Search results for "Partial least squares regression"
showing 10 items of 122 documents
Comparative Study of Several Machine Learning Algorithms for Classification of Unifloral Honeys
2021
Unifloral honeys are highly demanded by honey consumers, especially in Europe. To ensure that a honey belongs to a very appreciated botanical class, the classical methodology is palynological analysis to identify and count pollen grains. Highly trained personnel are needed to perform this task, which complicates the characterization of honey botanical origins. Organoleptic assessment of honey by expert personnel helps to confirm such classification. In this study, the ability of different machine learning (ML) algorithms to correctly classify seven types of Spanish honeys of single botanical origins (rosemary, citrus, lavender, sunflower, eucalyptus, heather and forest honeydew) was investi…
Detecting crop water status in mature olive orchards using vegetation spectral measurements.
2014
Full spectral measurements (350–2500 nm) at tree canopy and leaf levels and the corresponding leaf water potentials (LWP) were acquired in an olive grove of Sicily, at different hours of the day, during summer season 2011. The main objective of the work was to assess, on the basis of the experimental data-set, two different approaches to detect crop water status in terms of LWP. Specifically, using existing families of Vegetation Indices (VIs) and applying Partial Least Squares Regression (PLSR) were optimised and tested. The results indicated that a satisfactory estimation of LWP at tree canopy and leaf levels can be obtained using vegetation indices based on the near infrared–shortwave in…
Continuous 3-year outdoor operation of a flat-panel membrane photobioreactor to treat effluent from an anaerobic membrane bioreactor
2020
[EN] A membrane photobioreactor (MPBR) plant was operated continuously for 3 years to evaluate the separate effects of different factors, including: biomass and hydraulic retention times (BRT, HRT), light path (Lp), nitrification rate (NOxR), nutrient loading rates (NLR, PLR) and others. The overall effect of all these parameters which influence MPBR performance had not previously been assessed. The multivariate projection approach chosen for this study provided a good description of the collected data and facilitated their visualisation and interpretation. Forty variables used to control and assess MPBR performance were evaluated during three years of continuous outdoor operation by means …
Efeitos das práticas verdes na lealdade: proposta de um modelo para o segmento hoteleiro colombiano
2021
Resumen El propósito de este estudio fue analizar la incidencia de las prácticas verdes como impulsoras para generar confianza, satisfacción y lealtad en los huéspedes. Para ello, a partir de una muestra de 302 huéspedes de hoteles en Bogotá, Colombia, se estimó un modelo de ecuaciones estructurales a través de la regresión de mínimos cuadrados parciales. Los resultados obtenidos evidencian que las prácticas sostenibles contribuyen al aumento de la confianza y la satisfacción de los huéspedes, y que estas, a su vez, influyen positivamente en su lealtad hacia el hotel. Además, dichos resultados ponen de manifiesto que una comprensión más profunda del perfil de los turistas medioambientalment…
Fast and direct analysis of oxidation levels of oil-in-water emulsions using ATR-FTIR.
2019
International audience; Oxidation of omega-3 fatty acids is a major limitation on its enrichment in food and beverages. An efficient and simple method to monitor lipid oxidation in complex systems is essential to limit lipid oxidation during formulation and processing. Fish oil-in-water emulsions (20% v/v) were exposed to iron or free radical initiated oxidation. Conjugated dienes (CDs) were rapidly measured using a previously developed fat extraction method. Fourier transform infrared (FTIR) spectroscopy has been used to directly record chemical changes occurring during oxidation. Variations were noticed in different spectral regions despite the presence of broad water bands near 3400 and …
Consumer confidence: Causality links with subjective and objective information sources
2020
Abstract This study analyses the relationship of causality between consumer confidence and the economic information ecosystem from subjective (i.e., business sentiment) and objective sources (financial information from listed companies and the stock index). Our sample covers Spain from June 2011 to December 2018. Our results show that consumer confidence and economic information can exert a causality influence on each other. The results show Granger causality from IBEX35 and total assets in the financial sector and leverage of the companies in the energy sector to the consumer confidence index (CCI), in the first lag: from operating income in the telecommunications sector to the CCI in the …
Influence of Advertising on Brand Personality in The Airline Sector: The Case of Spain
2013
This article outlines the findings of a study employing a partial least squares (PLS) structural equation methodology to explore the relationship among advertising and brand personality (BP) dimension of a validated Aaker's model (1997) in the airline business. BP refers to the emotional side of brand image. It is created by all experiences of consumers with a brand. The model was validated using confirmatory factor analysis and the effect of advertising on BP has been tested using PLS. The findings suggest that advertising influences the formation of BP only in the sophistication dimension. These results invite managers in the airline companies sector to develop communication strategies to…
Preliminary results on direct quantitative determination of cocaine in impregnated materials by infrared spectroscopy
2018
Abstract Partial least squares models were built for the direct determination of cocaine in seized impregnated smuggled materials. Measurements are based on the attenuated total reflectance middle infrared spectra (ATR-MIR) and diffuse reflectance spectra in the near range (DR-NIR) obtained directly from the surface of the impregnated materials. The aforementioned procedures offer fast, cheap and environmentally friendly green alternatives to the reference method based on the extraction of the drug and its quantification by gas chromatography. Additionally it has been verified that results found are statistically comparable with those obtained by the reference method with root mean square e…
Variable selection for the determination of total polar materials in fried oils by near infrared spectroscopy
2018
Total polar materials (TPM) content is considered as the best indicator and the most common parameter to check the quality of deep-frying oils. The development of simpler and quicker analytical techniques than the available methods to monitor oil quality in restaurants and fried food outlets is an important topic related to the human health. This paper reports a comparison of the variable selection of near infrared (NIR) spectra by multiple linear regression (MLR-NIR) with partial least squares (PLS-NIR) models for the quantification of TPM in fried vegetable oils. The use of PLS-NIR offers an alternative in laboratory bench equipment for the determination of TPM in oils employed for fryin…
Comparison of near and mid infrared spectroscopy as green analytical tools for the determination of total polar materials in fried oils
2017
Abstract Total polar materials (TPM) are used as an indicator of the quality in the frying oil because of high values may be harmful for human health. Spanish legislation establishes the maximum level of total polar materials for frying fats and oils for human consumption around 25% (w/w). Official methods to monitor oil quality are time consuming and use a lot of chemicals; therefore it is necessary a simple and quick analytical technique to evaluate fried oils. Transmittance near-infrared (NIR) and attenuated total reflection mid-infrared (ATR-MIR) spectroscopy measurements, combined with partial least squares (PLS) regression, offer alternatives to determine TPM in fried oils with relati…