• Title/Summary/Keyword: computational estimation

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Hybrid SNR-Adaptive Multiuser Detectors for SDMA-OFDM Systems

  • Yesilyurt, Ugur;Ertug, Ozgur
    • ETRI Journal
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    • v.40 no.2
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    • pp.218-226
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    • 2018
  • Multiuser detection (MUD) and channel estimation techniques in space-division multiple-access aided orthogonal frequency-division multiplexing systems recently has received intensive interest in receiver design technologies. The maximum likelihood (ML) MUD that provides optimal performance has the cost of a dramatically increased computational complexity. The minimum mean-squared error (MMSE) MUD exhibits poor performance, although it achieves lower computational complexity. With almost the same complexity, an MMSE with successive interference cancellation (SIC) scheme achieves a better bit error rate performance than a linear MMSE multiuser detector. In this paper, hybrid ML-MMSE with SIC adaptive multiuser detection based on the joint channel estimation method is suggested for signal detection. The simulation results show that the proposed method achieves good performance close to the optimal ML performance at low SNR values and a low computational complexity at high SNR values.

Half-pel Accuracy Motion Estimation Algorithm using Selective Interpolation in the Wavelet Domain (웨이블릿 영역에서의 선택적인 보간에 의한 반화소 단위 움직임 추정)

  • 이경환;정영훈;황희철
    • Journal of Korea Multimedia Society
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    • v.6 no.1
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    • pp.40-47
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    • 2003
  • In this paper, we propose a new method for reducing the computational overhead of fine-to-coarse multi-resolution motion estimation (MRME) at the finest resolution level by searching for the region to consider motion vectors of the coarsest resolution subband. At this time, if half-pel accuracy motion estimation (HPAME) is used in the baseband where influence a lot of effect to the reconstructed image, we can have the motion vector exactly But, this method causes to higher computational overhead. So we suggest the method to the computational overhead by using selective interpolation. Experimental results show that the proposed algorithm gives better results than the traditional algorithms from image quality.

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A Development of Finish Drawing Automation System for Improving Efficiency on BIM based Estimation (BIM 기반 견적업무 효율성 증대를 위한 마감설계자동화 시스템 개발)

  • Kim, Seong-Ah;Kang, Myung-Ku;Shin, Tea-Hong;Chin, Sang-Yoon;Yoon, Su-Won;Choi, Cheol-Ho
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.429-434
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    • 2008
  • The objective of this paper is to introduce a project on developing Finish Drawing Automation System. The system aims to improve efficiency of the BIM-based estimation, which is realized by automatic derivation of three-dimensional geometry models of the finish details. First, overall workload differences between the drawing-based estimation methods and the BIM-based methods are analyzed. Second, an automated finish detail design method is proposed as a time-saving measure for the BIM-based estimation, as manual modeling accounts for the most time spent in the model-based estimation process. Finally, the proposed system is evaluated using a case of washboard design.

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Edge-Preserving and Adaptive Transmission Estimation for Effective Single Image Haze Removal

  • Kim, Jongho
    • International Journal of Internet, Broadcasting and Communication
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    • v.12 no.2
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    • pp.21-29
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    • 2020
  • This paper presents an effective single image haze removal using edge-preserving and adaptive transmission estimation to enhance the visibility of outdoor images vulnerable to weather and environmental conditions with computational complexity reduction. The conventional methods involve the time-consuming refinement process. The proposed transmission estimation however does not require the refinement, since it preserves the edges effectively, which selects one between the pixel-based dark channel and the patch-based dark channel in the vicinity of edges. Moreover, we propose an adaptive transmission estimation to improve the visual quality particularly in bright areas like sky. Experimental results with various hazy images represent that the proposed method is superior to the conventional methods in both subjective visual quality and computational complexity. The proposed method can be adopted to compose a haze removal module for realtime devices such as mobile devices, digital cameras, autonomous vehicles, and so on as well as PCs that have enough processing resources.

Estimation of Localized Structural Parameters Using Substructural Identification (부분구조 추정법을 이용한 국부구조계수추정)

  • 윤정방;이형진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1996.04a
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    • pp.119-126
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    • 1996
  • In this paper, a method of substructural identification is presented for the estimation of localized structural parameters. for this purpose, an auto-regressive and moving average with stochastic input (ARMAX) model is derived for the substructure to process the measurement data impaired by noises. The sequential prediction error method is used fer the estimation of unknown localized parameters. Using the substructural method, the number of unknown parameters can be reduced and the convergence and accuracy of estimation can be improved. For some substructures, the effect of the input excitation is expressed in terms of the responses at the inferences with the main structure, and substructural identification may be carried out without measuring the actual input excitation to the whole structure. Example analysis is carried out for idealized structural models of a multistory building and a truss bridge. The results indicate that the present method is effective and efficient for local damage estimation of complex structures.

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Fast Multiresolution Motion Estimation in Wavelet Transform Domain Using Block Classification and HPAME (블록 분류와 반화소 단위 움직임 추정을 이용한 웨이브릿 변환 영역에서의 계층적 고속 움직임 추정 방법)

  • Gwon, Seong-Geun;Lee, Seok-Hwan;Ban, Seung-Won;Lee, Geon-Il
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.39 no.2
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    • pp.87-95
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    • 2002
  • In this paper, we proposed a fast multi-resolution motion estimation(MRME) algorithm. This algorithm exploits the half-pixel accuracy motion estimation(HPAME) for exact motion vectors in the baseband and block classification for the reduction of bit amounts and computational loads. Generally, as the motion vector in the baseband are used as initial motion vector in the high frequency subbands, it has crucial effect on quality of the motion compensated image. For this reason, we exploit HPAME in the motion estimation for the baseband. But HPAME requires additional bit and computational loads so that we use block classification for the selective motion estimation in the high frequency subbands to compensate these problems. In result, we could reduce the bit rate and computational load at the similar image quality with conventional MRME. The superiority of the proposed algorithm was confirmed by the computer simulation.

Fast Motion Estimation Technique using Efficient Prediction of Motion Vectors (움직임 벡터의 효율적 예측을 이용한 고속 움직임 추정 기법)

  • Kim, Jongho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.945-949
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    • 2009
  • This paper proposes an enhanced motion estimation that is one of core parts affecting the coding performance and visual quality in video coding. Although the full search technique, which is the most basic method of the motion estimation, presents the best visual quality, its computational complexity is great, since the search procedures to find the best matched block with each block in the current frame are carried out for all points inside the search area. Thus, various fast algorithms to reduce the computational complexity and maintain good visual quality have been proposed. The PMVFAST adopted the MPEG-4 visual standard produces the visual quality near that by the full search technique with the reduced computational complexity. In this paper, we propose a new motion vector prediction method using median processing. The proposed method reduces the computational complexity for the motion estimation significantly. Experimental results show that the proposed algorithm is faster than the PMVFAST and better than the full search in terms of search speed and average PSNR, respectively.

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Estimation of moment and rotation of steel rack connections using extreme learning machine

  • Shariati, Mahdi;Trung, Nguyen Thoi;Wakil, Karzan;Mehrabi, Peyman;Safa, Maryam;Khorami, Majid
    • Steel and Composite Structures
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    • v.31 no.5
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    • pp.427-435
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    • 2019
  • The estimation of moment and rotation in steel rack connections could be significantly helpful parameters for designers and constructors in the initial designing and construction phases. Accordingly, Extreme Learning Machine (ELM) has been optimized to estimate the moment and rotation in steel rack connection based on variable input characteristics as beam depth, column thickness, connector depth, moment and loading. The prediction and estimating of ELM has been juxtaposed with genetic programming (GP) and artificial neural networks (ANNs) methods. Test outcomes have indicated a surpass in accuracy predicting and the capability of generalization in ELM approach than GP or ANN. Therefore, the application of ELM has been basically promised as an alternative way to estimate the moment and rotation of steel rack connection. Further particulars are presented in details in results and discussion.