Natural surface design for sliding mode control with multiple discontinuous inputs

It is well known that sliding mode control is based on the definition of an invariant manifold, where the system dynamics are forced to in a finite time. Such a manifold is somewhat arbitrarily defined, as long as the system dynamics are stable on it. Computational and control effort may vary depending on selected manifold. Obviously, if a system has naturally acceptable stable dynamics around a desired equilibrium point, no control is needed unless uncertainties or disturbances are present. It would be desirable that if such a system had uncertainties or disturbances, the control effort be designed only to overcome the effect of such factors. For a system with first order dynamics and affine control input, designing a sliding mode control overcoming only such uncertainties or disturbances is a trivial task. When a higher order dynamics system is involved, unit control may be used, where the input control signals are not discontinuous, but when only discontinuous control inputs are available, a design approach is not readily available. In this paper, taking advantage of the natural stable dynamics of a system, a sliding mode control approach is introduced for designing multiple discontinuous control inputs, where the control effort overcomes only uncertainties, disturbances or unstable dynamics. Two illustrative examples are given in order to show the feasibility of the method.     

Application of a lexical-semantic intervention programme for students with Specific Language Impairment / Aplicación de un programa de intervención léxico-semántica en alumnado con Trastorno Específico del Lenguaje

The aim of this research has been to test the efficacy of an intervention programme on lexical-semantic problems in children with Specific Language Impairment (SLI). The sample consisted of 34 children diagnosed with SLI and 34 children with typical language development, all enrolled in different schools on the island of Tenerife (Canary Islands, Spain). For the selection of the sample, CELF-3, Peabody, ITPA Auditory Association and Visual Association subtests and the K-BIT IQ tests were used. The intervention programme consisted of 72 sessions of 30 minutes each, using noun and action naming activities along with conversation and categorization tasks in order to increase vocabulary and improve lexical semantic competence. Significant results were achieved in aspects related to the acquisition of vocabulary as well as in lexical semantics or related terms. The educational implications are clear insofar as lexical-semantic aspects are key in terms of activating other linguistic components and in improving the academic progress of SLI students.     

Is there an ethics of algorithms?

We argue that some algorithms are value-laden, and that two or more persons who accept different value-judgments may have a rational reason to design such algorithms differently. We exemplify our claim by discussing a set of algorithms used in medical image analysis: In these algorithms it is often necessary to set certain thresholds for whether e.g. a cell should count as diseased or not, and the chosen threshold will partly depend on the software designer’s preference between avoiding false positives and false negatives. This preference ultimately depends on a number of value-judgments. In the last section of the paper we discuss some general principles for dealing with ethical issues in algorithm-design.     

Tweet Up? Examining Twitter's Impact on Social Capital and Digital Citizenship in Higher Education

Twitter is a highly accessible communication venue that is embraced by great numbers of traditionally aged and ethnically diverse college students. Danielle Morgan Acosta challenges us to turn our research and teaching attention to the potential of Twitter to support student learning.     

Stichwort: Umgang mit Wissen

Ohne Zusammenfassung      

Simulating Oppression: Digital Gaming,Race and the Education of African American Children

Educational game designers and educators are using digital games as a platform for teaching academic content, including multicultural curriculum. However, it is unclear how well digital game-based learning can coexist with the goals of multicultural education for the purpose of meeting the needs of African American children. In this essay, we raise serious questions about the use of digital games to teach about social oppression in ways that privilege the psychological well-being of African American children. We argue that digital games that intend to recreate histories of racial oppression can be harmful to African American children if they reproduce popular and problematic notions of indigenous lives and experiences. We illuminate some of the dangers of such digital games through a preliminary exploration of one digital game designed to teach about facets of African American enslavement. Our essay concludes with recommendations for culturally relevant digital game-based learning design and instruction.     

Mental attention in gifted and nongifted children

The relationship between the construct of mental attention and “giftedness” is not well established. Gifted individuals could make effective use of their executive functions and this could be related to their mental attentional capacity. The dialectic constructivist model developed by Pascual-Leone introduced the concept of mental attention or “effort”, relating it to mental capacity. The aim of this study is to investigate whether the measurement of mental capacity (M-measurement) is differential for a group of children with high IQs. 110 students between 4 and 18 years old participated in this study. Some were Gifted (n=70) and others Non-Gifted (n=40). Wechsler-R Scale and the Figural Intersection Test were administered to all participants. An interesting pattern was found in the younger groups. The gifted scored higher than the non-gifted in the Figural Intersection Test and much higher than their theoretical M. The non-gifted scored quite close to their theoretical M (based on age). In the oldest group, the gifted again achieved higher scores, but now they scored at the theoretical level, and the non-gifted underperformed.     

Students and society in the 2020s. Three future ‘histories’ of education and technology

ABSTRACT

As social science fiction, this paper imagines three possible futures for education and technology. Among the most important technologies emerging today are data-aggregating technologies such as AI, affective computing, adaptive or predictive software, clouds and platforms. The paper is not, however, directed at specific technologies, but at indeterminate sociotechnical configurations. Set in 2040, it offers three ‘histories’ of the 2020s. Might students become (i) ‘smooth users’, improving themselves in the pursuit of frictionless efficiency within a post-democratic frame created by large corporations, (ii) ‘digital nomads’, seeking freedom, individualism and aesthetic joy as solopreneurs exploiting state regulations and algorithmic rules while stepping out of the state and deeply into the capitalist new economy, or (iii) participatory, democratic, ecological humans embedded in ‘collective agency’ that see institutions as spaces for exploring more equitable ways of living? The paper reflects on the future research and the political, educational and technological decisions which would make each of these three fictional future histories more or less likely.     

Negotiating diversity: an empirical investigation into family,school and student factors influencing New Zealand adolescents’ science literacy

The purpose of this study was to examine a factor triad consisting of family, school and student variables contributing to New Zealand adolescents’ science literacy performance on Programme for International Student Assessment 2006. Results indicated that the selected variables in our study explained 25% of total differences in New Zealand students’ science achievement. Family socio-economic status (SES) as well as adolescents’ motivation to learn science and general value of science were influential factors in students’ science achievement. Findings also revealed a statistically significant interaction effect between SES and first-generation immigrant students but not between SES and second-generation immigrant students. Although parents’ perception of general value of science showed a positive effect on adolescents’ scientific performance, its predictive power was relatively weak.