Mean square consensus of double-integrator multi-agent systems under intermittent control: A stochastic time scale approach     

Dylan Poulsen  Michael Defoort  Mohamed Djemai 《Journal of The Franklin Institute》2019,356(16):9076-9094

We consider the leader–follower consensus problem for a multi-agent system where information is exchanged only on a non-uniform discrete stochastic time domain. For a second-order multi-agent system subject to intermittent information exchange, we model the tracking error dynamics as a $\mu ?$varying linear system on a discrete stochastic time scale, where μ is the graininess operator. Based on a Lyapunov operator and a positive perturbation operator on the space of symmetric matrices, we derive necessary and sufficient conditions to design a decentralized consensus protocol. This protocol allows us to cast the mean-square exponential consensus problem within the framework of dynamic equations on stochastic time scales. We establish some theoretical results which allow for the computation of the control gain matrix which guarantees the mean-square exponential stability with a given decay rate for the error dynamics. To show the effectiveness of the theoretical results, some simulation and experimental results on multi-robot systems have been performed.  相似文献   

Design of a fast real-time LPV model predictive control system for semi-active suspension control of a full vehicle     

Marcelo Menezes Morato  Manh Quan Nguyen  Olivier Sename  Luc Dugard 《Journal of The Franklin Institute》2019,356(3):1196-1224

This article is concerned with the control of a Semi-Active suspension system of a 7DOF Full Vehicle model, equipped with four Electro Rheological (ER) dampers, taking into account their incipient dissipativity constraints. Herein, a real-time, fast, advanced control structure is presented within the Model Predictive Control framework for Linear Parameter Varying (LPV) systems. The control algorithm is developed to provide a suitable trade-off between comfort and handling performances of the vehicle in a very limited sampling period ($T_s=5\text{ms}$), in view of a possible realtime implementation on a real vehicle. The control structure is tested and compared to other standard fast control approaches. Full nonlinear realistic simulation results illustrate the overall good operation and behaviour of the proposed control approach.  相似文献   

Stability analysis and control design based on average dwell time approaches for switched nonlinear port-controlled Hamiltonian systems     

Zi-Ming Wang  Airong Wei  Xianfu Zhang 《Journal of The Franklin Institute》2019,356(6):3368-3397

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大学生英语演讲中的隐含作者分析     

黄滔 《四川教育学院学报》2011,(10):92-95

对学生演讲稿的写作过程及成稿文本研究和分析表明,学生演讲中存在清晰的隐含作者。由于演讲是一种公共传播行为,学生演讲中的隐含作者与媒体叙事中的隐含作者较为相似,表现为更优秀、更强大的“第二自我”和文本所体现的、同时也是环境和社会意识形态所要求的价值观和道德观这两个层次。真实作者（学生）与隐含作者的互动、互融过程,就是学生进步、提高的过程。在演讲教学中正确运用隐含作者的作用,将对学生成长产生深远的积极作用。  相似文献   

用特色栏目打造高校学报的鲜明个性——以《西安科技大学学报》为例     

李克永 《编辑学报》2019,31(2):220-222

通过分析和研究《西安科技大学学报》创办特色栏目的条件及实践,探讨用特色栏目凸显高校学报的鲜明特征。研究认为:学科优势是特色栏目发展的决定性条件,专家优势是特色栏目发展的核心,稳定的作者群是特色栏目发展的必备条件。同时,高校学报依靠高校的学术优势和区位优势,确立特色栏目、吸纳优质稿件、吸引校外优质作者群,用特色栏目打造期刊的鲜明个性。高校学报特色栏目的发展模式,不仅可以为同类学报的特色发展提供经验,还可以为不同类型的学术期刊提供借鉴。  相似文献   

Measuring scientific contributions with modified fractional counting     

Gunnar Sivertsen  Ronald Rousseau  Lin Zhang 《Journal of Informetrics》2019,13(2):679-694

We develop and propose a new counting method at the aggregate level for contributions to scientific publications called modified fractional counting (MFC). We show that, compared to traditional complete-normalized fractional counting, it eliminates the extreme differences in contributions over time that otherwise occur between scientists that mainly publish alone or in small groups and those that publish with large groups of co-authors. As an extra benefit we find that scientists in different areas of research turn out to have comparable average contributions to scientific articles. We test the method on scientists at Norway’s largest universities and find that, at an aggregate level, it indeed supports comparability across different co-authorship practices as well as between areas of research. MFC is thereby useful whenever the research output from institutions with different research profiles are compared, as e.g., in the Leiden Ranking. Finally, as MFC is actually a family of indicators, depending on a sensitivity parameter, it can be adapted to the circumstances.  相似文献   

Ranking scientific articles based on bibliometric networks with a weighting scheme     

Yu Zhang  Min Wang  Florian Gottwalt  Morteza Saberi  Elizabeth Chang 《Journal of Informetrics》2019,13(2):616-634

As the volume of scientific articles has grown rapidly over the last decades, evaluating their impact becomes critical for tracing valuable and significant research output. Many studies have proposed various ranking methods to estimate the prestige of academic papers using bibliometric methods. However, the weight of the links in bibliometric networks has been rarely considered for article ranking in existing literature. Such incomplete investigation in bibliometric methods could lead to biased ranking results. Therefore, a novel scientific article ranking algorithm, W-Rank, is introduced in this study proposing a weighting scheme. The scheme assigns weight to the links of citation network and authorship network by measuring citation relevance and author contribution. Combining the weighted bibliometric networks and a propagation algorithm, W-Rank is able to obtain article ranking results that are more reasonable than existing PageRank-based methods. Experiments are conducted on both arXiv hep-th and Microsoft Academic Graph datasets to verify the W-Rank and compare it with three renowned article ranking algorithms. Experimental results prove that the proposed weighting scheme assists the W-Rank in obtaining ranking results of higher accuracy and, in certain perspectives, outperforming the other algorithms.  相似文献   

Authorship analysis of specialized vs diversified research output     

Giovanni Abramo  Ciriaco Andrea D’Angelo  Flavia Di Costa 《Journal of Informetrics》2019,13(2):564-573

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   

How does collaboration affect researchers’ positions in co-authorship networks?     

Xiangjie Kong  Mengyi Mao  Huizhen Jiang  Shuo Yu  Liangtian Wan 《Journal of Informetrics》2019,13(3):887-900

Collaboration usually has a positive effect on researchers’ productivity: researchers have become increasingly collaborative, according to recent studies. Numerous studies have focused on enhancing research collaboration by recommendation technology and measuring the influence of researchers. However, few studies have investigated the effect of collaboration on the position of a researcher in the research social network. In this paper, we explore the relationships between collaboration and influence by social analytical methods, which are pertinent to analyzing the network structure and individual traits. We evaluate three aspects of the researchers’ influence: friendship paradox validation, social circle, and structure of a researcher's ego network. Furthermore, the ”six degrees of Bacon number” theory, generalized friendship paradox, and triadic closure theory are introduced to support our analysis. Experimental results show that collaboration can help researchers increase their influence to some extent.  相似文献   

Can Google Scholar and Mendeley help to assess the scholarly impacts of dissertations?     

Kayvan Kousha  Mike Thelwall 《Journal of Informetrics》2019,13(2):467-484

Dissertations can be the single most important scholarly outputs of junior researchers. Whilst sets of journal articles are often evaluated with the help of citation counts from the Web of Science or Scopus, these do not index dissertations and so their impact is hard to assess. In response, this article introduces a new multistage method to extract Google Scholar citation counts for large collections of dissertations from repositories indexed by Google. The method was used to extract Google Scholar citation counts for 77,884 American doctoral dissertations from 2013 to 2017 via ProQuest, with a precision of over 95%. Some ProQuest dissertations that were dual indexed with other repositories could not be retrieved with ProQuest-specific searches but could be found with Google Scholar searches of the other repositories. The Google Scholar citation counts were then compared with Mendeley reader counts, a known source of scholarly-like impact data. A fifth of the dissertations had at least one citation recorded in Google Scholar and slightly fewer had at least one Mendeley reader. Based on numerical comparisons, the Mendeley reader counts seem to be more useful for impact assessment purposes for dissertations that are less than two years old, whilst Google Scholar citations are more useful for older dissertations, especially in social sciences, arts and humanities. Google Scholar citation counts may reflect a more scholarly type of impact than that of Mendeley reader counts because dissertations attract a substantial minority of their citations from other dissertations. In summary, the new method now makes it possible for research funders, institutions and others to systematically evaluate the impact of dissertations, although additional Google Scholar queries for other online repositories are needed to ensure comprehensive coverage.  相似文献