In this paper, we consider the super-twisting observer-based sliding mode control algorithm with fuzzy variable gains (STOSMC) for the fully-actuated hexarotor. Our hexarotor has full actuation due to six titled propellers that allows to control position and orientation (attitude) simultaneously, and resolves the singularity problem of the rotational matrix by using the quaternion modeling framework. We show that the proposed STOSMC for the hexarotor guarantees finite-time convergence of the estimation error and asymptotic stability of the hexarotor. In simulations, we demonstrate the nonsingularity and fully-actuated control performance of the hexarotor by considering extreme position and attitude control scenarios. Moreover, the simulation results show that the hexarotor achieves the fast and precise tracking performance to the desired position and the desired attitude and the chattering phenomenon is reduced compared with the fixed-gains observer-based super-twisting sliding mode control due to the fuzzy mechanism. 相似文献
This article examines the policy cycle and vernacular globalization in the context of higher education reform in Vietnam. Through an analysis of the development of the Vietnam National University—Hochiminh City as part of the post‐1986 reconstruction of Vietnamese higher education, the article considers the complex interrelationship between globalized policy discourses, national interests and history in Vietnam, and the specific politics of policy implementation within one institution. Vietnam National University—Hochiminh City was created through an amalgamation of a number of smaller universities, and against the backdrop of social and economic restructuring aimed at promoting industrialization and a market orientation within socialist governance. The article reveals the dynamic tension between these local and global influences on higher education policy and practice, and more specifically, the dilemmas associated with top‐down policy implementation when a new organization consists of older organizations with powerful provenance and reputations. In so doing the article demonstrates the necessity to globalize policy theory. 相似文献
This study investigates the link between basic math skills, remediation, and the educational opportunity and outcomes of community college students. Capitalizing on a unique placement policy in one community college that assigns students to remedial coursework based on multiple math skill cutoffs, I first identify the skills that most commonly inhibit student access to higher-level math courses; these are procedural fluency with fractions and the ability to solve word problems. I then estimate the impact of “just missing” these skill cutoffs using multiple rating-score regression discontinuity design. Missing just one fractions question on the placement diagnostic, and therefore starting college in a lower-level math course, had negative effects on college persistence and attainment. Missing other skill cutoffs did not have the same impacts. The findings suggest the need to reconsider the specific math expectations that regulate access to college math coursework.
The global spread of national assessment testing activities, and the growing pressure to move beyond basic measures of participation
in educational monitoring, means that student achievement measures are likely to become increasingly relevant indicators of
systemic progress in the developing world. Using data from the CESSP project in Cambodia, this paper incorporates a standard
decomposition framework to go beyond simple comparisons of average achievement levels over time in order to better understand
the underlying dynamics of change. The results show that recent improvements in student achievement in Cambodia are attributable
in part to changes in the composition of student cohorts, although there is some evidence of a tradeoff between increasing
participation rates and average achievement. There is also some encouraging evidence that school quality is improving, especially
in lower grades where the leveling off of participation is creating a policy window of opportunity. The framework can be easily
applied to a growing body of assessment data in the developing world to aid both inter- and intra-national monitoring of education
system progress. 相似文献
In this article, I draw on poststructuralist work on "citationality" to elucidate an urban high school's student culture and intervention efforts with regard to LGBQ issues. I contend that the language, ideas and practices of LGBQ issues and awareness among students and staff "cite" or draw on broader (and often competing) discourses of normalcy, sexuality, and/or "good teaching." I discuss how the citational process makes it difficult to bring about change, as well as the possibilities for bringing about change. The significance of this article is the way it explicates the discourses used to articulate and describe LGBQ people, issues, and intervention efforts; and how these discourses may hinder efforts to create LGBQ support and awareness in schools. 相似文献
Using the theory of reasoned action in combination with the Competing Values Framework of organizational leadership, our study examines how deans at Indonesian universities lead and manage their faculties. Based on a large-scale survey with responses from more than 200 Indonesian deans, the study empirically identifies a number of deanship styles: the Master, the Competitive Consultant, the Focused Team Captain, the Consensual Goal-Setter and the Informed Trust-Builder style. Further, the study investigates determinants of deans’ leadership styles, pointing at the important role of their attitudes towards leadership, while their perceived behavioural control only explains some of the styles. The study also suggests that faculty culture is important to take into consideration if we want to gain further understanding of the deanship, since culture turned out to effect the deans’ attitudes and hence their leadership style. 相似文献
Vygotsky’s sociocultural theory (VST) has been increasingly utilised as an effective framework to account for the role of emotions in learning and development. Yet, within VST, emotion has neither been systemically theorised nor investigated. This paper contributes to the literature by offering a theoretical discussion of Vygotsky’s perspective on emotion and its relation to cognition. Employing a content analysis approach, three of Vygotsky’s key texts on emotions were closely read and analysed with emerging themes grouped into a system of interrelated theoretical tenets. The insights gained from this paper benefit scholars who are interested in understanding and researching emotions from a VST perspective as well as provide important implications for educational practices.
Research in Science Education - Students’ difficulties interpreting diagrams remain a concern in science education. Research about improving diagram comprehension has included few studies of... 相似文献
