• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.403-408
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• 2005

The techniques of estimating angle of arrival(AOA) have played a key role for enhancement of wireless communications using array antennas. Among those techniques, the superresolution algorithms, such as MUSIC and ESPRIT, calculate the covariance matrix of the array output vectors which are observed at the array antennas, and then by using eigen-decomposition of the covariance matrix, they estimate AOAs of the received signals with high accuracy. However, superresolution algorithms based eigenvalue decomposition fails to estimate AOAs under multipath environments. Under multipath environments, it is difficult to estimate AOAs of the received signals due to coherency and high-correlation. To resolve coherent signals, the covariance matrix is calculated by using the conventional spatial smoothing technique, and then the techniques based on eigen-descomposition is applied. The result of the conventional spatial smoothing technique, however, is obtained at the cost of losing effective spatial aperture. Moreover, the conventional technique ignores any information in the cross-correlations of the array outputs the subarrays. As the result, the performance for AOA estimation is degraded. In this paper, we propose a new spatial smoothing technique, which consider the cross-correlation for subarrays. By computer simulation, the AOA estimation performance of the proposed method is compared with the conventional method and evaluated.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.243-244
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• 2013

본 연구의 목적은 온라인 스포츠용품 이용고객들을 대상으로 사회적 실재감, 웹사이트 명성, 상호작용성과 고객신뢰, 관계몰입 및 고객충성도와의 구조적관계를 규명하는 것이다. 이러한 연구목적을 달성하기 위하여 P, U광역시 및 K도에 소재한 5개 대학에서 편의표본추출법을 이용하여 최종 458명을 유효 표본으로 선정하였으며 본 연구의 자료로 이용하였다. 본 연구에서는 SPSS WIN 14.0 통계 패키지와 AMOS 7.0프로그램을 활용하여 빈도분석, 탐색적 요인분석, 신뢰도분석, 상관관계분석, 확인적 요인분석, 구조방정식 모형분석을 실시하였다. 본 연구에서 얻은 결론은 다음과 같다. 첫째, 온라인 스포츠용품 이용고객의 사회적 실재감, 웹사이트 명성, 상호작용성은 고객신뢰에 유의한 영향을 미친 것으로 나타났다. 둘째, 온라인 스포츠용품 이용고객의 사회적 실재감, 웹사이트 명성, 상호작용성은 유의한 영향을 미친 것으로 나타났다. 셋째, 고객신뢰는 고객충성도(재구매의도, 구전의도)에 유의한 영향을 미친 것으로 나타났다. 넷째, 관계몰입은 고객충성도(재구매의도, 구전의도)에 유의한 영향을 미친 것으로 나타났다.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.116-122
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• 2006

This study was carried out to compare physical properties of the horticultural substrates measured by the European standard methods (CEN methods) and the Rural Development Administration of Korea methods (RDA methods). Sixty horticultural substrates including 40 marketed substrates and 10 organic and inorganic raw materials such as peat moss, coir dust, rice hull, perlite and zeolite were sampled. The samples were then analyzed for 6 physical properties by both CEN methods and RDA methods. The results of both methods were analyzed by linear regression. Bulk density ($R^2=0.8304$), particle density ($R^2=0.8136$) and porosity ($R^2=0.6374$) values measured by the two methods were highly significant. Whereas those for easily available water (EAW, $R^2=0.3327$), water volume ($R^2=0.2692$) and air volume ($R^2=0.0739$) were not significant. Further research is needed to facilitate the conversion between the two methods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.137-145
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• 1990

Six commercial rice varieties were cultivated at different locations in 1987 and 1988. Rice samples harvested from 8 to 20 locations for a variety each year were used to measure or observe grain appearance, amylose content and alkali digestibility, cooked rice texture using rheometer, gelatinization and viscosity of rice flour using amylograph, and eating Quality of cooked rice by sensory evaluation. Relationship between Quality characteristics showing large locational variation were analized to approach the long-term objective, rice grain Quality standardization. Percent white-center and white-belly grain of the same variety showed great variation between locations, but did not affect on 1000-grain weight, amylose content and alkali digestibility, amylogram and rheogram characteristics, and eating Quality of cooked rice. Positive correlationship were obtained between maximum viscosity and break down, and maximum viscosity and alkali digestibility. Set back was correlated negatively with maximum viscosity, break down and alkali digestibility. Rice samples having significantly lower values of maximum viscosity and break down and higher set back value at the same time showed higher ADV and lower texture palatability index (TPI) and viscousness/hardness ratio (Vi/H), and lower sensory evaluation score of cooked rice compared with those of rices having typically higher values of maximum viscosity and break down and lower set back value. When TPI, Vi/H and overall sensory eating score of cooked rices measured were divided into three categories, high, medium and low using deviation from locational mean value of a variety, many of rice samples having high TPI or high Vi/H showed medium or high in overall sensory eating score of cooked rice.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.934-937
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• 1992

The partial discharge signal can be used as the detection signal of the deterioration of the power transformer insulation. Detecting this signal, the insulation failure and the point, in which the partial discharge is generated, could be predicted. In this paper, we study to predict the point, and find that the cross correlation method could predict the point accurately. Also, experimental system and the results are presented here.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.99-102
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• 1990

Cross correlation method was newly applied for the calculation of latency of evoked otoacoustic emission. The latency was calculated from the main peak of cross correlation function, which is one of possible definition of latency. The output was also compared with those of conventional autocorrelation method. The results show that cross correlation method has better performance than that of conventional method.

• Journal of IKEEE
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• v.6 no.1 s.10
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• pp.102-110
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• 2002

An effective scheme to detect and diagnose multiple failures in a dynamic system is described for the case where the measurement noise is correlated sequentially in time. It is based on the modified interacting multiple model (MIMM) estimation algorithm in which a generalized decorrelation process is developed by employing the autoregressive (AR) model for the colored noise and applying measurement difference method.

• Magazine of the Korea Concrete Institute
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• v.9 no.6
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• pp.195-206
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• 1997

산업폐기물인 폐주물사를 재활용하여 에너지절감과 환경오염방지효과를 얻을 수 있다. 반요인실험법을 사용하여 폐주물사를 잔골재에 일정비율 치환한 콘크리트의 적정배합설계제시를 위한 예비실험에서 물-시멘트비, 폐주물사의 잔골재치환율, 잔골재율, 슬럼프와 같은 주요변수와 변수사이의 2차상호작용을 파악하였다. 예비실험결과 폐주물사의 잔골재치환율 70%까지 실시하였을 때 폐주물사를 혼입한 콘크리트의 강도 발현에 가장 중요한 변수는 물-시멘트비로 분석되었고 폐주물사의 잔골재치환율은 거의 영향이 없는 것으로 분석되어 폐주물사를 콘크리트의 잔골재로 대체할 수 있음을 알 수 있었다. 각 변수의 2차상호작용에서는 폐주물사의 잔골재치환율과 잔골재율의 상관관계가 콘크리트의 강도발현에 가장 큰 영향을 미치는 것으로 나타났다. 목표압축강도에 대한 적정배합조건을 폐주물사의 잔골재 치환율에 따라 물-시멘트비, 잔골재율에 대해 제시하였다.

• Economic and Environmental Geology
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• v.28 no.3
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• pp.271-277
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• 1995

The geological information analysis based on spatial statistical techniques have been studied in relation to mineral exploration. The applicability of outlier detection using moving-window statistics and directional cross-variography analysis have been verified by using geochemical data sets surveyed in the Taebaek area for mineral exploration. The directional variogram analysis has been basically known as a geostatistical method for spatial continuity measures. In this study, the application of this proposed method was extended to measure spatial correlation or similarity problems between two geochemical elements. For the appraisal of the usefulness of this scheme, five kinds of variogram functions were computed for original data and revised data, obtained by removing outliers detected by moving-window statistics and the results were compared. It is concluded that these advanced spatial statistical methods at the interpretation stage of spatial similarity provide us with valuable quantitative results as decision-supporting information for regional mineral exploration task.

• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.285-291
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• 2017

Many methods have been studied to estimate the time delay between incoming signals to two receivers. In the case of the method based on the channel estimation technique, the relative delay between the input signals of the two receivers is estimated as an impulse response of the channel between the two signals. In this case, the characteristic of the channel has sparsity. Most of the existing methods do not take advantage of the channel sparseness. In this paper, we propose a time delay estimation method using BPD (Basis Pursuit Denoising) optimization technique, which is one of the sparse signal optimization methods, in order to utilize the channel sparseness. Compared with the existing GCC (Generalized Cross Correlation) method, adaptive eigen decomposition method and RZA-LMS (Reweighted Zero-Attracting Least Mean Square), the proposed method shows that it can mitigate the threshold phenomenon even under a white Gaussian source, a colored signal source and oceanic mammal sound source.