简评欧洲密码大计划的发展现状

NESSIE(New European Schemes for Signatures，Integrity，and Encryption)是一个为时三年的密码大计划，它的主要目的是为了推出一系列安全的密码模块，另一个目的是保持欧洲在密码研究领域的领先地位并增强密码在欧洲工业中的作用。它的整个运作过程是公开透明的，2000年3月公布了征集通告，2000年11月13～14日，召开第一次NESSIE会议，并公布征集到的所有算法。NESSIE共征集17个分组密码算法，经过一年多的评估，在今年9月12～13日召开的第二次NESSIE会议上，NESSIE公布了评选出的7个算法：IDEA，Khazad，MISTY1，SAFER++，Camellia，RC6，SHACAL，它们将作为NESSIE计划下一阶段重点评估的对象。NEESIE预计将在明年秋季召开第三次会议，届时将宣布最后的评选结果。本文简要介绍NESSIE的评估原则，阐述NESSIE对各个候选算法的取舍原因，同时列出算法设计者和公众对各个算法的分析情况。

Designing Of Partial Similarity Models And Evaluation Method In Polymer Flooding Experiment

Based on the scaling criteria of polymer flooding reservoir obtained in our previous work in which the gravity and capillary forces, compressibility, non-Newtonian behavior, absorption, dispersion, and diffusion are considered, eight partial similarity models are designed. A new numerical approach of sensitivity analysis is suggested to quantify the dominance degree of relaxed dimensionless parameters for partial similarity model. The sensitivity factor quantifying the dominance degree of relaxed dimensionless parameter is defined. By solving the dimensionless governing equations including all dimensionless parameters, the sensitivity factor of each relaxed dimensionless parameter is calculated for each partial similarity model; thus, the dominance degree of the relaxed one is quantitatively determined. Based on the sensitivity analysis, the effect coefficient of partial similarity model is defined as the summation of product of sensitivity factor of relaxed dimensionless parameter and its relative relaxation quantity. The effect coefficient is used as a criterion to evaluate each partial similarity model. Then the partial similarity model with the smallest effect coefficient can be singled out to approximate to the prototype. Results show that the precision of partial similarity model is not only determined by the number of satisfied dimensionless parameters but also the relative relaxation quantity of the relaxed ones.

Slope Stability Analysis Using Anisotropic and Nonlinear Failure Criteria

The shear strength of soils or rocks developed in a landslide usually exhibits anisotropic and nonlinear behavior. The process of sedimentation and subsequent consolidation can cause anisotropy of sedimentary soils or rocks, for instance. Nonlinearity of failure envelope could be attributed to "interlocking" or "dilatancy" of the material, which is generally dependent upon the stress level. An analytical method considering both anisotropy and nonlinearity of the failure envelops of soil and rocks is presented in the paper. The nonlinearfailure envelopes can be determined from routine triaxial tests. A spreadsheet program, which uses the Janbu's Generalized Procedure of Slice and incorporates anisotropic, illustrates the implementation of the approach and nonlinearfailure envelops. In the analysis, an equivalent Mohr-Coulomb linear failure criterion is obtained by drawing a tangent to the nonlinear envelope of an anisotropic soil at an appropriate stress level. An illustrative example is presented to show the feasibility and numerical efficiency of the method.

EVALUATION OF THE RELIABILITY OF KALMAN FILTERING RESULTS IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

This paper deals with the evaluation of the reliability of the analytical results obtained by Kalman filtering. Two criteria for evaluation were compared: one is based on the autocorrelation analysis of the innovation sequence, the so-called NAC criterion; the other is the innovations number, which actually is the autocorrelation coefficient of the innovation sequence at the initial wavelength. Both criteria allow compensation for the wavelength positioning errors in spectral scans, but there exists a difference in the way they work. The NAC criterion can provide information about the reliability of an individual result, which is very useful for the indication of unmodelled emissions, while the innovations number should be incorporated with the normalization of the innovations or seek the help of the sequence itself for the same purpose. The major limitation of the NAC criterion is that it does not allow the theoretical modelling of continuous backgrounds, which, however, is convenient in practical analysis and can be taken with the innovations number criterion.