Extended-state-observer-based output feedback adaptive control of hydraulic system with continuous friction compensation     

Chengyang Luo  Jianyong Yao  Jason Gu 《Journal of The Franklin Institute》2019,356(15):8414-8437

This paper presents an extended state observer-based output feedback adaptive controller with a continuous LuGre friction compensation for a hydraulic servo control system. A continuous approximation of the LuGre friction model is employed, which preserves the main physical characteristics of the original model without increasing the complexity of the system stability analysis. By this way, continuous friction compensation is used to eliminate the majority of nonlinear dynamics in hydraulic servo system. Besides, with the development of a new parameter adaption law, the problems of parametric uncertainties are overcome so that more accurate friction compensation is realized. For another, the developed adaption law is driven by tracking errors and observation errors simultaneously. Thus, the burden of extended state observer to solve the remaining uncertainties is alleviated greatly and high gain feedback is avoided, which means better tracking performance and robustness are achieved. The designed controller handles not only matched uncertainties but also unmatched dynamics with requiring little system information, more importantly, it is based on output feedback method, in other words, the synthesized controller only relies on input signal and position output signal of the system, which greatly reduces the effects caused by signal pollution, measurement noise and other unexpected dynamics. Lyapunov-based analysis has proved this strategy presents a prescribed tracking transient performance and final tracking accuracy while obtaining asymptotic tracking performance in the presence of parametric uncertainties only. Finally, comparative experiments are conducted on a hydraulic servo platform to verify the high tracking performance of the proposed control strategy.  相似文献   

Mediating a compromised solidarity     

Jason Vincent A. Cabañes 《Popular Communication》2019,17(2):109-124

ABSTRACT

This article explores popular media as resources for judgment in how settled migrants in Europe imagine solidarities toward newer arrivals seeking entry into the region. It discusses the news and entertainment consumption of Filipino nurses in London and how this figures in their imaginary of social and political bonds with refugees. Drawing on ethnographic interviews, I argue that these Filipino migrants can only articulate a compromised solidarity: one fractured between empathy with refugees and concern about what these newer arrivals might mean for settled migrants in the city. I then explain how the media contribute to this fracturing. One way is that the xenophobia in popular media content on social media leads the Filipinos to assert their difference with other migrants, including refugees. A second is that the Filipinos deploy popular media content, especially on British television, to assert that they belong to UK society more than other migrants, again including refugees.  相似文献   

Mr Collier’s Letter Racks. A Tale of Art And Illusion At The Threshold of the Modern Information Age     

Jason Peacey 《Media History》2018,24(1):142-145

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Courting Apocalypse: Creating a Zombie-Themed Evidence-Based Medicine Game     

Amy E. Blevins  Elizabeth Kiscaden  Jason Bengtson 《Medical reference services quarterly》2017,36(4):313-322

In 2015, two librarians at the Hardin Library for the Health Sciences at the University of Iowa turned their dreams into a reality and secured funding to build a zombie-themed evidence-based medicine game. The game features a “choose your own adventure” style that takes students through a scenario where a disease outbreak is taking place and a resident is asked to use evidence-based medicine skills to select a screening and diagnostic tool to use on potentially infected patients. Feedback on the game has been positive, and future plans include building additional modules on therapy, harm, and prognosis.  相似文献   

The Interaction of Early Maternal Responsiveness and Children's Cognitive Abilities on Later Decoding and Reading Comprehension Skills     

Heather B. Taylor  Jason L. Anthony  Rachel Aghara  Karen E. Smith  Susan H. Landry 《Early education and development》2008,19(1):188-207

This longitudinal study evaluated the extent to which maternal responsiveness across early childhood and children's cognitive skills predicted children's 8-year decoding and reading comprehension skills for children who varied in biological risk (term, n = 83; preterm, n = 155). Patterns of maternal responsiveness during infancy (6, 12, and 24 months) and preschool (3 and 4 years) revealed 4 maternal clusters that varied in consistency and level of maternal responsiveness. Although not predictive of decoding skills, the interaction between children's 4-year cognitive ability and maternal responsiveness cluster predicted children's reading comprehension skills at 8 years of age, regardless of risk. Although consistently high levels of maternal responsive parenting across early childhood related to literacy outcomes for all children in the study, responsive parenting had a stronger relation to later reading comprehension skills for children with lower cognitive abilities, particularly when mothers demonstrated high responsiveness in children's infancy.  相似文献   

Changes in metacognitive monitoring accuracy in an introductory physics course     

Morphew  Jason W. 《Metacognition and Learning》2021,16(1):89-111

Metacognition and Learning - Student learning in introductory science, technology, engineering, and mathematics (STEM) courses is often self-regulated. For self-regulated learning to be effective,...  相似文献   

Faculty Liaisons: an embedded approach for enriching teaching and learning in higher education     

Afsaneh Sharif  Ashley Welsh  Jason Myers  Brian Wilson  Judy Chan  Sunah Cho 《International Journal for Academic Development》2019,24(3):260-271

This paper explores the experiences of a group of academic developers who support educational development work as Faculty Liaisons at a large, research-intensive university. These academic developers inhabit complex ‘third spaces’, providing support through an embedded partnership relationship that requires lateral movement across functional and organizational boundaries to create new professional spaces, knowledge, and relationships. The authors utilize narrative inquiry and auto-ethnographic approaches to present an interpretive qualitative analysis of their experiences supporting Faculty and University projects across complex and evolving organizational boundaries. From this analysis, they highlight key roles and responsibilities associated with their blended context and identify challenges that academic developers who occupy third spaces within academic organizations face as they negotiate competing interests, identities, and requirements associated with the diverse range of their projects and the blended experience of working in scholarly and administrative, central- and Faculty-based roles. The lessons they have learned from these experiences will be of particular interest to academic developers who are experiencing the flux of change within higher education settings that are impacting teaching and learning practices both for faculty in the classroom and for those across the institution who support them.  相似文献   

Facial expressions when learning with a Queer History App: Application of the Control Value Theory of Achievement Emotions     

Byunghoon “Tony” Ahn  Jason M. Harley 《British journal of educational technology : journal of the Council for Educational Technology》2020,51(5):1563-1576

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Legacies of Brown versus Board: An Introduction to the Special Issue     

George W. Noblit  Jason C. Mendez 《The Urban Review》2008,40(1):1-4

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Impacts of Globalization on E-Commerce Use and Firm Performance: A Cross-Country Investigation     

Kenneth L. Kraemer  Jennifer Gibbs  Jason Dedrick 《The Information Society》2005,21(5):323-340

This article develops and tests a model examining the relationship between firm globalization, scope of e-commerce use, and firm performance, using data from a large-scale cross-country survey of firms from three industries. We find that globalization leads to both greater scope of e-commerce use and improved performance, measured as efficiency, coordination, and market impacts. Scope of e-commerce use also leads to greater firm performance of all three types. Globalization has differential effects on B2B and B2C e-commerce, however, such that highly global firms are more likely to do B2B but less likely to do B2C. Our findings provide support for Porter's (1986) thesis that upstream business activities (namely, B2B) are more global while downstream business activities (B2C) are more local or multidomestic.  相似文献