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( Zhiyong Liu ),( Qinyu Zhang ),( Liwei Mu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.9
In this paper, an adjustable multiple relay selection (MRS) scheme for cooperative communication with amplify-and-forward (AF) relay under frequency selective channels is proposed. In the proposed scheme, the relays are ordered firstly by the steady-state mean square error (MSE), then the relays are sequentially selected out from N relays and the number of cooperating relays is adjusted dynamically according to the steady-state mean square joint error (MSJE). The aim of this work is to dynamically estimate the optimum number No of cooperating relays. Optimum means the minimum number of cooperating relays, No, achieving the minimum level of steady-state MSJE. Numerical results verify the analyses and show that the scheme can adaptively adjust the number of cooperating relays, and outperform conventional relay selection schemes. Hence, the proposed scheme provides better tradeoff between BER performance and spectral efficiency and to save more energy in cooperative wireless networks.
Zhiyong Zhang,Yiming Wang,Guangyi Liu,Sheng Liu,Jun Liu,Xianglin Yang 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.92 No.-
3-Amyl-4-amino-1,2,4-triazole-5-thione (AATT) reacted with Cu2+ or Pb2+ ions in aqueous solutions toform CuAATT and Pb(AATT)2 complexes and their solubility product constants were measured as 10 16.17and 10-20.60, respectively. In the moderately-alkaline media, both chalcopyrite and galena chemisorbedAATT on to their surfaces, and the adsorption amount of AATT on chalcopyrite was bigger than that ongalena, which rendered a stronger hydrophobization toward chalcopyrite. While under the high-alkalinepulp, AATT only chemisorbed on chalcopyrite, not on galena. The micro-flotationfindings indicated thatAATT was a favorable collector forflotation enrichment of chalcopyrite and galena at pH <11.0, andrealized an efficientflotation separation of chalcopyrite from galena under pH>11.5. The CuAATTcomplexwas more insoluble than Pb(AATT)2, which implied a stronger affinity of AATT toward chalcopyrite thangalena and returned their selectiveflotation separation at the high-alkaline condition.
An Exponential Smoothing Adaptive Failure Detector in the Dual Model of Heartbeat and Interaction
Zhiyong Yang,Chunlin Li,Yanpei Liu,Yunchang Liu,Lijun Xu 한국정보과학회 2014 Journal of Computing Science and Engineering Vol.8 No.1
In this paper, we propose a new implementation of a failure detector. The implementation uses a dual model of heartbeat and interaction. First, the heartbeat model is adopted to shorten the detection time, if the detection process does not receive the heartbeat message in the expected time. The interaction model is then used to check the process further. The expected time is calculated using the exponential smoothing method. Exponential smoothing can be used to estimate the next arrival time not only in the random data, but also in the data of linear trends. It is proven that the new detector in the paper can eventually be a perfect detector.
A Modified Adaptive Sparse Channel Estimator for OFDM Systems Based On Singular Value Decomposition
Liu Zhiyong,Wang Yiron,Liu Weicai 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.11
In this paper, a modified adaptive sparse channel estimator based on singular value decomposition (SVD) for OFDM systems is proposed. The conventional adaptive sparsity matching pursuit (ASMP) based compressive channel estimation has bad anti-noise performance, although not needing the information of sparsity. Because using the SVD to modify the measurement matrix of CS can improve the robustness to noise. So we use the SVD to modify the measurement matrix of ASMP based compressive channel estimation. The proposed channel estimation has better robustness to noise and low error. The simulation results show that comparing with ASMP based compressive channel estimation, the proposed algorithm has 1 dB gain at MSE and 1.3 dB gain at BER.
( Zhiyong Liu ),( Yinghua Wang ),( Lizhong Song ),( Yinyin Wang ),( Fusheng Dai ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.1
In this paper, we propose a joint adaptive combining and variable tap-length multiuser detector (MUD) for amplify-and-forward (AF) underwater acoustic cooperative interleave-division multiple access (IDMA) communication system. The proposed MUD jointly realizes tap-length adjustment, adaptive combining, and multiuser detection. In contrast to the existing methods, the proposed detector can adaptively combine the received signals from different nodes at destination, and does not need the assumption that full and perfect channel state information (CSI) of all the links at the receiver is known. Moreover, the proposed detector can adaptively adjust the tap coefficient vector and tap-length of each branch according to the specific channel profile of each branch. Simulation results validate the feasibility and show the advantages of the proposed detector against existing counterparts.
Study on Deformation of Closed-Cell Aluminum Foam in Different Solid–Liquid–Gas Coexisting State
Zhiyong Liu,Ying Cheng,Yanxiang Li,Ningzhen Wang,Xu Zhou 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.3
The deformation of closed-cell aluminum foam (CAF) in different solid–liquid–gas coexisting state was studied in thispaper. The results showed that the most suitable temperature of the CAF deformation was about 635 °C, which made theCAF have maximum deformation, but its characteristic parameters changed slightly. Moreover, the multi-grain cell wall andsmall size cell were helpful to the CAF deformation in the solid–liquid–gas coexisting state. When the CAF deformed at635 °C, the inter-granular solidification microstructure and part of the primary α-Al grain were melted into liquid. The fixedor inter-locked primary α-Al grain was released and changed into the distributed discretely near-spherical grain, making thecell wall have good thixotropy. At the same time, the gas pressure in the cell was recovered to the foaming stage, so the gaspressure could be close to the flow stress of cell wall. During the CAF deformation in the solid–liquid–gas coexisting state,the cell wall deformed in thixotropic under the supporting and coordinating of the gas pressure in the cell, meanwhile, thecell was moved following the cell wall deformation. Therefore, the CAF deformation was affected by the types of the cellwalls and the cell size.
Zhiyong Liu,Weimin Mao,Tan Wan,Guotao Cui,Weipan Wang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7
The semi-solid A380 aluminum alloy slurry prepared by water-cooling serpentine channel and its rheo-diecasting werestudied in this paper. The result showed that the pouring temperature and cooling water fow rate had a signifcant efect onthe semi-solid slurry. When the pouring temperature decreased from 670 to 610 °C, the average grain diameter and shapefactor of the primary α-Al grains decreased from 64 to 47 µm and increased from 0.74 to 0.82, respectively, but the mass ofsemi-solid slurry blocked in channel increased. With the cooling water fow rate increasing from 0 to 1000 L/h, the semisolid slurry frstly got optimized and then deteriorated. Under the condition of the same die casting process parameters, therheo-diecastings produced by the semi-solid slurry prepared through water-cooled serpentine channel had higher mechanicalproperties than those of the traditional die castings.
Liu Yang,Yang An,Bin Dai,Xuhong Guo,Zhiyong Liu,Banghua Peng 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2
Novel, visible light driven CNTs-TiO2@AgI hybrid materials were synthesized by a simple solvothermaldissolution- precipitation method, during which the acid vapor treated carbon nanotubes (CNTs) as template, AgI as sensitizer and TiO2 as the bridge unified them to form a ternary composite. The morphology and chemical components of as-prepared samples were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD and XPS characterizations indicated that anatase TiO2 and crystal AgI co-existed in the composite. HRTEM demonstrated CNTs were decorated with well-dispersed AgI and TiO2 nanoparticles (NPs), and TiO2 had an intimate connection with both AgI and CNTs. Diffusive reflectance UV-vis spectroscopy of CNTs-TiO2@AgI nanocomposite was extended to the whole UV-visible region due to adding of CNTs and AgI NPs. Degradation of Rhodamine B (RhB) polluted water using CNTs-TiO2@AgI NPs was carried out under visible light irradiation, and it showed higher degradation efficiency than CNTs-TiO2, TiO2@AgI, and CNTs@AgI NPs. The primary reason for the enhanced photocatalytic property was attributed to the synergic effect in CNTs-TiO2@AgI, which included the good adsorption ability and electrical conductivity of CNTs as well as the intimate connection and hetero-junctions among AgI, TiO2, and CNTs. Meanwhile, the as-prepared hybrid materials can be easily separated and reclaimed from the liquid phase, and the recycling tests indicated CNTs-TiO2@AgI had renewable performance.
Study on Formation of Microstructure in Rheo-Diecastings of Semi-Solid A380 Aluminum Alloy Slurry
Zhiyong Liu,Guotao Cui,Tan Wan,Weimin Mao 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7
The formation of the microstructure in the rheo-diecastings were studied by the experiment of rheo-diecasting with semi-solidA380 Aluminum alloy slurry. The results show that the grain diameter and shape factor of primary α-Al grains decreased andincreased along the rheo-diecasting direction, respectively, making the primary α-Al grains gradually distributing uniformly. The combination of injection pressure and narrow gate of the runner and ingate was the main reason for the evolution of theprimary α-Al grains, moreover, the collision and friction among primary α-Al grains during the flling were helpful for therefnement and spheroidization of the primary α-Al grains. The residual liquid solidifed into the secondary solidifcationmicrostructure accompanied by the evolution of the primary α-Al grains. The accumulation of the fragments of the primaryα-Al grains, the secondary α2-Al nuclei or grains which formed in previous positions, the efective nucleation rate of theresidual liquid, and the collision and fraction among the secondary α2-Al grains and between the secondary α2-Al grainand the primary α-Al grains made the secondary solidifcation microstructure of the residual liquid present multiplex andcomplicate characteristics.