A comparative Digital Soil Mapping (DSM) study using a non-supervised clustering analysis and an expert knowledge based model - A case study from Ahuachapán, El Salvador

DSM is the inference of spatial and temporal soil property variations using mathematical models based on quantitative relationships between environmental information and soil measurements. The quality of DSM information depends on the method and environmental covariates used for its estimations. We compared two DSM methods to predict soil properties such as Organic Matter “MO” (%), Sand (%), Clay (%), pH (H2O), Phosphorus (mg/kg), Effective Cationic Exchange Capacity “CICE” (cmol/L), Potassium (cmol/L) and Water Holding Capacity (mm/m) for the department of Ahuachapán in El Salvador to support the activities of the Agriculture Landscape Restoration Initiative (ALRI) in the countr

A comparative Digital Soil Mapping (DSM) study using a non-supervised clustering analysis and an expert knowledge based model - A case study from Ahuachapán, El Salvador

DSM is the inference of spatial and temporal soil property variations using mathematical models based on quantitative relationships between environmental information and soil measurements. The quality of DSM information depends on the method and environmental covariates used for its estimations. We compared two DSM methods to predict soil properties such as Organic Matter “MO” (%), Sand (%), Clay (%), pH (H2O), Phosphorus (mg/kg), Effective Cationic Exchange Capacity “CICE” (cmol/L), Potassium (cmol/L) and Water Holding Capacity (mm/m) for the department of Ahuachapán in El Salvador to support the activities of the Agriculture Landscape Restoration Initiative (ALRI) in the countr

Autotuning digital controller for current sensorless power factor corrector stage in continuous conduction mode

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. V. M. López, F. J. Azcondo, F. J. Díaz, and Á. de Castro, "Autotuning digital controller for current sensorless power factor corrector stage in continuous conduction mode", 2010 IEEE 12th Workshop on Control and Modeling for Power Electronics (COMPEL), Boulder (CO), 2010, pp. 1-8A circuit that compensates the volt-seconds error across the inductor in current sensorless digital control for continuous conduction mode power factor correction (PFC) stage is presented. Low cost ad-hoc sigma-delta analog to digital converters (ΣΔ ADCs) are used to sample the PFC input and output voltage. Instead of being measured, the input current is estimated in a digital circuit to be used in the current loop. A nonlinear carrier control is implemented in the digital controller in order to obtain the power factor correction. Drive signal delays cause differences between the digital current and the real current, producing that volt-seconds error. The control algorithm is compensated taking into account the delays. The influence of a wrong compensation is presented. Experimental results show power factor values and harmonic content within the IEC 61000-3-2 Class C standard in different operation conditions. Furthermore, the use of this PFC stage for electronic ballasts to compensate the effect of the utility voltage fluctuation in HID lamps is also verified taking advantage of the digital device capabilities.This work is sponsored by the Spanish Ministry of Education and Science through the project CICYT-TEC 2008-0175

High-resolution error compensation in continuous conduction mode power factor correction stage without current sensor

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. V. M. López-Martín, F. J. Azcondo, and Á. de Castro, "High-resolution error compensation in continuous conduction mode power factor correction stage without current sensor", in 2012 15th International Power Electronics and Motion Control Conference (EPE/PEMC), Novi Sad (Serbia), 2012.Continuous conduction mode power factor correction (PFC) without input current measurement is a step forward with respect to previously proposed PFC digital controllers. Inductance volt-second (vsL) measurement in each switching period enables the estimation of input current, but an accurate compensation of the small errors in the measured vsL is required. Otherwise, they are accumulated over a half-cycle line, leading to an appreciable current distortion. A vsL estimation is proposed, measuring the input (vin) and the the output voltage (vo). Discontinuous conduction mode (DCM) occurs near input line zero crossings, and is also detected by measuring MOSFET vds. This article analyzes the current estimation error caused by errors in the on-time estimation and voltage measurements, and proposes the minimization of vsL errors by cancelling the difference between estimated DCM (TDCMinereb) and real DCM (TDCMin) times with a signal (vdig), generated in the digital device. Therefore, the current estimation is calibrated using digital signals during the operation in DCM. Feedfoward coarse time error compensation is carried out with the measured delay of the drive signal, and then a fine compensation is achieved with a feedback loop that adjusts vdig. Experimental results are shown for a 1 kW boost PFC converter.This work was supported in part by the Spanish Ministry of Science TEC - FEDER 2011-2361

Current error compensation for current-sensorless power factor corrector stage in continuous conduction mode

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. V. M. Lopez-Martin, F. J. Azcondo, and A. de Castro, "Current error compensation for current-sensorless power factor corrector stage in continuous conduction mode", 2012 IEEE 13th Workshop on Control and Modeling for Power Electronics (COMPEL), Kyoto (Japan), 2012, pp. 1-8A universal digital PFC current-sensorless controller based on control of estimated current is presented. Parasitic elements cause a small difference between the measured input voltage and the voltage across the inductance in a boost converter, which must be taken into account to estimate the input current in a sensorless PFC digital controller. To compensate for the deviation caused by the parasitic elements, and so minimize the current estimation error, the article proposes a digital feedback control technique that cancels the time difference between DCM operation time of the real input current (TinDCM) and the estimated current (TrebDCM). Experimental results, obtained using a boost PFC converter under different conditions, are shown for verification purposes.This work was supported by the Spanish Ministry of Science TEC FEDER 2011-2361

Approximating Soil Organic Carbon Stock in the Eastern Plains of Colombia

In Colombia, the rise of agricultural and pastureland expansion continues to exert increasing pressure on the structure and ecological processes of savannahs in the Eastern Plains. However, the effect of land use change on soil properties is often unknown due to poor access to remote areas. Effective management and conservation of soils requires the development spatial approaches that measure and predict dynamic soil properties such as soil organic carbon (SOC). This study estimates the SOC stock in the Eastern Plains of Colombia, with validation and uncertainty analyses, using legacy data of 653 soil samples. A random forest model of nine environmental covariate layers was used to develop predictions of SOC content. Model validation was determined using the Taylor series method, and root-mean-squared error (RMSE) and mean error (ME) were calculated to assess model performance. We found that the model explained 50.28% of the variation within digital SOC content map. Raster layers of SOC content, bulk density, and coarse rock fragment within the Eastern Plains were used to calculate SOC stock within the region. With uncertainty, SOC stock in the topsoil of the Eastern Plains was 1.2 G t ha−1. We found that SOC content contributed nearly all the uncertainty in the SOC stock predictions, although better determinations of SOC stock can be obtained with the use of a more geomorphological diverse dataset. The digital soil maps developed in this study provide predictions of extant SOC content and stock in the topsoil of the Eastern Plains, important soil information that may provide insight into the development of research, regulatory, and legislative initiatives to conserve and manage this evolving ecosystem

Evaluación Hidrológica Superficial del Departamento de Ahuachapán, El Salvador: Iniciativa Raíces-Ahuachapán

Catholic Relief Services (CRS) está liderando la iniciativa “Raíces-Ahuachapán” (referida como Agricultural Landscape Restoration Initiative – ALRI en inglés), una iniciativa para promover agricultura restaurativa en paisajes críticos del departamento de Ahuachapán. Esta iniciativa está siendo financiada por la Fundación Howard G. Buffet y en estos momentos se encuentra en la fase 1/4 del plan estratégico propuesto hasta el 2030. CRS está implementando esta iniciativa en conjunto con tres instituciones del ámbito nacional (PRISMA, AZURE y CARITAS) y con el apoyo del Centro Internacional de Agricultura Tropical – CIAT, además de contar con el soporte de diferentes socios locales. La restauración de paisaje que se piensa realizar a través de esta iniciativa tiene como objetivo asistir a la recuperación de ecosistemas degradados, dañados o destruidos. Además, de implementar mejoras en tierras que han sido degradadas a una escala que permita la reconstrucción de la integridad ecológica y el mejoramiento de la vida de las personas. Dentro de los componentes de la iniciativa se quiere llevar a cabo la restauración de los servicios agroecosistémicos con un enfoque en la protección de los recursos hídricos en importantes áreas agrícolas. Basado en lo anterior, CIAT ha sido encargado de realizar una evaluación hidrológica del departamento de Ahuachapán que permita la identificación de áreas claves en la contribución de agua superficial tanto en época seca como de lluvia, a través de la combinación de herramientas de modelación hidrológica y sistemas de información geográfica (SIG)

Recomendaciones sobre escenarios de prácticas de manejo del uso de la tierra para mitigar la erosión/sedimentación e inundación en la subcuenca agua caliente

En el presente documento se resume el enfoque metodológico desarrollado e implementado por CIAT en el marco del proyecto Raíces-Ahuachapán, con el fin de proveer recomendaciones sobre escenarios de prácticas de manejo del uso de la tierra para mitigar la erosión/sedimentación y el riesgo de inundación en la subcuenca Agua Caliente

Trunk Control Measurement Scale (TCMS): Psychometric Properties of Cross-Cultural Adaptation and Validation of the Spanish Version

The aim of this study was to develop a Spanish Version of the Trunk Measurement Scale (TCMS-S) to analyze its validity and reliability and determine the Standard Error of Measurement (SEM) and Minimal Detectable Change (MDC) in children with Cerebral Palsy (CP). Participants were assessed twice 7–15 days apart with the TCMS-S and once with the Gross Motor Function Measurement-88 (GMFM-88), Pediatric Disability Inventory-Computer Adaptive Test (PEDI-CAT), Cerebral Palsy Quality of Life (CPQoL), and Gross Motor Classification System (GMFCS). Internal consistency was evaluated using Cronbach’s alpha, and the intraclass correlation (ICC) and kappa coefficients were used to investigate the agreement between the assessments. Finally, 96 participants with CP were included. The TCMS-S showed excellent internal consistency (Cronbach’s alpha = 0.95 [0.93 to 0.96]); was highly correlated with the GMFM-88 (rho = 0.816) and the “mobility” subscale of the PEDI-CAT (rho = 0.760); showed a moderate correlation with the “feeling about functioning” CPQoL subscale (rho = 0.576); and differentiated between the GMFCS levels. Excellent test–retest agreement was found for the total and subscale scores (ICC � 0.94 [0.89 to 0.97). For the total TCMS-S score, an SEM of 1.86 and an MDC of 5.15 were found. The TCMS-S is a valid and reliable tool for assessing trunk control in children with CP.Sección Deptal. de Radiología, Rehabilitación y Fisioterapia (Enfermería)Fac. de Enfermería, Fisioterapia y PodologíaTRUEUniversidad Europea de Madridpu