The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Pierre Moretto - One of the best experts on this subject based on the ideXlab platform.
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Walking Dynamic Similarity induced by a combination of Froude and Strouhal dimensionless numbers: Modela-w
Gait and Posture, 2015Co-Authors: David Villeger, Antony Costes, Bruno Watier, Pierre MorettoAbstract:The aim of this study was to assess the accuracy of a new dimensionless number associating Froude (Nfr) and Strouhal (Str) called Modela-w to induce walking Dynamic Similarity among humans of different sizes. Nineteen subjects walked in three experimental conditions: (i) constant speed, (ii) similar speed (Nfr) and (iii) similar speed and similar step frequency (Modela-w). The Dynamic Similarity was evaluated from scale factors computed with anthropometric, temporal, kinematic and kinetic data and from the decrease of the variability of the parameters expressed in their dimensionless form. Over a total of 36 Dynamic parameters, Dynamic Similarity from scale factors was met for 11 (mean r = 0.51), 22 (mean r = 0.52) and 30 (mean r = 0.69) parameters in the first, the second and the third experimental conditions, respectively. Modela-w also reduced the variability of the dimensionless preceding parameters compared to the other experimental conditions. This study shows that the combination of Nfr and Str called Modela-w ensures Dynamic Similarity between different-sized subjects and allows scientists to impose similar experimental conditions removing all anthropometric effects.
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Modela-r as a Froude and Strouhal dimensionless numbers combination for Dynamic Similarity in running
Journal of Biomechanics, 2014Co-Authors: David Villeger, Antony Costes, Bruno Watier, Pierre MorettoAbstract:The aim of this study was to test the hypothesis t hat running at fixed fractions of Froude (Nfr) and Strouhal (Str) dimensionless numbe rs combinations induce Dynamic Similarity between humans of different sizes. Ninet een subjects ran in three experimental conditions, i) constant speed, ii) similar speed (N fr) and iii) similar speed and similar step frequency (Nfr and Str combination). In addition to anthropometric data, temporal, kinematic and kinetic parameters were assessed at each stage to measure Dynamic Similarity informed by dimensional scale factors and by the decrease of dimensionless mechanical parameter variability. Over a total of 54 Dynamic parameters, Dynamic Similarity from scale factors was met for 16 (mean r = 0.51), 32 (mean r = 0.49) and 52 (mean r = 0.60) parameters in the first, the second and the third experimental conditions, r espectively. The variability of the dimensionless preceding parameters was lower in the third condition than in the others. This study shows that the combination of Nfr and Str, computed from the dimensionless energy ratio at the center of gravity (Modela-r) ensures d ynamic Similarity between different-sized subjects. The relevance of using similar experiment al conditions to compare mechanical dimensionless parameters is also proved and will hi ghlight the study of running techniques, or equipment, and will allow the identification of abnormal and pathogenic running patterns. Modela-r may be adapted to study other abilities requiring b ounces in human or animal locomotion or to conduct investigations in comparat ive biomechanics.
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Dynamic Similarity during human running: about Froude and Strouhal dimensionless numbers.
Journal of biomechanics, 2009Co-Authors: Nicolas Delattre, Mario A. Lafortune, Pierre MorettoAbstract:Abstract Dynamic Similarity is a widely used concept in the fluid mechanics field, and consists in placing two different-sized systems in equivalent experimental conditions. This enables removal of the effects of size and prediction of the behavior of a full size system from a scale model. The aim of this study was to test whether the Froude number (Nfr) or the Strouhal number (Str) could be used as a criterion for Dynamic Similarity during running. Fifteen male subjects ran barefoot on a runway in three experimental conditions (i) all subjects ran at the same speed V=3.5 m s−1; (ii) the speed was determined from Nfr; (iii) the stride frequency was determined from Str. Antero-posterior (Fy) and vertical (Fz) ground reaction force components were assessed. The Similarity between the subjects was analysed from scale factor sets computed from anthropometric and kinetic data. The use of Str implied strong inter-subject Similarity for temporal parameters (mean r=0.96, time to Fz peak, time to Fy braking peak, Fy zero fore–aft shear, time to Fy propulsive peak) while Nfr induced fewer and lower similarities (mean r=0.75, Fy zero fore–aft shear, time to Fy propulsive peak, Fy braking impulse) that only concerned antero-posterior parameters. This study brought experimental evidence that neither Nfr nor Str were sufficient for Dynamic Similarity during running, but that each of them made its own contribution. These findings suggested that the concomitant use of Nfr and Str should be assessed to induce inter-subject Dynamic Similarity during running.
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A new dimensionless number for Dynamic Similarity during running (P250)
Engineering of Sport 7 Vol 2, 2008Co-Authors: Nicolas Delattre, Pierre MorettoAbstract:This abstract aims to present the assessment of a new dimension less number for the study of Dynamic Similarity (DS) during running by using a computer simulation. Previous studies on walking (Bisiaux et al., 2003, Moretto er al., 2007) induced DS between subjects and reported a decrease of data variability by using the Froude number, a dimensionless number founded on mechanical energy transfers Occurring during walking. Delattre et al. (2007) reported that the use of the Strouhal number (another dimensionless number based on the spring-mass model (SMM) for the mechanics of running) enabled to induce DS between running subjects. However it seems to LIS that this approach could be refined. As it has been made to highlight Nfr from the inverted pendulum model, we proposed to consider mechanical energy transfers occurring at the centre of gravity of a simulated SMM. We built two different-sized and proportional SMM and computed E-P (potential energy), E-K (kinetic energy), E-E (elastic energy). Results showed that the ratio R=(E-P+E-K)/E(E)was constant and reached identical value for both SMM (4.1 +/- 0.72 and 4.1 +/- 0.71) from 30 to 70% of the Simulation time. Taking the limits of the simulation into account, we conclude that the dimensionless number R Could theoretically be used to induce DS during running. Future investigation has to assess R for DS in vivo.
David Hawking - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Similarity aware inverted indexing for real time entity resolution
Knowledge Discovery and Data Mining, 2013Co-Authors: Banda Ramadan, Peter Christen, Huizhi Liang, Ross W Gayler, David HawkingAbstract:Entity resolution is the process of identifying groups of records in a single or multiple data sources that represent the same real-world entity. It is an important tool in data de-duplication, in linking records across databases, and in matching query records against a database of existing entities. Most existing entity resolution techniques complete the resolution process offline and on static databases. However, real-world databases are often Dynamic, and increasingly organizations need to resolve entities in real-time. Thus, there is a need for new techniques that facilitate working with Dynamic databases in real-time. In this paper, we propose a Dynamic Similarity-aware inverted indexing technique (DySimII) that meets these requirements. We also propose a frequency-filtered indexing technique where only the most frequent attribute values are indexed. We experimentally evaluate our techniques on a large real-world voter database. The results show that when the index size grows no appreciable increase is found in the average record insertion time (around 0.1 msec) and in the average query time (less than 0.1 sec). We also find that applying the frequency-filtered approach reduces the index size with only a slight drop in recall.
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PAKDD Workshops - Dynamic Similarity-Aware Inverted Indexing for Real-Time Entity Resolution
Lecture Notes in Computer Science, 2013Co-Authors: Banda Ramadan, Peter Christen, Huizhi Liang, Ross W Gayler, David HawkingAbstract:Entity resolution is the process of identifying groups of records in a single or multiple data sources that represent the same real-world entity. It is an important tool in data de-duplication, in linking records across databases, and in matching query records against a database of existing entities. Most existing entity resolution techniques complete the resolution process offline and on static databases. However, real-world databases are often Dynamic, and increasingly organizations need to resolve entities in real-time. Thus, there is a need for new techniques that facilitate working with Dynamic databases in real-time. In this paper, we propose a Dynamic Similarity-aware inverted indexing technique (DySimII) that meets these requirements. We also propose a frequency-filtered indexing technique where only the most frequent attribute values are indexed. We experimentally evaluate our techniques on a large real-world voter database. The results show that when the index size grows no appreciable increase is found in the average record insertion time (around 0.1 msec) and in the average query time (less than 0.1 sec). We also find that applying the frequency-filtered approach reduces the index size with only a slight drop in recall.
Nicolas Delattre - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Similarity during human running: about Froude and Strouhal dimensionless numbers.
Journal of biomechanics, 2009Co-Authors: Nicolas Delattre, Mario A. Lafortune, Pierre MorettoAbstract:Abstract Dynamic Similarity is a widely used concept in the fluid mechanics field, and consists in placing two different-sized systems in equivalent experimental conditions. This enables removal of the effects of size and prediction of the behavior of a full size system from a scale model. The aim of this study was to test whether the Froude number (Nfr) or the Strouhal number (Str) could be used as a criterion for Dynamic Similarity during running. Fifteen male subjects ran barefoot on a runway in three experimental conditions (i) all subjects ran at the same speed V=3.5 m s−1; (ii) the speed was determined from Nfr; (iii) the stride frequency was determined from Str. Antero-posterior (Fy) and vertical (Fz) ground reaction force components were assessed. The Similarity between the subjects was analysed from scale factor sets computed from anthropometric and kinetic data. The use of Str implied strong inter-subject Similarity for temporal parameters (mean r=0.96, time to Fz peak, time to Fy braking peak, Fy zero fore–aft shear, time to Fy propulsive peak) while Nfr induced fewer and lower similarities (mean r=0.75, Fy zero fore–aft shear, time to Fy propulsive peak, Fy braking impulse) that only concerned antero-posterior parameters. This study brought experimental evidence that neither Nfr nor Str were sufficient for Dynamic Similarity during running, but that each of them made its own contribution. These findings suggested that the concomitant use of Nfr and Str should be assessed to induce inter-subject Dynamic Similarity during running.
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A new dimensionless number for Dynamic Similarity during running (P250)
Engineering of Sport 7 Vol 2, 2008Co-Authors: Nicolas Delattre, Pierre MorettoAbstract:This abstract aims to present the assessment of a new dimension less number for the study of Dynamic Similarity (DS) during running by using a computer simulation. Previous studies on walking (Bisiaux et al., 2003, Moretto er al., 2007) induced DS between subjects and reported a decrease of data variability by using the Froude number, a dimensionless number founded on mechanical energy transfers Occurring during walking. Delattre et al. (2007) reported that the use of the Strouhal number (another dimensionless number based on the spring-mass model (SMM) for the mechanics of running) enabled to induce DS between running subjects. However it seems to LIS that this approach could be refined. As it has been made to highlight Nfr from the inverted pendulum model, we proposed to consider mechanical energy transfers occurring at the centre of gravity of a simulated SMM. We built two different-sized and proportional SMM and computed E-P (potential energy), E-K (kinetic energy), E-E (elastic energy). Results showed that the ratio R=(E-P+E-K)/E(E)was constant and reached identical value for both SMM (4.1 +/- 0.72 and 4.1 +/- 0.71) from 30 to 70% of the Simulation time. Taking the limits of the simulation into account, we conclude that the dimensionless number R Could theoretically be used to induce DS during running. Future investigation has to assess R for DS in vivo.
Krasimira Tsaneva-atanasova - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Similarity promotes interpersonal coordination in joint action
Journal of the Royal Society Interface, 2016Co-Authors: Piotr Słowiński, Chao Zhai, Francesco Alderisio, Robin N. Salesse, Mathieu Gueugnon, Ludovic Marin, Mario Di Bernardo, Benoit Bardy, Krasimira Tsaneva-atanasovaAbstract:Human movement has been studied for decades, and Dynamic laws of motion that are common to all humans have been derived. Yet, every individual moves differently from everyone else (faster/slower, harder/smoother, etc.). We propose here an index of such variability, namely an individual motor signature (IMS) able to capture the subtle differences in the way each of us moves. We show that the IMS of a person is time-invariant and that it significantly differs from those of other individuals. This allows us to quantify the Dynamic Similarity, a measure of rapport between Dynamics of different individuals' movements, and demonstrate that it facilitates coordination during interaction. We use our measure to confirm a key prediction of the theory of Similarity that coordination between two individuals performing a joint-action task is higher if their motions share similar Dynamic features. Furthermore, we use a virtual avatar driven by an interactive cognitive architecture based on feedback control theory to explore the effects of different kinematic features of the avatar motion on coordination with human players.
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Dynamic Similarity promotes interpersonal coordination in joint-action
Journal of the Royal Society Interface, 2016Co-Authors: Piotr Słowiński, Chao Zhai, Francesco Alderisio, Robin N. Salesse, Mathieu Gueugnon, Ludovic Marin, Benoît G. Bardy, Mario Di Bernardo, Krasimira Tsaneva-atanasovaAbstract:Human movement has been studied for decades and Dynamic laws of motion that are common to all humans have been derived. Yet, every individual moves differently from everyone else (faster/slower, harder/smoother etc). We propose here an index of such variability, namely an individual motor signature (IMS) able to capture the subtle differences in the way each of us moves. We show that the IMS of a person is time-invariant and that it significantly differs from those of other individuals. This allows us to quantify the Dynamic Similarity, a measure of rapport between Dynamics of different individuals' movements, and demonstrate that it facilitates coordination during interaction. We use our measure to confirm a key prediction of the theory of Similarity that coordination between two individuals performing a joint-action task is higher if their motions share similar Dynamic features. Furthermore, we use a virtual avatar driven by an interactive cognitive architecture based on feedback control theory to explore the effects of different kinematic features of the avatar motion on the coordination with human players.
Banda Ramadan - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Similarity aware inverted indexing for real time entity resolution
Knowledge Discovery and Data Mining, 2013Co-Authors: Banda Ramadan, Peter Christen, Huizhi Liang, Ross W Gayler, David HawkingAbstract:Entity resolution is the process of identifying groups of records in a single or multiple data sources that represent the same real-world entity. It is an important tool in data de-duplication, in linking records across databases, and in matching query records against a database of existing entities. Most existing entity resolution techniques complete the resolution process offline and on static databases. However, real-world databases are often Dynamic, and increasingly organizations need to resolve entities in real-time. Thus, there is a need for new techniques that facilitate working with Dynamic databases in real-time. In this paper, we propose a Dynamic Similarity-aware inverted indexing technique (DySimII) that meets these requirements. We also propose a frequency-filtered indexing technique where only the most frequent attribute values are indexed. We experimentally evaluate our techniques on a large real-world voter database. The results show that when the index size grows no appreciable increase is found in the average record insertion time (around 0.1 msec) and in the average query time (less than 0.1 sec). We also find that applying the frequency-filtered approach reduces the index size with only a slight drop in recall.
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PAKDD Workshops - Dynamic Similarity-Aware Inverted Indexing for Real-Time Entity Resolution
Lecture Notes in Computer Science, 2013Co-Authors: Banda Ramadan, Peter Christen, Huizhi Liang, Ross W Gayler, David HawkingAbstract:Entity resolution is the process of identifying groups of records in a single or multiple data sources that represent the same real-world entity. It is an important tool in data de-duplication, in linking records across databases, and in matching query records against a database of existing entities. Most existing entity resolution techniques complete the resolution process offline and on static databases. However, real-world databases are often Dynamic, and increasingly organizations need to resolve entities in real-time. Thus, there is a need for new techniques that facilitate working with Dynamic databases in real-time. In this paper, we propose a Dynamic Similarity-aware inverted indexing technique (DySimII) that meets these requirements. We also propose a frequency-filtered indexing technique where only the most frequent attribute values are indexed. We experimentally evaluate our techniques on a large real-world voter database. The results show that when the index size grows no appreciable increase is found in the average record insertion time (around 0.1 msec) and in the average query time (less than 0.1 sec). We also find that applying the frequency-filtered approach reduces the index size with only a slight drop in recall.
