• Title/Summary/Keyword: approximate algorithm

검색결과 701건 처리시간 0.032초

Structure of the Mixed Neural Networks Based On Orthogonal Basis Functions (직교 기저함수 기반의 혼합 신경회로망 구조)

  • Kim, Seong-Joo;Seo, Jae-Yong;Cho, Hyun-Chan;Kim, Seong-Hyun;Kim, Hong-Tae
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • 제39권6호
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    • pp.47-52
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    • 2002
  • The wavelet functions are originated from scaling functions and can be used as activation function in the hidden node of the network by deciding two parameters such as scale and center. In this paper, we would like to propose the mixed structure. When we compose the WNN using wavelet functions, we propose to set a single scale function as a node function together. The properties of the proposed structure is that while one scale function approximates the target function roughly, the other wavelet functions approximate it finely. During the determination of the parameters, the wavelet functions can be determined by the global search algorithm such as genetic algorithm to be suitable for the suggested problem. Finally, we use the back-propagation algorithm in the learning of the weights.

Beam Forming Study and Optimum Antenna Location Selection for Wideband Conformal Array Antenna (광대역 컨포멀 배열 안테나를 위한 빔 형성 연구 및 최적 소자 위치 선정)

  • Jung, Sang-Hoon;Lee, Kang-In;Nam, Sang-Wook;Chung, Young-Seek;Yoon, Young-Joong;Ryu, Hong-Kyun;Jung, Hyun-Kyo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • 제27권2호
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    • pp.138-146
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    • 2016
  • This paper proposes an optimum beam forming of conformal array antenna by using LSM(Least Squares Method) and GA(Genetic Algorithm). The weights which approximate conformal array antenna beam pattern to linear array antenna beam pattern have been evaluated by applying LSM. Also, the optimum locations of conformal array antenna which form wideband optimum beam pattern have been obtained by using GA. The proposed method is applied to a problem of Bezier platform array antenna for a verification purpose.

Precise Indoor Positioning Algorithm for Energy Efficiency Based on BLE Fingerprinting (에너지 효율을 고려한 BLE 핑거프린팅 기반의 정밀 실내 측위 알고리즘)

  • Lee, Dohee;Lee, Jaeho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제41권10호
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    • pp.1197-1209
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    • 2016
  • As Indoor Positioning System demands due to increased penetration and utilization of smart device, Indoor Positioning System using Wi-Fi or BLE(Bluetooth Low Energy) beacon takes center stage. In this paper, a terminal location of the user is calculated through Microscopic Trilateration using RSSI based on BLE. In the next step, a fingerprinting map appling approximate value of Microscopic Trilateration increases an efficiency of computation amount and energy for Indoor Positioning System. I suggest Indoor Positioning Algorithm based on BLE fingerprinting considering efficiency of energy by conducting precise Trilateration that assure user's terminal position by using AP(Access Point) surrounding targeted fingerprinting cells. And This paper shows experiment and result based on An Suggesting Algorithm in comparison with a fingerprinting based on BLE and Wi-Fi that be used for Indoor Positioning System.

Study on the termination rule in the iterative image restoration algorithm (반복 복원 알고리듬에서의 종료 규칙에 관한 연구)

  • 문태진;김인겸;박규태
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제22권8호
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    • pp.1803-1813
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    • 1997
  • The goal of image restoration is to remove the degradations in a way that the resrored image will best approximate the original image. This can be done by the iterative regularized image restoration method. In any iterative image restoration algorithm, using a "better" termination rule results in both "better" quality of ther restored image and "less" computation, and hence, "faster" and "simp;er" practical system. Therefore, finding a better termmination rule for an iterative image restoration algorithm has been an interesting and improtant question for many researchers in the iterative image restoration. In these reasons, the new termination rule using the estimated distance between the original image and the restored image is proposed inthis paper. Noise suppression parameter(NSP) and the rule for estimating NSP with the noise variance are also proposed. The experimental results shows that the proposed termination rule is superior to the conventional methods.

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Iterative Low Rank Approximation for Image Denoising (영상 잡음 제거를 위한 반복적 저 계수 근사)

  • Kim, Seehyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • 제25권10호
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    • pp.1317-1322
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    • 2021
  • Nonlocal similarity of natural images leads to the fact that a patch matrix whose columns are similar patches of the reference patch has a low rank. Images corrupted by additive white Gaussian noises (AWGN) make their patch matrices to have a higher rank. The noise in the image can be reduced by obtaining low rank approximation of the patch matrices. In this paper, an image denoising algorithm is proposed, which first constructs the patch matrices by combining the similar patches of each reference patch, which is a part of the noisy image. For each patch matrix, the proposed algorithm calculates its low rank approximate, and then recovers the original image by aggregating the low rank estimates. The simulation results using widely accepted test images show that the proposed denoising algorithm outperforms four recent methods.

Analysis on Optimal Approach of Blind Deconvolution Algorithm in Chest CT Imaging (흉부 컴퓨터단층촬영 영상에서 블라인드 디컨볼루션 알고리즘 최적화 방법에 대한 연구)

  • Lee, Young-Jun;Min, Jung-Whan
    • Journal of radiological science and technology
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    • 제45권2호
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    • pp.145-150
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    • 2022
  • The main purpose of this work was to restore the blurry chest CT images by applying a blind deconvolution algorithm. In general, image restoration is the procedure of improving the degraded image to get the true or original image. In this regard, we focused on a blind deblurring approach with chest CT imaging by using digital image processing in MATLAB, which the blind deconvolution technique performed without any whole knowledge or information as to the fundamental point spread function (PSF). For our approach, we acquired 30 chest CT images from the public source and applied three type's PSFs for finding the true image and the original PSF. The observed image might be convolved with an isotropic gaussian PSF or motion blurring PSF and the original image. The PSFs are assumed as a black box, hence restoring the image is called blind deconvolution. For the 30 iteration times, we analyzed diverse sizes of the PSF and tried to approximate the true PSF and the original image. For improving the ringing effect, we employed the weighted function by using the sobel filter. The results was compared with the three criteria including mean squared error (MSE), root mean squared error (RMSE) and peak signal-to-noise ratio (PSNR), which all values of the optimal-sized image outperformed those that the other reconstructed two-sized images. Therefore, we improved the blurring chest CT image by using the blind deconvolutin algorithm for optimal approach.

A DNA Index Structure using Frequency and Position Information of Genetic Alphabet (염기문자의 빈도와 위치정보를 이용한 DNA 인덱스구조)

  • Kim Woo-Cheol;Park Sang-Hyun;Won Jung-Im;Kim Sang-Wook;Yoon Jee-Hee
    • Journal of KIISE:Databases
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    • 제32권3호
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    • pp.263-275
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    • 2005
  • In a large DNA database, indexing techniques are widely used for rapid approximate sequence searching. However, most indexing techniques require a space larger than original databases, and also suffer from difficulties in seamless integration with DBMS. In this paper, we suggest a space-efficient and disk-based indexing and query processing algorithm for approximate DNA sequence searching, specially exact match queries, wildcard match queries, and k-mismatch queries. Our indexing method places a sliding window at every possible location of a DNA sequence and extracts its signature by considering the occurrence frequency of each nucleotide. It then stores a set of signatures using a multi-dimensional index, such as R*-tree. Especially, by assigning a weight to each position of a window, it prevents signatures from being concentrated around a few spots in index space. Our query processing algorithm converts a query sequence into a multi-dimensional rectangle and searches the index for the signatures overlapped with the rectangle. The experiments with real biological data sets revealed that the proposed method is at least three times, twice, and several orders of magnitude faster than the suffix-tree-based method in exact match, wildcard match, and k- mismatch, respectively.

Double Precision Integer Divider Using Multiplier (곱셈기를 사용한 배정도 정수 나눗셈기)

  • Song, Hong-Bok;Cho, Gyeong-Yeon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • 제14권3호
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    • pp.637-647
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    • 2010
  • This paper suggested an algorithm that uses a multiplier, 'w bit $\times$ w bit = 2w bit', to process $\frac{N}{D}$ integer division of 2w bit integer N and w bit integer D. An algorithm suggested of the research, when the divisor D is '$D=0.d{\times}2^L$, 0.5 < 0.d < 1.0', approximate value of $\frac{1}{D}$, '$1.g{\times}2^{-L}$', which satisfies '$0.d{\times}1.g=1+e$, e < $2^{-w}$', is defined as over reciprocal number and the dividend N is segmented in small word more than 'w-3' bit, and partial quotient is calculated by multiplying over reciprocal number in each segmented word, and quotient of double precision integer division is evaluated with sum of partial quotient. The algorithm suggested in this paper doesn't require additional correction, because it can calculate correct reciprocal number. In addition, this algorithm uses only multiplier, so additional hardware for division is not required to implement microprocessor. Also, it shows faster speed than the conventional SRT algorithm. In conclusion, results from this study could be used widely for implementation SOC(System on Chip) and etc. which has been restricted to microprocessor and size of the hardware.

Algorithm for a Minimum Linear Arrangement(MinLA) of Lattice Graph (격자 그래프의 최소선형배열 알고리즘)

  • Sang-Un Lee
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • 제24권2호
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    • pp.105-111
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    • 2024
  • This paper deals with the minimum linear arrangement(MinLA) of a lattice graph, to which an approximate algorithm of linear complexity O(n) remains as a viable solution, deriving the optimal MinLA of 31,680 for 33×33 lattice. This paper proposes a partitioning arrangement algorithm of complexity O(1) that delivers exact solution to the minimum linear arrangement. The proposed partitioning arrangement algorithm could be seen as loading boxes into a container. It firstly partitions m rows into r1,r2,r3 and n columns into c1,c2,c3, only to obtain 7 containers. Containers are partitioning with a rule. It finally assigns numbers to vertices in each of the partitioned boxes location-wise so as to obtain the MinLA. Given m,n≥11, the size of boxes C2,C4,C6 is increased by 2 until an increase in the MinLA is detected. This process repeats itself 4 times at maximum given m,n≤100. When tested to lattice in the range of 2≤n≤100, the proposed algorithm has proved its universal applicability to lattices of both m=n and m≠n. It has also obtained optimal results for 33×33 and 100×100 lattices superior to those obtained by existing algorithms. The minimum linear arrangement algorithm proposed in this paper, with its simplicity and outstanding performance, could therefore be also applied to the field of Very Large Scale Integration circuit where m,n are infinitely large.

Efficiency Evaluation of Genetic Algorithm Considering Building Block Hypothesis for Water Pipe Optimal Design Problems (상수관로 최적설계 문제에 있어 빌딩블록가설을 고려한 유전 알고리즘의 효율성 평가)

  • Lim, Seung Hyun;Lee, Chan Wook;Hong, Sung Jin;Yoo, Do Guen
    • Journal of the Korea Academia-Industrial cooperation Society
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    • 제21권5호
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    • pp.294-302
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    • 2020
  • In a genetic algorithm, computer simulations are performed based on the natural evolution process of life, such as selection, crossover, and mutation. The genetic algorithm searches the approximate optimal solution by the parallel arrangement of Schema, which has a short definition length, low order, and high adaptability. This study examined the possibility of improving the efficiency of the optimal solution by considering the characteristics of the building block hypothesis, which are one of the key operating principles of a genetic algorithm. This study evaluated the efficiency of the optimization results according to the gene sequence for the implementation in solving problems. The optimal design problem of the water pipe was selected, and the genetic arrangement order reflected the engineering specificity by dividing into the existing, the network topology-based, and the flowrate-based arrangement. The optimization results with a flowrate-based arrangement were, on average, approximately 2-3% better than the other batches. This means that to increase the efficiency of the actual engineering optimization problem, a methodology that utilizes clear prior knowledge (such as hydraulic properties) to prevent such excellent solution characteristics from disappearing is essential. The proposed method will be considered as a tool to improve the efficiency of large-scale water supply network optimization in the future.