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[目的/意义] 探索突发公共卫生事件中农村中老年人向正在接受高等教育的子辈寻求事件相关信息的代际反哺行为及其形成过程,以期为农村地区的风险信息的传播构建新路径,同时亦为政府部门进行乡村治理提供可实践的思路。[方法/过程] 基于动机信息管理理论,重点关注突发公共卫生事件中农村中老年人的不确定性差异、焦虑、结果预期和效能是否会影响他们的信息寻求行为。同时,在获得相关信息后,他们是否会表现出信息采纳和信息传递的行为。在新冠肺炎疫情发生期间,利用问卷调查法收集数据,通过统计分析软件进行研究假设的验证。[结果/结论] 通过分析发现,不确定性差异会引起农村中老年人的焦虑,进而影响其结果预期和效能,最后触发他们的信息寻求行为。他们亦会采纳和传递所获取的信息,以达到共同防疫的目的。  相似文献   
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For a class of large-scale nonlinear time-delay systems with uncertain output equations, the problem of global state asymptotic regulation is addressed by output feedback. The class of systems under consideration are subject to feedforward growth conditions with unknown growth rate and time delays in inputs and outputs. To deal with the system uncertainties and the unknown delays, a novel low-gain observer with adaptive gain is firstly proposed; next, an adaptive output feedback delay-free controller is constructed by combining Lyapunov-Krasovskii functional with backstepping algorithm. Compared with the existing results, the controllers proposed are capable of handling both the uncertain output functions and the unknown time delays in inputs and outputs. With the help of dynamic scaling technique, it is shown that the closed-loop states converge asymptotically to zero, while the adaptive gain is bounded globally. Finally, the effectiveness of our control schemes are illustrated by three examples.  相似文献   
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《Journal of Informetrics》2019,13(3):830-840
This study inserts in the stream of research on the perverse effects that PBRF systems can induce in the subjects evaluated. The authors’ opinion is that more often than not, it is the doubtful scientific basis of the evaluation criteria that leave room for opportunistic behaviors. The work examines the 2004–2010 Italian national research assessment (VQR) to test the lack of possible opportunistic behavior by universities in order to limit the penalization of their performance (and funding) due to the presence of scientifically unproductive professors in faculty. In particular, institutions may have favored “gift authorship” practices. The analysis thus focuses on the output of professors who were unproductive in the VQR publication window, but became productive (“new productives”) in the following five years. A number of universities show a higher than average share of publications by new productives that are in co-authorship exclusively with colleagues from the same university. Although this might be thought to reflect opportunistic behavior by universities, the empirical evidence does not support this assumption.  相似文献   
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《Journal of Informetrics》2019,13(2):485-499
With the growing number of published scientific papers world-wide, the need to evaluation and quality assessment methods for research papers is increasing. Scientific fields such as scientometrics, informetrics, and bibliometrics establish quantified analysis methods and measurements for evaluating scientific papers. In this area, an important problem is to predict the future influence of a published paper. Particularly, early discrimination between influential papers and insignificant papers may find important applications. In this regard, one of the most important metrics is the number of citations to the paper, since this metric is widely utilized in the evaluation of scientific publications and moreover, it serves as the basis for many other metrics such as h-index. In this paper, we propose a novel method for predicting long-term citations of a paper based on the number of its citations in the first few years after publication. In order to train a citation count prediction model, we employed artificial neural network which is a powerful machine learning tool with recently growing applications in many domains including image and text processing. The empirical experiments show that our proposed method outperforms state-of-the-art methods with respect to the prediction accuracy in both yearly and total prediction of the number of citations.  相似文献   
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Recent privacy-related incidents of mobile services have shown that app stores and providers face the challenge of mobile users’ information privacy concerns, which can prevent users from installing mobile apps or induce them to uninstall an app. In this paper, we investigate the role of app permission requests and compare the impact on privacy concerns with other antecedents of information privacy concerns, i.e., prior privacy experience, computer anxiety, and perceived control. To test these effects empirically, we conducted an online survey with 775 participants. Results of our structural equation modeling show that prior privacy experience, computer anxiety, and perceived control have significant effects on privacy concerns. However, concerns for app permission requests have approximately twice as much predictive value than the other factors put together to explain mobile users’ overall information privacy concerns. We expect that our findings can provide a theoretical contribution for future mobile privacy research as well as practical implications for app stores and providers.  相似文献   
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Compared with fully face-to-face or online learning environments, implementation of hybrid learning spaces is costly given the spaces making all learning options available for learners. Therefore, decisions on investments in hybrid learning are critical for institutions. Satisfaction and experience of learners is one of the important indicators for assessing the cost-effectiveness of learning space implementation; thus, predictions of learners' satisfaction and experience can inform institutions' decision making on learning space investments. Moreover, learning competences are found correlated with learners' satisfaction and experience in general and e-learning settings. Therefore, the present study aimed at exploring predictive learning competences for hybrid learners' experience and satisfaction. A hybrid learning space was built upon a proposed model at Shanghai Open University. 211 students’ learning competences and their satisfaction and experience in the hybrid learning space were examined. The results showed that except cognitive engagement competence, most predictive competences were not significantly associated with hybrid learners' satisfaction and experience. The findings indicated that since hybrid learning keeps all options available, to experience satisfying learning, students need not have certain competences but cognitive engagement competence, which is correlated with learners' cognitive ability to figure out the right mix of learning options.  相似文献   
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Journal of Zhejiang University-SCIENCE B - Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. It is abundant in marsh gas, livestock rumination, and...  相似文献   
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Web 2.0 changed everyday life in many aspects, including the whole system that orbits around the purchase of products and services. This revolution necessarily involved also companies, because customers became increasingly demanding. The diffusion of social media platforms pushed customers to prefer this channel for quickly obtaining information and feedback about what they want to buy, as well as for asking help after the selling. In this framework, many organisations adopted a new way of providing assistance known as social customer care. A direct link to companies allows customers to obtain real-time solutions. In this paper, we introduce a new strategy for automatically managing the information listed in the requests that customers send to the social media accounts of companies. Our proposal relies on the use of network techniques for extracting high-level structures from texts, highlighting the different concepts expressed into the customers’ written requests. The texts can be then organised on the basis of this new emerging information. An application to the requests sent to the AppleSupport service on Twitter shows the effectiveness of the strategy.  相似文献   
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Rechargeable magnesium batteries have received extensive attention as the Mg anodes possess twice the volumetric capacity of their lithium counterparts and are dendrite-free. However, Mg anodes suffer from surface passivation film in most glyme-based conventional electrolytes, leading to irreversible plating/stripping behavior of Mg. Here we report a facile and safe method to obtain a modified Mg metal anode with a Sn-based artificial layer via ion-exchange and alloying reactions. In the artificial coating layer, Mg2Sn alloy composites offer a channel for fast ion transport and insulating MgCl2/SnCl2 bestows the necessary potential gradient to prevent deposition on the surface. Significant improved ion conductivity of the solid electrolyte interfaces and decreased overpotential of Mg symmetric cells in Mg(TFSI)2/DME electrolyte are obtained. The coated Mg anodes can sustain a stable plating/stripping process over 4000 cycles at a high current density of 6 mA cm−2. This finding provides an avenue to facilitate fast ion diffusion kinetics of Mg metal anodes in conventional electrolytes.  相似文献   
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