scholarly journals A Hybrid Orthogonal Forward-Backward Pursuit Algorithm for Partial Fourier Multiple Measurement Vectors Problem

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Haiqiang Liu ◽  
Gang Hua ◽  
Aichun Zhu ◽  
Hongsheng Yin ◽  
Yonggang Xu
Keyword(s):  
Prior Knowledge ◽  
Prior Information ◽  
Matching Pursuit ◽  
Computing Time ◽  
Multiple Measurement ◽  
Multiple Measurement Vectors ◽  
Second Stage ◽  
Support Set ◽  
Simulation Results ◽  
Two Stages

In solving the partial Fourier Multiple Measurement Vectors (FMMV) problem, existing greedy pursuit algorithms such as Simultaneous Orthogonal Matching Pursuit (SOMP), Simultaneous Subspace Pursuit (SSP), Hybrid Matching Pursuit (HMP), and Forward-Backward Pursuit (FBP) suffer from low recovery ability or need sparsity as a prior information. This paper combines SOMP and FBP to propose a Hybrid Orthogonal Forward-Backward Pursuit (HOFBP) algorithm. As an iterative algorithm, each iteration of HOFBP consists of two stages. In the first stage, α indices selected by SOMP are added to the support set. In the second stage, the support set is shrank by removing β indices. The choice of α and β is critical to the performance of this algorithm. The simulation results showed that, by using proper parameters, HOFBP has better performance than other greedy pursuit algorithms at the expense of more computing time in some cases. HOFBP does not need sparsity as a prior knowledge.

Effect of Hygrothermal Transfer on Multilayer Walls Behavior, Assessment of Condensation Risk

2014 ◽  
Vol 1051 ◽  
pp. 647-655 ◽  
Author(s):  
Mohammed Yacine Ferroukhi ◽  
Rafik Belarbi ◽  
Karim Limam
Keyword(s):  
Material Properties ◽  
Moisture Transfer ◽  
Transfer Model ◽  
Construction Sector ◽  
Moisture Capacity ◽  
Second Stage ◽  
Hygrothermal Behavior ◽  
Multilayer Wall ◽  
Simulation Results ◽  
Two Stages

Good insulation of envelopes in new or rehabilitated buildings represents one of the major issues in reducing the energy consumption in the construction sector. In order to ensure better insulation, a material compatible with the wall must be chosen to guarantees both good thermal insulation and reduction of humidity risk.This study reviews the risks related to moisture, particularly those related to condensation one occurring in buildings. Two stages were conducted during the study. Firstly, a coupled heat, air and moisture transfer model in a multilayer wall was developed. This model took into account both the discontinuity at the interfaces between the wall layers and the evolution of material properties depending on the water content. Then, applications to assess hygrothermal behavior of multilayer walls and predict of condensation risk into them were examined.Secondly, a parametric study was achieved on hygrothermal properties of insulation materials. The objective of this second stage was to evaluate sensitivity magnitude of different material properties on hygrothermal behavior of multilayers walls.This study focused on the most influential thermal and hydric properties in hygrothermal transfer model. Thus, thermal conductivity for heat transfer, total moisture permeability and moisture capacity to hydric transfer were selected.Finally, simulation results were analyzed and conclusions were derived on the effect of key parameters on the hygrothermal behavior in the walls and the conditions causing condensation risk to increase.

Preprocessing of Coefficients for Reusable Continuous Wavelet Transform

2014 ◽  
Vol 1040 ◽  
pp. 975-979 ◽  
Author(s):  
Alexander A. Khamukhin ◽  
Alexey A. Khamukhin
Keyword(s):  
Wavelet Transform ◽  
Continuous Wavelet Transform ◽  
Computing Time ◽  
Continuous Wavelet ◽  
Wavelet Coefficients ◽  
Nonstationary Signal ◽  
Online Detection ◽  
Second Stage ◽  
Time Required ◽  
Two Stages

The division into two stages of the Continuous Wavelet Transform (CWT) computing is proposed. This is expedient in circumstances when CWT is repeated many times, e.g., for online detection of nonstationary signal singularities. It is shown that the preprocessing of wavelet coefficients in the first stage can significantly reduce computing time required in the second stage. The comparative estimation of the runtime reduction in the second stage of CWT calculation is deduced.

scholarly journals Application of genetic algorithm for problem of optimizing location and capacity of distributed generation considering distributed network reconfiguration

2018 ◽  
Vol 20 (K7) ◽  
pp. 5-14
Author(s):  
Linh Tung Nguyen ◽  
Thuan Thanh Nguyen ◽  
Trieu Ngoc Ton ◽  
Anh Viet Truong ◽  
Xuan Anh Nguyen
Keyword(s):  
Genetic Algorithm ◽  
Distributed Generation ◽  
Distribution Network ◽  
Network Reconfiguration ◽  
Distributed Network ◽  
Network Configuration ◽  
Second Stage ◽  
Simulation Results ◽  
Two Stages ◽  
Radial Network

This paper presents a method of determining the location and size of distributed generation (DG) considering to operate the configuration of distribution network to minimize the real power loss. The proposed method which is based on the genetic algorithm (GA) is divided into two stages. In the first stage, GA is used to optimize the location and size of DG in the mesh distribution network, while in the second stage, GA is used to determine the radial network configuration after installing DG. The simulation results on the 33-nodes and 69-nodes systems show that the proposed method can be an efficient method for the placing DG problem and that is considering to solve the problem of distribution network reconfiguration.

scholarly journals Research on Pattern Synthesis of Time Modulated Sparse Array Based on Discrete Variable Convex Optimization

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jing Tan ◽  
Jiawen Hu ◽  
Xikuan Dong ◽  
Hailin Li ◽  
Jianjiang Zhou
Keyword(s):  
Convex Optimization ◽  
Discrete Variable ◽  
Central Frequency ◽  
Pattern Synthesis ◽  
Time Modulation ◽  
Second Stage ◽  
Excitation Time ◽  
Simulation Results ◽  
Two Stages ◽  
Full Utilization

Effective resource utilization is an important problem in the application of array, especially for the new time modulated array. Considering the problem of full utilization of array elements in time modulated array, a sparse optimization algorithm based on discrete variable convex optimization is proposed in this paper. The pattern optimization of equal excitation time modulation array is realized in two stages: In the first stage, the number of working array elements is as low as possible under the condition of suppressing the sidelobe of the central frequency. In the second stage, the sideband is suppressed by iterative convex optimization. The numerical simulation results are compared with other methods to verify the effectiveness of the proposed method in pattern optimization of equal excitation time modulation array. Finally, the optimization performance of the algorithm with different array parameters is verified.

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