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1.
Summary.  Social science applications of sequence analysis have thus far involved the development of a typology on the basis of an analysis of one or two variables which have had a relatively low number of different states. There is a yet unexplored potential for sequence analysis to be applied to a greater number of variables and thereby a much larger state space. The development of a typology of employment experiences, for example, without reference to data on changes in housing, marital and family status is arguably inadequate. The paper demonstrates the use of sequence analysis in the examination of multivariable combinations of status as they change over time and shows that this method can provide insights that are difficult to achieve through other analytic methods. The data that are examined here provide support to intuitive understandings of clusters of common experiences which are both life course specific and related to socio-economic factors. Housing tenure is found to be of key importance in understanding the holistic trajectories that are examined. This suggests that life course trajectories are sharply differentiated by experience of social housing.  相似文献   
2.
美国大学本科教育研究   总被引:14,自引:0,他引:14  
本文分析了几所著名的美国大学本科教学的课程体系及教学计划 ,总结了其基本共性 ,同时分析了各大学的教学特色。通过对各大学电子工程类专业的教学计划进行剖析 ,给出了公共基础、专业基础、专业核心、专业选修课规定的课程及学分 ,并与我国的大学本科教学计划进行比较 ,提出了我国大学本科教育应改进的几个方面。  相似文献   
3.
Tactical production-distribution planning models have attracted a great deal of attention in the past decades. In these models, production and distribution decisions are considered simultaneously such that the combined plans are more advantageous than the plans resolved in a hierarchical planning process. We consider a two-stage production process, where in the first stage raw materials are transformed into continuous resources that feed the discrete production of end products in the second stage. Moreover, the setup times and costs of resources depend on the sequence in which they are processed in the first stage. The minimum scheduling unit is the product family which consists of products sharing common resources and manufacturing processes. Based on different mathematical modelling approaches to the production in the first stage, we develop a sequence-oriented formulation and a product-oriented formulation, and propose decomposition-based heuristics to solve this problem efficiently. By considering these dependencies arising in practical production processes, our model can be applied to various industrial cases, such as the beverage industry or the steel industry. Computation tests on instances from an industrial application are provided at the end of the paper.  相似文献   
4.
由于东西方文化的差异,对法治的理解和实践也不尽相同.在经济全球化的今天,中国一方面必须吸收和接受外来法治观念和法律制度,另一方面还要保持自身个性,以使法治发展适应自身的经济、政治和社会文化传统的要求.基于法治发展的这种两难状态,本文结合中国自身实际,引入了一种法治的新发展观--整合发展观,并在此基础上审视探析法治在中国实现的可能途径,从而提出在中国实现法治应当对法治要素进行位次排序.  相似文献   
5.
In this paper, we consider the problem of enumerating all maximal motifs in an input string for the class of repeated motifs with wild cards. A maximal motif is such a representative motif that is not properly contained in any larger motifs with the same location lists. Although the enumeration problem for maximal motifs with wild cards has been studied in Parida et al. (2001), Pisanti et al. (2003) and Pelfrêne et al. (2003), its output-polynomial time computability has been still open. The main result of this paper is a polynomial space polynomial delay algorithm for the maximal motif enumeration problem for the repeated motifs with wild cards. This algorithm enumerates all maximal motifs in an input string of length n in O(n 3) time per motif with O(n) space, in particular O(n 3) delay. The key of the algorithm is depth-first search on a tree-shaped search route over all maximal motifs based on a technique called prefix-preserving closure extension. We also show an exponential lower bound and a succinctness result on the number of maximal motifs, which indicate the limit of a straightforward approach. The results of the computational experiments show that our algorithm can be applicable to huge string data such as genome data in practice, and does not take large additional computational cost compared to usual frequent motif mining algorithms. This work is done during the Hiroki Arimura’s visit in LIRIS, University Claude-Bernard Lyon 1, France.  相似文献   
6.
江山 《东方论坛》2014,(6):34-43
在专记东晋中、晚期编年史的《续晋阳秋》中,檀道鸾将文学作为独立学科加以置评。他率先把"独尊"的儒学经典《诗经》与楚辞、前秦百家之言并列,提出了中国文学"体则《诗》《骚》,傍综百家"的"三元"论,并以此"三元"标准评论汉代"赋颂"、建安诗歌和西晋末年诗作。在评价两晋文学时,檀道鸾强调"庄、老"影响下产生的玄学及"玄胜之谈"对两晋道佛文学流变的重要影响。檀道鸾的文学流变史观,显现了南北分裂时期学思活跃、文人反思文化历史、重新界定文学源头的历史现实以及檀氏所历地域文化、家风传统、个人倾向互动等对其文史评论的影响。檀道鸾文学评论的自觉观点,是西晋虞挚的《文章流别论》,与南朝刘勰《文心雕龙》、钟嵘《诗品》等文学评论之间的重要环节。  相似文献   
7.
In sequential pattern analysis, the frequency of patterns is evaluated by the support. While computed efficiently from large databases, we show that the support cannot be compared between different databases, since it is influenced by the actual sequence length distribution. Models for this sequence length distribution are surveyed. One of these models, the Good distribution, appears to be sufficiently flexible for practice. It is used to exemplify an approach for adjusting the relative support such that the resulting adjusted support values are better comparable between different databases. We illustrate our findings with texts from the bilingual FinDe corpus.  相似文献   
8.
陈立双  祝丹 《统计研究》2020,37(4):18-31
大数据来源下CPI指数的创新编制,对及时了解新经济时代的物价走向和识别通胀危机、预测宏观经济拐点以实现我国通胀治理现代化、推动经济平稳和高质量发展具有重大意义。GEKS多边指数是近些年国际学术界重点研发的大数据热点价格指数,但其构造方法颇具争议。借助超市扫描大数据,就GEKS指数序列更新方法、窗口长度选择等学界难题开展理论与实证研究,获得了以下富有启发性的结论:①GEKS指数序列更新方法2、3应用效果相对较差;②随着窗口长度的增加,GEKS环比价格指数会趋于单位值,不同更新方法下的GEKS链式指数也会呈现一定的趋同性;而GEKS指数的通胀趋势判断力却不受此影响,但更新方法的选择却会导致其不同的通胀趋势预测结果;③更新方法4会随着窗口长度的增加而呈现更强的替代偏误,方法1却没有出现明显的替代偏误。综合而言,更新方法1和13个月窗口长度应该是编制GEKS指数序列更为合理的组合方式。  相似文献   
9.
We present a branch-and-bound (bb) algorithm for the multiple sequence alignment problem (MSA), one of the most important problems in computational biology. The upper bound at each bb node is based on a Lagrangian relaxation of an integer linear programming formulation for MSA. Dualizing certain inequalities, the Lagrangian subproblem becomes a pairwise alignment problem, which can be solved efficiently by a dynamic programming approach. Due to a reformulation w.r.t. additionally introduced variables prior to relaxation we improve the convergence rate dramatically while at the same time being able to solve the Lagrangian problem efficiently. Our experiments show that our implementation, although preliminary, outperforms all exact algorithms for the multiple sequence alignment problem. Furthermore, the quality of the alignments is among the best computed so far.  相似文献   
10.
In this paper we present a mathematical program and heuristic algorithms to schedule coils for the production operations in a copper (or steel) coil manufacturing industry. The processing facility uses continuous operations for processing (e.g., galvanizing and annealing) while the handling unit is a discrete coil. The ends of coils are “stitched” or welded together to enable continuous processing, and the joint is later sheared off to obtain the processed coils. Processing constraints impose restrictions on the compatibility between a pair of coils that are overcome by introducing a dummy coil called stringer, which is very expensive to a mill. This paper deals with modeling the sequencing/scheduling problem of coils on parallel non-identical machines to minimize stringer utilization. Both computational and practical experiences show the efficiency and effectiveness of the solution approaches. Implementing these methods in an actual coil annealing facility resulted in 65% reduction in stringer utilization.  相似文献   
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