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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.
Forward citations of patents have been used extensively to capture the impact of technological knowledge. However, our understanding of the factors shaping patent citation patterns remains limited. One of the main limitations is the lack of scholarly attention paid to the dynamic influences arising from the evolution of technology fields. From an evolutionary perspective, technological impact is not simply determined by the static attributes of a technology itself; it is also dynamically affected by changes in the external conditions. Drawing on this viewpoint, this study suggests a model for understanding patent citation patterns by reflecting the evolution of the technology fields to which each patent belongs. Four such factors are explored: technology cycle time, potential of technological convergence, popularity of the technology field, and technological novelty. Based on the proposed model, we show how expected citation patterns can change as a result of different scenarios for technology field evolution. We conduct a case study of patents in the information technology and healthcare industries to show citation patterns of patents across heterogeneous industries as well as those within an industry. Contributions to the innovation literature and research investment decisions are discussed.  相似文献   
3.
The purpose of this research was to propose a method to acquire the three-dimensional movement of a roller skiing athlete utilizing a global positioning system (GPS), an atmospheric pressure sensor (APS), and an inertial measurement unit (IMU) to distinguish between diagonal skiing and double poling techniques. In this study, we developed a lightweight wearable sensor that was composed of a GPS, APS, and IMU. For the data collection, two national level athletes roller skied a 1700 m long course where the maximum difference in elevation was 5.3 m. The planar positions of the athletes were based on the longitudinal and latitudinal data provided by the GPS, and the altitude was calculated by the International barometric formula and Laplace transform from the APS. The longitudinal and latitudinal data acquired through GPS had errors within 2 m range at each point. The altitude of Laplace transform from the APS showed errors of less than 1 m at each point. The range of motion of pelvis from the IMU was 34.0?±?3.8° for diagonal skiing, which is wider than the 21.2?±?6.9° for double poling.  相似文献   
4.
香港特别行政区高校从2015年开始,学生学业评估陆续由常模参照评估转为标准参照评估。本文以香港中文大学通识教育基础课程实施标准参照评估的行动为案例,分析了这项新的学业评估方式在实施中所遇到的问题,讨论了解决方法并提出实施模型。该模型包含评分量表的设计与开发、量表使用、教师意见反馈与量表修改,以及评分之后的集体讨论这一套实施流程。文章最后指出,要保证标准参照评估的有效实施,需建立教师实践共同体。实践共同体的行动包括:教师共同开发评估标准,通过集体讨论对评估标准的含义和使用达成共识,共同审视评估结果,根据评估结果进一步修改和完善评估标准。  相似文献   
5.
Asia Pacific Education Review - This paper is a historical examination of higher education in contemporary Myanmar, and its relationship to the students, the most important and visible actor in...  相似文献   
6.
This article presents an innovative methodology to study computer-mediated communication (CMC), which allows analysis of the multi-layered effects of online expression and reception. The methodology is demonstrated by combining the following three data sets collected from a widely tested eHealth system, the Comprehensive Health Enhancement Support System (CHESS): (1) a flexible and precise computer-aided content analysis; (2) a record of individual message posting and reading; and (3) longitudinal survey data. Further, this article discusses how the resulting data can be applied to online social network analysis and demonstrates how to construct two distinct types of online social networks—open and targeted communication networks—for different types of content embedded in social networks.  相似文献   
7.
The University of Oklahoma College of Medicine has conducted an annual Anatomical Donor Luncheon where families of the anatomical donors met anatomy dissection groups of medical students. The luncheon presented an opportunity for donor family members to share the life story of their loved one with the medical students prior to the start of the anatomy course. This study was designed to understand the impact of the Anatomical Donor Luncheon on families of the donors. Seven families in two different focus groups were included to explore the reactions and attitudes of the donor families to meeting the medical students. Conversations were digitally recorded and transcribed. Qualitative analysis of textual data were coded by three investigators using the Constant Comparative Method. To provide evidence of validity, a form of member checking was utilized. For further triangulation, an analyst not involved in conducting the focus groups or analyzing the data, re-coded all data. This analyst used categories and themes identified by the original analysts, ensuring validity of the themes and any negative cases (data not supporting or contradictory of the established categories and themes). One meta-theme and three sub-themes were identified. The meta-theme was Donor Family Participants Experience Transformation and Closure, and sub-themes were Motivators for Participation, Optimal Venue Factors, and Optimal Medical Student–Anatomical Donor Family Interactions. Study findings indicated the Anatomical Donor Luncheon facilitated closure on the death of their loved one, and transformed their apprehension about the luncheon and body donation into an attitude of gratitude and appreciation.  相似文献   
8.
The purpose of this study was to investigate the accuracy of fat-free mass (FFM) estimates from two-compartment (2C) models including air displacement plethysmography (ADP), ultrasound (US), near-infrared interactance (NIR), and the Jackson and Pollock skinfold equation (SKF) against a criterion four-compartment (4C) model in elite male rowers. METHODS: Twenty-three elite-level male rowers (mean± SD; age 24.6 ± 2.2 years; stature: 191.4 ± 7.2 cm; mass: 87.2 ± 11.2 kg) participated in this investigation. All body composition assessments were performed on the same day in random order, except for hydrostatic weighing (HW), which was measured last. FFM was evaluated using a 4C model, which included total body water from bioimpedance spectroscopy, body volume from HW, and total body bone mineral via dual-energy X-ray absorptiometry. The major findings of the study were that the 2C models evaluated overestimated FFM and should be considered with caution for the assessment of FFM in elite male rowers. Future studies should use multiple-compartment models, with measurement of TBW and bone mineral content, for the estimation of FFM.  相似文献   
9.
From a multicultural perspective, this research investigated to what extent Korean mathematics textbooks use history of mathematics. The results show even though educational use of history presented in Korean mathematics textbooks may provide a rich outlook, it does not encourage a fundamental change in the educational practice of school mathematics that has traditionally been entrenched in the Eurocentric narrative of mathematics. This suggests that the mathematics textbooks were not organized effectively to promote students’ understanding of diversity. Based on the results, we discuss the implications for the development of mathematics textbook from multicultural perspectives.  相似文献   
10.
Abstract

The focus of this article is a comparative review of the science curriculum for England and Wales from the perspective of recent developments in the United States of America, Australia, New Zealand and the Canadian province of Ontario. In the comparison of science curriculum documents and the language deployed, questions are raised about differences as well as commonalities among and between documents from various jurisdictions. Issues discussed include: the varying emphases upon science topics and/or intended learning outcomes; integration with other curriculum areas; the content and organization of the science curriculum; and ways of assessing students’ performances and understandings. The article draws attention to the importance of comparative analysis which informs our understanding of the effects of curriculum change, its relation to students’ achievements in science, and the need to support the development of teachers.  相似文献   
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