4,241 research outputs found
Detecting and locating trending places using multimodal social network data
This paper presents a machine learning-based classifier for detecting points of interest through the combined use of images and text from social networks. This model exploits the transfer learning capabilities of the neural network architecture CLIP (Contrastive Language-Image Pre-Training) in multimodal environments using image and text. Different methodologies based on multimodal information are explored for the geolocation of the places detected. To this end, pre-trained neural network models are used for the classification of images and their associated texts. The result is a system that allows creating new synergies between images and texts in order to detect and geolocate trending places that has not been previously tagged by any other means, providing potentially relevant information for tasks such as cataloging specific types of places in a city for the tourism industry. The experiments carried out reveal that, in general, textual information is more accurate and relevant than visual cues in this multimodal setting.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research has been partially funded by project “Desarrollo de un ecosistema de datos abiertos para transformar el sector turístico” (GVA-COVID19/2021/103) funded by Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital de la Generalitat Valenciana, “A way of making Europe” European Regional Development Fund (ERDF) and MCIN/AEI/10.13039/501100011033 for supporting this work under the “CHAN-TWIN” project (grant TED2021-130890B-C21) and the HORIZON-MSCA-2021-SE-0 action number: 101086387, REMARKABLE, Rural Environmental Monitoring via ultra wide-ARea networKs And distriButed federated Learning. We also would like to thank Nvidia for their generous hardware donations that made these experiments possible
Exploiting the Relationship Between Visual and Textual Features in Social Networks for Image Classification with Zero-Shot Deep Learning
One of the main issues related to unsupervised machine learning is the cost of processing and extracting useful information from large datasets. In this work, we propose a classifier ensemble based on the transferable learning capabilities of the CLIP neural network architecture in multimodal environments (image and text) from social media. For this purpose, we used the InstaNY100K dataset and proposed a validation approach based on sampling techniques. Our experiments, based on image classification tasks according to the labels of the Places dataset, are performed by first considering only the visual part, and then adding the associated texts as support. The results obtained demonstrated that trained neural networks such as CLIP can be successfully applied to image classification with little fine-tuning, and considering the associated texts to the images can help to improve the accuracy depending on the goal. The results demonstrated what seems to be a promising research direction.This work was funded by the University of Alicante UAPOSTCOVID19-10 grant for “Collecting and publishing open data for the revival of the tourism sector post-COVID-19” project
Achieving Identity-based cryptography in a personal digital assistant
Continuous technological advances have allowed that mobile devices, such as Personal Digital Assistants (PDAs), can execute sophisticated applications that more often than not must be equipped with a layer of security that should include the confidentiality and the authentication services within its repertory. Nevertheless, when compared against front-end computing devices, most PDAs are still seen as constrained devices with limited processing and storage capabilities. In order to achieve Identity-Based Cryptography (IBC), which was an open problem proposed by Adi Shamir in 1984, Boneh and Franklin presented in Crypto 2001, a solution that uses bilinear pairings as its main building block. Since then, IBC has become an active area of investigation where many efficient IBC security protocols are proposed year after year. In this paper, we present a cryptographic application that allows the secure exchange of documents from a Personal Digital Assistant (PDA) that is wirelessly connected to other nodes. The architecture of our application is inspired by the traditional PGP (Pretty Good Privacy) email security protocol. Our application achieves identity-based authentication and confidentiality functionalities at the 80-bit security level through the usage of a cryptographic library that was coded in C++. Our library can perform basic primitives such as bilinear pairings defined over the binary field and the ternary field , as well as other required primitives known as map-to-point hash functions. We report the timings achieved by our application and we show that they compare well against other similar works published in the open literature
La cultura tributaria y su incidencia en la evasión tributaria en los comerciantes del mercado Chacra la Olla, Chimbote – 2020
El presente Informe de investigación denominado: La Cultura Tributaria y su
incidencia en la Evasión Tributaria en los comerciantes del Mercado Chacra la Olla,
Chimbote – 2020, tuvo como objetivo determinar la incidencia de la cultura tributaria
en la evasión tributaria de los socios del Mercado Chacra la Olla, Chimbote – 2020.
La metodología utilizada fue de enfoque cuantitativo, de tipo aplicada y de diseño
no experimental, transversal, descriptivo correlacional. La población estuvo
constituida por todos los socios del mercado Chacra la Olla y la muestra fue
calculada mediante una formula estadística que arrojó como resultado a 80
colaboradores del centro de abastos. Los instrumentos utilizados fueron el
cuestionario y la guía de análisis documental, estos instrumentos han sido
sometidos a expertos para su validez, la confiabilidad se ha realizado mediante la
prueba no paramétrica del Alpha de Cronbach. Los resultados obtenidos muestran
una correlación entre cultura tributaria y evasión tributaria de 0.767, lo que señala
una correlación positiva. Se concluyó que existe una relación elevada entre cultura
tributaria y evasión tributaria, ya que los socios al ser conscientes y tener una
educación tributaria les permite cumplir correctamente con sus obligaciones
tributarias y así minimizar la existencia de una evasión tributari
Observations on different post-fire bio-engineering interventions and vegetation response in a Pinus canariensis C. Sm. forest
On the Canary Islands, during the 2007 (30 July - 2 August) wildfire, about 18.000 hectares of forest were destroyed. After the event, to avoid erosion, a series of mixed check dams (wooden elements and stones with a core filled with forest residues) were built in the gullies created by the surface runoff. This first study aims to investigate the different responses of vegetation and its recovery after fire, with three different types of structures. We analyzed the performance and evolution of the mixed check dams nine years after their construction and the post-fire response of vegetation with the different types of bio-engineering techniques applied. The effects of the mixed check dams are expressed in terms of plant density, frequency, and cover both in absolute and in relative terms and the same effects were compared with those of the rocks, check dams, wattle fences, and structure in the surrounding areas. Our observations show that fire adaptation in the Canary Islands vegetation (pyrophyte plants), coupled with selected bio-engineering techniques, facilitated resprouting, seeds germination and a quick restoration of the forest ecosystem. The study confirms that simple, nature-based and low cost bio-engineering measures, which use local materials and are consistent with traditional building experiences effectively contribute to site restoration
Tomografía por emisión de positrones (PET) en oncología clínica no neurológica
Objetivos: Se recogen los resultados de una revisión de la literatura científica sobre la eficacia diagnóstica de
la PET en algunas condiciones oncológicas, exceptuando los tumores cerebrales. Se han analizado los parámetros
diagnósticos de sensibilidad (Se), especificidad (Sp) y exactitud diagnóstica, en comparación (cuando ha sido
posible) con otras tecnologías de imagen alternativas.Introducción, Objetivo y Ámbito del Informe, Métodos y resultados generales de la revisión sistemática de la evidencia científica, Resultados clínicos de la revisión sistemática de la evidencia científica, Resultados de la revisión no sistemática en otros cánceres, Discusión, Conclusiones. Anexo I: Cobertura en EE.UU. y Canadá, Anexo II: Fichas bibliográficas del estudio 1996, analizadas por la AETS. Referencias
Global Positioning System Analysis of Physical Demands in Elite Women’s Beach Handball Players in an Official Spanish Championship
This cross-sectional study aims to analyze the physical demands of elite beach handball players during an official competition. Nine elite female (mean age: 24.6 ± 4.0 years; body weight: 62.4 ± 4.6 kg; body height: 1.68 ± 0.059 m; training experience: 5 years; training: 6 h/week) beach handball players of the Spanish National Team were recruited for this study. A Global Positioning System was incorporated on each player’s back to analyze their movement patterns. Speed and distance were recorded at a sampling frequency of 15 Hz, whereas acceleration was recorded at 100 Hz by means of a built-in triaxial accelerometer. The main finding of the study is that 53% of the distance travelled is done at speeds between 1.5 and 5 km/h and 30% of the distance is between 9 and 13 km/h (83% of the total distance covered), which shows the intermittent efforts that beach handball involves at high intensity, as reflected in the analysis of the internal load with 62.82 ± 14.73% of the game time above 80% of the maximum heart rate. These data help to orientate training objectives to the physical demands required by the competition in order to optimize the players’ performance
Hydrometallurgical extraction of Li and Co from LiCoO2 particles–Experimental and Modeling
The use of lithium-ion batteries as energy storage in portable electronics and electric vehicles is increasing rapidly, which involves the consequent increase of battery waste. Hence, the development of reusing and recycling techniques is important to minimize the environmental impact of these residues and favor the circular economy goal. This paper presents experimental and modeling results for the hydrometallurgical treatment for recycling LiCoO2 cathodes from lithium-ion batteries. Previous experimental results for hydrometallurgical extraction showed that acidic leaching of LiCoO2 particles produced a non-stoichiometric extraction of lithium and cobalt. Furthermore, the maximum lithium extraction obtained experimentally seemed to be limited, reaching values of approximately 65–70%. In this paper, a physicochemical model is presented aiming to increase the understanding of the leaching process and the aforementioned limitations. The model describes the heterogeneous solid–liquid extraction mechanism and kinetics of LiCoO2 particles under a weakly reducing environment. The model presented here sets the basis for a more general theoretical framework that would describe the process under different acidic and reducing conditions. The model is validated with two sets of experiments at different conditions of acid concentration (0.1 and 2.5 M HCl) and solid to liquid ratio (5 and 50 g L−1). The COMSOL Multiphysics program was used to adjust the parameters in the kinetic model with the experimental results.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045. Paz-Garcia acknowledges financial support from the program “Proyectos I+D+i en el marco del Programa Operativo FEDER Andalucía 2014–2020”, No. UMA18-FEDERJA-279. Cerrillo-Gonzalez acknowledges the FPU grant obtained from the Spanish Ministry of Education. The University of Malaga is acknowledged for the financial support in the postdoctoral fellowship of Villen-Guzman
Leaching of LiCoO2 using H2O2 as reductant
The growing use of Lithium-Ion batteries (LIBs) in the field of electric vehicles and renewable energy storage entails the production of toxic and environmental hazardous wastes. Furthermore, some components in these batteries are classified as Critical Raw Material due to their supply risk and economic importance. Hence, the development of more efficient process to recycle LIBs is gaining importance for economic aspects and environmental protection.
In this work, the hydrometallurgical leaching process for the recovery of valuable metals from the cathode active materials of spent LIBs batteries was evaluated. Batch Experiments were carried out using LiCoO2 which is one of the most used cathodes in lithium-ion batteries. The selection of the extracting agent, its concentration, the reducing agent and the solid-liquid ratio are some of the parameters under study in this research.
Hydrochloric acid was used as the extracting agent and its concentration was modified from 0.1 M to 2.5 M while solid-liquid ratio (50 g/L), temperature (25 ºC) were fixed in all of them. The percentage of metal extracted was 31% of Co and 66% of Li for 0.1 M HCl solution. Extraction with 2.5M HCl solution was similar, 35% and 71% of Co and Li, respectively, but extracted in just 90 min, unlike the 72 h in the previous test. An experiment using H2O2 as a reducing agent was also performed, reaching a high percentage of metal extracted: 93% of Co and 100% of Li for a 0.6%vol of H2O2
Although tests have been carried out using LiCoO2, the technique can be applied to different kinds of cathode from spent batteries. The results suggested that the recovery of Co and Li is viable at optimized experimental conditions. The results indicated clearly that the dissolution of LiCoO2 particles is faster and more extensive when using more acidic extracting solution and stronger reducing agents, such as hydrogen peroxide.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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