A mathematical approach to the study of the United States Code

The United States Code (Code) is a document containing over 22 million words that represents a large and important source of Federal statutory law. Scholars and policy advocates often discuss the direction and magnitude of changes in various aspects of the Code. However, few have mathematically formalized the notions behind these discussions or directly measured the resulting representations. This paper addresses the current state of the literature in two ways. First, we formalize a representation of the United States Code as the union of a hierarchical network and a citation network over vertices containing the language of the Code. This representation reflects the fact that the Code is a hierarchically organized document containing language and explicit citations between provisions. Second, we use this formalization to measure aspects of the Code as codified in October 2008, November 2009, and March 2010. These measurements allow for a characterization of the actual changes in the Code over time. Our findings indicate that in the recent past, the Code has grown in its amount of structure, interdependence, and language.     

(6,3)-MDS Codes over an Alphabet of Size 4

An (n,k)_q-MDS code C over an alphabet (of size q) is a collection of q^k n–tuples over such that no two words of C agree in as many as k coordinate positions. It follows that n ≤ q+k−1. By elementary combinatorial means we show that every (6,3)₄-MDS code, linear or not, turns out to be a linear (6,3)₄-MDS code or else a code equivalent to a linear code with these parameters. It follows that every (5,3)₄-MDS code over must also be equivalent to linear.     

保障用户认证安全的判别最大熵语音识别机制

为了提高电子商务中用户认证的安全性,提出了一种高识别率的判别最大熵语音识别机制DME.该语音识别方法同时考虑语音与语言两方面的因素,并将语音和语言特征进行有效地结合,在统一的最大熵模型下,实现判别训练,确保观察样本能正确地分配到其对应状态,以提高所训练出的语音模型的正确识别率.详细的实验及与现有方法的比较结果表明,对不同环境下的语音数据,提出的语音识别方法具有更好的识别性能,对提高电子商务中用户认证系统的安全性能具有理论与实际意义.     

Authentication of cassia seeds on the basis of two-wavelength HPLC fingerprinting with the use of chemometrics

<正>High performance liquid chromatographic(HPLC) fingerprints of Cassia seed,a traditional Chinese medicine(TCM),were developed by means of the chromatograms at two wavelengths of 238 and 282 nm.Then,the two data sets were combined into one matrix.The application of principal component analysis(PCA) for this data matrix showed that the samples were clustered into four groups in accordance with the plant sources and preparation procedures.Furthermore,partial least squares(PLS),back propagation artificial neural network(BP-ANN),and radial basis function artificial neural network(RBF-ANN) were effectively applied to predict the category of the four different samples in the test set.     

数控机床加工语言的解释程序设计与实现

对数控机床加工程序语言─Ｇ代码采用编译原理的方法来实现解释执行，不但灵活性好，而且执行效率高。本文通过对一般形式Ｇ码用巴科斯范式表示法，归纳出其形式文法规则，并对其规则的词法分析和语法分析给出了实际算法框图。     

Tunable 2D time-wavelength optical CDMA encoder for differentiated service provisioning

We propose and demonstrate a reconfigurable tunable encoder for two-dimensional time-wavelength optical code division multiple access (OCDMA). This encoder is capable of creating 2D codes with variable code weight, enabling differentiated service provisioning. The demonstrated novel scheme uses ultra-fast optical delay lines and all-optical sampling while operating at 115 Gchip/s. Our proposed architecture provides an all-optical method of varying the code weight on a bit-per-bit basis, while maintaining the core architecture of a tunable OCDMA encoder.     

基于酉几何的等概的具有仲裁的认证码的构造

具有仲裁的认证码既要防止敌手的欺骗,又要防止收入和发方的互相欺骗,本文给出一种由酉几何构造等概的具有仲的认证码的方法,并计算了有关参数,分析了各种攻击成功的概率。