• Title/Summary/Keyword: Re-Estimation

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Efficient Technique of Motion Vector Re-estimation in Transcoding (트랜스 코딩에서의 효율적인 움직임 벡터 재추정 기법 연구)

  • 한두진;박강서;유희준;김봉곤;박상희
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.8
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    • pp.602-605
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    • 2004
  • A novel motion vector re-estimation technique for transcoding into lower spatial resolution is proposed. This technique is based on the fact that the block matching error is proportional to the complexity of the reference block with Taylor series expansion. It is shown that the motion vectors re-estimated by the proposed method are closer to optimal ones and offer better quality than those of previous techniques.

Reduction of Steady-State Error Using Estimation for Re-Entry Trajectory (추정을 이용한 재진입 궤적의 정상상태 오차감소)

  • 박수홍;이대우
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2001.11a
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    • pp.130-134
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    • 2001
  • In the re-entry control system, errors apt to induce because the time derivative of drag acceleration is analytically estimated. Still more, the difficulty of estimation of the exact drag coefficient in hypersonic velocity and the nun-reality of the scale height cause a steady-state drag error. This paper proposes the additional method of the disturbance observer. This reduces the steady-state drag error according to the following series. First, this method estimates a error in drag acceleration time derivative by the analytic calculation and then creates the new drag acceleration time derivative using the estimated error. The performance of the re-entry control system is verified about 32 reference trajectories.

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Comparison of Ballistic-Coefficient-Based Estimation Algorithms for Precise Tracking of a Re-Entry Vehicle and its Impact Point Prediction

  • Moon, Kyung Rok;Kim, Tae Han;Song, Taek Lyul
    • Journal of Astronomy and Space Sciences
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    • v.29 no.4
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    • pp.363-374
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    • 2012
  • This paper studies the problem of tracking a re-entry vehicle (RV) in order to predict its impact point on the ground. Re-entry target dynamics combined with super-high speed has a complex non-linearity due to ballistic coefficient variations. However, it is difficult to construct a database for the ballistic coefficient of a unknown vehicle for a wide range of variations, thus the reliability of target tracking performance cannot be guaranteed if accurate ballistic coefficient estimation is not achieved. Various techniques for ballistic coefficient estimation have been previously proposed, but limitations exist for the estimation of non-linear parts accurately without obtaining prior information. In this paper we propose the ballistic coefficient ${\beta}$ model-based interacting multiple model-extended Kalman filter (${\beta}$-IMM-EKF) for precise tracking of an RV. To evaluate the performance, other ballistic coefficient model based filters, which are gamma augmented filter, gamma bootstrapped filter were compared and assessed with the proposed ${\beta}$-IMM-EKF for precise tracking of an RV.

A Real-Time Virtual Re-Convergence Hardware Platform

  • Kim, Jae-Gon;Kim, Jong-Hak;Ham, Hun-Ho;Kim, Jueng-Hun;Park, Chan-Oh;Park, Soon-Suk;Cho, Jun-Dong
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.12 no.2
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    • pp.127-138
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    • 2012
  • In this paper, we propose a real-time virtual re-convergence hardware platform especially to reduce the visual fatigue caused by stereoscopy. Our unique idea to reduce visual fatigue is to utilize the virtual re-convergence based on the optimized disparity-map that contains more depth information in the negative disparity area than in the positive area. Our virtual re-convergence hardware platform, which consists of image rectification, disparity estimation, depth post-processing, and virtual view control, is realized in real time with 60 fps on a single Xilinx Virtex-5 FPGA chip.

Fuzzy Regression Model Using Trapezoidal Fuzzy Numbers for Re-auction Data

  • Kim, Il Kyu;Lee, Woo-Joo;Yoon, Jin Hee;Choi, Seung Hoe
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.16 no.1
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    • pp.72-80
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    • 2016
  • Re-auction happens when a bid winner defaults on the payment without making second in-line purchase declaration even after determining sales permission. This is a process of selling under the court's authority. Re-auctioning contract price of real estate is largely influenced by the real estate business, real estate value, and the number of bidders. This paper is designed to establish a statistical model that deals with the number of bidders participating especially in apartment re-auctioning. For these, diverse factors are taken into consideration, including ratio of minimum sales value from the point of selling to re-auctioning, number of bidders at the time of selling, investment value of the real estate, and so forth. As an attempt to consider ambiguous and vague factors, this paper presents a comparatively vague concept of real estate and bidders as trapezoid fuzzy number. Two different methods based on the least squares estimation are applied to fuzzy regression model in this paper. The first method is the estimating method applying substitution after obtaining the estimators of regression coefficients, and the other method is to estimate directly from the estimating procedure without substitution. These methods are provided in application for re-auction data, and appropriate performance measure is also provided to compare the accuracies.

Applicability Test of UK Design Flood Estimation Model FEH-ReFH to Korean Namcheon Watershed (영국의 설계홍수량 산정모형인 FEH-ReFH의 국내 남천유역 적용성 평가)

  • Kim, Sang-Ho;Ahn, So-Ra;Jang, Cheol-Hee;Kim, Seong-Joon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.16 no.3
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    • pp.68-80
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    • 2013
  • The purpose of this study is to evaluate the applicability of UK design flood estimation model, FEH-ReFH through rainfall-runoff simulation of Korean watershed. For the Nam stream watershed($165.12km^2$), the model was calibrated using 6 storm events. The watershed and hydrological characteristics for the model requirements was prepared by developing input data pre-processors based on open GIS. The parameters of rainfall loss rate and unit hydrograph were calibrated from the observed data. The results can be used for improving and standardizing the Korean design flood estimation method.

Engineering J-Integral Estimation for Internal Axial Surface Cracks in Cylinders (II) -Optimised Reference Stress Based Estimation- (실린더에 존재하는 축방향 표면균열에 대한 공학적 J-적분식 (II) - 최적참조응력에 기초한 방법-)

  • Kim, Jin-Su;Kim, Yun-Jae;Kim, Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.11
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    • pp.2442-2449
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    • 2002
  • This paper provides an reference stress based J estimation equation fur cylinders with finite internal axial surface cracks under internal pressure. In part 1, the J estimation equation based on deformation plasticity using Ramberg-Osgood (R-0) materials is proposed. In this paper, the developed CE/EPRI -type solutions ale then re-formulated based on the reference stress concept. Such a re-formulation provides a simpler equation for J. estimation are then further extended to combined internal pressure and bending. The proposed reference stress based J estimation equation is compared with elastic-plastic 3-D FE results using actual stress-strain data for a Type 304 stainless steel. Good agreement between the FE results and the proposed reference stress based J estimations provides confidence in the use of the proposed method to elastic -plastic fracture mechanics of pressurised piping.

Developing an Automatic System for Making a Placing Drawing and Quantity taking-off Cut and Bent Re Bar with Work Zone Information (설치 위치 정보를 포함한 배근시공상세도 작성 및 가공철근 자동 물량산출 시스템 개발)

  • Park, Hyeon-Yong;Lee, Seung-Hyun;Kang, Tai-Kyoung;Lee, Yoo-Sub
    • Journal of the Korea Institute of Building Construction
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    • v.8 no.2
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    • pp.63-70
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    • 2008
  • Reinforcing steel work plays an important role in terms of its structural performance or weight of construction cost for reinforced concrete structures. Precise estimation of re-bar quantity gives a basis for managing the reinforcing steel work effectively. However, the estimation process is still performed ineffectively based upon the expert's experience or manpower in spite of the advanced technology or improvement efforts. Therefore, the purpose of this research is to develop a prototype system for taking-off the quantity of reinforcing steel bars quickly and accurately in an order consistent with the specific members identified on the drawings. An estimate algorithm considering the connection, settlement and coating thickness of re-bars was suggested regarding to their replacement conditions which places more emphasis on constructibility. Also, this system produces the shop drawings automatically with the calculation results with work zone information.

A Motion Vector Re-Estimation Algorithm for Image Downscaling in Discrete Cosine Transform Domain (이산여현변환 공간에서의 영상 축소를 위한 움직임 벡터 재추정)

  • Kim, Woong-Hee;Oh, Seung-Kyun;Park, Hyun-Wook
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.39 no.5
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    • pp.494-503
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    • 2002
  • A motion vector re-estimation algorithm for image downscaling in discrete consine transform domain is presented. Kernel functions are difined using SAD (Aum of Absolute Difference) and edge information of a macroblock. The proposed method uses these kernel functions to re-estimate a new motion vector of the downscaled image. The motion vectors from the incoming bitstream of transcoder are reused to reduce computation burden of the block-matching motion estimation, and we also reuse the given motion vectors. Several experiments in this paper show that the computation efficiency and the PSNR (Peak Signal to Noise Ratio) and better than the previous methods.

An Efficient Video Watermarking Using Re-Estimation and Minimum Modification Technique of Motion Vectors (재예측과 움직임벡터의 변경 최소화 기법을 이용한 효율적인 비디오 워터마킹)

  • Kang Kyung-won;Moon Kwang-seok;Kim Jong-nam
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.6C
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    • pp.497-504
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    • 2005
  • We propose an efficient video watermarking scheme using re-estimation and minimum modification technique of motion vectors. Conventional methods based on motion vectors do watermarking using modification of motion vectors. However, change of motion vectors results in the degradation of video quality. Thus, our scheme minimizes the modification of the original motion vectors and replaces an original motion vector by the adjacent optimal motion vector using re-estimation of motion vectors to avoid degradation of video quality. Besides, our scheme guarantees the amount of embedded watermark data using the adaptive threshold considering for an efficient video watermarking. In addition, this is compatible with current video compression standards without changing the bitstream. Experimental result shows that the proposed scheme obtains better video quality than other previous algorithms by about $0.6{\sim}1.3\;dB$.