Peer-to-peer(P2P)energy trading refers to a type of decentralized transaction,where the energy from distributed energy resources is directly traded between peers.A key challenge in peer-to-peer energy trading is desig...Peer-to-peer(P2P)energy trading refers to a type of decentralized transaction,where the energy from distributed energy resources is directly traded between peers.A key challenge in peer-to-peer energy trading is designing a safe,efficient,and transparent trading model and operating mechanism.In this study,we consider a P2P trading environment based on blockchain technology,where prosumers can submit bids or offers without knowing the reports of others.We propose an Arrow-d’Aspremont-Gerard-Varet(AGV)-based mechanism to encourage prosumers to submit their real reserve price and determine the P2P transaction price.We demonstrate that the AGV mechanism can achieve Bayesian incentive compatibility and budget balance.Kernel density estimation(KDE)is used to derive the prior distribution from the historical bid/offer information of the agents.Case studies are carried out to analyze and evaluate the proposed mechanism.Simulation results verify the effectiveness of the proposed mechanism in guiding agents to report the true reserve price while maximizing social welfare.Moreover,we discuss the advantages of budget balance for decentralized trading by comparing the Vickrey-Clarke-Groves(VCG)and AGV mechanisms.展开更多
The rapid growth of distributed renewable energy penetration is promoting the evolution of the energy system toward decentralization and decentralized and digitized smart grids.This study was based on energy blockchai...The rapid growth of distributed renewable energy penetration is promoting the evolution of the energy system toward decentralization and decentralized and digitized smart grids.This study was based on energy blockchain,and developed a dual-biding mechanism based on the real-time energy surplus and demand in the local smart grid,which is expected to enable reliable,affordable,and clean energy supply in smart communities.In the proposed system,economic benefits could be achieved by replacing fossil-fuel-based electricity with the high penetration of affordable solar PV electricity.The reduction of energy surplus realized by distributed energy production and P2P energy trading,within the smart grid results in less transmission loss and lower requirements for costly upgrading of existing grids.By adopting energy blockchain and smart contract technologies,energy secure trading with a low risk of privacy leakage could be accommodated.The prototype is examined through a case study,and the feasibility and efficiency of the proposed mechanism are further validated by scenario analysis.展开更多
may incur significant bandwidth for executing more com- plicated search queries such as multiple-attribute queries. In order to reduce query overhead, KSS (keyword-set search) by Gnawali partitions the index by a set ...may incur significant bandwidth for executing more com- plicated search queries such as multiple-attribute queries. In order to reduce query overhead, KSS (keyword-set search) by Gnawali partitions the index by a set of keywords. However, a KSS index is considerably larger than a standard inverted index, since there are more word sets than there are individual words. And the insert overhead and storage overhead are obviously un- acceptable for full-text search on a collection of documents even if KSS uses the distance window technology. In this paper, we extract the relationship information between query keywords from websites’ queries logs to improve performance of KSS system. Experiments results clearly demonstrated that the improved keyword-set search system based on keywords relationship (KRBKSS) is more efficient than KSS index in insert overhead and storage overhead, and a standard inverted index in terms of communication costs for query.展开更多
IIn order to improve the performance of wireless distributed peer-to-peer(P2P)files sharing systems,a general system architecture and a novel peer selecting model based on fuzzy cognitive maps(FCM)are proposed in this...IIn order to improve the performance of wireless distributed peer-to-peer(P2P)files sharing systems,a general system architecture and a novel peer selecting model based on fuzzy cognitive maps(FCM)are proposed in this paper.The new model provides an effective approach on choosing an optimal peer from several resource discovering results for the best file transfer.Compared with the traditional min-hops scheme that uses hops as the only selecting criterion,the proposed model uses FCM to investigate the complex relationships among various relative factors in wireless environments and gives an overall evaluation score on the candidate.It also has strong scalability for being independent of specified P2P resource discovering protocols.Furthermore,a complete implementation is explained in concrete modules.The simulation results show that the proposed model is effective and feasible compared with min-hops scheme,with the success transfer rate increased by at least 20% and transfer time improved as high as 34%.展开更多
The recent and unprecedented surge of public interest in peer-to-peer (P2P) file-sharing systems has led to a variety of interesting research questions. How to minimize threats in such an open community is an impor-ta...The recent and unprecedented surge of public interest in peer-to-peer (P2P) file-sharing systems has led to a variety of interesting research questions. How to minimize threats in such an open community is an impor-tant research topic. Trust models have been widely used in estimating the trustworthiness of peers in P2P file-sharing systems where peers can transact with each other without prior experience. However, current P2P trust models almost take no consideration for the nature of trust, fuzzy, complex and dynamic, which results in low efficiency in resisting the attacks of malicious nodes. In this paper, a new trust model named NatureTrust that can alleviate the shortage brought by the nature of trust is proposed. In order to cope with the fuzzy characteristic of trust, linguistic terms are used to express trust. Additionally, fuzzy inference rules are employed to evaluate trust of each transaction so as to handle the complex characteristic of trust. Fur-thermore, risk factor is deployed into NatureTrust to represent and reason with the dynamic characteristic of trust. Both risk and trust factors are considered in evaluating the trustworthiness of each peer. Experimental results show that the trust model analyzed here thus stands against malicious act effectively.展开更多
The polymerization of methyl methacrylate (MMA) initiated by organic peroxide and polymerizable aromatic tertiary amine such as N, N-di (2-α-methylacryloyloxy propyl)-p-toluidine (MP)_2PT binary system has been studi...The polymerization of methyl methacrylate (MMA) initiated by organic peroxide and polymerizable aromatic tertiary amine such as N, N-di (2-α-methylacryloyloxy propyl)-p-toluidine (MP)_2PT binary system has been studied. It was found that the (MP)_2PT promotes MMA polymerization, and the kinetics of MMA polymerization fits the radical polymerization rate equation. Based on the ESR studies and the end-group analysis the initiation mechanism is proposed.展开更多
Peer-to-Peer （P2P） botnet has emerged as one of the most serious threats to lnternet security. To effectively elimi- nate P2P botnet, a delayed SEIR model is proposed,which can portray the formation process of P2P b...Peer-to-Peer （P2P） botnet has emerged as one of the most serious threats to lnternet security. To effectively elimi- nate P2P botnet, a delayed SEIR model is proposed,which can portray the formation process of P2P botnet. Then, the local stability at equilibria is carefully analyzed by considering the eigenvalues＇ distributed ranges of characteristic equations. Both mathematical analysis and numerical simulations show that the dynamical features of the proposed model rely on the basic re- production number and time delay r. The results can help us to better understand the propagation behaviors of P2P botnet and design effective counter-botnet methods.展开更多
One of the key challenges in ad-hoc networks is the resource discovery problem.How efciently&quickly the queried resource/object can be resolved in such a highly dynamic self-evolving network is the underlying que...One of the key challenges in ad-hoc networks is the resource discovery problem.How efciently&quickly the queried resource/object can be resolved in such a highly dynamic self-evolving network is the underlying question?Broadcasting is a basic technique in the Mobile Ad-hoc Networks(MANETs),and it refers to sending a packet from one node to every other node within the transmission range.Flooding is a type of broadcast where the received packet is retransmitted once by every node.The naive ooding technique oods the network with query messages,while the random walk scheme operates by contacting subsets of each node’s neighbors at every step,thereby restricting the search space.Many earlier works have mainly focused on the simulation-based analysis of ooding technique,and its variants,in a wired network scenario.Although,there have been some empirical studies in peer-to-peer(P2P)networks,the analytical results are still lacking,especially in the context of mobile P2P networks.In this article,we mathematically model different widely used existing search techniques,and compare with the proposed improved random walk method,a simple lightweight approach suitable for the non-DHT architecture.We provide analytical expressions to measure the performance of the different ooding-based search techniques,and our proposed technique.We analytically derive 3 relevant key performance measures,i.e.,the avg.number of steps needed to nd a resource,the probability of locating a resource,and the avg.number of messages generated during the entire search process.展开更多
Applying ontology to describe resource metadata richly in the peer-to-peer environment has become current research trend. In this semantic peer-to-peer environment, indexing semantic element of resource description to...Applying ontology to describe resource metadata richly in the peer-to-peer environment has become current research trend. In this semantic peer-to-peer environment, indexing semantic element of resource description to support efficient resource location is a difficult and challenging problem. This paper provided a hybrid indexing architecture, which combines local indexing and global indexing. It uses community strategy and semantic routing strategy to organize key layer metadata element and uses DHT (distributed hash table) to index extensional layer metadata element. Compared with related system, this approach is more efficient in resource location and more scalable.展开更多
More and more modern group oriented collaborativeapplications use the peer-to-peer(P2P)paradigm tobe independent of expensive infrastructures as theyare,for instance,provided for audio and video conferencesby H.323 sy...More and more modern group oriented collaborativeapplications use the peer-to-peer(P2P)paradigm tobe independent of expensive infrastructures as theyare,for instance,provided for audio and video conferencesby H.323 systems.Decentralized collaborativeP2P solutions require appropriate mechanismsto protect group privacy and data integrity.A centralizedclient/server based video conference system canbe well shielded in a standard manner,whilst thereare no off-the-shelf approaches to secure a P2P videoconference up to now.The paper addresses this issueand presents a flexible security architecture.Usingthe BRAVIS system[4]as an example it shows howthe architecture can be embedded into a P2P videoconferencing system.展开更多
Peer-to-peer (P2P) technology provides a cost-effective and scalable way to distribute video data. However, high heterogeneity of the P2P network, which rises not only from heterogeneous link capacity between peers bu...Peer-to-peer (P2P) technology provides a cost-effective and scalable way to distribute video data. However, high heterogeneity of the P2P network, which rises not only from heterogeneous link capacity between peers but also from dynamic variation of available bandwidth, brings forward great challenge to video streaming. To attack this problem, an adaptive scheme based on rate-distortion optimization (RDO) is proposed in this paper. While low complexity RDO based frame dropping is exploited to shape bitrate into available bandwidth in peers, the streamed bitstream is dynamically switched among multiple available versions in an RDO way by the streaming server. Simulation results show that the proposed scheme based on RDO achieves great gain in overall perceived quality over simple heuristic schemes.展开更多
To enable accessing web information at semantic level, this paper develops a semantic query rewriting mechanism on peer to peer XISs with complex ontology mapping technology. It discusses the patterns of complex ontol...To enable accessing web information at semantic level, this paper develops a semantic query rewriting mechanism on peer to peer XISs with complex ontology mapping technology. It discusses the patterns of complex ontology mappings at first, and the ontology-based query mechanism in peer to peer environment. The extension of XML query algebra and XML query rewriting mechanism are dissussed in detail.展开更多
In control system, tag table is like a dictionary mapping tagname to address. Therefore, applications on workstation may use tagname to access different data in system. Normally tag table generated by configuration so...In control system, tag table is like a dictionary mapping tagname to address. Therefore, applications on workstation may use tagname to access different data in system. Normally tag table generated by configuration software will transfer to other workstation in system manually after system configuration, which is inconvenient and failible. The development of peer-to-peer （P2P） network technology and the realization of control system based on P2P network make the auto distn＇bution of tag table possible. In this paper based on file sharing technology the presented method realizes the auto distn＇bution of tag table.展开更多
Free riding has a great influence on the expandability,robustness and availability of Peer-to-Peer(P2P) network.Controlling free riding has become a hot research issue both in academic and industrial communities.An in...Free riding has a great influence on the expandability,robustness and availability of Peer-to-Peer(P2P) network.Controlling free riding has become a hot research issue both in academic and industrial communities.An incentive scheme is proposed to overcoming free riding in P2P network in this paper.According to the behavior and function of nodes,the P2P network is abstracted to be a Distributed and Monitoring-based Hierarchical Structure Mechanism(DMHSM) model.A utility function based on several influencing factors is defined to determine the contribution of peers to the whole system.This paper also introduces reputation and permit mechanism into the scheme to guarantee the Quality of Service(QoS) and to reward or punish peers in the network.Finally,the simulation results verify the effectiveness and feasibility of this model.展开更多
In order to solve the problem that the existing data scheduling algorithm cannot make full use of neighbors' bandwidth resources when allocating data request among several senders in the multisender based P2P stre...In order to solve the problem that the existing data scheduling algorithm cannot make full use of neighbors' bandwidth resources when allocating data request among several senders in the multisender based P2P streaming system,a peer priority based scheduling algorithm is proposed.The algorithm calculates neighbors' priority based on peers' historical service evaluation as well as how many wanted data that the neighbor has.The data request allocated to each neighbor is adjusted dynamically according to the priority when scheduling.Peers with high priority are preferred to allocate more data request.Experiment shows the algorithm can make full use of neighbors' bandwidth resources to transmit data to reduce server pressure effectively and improve system scalability.展开更多
Most overlay of existing P2P streaming systems just focus on the view point of video content data.An multi-dimensional overlay for the P2P streaming system(MDOPS) is proposed for providing multi-dimensional view inclu...Most overlay of existing P2P streaming systems just focus on the view point of video content data.An multi-dimensional overlay for the P2P streaming system(MDOPS) is proposed for providing multi-dimensional view including video data,peers' service capability and online stability based on locality sensitive hashing.MDOPS organizes all Live/VoD peers and the above multi-dimensional information in a one-dimensinal DHT,uses range resource information publish/search and introduces multiple load balancing methods.MDOPS maintains an additional candidate coordinating peer list with high qualified peers who own the video data the peer would possibly access currently and in future.This list could speed up the process of searching peers for data scheduling layer.Simulation experiment based on trace of real streaming system has testified that MDOPS can effectively improve the quality of search results and smooth load distribution among peers without increasing the cost of resource publish/search.展开更多
Battery energy storage systems(BESSs)serve a crucial role in balancing energy fluctuations and reducing carbon emissions in net-zero power systems.However,the efficiency and cost performance have remained significant ...Battery energy storage systems(BESSs)serve a crucial role in balancing energy fluctuations and reducing carbon emissions in net-zero power systems.However,the efficiency and cost performance have remained significant challenges,which hinders the widespread adoption and development of BESSs.To address these challenges,this paper proposes a real-time energy management scheme that considers the involvement of prosumers to support net-zero power systems.The scheme is based on two shared energy storage models,referred to as energy storage sale model and power line lease model.The energy storage sale model balances real-time power deviations by energy interaction with the goal of minimizing system costs while generating revenue for shared energy storage providers(ESPs).Additionally,power line lease model supports peer-to-peer(P2P)power trading among prosumers through the power lines laid by ESPs to connect each prosumer.This model allows ESP to earn profits from the use of power lines while balancing power deviations and better consuming renewable energy.Experimental results validate the effectiveness of the proposed scheme,ensuring stable power supply for net-zero power systems and providing benefits for both the ESP and prosumers.展开更多
基金supported by National Natural Science Foundation of China(U2066211,52177124,52107134)the Institute of Electrical Engineering,CAS(E155610101)+1 种基金the DNL Cooperation Fund,CAS(DNL202023)the Youth Innovation Promotion Association of CAS(2019143).
文摘Peer-to-peer(P2P)energy trading refers to a type of decentralized transaction,where the energy from distributed energy resources is directly traded between peers.A key challenge in peer-to-peer energy trading is designing a safe,efficient,and transparent trading model and operating mechanism.In this study,we consider a P2P trading environment based on blockchain technology,where prosumers can submit bids or offers without knowing the reports of others.We propose an Arrow-d’Aspremont-Gerard-Varet(AGV)-based mechanism to encourage prosumers to submit their real reserve price and determine the P2P transaction price.We demonstrate that the AGV mechanism can achieve Bayesian incentive compatibility and budget balance.Kernel density estimation(KDE)is used to derive the prior distribution from the historical bid/offer information of the agents.Case studies are carried out to analyze and evaluate the proposed mechanism.Simulation results verify the effectiveness of the proposed mechanism in guiding agents to report the true reserve price while maximizing social welfare.Moreover,we discuss the advantages of budget balance for decentralized trading by comparing the Vickrey-Clarke-Groves(VCG)and AGV mechanisms.
基金Fundings that permitted this research were granted by Australia CRC for Low Carbon Living through the Project“Integrated Carbon Metrics(ICM)”(RP2007)the National Natural Science Foundation of China(51908064)the Natural Science Foundation of Hunan Province(2021JJ30717).
文摘The rapid growth of distributed renewable energy penetration is promoting the evolution of the energy system toward decentralization and decentralized and digitized smart grids.This study was based on energy blockchain,and developed a dual-biding mechanism based on the real-time energy surplus and demand in the local smart grid,which is expected to enable reliable,affordable,and clean energy supply in smart communities.In the proposed system,economic benefits could be achieved by replacing fossil-fuel-based electricity with the high penetration of affordable solar PV electricity.The reduction of energy surplus realized by distributed energy production and P2P energy trading,within the smart grid results in less transmission loss and lower requirements for costly upgrading of existing grids.By adopting energy blockchain and smart contract technologies,energy secure trading with a low risk of privacy leakage could be accommodated.The prototype is examined through a case study,and the feasibility and efficiency of the proposed mechanism are further validated by scenario analysis.
基金Project supported by the National Natural Science Foundation of China (No. 60221120145) and Science & Technology Committee of Shanghai Municipality Key Project (No. 02DJ14045), China
文摘may incur significant bandwidth for executing more com- plicated search queries such as multiple-attribute queries. In order to reduce query overhead, KSS (keyword-set search) by Gnawali partitions the index by a set of keywords. However, a KSS index is considerably larger than a standard inverted index, since there are more word sets than there are individual words. And the insert overhead and storage overhead are obviously un- acceptable for full-text search on a collection of documents even if KSS uses the distance window technology. In this paper, we extract the relationship information between query keywords from websites’ queries logs to improve performance of KSS system. Experiments results clearly demonstrated that the improved keyword-set search system based on keywords relationship (KRBKSS) is more efficient than KSS index in insert overhead and storage overhead, and a standard inverted index in terms of communication costs for query.
基金Sponsored by the National Natural Science Foundation of China(Grant No.60672124 and 60832009)Hi-Tech Research and Development Program(National 863 Program)(Grant No.2007AA01Z221)
文摘IIn order to improve the performance of wireless distributed peer-to-peer(P2P)files sharing systems,a general system architecture and a novel peer selecting model based on fuzzy cognitive maps(FCM)are proposed in this paper.The new model provides an effective approach on choosing an optimal peer from several resource discovering results for the best file transfer.Compared with the traditional min-hops scheme that uses hops as the only selecting criterion,the proposed model uses FCM to investigate the complex relationships among various relative factors in wireless environments and gives an overall evaluation score on the candidate.It also has strong scalability for being independent of specified P2P resource discovering protocols.Furthermore,a complete implementation is explained in concrete modules.The simulation results show that the proposed model is effective and feasible compared with min-hops scheme,with the success transfer rate increased by at least 20% and transfer time improved as high as 34%.
文摘The recent and unprecedented surge of public interest in peer-to-peer (P2P) file-sharing systems has led to a variety of interesting research questions. How to minimize threats in such an open community is an impor-tant research topic. Trust models have been widely used in estimating the trustworthiness of peers in P2P file-sharing systems where peers can transact with each other without prior experience. However, current P2P trust models almost take no consideration for the nature of trust, fuzzy, complex and dynamic, which results in low efficiency in resisting the attacks of malicious nodes. In this paper, a new trust model named NatureTrust that can alleviate the shortage brought by the nature of trust is proposed. In order to cope with the fuzzy characteristic of trust, linguistic terms are used to express trust. Additionally, fuzzy inference rules are employed to evaluate trust of each transaction so as to handle the complex characteristic of trust. Fur-thermore, risk factor is deployed into NatureTrust to represent and reason with the dynamic characteristic of trust. Both risk and trust factors are considered in evaluating the trustworthiness of each peer. Experimental results show that the trust model analyzed here thus stands against malicious act effectively.
文摘The polymerization of methyl methacrylate (MMA) initiated by organic peroxide and polymerizable aromatic tertiary amine such as N, N-di (2-α-methylacryloyloxy propyl)-p-toluidine (MP)_2PT binary system has been studied. It was found that the (MP)_2PT promotes MMA polymerization, and the kinetics of MMA polymerization fits the radical polymerization rate equation. Based on the ESR studies and the end-group analysis the initiation mechanism is proposed.
基金National Natural Science Foundation of China(No.61379125)Program for Basic Research of Shanxi Province(No.2012011015-3)Higher School of Science and Technology Innovation Project of Shanxi Province(No.2013148)
文摘Peer-to-Peer （P2P） botnet has emerged as one of the most serious threats to lnternet security. To effectively elimi- nate P2P botnet, a delayed SEIR model is proposed,which can portray the formation process of P2P botnet. Then, the local stability at equilibria is carefully analyzed by considering the eigenvalues＇ distributed ranges of characteristic equations. Both mathematical analysis and numerical simulations show that the dynamical features of the proposed model rely on the basic re- production number and time delay r. The results can help us to better understand the propagation behaviors of P2P botnet and design effective counter-botnet methods.
文摘One of the key challenges in ad-hoc networks is the resource discovery problem.How efciently&quickly the queried resource/object can be resolved in such a highly dynamic self-evolving network is the underlying question?Broadcasting is a basic technique in the Mobile Ad-hoc Networks(MANETs),and it refers to sending a packet from one node to every other node within the transmission range.Flooding is a type of broadcast where the received packet is retransmitted once by every node.The naive ooding technique oods the network with query messages,while the random walk scheme operates by contacting subsets of each node’s neighbors at every step,thereby restricting the search space.Many earlier works have mainly focused on the simulation-based analysis of ooding technique,and its variants,in a wired network scenario.Although,there have been some empirical studies in peer-to-peer(P2P)networks,the analytical results are still lacking,especially in the context of mobile P2P networks.In this article,we mathematically model different widely used existing search techniques,and compare with the proposed improved random walk method,a simple lightweight approach suitable for the non-DHT architecture.We provide analytical expressions to measure the performance of the different ooding-based search techniques,and our proposed technique.We analytically derive 3 relevant key performance measures,i.e.,the avg.number of steps needed to nd a resource,the probability of locating a resource,and the avg.number of messages generated during the entire search process.
文摘Applying ontology to describe resource metadata richly in the peer-to-peer environment has become current research trend. In this semantic peer-to-peer environment, indexing semantic element of resource description to support efficient resource location is a difficult and challenging problem. This paper provided a hybrid indexing architecture, which combines local indexing and global indexing. It uses community strategy and semantic routing strategy to organize key layer metadata element and uses DHT (distributed hash table) to index extensional layer metadata element. Compared with related system, this approach is more efficient in resource location and more scalable.
文摘More and more modern group oriented collaborativeapplications use the peer-to-peer(P2P)paradigm tobe independent of expensive infrastructures as theyare,for instance,provided for audio and video conferencesby H.323 systems.Decentralized collaborativeP2P solutions require appropriate mechanismsto protect group privacy and data integrity.A centralizedclient/server based video conference system canbe well shielded in a standard manner,whilst thereare no off-the-shelf approaches to secure a P2P videoconference up to now.The paper addresses this issueand presents a flexible security architecture.Usingthe BRAVIS system[4]as an example it shows howthe architecture can be embedded into a P2P videoconferencing system.
文摘Peer-to-peer (P2P) technology provides a cost-effective and scalable way to distribute video data. However, high heterogeneity of the P2P network, which rises not only from heterogeneous link capacity between peers but also from dynamic variation of available bandwidth, brings forward great challenge to video streaming. To attack this problem, an adaptive scheme based on rate-distortion optimization (RDO) is proposed in this paper. While low complexity RDO based frame dropping is exploited to shape bitrate into available bandwidth in peers, the streamed bitstream is dynamically switched among multiple available versions in an RDO way by the streaming server. Simulation results show that the proposed scheme based on RDO achieves great gain in overall perceived quality over simple heuristic schemes.
基金Supported by the Natural Science Foundation ofHubei Province(2005ABA235) Key Project of Science Research ofEducation Agency of Hubei Province (Z200511005)
文摘To enable accessing web information at semantic level, this paper develops a semantic query rewriting mechanism on peer to peer XISs with complex ontology mapping technology. It discusses the patterns of complex ontology mappings at first, and the ontology-based query mechanism in peer to peer environment. The extension of XML query algebra and XML query rewriting mechanism are dissussed in detail.
基金National Natural Science Foundations of China ( No.60774059, No.60834002)the Excellent Discipline Head Plan Project of Shanghai, China (No.08XD14018)
文摘In control system, tag table is like a dictionary mapping tagname to address. Therefore, applications on workstation may use tagname to access different data in system. Normally tag table generated by configuration software will transfer to other workstation in system manually after system configuration, which is inconvenient and failible. The development of peer-to-peer （P2P） network technology and the realization of control system based on P2P network make the auto distn＇bution of tag table possible. In this paper based on file sharing technology the presented method realizes the auto distn＇bution of tag table.
基金Supported by the National Natural Science Foundation of China (No.60873203)the Natural Science Foundation of Hebei Province (No.F2008000646)the Guidance Program of the Department of Science and Technology in Hebei Province (No.072135192)
文摘Free riding has a great influence on the expandability,robustness and availability of Peer-to-Peer(P2P) network.Controlling free riding has become a hot research issue both in academic and industrial communities.An incentive scheme is proposed to overcoming free riding in P2P network in this paper.According to the behavior and function of nodes,the P2P network is abstracted to be a Distributed and Monitoring-based Hierarchical Structure Mechanism(DMHSM) model.A utility function based on several influencing factors is defined to determine the contribution of peers to the whole system.This paper also introduces reputation and permit mechanism into the scheme to guarantee the Quality of Service(QoS) and to reward or punish peers in the network.Finally,the simulation results verify the effectiveness and feasibility of this model.
基金Supported by the National High Technology Research and Development Program of China(No.2009AA01A339,2008AA01A317)the National Natural Science Foundation of China for Distinguished Young Scholars(No.60903218F0208)the Science and Technology Support Plan of China(No.2008BAH28B04)
文摘In order to solve the problem that the existing data scheduling algorithm cannot make full use of neighbors' bandwidth resources when allocating data request among several senders in the multisender based P2P streaming system,a peer priority based scheduling algorithm is proposed.The algorithm calculates neighbors' priority based on peers' historical service evaluation as well as how many wanted data that the neighbor has.The data request allocated to each neighbor is adjusted dynamically according to the priority when scheduling.Peers with high priority are preferred to allocate more data request.Experiment shows the algorithm can make full use of neighbors' bandwidth resources to transmit data to reduce server pressure effectively and improve system scalability.
基金Supported by the National High Technology Research and Development Programme of China(No.2008AA01A317)the National Natural Science Foundation of China(No.60903218)
文摘Most overlay of existing P2P streaming systems just focus on the view point of video content data.An multi-dimensional overlay for the P2P streaming system(MDOPS) is proposed for providing multi-dimensional view including video data,peers' service capability and online stability based on locality sensitive hashing.MDOPS organizes all Live/VoD peers and the above multi-dimensional information in a one-dimensinal DHT,uses range resource information publish/search and introduces multiple load balancing methods.MDOPS maintains an additional candidate coordinating peer list with high qualified peers who own the video data the peer would possibly access currently and in future.This list could speed up the process of searching peers for data scheduling layer.Simulation experiment based on trace of real streaming system has testified that MDOPS can effectively improve the quality of search results and smooth load distribution among peers without increasing the cost of resource publish/search.
基金supported in part by the National Key Research and Development Program of China(No.2018YFA0702200)the National Natural Science Foundation of China(No.52377079)the Liaoning Revitalization Talents Program(No.XLYC2007181)。
文摘Battery energy storage systems(BESSs)serve a crucial role in balancing energy fluctuations and reducing carbon emissions in net-zero power systems.However,the efficiency and cost performance have remained significant challenges,which hinders the widespread adoption and development of BESSs.To address these challenges,this paper proposes a real-time energy management scheme that considers the involvement of prosumers to support net-zero power systems.The scheme is based on two shared energy storage models,referred to as energy storage sale model and power line lease model.The energy storage sale model balances real-time power deviations by energy interaction with the goal of minimizing system costs while generating revenue for shared energy storage providers(ESPs).Additionally,power line lease model supports peer-to-peer(P2P)power trading among prosumers through the power lines laid by ESPs to connect each prosumer.This model allows ESP to earn profits from the use of power lines while balancing power deviations and better consuming renewable energy.Experimental results validate the effectiveness of the proposed scheme,ensuring stable power supply for net-zero power systems and providing benefits for both the ESP and prosumers.
