• Proceedings of the KSME Conference
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• 2001.06e
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• pp.311-316
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• 2001

The thin-layer Navier-Stokes equations are solved for the hypersonic flow over blunt cone configurations with applications to laminar as well as turbulent flows. The equations are expressed in the forms of flux-vector splitting and explicit algorithm. The upwind schemes of Steger-Warming and van Leer are investigated in their ability to accurately predict the heating loads along the surface of the body. A comparison with the second order extensions of these schemes is made and a hybrid scheme incorporating a combination of central differencing and flux-vector-splitting is presented. This scheme is also investigated in its ability to accurately predict heat transfer distributions.

• Journal of the Korean Mathematical Society
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• v.42 no.5
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• pp.1087-1100
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• 2005

In this note we give the mapping properties of the Marcinkiewicz integral !-to. at some end spaces. More precisely, we first prove that !-to. is a bounded operator from H$^{1,($\mathbb{R) to H$^{1, ($\mathbb{R). As a corollary of the results above, we obtain again the weak type (1,1) boundedness of $\mu$$_{, but the condition assumed on n is weaker than Stein's condition. Finally, we show that !-to. is bounded from BMO($\mathbb{R) to BMO($\mathbb{R). The results in this note are the extensions of the results obtained by Lee and Rim recently.

• Journal of the Korean Mathematical Society
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• v.41 no.5
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• pp.821-864
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• 2004

Both parametric and parameter-free necessary and sufficient optimality conditions are established for a class of nondiffer-entiable nonconvex optimal control problems with generalized fractional objective functions, linear dynamics, and nonlinear inequality constraints on both the state and control variables. Based on these optimality results, ten Wolfe-type parametric and parameter-free duality models are formulated and weak, strong, and strict converse duality theorems are proved. These duality results contain, as special cases, similar results for minmax fractional optimal control problems involving square roots of positive semi definite quadratic forms, and for optimal control problems with fractional, discrete max, and conventional objective functions, which are particular cases of the main problem considered in this paper. The duality models presented here contain various extensions of a number of existing duality formulations for convex control problems, and subsume continuous-time generalizations of a great variety of similar dual problems investigated previously in the area of finite-dimensional nonlinear programming.

• IE interfaces
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• v.15 no.3
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• pp.241-246
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• 2002

Some extensions of minimum spanning tree problem are NP-hard problem in which polynomial-time solutions for them do not exist. Because of their complexity, recently some researcher have used the genetic algorithms to solve them. In genetic algorithm approach the Prufer number is usually used to represent a tree. In this paper we discuss the problem of the Prufer number encoding method and propose an improved genetic operation. Using a numerical comparison we demonstrate the excellence of the proposed method.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.4
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• pp.57-66
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• 1989

In this paper, a theory for the static analysis of large plastic deformations of 3-dimensional frames, aiming at application to the collapse analysis of ship structures, is presented. In the frame analysis formulation, effects of shear deformations are included. A plastic hinge is inserted into the field of a beam end, and post. failure deformation of the plastic hinge is characterized by finite rotations and extensions. In order to model deep web frames of ship's structures into a framed structures, collapse of thin-walled plate girders is investigated. The proposed analysis method is applied to several ship structural models in the references.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.40
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• pp.281-290
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• 1996

본 연구는 다품종소량 생산시스템에서 적용되는 새로운 SPC 기법에 대한 문헌을 고찰하고 검토하는데 목적이 있다. 기존의 SPC 기법은 주로 소품종 대량생산 시스템에서 적용되어 큰 효과를 보았으나 최근의 생산시스템은 다양한 수요자의 요구를 충족시킬 수 있도록 유연성 있는 다품종 소량생산체제로 이행되고 있다. 본 연구에서 사용된 분류체계는 다품종소량생산시스템의 SPC 기법을 우선 계량형과 계수형으로 크게 구분하고 계량형에서는 이를 다시 여덟 가지 차트로 계수형에서는 세 가지 차트로 재분류하여 고찰하며 향후 새롭게 적용될 수 있는 응용기법 등을 제시한다. 특히 현장의 실무진도 쉽게 접근이 가능하고 이해하기 쉽도록 기존의 SPC 기법의 대표적 분류체계인 계량형·계수형 구분방법을 사용하였다.

• The Journal of Information Technology and Database
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• v.1 no.1
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• pp.9-30
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• 1994

The objective of this paper is to give a brief review of relational design methodology, and show how a relational schema can be converted into an object-relational schema. We first introduce relational terminology and describe the relational design process along with its limitations. Next we show how the relational model can be extended to overcome these limitations : these extensions form the core of an object-relational data model ; we use the UniSQL/X data model as an example. We illustrate the process or converting a relational schema into an object-relational schema, and show the benefits of this conversion with respect to queries. The conversion process is then summarized as a set of guidelines. Finally, we make our conclusions.

• Korean Journal of English Language and Linguistics
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• v.2 no.3
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• pp.431-469
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• 2002

The main purpose of this paper is to present data about schm constructions in English and to examine them within the framework of Optimality Theory. American people sometimes reduplicate a word in deprecation using a prefix schm- or shm-, as in fancy-shmancy, and old-shmold. In these data, reduplicants surface as a copy of the whole word except the onset of the first syllable, which is replaced with schm. My data include some examples where the onset of the second syllable, not the first syllable, within the word reduplication is deleted and replaced with fixed segmentism schm, which seems to be infix rather than prefix. Above all, this study presents concrete evidence for the existence and function of ‘syllable’ and ‘foot’ known as prosodic categories by examining schm reduplication. Such extensions of schm-reduplcation also make predictions about types of outputs corresponding to their inputs.

• ETRI Journal
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• v.30 no.6
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• pp.818-825
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• 2008

This paper proposes an exponentiation method with Frobenius mappings. The main target is an exponentiation in an extension field. This idea can be applied for scalar multiplication of a rational point of an elliptic curve defined over an extension field. The proposed method is closely related to so-called interleaving exponentiation. Unlike interleaving exponentiation methods, it can carry out several exponentiations of the same base at once. This happens in some pairing-based applications. The efficiency of using Frobenius mappings for exponentiation in an extension field was well demonstrated by Avanzi and Mihailescu. Their exponentiation method efficiently decreases the number of multiplications by inversely using many Frobenius mappings. Compared to their method, although the number of multiplications needed for the proposed method increases about 20%, the number of Frobenius mappings becomes small. The proposed method is efficient for cases in which Frobenius mapping cannot be carried out quickly.

• The Pure and Applied Mathematics
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• v.13 no.4 s.34
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• pp.281-294
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• 2006

Many partial differential equations defined on a rectangular domain can be solved numerically by using a domain decomposition method. The most commonly used decompositions are the domain being decomposed in stripwise and rectangular way. Theories for non-overlapping domain decomposition(in which two adjacent subdomains share an interface) were often focused on the stripwise decomposition and claimed that extensions could be made to the rectangular decomposition without further discussions. In this paper we focus on the comparisons of the two ways of decompositions. We consider the unconditionally stable scheme, the MIP algorithm, for solving parabolic partial differential equations. The SOR iterative method is used in the MIP algorithm. Even though the theories are the same but the performances are different. We found out that the stripwise decomposition has better performance.