• Journal of the Korea Society for Simulation
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• v.3 no.2
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• pp.57-67
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• 1994

For many practical and industrial optimization problems where some or all of the system components are stochastic, the objective functions cannot be represented analytically. Therefore, modeling by computer simulation is one of the most effective means of studying such complex systems. In this paper, with discussion of simulation optimization techniques, a case study in machining process for application of simulation optimization is presented. Most of optimization techniques can be classified as single-or multiple-response techniques. The optimization of single-response category, these strategies are gradient based search methods, stochastic approximate method, response surface method, and heuristic search methods. In the multiple-response category, there are basically five distinct strategies for treating the responses and finding the optimum solution. These strategies are graphical method, direct search method, constrained optimization, unconstrained optimization, and goal programming methods. The choice of the procedure to employ in simulation optimization depends on the analyst and the problem to be solved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.755-761
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• 2003

Recently, the development of mobile devices demands information storage systems to use micro drive devices and cheap media. These should have several characteristics, for example, the subminiature of size, the robustness of shock, the minimum of cost and power consumption, and the removability of multiple applications. A conventional optical disk drive is more suitable for these specifications than the others. The optical storage system of the new generation to use a blue laser and a high numerical aperture (NA) is the perfect candidate for micro optical disk drives. In this paper, the micro actuator that can be applied to a micro optical disk drive is designed by response surface methodology to use a structural analysis and an electro-magnetic analysis. Based on above results, the coarse actuator and fine actuator are designed and improved from the point of view of the size and the power. Consequently, the designs of a micro actuator are proposed through these courses.

• Journal of computational fluids engineering
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• v.14 no.2
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• pp.25-31
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• 2009

Numerical optimization of rotor blade airfoils is performed with a response surface method for helicopter rotor. For the baseline airfoils, OA 312, OA 309, and OA 407 airfoils are selected and optimized to improve aerodynamic performance. Aerodynamic coefficients required for the response surface method are obtained by using Navier-Stokes solver with k-$\omega$ Shear Stress Transport turbulence model. An optimized airfoil has increased drag divergence Mach number. The present design optimization method can generate an optimized airfoil with multiple design constraints, whenever it is designed from different baseline airfoils at the same design condition.

• Korean Journal of Food Science and Technology
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• v.18 no.4
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• pp.259-263
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• 1986

The effect of ingredients on the hardness of ginseng jelly were studied by response surface methodology and observed by multiple regression equation $({R_A}^2=0.8660)$ and response surface contour. The hardness of ginseng jelly was directly influenced by the order of the contents of glucose > gelatin > sucrose > water > citric acid and it was also affected interactions of water and glucose.

• Educational Technology International
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• v.15 no.2
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• pp.117-141
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• 2014

This qualitative study investigated different interaction patterns in an online discussion. The data was collected from asynchronous discussion occurred in a graduate course. The data analysis methods include inductive analysis and mapping strategy. The results of the study suggest three layers of interaction: response sequences, interaction amongst participants, and concept map of messages. The visualization of response sequences enabled the researcher to discover complex and dynamic interaction patterns amongst participants. The many-to-many communication feature of online discussion does not always enable direct one-on-one interaction between two participants. Rather, one message contributed to multiple threads in the stream of conversation. In terms of interaction amongst participants, the interaction amongst participants, as indicated in the data, the messages also bind each participant and consequently a group(s) of participants together. It appears that the contribution of one message may not only enable a response to one participant, but also connect many participants to each other. The concept map of messages proposes that response sequences and interaction amongst participants can also be viewed between concepts within messages in the discussion. On the surface, the messages posted by individuals are linked by the system in a linear fashion as they are posted. However, the interaction extends to collaborative conversation amongst participants. Ultimately, a conceptual network of interrelated ideas including multiple perspectives is built in asynchronous discussion.

• Journal of Korean Society for Quality Management
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• v.48 no.4
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• pp.535-552
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• 2020

Purpose: The main theme of this study is to derive a specific quality loss function with multiple characteristics according to the same analytical structure as the single characteristic quality loss function of Taguchi. In other words, it presents an analytical framework for measuring quality costs that can be controlled in practice. Methods: This study followed the analytical methodology through geometric, linear algebraic, and statistical approaches Results: The function suggested by this study is as follows; $$L(x_1,x_2,{\cdots},x_t)={\sum\limits_{i=1}^{t}}k_i\{x_i+{\sum\limits_{j=1}^{t}}\({\rho}_{ij}{\frac{d_i}{d_j}}\)x_j\}x_i$$ Conclusion: This paper derived the quality loss function with multiple quality characteristics to expand the usefulness of the Taguchi quality loss function. The function derived in this paper would be more meaningful to estimate quality costs under the practical situation and general structure with multiple quality characteristics than the function by linear algebraic approach in response surface analysis.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.91-94
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• 2009

We propose advanced liquid crystal display (LCD) modes through surface modification using UV curable reactive mesogen (RM) mixed with alignment layers. The LC directors on the modified alignment layer are controlled and memorized by the polymerized RMs under an applied voltage. Using the method proposed here, we can improve the response time and viewing angle characteristics through surface controlled patterned vertical alignment (SC-PVA) mode and 8-domains PVA mode, respectively. Also, we found that the method can be applicable to fabricate multi-domain structures using multiple UV exposure as same as conventional UV alignment method.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.571-581
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• 2010

This study analyzed rainfall-runoff characteristics by deriving multiple impulse responses. The concept of competing impulse responses was used for deriving multiple impulse responses. Based on this concept, each response function derived competes to be selected for simulating the runoff measured. This concept of competing linear impulse responses was applied to four basins, Jeongseon, Yeongwol, Youngchoon and Chungju Dam. One to three impulse responses have been derived and compared each other considering basin characteristics. First, in case of deriving one linear impulse response, the peak flow of the impulse response was found to be increased according to their study basins area. In case of deriving two linear impulse response, the peak flow of the first impulse response and the duration of the second impulse response were increased according to their basin size. The case of deriving three impulse response showed similar characteristics of deriving two impulse responses. However, the peak flow of third impulse response was very small and lasted quite long time. Summarizing these results considering the basin characteristics, the first impulse response seems to be related with the surface runoff, the second impulse with the surface runoff and interflow, and the third impulse response with the interflow and base flow.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.143-146
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• 2003

A finite element based on the efficient higher order zig-zag theory with multiple delaminations Is developed to refine the predictions of frequency and mode shapes. Displacement field through the thickness are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field. The layer-dependent degrees of freedom of displacement fields are expressed in terms of reference primary degrees of freedom by applying interface continuity conditions including delaminated interfaces as well as free hounding surface conditions of transverse shear stresses. Thus the proposed theory is not only accurate but also efficient. This displacement field can systematically handle the number, shape, size, and locations of delaminations. Throught the dynamic version of variational approach, the dynamic equilibrium equations and variationally consistent boundary conditions are obtained. Through the natural frequency analysis and time response analysis of composite plate with multiple delaminations, the accuracy and efficiency of the present finite element are demonstrated. The present finite element is suitable in the predictions of the dynamic response of the thick composite plate with multiple delaminations.

• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.84-92
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• 1995

A method is proposed for the simultaneous optimization of several response functions that depend on the same set of controllable variables and are adequately represented by a response surface model (polynomial regression model) with the same degree and with constraint that the individual responses have the target values. First, the multiple responses data are checked for linear dependencies among the responses by eigenvalue analysis. Thus a set of responses with no linear functional relationships is used in developing a function that measures the distance estimated responses from the target values. We choose the optimal condition that minimizes this measure. Also, under the different degree of importance two step procedures are proposed.