• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.3
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• pp.212-217
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• 2012

The cooling of data centers has emerged as a significant challenge as the density of IT equipment increased. With the rapid increasing of heat load and cooling system, predictions for electronics power trends have been closely watched. A data center power density projection is needed so that IT organizations can develop data centers with adequate cooling for reasonable lifetimes. This paper will discuss the need for something more than processor and equipment power trend projections which have overestimated the required infrastructure for customers. This projection will use data from a survey of actual enterprise data centers and the ASHRAE projections to formulate a data center server heat load trend projection.

• Communications for Statistical Applications and Methods
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• v.26 no.4
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• pp.337-346
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• 2019

This paper discusses a method for obtaining nonnegative estimates for variance components in a random effects model. A variance component should be positive by definition. Nevertheless, estimates of variance components are sometimes given as negative values, which is not desirable. The proposed method is based on two basic ideas. One is the identification of the orthogonal vector subspaces according to factors and the other is to ascertain the projection in each orthogonal vector subspace. Hence, an observation vector can be denoted by the sum of projections. The method suggested here always produces nonnegative estimates using projections. Hartley's synthesis is used for the calculation of expected values of quadratic forms. It also discusses how to set up a residual model for each projection.

• Communications of the Korean Mathematical Society
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• v.36 no.2
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• pp.327-342
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• 2021

We consider a generalization of the L^q-spectrum with respect to two Borel probability measures on ℝⁿ having the same compact support, and also study their behavior under orthogonal projections of measures onto an m-dimensional subspace. In particular, we try to improve the main result of Bahroun and Bhouri [4]. In addition, we are interested in studying the behavior of the generalized lower and upper L^q-spectrum with respect to two measures on "sliced" measures in an (n - m)-dimensional linear subspace. The results in this article establish relations with the L^q-spectrum with respect to two Borel probability measures and its projections and generalize some well-known results.

• Bulletin of the Korean Mathematical Society
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• v.59 no.5
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• pp.1215-1235
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• 2022

In this paper we study Szegö kernel projections for Hardy spaces in quaternionic Clifford analysis. At first we introduce the matrix Szegö projection operator for the Hardy space of quaternionic Hermitean monogenic functions by the characterization of the matrix Hilbert transform in the quaternionic Clifford analysis. Then we establish the Kerzman-Stein formula which closely connects the matrix Szegö projection operator with the Hardy projection operator onto the Hardy space, and we get the matrix Szegö projection operator in terms of the Hardy projection operator and its adjoint. At last, we construct the explicit matrix Szegö kernel function for the Hardy space on the sphere as an example, and get the solution to a Diriclet boundary value problem for matrix functions.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.7
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• pp.129-140
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• 1994

In this paper we investigate the hardware implementation of block matching algorithms (BMAs) for moving sequences. Using systolic arrays we propose a hardware architecture of a two-stage BMA using integral projections which reduces greatly computational complexity with its performance comparable to that of the full search (FS). Proposed hardware architecture is faster than hardware architecture of the FS by 2~15 times. For realization of the FS and two stage BMA modeling and simulation results using SPW and VHDL are also shown.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2009.05a
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• pp.153-159
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• 2009

The purpose of this paper is to suggest the problems of basic population data(1960-2005) and the data(2006-2050) of population projections reported by Korean National Statistical Office in November 2006. The errors on the basic population data can be easily checked by using the graphical analysis and the method of linear regression analysis. It is necessary to revise the population projections reported by Korean National Statistical Office.

• Journal of radiological science and technology
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• v.15 no.2
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• pp.11-15
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• 1992

For improving the image quality in case of neck Lateral projections, the Al compensation filter were used and conclusion that, it could be got the high image quality able to observe the shadow of cervical spine, hyoid bone, trachea, soft tissue simultaneously.

• Korean Journal of Mathematics
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• v.24 no.1
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• pp.65-70
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• 2016

J. G. Stampfli proved that if a bounded linear operator T on a Hilbert space ${\mathfrak{H}}$ satisfies ($G_1$) property, then the Riesz projection $P_{\lambda}$ associated with ${\lambda}{\in}iso{\sigma}$(T) is self-adjoint and $P_{\lambda}{\mathfrak{H}}=(T-{\lambda})^{-1}(0)=(T^*-{\bar{\lambda}})^{-1}(0)$. In this note we show that Stampfli''s result is generalized to an nilpotent extension of an operator having ($G_1$) property.

• Journal of the Korean Data and Information Science Society
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• v.18 no.2
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• pp.419-427
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• 2007

Recently, Korean National Statistical Office submits the results of population projections for Korea from 1960 to 2050 year. The purpose of this paper is to suggest the reasonable assumptions for the survey of population, and then to detect the errors of the surveyed population (1960-2005) on Korean Information Statistical System.

• Communications of the Korean Mathematical Society
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• v.25 no.4
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• pp.547-556
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• 2010

In this paper, we present the reprentation of all operators B which are Drazin invertible and sharing the spectral projections at 0 with a given Drazin invertible operator A. Meanwhile, some related results for EP operators with closed range are obtained.