• Title/Summary/Keyword: weighted function

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Smart modified repetitive-control design for nonlinear structure with tuned mass damper

  • ZY Chen;Ruei-Yuan Wang;Yahui Meng;Timothy Chen
    • Steel and Composite Structures
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    • v.46 no.1
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    • pp.107-114
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    • 2023
  • A new intelligent adaptive control scheme was proposed that combines observer disturbance-based adaptive control and fuzzy adaptive control for a composite structure with a mass-adjustable damper. The most important advantage is that the control structures do not need to know the uncertainty limits and the interference effect is eliminated. Three adjustable parameters in LMI are used to control the gain of the 2D fuzzy control. Binary performance indices with weighted matrices are constructed to separately evaluate validation and training performance using the revalidation learning function. Determining the appropriate weight matrix balances control and learning efficiency and prevents large gains in control. It is proved that the stability of the control system can be ensured by a linear matrix theory of equality based on Lyapunov's theory. Simulation results show that the multilevel simulation approach combines accuracy with high computational efficiency. The M-TMD system, by slightly reducing critical joint load amplitudes, can significantly improve the overall response of an uncontrolled structure.

Identifications of Source Locations for Atmospheric Total Gaseous Mercury Using Hybrid Receptor Models (Hybrid receptor model을 이용한 대기 중 총 가스상 수은의 오염원 위치 추정 연구)

  • Lee, Yong-Mi;Yi, Seung-Muk;Heo, Jong-Bae;Hong, Ji-Hyoung;Lee, Suk-Jo;Yoo, Chul
    • Journal of Environmental Science International
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    • v.19 no.8
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    • pp.971-981
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    • 2010
  • The objectives of this study were to measure ambient total gaseous mercury (TGM) concentrations in Seoul, to analyze the characteristics of TGM concentration, and to identify of possible source areas for TGM using back-trajectory based hybrid receptor models like PSCF (Potential Source Contribution Function) and RTWC (Residence Time Weighted Concentration). Ambient TGM concentrations were measured at the roof of Graduate School of Public Health building in Seoul for a period of January to October 2004. Average TGM concentration was $3.43{\pm}1.17\;ng/m^3$. TGM had no notable pattern according to season and meteorological phenomena such as rainfall, Asian dust, relative humidity and so on. Hybrid receptor models incorporating backward trajectories including potential source contribution function (PSCF) and residence time weighted concentration (RTWC) were performed to identify source areas of TGM. Before hybrid receptor models were applied for TGM, we analysed sensitivities of starting height for HYSPLIT model and critical value for PSCF. According to result of sensitivity analysis, trajectories were calculated an arrival height of 1000 m was used at the receptor location and PSCF was applied using average concentration as criterion value for TGM. Using PSCF and RTWC, central and eastern Chinese industrial areas and the west coast of Korea were determined as important source areas. Statistical analysis between TGM and GEIA grided emission bolsters the evidence that these models could be effective tools to identify possible source area and source contribution.

A linear program approach for a global optimization problem of optimizing a linear function over an efficient set (글로벌최적화 문제인 유효해집합 위에서의 최적화 문제에 대한 선형계획적 접근방법)

  • 송정환
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2000.04a
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    • pp.53-56
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    • 2000
  • The problem ( Ρ ) of optimizing a linear function d$\^$T/x over the set of efficient set for a multiple objective linear program ( Μ ) is difficult because the efficient set is nonconvex. There some interesting properties between the objective linear vector d and the matrix of multiple objectives C and those properties lead us to establish criteria to solve ( Ρ ) with a linear program. In this paper we investigate a system of the linear equations C$\^$T/${\alpha}$=d and construct two linearly independent positive vectors ${\mu}$, ν such that ${\alpha}$=${\mu}$-ν. From those vectors ${\mu}$, ν, solving an weighted sum linear program for finding an efficient extreme point for the ( Μ ) is a way to get an optimal solution ( Ρ ). Therefore our theory gives an easy way of solving nonconvex program ( Ρ ) with a weighted sum linear program.

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Adaptive Interpolation for Intra Frames in H.264 Using Interference Function (H.264 인트라 프레임에서 방해함수를 이용한 적응적 보간)

  • Park Mi-Seon;Yoo Jae-Myeong;Toan Nguyen Dinh;Kim Ji-Soo;Son Hwa-Jeong;Lee Guee-Sang
    • The Journal of the Korea Contents Association
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    • v.6 no.10
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    • pp.107-113
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    • 2006
  • Error Concealment method for Intra frames in H.264 reconstructs the lost block by computing weighted average value of the boundary pixels of the neighboring blocks; up, bottom, left and right blocks. However a simple average of pixel values of the neighboring blocks for Intra frames in H.264 leads to excessive blurring and degrades the picture quality severely. To solve this problem, in this paper we estimate the dominant edge of lost block using the pixel values of the neighboring blocks and reconstruct the pixel values by choosing adaptive interpolation between directional interpolation and weighted average interpolation considering the result value of the interference function based on statistics. Finally directional interpolation method improves by determining the dominant edge direction considering the relation of the dominent edge and the edges of neighboring blocks. Experiments show improvement of picture quality of about $0.5{\sim}2.0dB$ compared with the method of H.264.

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Improving the Implementation Complexity of the Latency-Optimized Fair Queuing Algorithm (최적 레이턴시 기반 공정 큐잉 알고리즘의 구현 복잡도 개선)

  • Kim, Tae-Joon;Suh, Bong-Sue
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.6B
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    • pp.405-413
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    • 2012
  • WFQ(Weighted Fair Queuing) is the most popular fair queuing algorithm to guarantee the Quality-of-Service(QoS), but it has the inherent drawback of a poor resource utilization, particularly under the low rate traffic requiring a tight delay bound. It was recently identified that the poor utilization is mainly due to non-optimized latency of a traffic flow and then LOFQ(Latency-Optimized Fair Queuing) to overcome the drawback was introduced. The LOFQ algorithm, however, renews their optimal latencies for all flows whenever a new flow arrives, which results in the high implementation complexity of O($N^2$).This paper is to reduce thecomplexity to O(1). The proposed method is first to derive the optimal latency index function from the statistical QoS characteristics of the offered load, and then to simply calculate the optimal latency index of the arriving flow using the function.

A Study on Function Recognition of EMG Signal Using LPC Cepstrum Coefficients (LPC 켑스트럼 계수를 이용한 EMG 신호의 기능 인식에 관한 연구)

  • Wang, Sung-Moon;Chung, Tae-Yun;Choi, Yun-Ho;Byun, Youn-Shik;Park, Sang-Hui
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.2
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    • pp.126-134
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    • 1990
  • In this study, eight function discrimination and recognition of the EMG signal from the biceps and triceps of 4 subjects were executed, using the Euclidean and weighted cepstral distance measure with LPC cepstrum coefficients. In case of Euclidean cepstral distance measure, as the number of LPC cepstrum coefficients was increased in 8, 10, 12, 14 the recognition rates of functions are 94.69, 95.63, 96.56, and 96.88[%], respectively, but increasing rates of recognition were inclined to decrease. In case of weighted cepstral distance measure, when the number of LPC cepstrum coefficients was 8, 10, 12 and 14, the recognition rates of functions were 91.88, 95, 99.69, and 96.63[%], respectively.

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A Weighted Fuzzy Min-Max Neural Network for Pattern Classification (패턴 분류 문제에서 가중치를 고려한 퍼지 최대-최소 신경망)

  • Kim Ho-Joon;Park Hyun-Jung
    • Journal of KIISE:Software and Applications
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    • v.33 no.8
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    • pp.692-702
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    • 2006
  • In this study, a weighted fuzzy min-max (WFMM) neural network model for pattern classification is proposed. The model has a modified structure of FMM neural network in which the weight concept is added to represent the frequency factor of feature values in a learning data set. First we present in this paper a new activation function of the network which is defined as a hyperbox membership function. Then we introduce a new learning algorithm for the model that consists of three kinds of processes: hyperbox creation/expansion, hyperbox overlap test, and hyperbox contraction. A weight adaptation rule considering the frequency factors is defined for the learning process. Finally we describe a feature analysis technique using the proposed model. Four kinds of relevance factors among feature values, feature types, hyperboxes and patterns classes are proposed to analyze relative importance of each feature in a given problem. Two types of practical applications, Fisher's Iris data and Cleveland medical data, have been used for the experiments. Through the experimental results, the effectiveness of the proposed method is discussed.

Muti-Objective Design Optimization of Self-Compacting Concrete using CCD Experimental Design and Weighted Multiple Objectives Considering Cost-Effectiveness (비용효율을 고려한 자기 충전형 콘크리트의 CCD 실험설계법 및 가중 다목적성 기반 다목적설계최적화(MODO))

  • Do, Jeongyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.3
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    • pp.26-38
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    • 2020
  • Mixture design of self-compacting concrete is a typical multi-criteria decision making problem and conventional mixture designs are based on the low level engineering method like trials and errors through iteration method to satisfy the various requirements. This study concerns with performing the straightforward multiobjective design optimization of economic SCC mixture considering relative importances of the various requirements and cost-effectives of SCC. Total five requirements of 28day compressive strength, filling ability, segregation stability, material cost and mass were taken into consideration to prepare the objective function to be formulated in form of the weighted-multiobjective mixture design optimization problem. Economic SCC mixture computational design can be given in a rational way which considering material costs and the relative importances of the requiremets and from the result of this study it is expected that the development of SCC mixtue computational design and the consequent univeral concrete material design optimization methodology can be advanced.

Comparative analysis of spatial interpolation methods of PM10 observation data in South Korea (남한지역 PM10 관측자료의 공간 보간법에 대한 비교 분석)

  • Kang, Jung-Hyuk;Lee, Seoyeon;Lee, Seung-Jae;Lee, Jae-Han
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.24 no.2
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    • pp.124-132
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    • 2022
  • This study was aimed to visualize the spatial distribution of PM10 data measured at non-uniformly distributed observation sites in South Korea. Different spatial interpolation methods were applied to irregularly distributed PM10 observation data from January, 2019, when the concentration was the highest and in July, 2019, when the concentration was the lowest. Four interpolation methods with different parameters were used: Inverse Distance Weighted (IDW), Ordinary Kriging (OK), radial base function, and scattered interpolation. Six cases were cross-validated and the normalized root-mean-square error for each case was compared. The results showed that IDW using smoothing-related factors was the most appropriate method, while the OK method was least appropriate. Our results are expected to help users select the proper spatial interpolation method for PM10 data analysis with comparative reliability and effectiveness.

Analysis Method of X-Ray Diffraction Characteristic Values and Measured Strain for Steep Stress Gradient of Metal Material Surface Layer (금속재료 표면층의 급격한 응력구배에 대한 X-Ray회절 특성값과 측정된 변형률의 해석방법)

  • Chang-Suk Han;Chan-Woo Lee
    • Korean Journal of Materials Research
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    • v.33 no.2
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    • pp.54-62
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    • 2023
  • The most comprehensive and particularly reliable method for non-destructively measuring the residual stress of the surface layer of metals is the sin2ψ method. When X-rays were used the relationship of εφψ-sin2ψ measured on the surface layer of the processing metal did not show linearity when the sin2ψ method was used. In this case, since the effective penetration depth changes according to the changing direction of the incident X-ray, σφ becomes a sin2ψ function. Since σφ cannot be used as a constant, the relationship in εφψ-sin2ψ cannot be linear. Therefore, in this paper, the orthogonal function method according to Warren's diffraction theory and the basic profile of normal distribution were synthesized, and the X-ray diffraction profile was calculated and reviewed when there was a linear strain (stress) gradient on the surface. When there is a strain gradient, the X-ray diffraction profile becomes asymmetric, and as a result, the peak position, the position of half-maximum, and the centroid position show different values. The difference between the peak position and the centroid position appeared more clearly as the strain (stress) gradient became larger, and the basic profile width was smaller. The weighted average strain enables stress analysis when there is a strain (stress) gradient, based on the strain value corresponding to the centroid position of the diffracted X-rays. At the 1/5 Imax max height of X-ray diffraction, the position where the diffracted X-ray is divided into two by drawing a straight line parallel to the background, corresponds approximately to the centroid position.