• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.3
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• pp.33-40
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• 2014

This study were conducted to evaluate the N mineralization and nitrification rates and to estimate the losses of total carbon and nitrogen by runoff water in soils cooperated with organic composts and bio-char during corn cultivation. For the experiment, the soil texture used in this study was clay loam, and application rates of chemical fertilizer and bio-char were $230-107-190kg\;ha^{-1}$($N-P_2O_5-K_2O$) as recommended amount after soil test and 0.2% to soil weight. The soil samples were periodically taken at every 15 day intervals during the experimental periods. The treatments were consisted of cow compost, pig compost, swine digestate from aerobic digestion system, and their bio-char cooperation. For N mineralization and nitrification rates, it was shown that there were generally low in the soil cooperated with bio-char as compared to the only application plots of different organic composts except for 47 days after sowing. Also, they were observed to be highest in the application plot of swine digestate from aerobic digestion system. For loss of total carbon by run-off water, it was ranged from 1.5 to $3.0kg\;ha^{-1}$ in the different organic compost treatment plots. However, Loss of total carbon with bio-char could be reduced at $0.4kg\;ha^{-1}$ in PC treatment plot. Also, with application of bio-char, total nitrogen was estimated to be reduced at 4.2 (15.1%) and $3.8(11.8%)kg\;ha^{-1}$ in application plots of pig compost and swine aerobic digestate, respectively.

• The Journal of the Acoustical Society of Korea
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• v.11 no.1E
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• pp.73-78
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• 1992

시벼형 신호인 음성 신호의 분석에 칼만필터를 이용하였다. 일반적인 음성 분석은 프레임단위의 처리방법인 선형 예측 부호화 기법을 주로 이용하지만 음성의 시변 특성을 파악하는데에는 적절하지 못 하다. 따라서 순차적인 추정기법으로 많이 이용되는 칼만 필터를 음성 분석에 적용하였다. 또한 음성과 같은 시변신호에서는 과거 신호의 잡음의 분산값에 적당한 가중치를 부가하므로써 과거의 신호에 의해 서 현재의 추정값에 미치는 영향을 줄였으며 이를 음성의 천이 구간에서의 파라메타 추정에 사용하였 다. 그리고 음성신호 모델에서 생기는 모델링 오차는 일반적으로 백색 가우시안 잡음으로 가정하고 있 으나 이는 자음과 같은 무성음에서 특징 파라메타 푸정에는 오차가 적지만 모음등의 유성음에서는 음성 발생시의 여기신호인 펄스열에 의해서 많은 모델링 오차를 생기게 한다. 따라서 모델링 오차신호는 Non-Gaussian 확률분포로 가정한 후 로버스트 칼만 필터를 사용하여 합성으멩 대해 특징 파라메터를 추출하였다.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.709-712
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• 1998

본 논문에서는 지능형 교통 정보처리 시스템의 구축을 위해 기존의 불완전한 영상분할 기법을 후처리 과정에서 자동차의 특징과 context 정보로 구성된 지식기반에 의한 전문가 시스템으로 보완함으로써 자연적인 영상에서도 정확한 영상분할이 가능한 컴퓨터 시각장치 알고리듬을 제안하였다. 다양한 환경에서 구축한 3000여개의 영상 데이터베이스 중 100여개의 영상에 대해 위의 차량검출 기법을 적용한 결과, 영상의 대비도가 높을 경우 대부분의 영상에서 약 10%의 오차 범위 내에서 정확한 영역검출이 가능하였으며, 교통량의 최적제어를 위한 지능적 신호체계 구축의 자동화에 사용될 수 있다.

• Computational Structural Engineering
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• v.11 no.1
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• pp.261-274
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• 1998

In this paper, local and global error estimates for the element-free Galerkin (EFG) method are proposed. The essence of proposed error estimates is to use the difference between the values of the projected stress and these given directly by the EFG solution. The stress projection can be obtained simply by taking product of shape function based on a different domain of influence with the stresses at nodes. In this study, it was found that the effectivity index is optimized if the domain of influence in stress projection procedure is the smallest that retains regularity of the matrices in EFG. Numerical tests are shown for various 1D and 2D examples illustrating the good effectiveness of the proposed error estimator in the global energy norm and in the local error estimates.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.203-205
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• 2019

위성항법시스템의 안정적인 정보 제공의 요구사항은 점차 증가하고 있지만, 의도적인 전파교란 및 자연환경에 의하여 성능이 저하된다. eLoran 시스템은 위성항법시스템의 단점을 보완하기위한 대표적인 지상파항법시스템으로 고출력 신호로 의도적인 전파교란에 강인한 장점이 있다. eLoran 시스템에서 사용자는 E-field 또는 H-field 2가지 종류의 수신 안테나를 사용 환경에 따라 적합한 것을 사용한다. 접지가 필요없고 상대적으로 주변 전자장비의 잡음에 강인한 H-field안테나는 두 개의 루프로 구성되어 루프간의 위상과 이득차이로 일정한 원형의 지향성을 가지지 못한다. 그러므로 수신한 신호의 방향에 따라 측정치의 변화가 발생하므로 H-field 안테나를 사용시에는 수신하는 신호의 방향에 따른 오차를 제거해야한다. 본 논문에서는 H-field 안테나와 송신국간의 기하학적 방향오차에 따른 오차를 제거하기 위한 후처리 필터를 제안하였다. eLoran 모의 신호생성기를 활용하여 오차를 분석하고 모델링하여 제거하는 기법을 개발하였다. 제안한 기법을 검증하기 위하여 시뮬레이션과 차량실험을 통하여 오차를 확인하고 제거하여 성능향상을 확인하였다.

• Korean Journal of Plant Resources
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• v.28 no.2
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• pp.271-278
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• 2015

This experiment was carried out to evaluate the effects of green manure crops on the changes of chemical properties and microorganisms in soil of continuous ginger cultivation. The biomass and nitrogen absorption of green manure crop were the highest in crimson clover. After cropping, soil phosphate content was the lowest in orchard grass, however, T-N content was the highest of hairy vetch > crimson clover > orchard grass. Also real-time PCR analysis was conducted to measure density of Pythium zingiberum in soil of before and after incorporation of green manure crop. Density of P. zingiberum was the lowest of all the green manures. In this results are summarized that green manure cropping reduced salt accumulation and density of P. zingiberum in continuous ginger cultivation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.185-198
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• 2016

In this work, experimental errors from an impact hammer test were investigated to develop a statistic-based technique for updating a finite element model. Digital signal processing was analyzed by using theoretical models and experiments when errors occurred during the experimental procedure. First, the duration time and peak level of the excitation signal, the stiffness and position of elastic springs connecting the specimen as well as the support, position and mass of the accelerometer were considered as error factors during the experiment. Then the picket fence effect, leakage, and exponential window function were considered as candidate error factors during the digital signal processing. Finally, methods to reduce errors are suggested.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.557-564
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• 2001

In general, several moving regions with different motions coexist in a block located on motion boundaries in the block-based motion estimation. In this case the motion compensation error(MCEs) are different with the moving regions. This is inclined to deteriorate the quality of motion compensated images because of the inaccurate motions estimated from the conventional mean absolute error(MAE) based matching function in which the matching error per pixel is accumulate throughout the block. In this paper, we divided a block into the regions according to their motions using the motion information of the spatio-temporally neighboring blocks and calculate the average MCF for each moving mentioned. From the simulation results, we showed the improved performance of the proposed method by comparing the results from other methods such as the full search method and the edge oriented block matching algorithm. Especially, we improved the quality of the motion compensated images of blocks on motion boundaries.

• The KIPS Transactions:PartB
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• v.17B no.4
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• pp.275-286
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• 2010

Reversible watermarking which can preserve the original quality of the digital contents and protect the copyright has been studied actively. Especially, in medical, military, and art fields, the need for reversible watermarking is increasing. This paper proposes a high-capacity reversible watermarking through predicted error expansion and error estimation compensation. Watermark is embedded by expanding the difference histogram between the original value and the predicted value. Differently from previous methods calculating the difference between adjacent pixels, the presented method calculates the difference between the original value and the predicted value, and that increases the number of the histogram value, where the watermark is embedded. As a result, the high capacity is achieved. The inserted watermark is extracted by restoring the histogram between the original value and the predicted value. To prove the performance, the presented algorithm is compared with other previous methods on various test images. The result supports that the presented algorithm has a perfect reversibility, a high image quality, and a high capacity.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.1
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• pp.9-13
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• 2002

A pool image processing measurement method has been developed to improve the examination efficiency and to minimize the errors of dimensional measurements of spent fuel assemblies in pool. Diameter and length measurements of mock-up fuel rods using the image processing system are $-0.24{\pm}0.03mm,\;0.34{\pm}0.06mm$ on the basis of the true value and their maximum errors are within -0.3 and 0.4mm, respectively, According to the result of dimensional measurement of spent fuels in pool, the upper and lower part diameter and mid part diameter of fuel rods of the J44 fuel assembly irradiated for 2 cycles in the Kori-2 nuclear reactor were decreased by about 2.0 and 3.0% in comparison with design values, respectively. The length of fuel rods was elongated by about 0.4%. The change behavior of diameter and length. of fuel rods of the F02 fuel assembly irradiated for 3 cycles in the Kori-1 nuclear reactor showed a trend similar to the results of J44.