• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.5 no.1
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• pp.22-28
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• 1994

Previous studies reveal that in English there is no EMG evidence fur the feature tense-lax distinction. The technique of electro-myography(EMG) was used to see if the existing claim holds true, particularly in unstressed syllable. It was found that in unstressed syllable, the peak EMG amplitude from the orbicularis oris superior muscle was significantly greater in /p/ than in /b/, while in stressed syllable this difference was negligible. It was hypothesized that in stressed syllable, /p/ and /b/ may be differentiated by the EMG activities from a muscle other than the orbicularis oris superior muscle, e.g. the respiratory muscles relating to 'aspiration' or depressor anguli oris muscle. In Korean, there was a clear labial gestures for the feature tense-lax distinction. The phoneme-sensitive manifestation of stress and some possible reasons for the inter-speaker variability in the data and the variability within a given speaker were discussed.

• MALSORI
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• no.38
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• pp.125-136
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• 1999

This study examined the perception and production of Korean lax, fortis and aspirated stops in three apraxic patients. All of tile subjects made more production errors than perception errors. This indicates that apraxic patients have problems in phonetic execution rather than phonological representation. Additionally, in both production and perception, there were more errors in non-word-initial consonants than in word-initial consonants. These findings contradict those of the previous studies which report more errors in word-initial consonants. This study also found that, unlike previous studies in the types of errors made, distortion errors were high in both non-word-initial and word-initial consonants in apraxic patients. Generally, VOT of the stops showed significant differences among lax, fortis, and aspirated stops, which indicates that there is a failure not in choosing the appropriate stop but in positioning or motor planning at the articulation stage.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.154-160
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• 1998

This study describes a theoretical and experimental investigation of gas wave propagation in the pipe system. Most calculations of compressible flows in the pipe have been based on the method of characteristics. This technique has propensity to truncate waves and is difficult to apply to non-perfect gas. A method that describes the application of a two-step Lax-Wendroff acheme to solution of the unsteady one-dimentional flow in the pipe was developed. Theoretical calculations using both the method of characteristics and the two-step Lax-Wendroff method are presented including a realistic model for heat transfer and friction processes. In the present work, account is taken of the nonlinear behavior. For sections of parallel pipe, an one dimensional unsteady homentropic analysis is employed, and a numerical solution is obtained with the aid of a digital computer, using the method of characteristics and two-step Lax-Wendroff method. This analysis is then combined with boundary models, based on a quasi-steady flow approach, to give a complete treatment of the flow behavior in the pipe system.

• Journal of computational fluids engineering
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• v.4 no.2
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• pp.39-46
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• 1999

The FVM(Finite Volume Method) have been used mainly for the flow analyses in the piston-cylinder. The objective of the present study is to analyze numerically the piston-driven intake flows using the FEM(Finite Element Method). The FEM algorithm used in this study is 4-step time-splitting method which requires much less execution time and computer storage than the velocity-pressure integrated method and the penalty method. And the explicit Lax-Wendroff scheme is applied to nonlinear convective term in the momentum equations to prevent checkerboard pressure oscillations. Also, the ALE(arbitrary Lagrangian Eulerian) method is adopted for the moving grids. The calculated results show good agreement in comparison with those by the FVM and the experimental results by the LDA.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1332-1336
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• 2007

댐 제방 붕괴파는 갑작스러운 유량의 증가가 발생하여 불연속적인 흐름특성을 가지는 충격파(shock wave)가 전파되며, 갈수기 저수기에는 중소하천의 상류, 여울과 소에서의 흐름 또는 낙차공이나 보, 댐 여수로 등의 수공구조물에서 부분적인 사류 흐름이 발생된다. 이 때 흐름은 한계수위를 통과하게 되므로 기존 수치해법의 적용에 어려움이 존재한다. 본 연구에서는 실제하천에 적용될 수 있는 1차원 HLL, Roe Riemann 근사해법들을 간단히 소개하고, 시간공간적으로 2차의 고정확도 기법으로 확장하는 방법에 대하여 소개하였다. 각 기법을 정확해가 존재하는 댐붕괴 및 마른하도 전파의 경우에 적용하여 각 기법의 적용성 및 정확성을 비교하였다. 그리고 기존 Lax-Friedrichs 기법과 Lax-Wendroff 기법의 적용결과를 비교하였다. 적용결과 Lax-Friedrichs 기법을 제외한 모든 기법이 정확해와 잘 일치하였으며 특히 HLL 기법을 2차 정확도로 확장한 WAF 기법이 가장 높은 정확도로 계산되었다. 그러나 비선형 생성항이 존재하는 실제하천에 있어서 MUSCL 기법을 이용한 2차 정확도 기법이 합리적일 것으로 판단된다.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.299-306
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• 2008

Finite difference schemes are considered for a $Ca^{2+}$ diffusion equations, which discribe $Ca^{2+}$ buffering by using stationary and mobile buffers. Stability and $L^\infty$ error estimates of approximate solutions for the corresponding schemes are obtained using the extended Lax-Richtmyer equivalence theorem.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.423-424
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• 2011

Lax-Wendroff 기법을 기반의 천수방정식에 대한 유한요소 모형을 낙동강 상류부 단호교 지역에 적용하였다. 모형의 검증을 위하여 이동경계에 대한 Thacker (1981)의 정확해와 침수-노출 기법(wet-dry scheme)을 이용한 본 모형의 수치해를 비교하여 대체로 잘 일치함을 알게 되었다. 또한, U자형 만곡부를 포함한 수로의 흐름에 적용하여, 기존의 수리실험 결과, 수치모의 결과와 비교하고, 모형의 적용 가능성을 확인하였다. 낙동강 상류지역에 위치한 단호교 지역에 본 모형을 적용하고, 이를 기존 유한차분법에 의한 수치해와 비교하였다.

• East Asian mathematical journal
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• v.24 no.4
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• pp.407-414
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• 2008

Finite difference schemes are considered for a $Ca^{2+}$ diffusion equations with damping and convection terms, which describe $Ca^{2+}$ buffering by using stationary and mobile buffers. Stability and $L^{\infty}$ error estimates of approximate solutions for the corresponding schemes are obtained using the extended Lax-Richtmyer equivalence theorem.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.385-395
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• 2005

A finite element scheme is considered for the viscous Cahn-Hilliard equation with the nonconstant gradient energy coefficient. The scheme inherits energy decay property and mass conservation as for the classical solution. We obtain the corresponding error estimate using the extended Lax-Richtmyer equivalence theorem.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1247-1256
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• 2009

Finite difference schemes are considered for a nonlinear $Ca^{2+}$ diffusion equations with stationary and mobile buffers. The scheme inherits mass conservation as for the classical solution. Stability and $L^{\infty}$ error estimates of approximate solutions for the corresponding schemes are obtained. using the extended Lax-Richtmyer equivalence theorem.