134 research outputs found

    Optimal control of shock wave attenuation in single - and two-phase flow with application to ignition overpressure in launch vehicles

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    NASA and private launch providers have a need to understand and control ignition overpressure blast waves that are generated by a solid grain rocket during ignition. Research in accurate computational fluid dynamics prediction of the launch environment is underway. A clearer picture is emerging from empirical data which more precisely categorizes all the dissipative mechanisms present in droplet-shock interactions. In this dissertation, water droplets and their effects due to vaporization are represented as a control action and two new optimal control problems are formulated concerning unsteady shock wave attenuation. A single-phase control problem is formulated by representing the effect of droplet vaporization as an energy sink on the right hand side of the unsteady Euler Equations in one dimension. Results for the optimal distribution of equivalent mass of water vaporized for a given level of attenuation are presented. A two-phase control problem consists of solving for the initial optimal water droplet distribution. Results are presented for constrained and unconstrained water volume fraction distributions over increasing levels of attenuation. New adjoint-based algorithms were constructed which leave the final time free and satisfy all first order necessary conditions as well as avoid taking a variation at the shock front.http://archive.org/details/optimalcontrolof1094510658Approved for public release; distribution is unlimited

    Bridging the gap between high and low performing pupils through performance learning online analysis and curricula

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    Metacognition is a neglected area of investment in formal education and in teachers’ professional development. This paper presents an approach and tools, created by a London-based company called Performance Learning Education (PL), for supporting front-line teachers and learners in developing metacognitive competencies. An iterative process adopted by PL in developing and validating its approach is presented, demonstrating its value to real educational practices, it’s research potential in the area of metacognition, and its AI readiness, especially in relation to modelling learners’ non-cognitive competencies

    Rationality as a Goal of Education

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    Abstract Those who believe education should involve more than learning facts often stress either (a) development or (b) thinking skills. A focus on development as a goal of education typically entails a conception of knowledge as organismic, holistic, and internally generated. In contrast, thinking skills programs commonly assume a mechanistic, reductionist perspective in which good thinking consists of some finite number of directly teachable skills. A conception of rationality as a goal of education is proposed that incorporates the complementary strengths and avoids the limitations of the developmental and thinking skills approaches. Rationality is defined as the self-reflective, intentional, and appropriate coordination and use of genuine reasons in generating and justifying beliefs and behavior. Philosophically, rationality is a justifiable goal of education, not only because it is a means to worthwhile ends but because it is an important end in itself and because it can be promoted via non-indoctrinative means. A psychological account of progressive rationality is provided that postulates continuing multiple interactions of (a) domain-specific developmental stages, (b) the learning of specific thinking skills, and (c) content-specific knowledge. Suggestions are made for fostering rationality at various educational levels. Finally, it is argued that the proposed conception of rationality as a goal of education complements and clarifies a variety of other educational goals

    Development of intuitive rules: Evaluating the application of the dual-system framework to understanding children's intuitive reasoning

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    This is an author-created version of this article. The original source of publication is Psychon Bull Rev. 2006 Dec;13(6):935-53 The final publication is available at www.springerlink.com Published version: http://dx.doi.org/10.3758/BF0321390

    Dispositional optimism as a correlate of decision-making styles in adolescence

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    Despite the numerous psychological areas in which optimism has been studied, including career planning, only a small amount of research has been done to investigate the relationship between optimism and decision-making styles. Consequently, we have investigated the role of dispositional optimism as a correlate of different decision-making styles, in particular, positive for effective styles and negative for ineffective ones (doubtfulness, procrastination, and delegation). Data were gathered through questionnaires administered to 803 Italian adolescents in their last 2 years of high schools with different fields of study, each at the beginning stages of planning for their professional future. A paper questionnaire was completed containing measures of dispositional optimism and career-related decision styles, during a vocational guidance intervention conducted at school. Data were analyzed using stepwise multiple regression. Results supported the proposed model by showing optimism to be a strong correlate of decision-making styles, thereby offering important intervention guidelines aimed at modifying unrealistically negative expectations regarding their future and helping students learn adaptive decision-making skills

    Beyond motivation: Job and work design for development, health, ambidexterity, and more

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    Much research shows it is possible to design motivating work, which has positive consequences for individuals and their organizations. This article reviews research that adopts this motivational perspective on work design, and it emphasizes that it is important to continue to refine motivational theories. In light of continued large numbers of poor-quality jobs, attention must also be given to influencing practice and policy to promote the effective implementation of enriched work designs. Nevertheless, current and future work-based challenges mean that designing work for motivation is necessary but insufficient. This review argues that work design can be a powerful vehicle for learning and development, for maintaining and enhancing employees' physical and mental health, and for achieving control and flexibility simultaneously (for example, in the form of ambidexterity); all these outcomes are important given the challenges in today's workplaces. The review concludes by suggesting methodological directions
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