Enriching e-learning metadata through digital library usage analysis

Purpose: In this paper we propose an evaluation framework for analyzing learning objects usage, with the aim of extracting useful information for improving the quality of the metadata used to describe the learning objects, but also for personalization purposes, including user models and adaptive itineraries. Methodology: We present experimental results from the log usage analysis during one academic semester of two different subjects, 350 students. The experiment looks into raw server log data generated from the interactions of the students with the classroom learning objects, in order to find relevant information that can be used to improve the metadata used for describing both the learning objects and the learning process. Findings: Preliminary studies have been carried out in order to obtain an initial picture of the interactions between learners and the virtual campus, including both services and resources usage. These studies try to establish elationships between user profiles and their information and navigational behavior in the virtual campus, with the aim of promoting personalization and improving the understanding of what learning in virtual environments means. Research limitations: During the formal learning process, students use learning resources from the virtual classroom provided by the academic library, but they also search for information outside the virtual campus. Not all of these usage data are considered in the model we propose. Further research needs to be done in order to get a complete view of the information search behavior of students for improving the users’ profile and creating better personalized services. Practical implications: In this paper we suggest how a selection of fields used in the LOM standard could be used for enriching the description of learning objects, automatically in some cases, from the learning objects usage performed by an academic community. Originality: Ever since the beginnings of libraries, they have been a “quiet storage place”. With the development of digital libraries, they become a meeting place where explicit and implicit recommendations about information sources can be shared among users. Social and learning process interactions, therefore, can be considered another knowledge source

Cultius d'estiu de regadiu que ens poden ajudar a fer front a una menor disponibilitat d'aigua

La situació dels embassaments de Catalunya posa de manifest la fragilitat de l’abastament hídric pels diferents usos i, en especial, per l’aigua destinada a la producció d’aliments. La situació, a dia d’avui i segons les previsions disponibles, fan preveure que ens acostem a la sequera més rellevant dels darrers setanta anys.info:eu-repo/semantics/publishedVersio

Differential irrigation scheduling by an automated algorithm of water balance tuned by capacitance-type soil moisture sensors

Automated software tools are required to undertake the routine tasks and decision-making involved in scheduling irrigation. A key issue in this topic is how to integrate sensors in the scheduling approach. The objectives of this research were to test, in the context of drip-irrigated orchards: (a) the suitability of FAO’s water balance method, locally adjusted by sensors, as the basis for the scheduling algorithm, (b) the suitability of capacitance-type soil moisture sensors, and an approach for their automated interpretation, for providing feedback to the scheduling algorithm, and (c) the performance of these combined approaches in the autonomous scheduling of irrigation in an apple orchard with heterogeneous vigour. The trial consisted of applying for two years the proposed approaches using an experimental web application, IRRIX, which scheduled irrigation of two irrigation sectors, which differed in tree size. The automated system was compared with manual scheduling by a classical water balance and with the actual evapotranspiration determined by a weighing lysimeter located in the same orchard. Results show that the irrigation applied by the automated approach in the sector of larger trees agreed with the ET determined by the lysimeter and, overall, with the scheduling by an experienced irrigator using a classical water balance. Meanwhile, as a result of a different feedback from soil moisture sensors, the same system reduced irrigation in the sector of smaller trees by a similar amount to that expected from the differences between the two sectors in the fraction of photosynthetically active radiation. This study illustrates that the method of water balance complemented with capacitance-type soil moisture sensors provides a sound basis for automated irrigation scheduling in orchards.info:eu-repo/semantics/publishedVersio

Using Soil Moisture Sensors for Automated Irrigation Scheduling in a Plum Crop

The growing scarcity and competition for water resources requires the urgent implementation of measures to ensure their rational use. Farmers need affordable irrigation tools that allow them to take advantage of scientific know-how to improve water use efficiency in their common irrigation practices. The aim of this study is to test under field conditions, and adjust where required, an automated irrigation system that allows the establishment of regulated deficit irrigation (RDI) strategies in a stone fruit orchard. For this, an automated device with an algorithm which combines water-balance-based irrigation scheduling with a feedback adjustment mechanism using 15 capacitive sensors for continuous soil moisture measurement was used. The tests were carried out in 2016 and 2017 in Vegas Bajas del Guadiana (Extremadura, Spain) on an experimental plot of ‘Red Beaut’, an early-maturing Japanese plum cultivar. Three irrigation treatments were established: control, RDI and automatic. The control treatment was scheduled to cover crop water needs, a postharvest deficit irrigation (40% crop evapotranspiration (ETc)) strategy was applied in the RDI treatment, while the Automatic treatment simulated the RDI but without human intervention. After two years of testing, the automated system was able to “simulate” the irrigation scheduling programmed by a human expert without the need for human intervention.info:eu-repo/semantics/publishedVersio

Fins a quin punt les varietats de blat de moro de cicle més curt ens poden ajudar a fer front a una menor disponibilitat d'aigua?

info:eu-repo/semantics/publishedVersio

Assimilation of Sentinel-2 Biophysical Variables into a Digital Twin for the Automated Irrigation Scheduling of a Vineyard

Decision support systems (DSS) are needed to carry out precision irrigation. Key issues in this regard include how to deal with spatial variability and the adoption of deficit irrigation strategies at the field scale. A software application originally designed for water balance-based automated irrigation scheduling locally fine-tuned through the use of sensors has been further developed with the emerging paradigm of both digital twins and the Internet of Things (IoT). The aim of this research is to demonstrate the feasibility of automatically scheduling the irrigation of a commercial vineyard when adopting regulated deficit irrigation (RDI) strategies and assimilating in near real time the fraction of absorbed photosynthetically active radiation (fAPAR) obtained from Sentinel-2 imagery. In addition, simulations of crop evapotranspiration obtained by the digital twin were compared with remote sensing estimates using surface energy balance models and Copernicus-based inputs. Results showed that regression between instantaneous fAPAR and in situ measurements of the fraction of intercepted photosynthetically active radiation (fIPAR) had a coefficient of determination (R2) ranging from 0.61 to 0.91, and a root mean square deviation (RMSD) of 0.10. The conversion of fAPAR to a daily time step was dependent on row orientation. A site-specific automated irrigation scheduling was successfully adopted and an adaptive response allowed spontaneous adjustments in order to stress vines to a certain level at specific growing stages. Simulations of the soil water balance components performed well. The regression between digital twin simulations and remote sensing-estimated actual (two-source energy balance Priestley–Taylor modeling approach, TSEB-PTS2+S3) and potential (Penman–Monteith approach) evapotranspiration showed RMSD values of 0.98 mm/day and 1.14 mm/day, respectively.This research was funded by the projects IRRINTEGRAL (No. RTI2018-099949-R-C21) and DIGISPAC (No. TED2021-131237B-C21), both from the Ministry of Science, Innovation and Universities of the Spanish government.The authors would like to thank all the Efficient Use of Water in Agriculture program team at the IRTA for their technical support, as well as Family Torres winery. This study was undertaken as part of the Horizon 2020 Programme for Research and Innovation (H2020) of the European Commission, in the context of the Marie Sklodowska-Curie Research and Innovation Staff Exchange (RISE) action and ACCWA project: grant agreement No.: 823965.info:eu-repo/semantics/publishedVersio

Automatic Irrigation Scheduling on a Hedgerow Olive Orchard Using an Algorithm of Water Balance Readjusted with Soil Moisture Sensors

Recent technological advances have made possible automated irrigation scheduling using decision-support tools. These tools help farmers to make better decisions in the management of their irrigation system, thus increasing yields while preserving water resources. The aim of this study is to evaluate in a commercial plot an automated irrigation system combined with remote-sensing techniques and soil mapping that allows the establishment of regulated deficit irrigation (RDI) strategies. The study was carried out over 3 years (2015–2017) in a commercial hedgerow olive orchard of the variety ‘Arbequina’ located in Alvarado (Extremadura, Spain). An apparent electrical conductivity (ECa) map and a normalized difference vegetation index (NDVI) map were generated to characterize the spatial variability of the plot and classify the zones in homogeneous areas. Then, reference points were selected to monitor the different irrigation sectors. In 2015, the plot was irrigated according to the farmer’s technical criteria throughout the plot. In 2016 and 2017, two different areas of the plot were irrigated applying an RDI strategy, one under expert supervision and the other automatically. The results show that in a heterogeneous plot the use of new technologies can be useful to establish the ideal location for an automatic irrigation system. Furthermore, automatic irrigation scheduling made it possible to establish an RDI strategy recommended by an expert, resulting in the homogenization of production throughout the plot without the need for human intervention.info:eu-repo/semantics/publishedVersio

Analysis of the Variability in Soil Moisture Measurements by Capacitance Sensors in a Drip-Irrigated Orchard

Among the diverse techniques for monitoring soil moisture, capacitance-type soil moisture sensors are popular because of their low cost, low maintenance requirements, and acceptable performance. However, although in laboratory conditions the accuracy of these sensors is good, when installed in the field they tend to show large sensor-to-sensor differences, especially under drip irrigation. It makes difficult to decide in which positions the sensors are installed and the interpretation of the recorded data. The aim of this paper is to study the variability involved in the measurement of soil moisture by capacitance sensors in a drip-irrigated orchard and, using this information, find ways to optimize their usage to manage irrigation. For this purpose, the study examines the uncertainties in the measurement process plus the natural variability in the actual soil water dynamics. Measurements were collected by 57 sensors, located at 10 combinations of depth and position relative to the dripper. Our results showed large sensor-to-sensor differences, even when installed at equivalent depth and coordinates relative to the drippers. In contrast, differences among virtual sensors simulated using a HYDRUS-3D model at those soil locations were one order of magnitude smaller. Our results highlight, as a possible cause for the sensor-to-sensor differences in the measurements by capacitance sensors, the natural variability in size, shape, and centering of the wet area below the drippers, combined with the sharply defined variation in water content at the soil scale perceived by the sensors.info:eu-repo/semantics/publishedVersio

Fins a quin punt les varietats de blat de moro de cicle més curt ens poden ajudar a fer front a una menor disponibilitat d'aigua?

info:eu-repo/semantics/publishedVersio