372 research outputs found

    Effect of Changing the Vocal Tract Shape on the Sound Production of the Recorder: An Experimental and Theoretical Study

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    Changing the vocal tract shape is one of the techniques which can be used by the players of wind instruments to modify the quality of the sound. It has been intensely studied in the case of reed instruments but has received only little attention in the case of air-jet instruments. This paper presents a first study focused on changes in the vocal tract shape in recorder playing techniques. Measurements carried out with recorder players allow to identify techniques involving changes of the mouth shape as well as consequences on the sound. A second experiment performed in laboratory mimics the coupling with the vocal tract on an artificial mouth. The phase of the transfer function between the instrument and the mouth of the player is identified to be the relevant parameter of the coupling. It is shown to have consequences on the spectral content in terms of energy distribution among the even and odd harmonics, as well as on the stability of the first two oscillating regimes. The results gathered from the two experiments allow to develop a simplified model of sound production including the effect of changing the vocal tract shape. It is based on the modification of the jet instabilities due to the pulsating emerging jet. Two kinds of instabilities, symmetric and anti-symmetric, with respect to the stream axis, are controlled by the coupling with the vocal tract and the acoustic oscillation within the pipe, respectively. The symmetry properties of the flow are mapped on the temporal formulation of the source term, predicting a change in the even / odd harmonics energy distribution. The predictions are in qualitative agreement with the experimental observations

    Autonomous Navigation and Security: A 13000h/3000km Case Study

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    This paper presents the design of an autonomous mobile platform and its security system. The MB835 mobile platform has been adopted for RoboX, a fully autonomous tour guide robot. In 2002, 11 of these tour guides have served the Robotics exhibition at Expo.02 (Swiss National Exhibition) from May 15 to October 20. This project has been conjointly conducted by the Autonomous Systems Lab, Swiss Federal Institute of Technology Lausanne (EPFL) and BlueBotics SA the spin-off company of the lab, which has produced the robots. The goal was to maximize the autonomy and mobility of the platform while ensuring high performance, robustness and security. The paper presents the platform, its navigation and security, which resulted in the ANT product (Autonomous Navigation Technology) and the results of the Robotics exhibition as empirical validation of the whole system

    The win/profit maximization debate: Strategic adaptations as the answer?

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    Purpose The purpose of this paper is twofold. First, to highlight the heterogeneity of the organizational aims within the professional football teams in Ligue 1. Second, to understand why some teams swing from a win orientation towards a soft budget constraint from year to year, and vice versa. Design/methodology/approach Financial data from annual reports for the period 2005/2015 was collected for the 35 Ligue 1 clubs. To define the degree of compliance with the intended strategy for those clubs, an efficiency analysis was conducted thanks to the data envelopment analysis method. This measure of performance was supplemented with the identification of productivity and demand shocks to identify whether clubs suffered from such shock or changed their strategy. It enables to precise the nature of the evolution in the utility function, with regards to the gap between expectation and actual performance. Findings The paper suggests that a team can switch from one orientation to another from year to year due to the uncertain nature of the sports industry. The club director’s utility function could also be maximized under inter temporal budget function in order to adjust the weight between win and profit according to the opportunities in the environment. Originality/value The paper sheds new light on the win/profit maximization. The theoretical model provides an assessment of the weight between win and profit in Ligue 1 and then identifies a new explanation for persistent losses in the sports industry

    The SDSS-III APOGEE Radial Velocity Survey of M dwarfs I: Description of Survey and Science Goals

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    We are carrying out a large ancillary program with the SDSS-III, using the fiber-fed multi-object NIR APOGEE spectrograph, to obtain high-resolution H-band spectra of more than 1200 M dwarfs. These observations are used to measure spectroscopic rotational velocities, radial velocities, physical stellar parameters, and variability of the target stars. Here, we describe the target selection for this survey and results from the first year of scientific observations based on spectra that is publicly available in the SDSS-III DR10 data release. As part of this paper we present RVs and vsini of over 200 M dwarfs, with a vsini precision of ~2 km/s and a measurement floor at vsini = 4 km/s. This survey significantly increases the number of M dwarfs studied for vsini and RV variability (at ~100-200 m/s), and will advance the target selection for planned RV and photometric searches for low mass exoplanets around M dwarfs, such as HPF, CARMENES, and TESS. Multiple epochs of radial velocity observations enable us to identify short period binaries, and AO imaging of a subset of stars enables the detection of possible stellar companions at larger separations. The high-resolution H-band APOGEE spectra provide the opportunity to measure physical stellar parameters such as effective temperatures and metallicities for many of these stars. At the culmination of this survey, we will have obtained multi-epoch spectra and RVs for over 1400 stars spanning spectral types of M0-L0, providing the largest set of NIR M dwarf spectra at high resolution, and more than doubling the number of known spectroscopic vsini values for M dwarfs. Furthermore, by modeling telluric lines to correct for small instrumental radial velocity shifts, we hope to achieve a relative velocity precision floor of 50 m/s for bright M dwarfs. We present preliminary results of this telluric modeling technique in this paper.Comment: Submitted to Astronomical Journa

    Design and System Integration for the Expo.02 Robot

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    This paper presents the genesis of the Expo.02 robot. RoboX the tour guide robot has been built from the scratch for this project based on the experience of the Autonomous Systems Lab. The production of 11 of those machines has been guaranteed by a spin-off of the lab: BlueBotics SA. The goal was to maximize the autonomy and interactivity of the mobile platform while ensuring high robustness, reliability and performance. The result is an interactive moving machine which can operate in human environments and interact by seeing humans, talking to and looking at them, showing icons and asking them to answer its questions. Here, the complete design of mechanics, electronics and software is presented first, followed by the statistics about the first two month of operation

    Designing a Secure and Robust Mobile Interacting Robot for the Long Term

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    This paper presents the genesis of RoboX. This tour guide robot has been built from the scratch based on the experience of the Autonomous Systems Lab. The production of 11 of those machines has been realized by a spin-off of the lab: BlueBotics SA. The goal was to maximize the autonomy and interactivity of the mobile platform while ensuring high robustness, security and performance. The result is an interactive moving machine which can operate in human environments and interacts by seeing humans, talking to and looking at them, showing icons and asking them to answer its questions. The complete design of mechanics, electronics and software is presented in the first part. Then, as extraordinary test bed, the Robotics exhibition at Expo.02 (Swiss National Exhibition) permits to establish meaningful statistics over 5 months (from May 15 to October 20, 2002) with up to 11 robots operating at the same time

    Target Selection for the Apache Point Observatory Galactic Evolution Experiment (APOGEE)

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    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution infrared spectroscopic survey spanning all Galactic environments (i.e., bulge, disk, and halo), with the principal goal of constraining dynamical and chemical evolution models of the Milky Way. APOGEE takes advantage of the reduced effects of extinction at infrared wavelengths to observe the inner Galaxy and bulge at an unprecedented level of detail. The survey's broad spatial and wavelength coverage enables users of APOGEE data to address numerous Galactic structure and stellar populations issues. In this paper we describe the APOGEE targeting scheme and document its various target classes to provide the necessary background and reference information to analyze samples of APOGEE data with awareness of the imposed selection criteria and resulting sample properties. APOGEE's primary sample consists of ~100,000 red giant stars, selected to minimize observational biases in age and metallicity. We present the methodology and considerations that drive the selection of this sample and evaluate the accuracy, efficiency, and caveats of the selection and sampling algorithms. We also describe additional target classes that contribute to the APOGEE sample, including numerous ancillary science programs, and we outline the targeting data that will be included in the public data releases.Comment: Accepted to AJ. 31 pages, 11 figure
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