces. The notions of order*-inductive limits and order ultrabornologicity in the class of locally order-convex spaces are introduced and studied in the latter part. These are the non-convex generalisation of o-inductive limits and o-bornological spaces.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.299-302
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• 1993

Some well known order reduction methods are briefly described and a nev order reduction technique is introduced. A comparison of the various classes of order reduction approaches are indicated. Furthermore, the question is raised how order reduction should be executed with respect to controller design. Finally, by means of an example, results of the discussed approaches are compared.

• Communications for Statistical Applications and Methods
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• v.28 no.6
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• pp.595-610
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• 2021

Recently a few articles have derived robust first-order rotatable and D-optimal designs for the lifetime response having distributions gamma, lognormal, Weibull, exponential assuming errors that are correlated with different correlation structures such as autocorrelated, intra-class, inter-class, tri-diagonal, compound symmetry. Practically, a first-order model is an adequate approximation to the true surface in a small region of the explanatory variables. A second-order model is always appropriate for an unknown region, or if there is any curvature in the system. The current article aims to extend the ideas of these articles for second-order models. Invariant (free of the above four distributions) robust (free of correlation parameter values) second-order rotatable designs have been derived for the intra-class and inter-class correlated error structures. Second-order rotatability conditions have been derived herein assuming the response follows non-normal distribution (any one of the above four distributions) and errors have a general correlated error structure. These conditions are further simplified under intra-class and inter-class correlated error structures, and second-order rotatable designs are developed under these two structures for the response having anyone of the above four distributions. It is derived herein that robust second-order rotatable designs depend on the respective error variance covariance structure but they are independent of the correlation parameter values, as well as the considered four response lifetime distributions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.961-965
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• 2010

A reduced order observer with finite time convergence characteristics is proposed for linear time invariant systems. The proposed finite time reduced order observer(FTROO) is a dual observer scheme in which two reduced order Luenberger observers with asymptotic convergence characteristics and a finite time delay element are employed. The FTROO can be constructed so as to converge in the designer specified finite time independent of the eigenvalues of the reduced order observers. A numerical example is given to show the finite-time convergence characteristics of the proposed FTROO.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.2
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• pp.103-109
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• 2001

In this paper, the prestressing order of tendons is studied to minimize a bursting force of an anchorage. The bursting forces is a primary factor of anchorage failures. The forces of the anchorage depend on the prestressing order and size of the tendons, if a lot of tendons are introduced to the anchorage. Many studies have been made to analyze the bursting force of the anchorage. However, the studies have been limited to the bursting forces of the anchorage having one or two tendons. PSC box girder bridges usually have a lot of tendons. And the difference of the bursting forces lies in the prestressing order of the tendons. As a result of the lack of studies on the prestressing order for the bridges, the order depends on the designer's intuition and experiences. It may be stated that this study should be useful for determining the reasonable prestressing order of tendons for the PSC box girder bridges.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.47.2-47
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• 2001

This paper is concerned with the limiting zeros, as the sampling period tends to zero, of a multivariable discrete-time system composed of an approximate fractional-order hold (AFROH), a continuous-time plant and a sampler in cascade. An approximate fractional-order hold is proposed to implement fractional-order hold (FROH) and is applied to instead of the zero-order hold (ZOH). The implementing problem of the fractional-order hold is overcome. The properties of the limiting zeros are studied and the location problem of them is solved. In addition, a stability condition of the zeros for sufficiently small sampling period is derived ...

• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.171-182
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• 2005

An analysis of the non-homogeneous term involved in the free surface condition for second order wave diffraction on a pair of cylinders is presented. In the computations of the nonlinear loads on offshore structures, the most challenging task is the computation of the free surface integral. The main contribution to this integrand is due to the non-homogeneous term present in the free surface condition for second order scattered potential. In this paper, the free surface condition for the second order scattered potential is derived. Under the assumption of large spacing between the two cylinders, waves scattered by one cylinder may be replaced in the vicinity of the other cylinder by equivalent plane waves together with non-planner correction terms. Then solving a complex matrix equation, the first order scattered potential is derived and since the free surface term for second order scattered potential can be expressed in terms of the first order potentials, the free surface term can be obtained using the knowledge of first order potentials only.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.1
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• pp.17-27
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• 2014

In order to study the propagation of singularities for solutions to second order quasilinear strictly hyperbolic equations with boundary, we have to consider the regularity of solutions of first order nonlinear equations satisfied by a characteristic hyper-surface. In this paper, we study the regularity compositions of the form v(${\varphi}$(x), x) with v and ${\varphi}$ assumed to have limited Sobolev regularities and we use it to prove the regularity of solutions of the first order nonlinear equations.

• Bulletin of the Korean Mathematical Society
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• v.55 no.1
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• pp.297-310
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• 2018

In this paper, a nonlinear high-order difference scheme is proposed to solve the Extended-Fisher-Kolmogorov equation. The existence, uniqueness of difference solution and priori estimates are obtained. Furthermore, the convergence of the difference scheme is proved by utilizing the energy method to be of fourth-order in space and second-order in time in the discrete $L^{\infty}-norm$. Some numerical examples are given in order to validate the theoretical results.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.4
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• pp.220-226
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• 2021

In supply chain, there are a variety of different uncertainties including demand, service time, lead time, and so forth. The uncertainty of demand has been commonly studied by researchers or practitioners in the field of supply chain. However, the uncertainty of upstream supply chain has also increased. A problem of uncertainty in the upstream supply chain is the fluctuation of the lead time. The stochastic lead time sometimes causes to happen so called the order crossover which is not the same sequences of the order placed and the order arrived. When the order crossover happens, ordinary inventory policies have difficult to find the optimal inventory solutions. In this research, we investigate the lead time distribution in case of the order crossover and explore the resolutions of the inventory solution with the order crossover.