A multiple stream generator based on de Bruijn digraph homomorphisms

We propose a method to obtain several streams of pseudorandom numbers based on a backbone generator of the generalized shift register type. The method is based on inverting one cycle in a de Bruijn digraph into many sequences in a higher-order de Bruijn graph via an appropriate graph homomorphism. We apply this technique to twisted generalized feedback shift register generators and to the Mersenne Twister MT19937. Positive results of statistical testing are reported.     

An Approximation Algorithm for Alignment of Multiple Sequences using Motif Discovery

Given a set of N sequence, the Multiple Sequence Alignment problem is to align these N sequences, possibly with gaps, that brings out the best commonality of the N sequences. The quality of the alignment is usually measured by penalizing the mis-matches and gaps, and rewarding the matches with appropriate weight functions. However for larger values of N, additional constraints are required to give meaningful alignments. We identify a user-controlled parameter, an alignment number K (2 K N): this additional requirement constrains the alignment to have at least K sequences agree on a character, whenever possible, in the alignment. We identify a natural optimization problem for this approach called the K-MSA problem. We show that the problem is MAX SNP hard. We give a natural extension of this problem that incorporates biological relevance by using motifs (common patterns in the sequences) and give an approximation algorithm for this problem in terms of the motifs in the data. MUSCA is an implementation of this approach and our experimental results indicate that this approach is efficient, particularly on large numbers of long sequences, and gives good alignments when tested on biological data such as DNA and protein sequences.     

The Bahadur representation for sample quantiles under strongly mixing sequence

Sun [2006, The Bahadur representation for sample quantiles under weak dependence. Statist. Probab. Lett. 76, 1238-1244] established the Bahadur representation for sample quantiles under the strongly mixing sequence. But there are some problems in the proofs of the main results. In the paper, we further investigate the Bahadur representation for sample quantiles under strongly mixing sequence and get better bound than that in Sun (2006).     

资源受限下平行工序顺序对优化的0-1规划模型

资源受限是工程项目时刻都可能面对的挑战。由于资源限制,需要将原项目计划中相互之间无优先关系的平行工序调整为顺序工序。平行工序顺序化可导致项目工期延迟,因此需考虑如何使项目工期延迟最小。该平行工序顺序优化问题是项目调度问题,也是排列组合问题,通常难度很大,包括一些NP-hard问题。本文主要研究该问题的一类典型子问题——平行工序顺序对优化,即如何将项目中某2n个平行工序调整为n个顺序工序对,并且对项目工期的影响最小。该问题的总方案数可达到（2n）!/n!。本文借助工序网络（如CPM网络）,运用简单的时间参数量化了平行工序顺序化对项目工期的影响,进而降低问题的求解难度,建立了纯0-1规划模型。实验验证了该模型的求解效率,求解100个平行工序规模的问题平均耗时0.2605秒,而求解500个平行工序规模的问题平均耗时10.66秒。     

The social stratification of time use patterns

Time use is both a cause of social inequality and a consequence of social inequality. However, how social class stratifies time use patterns is seldom studied. In this paper, I describe the time use patterns in the years 1983 and 2015 by social class, and gender in the British context. Using sequence analysis methods, I show how the diversity of time use patterns in British society is socially stratified. I find that 13 clusters capture the heterogeneity of time use patterns and that these clusters are associated with social class, gender, and day of the week. These clusters capture patterns of paid and unpaid work schedules, as well as leisure patterns. The results show that men have experienced a reduction of the standard Monday to Friday 8-hr working day, while women have experienced a general increase in this type of schedule. On the other hand, patterns of domestic working days have reduced for women and increased for men. Important differences exist in paid and unpaid work patterns between social classes. Working-class women have experienced an important increase in shift work on weekends. They are also much more likely to be doing unpaid work on weekdays compared to upper-class and middle-class women. Working-class men are more likely to experience non-working days and leisure days on both weekdays and weekends and are more likely to be doing shift work. They are also more often doing unpaid work on weekdays compared to men in upper-class households. Patterns of childcare indicate that all families have increased their childcare time. Men in upper-class households in particular have experienced an important growth in childcare time between 1983 and 2015. I conclude by discussing how time use can further our understanding of social stratification.     

The sequence analysis of hospitals that established social work department under fuzzy environment

This paper reviews the existing literature on hospital social work and discusses intervention strategies for improving social work practice in hospital. The objective of this study was to improve the quality of medical care. But few studies have compared social work services between different hospitals. This study describes qualitative analysis under fuzzy environment, extracts the main influencing factors and establishes a comprehensive evaluation index system. It provides comprehensive evaluation for alternative hospitals by the fuzzy clustering method. This paper proposes a new mixed fuzzy clustering algorithm on the basis of analysing the axiomatic fuzzy set (AFS) and K-means algorithm, which is not affected by some complicated parameter issues and has higher statistical validity. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is applied for selecting the best option for each cluster and a comparative analysis is done. Results from a case study in Shanghai, China, confirm that the proposed approach is effective by using information entropy to test. By comparing AFS, K-means and C-means algorithms, the hybrid algorithm can find the two closest attributes of evaluation index of hospital social work, and the proposed approach can be easily help raise the level of hospital social work service.     

“江湖”:中国文化的另一个视窗——兼论“差序格局”的社会结构内涵

江湖是熟人社会以外混沌、非透明、乏规则的互动空间。在这种互动空间里,形成了历时性的江湖传统。它在组织模式上体现为模拟血缘关系的异姓结拜和结盟拜会,在价值模式上体现为等差有序、内外有别的义气。江湖传统表面上看主要存在于下层群体当中,实际上深嵌于常态文化体系之内。江湖作为一个独特的视窗,在中西学者熟悉的儒教中国、帝制中国、乡土中国等局部意象之外,提供了一个关于传统中国的整合性框架,即江湖中国。由此,传统中国社会结构的立体特征能够得到完整呈现。基层的乡土社区层面,呈现为费孝通所说的差序格局特征,顶端的庙堂层面同样如此。而介于乡土社区与庙堂之间的混沌江湖,仍旧要援引熟人世界的结构模型,同样讲究差序之别。这种一般社会层面的事实证据表明,差序格局概念确实具有立体社会结构内涵。     

数学实验及其应用

本文借助计算机解决了一些目前还没有被解决的数学问题。     

深水区域开展蛙泳技术教学方法的探讨

结合运动技术理论,研究探讨如何在短期内,就深水区域开展蛙泳技术的教学方法和途径,使蛙泳技术教学尽快取得较好的教学效果.     

Lucas公钥密码体制及其安全性

Ｌｕｃａｓ 公钥密码体制是数论中的Ｌｕｃａｓ 序列与公钥密码体制思想的有效结合。在此基础上,讨论了该体制的安全性问题。通过对几种破译该体制的攻击途径的分析,证明了Ｌｕｃａｓ 体制是一种建立在两种密码假设基础之上的公钥密码体制,从而保证了很高的有效性和安全性