• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.3
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• pp.234-239
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• 2011

In this study, the heat transfer capability have been improved by using via-holes in FR4 PCB, when the LED lighting is designed to solve the thermal problem. The thermal resistance and junction temperature were measured by changing the dimension of FR4 PCB and size of via hole. As a result, when the dimension was increased initially, the thermal resistance and junction temperature was decreased rapidly, the ones was stabilized after the dimension of 200 $[mm^2]$. Also, the light output was improved up to maximum 17% by formation of via-hole and expansion of dimension in FR4 PCB. Therefore, the thermal resistance and junction temperature could be improved by expansion of PCB dimension and configuration of via-hole ability.

• Journal of Chest Surgery
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• v.27 no.8
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• pp.656-663
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• 1994

Evaluation of heart function is of importance in assessing the results of valvular heart surgery. Information on volume and functional change of heart chamber can be obtained by cardiac catheterization and echocardiography. We studied 41 patients with mitral stenosis[MS] and 23 patients with mitral regurgitation[MR] using M-mode echocardiography before and after mitral valve replacement[MVR] at Pusan Paik Hospital. Preoperative cardiac catheterization was available in 56 cases, and the results were obtained as follows. 1. In patients with MS, preoperative average LV end-diastolic dimension[EDD] and end-systolic dimension[ESD] were remained within normal range, but postoperative EDD and ESD were significantly decreased[P<0.01]. The preoperative and postoperative LV ejection fraction[EF] were remained within the normal range and no significant change[P>0.05]. The preoperative left atrial dimension[LAD] was enlarged considerably above normal[P<0.01], but was significantly decreased after surgery[P<0.001]. The preoperative LV posterior wall thickness[PWTh] was within normal range, and no significant change after surgery[P>0.05]. 2. In patients with MR, preoperative average end-diastolic dimension[EDD] and end-systolic dimension[ESD] were significantly greater than normal[P<005], but postoperative EDD and ESD were significantly decreased[P<0.01]. The preoperative LV ejection fraction[EF] and fractional shortening[FS] were within normal range, and no significant change after surgery[P>0.05].The preoperative left atrial dimension[LAD] was enlarged considerably above normal [P<0.01], but was significantly decreased after surgery[P<0.001].The preoperative LV posterior wall thickness[PWTh] was within normal range, and no significant change after surgery[P>0.05].

• Communications of the Korean Mathematical Society
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• v.18 no.2
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• pp.281-288
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• 2003

In this paper, we calculate the lower and upper bound of the correlation dimension([4], [6]) for a Cantor-like set([5])

• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.162-176
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• 2001

This study was covered with the analysis of five kinds of the middle school science text books(chemistry part) based on the oth curriculum. Particularly, inquiry activities part was analyzed by the three dimension framework which consists of inquiry content dimension, inquiry process dimension and inquiry context dimension and the results are as follows;1. In the analysis of the contents in the middle school science textbooks(chemistry part), the average number of total pages was 197.6. The illustration and picture were contained 0.66 in number per a page, and the average number of further readings was 5.8.2. In the analysis of the inquiry content dimension of inquiry activities, the total number of themes in five kinds of textbooks was 222. And the number of imquiry activities in five kinds of textbooks was siverse : A textbook had 51, B texbook 49, C textbook 37 and E textbook 35.3. For the analysis of inquiry process dimension. it follows in the order of 'interpreing data and formulating generalizations (42.4%)','observation and measuring (38.1%)','seeing a problem and seeking ways to solve it (7.8%)' and 'building, testing and revising the theoretical model(11.7%)'.4. As for the analysis of the inquiry context dimension, the scientific context occupied 94.2%, the individual context 0.4%, the social context 2.7% and the technical context 2.7%. It shows that the proportion of STS(Science-Technology-Society) related contents in inquiry activities was only 5.8%.

• Korean Journal of Cognitive Science
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• v.22 no.2
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• pp.103-121
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• 2011

This study investigated how spatial dimension information and dimensional consistency between learning and testing phase would influence the target search performance. The participants learned spatial layouts of Lego blocks shown in either two- (2D) or three-dimension (3D) and were tested with the rotated stimuli ($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, or $270^{\circ}$ from the initial view) in consistent or inconsistent dimension. Significantly better performance was observed when initial learning display appeared in 2D than in 3D. Particularly, the participants showed difficulties in flexible usage of spatial information presented in 3D especially if the dimensional information in the testing phase also was 3D and required mental rotation. The present study indicates that spatial map presented in 2D may be more useful than 3D in driving situations in which acquired spatial information from navigating device, such as GPS, and location of driver continuously changes.

• Bulletin of the Korean Mathematical Society
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• v.40 no.4
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• pp.613-631
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• 2003

The purpose of this paper is to study n-dimensional QR-submanifolds of (p - 1) QR-dimension in a quaternionic projective space $QP^{(n+p)/4}$ and especially to determine such submanifolds under the curvature conditions appeared in (5.1) and (5.2).

• Bulletin of the Korean Mathematical Society
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• v.38 no.3
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• pp.575-586
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• 2001

The purpose of this paper is to study n-dimensional CR-submanifolds of (n-1) CR-dimension immersed in a complex projective space $CP^{(n+p)/2}$, and especially to determine such submanifolds under some curvature conditions.

• Korean Journal of Mathematics
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• v.16 no.2
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• pp.157-163
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• 2008

Using informations of subsets of divergence points and the relation between members of spectral classes, we give another complete decomposition of spectral classes generated by lower(upper) local dimensions of a self-similar measure on a self-similar Cantor set with full information of their dimensions. We note that it is a complete refinement of the earlier complete decomposition of the spectral classes. Further we study the packing dimension of some uncountable union of distribution sets.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.2
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• pp.245-250
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• 2009

We consider a code function from the unit interval which has a generalized dyadic expansion into a coding space which has an associated ultra metric. The code function is not a bi-Lipschitz map but a dimension-preserving map in the sense that the Hausdorff and packing dimensions of any subset in the unit interval and its image under the code function coincide respectively.

• Bulletin of the Korean Mathematical Society
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• v.58 no.2
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• pp.497-505
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• 2021

Let R → S be a ring homomorphism. The relations of Gorenstein projective dimension with respect to a semidualizing module of homologically bounded complexes between U ⊗LR X and X are considered, where X is an R-complex and U is an S-complex. Some sufficient conditions are given under which the equality ${\mathcal{GP}}_{\tilde{C}}-pd_S(S{\otimes}{L \atop R}X)={\mathcal{GP}}_C-pd_R(X)$ holds. As an application it is shown that the Auslander-Buchsbaum formula holds for GC-projective dimension.