• Water Engineering Research
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• 제2권3호
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• pp.151-160
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• 2001

A two-dimensional flow model is newly developed. Two-dimensional shallow-water equations are discretized by the finite volume method. A nonorthogonal coordinate system is then employed. The developed model is applied to simulations of flows in a 180 degree curved bend flow. Numerical prediction are compared to available laboratory measurement. A good agreement is observed.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1684-1692
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• 2016

In order to adapt the fast dynamic performances of Buck DC/DC converter, and reduce the influence on converter performance owing to uncertain factors such as the disturbances of parameters and load, a control strategy based on two-dimensional hybrid cloud model is proposed. Firstly, two cloud models corresponding to the specific control inputs are determined by maximum determination approach, respectively, and then a control rule decided by the two cloud models is selected by a rule selector, finally, according to the reasoning structure of the rule, the control increment is calculated out by a two-dimensional hybrid cloud decision module. Both the simulation and experiment results show that the strategy can dramatically improve the dynamic performances of the converter, and enhance the adaptive ability to resist the random disturbances, and its control effect is superior to that of the current-mode control.

• 한국자동차공학회논문집
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• 제3권1호
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• pp.97-107
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• 1995

Global postbuckling analysis is accomplished for one-dimensional and two-dimensional delaminations. A new finite element model, which can be used to model the global postbuckling analysis of one-dimensional and two-dimensional delaminations, is presented. In order to calculate the strain energy release rate, geometrically nonlinear analysis is accomplished, and the incremental crack closure technique is introduced. To check the effectiveness of the finite element models and the incremental crack closure technique, the simplified closed-form sloution for a through-the-width delamination with plane strain condition is derived and compared with the finite element result. The finite element results show good agreement with the closed-foul1 solutions. The present method was extended to calculate the strain energy release rate for two-dimensional delamination. For a symmetric circular delamination, the strain energy release rate shows great variation along the delamination front. and the delamination growth appears to occur perpendicular to the loading direction.

• 한국해안해양공학회지
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• 제7권2호
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• pp.176-197
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• 1995

한국경남해역의 2차원 및 3차원적 조류구조를 동적원리에 근거한 수치모형을 통하여 조사하였다. 2차원 수치모형을 이용하여 주 8개 분조(M$_2$, S$_2$, $K_1$, $O_1$, $N_2$, $K_2$, P$_1$, Q$_1$)에 대한 조석체계를 계산하였다. 계산결과는 해안의 관측치와 비교하여 만족할만한 일치를 보였다. 이러한 결과를 토대로 하여 매년 적조등으로 인해 심각한 오염이 발생되고 있는 진해만과 마산만의 3차원적 조석순환구조를 조사하기 위하여 기 수립된 2차원 모형과 내만의 3차원 모형을 연결시키도록 개선하였다. 그 방법으로 Davies(1980)가 제시한 2차원 수심적분 모형과 3차원 Galerkin-Spectral 모형과의 동적연결방법을 이용하였다. Davies의 연구에 추가하여 본 연구에서는 3차원 수치모형에 자승형마찰항과 비선형 이류항을 추가하였다. 3차원 모형에서 산정된 각 수심별 M$_2$ 분조의 조류타원도는 KORDI(1990)가 수행한 수심별 조류관측치와 양호한 일치를 보였다.

• 한국전자통신학회논문지
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• 제8권9호
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• pp.1365-1371
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• 2013

표면상에서의 흡착현상 중, 특정한 압력에서 흡착량이 불연속적으로 급격하게 증가하는 2상 공존현상을 이론적으로 설명하기 위하여 2차원 클러스트 응집모형을 도입하였다. 이 2차원 클러스트 응집모형에 기초적인 통계열역학과 미정계수법을 적용하여 흡착등온식을 유도하였으며, 유도된 흡착등온식은 표면흡착에서의 2상 공존현상이 흡착입자들 간의 강한 인력에 의한 것임을 정성적으로 잘 보여주었다.

• 한국수자원학회논문집
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• 제51권11호
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• pp.971-976
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• 2018

관망의 해석은 관망의 설치, 운영에서 매우 중요한 요소이다. 이를 위한 연구 방법은 1차원 모형과 3차원 모형이 있으나 각각은 정확도와 계산속도의 면에서 관망 해석에 장점과 한계점을 보인다. 2차원 모형의 경우 1차원 모형과 달리 난류 점성을 이용하여 보다 정확한 마찰을 모의할 수 있게 하는데, 이때 사용되는 난류 점성을 모의하는 모형은 Five-Region Turbulence Model을 이용하였다. 그러나 이들 모형에 사용되는 매개 변수들은 실험에 의한 값이기 때문에 이러한 매개변수에 따른 2차원 부정류 해석 방법의 응답 특성을 알아보았다. 이를 위해 실제 상수관망에서의 수격압 데이터와 부정류 해석 모형으로 부터의 수격압 데이터를 비교하고, 다양한 매개변수에 따른 속도 분포 모의 특성을 조사하였다. 이를 통해서, 난류해석 모형의 마찰 거동과 매개변수와의 관계를 규명하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.406-406
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• 2005

• 한국환경과학회지
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• 제17권9호
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• pp.957-968
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• 2008

The purpose of this study is to analyze the characteristics of hydraulic behavior of the natural channel flow according to the temporal classification mode, and thus propose the hydraulic analysis method for future channel design. For analysis, the temporal flow characteristics of the channel section was divided into the steady flow and the unsteady flow. For hydraulic analysis, the HEC-RAS model, which is a one-dimensional numerical analysis model, and the SMS-RAM2 model, which is a two-dimensional model, were used and the factors used for analysis of hydraulic characteristics were flood elevation and flow rate. The flow state was analyzed on the basis of the one-dimensional steady flow and unsteady flow for review. In the unsteady flow analysis the flow rate changed by $(-)0.16%{\sim}(+)0.26%$, and the flood elevation varied by $(-)0.35%{\sim}(+)0.51%$ as compared to the values in the steady flow analysis. Given these results, in the one-dimensional flow analysis based on the unsteady flow the flood elevation and flow rate were greater than when the analysis was done on the basis of the steady flow. The flow state was analyzed on the basis of the two-dimensional steady flow and unsteady flow. In the unsteady flow analysis the flow rate varied by $(-)0.16%{\sim}(+)1.08%$, and the flood elevation changed by $(-)0.24%{\sim}(+)0.41%$ as compared to the values in the steady flow analysis. Given these analysis results, in the two dimensional flow analysis based on the unsteady flow, the flood elevation and flow rate were greater than when the analysis was done on the basis of the steady flow.

• 품질경영학회지
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• 제35권1호
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• pp.136-141
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• 2007

For many products failures depend on age and usage and, in this case, failures are random points in a two-dimensional plane with the two axes representing age and usage. Models play an important role in decision-making. In this research, an accelerate failure test (AFT) model is proposed to deal with the two-dimensional data. The parameters are proposed to be estimated through maximum likelihood estimators.

• 대한안전경영과학회지
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• 제19권1호
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• pp.157-167
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• 2017

The two-way quality theory has been widely used as a method for classifying quality attributes for several decades. In particular, the Kano model that classifies attributes into not just conventional one-dimensional but must-be and attractive has gained popularity due to its applicability and ease of use. However, the wordings of the five alternatives in the Kano's questionnaire has been criticised for unclear meanings. This study proposes a new two-way model to classify attributes using 5-point Likert scale alternatives. For this, the current paper investigated a case of TV sets to examine how the proposed model works in comparison with the Kano model. The application results of the proposed model are different from the original one. The two-way model classifies quality attributes in more detail such as the "one-dimensional with an attractive tendency" attribute, which has a greater influence on satisfaction than dissatisfaction, the opposite "one-dimensional with a must-be tendency" attribute, and "highly one-dimensional" and "less one-dimensional" attributes. In this study, a potential satisfaction coefficient (PSC), a potential dissatisfaction coefficient (PDC), and an average potential coefficient (APC) to manage quality attributes are proposed and discussed for their utilization.