• Proceedings of the KSME Conference
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• 2000.11a
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• pp.783-788
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• 2000

Hydroforming is a method for forming circular tubes. If this technology is to be applied economically, it is essential to have knowledge of the avoidance of failure cases as well as of the behavior of the tube in the tool under the compressive stress and forces that are exerted by the machine. A finite element simulation for manufacturing of lower arm from straight tubes, using the hydroforming method, was performed to investigate the effects of varying process parameters. Explicit method is used to simulate hydroforming in many cases, but that is not included flow rule. And then it needs simulation for implicit method. It was simulated by two methods, implicit and explicit, to compare the result of the hydroforming.

• Anxiety and mood
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• v.8 no.1
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• pp.3-8
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• 2012

Patients with panic disoder (PD) show recollection of their first panic attack, which resembles a trauma that is perceived as an unexpected frightening and subjectively life-threatening event. Information-processing models suggest that anxiety disorders may be characterized by a memory bias for threat-related information. This paper reviews the previous researches that investigated the implicit and/or explicit biases in patients with panic disorder. Among the 17 studies, which addressed the explicit memory bias in PD patients, 11 (64.7%) were found to be explicit memory bias in PD patients. In regards to the implicit memory bias, 4 out of 9 studies (44.4%) were found to support the memory bias. The result shows that evidence of explicit memory bias in PD patients was supported by a number of previous researches. However, evidence of implicit memory bias seems less robust, thus, needs further research for replication. Also, development of new paradigms and applications of various methods will be needed in further researches on memory bias in PD patients.

• Structural Engineering and Mechanics
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• v.85 no.5
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• pp.607-620
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• 2023

The classical optimal control (COC) method has been widely used for linear quadratic regulator (LQR) problems of structural control. However, the equation of motion of the structure is incorporated into the optimization model as the constraint condition for the LQR problem, which needs to be solved through the Riccati equation under certain assumptions. In this study, an explicit optimal control (EOC) method is proposed based on the explicit time-domain method (ETDM). By use of the explicit formulation of structural responses, the LQR problem with the constraint of equation of motion can be transformed into an unconstrained optimization problem, and therefore the control law can be derived directly without solving the Riccati equation. To further optimize the weighting parameters adopted in the control law using the gradient-based optimization algorithm, the sensitivities of structural responses and control forces with respect to the weighting parameters are derived analytically based on the explicit expressions of dynamic responses of the controlled structure. Two numerical examples are investigated to demonstrate the feasibility of the EOC method and the optimization scheme for weighting parameters involved in the control law.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.634-637
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• 2008

A large eddy simulation with an explicit filter on unstructured mesh is presented. The flow filed is semi-implicitly marched by a fractional step method. Spatial discretization of the solver is designed to guarantee the second order accuracy. An isotropic explicit filter is adopted for measuring the level of subgrid scale velocity fluctuation. The filter is linearity-preserving and has second order commutation error. The developed subgrid scale model is basically eddy viscosity model which depends on the explicitly filtered fields and needs no additional ad hoc wall treatment, such as van Driest damping function. For the validation, the flows in a channel and a pipe are calculated and compared to experimental data and numerical results in the literature.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.2
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• pp.157-165
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• 2016

To provide the baseline for pricing, this paper proposes pricing-by-rating (PBR) as pricing model at micro-foundations level that can work as the baseline for all pricing models as well as an assessment criterion of business model in all circumstances. It sets up firstly WTP (willingness to pay/purchase) model from explicit needs and develops PBR based on the ordinal scale of the difference between the WTP and the WTS (willingness to supply/sell) by comparing individually the corresponding element/component of a firm's actual marketing mix 4P with that of the best SPEC (solution, price indicator by WTP, encouragement, channel) as an ideal 4P a customer expects and also by comparing the interaction between the 4P and the best SPEC as a whole collectively. And through illustrations it shows its applicability to evaluating business model in practice and finally asserts that PBR works as the baseline for pricing policy and as a criterion of business model evaluation in any circumstances.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.106-109
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• 2006

A large eddy simulation with explicit filters on unstructured mesh is presented. Two explicit filters are adopted for reducing the aliasing error of the nonlinear convective term and measuring the level of subgrid scale velocity fluctuation, respectively. The developed subgrid scale model is basically eddy viscosity model which depends on the explicitly filtered fields and needs no additional ad hoc wall treatment such as van Driest damping function. As a validation problem, the flows around a sphere at several Reynolds numbers, including laminar and turbulent regimes, are calculated and compared to experimental data and numerical results in the literature.

• Transactions of Materials Processing
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• v.11 no.4
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• pp.302-311
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• 2002

A generalized numerical approach based on the finite element method to analysis and design of hydroforming process is proposed in this paper. The special attention is focused on comparison of an implicit and an explicit finite element method widely used for hydroforming simulation. Furthermore, in order to meet the increasing real needs for prediction of forming limit, a ductile fracture criterion combined with finite element method is introduced and then applied to hydroforming process of an automobile lower m Consequently, the numerical analysis and design for hydroforming process presented here will facilitate the development and application of the tube hydrofoniung process to a new level.

• Journal of computational fluids engineering
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• v.9 no.3
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• pp.26-38
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• 2004

A study has been made for the investigation of the robustness and convergence of various implicit operators of the LU-SGS scheme using linear stability analysis. It is shown that the behavior of the implicit operator is not determined by its own characteristics, but is determined relatively depending on the dissipative property of the explicit operator. It is also shown that, as the dissipation level of the implicit operator increases, the robustness of the scheme increases, but the convergence rate can be deteriorated due to the excessive dissipation. The numerical results demonstrate that the dissipation level of the impliict operator needs to be higher than that of the explicit operator for computing stiff problems.

• Korean Journal of Child Studies
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• v.34 no.6
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• pp.139-158
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• 2013

Karmiloff-Smith was first to propose the 'Representational Redescription model'. It describes a process through which children elaborate their knowledge from the unconscious and implicit levels to the conscious and explicit levels. The model also assumes that children in perfectly explicit levels are able to express their own representation of knowledge verbally. This study was conducted to investigate Karmiloff-Smith's Representational Redescription(RR) model(1990, 1992, 1999) within the drawing domain. Additionally, how verbalization training influences children's development of representational redescription in drawing were also examined. First, 331 children (4- to 6-year-olds and an older comparison group of 7- to 9-year-olds) were asked to create six drawings of both familiar and novel topics. From these drawings, children were measured for procedural rigidity and developmental differences. Thereafter 80 5-year-olds children who were not able to manipulate their drawings with flexibility were selected. They were divided into an experimental group and two control groups. A group of verbalization training was given a session using 5 tasks. Compared to the control groups, children who practiced verbalization in the training group showed more advanced levels of representation than their previous levels in the pretest. The results were interpreted as meaning that verbalization is likely to facilitate children's reorganization of implicit knowledge within the drawing domain and to transfer this toward explicit forms. Further research needs to pay more attention to the educational applications of learning processes based on representational redescription.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.76-83
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• 2006

Each tire has a critical speed at which a standing wave phenomenon occurs along the circumferential direction. If the standing waves are formed, the tire temperature is rapidly increased and it leads to tire failure eventually. As the formation of the standing waves is closely related to the tire stiffness, the effect of the tread pattern needs to be studied numerically. The standing wave phenomenon of a tire model with tread pattern is predicted by an explicit finite element method. The critical speed of the tire with tread pattern is in a good agreement with the experiment and is $15{\sim}20\;km/h$ lower than that of the tire without tread pattern. The effects of the inflation pressure and the vertical load on the critical speed are also investigated by using the tire model with tread pattern.