Objective and subjective characterization of saxophone reeds

The subjective quality of single cane reeds used for saxophone or clarinet may be very different from a reed to another although reeds present the same shape and the same strength. In this work, we propose to compare three approaches for the characterization of reeds properties. The first approach consists in measuring the reed mechanical response ("in vitro" measurement) by means of a specific bench which gives equivalent dynamic parameters (mass, damping, stiffness) of the first vibration mode. The second approach deals with the measurement of playing parameters "in vivo", using specific sensors mounted on the instrument mouthpiece. These measurements provide specific parameters in playing condition, such as the threshold pressure or the spectral centroid of the sounds. Finally, subjective tests are performed with a musician in order to assess the reeds according to subjective criteria, characteristic of the perceived quality. Different reeds chosen for their subjective differences (rather difficult and dark, medium, rather easy and bright) are characterized by the three methods. First results show that correlations can be established between "in vivo" measurements and subjective assessments

Estimation of the survival probabilities by adjusting a Cox model to the tail

National audienceWithin the framework of a survival analysis model with censored life time data and an explanatory covariate, our goal is to predict the survival probability beyond the largest observed time. A Cox model with a constant underlying hazard function is proposed to adjust the tail of the life time distribution. Under some regularity conditions, we prove that the parameter estimators are convergent

Assessing the differences between numerical methods and real experiments for the evaluation of reach envelopes of the human body

The use of static human body dimensions to assess the human accessibility is an essential part of an ergonomic approach in user-centered design. Assessments of reach capability are commonly performed by exercising external anthropometry of human body parts, which may be found in anthropometric databases, to numerically define the reach area of an intended user population. The result is a reach envelope determined entirely by the segment lengths, without taking into account external variables, as the nature of the task or the physical capacities of the subject, which may influence the results. Considering the body as a simple assembly of static parts of different anthropometry is limiting. In this paper, the limit of validity of this approach is assessed by comparing the reach envelopes obtained by this method to those obtained with a simple two-dimensional experimental reaching task of a panel of subjects. Forty subjects experimentally evaluated the reach, first with the body constrained and second unconstrained. Results were recorded and compared with those obtained numerically with a model, based on their own anthropometric characteristics, previously measured. A statistical study of the results allowed the definition of the shape of a confidence bound containing the real reach envelope. The results indicated important differences between the experiment and the numerical evaluation of the reach envelope.Comment: Colloque National AIP-Prim\'eca, Mar 201

How should an electric vehicle sound? User and expert perception

International audienc

Study of the Non-negative Matrix Factorization behavior to estimate the urban traffic sound levels

ICSV'26 ; 26ème International Congress on Sound and Vibration , MONTREAL, CANADA, 11-/07/2019 - 17/07/2019The advent of low-cost acoustic sensor networks in cities raises new interesting approaches for improving the monitoring of the acoustic quality of cities. Many innovative approaches are developed to improve knowledge on sound environments: sound environment recognition, sound source detection, etc. In order to improve the road traffic noise mapping, the use of a specific version of the Non-negative Matrix Factorization (NMF), named thresholded initialized NMF, as a source separation method to estimate the sound level of road traffic from measurements, has proved to be a successful approach. This paper proposes to further detail the functioning of the thresholded initialized NMF on a corpus composed of urban sound scenes mixing traffic and specific interfering components with calibrated sound levels in order to better understand its behavior according to the different sources encountered. The study reveals the different performances of this approach depending on the noise levels of the interfering sources and their proximity to the urban traffic spectrum

Intervalles de confiance pour une proportion : lesquels doit-on enseigner ?

The most frequently taught confidence intervals for a proportion are the classical Wald (Ws) and the Clopper-Pearson (CP) ones because of the simplicity of their definition. However, their actual coverage probability of the parameter p is erratic, often quite far from the nominal probability which is aimed at. Other confidence intervals are clearly preferable to the former, but their expression is generally complex and they are difficult to interpret. But nevertheless, through a simple modification of the definition of the Ws and CP intervals, we obtain some confidence intervals with much better coverage probabilities. Namely, these confidence intervals are the Agresti-Coull and Mid-P intervals that we present here. We highly recommend them in a basic Statistics course.Comment: in French in Colloque Francophone International sur l'Enseignement de la Statistique -CFIES 2015, Jan 2015, Bordeaux, Franc

Comparative Analysis of Brass Wind Instruments With an Artificial Mouth: First Results

International audienceWe have developed in the past “artificial mouths” to study the behaviour of brass wind instruments (trumpet, trombone) in the playing situation, but without a musician. After using such devices to better understand the physical phenomena involved in brass instruments, we have built and used a new artificial mouth with the objective to test and set up instruments; the artificial mouth is considered here as a “test bench”. In this article, we describe the typical measurements that we have carried out on trumpets, in order to compare them (measurements of oscillation threshold, evolution of the playing frequency according to the dynamic level). As a first result, the artificial mouth allows one to show noticeable differences between instruments. We propose next some research paths which could be explored in order to better control the quality of instruments and, in the future, to introduce the use of an artificial mouth in the design process of brass instruments

PREFERENCE BASED SYSTEM: AN ASSISTANCE FOR CHOOSING A COMIC

International audienceThis paper presents a contribution to design an online preference based system. The objective of the system is to assist a customer in the products selection process. The product considered here to describe the application is the comic. Current e-commerce recommendation systems assist customers in this process. Nevertheless, quality of the recommendations produced remains a real challenge. There are products that are not recommended to customers though they would appreciate them and others recommended to them though they do not appreciate them. Quality and relevance of recommendations is addressed in this paper. The customer's choice is not only based on product characteristics but also on his/her perceptive expectations. Therefore, products recommendations are considered relevant since they meet customer's expectations and particularly perceptive ones. The suggested algorithm aims to recommend spontaneously comics to an active customer. It is mainly based on collaborative filtering and neighbourhood formation. Cluster of neighbours is formed. Neighbours share common perceptive preferences with the active customer. Favourite comics of the neighbours may interest the latter. Selection of the appropriate comics is based on the product characteristics expected by the active customer. The algorithm produces relevant comics which meet the active customer's expectations and particularly perceptive ones