This paper studies a dual-hop Simultaneous Wireless Information and Power Transfer(SWIPT)-based multi-relay network with a direct link.To achieve high throughput in the network,a novel protocol is first developed,in w...This paper studies a dual-hop Simultaneous Wireless Information and Power Transfer(SWIPT)-based multi-relay network with a direct link.To achieve high throughput in the network,a novel protocol is first developed,in which the network can switch between a direct transmission mode and a Single-Relay-Selection-based Cooperative Transmission(SRS-CT)mode that employs dynamic decode-and-forward relaying accomplished with Rateless Codes(RCs).Then,under this protocol,an optimization problem is formulated to jointly optimize the network operation mode and the resource allocation in the SRS-CT mode.The formulated problem is difficult to solve because not only does the noncausal Channel State Information(CSI)cause the problem to be stochastic,but also the energy state evolution at each relay is complicated by network operation mode decision and resource allocation.Assuming that noncausal CSI is available,the stochastic optimization issue is first to be addressed by solving an involved deterministic optimization problem via dynamic programming,where the complicated energy state evolution issue is addressed by a layered optimization method.Then,based on a finite-state Markov channel model and assuming that CSI statistical properties are known,the stochastic optimization problem is solved by extending the result derived for the noncausal CSI case to the causal CSI case.Finally,a myopic strategy is proposed to achieve a tradeoff between complexity and performance without the knowledge of CSI statistical properties.The simulation results verify that our proposed SRS-and-RC-based design can achieve a maximum of approximately 40%throughput gain over a simple SRS-and-RC-based baseline scheme in SWIPT-based multi-relay networks.展开更多
The plastic pollution has become one of the top environmental concerns.Substantial effort has been devoted into recycling waste plastic materials in a facile and economical way.In this work,we have successfully recycl...The plastic pollution has become one of the top environmental concerns.Substantial effort has been devoted into recycling waste plastic materials in a facile and economical way.In this work,we have successfully recycled a common type of plastic waste,i.e.,polystyrene(PS),into value-added functional materials through a cost-effective and facile dip-coating method.The resulted mixture of waste PS and SiO_(2),referred to as PS/SiO_(2),coated textile material is superhydrophobic and superoleophilic,showing an excellent resistance towards corrosive solutions(acid,alkaline,and saline),high temperature treatment,and mechanical abrasion.As a proof-of-concept application,the PS/SiO_(2)-coated textile is used to selectively separate oil/water mixtures through either absorption or filtration method.It also exhibits a surface self-cleaning property,which may be used as fabrics for dust-preventing cloths.Our work offers a new strategy to treat the waste for preparation of novel low-cost superhydrophobic materials for various applications.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 61872098 and Grant 61902084the Natural Science Foundation of Guangdong Province under Grant 2017A030313363.
文摘This paper studies a dual-hop Simultaneous Wireless Information and Power Transfer(SWIPT)-based multi-relay network with a direct link.To achieve high throughput in the network,a novel protocol is first developed,in which the network can switch between a direct transmission mode and a Single-Relay-Selection-based Cooperative Transmission(SRS-CT)mode that employs dynamic decode-and-forward relaying accomplished with Rateless Codes(RCs).Then,under this protocol,an optimization problem is formulated to jointly optimize the network operation mode and the resource allocation in the SRS-CT mode.The formulated problem is difficult to solve because not only does the noncausal Channel State Information(CSI)cause the problem to be stochastic,but also the energy state evolution at each relay is complicated by network operation mode decision and resource allocation.Assuming that noncausal CSI is available,the stochastic optimization issue is first to be addressed by solving an involved deterministic optimization problem via dynamic programming,where the complicated energy state evolution issue is addressed by a layered optimization method.Then,based on a finite-state Markov channel model and assuming that CSI statistical properties are known,the stochastic optimization problem is solved by extending the result derived for the noncausal CSI case to the causal CSI case.Finally,a myopic strategy is proposed to achieve a tradeoff between complexity and performance without the knowledge of CSI statistical properties.The simulation results verify that our proposed SRS-and-RC-based design can achieve a maximum of approximately 40%throughput gain over a simple SRS-and-RC-based baseline scheme in SWIPT-based multi-relay networks.
基金the support from Beijing Institute of Technology Research Fund Program for Young Scholars and the National Natural Science Foundation of China(No.22105021)H.Z.thanks the financial support from ITC via Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM)+1 种基金the start-up grant(No.9380100)grants(Nos.9610478,7020013,and 1886921)from City University of Hong Kong。
文摘The plastic pollution has become one of the top environmental concerns.Substantial effort has been devoted into recycling waste plastic materials in a facile and economical way.In this work,we have successfully recycled a common type of plastic waste,i.e.,polystyrene(PS),into value-added functional materials through a cost-effective and facile dip-coating method.The resulted mixture of waste PS and SiO_(2),referred to as PS/SiO_(2),coated textile material is superhydrophobic and superoleophilic,showing an excellent resistance towards corrosive solutions(acid,alkaline,and saline),high temperature treatment,and mechanical abrasion.As a proof-of-concept application,the PS/SiO_(2)-coated textile is used to selectively separate oil/water mixtures through either absorption or filtration method.It also exhibits a surface self-cleaning property,which may be used as fabrics for dust-preventing cloths.Our work offers a new strategy to treat the waste for preparation of novel low-cost superhydrophobic materials for various applications.
