• 한국멀티미디어학회논문지
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• 제21권11호
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• pp.1279-1287
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• 2018

In this paper, a new type of color coordinate conversion is proposed as modified CIEXYZ from RGB to compress the color gamut. The proposed segmentation includes principal component analysis for the optimal projection of a feature vector into a one-dimensional feature. The final step adopted for lip segmentation is Otsu's threshold for a two-class problem. The performance of the proposed method was better than that of conventional methods, especially for the chromatic feature.

• 한국환경복원기술학회지
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• 제15권3호
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• pp.55-66
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• 2012

This study was carried out to investigate vegetation of Rhododendron mucronulatum habitat in Mt. Biseul to recommend basic information for synecological characteristics and management methods. The survey was carried out from May to July, 2011 and totally 46 vegetation data including 42 families 93 genera 108 species 16 varieties and 5 forma were collected and analyzed. Among the investigated 129 taxa, the numbers of rare plant resources were summarized as 19 taxa; The rare plants designated by Korea Forest Service, the specific plants by floristic region and the endemic plants were listed as 3 taxa, 15 taxa and 4 taxa, respectively. Rhododendron mucronulatum habitat of Mt. Biseul was classified into 3 plant communities (Carex lanceolata-Rhododendron mucronulatum community, Potentilla dickinsii-Selaginella rossii community, Carex lanceolata-Quercus mongolica community). Carex lanceolata-Rhododendron mucronulatum community was subdivided into Tripterygium regelii subunit and Miscanthus sinensis for. purpurascens subunit by human interference degree. And synecology, syndynamics, synchorology of these plant communities were identified, and Site-species ordination analysis by Principal Coordinate Analysis (PCoA) reflected that human impact, soil moisture condition were main ecological factors determining the distribution pattern of classified plant communities. Therefore these plant communities correspond to quite distinctive 4 habitat types : unstable-dry type=Miscanthus sinensis for. purpurascens subunit, unstable-moderate type=Tripterygium regelii subunit, stable-dry type=Potentilla dickinsii-Selaginella rossii community, stable-moderate type=Carex lanceolata-Quercus mongolica community. Finally, through the vegetational diagnosis, proper management methods such as a limit on the access of visitors, planting of native woody plants after removing unwanted vines or grass were suggested.

• ETRI Journal
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• 제37권3호
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• pp.491-501
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• 2015

Spectrum sensing is an elementary function in cognitive radio designed to monitor the existence of a primary user (PU). To achieve a high rate of detection, most techniques rely on knowledge of prior spectrum patterns, with a trade-off between high computational complexity and long sensing time. On the other hand, blind techniques ignore pattern matching processes to reduce processing time, but their accuracy degrades greatly at low signal-to-noise ratios. To achieve both a high rate of detection and short sensing time, we propose fast spectrum sensing with coordinate system (FSC) - a novel technique that decomposes a spectrum with high complexity into a new coordinate system of salient features and that uses these features in its PU detection process. Not only is the space of a buffer that is used to store information about a PU reduced, but also the sensing process is fast. The performance of FSC is evaluated according to its accuracy and sensing time against six other well-known conventional techniques through a wireless microphone signal based on the IEEE 802.22 standard. FSC gives the best performance overall.

• Structural Engineering and Mechanics
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• 제35권2호
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• pp.141-173
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• 2010

In this paper a boundary element method is developed for the general flexural-torsional buckling analysis of Timoshenko beams of arbitrarily shaped cross section. The beam is subjected to a compressive centrally applied concentrated axial load together with arbitrarily axial, transverse and torsional distributed loading, while its edges are restrained by the most general linear boundary conditions. The resulting boundary value problem, described by three coupled ordinary differential equations, is solved employing a boundary integral equation approach. All basic equations are formulated with respect to the principal shear axes coordinate system, which does not coincide with the principal bending one in a nonsymmetric cross section. To account for shear deformations, the concept of shear deformation coefficients is used. Six coupled boundary value problems are formulated with respect to the transverse displacements, to the angle of twist, to the primary warping function and to two stress functions and solved using the Analog Equation Method, a BEM based method. Several beams are analysed to illustrate the method and demonstrate its efficiency and wherever possible its accuracy. The range of applicability of the thin-walled theory and the significant influence of the boundary conditions and the shear deformation effect on the buckling load are investigated through examples with great practical interest.

• 산업기술연구
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• 제25권B호
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• pp.89-97
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• 2005

Application of proper orthogonal decomposition (POD) and continuous wavelet transform (CWT) is introduced to study wind speed and building roof pressures of flow separation region. In this study, a detailed analysis of the approach wind flow, wind-induced building pressure and the relation between the two fields was carried out using the POD technique and CWT analysis. The results show potential of the application of POD and CWT in characterization of spatio-temporal and spectral properties of the approach wind and its induced dynamic pressure events. Some of findings resulting from the application of this analysis can be summarized as follows: (1) The POD first principal coordinate of the roof pressure in the separated shear layer is closely correlated with the longitudinal component of oncoming flow. (2) The CWT analysis suggests that the extreme peak pressure in the separated shear layer is due to condensed large-scale eddy motions.

• 한국해양공학회지
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• 제33권3호
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• pp.252-258
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• 2019

In this paper, the time history of the surface elevation measured at the Draupner platform in the North Sea in 1995 is used to examine the statistical characteristics of the wave data. The wave statistics for 48 surface measurements, which contain three freak wave occurrences, are summarized. The quartiles, boxplots, correlations, and pair plots of 15 variables, along with the abnormality index, are presented. The kurtosis and skewness of the surface elevation are two variables that are highly correlated with the abnormality index, which defines freak waves. Principal coordinate analysis showed that the direction of the changes in the abnormality index agreed with the changes in the kurtosis and skewness. In addition, various wave heights, except the maximum wave height, showed a similar direction for the height changes, and various wave periods showed a similar direction for the period changes. Based on the correlations and PCA analysis, the kurtosis and skewness of the surface profiles are the two most important variables to predict the abnormality index.

• 분석과학
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• 제17권3호
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• pp.217-224
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• 2004

소형의 이온선택성 전극을 흐름계 어레이로 구성하여 전자혀 시스템을 제작하였다. 제작된 전자혀 시스템에 음용수 및 알코올성 음료를 저 농도의 완충용액 (0.005 M Tris-$H_2SO_4$ pH 7.2)에 묽힌 후 9개의 전극이 장착된 흐름계에 흘려 보내어 전위차를 측정하였다. 얻어진 자료는 주성분 분석 (principal component analysis; PCA)을 통하여 식음료의 맛을 평가할 수 있도록 2차원 및 3차원 좌표계에 표시하였다. 본 연구에서 제작한 전자혀 시스템은 식품의 생산공정관리의 목적으로 또는 시중에서 구할 수 있는 식음료 맛의 변화 추이를 구분해 내는 목적으로 유용하게 사용될 수 있다.

• 전기화학회지
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• 제7권4호
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• pp.206-210
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• 2004

금속산화물 $(TiO_2,\;RuO_2,\;PbO_2,\;Ni(OH)_2)$과 Prussian blue (PB)를 각각 탄소반죽에 혼합한 후 스크린 프린팅 기법으로 6종의 탄소반죽 전극들을 제작하였다. 제작된 탄소반죽 전극들로 전자혀 시스템을 제작하여 다양한 음료수와 식품에 대한 감응을 0.1M carbonate buffer, pH 9.6완충 용액에 묽힌 후 대시간전류법의 방법으로 측정하였다 얻어진 자료를 주성분 분석법 (principal component analysis; PCA)으로 처리한 후 식음료의 맛을 평가할 수 있도록 2차원 좌표계에 표시하였으며, 그 결과 본 실험에서 제작한 시스템 및 분석법은 다양한 식음료의 종류를 뚜렷이 구분해 낼 수 있음을 확인하였다.

• Genomics & Informatics
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• 제6권3호
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• pp.130-135
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• 2008

The haplotypes of a 200 kb region in the human chromosome X terminal band (q28) were analyzed using the International HapMap Project Phasell data, which had been collected for three analysis panels (YRI, CEU, and CHB＋JPT). When multiple linkage disequilibrium blocks were encountered for a panel, the neighboring haplotypes that had crossover rate of 5% or more in the panel were combined to generate 'haploid' configurations. This resulted in 8, 7, and 5 'haploid' configurations for the panels of YRI, CEU, and CHB＋JPT, respectively. The multiple sequence alignment of these 'haploids' was used for the calculation of allele-sharing distances and the subsequent principal coordinate analysis. Two 'haploids' in CEU and CHB＋JPT were hypothesized as 'parental' in light of the observations that the successive recombinants of these haploids can model two other haploids in CEU and CHB＋JPT, and that their configurations were consistent with those in YRI. This study demonstrates the utility of haplotype phylogeny in understanding population evolution.

• 한국자동차공학회논문집
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• 제1권1호
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• pp.1-13
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• 1993

The three-dimensional numerical analysis for in-cylinder flow of four-valve engine without intake port has been successfully computed. These computations have been performed using technique of the general coordinate transformation based on the finite-volume method and body-fitted non-orthogenal grids using staggered control volume and covariant variable as dependent one. Computations are started at intake valve opening and are carried through top-dead-center of compression. A k-$\varepsilon$model is used to represent turbulent transport of momentum. The principal study is the evolution of interaction between mean flow and turbulence and of the role of swirl and tumble in generating near TDC turbulence. Results for three different inlet flow configuration are presented. From these results, complex flow pattern may be effective for promoting combustion in spark-ignition engines and kinetic energy of mean flow near TDC is well converted into turbulent kinetic energy.