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1.
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
2.
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
3.
Morphological and biochemical responses of Oryza sativa L. (cultivar MR219) to ion beam irradiation 总被引：1，自引：0，他引：1
Anna Pick Kiong Ling Ying Chian Ung Sobri Hussein Abdul Rahim Harun Atsushi Tanaka Hase Yoshihiro 《Journal of Zhejiang University. Science. B》2013,14(12):1132-1143
Objective
Heavy ion beam, which has emerged as a new mutagen in the mutation breeding of crops and ornamental plants, is expected to result in the induction of novel mutations. This study investigates the morphological and biochemical responses of Oryza sativa toward different doses of carbon ion beam irradiation.Methods
In this study, the dry seeds of O. sativa were irradiated at 0, 20, 40, 60, 80, 100, and 120 Gy, followed by in-vitro germination under controlled conditions. Morphological and biochemical studies were conducted to investigate the morphological and physiological responses of O. sativa towards ion beam irradiation.Results
The study demonstrated that low doses (10 Gy) of ion beam have a stimulating effect on the height, root length, and fresh weight of the plantlets but not on the number of leaves. Meanwhile, doses higher than 10 Gy caused reductions in all the morphological parameters studied as compared to the control samples. The highest total soluble protein content [(2.11±0.47) mg/g FW] was observed in plantlets irradiated at 20 Gy. All irradiated plantlets were found to have 0.85% to 58.32% higher specific activity of peroxidase as compared to the control samples. The present study also revealed that low doses of ion beam (10 and 20 Gy) had negligible effect on the total chlorophyll content of O. sativa plantlets while 40 Gy had a stimulating effect on the chlorophyll content. Plantlets irradiated between 40 to 120 Gy were shown to be 0.38% to 9.98% higher in total soluble nitrogen content which, however, was not significantly different from the control samples.Conclusions
Carbon ion beam irradiation administered at low to moderate doses of 10 to 40 Gy may induce O. sativa mutants with superior characteristics. 相似文献4.
5.
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.
相似文献6.
Jeffery H. Marshall Ung Chinna Ung Ngo Hok Souer Tinon Meung Veasna Put Nissay 《Educational Assessment, Evaluation and Accountability》2012,24(2):113-134
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
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8.
Bic Ngo 《Equity & Excellence in Education》2013,46(2):115-124
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
9.
Helen Hok‐Sze Leung 《Inter-Asia Cultural Studies》2013,14(4):559-571
Abstract This article argues for the revitalization of a productive tension between ‘queer’ and ‘theory’ and underscores its necessity for a study of ‘local queer theory.’ While there is an apparent lack of academic queer theory in Hong Kong, there are numerous examples of writings that advance theoretical positions, albeit in unfamiliar guises. The article analyzes three examples of queer writings by Hong Kong authors, penned between 1984 and 2000. Focusing on the texts’ archival effect and affective expression, the analysis demonstrates that these writings form an archive of queer feelings. As a repository of the discomfort and anxiety that are constitutive of queer lives, these writings can offer fruitful interventions into current theoretical debates. The article concludes with a call for more creative and irreverent – in short, queerer – ways of localizing the global phenomenon of queer theory. 相似文献
10.
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