• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.445-446
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• 2012

• Computational Structural Engineering
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• v.28 no.2
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• pp.58-63
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• 2015

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6C
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• pp.429-437
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• 2008

Multiple-input multiple-output (MIMO) techniques can be used for the spectral efficiency enhancement of the cellular systems, which can be categorized into spatial multiplexing (SM) and spatial diversity schemes. MIMO systems suffer a severe performance degradation due to the intercell interference from the adjacent cells as the mobile terminal moves toward the cell boundary. Therefore for the spectral efficiency enhancement, an appropriate transmission scheme for the given channel environment and reception scheme which can mitigate the intercell interference are required. In this paper, we propose an adaptive signal transmission/reception scheme for the spectral efficiency improvement of $M_R{\times}M_T$ MIMO systems, present the decision criteria for the adaptive operation of the proposed scheme, and demonstrate the performance gain. The proposed scheme performs adaptive transmission using spatial multiplexing and spatial diversity, and adaptive reception using maximal ratio combining (MRC) and intercell spatial demultiplexing (ISD) when the spatial diversity transmission is used at the transmitter. Spatial multiplexing/demultiplexing is performed at the high signal-to-interference ratio (SIR) range, and the transmit diversity in conjunction with the adaptive reception uses either conventional MRC or ISD which can mitigate the $M_R-1$ interference signals, based on the mobile location. For the performance evaluation of the proposed adaptive scheme, the probability density function (pdf) of the effective SIR for the transmission/reception methods in consideration are derived for $M_R{\times}M_T$ MIMO systems. Using the results, the average effective SIR and spectral efficiency are presented and compared with simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2106-2115
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• 1994

As a pre processing for an edge detection process. edge preserving smoothing algorithm is proposed. For this purpose we used the interpolation method using B-spline basis function and scaling of digital images. By approximation of continuous function from descrete data using B-spline basis function. undetermined data between two sample can be computed. so that they smooth the surfaces of objects. Some edges having mainly low frequency components are detected using down scaling of the images. Edge maps from proposed pre processed images are hardly affected by the varying space constants($\sigma$) and threshold values used in detecting zero-crossing.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.1
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• pp.38-43
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• 1993

A Hybrid Finite Element Method(HFEM) is applied to solve the electrormagnetic scattering from multi-layered dielectric cylinders. An unbounde region is divided into local boundary regions where a practical differential equation solution is obtained, with the remaining unbounded region represented by a boundary integral equation. If sources, media inhomogeneities, and anisotropies are local, a surgace may be defined to enclose them. Therefore the integral region so defined is bounded, and differential techniques may be used there. Also, in the re- maining unbounded region a boundary integral equation may be formulated using only a simple free - space green's function. Therefore, The local boundary is represented by a boundary - value problem with boundary conditions and solved by the finite element method. The advantage of the proposed method is simple and efficient in the work of electromagnetic scattering. The validity of the results have been verified by comparing results of other method(boundary element method). Examples has been presented to calculate the scattered fields of lossy dielectric cylinders of arbitray cross section.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.4
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• pp.53-60
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• 2009

Recently, the Korean government has amended the "National Territory Planning Act" by adding criteria to designate the Impact Fee Zone on the basis of the population increase rate. Taking the Dongtan Newtown in Hwasung City as the case, the study first tries to apply a grid analysis method to figure out the cells that exceed the legal population increase rate criteria. Then, the study, for rather a practical purpose, introduces a scenario analysis that tries to envelope the cells into a spatially contiguous groups based on their degrees of stepwise adjacency by cell buffer formation. By overlapping the selected cell groups chosen by such stepwise scenarios over the actual zoning map of land-uses for the vicinity, it seems clear that the chosen areas rationally coincide with those residential blocks and commercial areas with the high population density in the Newtown.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.4
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• pp.121-125
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• 2009

The Public Noticed Land Price system was developed in order to establish a practical and consistent land price information system, where land prices are appraised and publicly noticed according to the Law Governing the Public Notice of Real Estate Prices and Appraisals.The appraisal process for evaluating and appraising the public noticed land price in conducted in phases, where the nation's land is divided into human and spatial portions according to administrative districts. Depending on the subjective judgement of the appraiser, it is therefore possible for discrepancies to occur in land prices for lots near the boundaries of administrative districts. There is the computerized support system to maintain the public noticed land prices balance between the boundaries of cities, counties, and districts (the units in which evaluation and appraisal are conducted to determine public noticed land prices). But, due to that system is divided into attribute and spatial data information, it is possible for discrepancies to occur in land prices for lots near the boundaries of administrative districts. The purpose of this study to suggest the reasonable methods on discrepancies in public noticed land prices through spatial analysis using GIS.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.36 no.2
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• pp.70-79
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• 2024

In this study, we introduce a linear spectral method capable of simulating wave generation and transformation caused by a moving bottom in a 3-dimensional space. The governing equations are linear dynamic free-surface boundary conditions and linear kinematic free-surface boundary conditions, which are solved in Fourier space. Solved velocity potential and free-surface displacement should satisfy continuity equation and kinematic bottom boundary condition. For numerical analysis, a 4th order Runge-Kutta method was utilized to analyze the time integral. The results obtained in Fourier space can be converted into velocity potential and free-surface displacement in a real space using inverse Fourier transform. Regular waves generated by various types of moving bottoms were simulated with the linear spectral method. Additionally, obliquely generated regular waves using specified bottom movements were simulated. The results obtained from the spectral method were compared to analytical solutions, showing good agreement between the two.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2395-2406
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• 1992

Laminar natural convection heat transfer from a hot body in a square enclosure has been studied for various center positions of a hot body at Grashof number Gr=1.5$\times$10／sup 5／, Prandtl number Pr=0.71 and dimensionless thermal conductivity K／sub s／／K／sub f／= 14710. In case of vertical cold walls, the natural convection at the dimensionless center position of a hot body, X／sub c／Y／sub c／=0.2, 0.5 shows the most strong and at X／sub c／, Y／sub c／=0.5, 0.8 the most weak. In case of horizontal cold walls, the natural convection at the dimensionless center position of a hot body ; X／sub c／ Y／sub c／=0.5, 0.2 shows the most strong and at X／sub c／, Y／sub c／=0.2, 0.5 the most weak.

• Korean Institute of Interior Design Journal
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• v.18 no.3
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• pp.84-92
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• 2009

Sociological, technical, and organizational changes have affected the culture of business in many ways. These changes are now encouraging new concepts in the workplace environment such as emotional approaches for a more creative and humanistic workplace let alone enhancing image of the company. The aim of this study is to understand current situations of common office areas and serve as a stepping stone for designing more creative and stimulating work environments. The study first examines concepts of new office designs in our modem society, then defines categories such as territorial fuzziness, eco-friendly, fun and play. Secondly, by using content analysis as research tool the researchers have investigated how the conceptual categories and detailed design presentation methods are shown in workplace designs in Korea. Scope of study is limited to 39 office design projects from 2002-2008 presented in the Korean monthly magazine 'Interiors'. As results. territorial fuzziness was found to be most popular method while play the least. For application wise, meeting rooms, rest area and hallways were places where these concepts appear the most. Even though, these new approaches in office designs can be found in our domestic offices, still more experimental and active approach seems to be needed.