Dimension-reduction simulation of stochastic wind velocity fields by two continuous approaches

Zhangjun Liu,Chenggao He,Zenghui Liu,Hailin Lu 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.6

In this study, two original spectral representations of stationary stochastic fields, say the continuous proper orthogonal decomposition (CPOD) and the frequency-wavenumber spectral representation (FWSR), are derived from the Fourier-Stieltjes integral at first. Meanwhile, the relations between the above two representations are discussed detailedly. However, the most widely used conventional Monte Carlo schemes associated with the two representations still leave two difficulties unsolved, say the high dimension of random variables and the incompleteness of probability with respect to the generated sample functions of the stochastic fields. In view of this, a dimension-reduction model involving merely one elementary random variable with the representative points set owing assigned probabilities is proposed, realizing the refined description of probability characteristics for the stochastic fields by generating just several hundred representative samples with assigned probabilities. In addition, for the purpose of overcoming the defects of simulation efficiency and accuracy in the FWSR, an improved scheme of non-uniform wavenumber intervals is suggested. Finally, the Fast Fourier Transform (FFT) algorithm is adopted to further enhance the simulation efficiency of the horizontal stochastic wind velocity fields. Numerical examples fully reveal the validity and superiority of the proposed methods.

Single Relay Selection for Bidirectional Cooperative Networks with Physical-Layer Network Coding

Yingting Liu,Hailin Zhang,Leifang Hui,Quanyang Liu,Xiaofeng Lu 한국전자통신연구원 2012 ETRI Journal Vol.34 No.1

To serve the growing demand of the bidirectional information exchange, we propose a single relay selection (RS) scheme for physical-layer network coding (PNC) in a bidirectional cooperative network consisting of two sources and multiple relays. This RS scheme selects a single best relay by maximizing the bottleneck of the capacity region of both information flows in the bidirectional network. We show that the proposed RS rule minimizes the outage probability and that it can be used as a performance benchmark for any RS rules with PNC. We derive a closed-form exact expression of the outage probability for the proposed RS rule and show that it achieves full diversity gain. Finally, numerical results demonstrate the validity of our analysis.

Current utilization of waste biomass as filler for wood adhesives: A review

Jinming Liu,Yongfeng Li,Hailin Mo,Enjun Xie,Jianlin Fang,Weixing Gan 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

Filler is one of the most important additives for wood adhesives. The introduction of filler offers variousfunctions for wood adhesives, such as the increase of initial viscosity, the decrease of permeability, theimprovement of bonding strength, and the reduction of production cost. However, flour, a grain resource,is widely used as a filler that is added to polymers in the production of wood-based panels. As a result, alarge number of edible resources are wasted every year. Waste biomass that biomass residues are abandonedin nature are a promising filler that can be used to replace flour. The utilization of waste biomass asfiller for wood adhesives to prepare wood-based panels not only improves its mechanical strength, butalso reduces formaldehyde emissions. However, most waste biomass shows disappointing prepressingproperties. Advances in the use of waste biomass as an alternative filler for wood adhesives werereviewed. In addition, the current limitations and future prospects of waste biomass were discussed. Recycling waste biomass is a useful way to avoid the enormous amount of waste generated by differentindustries and control environmental pollution. It contributes to the practical development of circulareconomy.

A Novel Structural Optimization Method and a Case Study Based on a CHS X-Joint

Xingqi Liu,Weitong Yi,Hailin Sun,Lei Zhu,Xi Chen 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.4

In this paper, a new structural optimization method, “percentage structure optimization”, is presented. This method is obtained by using fi nite element method (FEM) to reduce a specifi c proportion of the stress ineffi cient element reduction, which is called the "structural optimization percentage index". In addition, an evaluation index of the optimized structure, “economic benefi t index”, is introduced. Compared with the existing structural optimization methods, the optimization process is smoother and the results are more controllable. Moreover, the method of evaluating the optimization results through the “economic benefi t index” pays more attention to the economic benefi ts of the project, and can achieve the balance between the minimization of material and the detention of bearing capacity to maximize the economic benefi ts. On the basis of the existing experiment, using ANSYS 17.0 software, two Circular Hollow Sections (CHS) X-joints are optimized by "structural optimization percentage index" of 5, 10 and 15%, and "economic benefi t index" is adopted as the judgment condition of the optimization results. The results show that the method can not only guarantee the bearing capacity, but also save materials as much as possible, and verify the reliability of the new structural optimization method.

Distributed Space-Time Coding for Full-Duplex Asynchronous Cooperative Communications

Yi Liu,Xiang-Gen Xia,Hailin Zhang IEEE 2012 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.11 No.7

<P>In this paper, we propose two distributed linear convolutional space-time coding (DLC-STC) schemes for full-duplex (FD) asynchronous cooperative communications. The DLC-STC Scheme 1 is for the case of the complete loop channel cancellation, which achieves the full asynchronous cooperative diversity. The DLC-STC Scheme 2 is for the case of the partial loop channel cancellation and amplifying, where some loop signals are used as the self-coding instead of treated as interference to be directly cancelled. We show this scheme can achieve full asynchronous cooperative diversity. We then evaluate the performance of the two schemes when loop channel information is not accurate and present an amplifying factor control method for the DLC-STC Scheme 2 to improve its performance with inaccurate loop channel information. Simulation results show that the DLC-STC Scheme 1 outperforms the DLC-STC Scheme 2 and the delay diversity scheme if perfect or high quality loop channel information is available at the relay, while the DLC-STC Scheme 2 achieves better performance if the loop channel information is imperfect.</P>

Disheveled-associated activator of morphogenesis 2 promotes invasion of colorectal cancer by activating PAK1 and promoting MMP7 expression

Chen Aimei,Liu Zhiqiang,Wu Quanyan,Li Hailin 한국유전학회 2021 Genes & Genomics Vol.43 No.8

Background Disheveled-associated activator of morphogenesis (DAAM) family, including DAAM1 and DAAM2, is key regulators in Wnt signaling pathway. Although the oncogenic role of Wnt signaling pathway in colorectal cancer (CRC) was investigated in several lines, the expression and function of DAAM in CRC are still obscure. Objective To investigate the expression and function of DAAM in CRC. Methods DAAM1 and DAAM2 expression in high grade dysplasia (HGD), CRCs and corresponding adjacent tissues were detected with qRT-PCR and immunohistochemistry (IHC). The prognostic signifcance of DAAM1/2 were estimated with univariate and multivariate analyses. Moreover, the correlations between clinicopathological factors and DAAM were evaluated with the χ2 test. With experiments in vitro, we investigated the function of DAAM2 in CRC cell proliferation and invasion, and investigated the underlying mechanism of how DAAM2 facilitated CRC invasion. Results DAAM2, instead of DAAM1, was substantially up-regulated in CRCs compared with paired adjacent normal tissues and HGDs. The ratio of high DAAM1 and DAAM2 expression accounted for 44.83% and 46.31%, respectively. High DAAM2, instead of DAAM1, was a risk factor indicating an unfavorable prognosis of CRC. In multivariate analysis, high DAAM2 was identifed as an independent prognostic biomarker of CRC predicting poor prognosis. With experiments in vitro, DAAM2 promoted invasion of CRC cells via activating PAK1 and promoting the expression of MMP7, suggesting an essential role of DAAM2 in CRC invasion. Conclusions High expression of DAAM2, instead of DAAM1, indicated an unfavorable prognosis of CRC independently, which suggested that detecting DAAM2 can help defne the high-risk patients. DAAM2 activated PAK1 and promoted MMP7 expression and facilitated the invasion of CRC cells, indicating that DAAM2 may be a potential drug target of CRC.

Wavelet-domain Image Restoration Model Based on Variation Regularization

Caixia Li,Chanjuan Liu,Hailin Zou 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.2

A Rendezvous Node Selection and Routing Algorithm for Mobile Wireless Sensor Network

( Yifan Hu ),( Yi Zheng ),( Xiaoming Wu ),( Hailin Liu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.10

Efficient rendezvous node selection and routing algorithm (RNSRA) for wireless sensor networks with mobile sink that visits rendezvous node to gather data from sensor nodes is proposed. In order to plan an optimal moving tour for mobile sink and avoid energy hole problem, we develop the RNSRA to find optimal rendezvous nodes (RN) for the mobile sink to visit. The RNSRA can select the set of RNs to act as store points for the mobile sink, and search for the optimal multi-hop path between source nodes and rendezvous node, so that the rendezvous node could gather information from sensor nodes periodically. Fitness function with several factors is calculated to find suitable RNs from sensor nodes, and the artificial bee colony optimization algorithm (ABC) is used to optimize the selection of optimal multi-hop path, in order to forward data to the nearest RN. Therefore the energy consumption of sensor nodes is minimized and balanced. Our method is validated by extensive simulations and illustrates the novel capability for maintaining the network robustness against sink moving problem, the results show that the RNSRA could reduce energy consumption by 6% and increase network lifetime by 5% as comparing with several existing algorithms.