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investigación

Influence of multivariate modeling in the prediction of soil carbon by a portable infrared sensor

congresokorea Contribución Workshop Proceedings of the 13th International Conference on Intelligent Environments, Seoul, Korea, August 2017.

Abstract

The determination of carbon is one of the most important in soil analysis. However traditional techniques are costly and time consuming. In this manuscript we propose an alternative predictive approach based on portable mid-infrared spectroscopy data modeled by machine learning techniques. We evaluate the performance of different machine learning models and sample size to predict soil carbon in 457 Australian soils. The results show a good performance of the models. All models are validate by statistical tests. The best performing technique with a 99% of confidence level is the Gaussian Process providing a 98% of accuracy for the prediction of soil carbon. Moreover, this technique is the most robust for the different sample sizes tested. When compared with the commonly used Partial Least Squares Regression technique, the machine learning approaches provide more successful and balanced results.

Fuzzy clustering as rational partition method for QSAR

articuloQSARLas técnicas de Fuzzy Clustering podemos aplicarlas en diferentes campos. En este ejemplo tenemos una colaboración que busca mejorar los métodos QSAR, de técnicas computacionales relacionadas con el cálculo de propiedades fisicoquímicas moleculares.

Abstract

Various methods are used to make the partition of data sets for QSAR development and model validation. In this work we used a fuzzy minimals partitioning and we compare this methodology with another rational partition methods like k-means clustering (KMS) and Minimal Test Set Dissimilarity (MTSD). For the development of QSAR models Ordinary Least Squares (OLS) and Extreme Learning Machine (ELM) methods were used. The generated QSAR equations were validated by the coefficient of determination of the internal leave one out (LOO) cross validation method QLOO 2 and then the coefficient of the external test set Qext 2 was compared between partition methods. The results of this comparison showed that using fuzzy minimal for big and structurally diverse data sets gave an applicability domain similar to KMS and a better predictability models than both methods, KMS and MTSD.

Using SWAT and Fuzzy TOPSIS

paperWaterNos acaban de publicar un artículo: Using SWAT and Fuzzy TOPSIS to Assess the Impact of Climate Change in the Headwaters of the Segura River Basin (SE Spain).

Abstract

The Segura River Basin is one of the most water-stressed basins in Mediterranean Europe. If we add to the actual situation that most climate change projections forecast important decreases in water resource availability in the Mediterranean region, the situation will become totally unsustainable. This study assessed the impact of climate change in the headwaters of the Segura River Basin using the Soil and Water Assessment Tool (SWAT) with bias-corrected precipitation and temperature data from two Regional Climate Models (RCMs) for the medium term (2041–2070) and the long term (2071–2100) under two emission scenarios (RCP4.5 and RCP8.5). Bias correction was performed using the distribution mapping approach. The fuzzy TOPSIS technique was applied to rank a set of nine GCM–RCM combinations, choosing the climate models with a higher relative closeness. The study results show that the SWAT performed satisfactorily for both calibration (NSE = 0.80) and validation (NSE = 0.77) periods. Comparing the long-term and baseline (1971–2000) periods, precipitation showed a negative trend between 6% and 32%, whereas projected annual mean temperatures demonstrated an estimated increase of 1.5–3.3 °C. Water resources were estimated to experience a decrease of 2%–54%. These findings provide local water management authorities with very useful information in the face of climate change.

Mi contribución se centra en la aplicación de las técnicas de Fuzzy TOPSIS para la selección de los modelos del cambio de clima.

Parallel implementation of fuzzy minimals clustering algorithm

articuloESWA

Abstract

Clustering aims to classify different patterns into groups called clusters. Many algorithms for both hard and fuzzy clustering have been developed to deal with exploratory data analysis in many contexts such as image processing, pattern recognition, etc. However, we are witnessing the era of big data computing where computing resources are becoming the main bottleneck to deal with those large datasets. In this context, sequential algorithms need to be redesigned and even rethought to fully leverage the emergent massively parallel architectures. In this paper, we propose a parallel implementation of the fuzzy minimals clustering algorithm called Parallel Fuzzy Minimal (PFM). Our experimental results reveal linear speed-up of PFM when compared to the sequential counterpart version, keeping very good classification quality.

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