Harmonic oscillator utilizing double-fold integral, traditional and second-order sliding mode control

To stabilize both amplitude and frequency of the second-order harmonic oscillator double-fold sliding mode control is employed. The first, integral sliding mode control, is used to compensate for the disturbance/uncertainty, which is unmatched by the second control. The second sliding mode control is designed to achieve the stabilization of the harmonic oscillator system while the system is in the integral sliding mode. The first (integral) and second sliding mode controls are implemented in both formats: traditional sliding mode control that requires high-frequency oscillating control action and second-order sliding mode (super-twisting) control that is continuous and provides for the higher accuracy of stabilization. It is shown that the output of the double-fold sliding mode controlled second-order harmonic oscillator is robust to bounded disturbances and model parameter uncertainties. Computer simulations are performed to manifest the theoretical analysis.     

Functional impact of emotions on athletic performance: comparing the IZOF model and the directional perception approach

The aim of this study was to examine the impact of emotions on athletic performance within the frameworks of the Individual Zones of Optimal Functioning (IZOF) model and the directional perception approach. Intensity, functional impact, and hedonic tone of trait and state anxiety, self-confidence, idiosyncratic emotions, and bodily symptoms were assessed in high-level Italian swimmers and track and field athletes (N = 56). Three standards of performance (poor, average, and good), derived from retrospective self-ratings across one to three competitions (a total of 90 observations), were used as independent variables in the analysis of variance of intensity, intra-individual, and direction scores of anxiety, self-confidence, idiosyncratic emotions, and bodily symptoms. Subsequently, intra-individual scores were categorized as near to or distant from optimal/dysfunctional zones and entered as the independent variable in the analysis of direction scores. The results provided support for the predictions stemming from both the IZOF model and the directional approach, as well as help in interpreting direction of anxiety and other idiosyncratic emotions within the IZOF framework. Athletes tended to perceive emotional levels approximating an individual's optimal zone as facilitative-pleasant, and emotional levels approximating an individual's dysfunctional zone as debilitative-unpleasant.     

An exact formula for the maximum VCO sweep rate of a PLL

In many phase-locked loop (PLL) applications, the natural pull-in mechanism is too slow and unreliable, and it must be accelerated. By adding an externally-generated ramp to its control voltage input, the PLL voltage controlled oscillator (VCO) frequency can be swept towards the input reference frequency in an attempt to speed up the pull-in process. This popular acquisition aid has a significant limitation when it is used in a second-order, Type II PLL. If the applied ramp voltage has a slope magnitude greater than (alternatively, less than) some value R_m, the PLL state can (alternatively, cannot) sweep past the desired lock point, resulting in a phase lock failure (alternatively, success). In general, the maximum sweep rate magnitude R_m can be computed by using a numerical integration-and-search procedure that is described in the PLL literature. A special case exists for a second-order, Type II PLL that incorporates a triangular-characteristic phase detector (with logic-level binary input signals). For this case, it is possible to develop an exact, closed-form expression for R_m, the main result of this paper. For a range of loop parameters most often used in applications, R_m values are computed by using the exact formula, and these are used in two ways. First, they are used to validate the previously-mentioned numerical integration-and-search procedure. Second, they are compared to maximum sweep rate values computed for a PLL that utilizes a sinusoidal phase detector to show that the triangular-phase-detector PLL can be swept significantly faster than the sinusoidal-phase-detector loop.     

Decentralized continuous MRAC with local asymptotic sliding modes of nonlinear delayed interconnected systems

In this contribution, we develop continuous completely decentralized state-feedback adaptive controllers with sliding mode for a class of large-scale interconnected systems with nonlinear interconnections with unknown time-varying state delays. The novel contribution of this paper is that asymptotically exact tracking within the framework of completely decentralized direct continuous adaptive control is possible also for a class of nonlinear plants with matched interconnections and disturbances.     

Values, objectivity and credibility of scientists in a contentious natural resource debate

In contentious natural resource debates, the credibility of scientists is at risk. In this case study, citizens in contending communities and scientists in a forest management controversy constructed the scientists' credibility differently. Shared values and views of the nature of science and objectivity were primary factors for constructing scientists' credibility. Citizens who expected value-free, objective scientists to authenticate their knowledge were concerned about how the values of scientists on the opposite side affected research framing. Citizens who emphasized limited objectivity were less skeptical of scientists. Scientists acknowledged their values but defended their credibility in terms of professional standards, balance and resource constraints. In short, scientists' credibility is relative because each individual has unique values and views of the nature of science and objectivity. Through a collaborative policymaking process, citizens and scientists should develop shared values and visions to reconstruct a temporary, intersubjective sense of credibility.     

Exploring physically active play in the early childhood curriculum from a complexity thinking perspective

This paper conceptualizes the teaching and learning of physically active play (PAP) in the early childhood curriculum. The conceptualization emerges from ‘doing complexivist bricolage’ and draws on complexity thinking features and concepts to position teaching and learning in PAP as children and teachers together exploring three different and coupled facets: fundamental movement patterns, group movement activities and group games. The three facets are different and coupled to highlight that they can be viewed as simultaneously separate and inseparable. This allows us to make sense of each facet and remind us that they are mutually influencing. Exploring fundamental movement patterns means focusing on exploring patterns and variations associated with one or more particular movement skills and balancing skills, and doing so in the context of individual activities, group movement activities or games. Exploring group movement activities involve children moving with their bodies as they engage in rhymes, songs and stories, thereby enabling children to develop both fundamental movement skills and literacy skills. Engaging in group games focuses on supporting children to learn the nature of games as socially constructed activities with some explicit rules agreed upon by players. I position teaching and learning as acts of joint exploration that embrace diverse learners (children and teachers) and different learning outcomes for individuals. In this joint exploration, the teacher plays two important roles: (1) fostering children’s and their own confidence and competence in PAP and (2) creating conditions that simultaneously constrain and enable as they follow, generate and sustain children’s interests in their explorations together. This approach enables teachers to respond to children’s interests and co-create learning situations with children in ways that are emergent and meaningful to all. When used in conjunction with mandated curriculum frameworks, it can open up possibilities for curriculum, teaching and learning for children and teachers.     

Regional lifelong learning policies and the social vulnerability of young adults in Girona and Vienna

ABSTRACT

This article explores the interface between lifelong learning policies and the definition of social vulnerability of young adults in two regions located within the European Union. Girona comprises a constellation of small towns with important industry, service and hospitality sectors. Vienna is a global city where many key international operators are based and employ a large number of highly qualified professionals. The article explores to what extent the meta-governance and the ‘causal narratives’ of lifelong learning policies contribute towards shaping the prevailing images of youth vulnerability in these regions. In Girona, bureaucratic governance patterns lifelong learning policies, which strongly rely on the potential of career guidance to encourage the youth to undertake further education. Correspondingly, policy designs and professional discourses emphasise that the beneficiaries previously failed at school. In Vienna, authorities govern lifelong learning by means of both bureaucracy and complex networks of employers and non-profit organisations. The ‘causal narrative’ of the policies straightforwardly claims that all youth must have an experience with employment, whether in apprenticeships or in transitional workshops that emulate real jobs. There, policies portray beneficiaries according to their capacity to undertake and finish apprenticeships.     

Academic Dishonesty in the Middle East: Individual and Contextual Factors

Little work has been done on academic dishonesty in the Middle East. This research investigates the nature of the relationship between contextual factors and academic dishonesty using a sample from three private universities in Lebanon, and compares the results to a sample from seven large universities in the US. Using the basic model of McCabe et al. (Research in Higher Education 43(3):357–378, 2002), we found additional evidence for the strong role perception of peers’ behavior plays in understanding student decisions concerning academic integrity. Cross cultural comparisons of attitudes, beliefs, and behaviors regarding academic dishonesty were pivotal in this research. Our results support the view that Lebanese university students are strongly influenced by the norms of the collectivist society in which they are raised as compared to the more individualistic society found in the United States.