• Title/Summary/Keyword: Discrete Approximation

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Developed using Quadcopter Crop Protection and Monitoring System from Wild Animals (쿼드콥터를 이용한 야생동물로부터 농작물보호 및 감시 시스템 개발)

  • Lim, Hyeon-Woo;Jie, Min-Seok;Choi, Won-Hyuck
    • Journal of Korea Entertainment Industry Association
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    • v.10 no.4
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    • pp.303-310
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    • 2016
  • Due to population explosion and develop of the industry, expressways, national roads and railways has been developed a lot. But it increased the disconnection of the ecosystem. The phenomenon of wild animals' habitat simplification has been increased. The damage appeared in succession because of the harmful wild animal. Our country is making efforts relief of some affected farming household's financial compensation. But the affected populations can't sleep at night or they are suffering in their basic life because of this kind of night patrol. This research is based on the study of wild animal's ecosystem and their habits, generate and regenerate supersonic waves and infrasound, prevent wild animal's approach to some extent and stop the approximation effectively, focusing on develop a quadcopter about discrete pulses system.

Estimation and Mapping of Soil Organic Matter using Visible-Near Infrared Spectroscopy (분광학을 이용한 토양 유기물 추정 및 분포도 작성)

  • Choe, Eun-Young;Hong, Suk-Young;Kim, Yi-Hyun;Zhang, Yong-Seon
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.6
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    • pp.968-974
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    • 2010
  • We assessed the feasibility of discrete wavelet transform (DWT) applied for the spectral processing to enhance the estimation performance quality of soil organic matters using visible-near infrared spectra and mapped their distribution via block Kriging model. Continuum-removal and $1^{st}$ derivative transform as well as Haar and Daubechies DWT were used to enhance spectral variation in terms of soil organic matter contents and those spectra were put into the PLSR (Partial Least Squares Regression) model. Estimation results using raw reflectance and transformed spectra showed similar quality with $R^2$ > 0.6 and RPD> 1.5. These values mean the approximation prediction on soil organic matter contents. The poor performance of estimation using DWT spectra might be caused by coarser approximation of DWT which not enough to express spectral variation based on soil organic matter contents. The distribution maps of soil organic matter were drawn via a spatial information model, Kriging. Organic contents of soil samples made Gaussian distribution centered at around 20 g $kg^{-1}$ and the values in the map were distributed with similar patterns. The estimated organic matter contents had similar distribution to the measured values even though some parts of estimated value map showed slightly higher. If the estimation quality is improved more, estimation model and mapping using spectroscopy may be applied in global soil mapping, soil classification, and remote sensing data analysis as a rapid and cost-effective method.

Detection of Gradual Transitions in MPEG Compressed Video using Hidden Markov Model (은닉 마르코프 모델을 이용한 MPEG 압축 비디오에서의 점진적 변환의 검출)

  • Choi, Sung-Min;Kim, Dai-Jin;Bang, Sung-Yang
    • Journal of KIISE:Software and Applications
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    • v.31 no.3
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    • pp.379-386
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    • 2004
  • Video segmentation is a fundamental task in video indexing and it includes two kinds of shot change detections such as the abrupt transition and the gradual transition. The abrupt shot boundaries are detected by computing the image-based distance between adjacent frames and comparing this distance with a pre-determined threshold value. However, the gradual shot boundaries are difficult to detect with this approach. To overcome this difficulty, we propose the method that detects gradual transition in the MPEG compressed video using the HMM (Hidden Markov Model). We take two different HMMs such as a discrete HMM and a continuous HMM with a Gaussian mixture model. As image features for HMM's observations, we use two distinct features such as the difference of histogram of DC images between two adjacent frames and the difference of each individual macroblock's deviations at the corresponding macroblock's between two adjacent frames, where deviation means an arithmetic difference of each macroblock's DC value from the mean of DC values in the given frame. Furthermore, we obtain the DC sequences of P and B frame by the first order approximation for a fast and effective computation. Experiment results show that we obtain the best detection and classification performance of gradual transitions when a continuous HMM with one Gaussian model is taken and two image features are used together.

Verification of the Radiation Shielding Analysis of Shipping Cask Using Deterministic and Probabilistic Methods (결정론적인 방법과 확률론적인 방법을 이용한 수송용기 방사선차폐해석의 비교 및 검증)

  • Yoon, Jeong-Hyoung;Lee, In-Koo;Bang, Kyoung-Sik;Choi, Byoung-Il;Kim, Chong-Kyoung
    • Journal of Radiation Protection and Research
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    • v.21 no.1
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    • pp.17-25
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    • 1996
  • In this study, to set-up the calculation method of radiation shielding of the KSC-4 shipping cask which is being used for spent fuel transportation, the pre-existing two calculation methods, deterministic and probabilistic methods were tested. For the first, the DOT4.2 computer code adopting the deterministic theory was applied for the calculation of effective neutron shielding under assumption of continuous wall thickness of the cask. To verify the first results, the probabilistic theory was used as an alternate calculation. In this case MCNP4A computer code adopting the probabilitic theory was used. And same approximation was obtained from the two different shielding calculations. From the results, it could be confirmed that the design and calculation method used for the radiation shielding of the KSC-4 was adequate and sufficiently safe to meet the design and QA requirements of 10CFR71 Appendix H.

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Fast Bayesian Inversion of Geophysical Data (지구물리 자료의 고속 베이지안 역산)

  • Oh, Seok-Hoon;Kwon, Byung-Doo;Nam, Jae-Cheol;Kee, Duk-Kee
    • Journal of the Korean Geophysical Society
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    • v.3 no.3
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    • pp.161-174
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    • 2000
  • Bayesian inversion is a stable approach to infer the subsurface structure with the limited data from geophysical explorations. In geophysical inverse process, due to the finite and discrete characteristics of field data and modeling process, some uncertainties are inherent and therefore probabilistic approach to the geophysical inversion is required. Bayesian framework provides theoretical base for the confidency and uncertainty analysis for the inference. However, most of the Bayesian inversion require the integration process of high dimension, so massive calculations like a Monte Carlo integration is demanded to solve it. This method, though, seemed suitable to apply to the geophysical problems which have the characteristics of highly non-linearity, we are faced to meet the promptness and convenience in field process. In this study, by the Gaussian approximation for the observed data and a priori information, fast Bayesian inversion scheme is developed and applied to the model problem with electric well logging and dipole-dipole resistivity data. Each covariance matrices are induced by geostatistical method and optimization technique resulted in maximum a posteriori information. Especially a priori information is evaluated by the cross-validation technique. And the uncertainty analysis was performed to interpret the resistivity structure by simulation of a posteriori covariance matrix.

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On the Evaluation of Construction Standards Based on Seismic Velocities Obtained In-Situ and through Laboratory Rock Tests (현장 및 실내 측정 탄성파 속도에 근거한 암반평가 기준에 대한 고찰)

  • Lee, Kang Nyeong;Park, Yeon Jun
    • Tunnel and Underground Space
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    • v.27 no.4
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    • pp.230-242
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    • 2017
  • Seismic velocities measured from in-situ tests (n=177) and through rock core samples (n=1,035) are reviewed in light of construction standards, widely used standards as a first-hand approximation of rock classification solely based on seismic velocities. In-situ down hole tests and refraction survey for soft rocks showed seismic velocities of 1,400~2,900 m/s which is faster than those specified in construction standards. For moderate~ hard rocks, in-situ down hole tests and refraction survey showed 2,300~3,800 m/s which roughly corresponds with the range specified in the construction standards. A similar trend is also observed for seismic velocities measured from rock core samples. The observed differences between construction standards and seismic velocities can be explained in two ways. If construction standards are correct the observed differences may be explained with seismic velocities affected by underlying fast velocities and also possibly with selection of intact cores for velocity measurement. Alternatively, construction standards may have intrinsic problems, namely artificial discrete boundaries between soft rocks and moderate rocks, application of foreign standards without consideration of geologic setting and lack of independent verification steps. Therefore, we suggest a carefully designed verification studies from a test site. We also suggest that care must be exercised when applying construction standards for the interpretation and accessment of rock mass properties.

A Study of Rayleigh Damping Effect on Dynamic Crack Propagation Analysis using MLS Difference Method (MLS 차분법을 활용한 동적 균열전파해석의 Rayleigh 감쇠영향 분석)

  • Kim, Kyeong-Hwan;Lee, Sang-Ho;Yoon, Young-Cheol
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.6
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    • pp.583-590
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    • 2016
  • This paper presents a dynamic crack propagation algorithm with Rayleigh damping effect based on the MLS(Moving Least Squares) Difference Method. Dynamic equilibrium equation and constitutive equation are derived by considering Rayliegh damping and governing equations are discretized by the MLS derivative approximation; the proportional damping, which has not been properly treated in the conventional strong formulations, was implemented in both the equilibrium equation and constitutive equation. Dynamic equilibrium equation including time relevant terms is integrated by the Central Difference Method and the discrete equations are simplified by lagging the velocity one step behind. A geometrical feature of crack is modeled by imposing the traction-free condition onto the nodes placed at crack surfaces and the effect of movement and addition of the nodes at every time step due to crack growth is appropriately reflected on the construction of total system. The robustness of the proposed numerical algorithm was proved by simulating single and multiple crack growth problems and the effect of proportional damping on the dynamic crack propagation analysis was effectively demonstrated.