Global real-time optimization by output-feedback extremum-seeking control with sliding modes

This paper addresses the design of a sliding mode based extremum-seeking controller for a class of single-input–single-output (SISO) uncertain nonlinear systems with unmatched and state-dependent strong nonlinearities. We demonstrate that it is possible to achieve an arbitrarily small neighborhood of the desired optimal point using only output-feedback. The key idea is the combination of a periodic switching function with a norm state observer. As an important advantage, we show that the proposed scheme achieves extremum-seeking for all initial conditions, i.e., the real-time optimization algorithm has global convergence properties. An application to a simple nonderivative optimizer illustrates the viability of the proposed approach.     

“Kindergarten, can I have your eyes and ears?” politeness and teacher directive choices in inquiry-based science classrooms

This study explores elementary teachers’ social understandings and employment of directives and politeness while facilitating inquiry science lessons prior and subsequent to their participation in a summer institute in which they were introduced to the scholarly literature on regulative discourse (directives used by teachers to regulate student behavior). A grounded theory analysis of the institute professional development activities revealed that teachers developed an increased awareness of the authoritative functions served by impolite or direct directives (i.e., pragmatic awareness). Furthermore, a comparative microethnographic analysis of participants’ inquiry-based classroom practices revealed that after the institute teachers demonstrated an increased ability to share authority with students by strategically making directive choices that were more polite, indirect, inclusive, involvement-focused and creative. Such ability led to a reduced emphasis on teacher regulation of student compliance with classroom behavioral norms and an increased focus on the discursive organization of the inquiry-based science learning/teaching process. Despite teachers’ increased pragmatic awareness, teacher–student linguistic relationships did not become entirely symmetrical subsequent to their participation in the summer institute (i.e., teacher authority was not completely relinquished or lost). Based on such findings, it is argued that teachers need to develop higher levels of pragmatic awareness to become effectively prepared to engage in language-mediated teacher–student interaction in the context of inquiry-based science classroom discourse.     

How and where is artificial intelligence in the public sector going? A literature review and research agenda

To obtain benefits in the provision of public services, managers of public organizations have considerably increased the adoption of artificial intelligence (AI) systems. However, research on AI is still scarce, and the advance of this technology in the public sector, as well as the applications and results of this strategy, need to be systematized. With this goal in mind, this paper examines research related to AI as applied to the public sector. A review of the literature covering articles available in five research databases was completed using the PRISMA protocol for literature reviews. The search process yielded 59 articles within the scope of the study out of a total of 1682 studies. Results show a growing trend of interest in AI in the public sector, with India and the US as the most active countries. General public service, economic affairs, and environmental protection are the functions of government with the most studies related to AI. The Artificial Neural Networks (ANN) technique is the most recurrent in the investigated studies and was pointed out as a technique that provides positive results in several areas of its application. A research framework for AI solutions for the public sector is presented, where it is demonstrated that policies and ethical implications of the use of AI permeate all layers of application of this technology and the solutions can generate value for functions of government. However, for this, a prior debate with society about the use of AI in the public sector is recommended.     

Three-feature model to reproduce the topology of citation networks and the effects from authors’ visibility on their h-index

Various factors are believed to govern the selection of references in citation networks, but a precise, quantitative determination of their importance has remained elusive. In this paper, we show that three factors can account for the referencing pattern of citation networks for two topics, namely “graphenes” and “complex networks”, thus allowing one to reproduce the topological features of the networks built with papers being the nodes and the edges established by citations. The most relevant factor was content similarity, while the other two – in-degree (i.e. citation counts) and age of publication – had varying importance depending on the topic studied. This dependence indicates that additional factors could play a role. Indeed, by intuition one should expect the reputation (or visibility) of authors and/or institutions to affect the referencing pattern, and this is only indirectly considered via the in-degree that should correlate with such reputation. Because information on reputation is not readily available, we simulated its effect on artificial citation networks considering two communities with distinct fitness (visibility) parameters. One community was assumed to have twice the fitness value of the other, which amounts to a double probability for a paper being cited. While the h-index for authors in the community with larger fitness evolved with time with slightly higher values than for the control network (no fitness considered), a drastic effect was noted for the community with smaller fitness.     

Lie Acceptability: A Construct and Measure

People likely hold different opinions about deceptive communication. Lie acceptability refers to an individual's attitude about deceptive communication. A self-report measure of lie acceptability was updated and refined, and preliminary data (N = 312) consistent with validity were reported. CFA indicated acceptable fit to the a priori unidimensional model. As anticipated, the lie acceptability scale was positively related to narcissism and negatively associated with religiosity. The scale also predicted likelihood of use ratings of equivocal messages, deceptive omissions, and outright lies. An anticipated sex difference, however, was not replicated. The potential utility of the scale in communication research is discussed.     

Constitutive Pluralism of Chemistry: Thought Planning, Curriculum, Epistemological and Didactic Orientations

Maybe the most difficult aspect of thinking about chemistry arises from the fact that chemistry isn’t an homogeneous subject. As a central science, it draws on a range of philosophical perspectives which in turn can result in different cognitive, learning and teaching styles in chemical education. This idea, apparently non-controversial, needs to be validated by more research. Without assuming this constitutive pluralism, describing it, and determining it, it becomes difficult to think of curricular goals and content. Thus, if we intend to improve the teaching of chemistry it is necessary, first, to assume explicitly this constitutive pluralism, then to map it in order to find the guiding principles: first for the mind (thought process), then for the curriculum and finally for the teaching, in such a way that it is as close as possible to the chemical way of operating and thinking. This is the aim of this paper. It reports the authors’ experiences in drafting structural ideas and planning for the subject “didactic of chemistry” based on the philosophy of chemistry at the University of Porto in Portugal.     

Developing Elementary Teachers’ Understandings of Hedges and Personal Pronouns in Inquiry-Based Science Classroom Discourse

This study examined the effectiveness of introducing elementary teachers to the scholarly literature on personal pronouns and hedges in classroom discourse, a professional development strategy adopted during a summer institute to enhance teachers’ social understanding (i.e., their understanding of the social functions of language in science discussions). Teachers became aware of how hedges can be employed to remain neutral toward students’ oral contributions to classroom discussions, invite students to share their opinions and articulate their own ideas, and motivate students to inquire. Teachers recognized that the combined use of I and you can render their feedback authoritative, you can shift the focus from the investigation to students’ competence, and we can lead to authority loss. It is argued that explicitness, reflectivity, and contextualization are essential features of professional development programs aimed at improving teachers’ understandings of the social dimension of inquiry-based science classrooms and preparing teachers to engage in inquiry-based teacher–student interactions.     

Botany and environmental education in elementary school in Brazil: articulating knowledge,values, and procedures

Abstract

The increasing urbanization and alienation from nature reduce children’s opportunities to interact with plants and challenge teachers to devise educational practices that contribute to learning botany. This study presents the results of activities developed in a Brazilian school through explorations, drawings, dried and pressed specimens, and semi-structured interviews. The data were evaluated using mixed methods analysis. Leaves were the structure that was most frequently drawn by 1st- and 2nd-year students, followed by stems. Among students in their 3rd, 4th, and 5th years, more emphasis was on flowers and their detailed morphological structures. The 1st- and 2nd-year students included non-living elements and the surrounding environment in their drawings, whereas the older students focused on the plant itself. These particularities point to methods of teaching botany in context and link students’ specific knowledge to values and practices that contribute to an environmental education that aims to minimize the utilitarian view of nature and move towards a view of human beings as integrated and interdependent with other living and non-living elements.     

A multilevel hypernetworks approach to capture meso-level synchronisation processes in football

ABSTRACT

Understanding team behaviours in sports performance requires understanding the interdependencies established between their levels of complexity (micro-meso-macro). Previously, most studies examined interactions emerging at micro- and macro-levels, thus neglecting those emerging at a meso-level (reveals connections between player and team levels, depicted by the emergence of coordination in specific sub-groups of players–simplices during performance). We addressed this issue using the multilevel hypernetworks approach, adopting a cluster-phase method, to record player-simplice synchronies in two performance conditions where the number, size and location of goals were manipulated (first-condition: 6 × 6 + 4 mini-goals; second-condition: Gk + 6 × 6 + Gk). We investigated meso-level coordination tendencies, as a function of ball-possession (attacking/defending), field-direction (longitudinal/lateral) and teams (Team A/Team B). Generally, large synergistic relations and more stable patterns were observed in the longitudinal direction of the field than the lateral direction for both teams, and for both game phases in the first condition. The second condition displayed higher synchronies and more stable patterns in the lateral direction than the longitudinal plane for both teams, and for both game phases. Results suggest: (i) usefulness of hypernetworks in assessing synchronisation of teams at a meso-level; (ii) coaches may consider manipulating these task constraints to develop levels of local synchronies within teams.     

From professional development to classroom instruction: addressing issues related to science inquiry discourse

In this rejoinder, I first provide a more detailed account of the discourse-focused professional development activities facilitated as part of the SMIT’N program, specifically addressing issues raised by van Zee with regard to the institute’s overall format, goals and development strategies. Next, I resort to Peter Medawar’s metaphorical view of inquiry as scientific storytelling to reflect about Bencze’s expressed opposition to “politely guided quasi-inductive science inquiry instruction” and highlight the need for science educators to give more careful consideration to oral classroom discourse. I then conclude by describing how guided science inquiry teaching can be conceived in terms of the theoretical notion of negative politeness.