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11.
In this paper a new integrated observer-based fault estimation and accommodation strategy for discrete-time piecewise linear (PWL) systems subject to actuator faults is proposed. A robust estimator is designed to simultaneously estimate the state of the system and the actuator fault. Then, the estimate of fault is used to compensate for the effect of the fault. By using the estimate of fault and the states, a fault tolerant controller using a PWL state feedback is designed. The observer-based fault-tolerant controller is obtained by the interconnection of the estimator and the state feedback controller. We show that separate design of the state feedback and the estimator results in the stability of the overall closed-loop system. In addition, the input-to-state stability (ISS) gain for the closed-loop system is obtained and a procedure for minimizing it is given. All of the design conditions are formulated in terms of linear matrix inequalities (LMI) which can be solved efficiently. Also, performance of the estimator and the state feedback controller are minimized by solving convex optimization problems. The efficiency of the method is demonstrated by means of a numerical example.  相似文献   
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This article reflects my experiences of learning art in the 1970s and 1980s and my teaching career in school art education in twenty‐first century South Korea. This autobiographical reflection shows how I have struggled with my identity as an art teacher in the post‐colonial context of Western influences on Korean society since World War II. There has been greater tension and a greater struggle for different values, practices and identities when new values and practices have been introduced into the particular socio‐cultural context of South Korea. My struggles with particular kinds of pedagogic identity valued within the rapidly changing political, economic and cultural context of Western influences on Korean art education demonstrate the hidden structural mechanism of the relationship between culture, power and identity in the post‐colonial world of globalisation. This study as an autoethnographical research provides critical insights into how identities are produced by pedagogic discourses and practices of art education that are constructed through the specific systems of practice and language which transmit and regulate such identities and values.  相似文献   
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Journal of Science Education and Technology - The properties and functions of complex systems apply across a variety of domains of science and are at the heart of the solutions to many global...  相似文献   
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This study examined the structural relationships among perceived school support, transformational leadership, teachers’ work engagement, and teachers’ knowledge creation practices. It also investigated the mediating effects of transformational leadership and work engagement in explaining the association between perceived school support and knowledge creation practices. Samples included 284 career and technical education teachers in the United States. Structural equation modeling was employed. Perceived school support was positively associated with transformational leadership and teachers’ work engagement, but had no direct impact on knowledge creation practices. Transformational leadership was found to affect knowledge creation practices, but not work engagement of teachers. Although a supportive school climate had no direct relationship with knowledge creation practices, it indirectly affected this outcome variable through transformational leadership and teachers’ work engagement. The results suggest that in order to increase teachers’ knowledge creation activities, a supportive school climate should be provided with efforts to improve teachers’ work engagement and transformational behaviors of the principal.  相似文献   
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ABSTRACT

In this article, the authors introduce a novel way, using the metaphor of a baseball game, to evaluate and measure community college student progress for those whose stated goal is to transfer to a 4-year institution and, ultimately, earn a bachelor's degree. The proposed framework of “the Transfer Game” is an outgrowth of the Transfer and Retention of Urban Community College Students (TRUCCS) project, which is a longitudinal study of 5,000 community college students from the 9-campuses of the Los Angeles Community College District. The goal of the project is to explain how the “all-American game” provides a method to measure, comprehend, and visualize student progression, and identify the factors that predict both success and barriers. The framework provides a scholarly comparison of the all-American game of baseball to the All-American invention of the community college.  相似文献   
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ABSTRACT

Research on media substitution theory has examined substitutional and/or complementary relationships between new and existing media. This study focuses on the growth of mobile platforms and investigates the relationship between mobile devices and personal computers. Using Nielsen’s panel data that provide electronically recorded media usage (N = 2,396), this study analyzes yearly changes in time allocation to mobile devices and PCs at total and content-specific usage levels during mobile 4G transition. Results suggest a complementarity dynamic between mobile devices and PCs; however, the patterns were more nuanced in light of the role of individual and structural factors when determining media choice.  相似文献   
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Soft robotics with new designs, fabrication technologies and control strategies inspired by nature have been totally changing our view on robotics. To fully exploit their potential in practical applications, untethered designs are preferred in implementation. However, hindered by the limited thermal/mechanical performance of soft materials, it has been always challenging for researchers to implement untethered solutions, which generally involve rigid forms of high energy-density power sources or high energy-density processes. A number of insects in nature, such as rove beetles, can gain a burst of kinetic energy from the induced surface-energy gradient on water to return to their familiar habitats, which is generally known as Marangoni propulsion. Inspired by such a behavior, we report the agile untethered mobility of a fully soft robot in liquid based on induced energy gradients and also develop corresponding fabrication and maneuvering strategies. The robot can reach a speed of 5.5 body lengths per second, which is 7-fold more than the best reported, 0.69 (body length per second), in the previous work on untethered soft robots in liquid by far. Further controlling the robots, we demonstrate a soft-robot swarm that can approach a target simultaneously to assure a hit with high accuracy. Without employing any high energy-density power sources or processes, our robot exhibits many attractive merits, such as quietness, no mechanical wear, no thermal fatigue, invisibility and ease of robot fabrication, which may potentially impact many fields in the future.  相似文献   
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This paper proposes a set of methods and a framework for evaluating, modeling, and predicting group interactions in computer‐mediated communication. The method of sequential analysis is described along with specific software tools and techniques to facilitate the analysis of message–response sequences. In addition, the Dialogic Theory and its assumptions are presented to establish a theoretical framework and guide to using sequential analysis in computer‐mediated communication research. Step‐by‐step instructions are presented to illustrate how sequential analysis can be used to measure the way latent variables (e.g., message function, response latency, communication style) and exogenous variables (e.g., gender, discourse rules, context) affect how likely a message is to elicit a response, the types of responses elicited by the message, and whether or not the elicited sequence of responses (e.g., claim → challenge → explain) mirror the processes that support group decision‐making, problem‐solving, and learning.  相似文献   
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