ABSTRACT
Near-infrared spectroscopy ( NIR ) is widely used in the area of food quantitative and qualitative analysis.Variable selection technique is a critical step of the spectrum modeling with the development of chemometrics.In this study, a novel variable selection strategy, automatic weighting variable combination population analysis (AWVCPA), was proposed.Firstly, binary matrix sampling (BMS) strategy that gives each variable the same chance to be selected and generates different variable combinations, was used to produce a population of subsets to construct a population of sub-models.Then, the variable frequency ( Fre) and partial least squares regression ( Reg) , which were two kinds of information vector ( IVs) were weighted to obtain the value of the contribution of each spectral variables, the influence of two IVs of Rre and Reg was considered to each spectral variable.Finally, it used the exponentially decreasing function ( EDF) to remove the low contribution wavelengths so as to select the characteristic variable.In the case of near infrared spectrum of beer and corn, the prediction model based on partial least squares ( PLS ) was established.Compared with other variable selection methods, the research showed that AWVCPA was the best variable selection strategy in the same situation.It had 72.7% improvement compared AWVCPA-PLS with PLS and the predicted root mean square error (RMSEP) decreased from 0.5348 to 0.1457 on beer dataset.It had 64.7% improvement compared AWVCPA-PLS with PLS and the RMSEP decreased from 0.0702 to 0.0248 on corn dataset.
ABSTRACT
Objective To explore the characteristics of emotion recognition in children aged 7-14 years. Methods Nine hundred and sixty-one students aged 7-14 years were enrolled to rate the emotion dimensions of valence, arousal and dominance with the scale of Native Chinese Affective Picture System for Children. The relationship among scores of each emotion dimension was analysed, and the differences in age and gender of each emotion dimension were determined. Results For positive pictures (score of valence >6), the score of valence was positively related to that of arousal and dominate (r=0.56, r=0.40, P<0.01). For neutral pictures (score of valence 4-6), the score of valence was negatively related to that of arousal (r=-0.70, P<0.01) and positively related to that of dominance (r=0.69, P<0.01). For negative pictures (score of valence<4), the score of arousal was negatively related to that of dominance (r=-0.95, P<0.01). There were significant differences in scores of emotion dimensions between genders (P<0.05). There were significant differences in scores of arousal and dominance among children with different ages (P<0.01). Age was weakly negatively related to score of arousal (r=-0.18, P<0.01), and was weakly positively related to that of dominance (r=0.10, P<0.01). Conclusion There are significant differences in age and gender for emotion recognition in children, and the ratings are various among pictures with different characteristics, which needs to be considered in further researches.