• Research in Mathematical Education
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• v.11 no.1
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• pp.1-31
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• 2007

Recent research has documented that there is a close relationship between problem posing and problem solving in arithmetic. However, most studies investigated the relationship between problem posing and problem solving only by means of standard problem situations. In order to overcome that shortcoming, a pilot study with Chinese fourth-graders was done to investigate this relationship using a non-standard, realistic problem situation. The results revealed a significant positive relationship between students' problem posing and solving abilities. Based on that pilot study, a more extensive and systematic ascertaining study was carried out to confirm the observed relationship between problem posing and problem solving among Chinese elementary school children. Results confirmed that there was indeed a close relationship between both skills.

• IE interfaces
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• v.24 no.4
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• pp.341-350
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• 2011

This paper considers a problem of locating both distribution centers and retailers in a zone-dependent two-level distribution network where either a distribution center or a retailer should be located in each zone. Customer demands of each zone should be satisfied directly from either its own distribution center or its own retailer being supplied from a distribution center of another zone. The objective of the proposed problem is to minimize total cost being composed of distribution center/retailer setup costs and transportation costs. In the analysis, the problem is proved to be NP-hard, so that a branch-and-bound algorithm is derived for the problem. Numerical experiments show that the proposed branch-and-bound algorithm provides the optimal solution efficiently for some small problems.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.553-556
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• 2008

We hereby report novel driving scheme to eliminate effect of "residual" image sticking (RRI) problem which arises due to hysteresis problem in Thin Film Transistor (TFT) in AMOLED Displays. The driving scheme applies "black" voltage after every data voltage period in order to drive AMOLED in uni-direction. The system can be easily implemented with 120 Hz driving scheme which is well matured in AMLCD industries. Our analyses show systematic evaluation of the problem and thereby solving it by simple methods which will be significantly effective of driving OLED towards mass manufacturing stage.

• Korean Journal of Mathematics
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• v.6 no.2
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• pp.173-181
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• 1998

The local behaviors of the Hopf bifurcation in the free boundary problem satisfying the zero flux boundary condition was examined in [3]. In this paper, we shall examine the global behaviors for this problem and shall apply the center-index theory to show the globality.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.104-105
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• 1998

To minimize the Y2K (year 2000) date aware problem of medical devices, we are developing a database that keeps the data such as equipment type, specification, serial number, model number, acquisition date, vendor, manufacturer of the device as well as the names of departments that installed and that is currently responsible for the management of the medical device. The database also keeps the information as to whether the device awares the date, whether it is affected by the Y2K problem or not, how to solve the problem, reference home page address, and so on. The data was collected via internet search of the FDA web site and related of manufacturers homepages. To manage the Y2K problem effectively, the database should be updated regularly to include recent information.

• Journal of the Korean Mathematical Society
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• v.34 no.2
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• pp.395-405
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• 1997

A globality of the Hopf bifurcation in a free boundary problem for a parabolic partial differential equation is investigated in this paper. We shall examine the global behavior of the Hopf critical eigenvalues and and apply the center-index theory to show the globality.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1314-1317
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• 2006

The problem of the conflict between eye convergence and accommodation can be induced at Stereoscopic or multi-view 3D display system using binocular disparity. A multi-focus 3D display system was developed, which can solve the problem. LEDs are used instead of galvano scanner and laser to avoid mechanical moving part at the 3D display system.

• Korean Journal of Child Studies
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• v.35 no.1
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• pp.95-117
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• 2014

The study was performed at a childcare center based play therapy to help ameliorate the problems of infants in the borderline, self-concept, social interaction, infant's response changes observed during play therapy. The subjects of this study consisted of twenty eight infants between the ages of 4 to 5 years who exhibited behavior problems. All subjects were located in the Seoul. The play therapists were sent to the child care center, and conducted 16 sessions of play therapy to infants exhibiting problem behaviors. In summary, the results indicated the following. First, childcare center based play therapy was effective in improving infants' behavior problems in the borderline areas outlined above. Second, childcare center based play therapy had a positive effect on the self-concept of infants. Third, childcare center based play therapy had a positive effect on the social interaction among the infants. Finally, there was significant difference in the responses of infants during childcare center based play therapy.

• Bulletin of the Korean Mathematical Society
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• v.54 no.2
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• pp.647-654
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• 2017

Duality methods based on modified Lagrangian functional for solving a model crack problem is considered. Without additional assumptions of regularity of the solution of an initial problem duality ratio is established for initial and dual problem.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1190-1195
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• 2003

In this paper, it is shown how a robot with n passive trailers can be controlled in backward direction. When driving backward direction, a kinematic model of the system is represented highly nonlinear equations. The problem is formulated as a trajectory following problem, rather than control of independent generalized coordinates. Also, the state and input saturation problems are formulated as a trajectory generation problem. The trajectory is traced by a rear hinge point of the last trailer, and reference trajectories include line segments, circular shapes and rectangular turns. Experimental verifications were carried out with the PSR-2(public service robot $2^{nd}$ version) with three passive trailers. Experimental result showed that the backward motion control can be successfully carried out using the proposed control scheme.