Ubiquitous computing must incorporate a certain level of security.For the severely resource constrained applications,the energy-efficient and small size cryptography algorithm implementation is a critical problem.Hard...Ubiquitous computing must incorporate a certain level of security.For the severely resource constrained applications,the energy-efficient and small size cryptography algorithm implementation is a critical problem.Hardware implementations of the advanced encryption standard(AES)for authentication and encryption are presented.An energy consumption variable is derived to evaluate low-power design strategies for battery-powered devices.It proves that compact AES architectures fail to optimize the AES hardware energy,whereas reducing invalid switching activities and implementing power-optimized sub-modules are the reasonable methods.Implementations of different substitution box(S-Boxes)structures are presented with 0.25μm 1.8 V CMOS(complementary metal oxide semiconductor)standard cell library.The comparisons and trade-offs among area,security,and power are explored.The experimental results show that Galois field composite S-Boxes have smaller size and highest security but consume considerably more power,whereas decoder-switch-encoder S-Boxes have the best power characteristics with disadvantages in terms of size and security.The combination of these two type S-Boxes instead of homogeneous S-Boxes in AES circuit will lead to optimal schemes.The technique of latch-dividing data path is analyzed,and the quantitative simulation results demonstrate that this approach diminishes the glitches effectively at a very low hardware cost.展开更多
In the field of cloud computing, topics such as computing resource virtualization, differences between grid and cloud computing, relationship between high-performance computers and cloud computing centers, and cloud s...In the field of cloud computing, topics such as computing resource virtualization, differences between grid and cloud computing, relationship between high-performance computers and cloud computing centers, and cloud security and standards have attracted much research interest. This paper analyzes these topics and highlights that resource virtualization allows information services to be scalable, intensive, and specialized; grid computing involves using many computers for large-scale computing tasks, while cloud computing uses one platform for multiple services; high-performance computers may not be suitable for a cloud computing; security in cloud computing focuses on trust management between service suppliers and users; and based on the existing standards, standardization of cloud computing should focus on interoperability between services.展开更多
Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method an...Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method and present the numerical results for the National Institute of Metrology （NIM） in Beijing, Laboratoire National de Metrologie et Essais-Systeme de References Temps-Espaee （LNE-SYRTE） in Paris and Physikalisch-Teehnische Bundesanstalt （PTB） in Braunschweig. The differences of the tidal relativistic red shift approach as large as 1.1 × 10^-16 when frequency standards at NIM are compared with those at SYRTE and PTB. Moreover, the tidal relativistic red shifts of frequency standards in space stations are also computed.展开更多
Accurate calculations of strongly correlated materials remain a formidable challenge in condensed matter physics,particularly due to the computational demand of conventional methods.This paper presents an efficient so...Accurate calculations of strongly correlated materials remain a formidable challenge in condensed matter physics,particularly due to the computational demand of conventional methods.This paper presents an efficient solver for dynamical mean field theory using configuration interaction(CI).The method is shown to have improved efficiency compared to traditional,exact diagonalization approaches.Hence,it provides an accessible,open-source alternative that can be executed on standard laptop computers or on supercomputers.The solver is demonstrated on cerium in theγ,αandϵphases.An analysis of how the electronic structure of Ce evolves as function of lattice compression is made.It is argued that the electronic structure evolves from a localized nature of the 4f shell in γ-Ce to an essentially itinerant nature of the 4f shell of ϵ-Ce.The transition between these two phases,as function of compression,can hence be seen as a Mott transition.However,this transition is intercepted by the strongly correlatedα-phase of elemental Ce,for which the 4f shell forms a Kondo singlet.展开更多
基金the"863"High Technology Research and Development Program of China(2006AA01Z226)the Scientific Research Foundation of Huazhong University of Science and Technology(2006Z011B)the Program for New Century Excellent Talents in University(NCET-07-0328).
文摘Ubiquitous computing must incorporate a certain level of security.For the severely resource constrained applications,the energy-efficient and small size cryptography algorithm implementation is a critical problem.Hardware implementations of the advanced encryption standard(AES)for authentication and encryption are presented.An energy consumption variable is derived to evaluate low-power design strategies for battery-powered devices.It proves that compact AES architectures fail to optimize the AES hardware energy,whereas reducing invalid switching activities and implementing power-optimized sub-modules are the reasonable methods.Implementations of different substitution box(S-Boxes)structures are presented with 0.25μm 1.8 V CMOS(complementary metal oxide semiconductor)standard cell library.The comparisons and trade-offs among area,security,and power are explored.The experimental results show that Galois field composite S-Boxes have smaller size and highest security but consume considerably more power,whereas decoder-switch-encoder S-Boxes have the best power characteristics with disadvantages in terms of size and security.The combination of these two type S-Boxes instead of homogeneous S-Boxes in AES circuit will lead to optimal schemes.The technique of latch-dividing data path is analyzed,and the quantitative simulation results demonstrate that this approach diminishes the glitches effectively at a very low hardware cost.
文摘In the field of cloud computing, topics such as computing resource virtualization, differences between grid and cloud computing, relationship between high-performance computers and cloud computing centers, and cloud security and standards have attracted much research interest. This paper analyzes these topics and highlights that resource virtualization allows information services to be scalable, intensive, and specialized; grid computing involves using many computers for large-scale computing tasks, while cloud computing uses one platform for multiple services; high-performance computers may not be suitable for a cloud computing; security in cloud computing focuses on trust management between service suppliers and users; and based on the existing standards, standardization of cloud computing should focus on interoperability between services.
基金Supported by the National Key R&D Program of China under Grant No 2016YFF0200200
文摘Frequencies of frequency standards are shifted by the local static gravity red shifts and also modulated by the tidal relativistic red shifts. We compute the tidal relativistic red shifts using a time-domain method and present the numerical results for the National Institute of Metrology （NIM） in Beijing, Laboratoire National de Metrologie et Essais-Systeme de References Temps-Espaee （LNE-SYRTE） in Paris and Physikalisch-Teehnische Bundesanstalt （PTB） in Braunschweig. The differences of the tidal relativistic red shift approach as large as 1.1 × 10^-16 when frequency standards at NIM are compared with those at SYRTE and PTB. Moreover, the tidal relativistic red shifts of frequency standards in space stations are also computed.
基金support from the Wallenberg Initiative Materials Science for Sustainability (WISE) funded by the Knut and Alice Wallenberg Foun- dation (KAW) and the European Research Council through the ERC Synergy Grant 854843-FASTCORRO.E. also acknowledges support from STandUPP, eSSENCE, the Swedish Research Council (VR) and the Knut and Alice Wallenberg Foundation (KAW- Scholar program)NL-ECO: Netherlands Initiative for Energy-Efficient Computing (with project number NWA. 1389.20.140) of the NWA research program.
文摘Accurate calculations of strongly correlated materials remain a formidable challenge in condensed matter physics,particularly due to the computational demand of conventional methods.This paper presents an efficient solver for dynamical mean field theory using configuration interaction(CI).The method is shown to have improved efficiency compared to traditional,exact diagonalization approaches.Hence,it provides an accessible,open-source alternative that can be executed on standard laptop computers or on supercomputers.The solver is demonstrated on cerium in theγ,αandϵphases.An analysis of how the electronic structure of Ce evolves as function of lattice compression is made.It is argued that the electronic structure evolves from a localized nature of the 4f shell in γ-Ce to an essentially itinerant nature of the 4f shell of ϵ-Ce.The transition between these two phases,as function of compression,can hence be seen as a Mott transition.However,this transition is intercepted by the strongly correlatedα-phase of elemental Ce,for which the 4f shell forms a Kondo singlet.
