1,187 research outputs found

    The Central Role of Noise in Evaluating Interventions that Use Test Scores to Rank Schools

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    Several countries have implemented programs that use test scores to rank schools, and to reward or penalize them based on their students' average performance. Recently, Kane and Staiger (2002) have warned that imprecision in the measurement of school-level test scores could impede these efforts. There is little evidence, however, on how seriously noise hinders the evaluation of the impact of these interventions. We examine these issues in the context of Chile's P-900 program a country-wide intervention in which resources were allocated based on cutoffs in schools' mean test scores. We show that transitory noise in average scores and mean reversion lead conventional estimation approaches to greatly overstate the impacts of such programs. We then show how a regression discontinuity design that utilizes the discrete nature of the selection rule can be used to control for reversion biases. While the RD analysis provides convincing evidence that the P-900 program had significant effects on test score gains, these effects are much smaller than is widely believed.

    eMoto - Affectively Involving both Body and Mind

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    It is known that emotions are experienced by both body and mind. Oftentimes, emotions are evoked by sub-symbolic stimuli, such as colors, shapes, gestures, or music. We have built eMoto, a mobile service for sending affective mes-sages to others, with the explicit aim of addressing such sensing. Through combining affective gestures for input with affective expressions that make use of colors, shapes and animations for the background of messages, the interac-tion pulls the user into an embodied ‘affective loop’. We present a user study of eMoto where 12 out of 18 subjects got both physically and emotionally involved in the interac-tion. The study also shows that the designed ‘openness’ and ambiguity of the expressions, was appreciated and under-stood by our subjects

    Extrapolation of Multiplicity distribution in p+p(\bar(p)) collisions to LHC energies

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    The multiplicity (N_ch) and pseudorapidity distribution (dN_ch/d\eta) of primary charged particles in p+p collisions at Large Hadron Collider (LHC) energies of \sqrt(s) = 10 and 14 TeV are obtained from extrapolation of existing measurements at lower \sqrt(s). These distributions are then compared to calculations from PYTHIA and PHOJET models. The existing \sqrt(s) measurements are unable to distinguish between a logarithmic and power law dependence of the average charged particle multiplicity () on \sqrt(s), and their extrapolation to energies accessible at LHC give very different values. Assuming a reasonably good description of inclusive charged particle multiplicity distributions by Negative Binomial Distributions (NBD) at lower \sqrt(s) to hold for LHC energies, we observe that the logarithmic \sqrt(s) dependence of are favored by the models at midrapidity. The dN_ch/d\eta versus \eta for the existing measurements are found to be reasonably well described by a function with three parameters which accounts for the basic features of the distribution, height at midrapidity, central rapidity plateau and the higher rapidity fall-off. Extrapolation of these parameters as a function of \sqrt(s) is used to predict the pseudorapidity distributions of charged particles at LHC energies. dN_ch/d\eta calculations from PYTHIA and PHOJET models are found to be lower compared to those obtained from the extrapolated dN_ch/d\eta versus \eta distributions for a broad \eta range.Comment: 11 pages and 13 figures. Substantially revised and accepted for publication in Journal of Physics

    A user-centred approach to affective interaction

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    We have built eMoto, a mobile service for sending and receiving affective messages, with the explicit aim of addressing the inner experience of emotions. eMoto is a designed artifact that carries emotional experiences only achieved through interaction. Following on the theories of embodiment, we argue emotional experiences can not be design in only design for. eMoto is the result of a user-centered design approach, realized through a set of initial brain-storming methods, a persona, a Laban-analysis of body language and a two-tiered evaluation method. eMoto is not a system that could have been designed from theory only, but require an iterative engagement with end-users, however, in combination with theoretical work. More specifically, we will show how we have managed to design an ambiguous and open system that allows for users’ emotional engagement

    Open innovation research, management and practice

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    The concept of open innovation has become increasingly popular in the management and policy literature on technology and innovation. However, despite the large volume of empirical work, many of the prescriptions being proposed are fairly general and not specific to particular contexts and contingencies. The proponents of open innovation are universally positive but research suggests that the specific mechanisms and outcomes of open innovation models are very sensitive to context and contingency. This is not surprising because the open or closed nature of innovation is historically contingent and does not entail a simple shift from closed to open as often suggested in the literature. Research has shown that patterns of innovation differ fundamentally by sector, firm and strategy. Therefore, there is a need to examine the mechanisms that help to generate successful open innovation. In this book, the authors contribute to a shift in the debate from potentially misleading general prescriptions, and provide conceptual and empirical insights into the precise mechanisms and potential limitations of open innovation research and management practice

    A Foundation for Emotional Expressivity

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    To express emotions to others in mobile text messaging in our view require designs that can both capture some of the ambiguity and subtleness that characterizes emotional interaction and keep the media specific qualities. Through the use of a body movement analysis and a dimensional model of emotion experiences, we arrived at a design for a mobile messaging service, eMoto. The service makes use of the sub-symbolic expressions; colors, shapes and animations, for expressing emotions in an open-ended way. Here we present the design process and a user study of those expressions, where the results show that the use of these sub-symbolic expressions can work as a foundation to use as a creative tool, but still allowing for the communication to be situated. The inspiration taken from body movements proved to be very useful as a design input. It was also reflected in the way our subjects described the expressions

    Conductive Carbon Materials from the Hydrothermal Carbonization of Vineyard Residues for the Application in Electrochemical Double-Layer Capacitors (EDLCs) and Direct Carbon Fuel Cells (DCFCs)

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    This study investigates the production of bio-based carbon materials for energy storage and conversion devices based on two different vineyard residues (pruning, pomace) and cellulose as a model biomass. Three different char categories were produced via pyrolysis at 900 °C for 2 h (biochars, BC), hydrothermal carbonization (HTC) (at 220, 240 or 260 °C) with different reaction times (60, 120 or 300 min) (hydrochars, HC), or HTC plus pyrolysis (pyrolyzed hydrochars, PHC). Physicochemical, structural, and electrical properties of the chars were assessed by elemental and proximate analysis, gas adsorption surface analysis with N2 and CO2, compression ratio, bulk density, and electrical conductivity (EC) measurements. Thermogravimetric analysis allowed conclusions to be made about the thermochemical conversion processes. Taking into consideration the required material properties for the application in electrochemical double-layer capacitors (EDLC) or in a direct carbon fuel cell (DCFC), the suitability of the obtained materials for each application is discussed. Promising materials with surface areas up to 711 m2 g−1 and presence of microporosity have been produced. It is shown that HTC plus pyrolysis from cellulose and pruning leads to better properties regarding aromatic carbon structures, carbon content (>90 wt.%), EC (up to 179 S m−1), and porosity compared to one-step treatments, resulting in suitable materials for an EDLC application. The one-step pyrolysis process and the resulting chars with lower carbon contents and low EC values between 51 and 56 S m−1 are preferred for DCFC applications. To conclude, biomass potentials can be exploited by producing tailored biomass-derived carbon materials via different carbonization processes for a wide range of applications in the field of energy storage and conversion
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