2,117 research outputs found

    Secure end-to-end browsing system with mobile composition

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    To fix the more and more serious leakage problem in remote access to confidential data, the paper designs and implements a secure end-to-end browsing system with mobile composition. It enables mobile-authenticated users to browse confidential files stored at server side using their personal computers securely. The authentication function is in real-time such that the system can stop the browsing function once it detects that the authenticated mobile is out of the communication range of user's personal computer. © 2011 IEEE.published_or_final_versio

    Efficient key integrity verification for quantum cryptography using combinatorial group testing

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    Quantum Information and Computation VIII 77020F (April 23, 2010)In quantum cryptography, the key can be directly distributed to the communicating parties through the communication channel. The security is guaranteed by the quantum properties of the channel. However, the transmitted key may contain errors due to the noise of the channel. Key integrity verification is an indispensable step in quantum cryptography and becomes an important problem in higher speed systems. Computing only one hash value for the key string does not provide an effective solution as it may lead to dropping all the bits once the hash values on both sides do not agree. In this paper, we introduce a new idea of using the technique of combinatorial group testing, which seems to be an unrelated topic, to design a scheme to identify the error bits to avoid dropping all the bits. Our scheme can precisely locate the error bits if the number of error bits is within the maximum set by the scheme while the overhead is insignificant based on our experiments (additional bits: 0.1% of the key; time for computing the hash values: 16ms; verification time: 22 ms). Also, even if the number of error bits is higher than the maximum set by the scheme, only some correct bits may be misclassified as error bits but not the vice versa. The results show that we can still keep the majority of the correct bits (e.g. the bits discarded due to misclassification is only 5% of the whole string even if the number of error bits is 10 times of the maximum). © 2010 SPIE.published_or_final_versionThe 2010 SPIE Conference on Defense, Security, and Sensing, Orlando, FL., 5 April 2010. In Proceedings of SPIE - The International Society for Optical Engineering, v. 7702, p. 77020F-1 - 77020F-

    An incremental shifting vector approach for reliability-based design optimization

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    © 2015, Springer-Verlag Berlin Heidelberg. This paper proposes a decoupling algorithm for reliability-based design optimization (RBDO) with high performance in terms of efficiency and convergence, which provides an effective tool for reliability design of many complex structures. The algorithm proceeds by performing a shifting vector calculation and then solving a deterministic design optimization in each step, and eventually converges to the optimal solution. An incremental shifting strategy is proposed to ensure stable convergence in the iteration process. In each step, the shifting vector preserves the information from the previous step, and only an adjustment is made for it through a shifting vector increment. A computation method is given for the shifting vector increment, avoiding solving an optimization problem during the reliability analysis and thus greatly reducing the computational cost of the iteration process. Six numerical examples and two engineering applications are presented to validate the effectiveness of the method proposed in this paper

    Wave dynamic processes induced by a supersonic projectile dischargingfrom a shock tube

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    A numerical study on wave dynamic processes occurring in muzzle blast flows, which are created by a supersonic projectile released from the open-end of a shock tube into ambient air, is described in this paper. The Euler equations, assuming axisymmetric flows, are solved by using a dispersion-controlled scheme implemented with moving boundary conditions. Three test cases are simulated for examining friction effects on the muzzle flow. From numerical simulations, the wave dynamic processes, including two blast waves, two jet flows, the bow shock wave and their interactions in the muzzle blasts, are demonstrated and discussed in detail. The study shows that the major wave dynamic processes developing in the muzzle flow remain similar when the friction varies, but some wave processes, such as shock-shock interactions, shock-jet interactions and the contact surface instability, get more intensive, which result in more complex muzzle blast flows.</p

    A dual cube hashing scheme for solving LPP integrity problem

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    In digital forensics, data stored in a hard disk usually contains valuable evidence. Preserving the integrity of the data in the hard disk is a critical issue. A single hash value for the whole hard disk is not appropriate as the investigation may take a long time and latent sector errors (LSEs) (bad sectors due to media imperfection, for example) which cause a sector suddenly unreadable will make the hash value inconsistent. On the other hand, using a hash per sector may need to store a lot of hash values. Previous research has been conducted to use fewer hash values, but can resist some of LSEs to decrease the number of unverifiable sectors even if there are LSEs. This integrity problem is more complicated in the presence of Legal Professional Privileged (LPP) data inside a seized hard disk in digital forensic as the hard disk has to be cloned once seized and the original hard disk will be sealed after cloning. Hash values need to be computed during this cloning process. However, the cloned copy will be returned to the suspect for the deletion of LPP data before the investigator can work on the sanitized copy. Thus, the integrity of unmodified sectors has to be verified using the hash values computed based on the original hard disk. This paper found that existing schemes are not good enough to solve the integrity problem in the presence of both LSEs and deletion of LPP data. We then propose the idea of a "Dual Cube" hashing scheme to solve the problem. The experiments show the proposed scheme performs better than the previous schemes and fits easily into the digital forensic procedure. © 2011 IEEE.published_or_final_versionThe 6th International Workshop on Systematic Approaches to Digital Forensic Engineering In conjunction with the IEEE Security and Privacy Symposium (IEEE/SADFE 2011), Oakland, CA., 26 May 2011. In IEEE/SADFE Proceedings, 2011, p. 1-

    Numerical simulation of deflagration to detonation transition in a straight duct: Effects of energy release and detonation stability

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    Numerical simulation based on the Euler equation and one-step reaction model is carried out to investigate the process of deflagration to detonation transition (DDT) occurring in a straight duct. The numerical method used includes a high resolution fifth-order weighted essentially non-oscillatory (WENO) scheme for spatial discretization, coupled with a third order total variation diminishing Runge-Kutta time stepping method. In particular, effect of energy release on the DDT process is studied. The model parameters used are the heat release at q = 50,30,25,20,15,10 and 5, the specific heat ratio at 1.2, and the activation temperature at Ti = 15, respectively. For all the cases, the initial energy in the spark is about the same compared to the detonation energy at the Chapman-Jouguet (CJ) state. It is found from the simulation that the DDT occurrence strongly depends on the magnitude of the energy release. The run-up distance of DDT occurrence decreases with the increase of the energy release for q = 50 similar to 20, and increases with the increase of the energy release for q = 20 similar to 5. This phenomenon is found to be in agreement with the analysis of mathematical stability theory. It is suggested that the factors to strengthen the DDT would make the detonation more stable, and vice versa. Finally, it is concluded from the simulations that the interaction of the shock wave and the flame front is the main reason for leading to DDT.</font

    基础地理数据库的持续更新问题

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    Author name used in this publication: 陈军Author name used in this publication: LI Zhi-linAuthor name used in this publication: 蒋捷Author name used in this publication: 赵仁亮2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Protecting digital legal professional privilege LPP data

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    The Best Paper AwardTo enable free communication between legal advisor and his client for proper functioning of the legal system, certain documents, known as Legal professional privilege (LPP) documents, can be excluded as evidence for prosecution. In physical world, protection of LPP information is well addressed and proper procedure for handling LPP articles has been established. However, there does not exist a forensically sound procedure for protecting 'digital' LPP information. In this paper, we try to address this important, but rarely addressed, issue. We point out the difficulties of handling digital LPP data and discuss the shortcomings of the current practices, then we propose a feasible procedure for solving this problem. © 2008 IEEE.published_or_final_versionThe 3rd International Workshop on Systematic Approaches to Digital Forensic Engineering (IEEE/SADFE 2008), Oakland, CA., 22 May 2008. In Proceedings of the 3rd SADFE, 2008, p. 91-10

    Maintaining hard disk integrity with digital legal professional privilege (LPP) data

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    Different mechanisms of cis-9,trans-11- and trans-10,cis-12- conjugated linoleic acid affecting lipid metabolism in 3T3-L1 cells

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    Conjugated linoleic acid (CLA) has been shown to reduce body fat mass in various experimental animals. It is valuable to identify its influence on enzymes involved in energy expenditure, apoptosis, fatty acid oxidation and lipolysis. We investigated isomer-specific effects of high dose, long treatment of CLA (75.4 Μmol/L, 8 days) on protein and gene expression of these enzymes in cultured 3T3-L1 cells. Proteomics identified significant up- or down-regulation of 52 proteins by either CLA isomer. Protein and gene expression of uncoupling protein (UCP) 1, UCP3, perilipin and peroxisome proliferator-activated receptor (PPAR) α increased whereas UCP2 reduced for both CLA isomers. And eight-day treatment of trans-10,. cis-12 CLA, but not cis-9,. trans-11 CLA, significantly up-regulated protein and mRNA levels of PKA (P<05), CPT-1 and TNF-α (P<01). Compared to protein expression, both isomers did not significantly influence the mRNA expression of HSL, ATGL, ACO and leptin. In conclusion, high-dose, long treatment of cis-9,. trans-11 CLA did not promote apoptosis, fatty acid oxidation and lipolysis in adipocytes, but may induce an increase in energy expenditure. trans-10,. cis-12 CLA exhibited greater influence on lipid metabolism, stimulated adipocyte energy expenditure, apoptosis and fatty acid oxidation, but its effect on lipolysis was not obvious. © 2010 Elsevier Inc.postprin
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