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91.
92.
The present work investigates the relations between amplitude and type of collaboration (intramural, extramural domestic or international) and output of specialized versus diversified research. By specialized or diversified research, we mean within or beyond the author’s dominant research topic. The field of observation is the scientific production over five years from about 23,500 academics. The analyses are conducted at the aggregate and disciplinary level. The results lead to the conclusion that in general, the output of diversified research is no more frequently the fruit of collaboration than is specialized research. At the level of the particular collaboration types, international collaborations weakly underlie the specialized kind of research output; on the contrary, extramural domestic and intramural collaborations are weakly associated with diversified research. While the weakness of association remains, exceptions are observed at the level of the individual disciplines. 相似文献
93.
Robert B. Anderson Julius A. Marshall Andrea L’Afflitto 《Journal of The Franklin Institute》2021,358(12):6281-6308
In classical model reference adaptive control (MRAC), the adaptive rates must be tuned to meet multiple competing objectives. Large adaptive rates guarantee rapid convergence of the trajectory tracking error to zero. However, large adaptive rates may also induce saturation of the actuators and excessive overshoots of the closed-loop system’s trajectory tracking error. Conversely, low adaptive rates may produce unsatisfactory trajectory tracking performances. To overcome these limitations, in the classical MRAC framework, the adaptive rates must be tuned through an iterative process. Alternative approaches require to modify the plant’s reference model or the reference command input. This paper presents the first MRAC laws for nonlinear dynamical systems affected by matched and parametric uncertainties that constrain both the closed-loop system’s trajectory tracking error and the control input at all times within user-defined bounds, and enforce a user-defined rate of convergence on the trajectory tracking error. By applying the proposed MRAC laws, the adaptive rates can be set arbitrarily large and both the plant’s reference model and the reference command input can be chosen arbitrarily. The user-defined rate of convergence of the closed-loop plant’s trajectory is enforced by introducing a user-defined auxiliary reference model, which converges to the trajectory tracking error obtained by applying the classical MRAC laws before its transient dynamics has decayed, and steering the trajectory tracking error to the auxiliary reference model at a rate of convergence that is higher than the rate of convergence of the plant’s reference model. The ability of the proposed MRAC laws to prescribe the performance of the closed-loop system’s trajectory tracking error and control input is guaranteed by barrier Lyapunov functions. Numerical simulations illustrate both the applicability of our theoretical results and their effectiveness compared to other techniques such as prescribed performance control, which allows to constrain both the rate of convergence and the maximum overshoot on the trajectory tracking error of uncertain systems. 相似文献
94.
Zi Yue’er 《中外文化交流(英文版)》2011,(8):4-9
During Chinese Vice Premier Li Keqiang’s official visit to Australia in October 2009, Chinese and Australian leaderships reached a consensus of hosting cultural years in each other’s country. From June 2010 to June 2011, "Experience Australia"—the Year of Australian Culture was successfully held in China. From June 2011 to June 2012, "Experience China"—the Year of Chinese Culture (YCCiA) is celebrated in Australia, featuring nearly 100 cultural events ranging from performing arts projects to visual art exhibitions to film festivals. 相似文献
95.
Zi Yue’er 《中外文化交流(英文版)》2011,(11):4-7
Public cultural ser vice has gained increasing attention worldwide in recent years. It has become ever y government’s top priority to build a well-developed public cultural service system, provide diverse cultural products and promote cultural consumption by the public. In one-day disccusions of the Cultural Session, participants shared each other’s experience in public cultural service, in particular, concepts and practices of Xi’an City. Participants reached a consensus of increasing exchanges and cooperation in the sector of public culture in the future. 相似文献
96.
97.
[目的/意义] 针对"和+共享图书馆"的建设现状进行分析,反映长沙市民间自办公共阅读空间的一般性问题,为长沙市民间自办公共阅读空间可持续发展提出优化建议。[方法/过程] 通过现场观察、问卷调查、访谈法等方法对"和+共享图书馆"建设现状和特点进行剖析,认为存在专业人员短缺、空间利用率偏低、营销形式单一等问题。[结果/结论] 提出优化建议包括:构建运营管理机制;加强专业人员培养;增强公共阅读空间服务的可及性和丰富服务营销形式等,以促进长沙市民办公共阅读空间的良性发展。 相似文献
98.
GAO Hongli YANG Lei XU Sheng LONG Zhou LIU Kai HU Xiang’en 《Frontiers of Education in China》2022,17(1):100
Discussion is a common and important learning process. Involvement of a virtual agent can provide adaptive support for the discussion process. Argumentative knowledge construction is beneficial to learners’ acquisition of knowledge,but the effectiveness of argumentative scaffolding in existing studies is not consistent. Based on an intelligent discussion system, a total of 47 undergraduate students took part in the experiment and they were assigned to three different conditions: content-related plus content-independent scaffolding condition, content-related scaffolding condition, and the control condition. Under the content-related and content-independent scaffolding condition, the computer agent provided an idea from semantically different categories (content-related scaffolding) according to the automatic categorization of the current contributions, and further inquired the participants about their attitudes and reasons (content-independent scaffolding). Under the condition of content-related scaffolding condition, the virtual agent only provided semantically different viewpoints. Under the control condition, the subjects expressed their opinion independently without the participation of the virtual agent. Findings revealed that compared with the control group, when the virtual agent provided semantically different ideas (content-related scaffolding), the discussion breadth (number of categories) was improved and the subjects felt that they had a more comprehensive understanding of the problem. Compared with the content-related scaffolding condition, when the virtual agent provided semantically different ideas and further asked about the attitudes and reasons, the subjects expressed more agreement with these views, but mentioned fewer categories during the discussion. This study suggests that the content-related scaffolding can facilitate the cognitive processing effect relevant to the topic of discussion. When the content independent scaffolding is added, it can promote the argumentative processing, but may have a negative effect on the cognitive processing related to the topic discussed. 相似文献
99.
The growing complexity of scientific challenges demands increasingly intense research collaboration, both domestic and international. The resulting trend affects not only the modes of producing new knowledge, but also the way it is disseminated within scientific communities. This paper analyses the relationship between the “degree of internationalization” of a country’s scientific production and that of the relevant citing publications. The empirical analysis is based on 2010-2012 Italian publications. Findings show: i) the probability of being cited increases with the degree of internationalization of the research team; ii) totally domestic research teams tend to cite to a greater extent totally domestic publications; iii) vice versa, publications resulting from international collaborations tend to be more cited by totally foreign publications rather than by publications including domestic authors. These results emerge both at overall and at discipline level. Findings might inform research policies geared towards internationalization. 相似文献
100.
Tenaha O’Reilly Jonathan Weeks John Sabatini Laura Halderman Jonathan Steinberg 《Educational Psychology Review》2014,26(3):403-424
When designing a reading intervention, researchers and educators face a number of challenges related to the focus, intensity, and duration of the intervention. In this paper, we argue there is another fundamental challenge—the nature of the reading outcome measures used to evaluate the intervention. Many interventions fail to demonstrate significant improvements on standardized measures of reading comprehension. Although there are a number of reasons to explain this phenomenon, an important one to consider is misalignment between the nature of the outcome assessment and the targets of the intervention. In this study, we present data on three theoretically driven summative reading assessments that were developed in consultation with a research and evaluation team conducting an intervention study. The reading intervention, Reading Apprenticeship, involved instructing teachers to use disciplinary strategies in three domains: literature, history, and science. Factor analyses and other psychometric analyses on data from over 12,000 high school students revealed the assessments had adequate reliability, moderate correlations with state reading test scores and measures of background knowledge, a large general reading factor, and some preliminary evidence for separate, smaller factors specific to each form. In this paper, we describe the empirical work that motivated the assessments, the aims of the intervention, and the process used to develop the new assessments. Implications for intervention and assessment are discussed. 相似文献