Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massi...Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massive decentralized applications(d Apps) in Io T usecases, Edgence(EDGe + intellig ENCE) is proposed to use edge clouds to access Io T devices and users, and then use its in-built blockchain to realize self-governing and self-supervision of the edge clouds. Edgence proposes to use masternode technology to introduce Io T devices and users into a closed blockchain system, which can extend the range of blockchain to Io T-based d Apps. Further, masternodes do good to scalability by raising the TPS(transactions per second) of the blockchain network. To support various d Apps, a three-tier validation is proposed, namely script validation, smartcontract validation, and masternode validation. To avoid energy consumption resulted by blockchain consensus, Edgence proposes a random but verifiable way to elect a masternode to generate each new block. The potential of the tailored Edgence is shown by examples of decentralized crowdsourcing and AI training.展开更多
With the development of blockchain technology,a variety of mutually independent blockchains such as Bitcoin and Ethereum,as well as private and consortium chains,coexist in large numbers.As a linker of the blockchain ...With the development of blockchain technology,a variety of mutually independent blockchains such as Bitcoin and Ethereum,as well as private and consortium chains,coexist in large numbers.As a linker of the blockchain network,blockchain interoperability will link more blockchain ecosystems,realize the interconnection of the blockchain and enhance the scalability of the blockchain.This paper summarizes typical blockchain interoperability projects.Firstly,it proposes a blockchain interoperability definition and an architecture model.Secondly,it analyzes technical characteristics of blockchain interoperability,and typical blockchain interoperability cases are compared.Finally,the trend of future development of blockchain interoperability technology is summarized and discussed.展开更多
Tim Berners-Lee developed the internet at CERN in early 1990 with fundamental technologies such as HTML,URL,and HTTP which became the foundation of the web.The contemporary web we use today has been much advanced over...Tim Berners-Lee developed the internet at CERN in early 1990 with fundamental technologies such as HTML,URL,and HTTP which became the foundation of the web.The contemporary web we use today has been much advanced over a period of time ever since the innovation of the World Wide Web was introduced.The static web was the first version of the web,which was the read-only web.Succeeding development in web technology is web 3.0 which is a distributed and decentralized web with emerging technologies.This article emphasizes the comparison of important details with the evolution of the web.The paper also demonstrates the transactional architecture of DApps in networks and decentralized state machines.Decentralization,connectivity,the semantic web,augmented reality and artificial intelligence are the signifi-cant features of web 3.0 technology.These features are tremendously used in decision-making on critical issues,which are discussed elaborately in the arti-cle.The paper provides various technologies to implement web 3.0 efficiently.The evolution of web 3.0 brings forth opportunities and challenges.The opportunities are the ownership of the data and a personalized web browsing experience.The main concerns are security and scalability requirements for blockchain transactions.The article also laid out the challenges that can be considered for further research.展开更多
Smart contract has been the core of blockchain systems and other blockchain-based systems since Blockchain 2.0.Various operations on blockchain are performed through the invocation and execution of smart contracts.Thi...Smart contract has been the core of blockchain systems and other blockchain-based systems since Blockchain 2.0.Various operations on blockchain are performed through the invocation and execution of smart contracts.This leads to extensive combinations between blockchain,smart contract,Internet of Things(IoT)and Cyber-Physical System(CPS)applications,and then many blockchain-based IoT or CPS applications emerge to provide multiple benefits to the economy and society.In this case,obtaining a better understanding of smart contracts will contribute to the easier operation,higher efficiency and stronger security of those blockchain-based systems and applications.Many existing studies on smart contract analysis are based on similarity calculation and smart contract classification.However,smart contract is a piece of code with special characteristics and most of smart contracts are stored without any category labels,which leads to difficulties of smart contract classification.As the back end of a blockchain-based Decentralized Application(DApp)is one or several smart contracts,DApps with labeled categories and open source codes are applied to achieve a supervised smart contract classification.A three-phase approach is proposed to categorize DApps based on various data features.In this approach,5,659 DApps with smart contract source codes and pre-tagged categories are first obtained based on massive collected DApps and smart contracts from Ethereum,State of the DApps and DappRadar.Then feature extraction and construction methods are designed to form multi-feature vectors that could present the major characteristics of DApps.Finally,a fused classification model consisting of KNN,XGBoost and random forests is applied to the multi-feature vectors of all DApps for performing DApp classification.The experimental results show that the method is effective.In addition,some positive correlations between feature variables and categories,as well as several user behavior patterns of DApp calls,are found in this paper.展开更多
The title compound [2-dapp]2[Zn(dmit)2] synthesized by the direct reaction of [Et4N]2[Zn(dmit)2] and [2-dapp]I crystallizes in monoclinic, space group P2l/c with a = 29.7436(6), b = l0.6266(3), c = l3.6161(4) ? b = 93...The title compound [2-dapp]2[Zn(dmit)2] synthesized by the direct reaction of [Et4N]2[Zn(dmit)2] and [2-dapp]I crystallizes in monoclinic, space group P2l/c with a = 29.7436(6), b = l0.6266(3), c = l3.6161(4) ? b = 93.l16(l)? V = 4297.3 ?, Z = 4, Dc = 1.448 g/cm3, m = 1.091 mm-1 and F(000) = 1936. The structure was refined by fu1l-matrix 1east-squares methods to the final R = 0.075 and wR = 0.l16, revealing the zinc-bis (dmit) anions interact strongly with the planar cation, 2-dapp+, by the hydrogen bond C(l)H(lC)…S(7) (x, 3/2y, 1/2+z).展开更多
N-cetylpyridinium iodide (N-CPI) as a new electric additive for enhancing photovoltaic performance of the dye-sensitized solar cell (DSSC) was studied.It showed high efficiency for enhancing both the open-circuit volt...N-cetylpyridinium iodide (N-CPI) as a new electric additive for enhancing photovoltaic performance of the dye-sensitized solar cell (DSSC) was studied.It showed high efficiency for enhancing both the open-circuit voltage and the short-circuit current density of DSSC when the suitable amount of N-CPI as 0.02 M was added in liquid electrolyte.The energy conversion effi- ciency of DSSC increased from 4.429% to 6.535%,with 47.55% enhancement.Therefore,it is a highly efficient electric addi- tive for DSSC.The intrinsic reason is owing to the special molecular structure of N-CPI,which contains two different polarity groups.As a surfactant,N-CPI could form ordered arrangement in liquid electrolyte,which affects the diffusing ability and the redox reaction of I-/I3-,and further affects the photovoltaic performance of DSSC.展开更多
Blockchain software development is becoming more and more important for any modern software developer and IT startup.Nonetheless,blockchain software production still lacks a disciplined,organized and mature developmen...Blockchain software development is becoming more and more important for any modern software developer and IT startup.Nonetheless,blockchain software production still lacks a disciplined,organized and mature development process,as demonstrated by the many and(in)famous failures and frauds occurred in recent years.In this paper we present ABCDE,a complete method addressing blockchain software development.The method considers the software integration among the blockchain components—smart contracts,libraries,data structures—and the out-of-chain components,such as web or mobile applications,which all together constitute a complete DApp system.We advocate for ABCDE the use of agile practices,because these are suited to develop systems whose requirements are not completely understood since the beginning,or tend to change,as it is the case of most blockchain-based applications.ABCDE is based on Scrum,and is therefore iterative and incremental.From Scrum,we kept the requirement gathering with user stories,the iterative-incremental approach,the key roles,and the meetings.The main difference with Scrum is the separation of development activities in two flows—one for smart contracts and the other for out-of-chain software interacting with the blockchain—each performed iteratively,with integration activities every 2–3 iterations.ABCDE makes explicit the activities that must be performed to design,develop,test and integrate smart contracts and out-of-chain software,and documents the smart contracts using formal diagrams to help development,security assessment,and maintenance.A diagram derived from UML class diagram helps to effectively model the data structure of smart contracts,whereas the exchange of messages between the entities of the system is modeled using a modified UML sequence diagram.The proposed method has also specific activities for security assessment and gas optimization,through systematic use of patterns and checklists.ABCDE focuses on Ethereum blockchain and its Solidity language,but preserves generality and with proper modifications might be applied to any blockchain software project.ABCDE method is described in detail,and an example is given to show how to concretely implement the various development steps.展开更多
基金supported in part by the National Science Foundation of China(Grant No.61922017).
文摘Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massive decentralized applications(d Apps) in Io T usecases, Edgence(EDGe + intellig ENCE) is proposed to use edge clouds to access Io T devices and users, and then use its in-built blockchain to realize self-governing and self-supervision of the edge clouds. Edgence proposes to use masternode technology to introduce Io T devices and users into a closed blockchain system, which can extend the range of blockchain to Io T-based d Apps. Further, masternodes do good to scalability by raising the TPS(transactions per second) of the blockchain network. To support various d Apps, a three-tier validation is proposed, namely script validation, smartcontract validation, and masternode validation. To avoid energy consumption resulted by blockchain consensus, Edgence proposes a random but verifiable way to elect a masternode to generate each new block. The potential of the tailored Edgence is shown by examples of decentralized crowdsourcing and AI training.
基金supported in part by the 2020 Industrial Internet Innovation and Development Project:Network Identifier Construction Project。
文摘With the development of blockchain technology,a variety of mutually independent blockchains such as Bitcoin and Ethereum,as well as private and consortium chains,coexist in large numbers.As a linker of the blockchain network,blockchain interoperability will link more blockchain ecosystems,realize the interconnection of the blockchain and enhance the scalability of the blockchain.This paper summarizes typical blockchain interoperability projects.Firstly,it proposes a blockchain interoperability definition and an architecture model.Secondly,it analyzes technical characteristics of blockchain interoperability,and typical blockchain interoperability cases are compared.Finally,the trend of future development of blockchain interoperability technology is summarized and discussed.
文摘Tim Berners-Lee developed the internet at CERN in early 1990 with fundamental technologies such as HTML,URL,and HTTP which became the foundation of the web.The contemporary web we use today has been much advanced over a period of time ever since the innovation of the World Wide Web was introduced.The static web was the first version of the web,which was the read-only web.Succeeding development in web technology is web 3.0 which is a distributed and decentralized web with emerging technologies.This article emphasizes the comparison of important details with the evolution of the web.The paper also demonstrates the transactional architecture of DApps in networks and decentralized state machines.Decentralization,connectivity,the semantic web,augmented reality and artificial intelligence are the signifi-cant features of web 3.0 technology.These features are tremendously used in decision-making on critical issues,which are discussed elaborately in the arti-cle.The paper provides various technologies to implement web 3.0 efficiently.The evolution of web 3.0 brings forth opportunities and challenges.The opportunities are the ownership of the data and a personalized web browsing experience.The main concerns are security and scalability requirements for blockchain transactions.The article also laid out the challenges that can be considered for further research.
基金supported by the National Natural Science Foundation of China(62032025,62002393)the Technology Program of Guangzhou,China(202103050004).
文摘Smart contract has been the core of blockchain systems and other blockchain-based systems since Blockchain 2.0.Various operations on blockchain are performed through the invocation and execution of smart contracts.This leads to extensive combinations between blockchain,smart contract,Internet of Things(IoT)and Cyber-Physical System(CPS)applications,and then many blockchain-based IoT or CPS applications emerge to provide multiple benefits to the economy and society.In this case,obtaining a better understanding of smart contracts will contribute to the easier operation,higher efficiency and stronger security of those blockchain-based systems and applications.Many existing studies on smart contract analysis are based on similarity calculation and smart contract classification.However,smart contract is a piece of code with special characteristics and most of smart contracts are stored without any category labels,which leads to difficulties of smart contract classification.As the back end of a blockchain-based Decentralized Application(DApp)is one or several smart contracts,DApps with labeled categories and open source codes are applied to achieve a supervised smart contract classification.A three-phase approach is proposed to categorize DApps based on various data features.In this approach,5,659 DApps with smart contract source codes and pre-tagged categories are first obtained based on massive collected DApps and smart contracts from Ethereum,State of the DApps and DappRadar.Then feature extraction and construction methods are designed to form multi-feature vectors that could present the major characteristics of DApps.Finally,a fused classification model consisting of KNN,XGBoost and random forests is applied to the multi-feature vectors of all DApps for performing DApp classification.The experimental results show that the method is effective.In addition,some positive correlations between feature variables and categories,as well as several user behavior patterns of DApp calls,are found in this paper.
基金This work was supported by the National Natural Science Foundation of China (No. 20301010) the Major State Basic Research Development Program (No. G2000077500) and the Foundation from Nanjing University
文摘The title compound [2-dapp]2[Zn(dmit)2] synthesized by the direct reaction of [Et4N]2[Zn(dmit)2] and [2-dapp]I crystallizes in monoclinic, space group P2l/c with a = 29.7436(6), b = l0.6266(3), c = l3.6161(4) ? b = 93.l16(l)? V = 4297.3 ?, Z = 4, Dc = 1.448 g/cm3, m = 1.091 mm-1 and F(000) = 1936. The structure was refined by fu1l-matrix 1east-squares methods to the final R = 0.075 and wR = 0.l16, revealing the zinc-bis (dmit) anions interact strongly with the planar cation, 2-dapp+, by the hydrogen bond C(l)H(lC)…S(7) (x, 3/2y, 1/2+z).
基金supported by the National High Technology Research and Development of China (863 Program) (2009AA03Z217)the National Natural Science Foundation of China (90922028)the Natural Science Foundation of Huaqiao University (09BS401)
文摘N-cetylpyridinium iodide (N-CPI) as a new electric additive for enhancing photovoltaic performance of the dye-sensitized solar cell (DSSC) was studied.It showed high efficiency for enhancing both the open-circuit voltage and the short-circuit current density of DSSC when the suitable amount of N-CPI as 0.02 M was added in liquid electrolyte.The energy conversion effi- ciency of DSSC increased from 4.429% to 6.535%,with 47.55% enhancement.Therefore,it is a highly efficient electric addi- tive for DSSC.The intrinsic reason is owing to the special molecular structure of N-CPI,which contains two different polarity groups.As a surfactant,N-CPI could form ordered arrangement in liquid electrolyte,which affects the diffusing ability and the redox reaction of I-/I3-,and further affects the photovoltaic performance of DSSC.
基金funded by the CRYPTOVOTING project,funded by Sardinia Region,call POR FESR Sardegna 2014–2020,Prot.0010083,no.1361 REA,August 01,2018,and by the ABATA project(Application of Blockchain to Authenticity and Traceability of Aliments)funded by Italian Ministry for Economic Development,National Operational Program“Enterprises and Competitiveness”,project No.F/200130/01–02/X45.
文摘Blockchain software development is becoming more and more important for any modern software developer and IT startup.Nonetheless,blockchain software production still lacks a disciplined,organized and mature development process,as demonstrated by the many and(in)famous failures and frauds occurred in recent years.In this paper we present ABCDE,a complete method addressing blockchain software development.The method considers the software integration among the blockchain components—smart contracts,libraries,data structures—and the out-of-chain components,such as web or mobile applications,which all together constitute a complete DApp system.We advocate for ABCDE the use of agile practices,because these are suited to develop systems whose requirements are not completely understood since the beginning,or tend to change,as it is the case of most blockchain-based applications.ABCDE is based on Scrum,and is therefore iterative and incremental.From Scrum,we kept the requirement gathering with user stories,the iterative-incremental approach,the key roles,and the meetings.The main difference with Scrum is the separation of development activities in two flows—one for smart contracts and the other for out-of-chain software interacting with the blockchain—each performed iteratively,with integration activities every 2–3 iterations.ABCDE makes explicit the activities that must be performed to design,develop,test and integrate smart contracts and out-of-chain software,and documents the smart contracts using formal diagrams to help development,security assessment,and maintenance.A diagram derived from UML class diagram helps to effectively model the data structure of smart contracts,whereas the exchange of messages between the entities of the system is modeled using a modified UML sequence diagram.The proposed method has also specific activities for security assessment and gas optimization,through systematic use of patterns and checklists.ABCDE focuses on Ethereum blockchain and its Solidity language,but preserves generality and with proper modifications might be applied to any blockchain software project.ABCDE method is described in detail,and an example is given to show how to concretely implement the various development steps.
