M. Vives-Mestres, P. Daunis-i-Estadella, J. A. Martín-Fernández
Compositions are vectors of positive elements describing quantitatively the parts of some whole which carry exclusively relative information. Specific statistical methods based on the log-ratio approach are necessary because of its particular geometry. CUSUM Control Chart (CC) enables monitoring deviations from the process mean and have proven to be very effective in detecting small process shifts. The CUSUM CC can be used to detect changes in air pollution levels associated with the introduction of new traffic management schemes. We analyse the effect of the introduction of a new traffic management scheme in London using as indicator the hourly measurements of CO (mg/m3). The CUSUM is used to determine whether the new scheme has an effect on the CO. Assuming that CO concentration is a composition, we introduce the log-ratio methodology to produce the CUSUM CC. We compare our results with the classical approach and enhance the advantages and drawbacks of the proposed method.
Palabras clave: CUSUM, Control Chart, Composition, Log-ratio approach, Traffic Management
Programado
M08.2 Grupo de Análisis Multivariante y Clasificación IV
6 de septiembre de 2016 15:20
0.09 - Aula de proyectos 2
