Super-twisting observer-based sliding mode control with fuzzy variable gains and its applications to fully-actuated hexarotors

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.     

‘Forgotten’ democracy,student activism,and higher education in Myanmar: past,present, and future

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...     

Extract from new understandings of teachers' pedagogic knowledge 1

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.     

Radiant flux through apertures—I

Equations for the calculation of radiant power F through two apertures in series are well known. A characteristic of these formulae is that they give F as a small difference between two large terms. Evidently, the flux through the apertures must decrease as the spacing between them increases; and for large spacing, the inverse-square relation must hold. Instead of exhibiting this behaviour in an obvious manner, however, the traditional equations give the specious impression of an increase in F with increase in spacing. The paper develops an approximate formulae that applies to apertures in the shape of any regular polygon and that shows clearly how the inverse square relation is approached for large separation.     

Exploring the forward citation patterns of patents based on the evolution of technology fields

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.     

Roller skiing biomechanical information analysis using GPS,IMU, and atmospheric pressure sensors: a case study

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.     

The Law of Mass Communications

David G. Clark and Earl R. Hutchinson, Mass Media and the Law: Freedom and Restraint (Wiley-Interscionco, $12.95)

John M. Kittross and Konnoth Harwood, Free & Fair: Courtroom Access and the Fairness Doctrino (Journal of Broadcasting, Temple University, $3.95)

Paul W. MacAvoy's The Crisis of the Regulatory Commissions: An Introduction to a Current Issue of Public Policy (Norton, $5.95; paper, $2.95)

Eric Moon, Book Selection and Consorship in the Sixties (Hawker, $10.95)

Edward De Grazia's Censorship Landmarks (Hawker, $19.75)