Street dusts collected from 20 sites as well as three special dust samples collected from chimney of coal-fired plant, smelter and refinery of nonferrous metals and automobile exhaust, respectively, in the Chang-Zhu-T...Street dusts collected from 20 sites as well as three special dust samples collected from chimney of coal-fired plant, smelter and refinery of nonferrous metals and automobile exhaust, respectively, in the Chang-Zhu-Tan (Changsha, Zhuzhou and Xiangtan) urban region, Hunan, China, in May to August 2009, were investigated for sources of polycylic aromatic hydrocarbons (PAHs). The ΣPAHs16 levels were in the range of 3515 - 24488 ng/g, with a mean of 8760 ng/g. The sources of PAH inputs to street dusts were determined by isomer ratios, principal components analysis and REE geochemical analysis. The isomer ratios suggested a rather uniform mixture of coal combustion and petroleum PAH sources. Factor analysis indicated that the main sources of 16 PAHs were coal combustion/vehicle exhaust and coking/ petroleum. Rare earth elements (REE) and Factor score analysis further indicated the possible dust sources were from background soil, coal or coking combustion, nonferrous metal factories, traffic exhaust.展开更多
An effective and secure system used for evidence preservation is essential to possess the properties of anti- loss, anti-forgery, anti-tamper and perfect verifiability. Traditional architecture which relies on central...An effective and secure system used for evidence preservation is essential to possess the properties of anti- loss, anti-forgery, anti-tamper and perfect verifiability. Traditional architecture which relies on centralized cloud storage is depressingly beset by the security problems such as incomplete confidence and unreliable regulation. Moreover, an expensive, inefficient and incompatible design impedes the effort of evidence preservation. In contrast, the decentralized blockchain network is qualified as a perfect replacement for its secure anonymity, irrevocable commitment, and transparent traceability. Combining with subliminal channels in blockchain, we have weaved the transaction network with newly designed evidence audit network. In this paper, we have presented and implemented a lightweight digital evidence-preservation architecture which possesses the features of privacy-anonymity, audit-transparency, function-scalability and operation-lightweight. The anonymity is naturally formed from the cryptographic design, since the cipher evidence under encrypted cryptosystem and hash-based functions leakages nothing to the public. Covert channels are efficiently excavated to optimize the cost, connectivity and security of the framework, transforming the great computation power of Bitcoin network to the value of credit. The transparency used for audit, which relates to the proof of existence, comes from instant timestamps and irreversible hash functions in mature blockchain network. The scalability is represented by the evidence chain interacted with the original blockchain, and the extended chains on top of mainchain will cover the most of auditors in different institutions. And the lightweight, which is equal to low-cost, is derived from our fine-grained hierarchical services. At last, analyses of efficiency, security, and availability have shown the complete accomplishment of our system.展开更多
The early history of Earth is poorly understood,due to the lack of ancient rocks formed after the formation of the newborn Earth,especiallyfor thefirst 500 million years(Hadean Eon).To our knowledge,this period is the...The early history of Earth is poorly understood,due to the lack of ancient rocks formed after the formation of the newborn Earth,especiallyfor thefirst 500 million years(Hadean Eon).To our knowledge,this period is the most geodynamically vigorous in the crustal evolution history of Earth[1],and is characterized by intense collision with meteorites and the formation of a global magma ocean(~4.41 Ga;cf.review article by Ref.[2]).展开更多
Approaches to apply graph computing to power grid analysis are systematically explained using real-world application examples.Through exploring the nature of the power grid and the characteristics of power grid analys...Approaches to apply graph computing to power grid analysis are systematically explained using real-world application examples.Through exploring the nature of the power grid and the characteristics of power grid analysis,the guidelines for selecting appropriate graph computing techniques for the application to power grid analysis are outlined.A custom graph model for representing the power grid for the analysis and simulation purpose and an in-memory computing(IMC)based graph-centric approach with a shared-everything architecture are introduced.Graph algorithms,including network topology processing and subgraph processing,and graph computing application scenarios,including in-memory computing,contingency analysis,and Common Information Model(CIM)model merge,are presented.展开更多
Traditional public key infrastructure(PKI)only provides authentication for network communication,and the standard X.509 certificate used in this architecture reveals the user’s identity.This lack of privacy protectio...Traditional public key infrastructure(PKI)only provides authentication for network communication,and the standard X.509 certificate used in this architecture reveals the user’s identity.This lack of privacy protection no longer satisfies the increasing demands for personal privacy.Though an optimized anonymous PKI certificate realizes anonymity,it has the potential to be abused due to the lack of identity tracking.Therefore,maintaining a balance between user anonymity and traceability has become an increasing requirement for current PKI.This paper introduces a novel traceable self-randomization certificate authentication scheme based on PKI architecture that achieves both anonymity and traceability.We propose a traceable self-randomization certificate authentication scheme based on the short randomizable signature.Specifically,certificate users can randomize the initial certificate and public key into multiple anonymous certificates and public keys by themselves under the premise of traceability,which possesses lower computational complexity and fewer interactive operations.Users can exhibit different attributes of themselves in different scenarios,randomizing the attributes that do not necessarily need to be displayed.Through security and performance analysis,we demonstrate the suitability of the improved PKI architecture for practical applications.Additionally,we provide an application of the proposed scheme to the permissioned blockchain for supervision.展开更多
Hierarchical Identity-Based Broadcast Encryption （HIBBE） organizes users into a tree-like structure, and it allows users to delegate their decryption ability to subordinates and enable encryption to any subset of us...Hierarchical Identity-Based Broadcast Encryption （HIBBE） organizes users into a tree-like structure, and it allows users to delegate their decryption ability to subordinates and enable encryption to any subset of users while only intended users can decrypt. However, current HIBBE schemes do not support efficient revocation of private keys. Here, a new primitive called Revocable Hierarchical Identity-Based Broadcast Encryption （RHIBBE） is formalized that allows revocation of the HIBBE. Ciphertext indistinguishability is defined against the selectively Bounded Revocable Identity-Vector-Set and Chosen-Plaintext Attack （IND-sBRIVS-CPA）. An IND-sBRIVS-CPA secure RHIBBE scheme is constructed with efficient revocation on prime-order bilinear groups. The unbounded version of the scheme is also shown to be secure but a little weaker than the former under the decisional n-Weak Bilinear Diffie-Hellman inversion assumption.展开更多
This paper presents a flexible radio-frequency microelectromechanical system(RF MEMS)switch integrated on cyclo-olefin polymer(COP)substrate using a modified surface MEMS processing technology,which could be used in t...This paper presents a flexible radio-frequency microelectromechanical system(RF MEMS)switch integrated on cyclo-olefin polymer(COP)substrate using a modified surface MEMS processing technology,which could be used in the 17-19 GHz frequency band of satellite communication.Through systematic simulation analysis,it is found that flexible RF MEMS switch can achieve certain bending radius by miniaturizing the electronic dimension,without degrading the RF performance.It is demonstrated that the RF characteristics of flexible RF MEMS switch with special anchor structural design,fabricated by modified surface MEMS processing,are not sensitive to bending deformation under the curvature of 0 mm^(-1),0.05 mm^(-1),0.10 mm^(-1).Furthermore,the range of bending curvature which will affect the RF characteristics is given through systematic simulation.The flexible RF MEMS switch with high process compatibility and stable RF performance is believed to be promising candidates for future microwave communications and other consumer electronics.展开更多
The communication efficiency optimization,censorship resilience,and generation of shared randomness are inseparable from the threshold cryptography in the existing Byzantine Fault Tolerant(BFT)consensus.The membership...The communication efficiency optimization,censorship resilience,and generation of shared randomness are inseparable from the threshold cryptography in the existing Byzantine Fault Tolerant(BFT)consensus.The membership in consensus in a blockchain scenario supports dynamic changes,which effectively prevents the corruption of consensus participants.Especially in cross-chain protocols,the dynamic access to different blockchains will inevitably bring about the demand for member dynamic.Most existing threshold cryptography schemes rely on redefined key shares,leading to a static set of secret sharing participants.In this paper,we propose a general approach to coupling blockchain consensus and dynamic secret sharing.The committee performs consensus confirmation of both dynamic secret sharing and transaction proposals.Our scheme facilitates threshold cryptography membership dynamic,thus underlying support for membership dynamic of threshold cryptographybased BFT consensus schemes.We instantiate a dynamic HotStuff consensus to demonstrate the effectiveness of the scheme.After the correctness and security proof,our scheme achieves the secrecy and integrity of the threshold key shares while ensuring consensus liveness and safety.Experimental results prove that our scheme obtains dynamic membership with negligible overhead.展开更多
文摘Street dusts collected from 20 sites as well as three special dust samples collected from chimney of coal-fired plant, smelter and refinery of nonferrous metals and automobile exhaust, respectively, in the Chang-Zhu-Tan (Changsha, Zhuzhou and Xiangtan) urban region, Hunan, China, in May to August 2009, were investigated for sources of polycylic aromatic hydrocarbons (PAHs). The ΣPAHs16 levels were in the range of 3515 - 24488 ng/g, with a mean of 8760 ng/g. The sources of PAH inputs to street dusts were determined by isomer ratios, principal components analysis and REE geochemical analysis. The isomer ratios suggested a rather uniform mixture of coal combustion and petroleum PAH sources. Factor analysis indicated that the main sources of 16 PAHs were coal combustion/vehicle exhaust and coking/ petroleum. Rare earth elements (REE) and Factor score analysis further indicated the possible dust sources were from background soil, coal or coking combustion, nonferrous metal factories, traffic exhaust.
基金This work is supported by the National Key Research and Development Program of China under Grant No. 2017YFB0802500, the National Natural Science Foundation of China under Grant Nos. 61772538, 61672083, 61370190, 61532021, 61472429, and 61402029, and the National Cryptography Development Fund of China under Grant No. MMJJ20170106.
文摘An effective and secure system used for evidence preservation is essential to possess the properties of anti- loss, anti-forgery, anti-tamper and perfect verifiability. Traditional architecture which relies on centralized cloud storage is depressingly beset by the security problems such as incomplete confidence and unreliable regulation. Moreover, an expensive, inefficient and incompatible design impedes the effort of evidence preservation. In contrast, the decentralized blockchain network is qualified as a perfect replacement for its secure anonymity, irrevocable commitment, and transparent traceability. Combining with subliminal channels in blockchain, we have weaved the transaction network with newly designed evidence audit network. In this paper, we have presented and implemented a lightweight digital evidence-preservation architecture which possesses the features of privacy-anonymity, audit-transparency, function-scalability and operation-lightweight. The anonymity is naturally formed from the cryptographic design, since the cipher evidence under encrypted cryptosystem and hash-based functions leakages nothing to the public. Covert channels are efficiently excavated to optimize the cost, connectivity and security of the framework, transforming the great computation power of Bitcoin network to the value of credit. The transparency used for audit, which relates to the proof of existence, comes from instant timestamps and irreversible hash functions in mature blockchain network. The scalability is represented by the evidence chain interacted with the original blockchain, and the extended chains on top of mainchain will cover the most of auditors in different institutions. And the lightweight, which is equal to low-cost, is derived from our fine-grained hierarchical services. At last, analyses of efficiency, security, and availability have shown the complete accomplishment of our system.
基金supported by the Chinese Postdoctoral Science Foundation (2022M710876)the Natural Science Foundation of Anhui Province (2108085MD133)+1 种基金the China Geological Survey (DD20190154 and DD20221689)the PI Project of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2020GD0802)。
文摘The early history of Earth is poorly understood,due to the lack of ancient rocks formed after the formation of the newborn Earth,especiallyfor thefirst 500 million years(Hadean Eon).To our knowledge,this period is the most geodynamically vigorous in the crustal evolution history of Earth[1],and is characterized by intense collision with meteorites and the formation of a global magma ocean(~4.41 Ga;cf.review article by Ref.[2]).
基金supported by National Natural Science Foundation of China under the Grant U1766214.
文摘Approaches to apply graph computing to power grid analysis are systematically explained using real-world application examples.Through exploring the nature of the power grid and the characteristics of power grid analysis,the guidelines for selecting appropriate graph computing techniques for the application to power grid analysis are outlined.A custom graph model for representing the power grid for the analysis and simulation purpose and an in-memory computing(IMC)based graph-centric approach with a shared-everything architecture are introduced.Graph algorithms,including network topology processing and subgraph processing,and graph computing application scenarios,including in-memory computing,contingency analysis,and Common Information Model(CIM)model merge,are presented.
基金This work was supported by the National Key R&D Program of China(No.2020YFB1005600)Beijing Natural Science Foundation(No.M21031)+4 种基金the Natural Science Foundation of China(Nos.U21A20467,61932011,62002011,and 61972019)the Populus Euphratica Foundation(No.CCF-HuaweiBC2021009)the Open Research Fund of Key Laboratory of Cryptography of Zhejiang Province(No.ZCL21007)Zhejiang Soft Science Research Program(No.2023C35081)the Youth Top Talent Support Program of Beihang University(No.YWF-22-L-1272).
文摘Traditional public key infrastructure(PKI)only provides authentication for network communication,and the standard X.509 certificate used in this architecture reveals the user’s identity.This lack of privacy protection no longer satisfies the increasing demands for personal privacy.Though an optimized anonymous PKI certificate realizes anonymity,it has the potential to be abused due to the lack of identity tracking.Therefore,maintaining a balance between user anonymity and traceability has become an increasing requirement for current PKI.This paper introduces a novel traceable self-randomization certificate authentication scheme based on PKI architecture that achieves both anonymity and traceability.We propose a traceable self-randomization certificate authentication scheme based on the short randomizable signature.Specifically,certificate users can randomize the initial certificate and public key into multiple anonymous certificates and public keys by themselves under the premise of traceability,which possesses lower computational complexity and fewer interactive operations.Users can exhibit different attributes of themselves in different scenarios,randomizing the attributes that do not necessarily need to be displayed.Through security and performance analysis,we demonstrate the suitability of the improved PKI architecture for practical applications.Additionally,we provide an application of the proposed scheme to the permissioned blockchain for supervision.
基金supported by the National Key Research and Development Program of China (No. 2017YFB0802502)the National Natural Science Foundation of China (Nos. 61672083, 61370190, 61532021, 61472429, 61402029, 61702028, and 61571024)+3 种基金the National Cryptography Development Fund (No. MMJJ20170106)the Planning Fund Project of Ministry of Education (No. 12YJAZH136)the Beijing Natural Science Foundation (No. 4132056)the Fund of the State Key Laboratory of Information Security, the Institute of Information Engineering, and the Chinese Academy of Sciences (No. 2017-MS-02)
文摘Hierarchical Identity-Based Broadcast Encryption （HIBBE） organizes users into a tree-like structure, and it allows users to delegate their decryption ability to subordinates and enable encryption to any subset of users while only intended users can decrypt. However, current HIBBE schemes do not support efficient revocation of private keys. Here, a new primitive called Revocable Hierarchical Identity-Based Broadcast Encryption （RHIBBE） is formalized that allows revocation of the HIBBE. Ciphertext indistinguishability is defined against the selectively Bounded Revocable Identity-Vector-Set and Chosen-Plaintext Attack （IND-sBRIVS-CPA）. An IND-sBRIVS-CPA secure RHIBBE scheme is constructed with efficient revocation on prime-order bilinear groups. The unbounded version of the scheme is also shown to be secure but a little weaker than the former under the decisional n-Weak Bilinear Diffie-Hellman inversion assumption.
基金supported by BOE Technology Group Co.,Ltd.Y.L.acknowledges support from the National Natural Science Foundation of China under grant numbers 61825102 and U21A20460.
文摘This paper presents a flexible radio-frequency microelectromechanical system(RF MEMS)switch integrated on cyclo-olefin polymer(COP)substrate using a modified surface MEMS processing technology,which could be used in the 17-19 GHz frequency band of satellite communication.Through systematic simulation analysis,it is found that flexible RF MEMS switch can achieve certain bending radius by miniaturizing the electronic dimension,without degrading the RF performance.It is demonstrated that the RF characteristics of flexible RF MEMS switch with special anchor structural design,fabricated by modified surface MEMS processing,are not sensitive to bending deformation under the curvature of 0 mm^(-1),0.05 mm^(-1),0.10 mm^(-1).Furthermore,the range of bending curvature which will affect the RF characteristics is given through systematic simulation.The flexible RF MEMS switch with high process compatibility and stable RF performance is believed to be promising candidates for future microwave communications and other consumer electronics.
基金supported by the National Key R&D Program of China(2020YFB1005600)the Beijing Natural Science Foundation(M21031)+3 种基金the Natural Science Foundation of China through projects(U21A20467,61932011,62002011,61972019)the Populus euphratica found(CCF-HuaweiBC2021009)the Open Research Fund of Key Laboratory of Cryptography of Zhejiang Province(ZCL21007)the Youth Top Talent Support Program of Beihang University(YWF-22-L-1272).
文摘The communication efficiency optimization,censorship resilience,and generation of shared randomness are inseparable from the threshold cryptography in the existing Byzantine Fault Tolerant(BFT)consensus.The membership in consensus in a blockchain scenario supports dynamic changes,which effectively prevents the corruption of consensus participants.Especially in cross-chain protocols,the dynamic access to different blockchains will inevitably bring about the demand for member dynamic.Most existing threshold cryptography schemes rely on redefined key shares,leading to a static set of secret sharing participants.In this paper,we propose a general approach to coupling blockchain consensus and dynamic secret sharing.The committee performs consensus confirmation of both dynamic secret sharing and transaction proposals.Our scheme facilitates threshold cryptography membership dynamic,thus underlying support for membership dynamic of threshold cryptographybased BFT consensus schemes.We instantiate a dynamic HotStuff consensus to demonstrate the effectiveness of the scheme.After the correctness and security proof,our scheme achieves the secrecy and integrity of the threshold key shares while ensuring consensus liveness and safety.Experimental results prove that our scheme obtains dynamic membership with negligible overhead.
