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A New Feistel-Type White-Box Encryption Scheme

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Journal of Computer Science & Technology 2017年第2期32卷 386-395页

作者： Ting-Ting Lin Xue-jia Lai Wei-jia Xue yin jia Cryptography and Information Security Laboratory Department of Computer Science Shanghai Jiao Tong University Shanghai 200240 China Irdeto Canada Ottawa Ontario K2K3G5 Canada

The white-box attack is a new attack context in which it is assumed that cryptographic software is implemented on an un-trusted platform and all the implementation details are controlled by the attackers. So far, almost all white-box solutions have been broken. In this study, we propose a white-box encryption scheme that is not a variant of obfuscating existing ciphers but a completely new solution. The new scheme is based on the unbalanced Feistel network as well as the ASASASA （where ＂A＂ means affine, and ＂S＂ means substitution） structure. It has an optional input block size and is suitable for saving space compared with other solutions because the space requirement grows slowly （linearly） with the growth of block size. Moreover, our scheme not only has huge white-box diversity and white-box ambiguity but also has a particular construction to bypass public white-box cryptanalysis techniques, including attacks aimed at white-box variants of existing ciphers and attacks specific to the ASASASA structure. More precisely, we present a definition of white-box security with regard to equivalent key, and prove that our scheme satisfies such security requirement.

关键词： white-box equivalent key Feistel network cryptography ASASASA

Error estimates of numerical methods for the nonlinear Dirac equation in the nonrelativistic limit regime

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Science China Mathematics 2016年第8期59卷 1461-1494页

作者： BAO WeiZhu CAI YongYong jia XiaoWei yin jia Department of Mathematics National University of SingaporeSingapore 119076Singapore Beijing Computational Science Research Center Beijing 100193China Department of Mathematics Purdue UniversityWest LafayetteIN 47907USA NUS Graduate School for Integrative Sciences and Engineering(NGS) National University of SingaporeSingapore 117456Singapore

We present several numerical methods and establish their error estimates for the discretization of the nonlinear Dirac equation （NLDE） in the nonrelativistic limit regime, involving a small dimensionless parameter 0 〈 ε〈〈1 which is inversely proportional to the speed of light. In this limit regime, the solution is highly oscillatory in time, i.e., there are propagating waves with wavelength O（ ε^2） and O（1） in time and space, respectively. We begin with the conservative Crank-Nicolson finite difference （CNFD） method and establish rigorously its error estimate which depends explicitly on the mesh size h and time step τ- as well as the small parameter 0 〈 ε≤1 Based on the error bound, in order to obtain ＇correct＇ numerical solutions in the nonrelativistic limit regime, i.e., 0 〈 ε≤1 , the CNFD method requests the ε-scalability： τ- = O（ε3） and h = O（√ε）. Then we propose and analyze two numerical methods for the discretization of NLDE by using the Fourier spectral discretization for spatial derivatives combined with the exponential wave integrator and time- splitting technique for temporal derivatives, respectively. Rigorous error bounds for the two numerical methods show that their ε-scalability is improved to τ = O（ε2） and h = O（1） when 0 〈 ε 〈〈 1. Extensive numerical results are reported to confirm our error estimates.

关键词： nonlinear Dirac equation nonrelativistic limit regime Crank-Nicolson finite difference method exponential wave integrator time splitting spectral method ^-scalability

Specification and Verification of the Zab Protocol with TLA+

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Journal of Computer Science & Technology 2020年第6期35卷 1312-1323页

作者： jia-Qi yin Hui-Biao Zhu Yuan Fei Shanghai Key Laboratory of Trustworthy Computing East China Normal UniversityShanghai 200062China College of Information Mechanical and Electrical EngineeringShanghai Normal UniversityShanghai 200234China

ZooKeeper Atomic Broadcast (Zab) is an atomic broadcast protocol specially designed for ZooKeeper, which supports additional crash recovery. This protocol actually has been widely adopted by famous Internet companies, but there are few studies on the correctness and credibility of the Zab protocol, and thus we utilize formal methods to study the correctness. In this paper, Zab, Paxos and Raft are all analyzed and compared to help better understand the Zab protocol. Then we model the Zab protocol with TLA+ and verify three properties abstracted from the specification by the model checker TLC, including two liveness properties and one safety property. The final experimental results can prove that the design of the protocol conforms to the original requirements. This paper makes up for the analysis of formal methods in the Zab protocol.

关键词： Zab protocol TLA+ specification verification

An approximately analytical solution method for the cable-driven parallel robot in FAST

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Research in Astronomy and Astrophysics 2021年第2期21卷 169-179页

作者： jia-Ning yin Peng jiang Rui Yao National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the largest single-dish aperture telescope with a cable-driven parallel robot introduced to achieve the highest sensitivity in the ***,to realize the high-precision,mechanical equations of such a robot are always complicated,so that it is difficult to achieve real-time control by the traditional iterative *** this regard,this paper proposes an approximately analytical solution method,which uses the approximately linear relationship between the main parameters of FAST to bypass some *** the coefficients of the relationship extracted,static or quasi-static mechanical equations can be analytically *** this paper’s example,this method saves at least 90%of the calculating time and the calculated values are consistent with the experimental *** such huge efficiency improvements,real-time and high-precision control of the FAST will no longer be difficult ***,all the work in this paper is expected to be used in the FAST.

关键词： telescopes-methods analytical-instrumentation miscellaneous

Experimental Investigation of Bubble Behaviors in Subcooled Flow Boiling

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Journal of Thermal Science 2012年第2期21卷 184-188页

作者： Peng Guan Li jia Liaofei yin Shuo Wang Department of Power Engineering School of Mechanical and Electronic Control Engineering Beijing Jiaotong Univer-sity Shangyuancun No.3 100044 Beijing China

The experimental investigation on vapor bubble growth is performed for analyzing subcooled boiling in a vertical annular channel with inner heating surface and upward water flow under atmospheric pressure. Bulk liquid mass flux ranges from 79 kg/m2s to 316 kg/m2s, and subcooling is from 40 K to 60 K. The bubble behaviors from inception to collapse are captured by High-speed photography. The performance of bubble growth recorded by the high-speed photography is given in this paper. The bubble behaviors, effect of the bubble slippage on the heat transfer, and various forces acting on the bubble are discussed.

关键词： subcooled boiling annular channel bubble behaviors visualization

Rapid chemical recycling of waste polyester plastics catalyzed by recyclable catalyst

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Green Chemical Engineering 2024年第2期5卷 257-265页

作者： Yu-Ji Luo jia-yin Sun Zhi Li School of Physical Science and Technology ShanghaiTech UniversityShanghai201210China

Waste plastics are serious environmental threats due to their low degradability and low recycling *** and efficient waste plastics recycling technologies are urgently demanded for a sustainable ***,we report a rapid,closed-loop,and streamlined process to convert polyesters such as poly(ethylene terephthalate)(PET)back to its purified *** trifluoromethanesulfonic acid or metal triflates as the recyclable catalyst,polyesters such as PET can be completely depolymerized by simple carboxylic acids within 1 *** coupling this acidolysis with a subsequent hydrogenolysis process,the consumed carboxylic acid was recovered and the closed-loop of PET depolymerization could be *** catalysts and depolymerization agents are fully recycled while only PET and hydrogen are consumed.

关键词： Chemical recycling Waste polyester plastics Acidolysis Recyclable catalyst

Kinematics and forces of a flexible body in Karman vortex street

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Chinese Science Bulletin 2009年第4期54卷 556-561页

作者： WANG Siying jia LaiBing yin XieZhen Department of Modern Mechanics University of Science and Technology of China Hefei Anhui 230027 China

Experiments of a flexible filament in the wake of a cylinder and in free stream were conducted in a vertical soap film tunnel. The experiments distinctly visualized the movement of the filament. Based on the experimental kinematic results, a 2-d panel method was used to calculate the forces acting on the filament. The experiment and numerical results revealed that different from that in free stream, the filament in Karman vortex street flapped at the same frequency as the vortex street, and with smaller amplitude and larger curvature. The filament suffered an evident thrust in Karman vortex street, while a drag appeared in the case of free stream. The dependence of the drag coefficient on the phase relation between the movement of the filament and the Karman vortex street was also studied.

关键词：卡曼旋涡流柔韧细丝肥皂膜阻力系数

Cooling γ′ precipitation behavior and strengthening in powder metallurgy su-peralloy FGH4096

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Rare Metals 2008年第4期27卷 410-417页

作者： TIAN Gaofeng jia Chengchang WEN yin LIU Guoquan HU Benfu School of Materials Science and Engineering University of Science and Technology Beifing Beifing 100083 China

Two cooling schemes （continuous cooling and interrupted cooling tests） were applied to investigate the cooling γ precipitation behavior in powder metallurgy superalloy FGH4096. The effect of cooling rate on cooling γ precipitation and the development of γ precipitates during cooling process were involved in this study. The ultimate tensile strength （ErrS） of the specimens in various cooling circumstances was tested. The experiential equations were obtained between the average sizes of secondary and tertiary γ precipitates, the strength, and cooling rate. The results show that they are inversely correlated with the cooling rate as well as the grain boundary changes from serrated to straight, the shape of secondary γ precipitates changes from irregular cuboidal to spherical, while the formed tertiary γ precipitates are always spherical. The interrupted cooling tests show that the average size of secondary γ precipitates increases as a linear function of interrupt temperature for a fixed cooling rate of 24℃/min. The strength first decreases and then increases against interrupt temperature, which is fundamentally caused by the multistage nucleation of γ precipitates during cooling process.

关键词： nickel-base superalloy powder metallurgy (P/M) γ precipitates cooling rate heat treatment

Characteristics of sewage sludge and distribution of heavy metal in plants with amendment of sewage sludge

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Journal of Environmental Sciences 2006年第6期18卷 1094-1100页

作者： DAI jia-yin CHEN Ling ZHAO jian-fu MA Na Institute of Zoology Chinese Academy of Sciences Beijing 100080 China State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and Engineering Tongji University Shanghai 200092 China

In order to better understand land application of sewage sludge, the characterization of heavy metals and organic pollutants were investigated in three different sewage sludges in Shanghai City, China. It was found that the total concentrations of Cd in all of sewage sludge and total concentrations of Zn in Jinshan sewage sludge, as well as those ofZn, Cu, and Ni in Taopu sludge are higher than Chinese regulation limit of pollutants for sludge to be used in agriculture. Leachability of rig in all of studied samples and that of Cd in Taopu sewage sludge exceed the limit values of waste solid extraction standard in China legislation. Based on the characteristics for three kinds of sewage sludge, a pot experiment was conducted to investigate the effect of soil amended with Quyang sewage sludge on the accumulation of heavy *** Begonia semperfloreas-hybr; Ophiopogon japonicas （L.F.） Ker-Gaw; Loropetalum chindense-var, rubrum; Dendranthema morifolium; Viola tricolor; A ntirrhinum majas; Buxas radicans Sieb; Viburnum macrocephalum; Osmanthas fragrans Lour; Cinnamomum camphora siebold and Ligustrum lucidum ait. Results showed that 8 species of plant survived in the amended soil, and moreover they flourished as well as those cultivated in the control soil. The heavy metal concentration in plants varied with species, As, Pb, Cd and Cr concentration being the highest in the four herbaceous species studied, particularly in the roots of D. morifolium. These plants, however, did not show accumulator of As, Pb, Cd and Cr. The highest concentration of Ni and Hg was found in the roots ofD. morifolium, followed by the leaves ofB. semperflorens-hybr. Levels of Zn and Cu were much higher in D. morifolium than in the other plant species. D. morifolium accumulated Ni, Hg, Cu and Zn, which may contribute to the decrease of heavy metal contents in the amended soil. Treatment with sewage sludge did not significantly affect the uptake of heavy metals by the L. chindense-var, rubrum, ho

关键词： sewage sludge characteristic lixiviation test pot experiments land application