• Research in Mathematical Education
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• v.1 no.2
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• pp.163-181
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• 1997

The paper deals with some aspects of early childhood geometry in the Czech Republic. Children's first geometrical experiences come from real life. In our opinion, there exist four types of geometrical experience which can be called the partition of space, the filling of space motion in space and the dimension of space. We distinguish three levels of the mathematical learning process: a spontaneous level, an operational level and a theoretical level.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.939-941
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• 2005

This research presents a 3D multi-objective approach regarding both magnetic and thermal characteristics associated with design of C-core actuator. The adjoint variable topology sensitivity equations are derived using the continuum method for three dimension. The sensitivity is verified using the Finite Difference Method(FDM). Convection interpolation function is proposed for density method of topologies such that convection term can be taken into consideration for practical design in the process of the optimization.

• Bulletin of the Korean Chemical Society
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• v.8 no.2
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• pp.83-88
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• 1987

The Smoluchowski equations with a linear and a parabolic potentials in one-dimensional case are solved for the reflecting boundary condition. Analytic expressions for the long-time behaviors of the remaining probabilities are obtained. These results, together with the previous result for a step potential, show the dependence of the desorption process on the form of potential. The effect of the radiation boundary condition is also investigated for three types of potentials.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.226-233
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• 1999

The crash behaviour analysis of KHST is studied. KHST is modeled in 3D using the multibody dynamic analysis program DADS. The forward and side crash behaviour is predicted by tile dynamic analysis model and compared with those of another dynamic model. This study shot's that it is possible to predict tile crash behaviour of the trains in three dimension.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1128-1131
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• 2004

SFF(solid freeform fabrication) is another name of RP(rapid prototyping). The SFFS for office type wishes to develop system that can produce small object such as hand phone, cup, accessory etc. with high speed, and also intend suitable system in office environment by compact design, and buy easily by inexpensive price. As can manufacture high speed in existent SFF process technology, representative process that have competitive power in price is 3DP (three dimensional printing) technology. The 3DP technology is way to have general two dimensional printing technology and prints to three dimension, is technology that make three-dimensional solid freeform that want binder doing jetting selectively on powder through printer head. We designed and manufactured SFFS for office based on 3DP process technology design and manufactured, and composed head system so that use 3 printer heads at the same time to improve the fabrication speed of system. We used printer head of INCJET company and cartridge used HP45 series model who can buy easily in general city. And we directly fabricated three dimensional solid freeform using developed SFFS for office type.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.3
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• pp.68-75
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• 2008

The three-dimensional structure of detonation wave propagating in a circular tube was investigated using a parallel computational code developed previously. A series of parametric study for a circular tube of a fixed diameter gave the formation mechanism of the detonation cell structures depending on pre-exponential factor, k. The unsteady results in three-dimension showed the mechanisms of two, three and four cell mode of detonation wave front structures. The detonation cell number was increased but cell width and length were decreased with increased pre-exponential factor k. In the all multi-cell mode, the detonation wave structure and smoked-foil records on the wall are made by the moving of transverse waves. The detonation wave front structures have the regular polygon and windmill shapes periodically.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.240-240
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• 2015

As Simpson et al. (1990) emphasized the importance of the straining process in the stratification and mixing in the estuarine circulation process, various researches have investigated on the relative contribution of each process to the overall potential energy anomaly dynamics. However, many numerical works have done only for two dimensional modeling along channel or the short distance cross sectional three dimensional simulations as Burchard et al. (2008) and the estuarine channel was not simulated so far. But, in the study on the physics of shallow coastal seas, spatial dimension in the three dimensional way affects significantly on results of a particular numerical model. Therefore, the comparison of two and three dimensional models is important to understand the real physics of mixing and stratification in an estuary. Also, as Geyer and MacCready (2013) pointed out that the lateral process seems to be important in determining the periodic stratifications, to study such process the three dimensional modeling must be required. The present study uses a numerical model to show the signification roles of each term of the time-dependent dynamic equation for the potential energy anomaly (PEA) in controlling along and lateral channel flows and different stratification structures. Moreover, we present the relationships between the ${\Phi}$-advection, the depth mean straining, vertical mixing and vertical advection can explain well how water level, salinity distribution and across velocity 2D model are slightly different from 3D.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.1
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• pp.13-22
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• 2001

This paper presents three dimensional structure of RF packages and the improvement effect of its electrical characteristics when implementing RF transceivers. We divided RF modules into several subunits following each subunit function based on the partitioning algorithm which suggests a method of three dimension stacking interconnection, PAA(pad area array) interconnection and stacking of three dimensional RF package structures. 224MHz ITS(Intelligent Transportation System) RF module subdivided into subunits of functional blocks of a receiver(RX), a transmitter(TX), a phase locked loop(PLL) and power(PWR) unit, simultaneously meeting the requirements of impedance characteristic and system stability. Each sub­functional unit has its own frequency region of 224MHz, 21.4MHz, and 450KHz~DC. The signal gain of receiver and transmitter unit showed 18.9㏈, 23.9㏈. PLL and PWR modules also provided stable phase locking, constant voltages which agree with design specifications and maximize their characteristics. The RF module of three dimension stacking structure showed $48cm^3$, 76.9％ reduction in volume and 4.8cm, 28.4％ in net length, 41.8$^{\circ}C$, 37% in maximum operating temperature, respectively. We have found that three dimensional PAA package structure is able to produce high speed, high density, low power characteristics and to improve its functional characteristics by subdividing RF modules according to the subunit function and the operating frequency, and the features of physical volume, electrical characteristics, and thermal conditions compared to two dimensional RF circuit modules.

• Journal of the Korean Home Economics Association
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• v.41 no.10 s.188
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• pp.149-171
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• 2003

This study was carried out as a basic fundamental research to propose a theoretical framework for Home Economics curriculum. This research employed the Delphi Method to reach a consensus with the experts in each related educational field of study for putting forth a newly proposed theoretical framework of a Home Economics curriculum. The finally proposed theoretical framework will definitely play a crucial role in establishing a standard framework for educational goals and curriculum content for Home Economics curriculum since it is put forth with a strong agreement from a high proportion of the expert groups. Results on the nature and characteristics of, structural framework of curriculum contents, and literacy through Home Economics were drawn from the 3-round Delphi survey: 1. Home economics has a liberal and practical-critical nature and it promotes enhancement of quality of life through a practical problem-solving process in maintaining family life. 2. The structural framework of the home economics curriculum contents is organized with three-dimensional components of content area (dimension 1), process area (dimension 2), focus of organizing content (dimension 3). 3. One's empowering capability through home economics education is proposed: inquiring knowledge and understanding phenomena for future society, solving practical problems in family life, developing higher order thinking skill, cultivating a positive attitude and a values system toward life.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.1
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• pp.1-9
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• 2011

The objective of this paper is to improve the accuracy of the 3D geopositioning extracted from Rational Polynomial Coefficient(RPC) provide in the KOMPSAT-2 metadata files. In this paper, we developed the algorithm to adjust a RFM(Rational Functional Model), and could improve the accuracy of a RFM with this algorithm. Furthermore, when a RFM was adjusted with this algorithm, the effects of the number of GCPs on the accuracy of the adjusted RFM was tested. For accuracy assessment using adjusted RFM, 9 ground control points(GCPs) and 24 check points could be used. Results indicated that the root mean squared errors(RMSEs) of horizontal residual errors calculated 24 check points were 2.20(m). The achieved accuracy of three dimensional object-point determination was 1.72(m) in the X-dimension and 1.37(m) in the Y-dimension and 2.20(m) in the Z-dimension.