排序方式： 共有21条查询结果，搜索用时 15 毫秒
1.
In this paper we study the scaling behavior of nucleotide cluster in 11 chromosomes of Encephalitozoon cuniculi Genome. The statistical distribution of nucleotide clusters for 11 chromosomes is characterized by the scaling behavior of P（S） ∝ e^-αs＇ where S represents nucleotide cluster size. The cluster-size distribution P（S1＋S2） with the total size of sequential C-G cluster and A-T cluster S1＋S2 were also studied. P（S1＋S2） follows exponential decay. There does not exist the case of large C-G cluster following large A-T cluster or large A-T cluster following large C-G cluster. We also discuss the relatively random walk length function L（n） and the local compositional complexity of nucleotide sequences based on a new model. These investigations may provide some insight into nucleotide cluster of DNA sequence. 相似文献
2.
模糊PID控制的遗传算法优化 总被引：1，自引：0，他引：1
訾兴建 《淮北职业技术学院学报》2007,6(5):53-55
模糊控制中的模糊推理规则和隶属函数的选取往往依据专家或技术人员的经验,具有较大的人为主观性,尤其在较强的非线性系统和未知动态环境条件下,其控制性能往往达不到客观要求。本文采用改进的遗传算法优化模糊控制中的比例因子,从而对控制规则和隶属函数进行优化。仿真结果表明,经过优化后的模糊控制器控制规则和隶属函数更加客观合理,控制系统的动、静态性能都有较大提高。 相似文献
3.
2000-2011年WOS科学学期刊关键词分析——以共词和SNA为方法 总被引：1，自引：0，他引：1
科学学自上世纪20年代兴起以来,随着新兴研究方法的应用与新兴研究内容的注入,日益发展。以WOS中的科学学研究类期刊的关键词为分析对象,采用文献计量学方法、社会网络方法及统计学方法进行研究,分别从关键词词频、共现关系以及多维尺度分析方法来探索WOS科学学期刊在2000-2011年间的研究重点、相关研究领域以及聚类态势。从研究体系分层来看,科学学研究仍集中于应用研究层面;从研究内容来看,分别寻找到的热点研究领域和重要研究领域代表了当今科学学的主流研究方向。应用类的科学学研究无疑是当今科学学研究的主流,但理论、方法类的研究也并没有销声匿迹。 相似文献
4.
本文通过对无机含氧酸盐溶解过程的分析,提出了判断无机含氧酸盐溶解性的依据,推导了无机含氧酸盐溶解性计算公式. 相似文献
5.
J. Roschelle D. Tatar N. Shechtman J. Knudsen 《Educational Studies in Mathematics》2008,68(2):149-170
One of the great strengths of Jim Kaput’s research program was his relentless drive towards scaling up his innovative approach to teaching the mathematics of change and variation. The SimCalc mission, “democratizing access to the mathematics of change,” was enacted by deliberate efforts to reach an increasing number of teachers and students each year. Further, Kaput asked: What can we learn from research at the next level of scale (e.g., beyond a few classrooms at a time) that we cannot learn from other sources? In this article, we develop an argument that scaling up research can contribute important new knowledge by focusing researchers’ attention on the robustness of an innovation when used by varied students, teachers, classrooms, schools, and regions. The concept of robustness requires additional discipline both in the design process and in the conduct of valid research. By examining a progression of three studies in the Scaling Up SimCalc program, we articulate how scaling up research can contribute to designing for and evaluating robustness. 相似文献
6.
用多分辨分析构造正交小波基的方法 总被引：1，自引：0，他引：1
本文介绍了利用多分辨分析构造正交小波基的方法和步骤。 相似文献
7.
In this study, we analysed running world records and found that the mean speed of the race, μ, as a function of the record time, τ, can be described asymptotically by two well-defined scaling laws of the form u ?s τ - β. There is a break in the scaling laws (?1000m) between the shorter and the longer races at a characteristic time of around 150-170 s, after which a new scaling regime emerges. This is the first occasion that this characteristic time has been clearly found in physical terms; we interpreted it as the transition time between the anaerobic and the aerobic energy expenditure of athletes. This phenomenon is independent of the athletes' sex and is also found in swimming races with similar values of the characteristic time. We also investigated the forecasting of world records using historical data. Using an approach based on the identification of non-Poissonian events for a sequence of temporal point processes, we found that the sequence of improvements in all athletic records from 1900 to the present day cannot be considered as a sequence of completely random events. 相似文献
8.
阅读理解能力测验中所选择的文章在内容方面对不同专业背景的考生亚团体是否具有公平性的问题,是测验效度高低的重要证据,也是测验效度验证（validation）的重要环节。本研究以中国语言与文学专业考生为目标组,分别将经济学专业和生物医学专业考生作为参照组,采用效标测量和蕴涵量表分析相结合的方法,对HSK（高等）阅读理解测验的文章难度对三个不同专业背景的考生组的公平性问题进行了检验。研究结果表明,两个参照组考生尽管具有各自的相对专业优势,但他们在六篇阅读材料上获得的难度排列顺序与目标组考生完全一致;虽然目标组考生不具备汉语知识以外的其他专业优势,但因为HSK考试所选择的阅读材料没有涉及语言知识本身以外的特殊专业要求,因而测验对三个不同专业背景的考生具有较高的公平性。 相似文献
9.
Rosana P. Mula 《The Journal of Agricultural Education and Extension》2013,19(2):153-168
Abstract The process of innovation-development to scaling is varied and complex. Various actors are involved in every stage of the process. In scaling the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)-led integrated watershed management projects in India and South Asia, three drivers were identified—islanding approach, multi-layered partnership, and innovative means of knowledge sharing. Through a consortium mode of partnership, ICRISAT established ‘islands’ or models for showcasing soil and water conservation interventions and integrated these with other concerns of the farming system (crops and livestock) and socio-economic dimension (capacity building). Activities on the islands were planned and implemented by the locals and replicated in satellite watersheds. Partnerships forged through the consortium approach provided a dearth of resources such as social capital. Projects built on trust and good relationships can be sustained even when direct financial support ceases. Innovative means of knowledge sharing like the Virtual Academy for the Semi-Arid Tropics (VASAT)—ICRISAT's innovation in capacity building and information management—provided the link between rural farm households and researchers. Credible intermediaries and markets were linked to farmers by information communication technology channels and markets through an interface of information and open/distance learning methods. VASAT's multi-dimensional strategy has been an important resource for a south–south partnership. 相似文献
10.
Richard O. Mason 《The Information Society》2013,29(3):229-239
Abstract The worldwide use of computers, telecommunications, and other information technologies is giving rise to the formation of new communities called “information communities.” In the United States, for example, more people are employed as information givers, takers, or orchestrators in these communities than in any other occupation class. With so many social resources going into the conduct of these communities, it is essential that they are designed to be ethical. This requires that we identify the parties involved in each community, that we be empathetic and sympathetic to their needs and that we follow Kant's dictum by always treating them as “ends in themselves.” 相似文献