• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제17권3호
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• pp.209-219
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• 2013

The present paper deals with the extension of AUSMPW+ scheme into two-fluid model for multiphase flow. AUSMPW+ scheme is the improvement of a single-phase AUSM+ scheme by designing pressure-based weighting functions to prevent oscillations near a wall and shock instability after a strong shock. Recently, Kitamura and Liou assessed a family of AUSM-type schemes with two-fluid model governing equations [K. Kitamura and M.-S. Liou, Comparative study of AUSM-Family schemes in compressible multi-phase flow simulations, ICCFD7-3702 (2012)]. It was observed that the direct application of the single-phase AUSMPW+ did not provide satisfactory results for most of numerical test cases, which motivates the current study. It turns out that, by designing pressure-based weighting functions, which play a key role in controlling numerical diffusion for two-fluid model, problems reported in can be overcome. Various numerical experiments validate the proposed modification of AUSMPW+ scheme is accurate and robust to solve multiphase flow within the framework of two-fluid model.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.490-493
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• 2005

In order to reduce the harmonics in invertor output of the DVR system, typically LC filter is employed. In designing the LC filter, it is required to consider the gild impedance and the characteristic of the harmonics. In this paper, problems in the conventional way of designing the LC filter is analyzed and new LC fitter design technique is proposed. In the proposed technique, parameters of the LC filter are calculated considering grid impedance, THD, DC link voltage and phase lag. The validity and feasibility of the proposed method is verified through the simulations experiments. The DVR system with the proposed LC filter is being built and tested.

• 산업공학
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• 제18권4호
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• pp.402-411
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• 2005

Secondary batteries with high performance are essential in widespread use of modern portable devices such as cellular phones and laptop computers. High energy density, long cycle life, and safety are some of important requirements for secondary battery. To achieve such characteristics, a mixing proportion of electrolyte solution ingredients in the battery should be carefully chosen. In this paper, using statistical design of mixture experiments (DOME), we attempt to find an optimum condition of designing the secondary battery. DOME has a distinct feature in that the experimental region is represented by simplex, rather than hypercube, because the sum of blend proportions should be unity. Several designs based upon this point have been proposed for mixture experiments. Among them, an extreme vertices design is employed in this paper because there are a couple of blend constraints to be considered. In order to investigate how the mixing proportion interacts with other manufacturing factors, a fractional factorial design is also included across the extreme vertices design. As a result, we find that the blend proportion of solution ingredients has a significant effect on battery performances. By simultaneously optimizing two battery capacities, this paper proposes an optimum blend proportion according to process factor settings.

• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.571-578
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• 1997

This paper presents a method for designing a control system to stand upright inverted triangle. A linearized model is obtained form the nonlinear system by Taylor series expansion and a state controller is designed based on the model. After implementing the control system which is combined control law and estimator with reference input, experiments are carried out to stand upright inverted triangle at any angluar position.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2010년도 춘계학술대회
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• pp.123-128
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• 2010

This article investigates economic-statistical design of VSI(variable samling interval) charts considering Various Runs Rules. Most recent adaptive control charts are conplex designs. Actually It's not easy to operating control quality process. We propose a procedure for designing VSI Runs charts, based on Lorenzen and Vence's model. The optimal design parameters of the charts can be determined by minimizing the cost model. And computational experiments show that the VSI Runs Rules charts is superior to the FSSI Runs Rules charts in the economic-statistical characterisitics.

• 대한교통학회지
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• 제12권4호
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• pp.21-33
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• 1994

The grade is a very significant factor in designing the bikeways. It affects the cyclist's maneuverability as well as route selection. The objective of this paper is to provide the vertical length by grade for bikeway. Field experiments were conducted by primary school children and university students to collect and analyze bike's climbing capability by grade. Combined data suggests that the desirable vertical length is 360m for 3% grade, 220m for 4%, 160m for 5%, 120m for 6% and 90m for 7% grade.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2004년도 품질경영모델을 통한 가치 창출
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• pp.507-512
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• 2004

This research investigates economic-statistical characteristics of variable sampling size & interval(VSSI) X charts under two assignable causes. We propose the procedure for designing VSSI X charts, based on Lorenzen and Vance model. Computational experiments show that the VSSI X chart Is superior to the Shewhart X chart in the economic-statistical sense, even under two assignable causes

• Journal of the Korean Statistical Society
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• 제9권1호
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• pp.97-108
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• 1980

Variance components model appears often in designing experiments including time series data analysis. This paper is investigating the properties of the various procedures in estimating variance components for the two-way random model without interaction under normality. In this age of computer-oriented computations, MINQUE is found to be quite practicla because of the robustness with respect to the design configurations and parameters. Also adjusted AOV type estimation procedure is found to yield superior results over the unadjusted one.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.487-494
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• 2006

The ultimate capacities of a rubber bearing are defined by compressive stress, shear strain, and stabilized roster ing force. The experiments were conducted with parameters of shesr elasticity(G) and first shape factor(S1), second shape factor(S2) for rubber bearing. Considering with test results, the ultimate capacities were verified, and furthermore the influence of those parameters were clarified. Using test results stable deformation of rubber bearings for designing was proposed.

• 한국주조공학회지
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• 제14권6호
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• pp.576-589
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• 1994

Water modeling experiments and computer simulation for the predictions of defects of die castings are very important to produce high quality castings with less cost. The relation between the variable air vent system and the characteristics of the fluid flow in the die cavity is studied by using water modeling tests, which give ideas on reasonable designing of die cavity, vent arrangement and gating system. In order to test the water modeling, injection is done by using water containing NaCl. Flow behaviors in cavities are visualized by high speed camera and video tape recorder, and local filling time is measured with electrode sensors. Special attention is paid to the configuration of die cavity. Simulated results by computer are examined and compared with the results of water modeling experiments. There are close correlations between the simulated results and water modeling ones.