• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1187-1193
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• 2014

This paper presents an effective motion estimation to improve the performance of the motion compensated temporal filtering (MCTF) which is a core part of the wavelet-based scalable video coding. The proposed scheme makes the motion vector field uniform by the modified median operation and the search strategies using adjacent motion vectors, in order to enhance the pixel connectivity which is significantly relevant to the performance of the MCTF. Moreover, the motion estimation with variable block sizes that reflects the features of frames is introduced for further correlation improvement of the motion vector field. Experimental results illustrate that the proposed method reduces the decomposed energy on the temporal high frequency subband frame up to 30.33% in terms of variance compared to the case of the full search with fixed block sizes.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1985-1990
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• 2008

1970년대 이후의 고도경제성장기에 치수대책과 동시에 건설골재로서 하상이 굴착된 하천이 많으며, 국가하천 지정구간외에서는 평균하상고가 1.0m 이상 저하한 하천구간도 많다. 또한 국가하천은 상류의 사방공사나 댐건설에 의한 영향이 복합적으로 하도에 나타나고 있어 하상굴착이 하도특성에 어떤 영향을 미치는가를 실증적(實證的)으로 검증하는 것은 어려운 과제이다. 하천에서의 골재채취는 제방부의 침식에 의한 호안파괴, 하상저하에 따른 교량이나 취수보 등 구조물의 기초 노출이 치수적인 문제를 야기할 뿐만 아니라, 단시간내에 하도의 지형구조를 급격하게 변화시켜 여울 소의 하상구조 교란이나 수중 및 하천변의 서식처 파괴 등으로 하천의 물리적 환경에 큰 영향을 미침으로써 생태계를 교란하거나 파괴하는 결과를 초래하게 된다. 본 연구에서는 골재채취로 인하여 교란된 하천의 복원 및 적응관리 계획수립의 전단계에 필요한 교란평가기법을 개발하기 위하여 황강, 남강 및 감천을 대상으로 하여 대조구간과 교란구간을 선정하고 조사 분석하였다. 하천골재 채취가 없거나 경미한 대조구간에서는 홍수량이 변하지 않으면 terrace 모양의 하안부 재료가 하상재료와 거의 같기 때문에 홍수가 있으면 침식된 원래의 하폭으로 회복되는 방향으로 변하지는 않는 경향이 나타났다. 반면에 골재채취가 많은 경우 큰 홍수시의 저수로부의 수심을 증가시키기 때문에 수충부 등의 최심하상고가 크게 되는 경향이 있었으며, 고수부는 침수되는 빈도와 수심이 감소하기 때문에 토사의 퇴적속도(고수부의 상승속도)의 감소, 퇴적물의 세립화 경향이 나타나서 모래, 실트가 퇴적하지 않는 고수부상에 모래, 실트가 퇴적되는 경우가 있고, 반대로 고수부의 퇴적속도가 상승하는 경우도 있었다. 골재채취로 횡단방향의 평탄화가 초래되어 여울 소의 하상구조가 교란됨과 동시에 구간별로 종단경사가 완만해지며, 대부분 교량부에 하상유지공을 설치해야 할 정도로 하상경사가 급변하는 구간이 다수 조사되었다. 또한 선행연구에서 개발된 하상서식환경, 하상재료, 유속/수심상황, 유사퇴적, 하도흐름상태, 하도개수, 여울출현 빈도, 하안 안정성, 식생피복 및 하반림 등 10개의 교란평가항목을 적용하여 대조구간과 비교 평가하였다.

• Journal of the Korea Society of Computer and Information
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• v.17 no.11
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• pp.11-18
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• 2012

Debris flow deposition model is a model to predict affected areas by debris flow and random walk model (RWM) was used to build the model. Although the model was proved to be effective in the prediction of affected areas, the model has several free parameters decided experimentally. There are several well-known methods to estimate parameters, however, they cannot be applied directly to the debris flow problem due to the small size of training data. In this paper, a modified neural network, called pseudo sample neural network (PSNN), was proposed to overcome the sample size problem. In the training phase, PSNN uses pseudo samples, which are generated using the existing samples. The pseudo samples smooth the solution space and reduce the probability of falling into a local optimum. As a result, PSNN can estimate parameter more robustly than traditional neural networks do. All of these can be proved through the experiments using artificial and real data sets.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.2
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• pp.166-172
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• 2018

To develop and evaluate the real-time SAR(Synthetic Aperture Radar) motion measurement system, true antenna phase center(APC) positions during SAT(Synthetic Aperture Time) are needed. In this paper, CDGPS(Carrier phase Differential Global Positioning System) post processing method is proposed to get the true APC position for spotlight SAR image formation. The CDGPS position is smoothed to remove high frequency noise which exists inherently in the carrier phase measurement. This paper shows smoothed CDGPS data is enough to provide the true APC for high-quality SAR image formation through motion measurement result, phase error estimation and IRF(Impulse Response Function) analysis.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.146-154
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• 2014

The local binary pattern (LBP) scheme that is one of the texture classification methods normally uses the distribution of flat, edge and corner patterns. However, it cannot examine the edge direction and the pixel difference because it is a sort of binary pattern caused by thresholding. Furthermore, since it cannot consider the pixel distribution, it shows lower performance as the image size becomes larger. In order to solve this problem, we propose a sub-classification method using the edge direction distribution and eigen-matrix. The proposed sub-classification is applied to the particular texture patches which cannot be classified by LBP. First, we quantize the edge direction and compute its distribution. Second, we calculate the distribution of the largest value among eigenvalues derived from structure matrix. Simulation results show that the proposed method provides a higher classification performance of about 8 % than the existing method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11C
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• pp.662-672
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• 2011

This paper presents a new edge-preserving algorithm and its VLSI architecture for block artifact reduction. Unlike previous approaches using block classification, our algorithm utilizes pixel classification to categorize each pixel into one of two classes, namely smooth region and edge region, which are described by the edge-preserving maps. Based on these maps, a two-step adaptive filter which includes offset filtering and edge-preserving filtering is used to remove block artifacts. A pipelined VLSI architecture of the proposed deblocking algorithm for HD video processing is also presented in this paper. A memory-reduced architecture for a block buffer is used to optimize memory usage. The architecture of the proposed deblocking filter is prototyped on FPGA Cyclone II, and then we estimated performance when the filter is synthesized on ANAM 0.25 ${\mu}m$ CMOS cell library using Synopsys Design Compiler. Our experimental results show that our proposed algorithm effectively reduces block artifacts while preserving the details.

• The Journal of the Acoustical Society of Korea
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• v.28 no.6
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• pp.491-498
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• 2009

This paper presents the design method of an impedance matching network using an isolation transformer and the Chebyshev filter function for the high efficiency and the flat power driving of an underwater acoustic piezoelectric transducer. The proposed impedance matching network is designed for minimizing the reactance component of transducer and having the flat power response in the wide frequency range. We design a low pass filter with ladder-type circuit using the Chebyshev function as standard prototype filter function. In addition, we design the impedance matching network which is suitable for the equivalent circuit of transducer and the turn ratio of transformer through the bandpass frequency transformation. The proposed method is applied to the simulated dummy load of the tonpilz-type transducer operating in the middle frequency range. The simulation results are compared with the measured characteristics and the validity of the proposed method is verified.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1149-1158
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• 2003

Content adaptive watermark embedding algorithm using a stochastic image model in the multiwavelet transform is proposed in this paper. A watermark is embedded into the perceptually significant coefficients (PSCs) of each subband using multiwavelet transform. The PSCs in high frequency subband are selected by SSQ, that is, by setting the thresholds as the one half of the largest coefficient in each subband. The perceptual model is applied with a stochastic approach based on noise visibility function (NVF) that has local image properties for watermark embedding. This model uses stationary Generalized Gaussian model characteristic because watermark has noise properties. The watermark estimation use shape parameter and variance of subband region. it is derive content adaptive criteria according to edge and texture, and flat region. The experiment results of the proposed watermark embedding method based on multiwavelet transform techniques were found to be excellent invisibility and robustness.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.3
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• pp.48-58
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• 2009

Geo-graphical routing protocols as GPSR are known to be very suitable and useful for vehicular ad-hoc networks. However, a corresponding node can include some stale neighbor nodes being out of a transmission range, and the stale nodes are pone to get a high priority to be a next relay node in the greedy mode. In addition, some useful redundant information can be eliminated during planarization in the recovery mode. This paper deals with a new recovery mode, the Greedy Border Superiority Routing(GBSR), along with an Adaptive Neighbor list Management(ANM) scheme. Each node can easily treat stale nodes on its neighbor list by means of comparing previous and current Position of a neighbor. When a node meets the local maximum, it makes use of a border superior graph to recover from it. This approach improve the packet delivery ratio while it decreases the time to recover from the local maximum. We evaluate the performance of the proposed methods using a network simulator. The results shown that the proposed protocol reveals much better performance than GPSR protocol. Please Put the of paper here.

• Korean Journal of Environment and Ecology
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• v.27 no.5
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• pp.614-624
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• 2013

The purpose of this study is to offer the raw data for establishing the plan of disaster prevention and the continuous conservation of soil ecosystem by grasping the potential soil loss and the danger of erosion using RUSLE method on whole districts in Gyeongju National Park, Korea. In the results of the average amount of soil erosion for the year, the average of all districts was 5.7 ton/ha in annual, and Namsan district was the highest in 7.6 ton/ha in annual and Seoak district was the lowest in 2.1 ton/ha in annual. The dangerous district due to the soil erosion was analyzed as under 1%, and Gumisan and Hwarange district was not serious. But Namsan district was higher than others, especially, there was intensive in all over Geumohbong. Therefore, to protect the all over Geumohbong, we will establish the valid of restoration and management. The types of land cover in Gyeongju National Park mostly showed forest, and as the average amount of soil erosion in forest was 3.7 ton/ha in annual, there was good condition. In the results of the amount of soil erosion due to landform, the deep canyon showed as 7.3 ton/ha in annual per unit area, secondly, the U-shaped valley was analyzed as 6.1 ton/ha in annual. The plain and high ridge were predicted that there occurred the small amount of soil erosion. In future, if we will analyze the amount of soil erosion in Korean National Parks, we will offer the help to establishing the plan of conservation and restoration on soil ecosystem in whole National Parks.