Gaussian Process Modeling of In-Season Physiological Parameters of Spring Wheat Based on Airborne Imagery from Two Hyperspectral Cameras and Apparent Soil Electrical Conductivity

The remote sensing of the biophysical and biochemical parameters of crops facilitates the preparation of application maps for variable-rate nitrogen fertilization. According to comparative studies of machine learning algorithms, Gaussian process regression (GPR) can outperform more popular methods in the prediction of crop status from hyperspectral data. The present study evaluates GPR model accuracy in the context of spring wheat dry matter, nitrogen content, and nitrogen uptake estimation. Models with the squared exponential covariance function were trained on images from two hyperspectral cameras (a frenchFabry–Pérot interferometer camera and a push-broom scanner). The most accurate predictions were obtained for nitrogen uptake (R2=0.75–0.85, RPDP=2.0–2.6). Modifications of the basic workflow were then evaluated: the removal of soil pixels from the images prior to the training, data fusion with apparent soil electrical conductivity measurements, and replacing the Euclidean distance in the GPR covariance function with the spectral angle distance. Of these, the data fusion improved the performance while predicting nitrogen uptake and nitrogen content. The estimation accuracy of the latter parameter varied considerably across the two hyperspectral cameras. Satisfactory nitrogen content predictions (R2>0.8, RPDP>2.4) were obtained only in the data-fusion scenario, and only with a high spectral resolution push-broom device capable of capturing longer wavelengths, up to 1000 nm, while the full-frame camera spectral limit was 790 nm. The prediction performance and uncertainty metrics indicated the suitability of the models for precision agriculture applications. Moreover, the spatial patterns that emerged in the generated crop parameter maps accurately reflected the fertilization levels applied across the experimental area as well as the background variation of the abiotic growth conditions, further corroborating this conclusion.publishedVersio

An interlaboratory comparison of mid-infrared spectra acquisition: Instruments and procedures matter

Diffuse reflectance spectroscopy has been extensively employed to deliver timely and cost-effective predictions of a number of soil properties. However, although several soil spectral laboratories have been established worldwide, the distinct characteristics of instruments and operations still hamper further integration and interoperability across mid-infrared (MIR) soil spectral libraries. In this study, we conducted a large-scale ring trial experiment to understand the lab-to-lab variability of multiple MIR instruments. By developing a systematic evaluation of different mathematical treatments with modeling algorithms, including regular preprocessing and spectral standardization, we quantified and evaluated instruments' dissimilarity and how this impacts internal and shared model performance. We found that all instruments delivered good predictions when calibrated internally using the same instruments' characteristics and standard operating procedures by solely relying on regular spectral preprocessing that accounts for light scattering and multiplicative/additive effects, e.g., using standard normal variate (SNV). When performing model transfer from a large public library (the USDA NSSC-KSSL MIR library) to secondary instruments, good performance was also achieved by regular preprocessing (e.g., SNV) if both instruments shared the same manufacturer. However, significant differences between the KSSL MIR library and contrasting ring trial instruments responses were evident and confirmed by a semi-unsupervised spectral clustering. For heavily contrasting setups, spectral standardization was necessary before transferring prediction models. Non-linear model types like Cubist and memory-based learning delivered more precise estimates because they seemed to be less sensitive to spectral variations than global partial least square regression. In summary, the results from this study can assist new laboratories in building spectroscopy capacity utilizing existing MIR spectral libraries and support the recent global efforts to make soil spectroscopy universally accessible with centralized or shared operating procedures

Switch heating electrical equipment and external lighting at PKP Polish Railway Lines

W artykule omówiono urządzenia elektrycznego ogrzewania rozjazdów oraz oświetlenie zewnętrzne montowane na terenie PKP Polskie Linie Kolejowe S.A. Urządzenia elektrycznego ogrzewania rozjazdów zapewniają skuteczną ochronę rozjazdów w warunkach negatywnego oddziaływania warunków atmosferycznych. Ze względu na dużą energochłonność urządzeń elektrycznego ogrzewania rozjazdów omówiono sposoby zmniejszania zużycia energii elektrycznej. Oświetlenie głowic rozjazdowych ma na celu zwiększenie bezpieczeństwa prowadzenia ruchu pociągów. Dodatkowo w artykule wskazano możliwości efektywnego sterowania oświetleniem w wybranych rejonach stacji podczas zmniejszonego ruchu pociągów. Przedstawiono podstawowe wymagania dotyczące jakości energii elektrycznej zasilającej urządzenia na terenach kolejowych.The article discusses the devices for electric heating of turnouts and external lighting mounted on the premises of PKP Polish Railway Lines. Switchgear electrical switchgear devices provide effective protection of turnouts in conditions of adverse weather conditions. Due to the high consumption of switchgear heating devices, ways to reduce electricity consumption are discussed. Lighting of traveling heads is iontended to increase the safety of running trains. Additionally, the article indicates the possibilities of effective lighting control in selected areas of the station during reduced train traffic. Basic requirements for the quality of electricity supplying equipment on railway areas have been presented

Quality of electricity in power lines for receivers PKP Polish Railway Lines S.A.

Artykuł prezentuje definicje wynikające z aktualnych uwarunkowań prawnych i technicznych. Przedstawiono również problemy związane z jakością energii elektrycznej w podstacjach trakcyjnych w czasie pracy awaryjnej. Stan awaryjny powoduje nieregularności, które skutkują występowaniem zakłóceń wprowadzanych do sieci zasilającej i odbiorów zasilanych z podstacji trakcyjnych. Ponadto, przedstawiono wpływ występowania harmonicznych prądu na pracę wybranych odbiorów energii elektrycznej, jak również metody jego ograniczania. Wymieniono podstawowe wymagania co do jakości energii elektrycznej w PKP PLK S.A.The article presents definitions resulting from current legal and technical conditions. Problems related to the quality of electric power in traction substations during emergency operation are also presented. The emergency condition causes irregularities which result in disturbances being introduced into the supply network and loads supplied from traction substations. In addition, the influence of the occurrence of current harmonics on the operation of selected electricity reflections as well as the methods of its reduction are presented. The basic requirements regarding the quality of electricity in PKP Polish Railway Lines S.A. were mentioned

Urządzenia elektrycznego ogrzewania rozjazdów oraz oświetlenia zewnętrznego na terenie PKP Polskie Linie Kolejowe S.A.

W artykule omówiono urządzenia elektrycznego ogrzewania rozjazdów oraz oświetlenie zewnętrzne montowane na terenie PKP Polskie Linie Kolejowe S.A. Urządzenia elektrycznego ogrzewania rozjazdów zapewniają skuteczną ochronę rozjazdów w warunkach negatywnego oddziaływania warunków atmosferycznych. Ze względu na dużą energochłonność urządzeń elektrycznego ogrzewania rozjazdów omówiono sposoby zmniejszania zużycia energii elektrycznej. Oświetlenie głowic rozjazdowych ma na celu zwiększenie bezpieczeństwa prowadzenia ruchu pociągów. Dodatkowo w artykule wskazano możliwości efektywnego sterowania oświetleniem w wybranych rejonach stacji podczas zmniejszonego ruchu pociągów. Przedstawiono podstawowe wymagania dotyczące jakości energii elektrycznej zasilającej urządzenia na terenach kolejowych.The article discusses the devices for electric heating of turnouts and external lighting mounted on the premises of PKP Polish Railway Lines. Switchgear electrical switchgear devices provide effective protection of turnouts in conditions of adverse weather conditions. Due to the high consumption of switchgear heating devices, ways to reduce electricity consumption are discussed. Lighting of traveling heads is iontended to increase the safety of running trains. Additionally, the article indicates the possibilities of effective lighting control in selected areas of the station during reduced train traffic. Basic requirements for the quality of electricity supplying equipment on railway areas have been presented

Current harmonics in power lines and devices suppling railway consumers

W artykule przedstawiono funkcjonujące definicje, które wynikają z obowiązujących unormowań prawnych oraz technicznych. Przedstawiono również elementy układu prostowniczego podstacji, które podczas pracy awaryjnej powodują nieprawidłowości dotyczące występujących zaburzeń wprowadzanych do sieci zasilania oraz do odbiorców zasilanych z urządzeń podstacji trakcyjnej. Wymieniono poziomy napięcia zasilania w liniach zasilających podstacje trakcyjne. Wymieniono również niekorzystne oddziaływania harmonicznych na pracę wybranych odbiorników energii elektrycznej oraz sposoby ich zmniejszenia. Opisano wpływ harmonicznych na wybrane elementy takie jak: transformatory, kondensatory, generatory i silniki. Zostały również przedstawione podstawowe wymagania dotyczące jakości energii elektrycznej w urządzeniach PKP Polskie Linie Kolejowe S.A. oraz wymieniono typy podstawowych odbiorów kolejowych, które przede wszystkim służą do zapewnienia bezpiecznego prowadzenia ruchu pociągów.The article presents functioning definitions, which result from applicable legal and technical regulations. Also shown elements of the substation rectification circuit, which during emergency operation cause irregularities occurring disturbances introduced to the power grid and to recipients supplied from traction substation devices. Power supply voltage levels in power lines for traction substations are listed. Also the adverse effects of harmonics on the operation of selected electric energy receivers and the ways of their reduction have been mentioned. Describes the effect of harmonics on selected components such as transformers, capacitors, generators and motors. Basic requirements concerning the quality of electric energy in PKP Polish Railway Lines S.A. were also presented and the types of basic railway trains were exchanged, which are primarily used to ensure safe operation of trains

Calibration Spiking of MIR-DRIFTS Soil Spectra for Carbon Predictions Using PLSR Extensions and Log-Ratio Transformations

There is a need to minimize the usage of traditional laboratory reference methods in favor of spectroscopy for routine soil carbon monitoring, with potential cost savings existing especially for labile pools. Mid-infrared spectroscopy has been associated with accurate soil carbon predictions, but the method has not been researched extensively in connection to C lability. More studies are also needed on reducing the numbers of samples and on how to account for the compositional nature of C pools. This study compares performance of two classes of partial least squares regression models to predict soil carbon in a global (models trained to data from a spectral library), local (models trained to data from a target area), and calibration-spiking (spectral library augmented with target-area spectra) scheme. Topsoil samples were+ scanned with a Fourier-transform infrared spectrometer, total and hot-water extractable carbon determined, and isometric log-ratio coordinates derived from the latter measurements. The best RMSEP was estimated as 0.38 and 0.23 percentage points TC for the district and field scale, respectively—values sufficiently low to make only qualitative predictions according to the RPD and RPIQ criteria. Models estimating soil carbon lability performed unsatisfactorily, presumably due to low labile pool concentration. Traditional weighing of spiking samples by including multiple copies thereof in training data yielded better results than canonical partial least squares regression modeling with embedded weighing. Although local modeling was associated with the most accurate predictions, calibration spiking addressed better the trade-off between data acquisition costs and model quality. Calibration spiking with compositional data analysis is, therefore, recommended for routine monitoring

Computer simulations of deformations and tensions in the pipelines of hydraulic lifting systems

One of the methods of collecting polymetallic nodules from the sea floor is a hydraulic system using a single or double vertical pipeline. While mining, collecting pipelines suspended from a mining support vessel (MSV) move together. As a result of both the MSV’s motion with a suspended pipe system and water action (including deep-water currents) a vertical deflection and deformation occur along the pipeline. Simultaneously, stretching and bending tensions emerge along the pipeline. The article presents computer simulation results of vertical deflection and tensions within single and double vertical pipelines with fixed force from the ship’s movement (linear movement at constant speed) and regular force from the waves