Mostrar el registro sencillo del ítem

dc.contributor.authorArrechea Castillo, Darwin Alexis
dc.contributor.authorSolano Correa, Yady Tatiana
dc.contributor.authorMuñoz Ordóñez, Julián Fernando
dc.contributor.authorPencue Fierro, Edgar Leonairo
dc.contributor.authorFigueroa Casas, Apolinar
dc.date.accessioned2023-05-12T16:06:26Z
dc.date.available2023-05-12T16:06:26Z
dc.date.issued2023-05-11
dc.date.submitted2023-05-12
dc.identifier.citationArrechea-Castillo, D.A., Solano-Correa, Y.T., Muñoz-Ordóñez, J.F., Pencue-Fierro, E.L., Figueroa-Casas, A., 2023. Multiclass Land Use and Land Cover Classification of Andean Sub-Basins in Colombia with Sentinel-2 and Deep Learning. Remote Sensing 15, 2521. https://doi.org/10.3390/rs15102521spa
dc.identifier.urihttps://hdl.handle.net/20.500.12585/11850
dc.description.abstractLand Use and Land Cover (LULC) classification using remote sensing data is a challenging problem that has evolved with the update and launch of new satellites in orbit. As new satellites are launched with higher spatial and spectral resolution and shorter revisit times, LULC classification has evolved to take advantage of these improvements. However, these advancements also bring new challenges, such as the need for more sophisticated algorithms to process the increased volume and complexity of data. In recent years, deep learning techniques, such as convolutional neural networks (CNNs), have shown promising results in this area. Training deep learning models with complex architectures require cutting-edge hardware, which can be expensive and not accessible to everyone. In this study, a simple CNN based on the LeNet architecture is proposed to perform LULC classification over Sentinel-2 images. Simple CNNs such as LeNet require less computational resources compared to more-complex architectures. A total of 11 LULC classes were used for training and validating the model, which were then used for classifying the sub-basins. The analysis showed that the proposed CNN achieved an Overall Accuracy of 96.51% with a kappa coefficient of 0.962 in the validation data, outperforming traditional machine learning methods such as Random Forest, Support Vector Machine and Artificial Neural Networks, as well as state-of-the-art complex deep learning methods such as ResNet, DenseNet and EfficientNet. Moreover, despite being trained in over seven million images, it took five h to train, demonstrating that our simple CNN architecture is only effective but is also efficient.spa
dc.format.extent20 páginas
dc.format.mimetypeapplication/pdfspa
dc.language.isoengspa
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/*
dc.sourceMDPI Remote Sensing - Vol. 15 No. 10 (2023)spa
dc.titleMulticlass Land Use and Land Cover Classification of Andean Sub-Basins in Colombia with Sentinel-2 and Deep Learningspa
dcterms.bibliographicCitationOswald, S.M.; Hollosi, B.; Žuvela-Aloise, M.; See, L.; Guggenberger, S.; Hafner, W.; Prokop, G.; Storch, A.; Schieder, W. Using urban climate modelling and improved land use classifications to support climate change adaptation in urban environments: A case study for the city of Klagenfurt, Austria. Urban Clim. 2020, 31, 100582.spa
dcterms.bibliographicCitationBenhammou, Y.; Alcaraz-Segura, D.; Guirado, E.; Khaldi, R.; Achchab, B.; Herrera, F.; Tabik, S. Sentinel2GlobalLULC: A Sentinel-2 RGB image tile dataset for global land use/cover mapping with deep learning. Sci. Data 2022, 9, 20.spa
dcterms.bibliographicCitationYang, C.; Rottensteiner, F.; Heipke, C. Classification of land cover and land use based on convolutional neural networks. ISPRS Ann. Photogramm. Remote Sens. Spat. Inf. Sci. 2018, 4, 251–258.spa
dcterms.bibliographicCitationCarranza-García, M.; García-Gutiérrez, J.; Riquelme, J.C. A Framework for Evaluating Land Use and Land Cover Classification Using Convolutional Neural Networks. Remote Sens. 2019, 11, 274.spa
dcterms.bibliographicCitationChuvieco, E.; Li, J.; Yang, X. Advances in Earth Observation of Global Change, 1st ed.; Springer: Dordrecht, The Netherlands, 2010; ISBN 978-90-481-9084-3.spa
dcterms.bibliographicCitationSmyth, T.A.; Wilson, R.; Rooney, P.; Yates, K.L. Extent, accuracy and repeatability of bare sand and vegetation cover in dunes mapped from aerial imagery is highly variable. Aeolian Res. 2022, 56, 100799.spa
dcterms.bibliographicCitationLilay, M.Y.; Taye, G.D. Semantic segmentation model for land cover classification from satellite images in Gambella National Park, Ethiopia. SN Appl. Sci. 2023, 5, 15.spa
dcterms.bibliographicCitationYuh, Y.G.; Tracz, W.; Matthews, H.D.; Turner, S.E. Application of machine learning approaches for land cover monitoring in northern Cameroon. Ecol. Inform. 2023, 74, 101955.spa
dcterms.bibliographicCitationKeshtkar, H.; Voigt, W.; Alizadeh, E. Land-cover classification and analysis of change using machine-learning classifiers and multi-temporal remote sensing imagery. Arab. J. Geosci. 2017, 10, 154.spa
dcterms.bibliographicCitationPencue-Fierro, E.L.; Solano-Correa, Y.T.; Corrales-Munoz, J.C.; Figueroa-Casas, A. A Semi-Supervised Hybrid Approach for Multitemporal Multi-Region Multisensor Landsat Data Classification. IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens. 2016, 9, 5424–5435spa
dcterms.bibliographicCitationSwetanisha, S.; Panda, A.R.; Behera, D.K. Land use/land cover classification using machine learning models. Int. J. Electr. Comput. Eng. (IJECE) 2022, 12, 2040–2046.spa
dcterms.bibliographicCitationAlshari, E.A.; Abdulkareem, M.B.; Gawali, B.W. Classification of land use/land cover using artificial intelligence (ANN-RF). Front. Artif. Intell. 2023, 5, 964279spa
dcterms.bibliographicCitationPark, J.; Lee, Y.; Lee, J. Assessment of Machine Learning Algorithms for Land Cover Classification Using Remotely Sensed Data. Sens. Mater. 2021, 33, 3885.spa
dcterms.bibliographicCitationSaralioglu, E.; Vatandaslar, C. Land use/land cover classification with Landsat-8 and Landsat-9 satellite images: A comparative analysis between forest- and agriculture-dominated landscapes using different machine learning methods. Acta Geod. Geophys. 2022, 57, 695–716.spa
dcterms.bibliographicCitationRazafinimaro, A.; Hajalalaina, A.R.; Rakotonirainy, H.; Zafimarina, R. Land cover classification based optical satellite images using machine learning algorithms. Int. J. Adv. Intell. Inform. 2022, 8, 362–380spa
dcterms.bibliographicCitationPutri, K.A. Analysis of Land Cover Classification Results Using ANN, SVM, and RF Methods with R Programming Language (Case Research: Surabaya, Indonesia). IOP Conf. Ser. Earth Environ. Sci. 2023, 1127, 14spa
dcterms.bibliographicCitationKhosravi, I.; Jouybari-Moghaddam, Y. Hyperspectral Imbalanced Datasets Classification Using Filter-Based Forest Methods. IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens. 2019, 12, 4766–4772spa
dcterms.bibliographicCitationDhillon, A.; Verma, G.K. Convolutional neural network: A review of models, methodologies and applications to object detection. Prog. Artif. Intell. 2020, 9, 85–112.spa
dcterms.bibliographicCitationSánchez, A.-M.S.; González-Piqueras, J.; de la Ossa, L.; Calera, A. Convolutional Neural Networks for Agricultural Land Use Classification from Sentinel-2 Image Time Series. Remote Sens. 2022, 14, 5373spa
dcterms.bibliographicCitationKroupi, E.; Kesa, M.; Navarro-Sánchez, V.D.; Saeed, S.; Pelloquin, C.; Alhaddad, B.; Moreno, L.; Soria-Frisch, A.; Ruffini, G. Deep convolutional neural networks for land-cover classification with Sentinel-2 images. JARS 2019, 13, 024525spa
dcterms.bibliographicCitationCampos-Taberner, M.; García-Haro, F.; Martínez, B.; Gilabert, M. Deep learning para la clasificación de usos de suelo agrícola con Sentinel-2. Rev. Teledetec. 2020, 56, 35–48.spa
dcterms.bibliographicCitationZhang, W.; Tang, P.; Corpetti, T.; Zhao, L. WTS: A Weakly towards Strongly Supervised Learning Framework for Remote Sensing Land Cover Classification Using Segmentation Models. Remote Sens. 2021, 13, 394spa
dcterms.bibliographicCitationPedrayes, O.D.; Lema, D.G.; García, D.F.; Usamentiaga, R.; Alonso, Á. Evaluation of Semantic Segmentation Methods for Land Use with Spectral Imaging Using Sentinel-2 and PNOA Imagery. Remote Sens. 2021, 13, 2292.spa
dcterms.bibliographicCitationRuiz, O.D.M.; Idrobo, M.J.P.; Otero, S.J.D.; Figueroa, C.A. Effects of productive activities on the water quality for human consumption in an andean basin, a case study. Rev. Int. Contam. Ambient. 2017, 33, 361–375spa
dcterms.bibliographicCitationLopez, I.D.; Figueroa, A.; Corrales, J.C. Multi-Dimensional Data Preparation: A Process to Support Vulnerability Analysis and Climate Change Adaptation. IEEE Access 2020, 8, 87228–87242.spa
dcterms.bibliographicCitationPerdomo Chavarro, D. Determinación de la Variación de Microcontaminates (Agroquímicos) en la Subcuenca del Río Palacé Mediante un Modelo Matemático; Trabajo de grado-pregrado, Uniautónoma del Cauca, Facultad de Ciencias Ambientales y Desarrollo Sostenible, Programa de Ingeniería Ambiental y Sanitaria: Popayán, Colombia, 2021spa
dcterms.bibliographicCitationhantre Velasco, M. Análisis Comparativo de Cambios de Área en Coberturas en la Parte alta de la Subcuenca río Palacé, a Través de Imágenes Landsat Entre 1989 y 2016; Universidad de Manizales: Manizales, Colombia, 2017spa
dcterms.bibliographicCitationPhiri, D.; Simwanda, M.; Salekin, S.; Nyirenda, V.R.; Murayama, Y.; Ranagalage, M. Sentinel-2 Data for Land Cover/Use Mapping: A Review. Remote Sens. 2020, 12, 2291spa
dcterms.bibliographicCitationScepanovic, S.; Antropov, O.; Laurila, P.; Rauste, Y.; Ignatenko, V.; Praks, J. Wide-Area Land Cover Mapping with Sentinel-1 Imagery Using Deep Learning Semantic Segmentation Models. IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens. 2021, 14, 10357–10374spa
dcterms.bibliographicCitationEssien, P.; Figueiredo, C.A.O.B.; Takahashi, H.; Klutse, N.A.B.; Wrasse, C.M.; Afonso, J.M.D.S.; Quispe, D.P.; Lomotey, S.O.; Ayorinde, T.T.; Sobral, J.H.A.; et al. Intertropical Convergence Zone as the Possible Source Mechanism for Southward Propagating Medium-Scale Traveling Ionospheric Disturbances over South American Low-Latitude and Equatorial Region. Atmosphere 2022, 13, 15spa
dcterms.bibliographicCitationEuropean Space Agency (ESA) Copernicus Open Access Hub. Available online: https://scihub.copernicus.eu/dhus/#/home (accessed on 29 March 2023).spa
dcterms.bibliographicCitationLouis, J.; Pflug, B.; Main-Knorn, M.; Debaecker, V.; Mueller-Wilm, U.; Iannone, R.Q.; Giuseppe Cadau, E.; Boccia, V.; Gascon, F. Sentinel-2 Global Surface Reflectance Level-2a Product Generated with Sen2Cor. In Proceedings of the IGARSS 2019—2019 IEEE International Geoscience and Remote Sensing Symposium, Yokohama, Japan, 28 July–2 August 2019; pp. 8522–8525spa
dcterms.bibliographicCitationLouis, J.; Devignot, O.; Pessiot, L. Level-2A Algorithm Theoretical Basis Document; Remote Sensing Systems: Santa Rosa, CA, USA, 2021; p. 78spa
dcterms.bibliographicCitationAlaska Satellite Facility ASF Data Search. Available online: https://search.asf.alaska.edu/#/.html (accessed on 29 March 2023).spa
dcterms.bibliographicCitationYang, H.; Li, X.; Zhao, L.; Chen, S. An accurate and robust registration framework based on outlier removal and feature point adjustment for remote sensing images. Int. J. Remote Sens. 2021, 42, 8979–9002spa
dcterms.bibliographicCitationWang, Q.; Shi, W.; Li, Z.; Atkinson, P.M. Fusion of Sentinel-2 images. Remote Sens. Environ. 2016, 187, 241–252spa
dcterms.bibliographicCitationRen, H.; Feng, G. Are soil-adjusted vegetation indices better than soil-unadjusted vegetation indices for above-ground green biomass estimation in arid and semi-arid grasslands? Grass Forage Sci. 2014, 70, 611–619spa
dcterms.bibliographicCitationBaret, F.; Guyot, G. Potentials and limits of vegetation indices for LAI and APAR assessment. Remote Sens. Environ. 1991, 35, 161–173spa
dcterms.bibliographicCitationHuete, A.; Didan, K.; Miura, T.; Rodriguez, E.P.; Gao, X.; Ferreira, L.G. Overview of the radiometric and biophysical performance of the MODIS vegetation indices. Remote Sens. Environ. 2002, 83, 195–213spa
dcterms.bibliographicCitationHunt, E.R., Jr.; Daughtry, C.S.T.; Eitel, J.U.H.; Long, D.S. Remote Sensing Leaf Chlorophyll Content Using a Visible Band Index. Agron. J. 2011, 103, 1090–1099.spa
dcterms.bibliographicCitationNouaim, W.; Chakiri, S.; Rambourg, D.; Karaoui, I.; Ettaqy, A.; Chao, J.; Allouza, M.; Razoki, B.; Yazidi, M.; El Hmidi, F. Mapping the water erosion risk in the Lakhdar river basin (central High Atlas, Morocco). Geol. Ecol. Landscapes 2018, 3, 22–28.spa
dcterms.bibliographicCitationGao, B.-C. NDWI—A normalized difference water index for remote sensing of vegetation liquid water from space. Remote Sens. Environ. 1996, 58, 257–266.spa
dcterms.bibliographicCitationDogan, H.M. Applications of remote sensing and Geographic Information Systems to assess ferrous minerals and iron oxide of Tokat province in Turkey. Int. J. Remote Sens. 2008, 29, 221–233spa
dcterms.bibliographicCitationLiu, X.; Peng, Y.; Lu, Z.; Li, W.; Yu, J.; Ge, D.; Xiang, W. Feature-Fusion Segmentation Network for Landslide Detection Using High-Resolution Remote Sensing Images and Digital Elevation Model Data. IEEE Trans. Geosci. Remote Sens. 2023, 61, 4500314.spa
dcterms.bibliographicCitationKaufman, Y.J.; Tanre, D. Atmospherically resistant vegetation index (ARVI) for EOS-MODIS. IEEE Trans. Geosci. Remote Sens. 1992, 30, 261–270spa
dcterms.bibliographicCitationHancock, D.W.; Dougherty, C.T. Relationships between Blue- and Red-based Vegetation Indices and Leaf Area and Yield of Alfalfa. Crops Sci. 2007, 47, 2547–2556.spa
dcterms.bibliographicCitationGitelson, A.; Merzlyak, M.; Zur, Y.; Stark, R.; Gritz, U. Non-Destructive and Remote Sensing Techniques for Estimation of Vegetation Status; Papers in Natural Resources. In Proceedings of the Third European Conference on Precision Agriculture, Montpellier, France, 18–20 June 2001.spa
dcterms.bibliographicCitationTucker, C.; Elgin, J.; McMurtrey, J.; Fan, C. Monitoring corn and soybean crop development with hand-held radiometer spectral data. Remote Sens. Environ. 1979, 8, 237–248spa
dcterms.bibliographicCitationGobron, N.; Pinty, B.; Verstraete, M.M.; Widlowski, J.-L. Advanced vegetation indices optimized for up-coming sensors: Design, performance, and applications. IEEE Trans. Geosci. Remote Sens. 2000, 38, 2489–2505.spa
dcterms.bibliographicCitationCrippen, R. Calculating the vegetation index faster. Remote Sens. Environ. 1990, 34, 71–73spa
dcterms.bibliographicCitationCarlson, T.N.; Ripley, D.A. On the relation between NDVI, fractional vegetation cover, and leaf area index. Remote Sens. Environ. 1997, 62, 241–252.spa
dcterms.bibliographicCitationCarter, G.A. Ratios of leaf reflectances in narrow wavebands as indicators of plant stress. Int. J. Remote Sens. 1994, 15, 697–703spa
dcterms.bibliographicCitationHuete, A.R. A soil-adjusted vegetation index (SAVI). Remote Sens. Environ. 1988, 25, 295–309.spa
dcterms.bibliographicCitationYan, C.; Fan, X.; Fan, J.; Yu, L.; Wang, N.; Chen, L.; Li, X. HyFormer: Hybrid Transformer and CNN for Pixel-Level Multispectral Image Land Cover Classification. Int. J. Environ. Res. Public Health 2023, 20, 3059spa
dcterms.bibliographicCitationLecun, Y.; Bottou, L.; Bengio, Y.; Haffner, P. Gradient-based learning applied to document recognition. Proc. IEEE 1998, 86, 2278–2324spa
dcterms.bibliographicCitationMuckley, L.; Garforth, J. Multi-Input ConvLSTM for Flood Extent Prediction. In Proceedings of the Pattern Recognition. ICPR International Workshops and Challenges; Del Bimbo, A., Cucchiara, R., Sclaroff, S., Farinella, G.M., Mei, T., Bertini, M., Escalante, H.J., Vezzani, R., Eds.; Springer International Publishing: Cham, Switzerland, 2021; pp. 75–85spa
dcterms.bibliographicCitationThangadeepiga, E.; Alagu Raja, R.A. Remote Sensing-Based Crop Identification Using Deep Learning. In Intelligent Data Engineering and Analytics; Satapathy, S.C., Zhang, Y.-D., Bhateja, V., Majhi, R., Eds.; Springer: Singapore, 2021; pp. 109–122.spa
dcterms.bibliographicCitationThe Sequential Model|TensorFlow Core. Available online: https://www.tensorflow.org/guide/keras/sequential_model (accessed on 15 March 2023).spa
dcterms.bibliographicCitationLenail, A. NN-SVG: Publication-Ready Neural Network Architecture Schematics. J. Open Source Softw. 2019, 4, 747spa
dcterms.bibliographicCitationAlrasheedi, F.; Zhong, X.; Huang, P.-C. Padding Module: Learning the Padding in Deep Neural Networks. IEEE Access 2023, 11, 7348–7357.spa
dcterms.bibliographicCitationMuñoz-Ordóñez, J.; Cobos, C.; Mendoza, M.; Herrera-Viedma, E.; Herrera, F.; Tabik, S. Framework for the Training of Deep Neural Networks in TensorFlow Using Metaheuristics. In Intelligent Data Engineering and Automated Learning—IDEAL 2018; Yin, H., Camacho, D., Novais, P., Tallón-Ballesteros, A.J., Eds.; Springer International Publishing: Cham, Switzerland, 2018; pp. 801–811.spa
dcterms.bibliographicCitationZanaga, D.; Van De Kerchove, R.; Daems, D.; De Keersmaecker, W.; Brockmann, C.; Kirches, G.; Wevers, J.; Cartus, O.; Santoro, M.; Fritz, S.; et al. ESA WorldCover 10 m 2021 V200; European Space Agency: Paris, France, 2022spa
dcterms.bibliographicCitationRonneberger, O.; Fischer, P.; Brox, T. U-Net: Convolutional Networks for Biomedical Image Segmentation. In Medical Image Computing and Computer-Assisted Intervention—MICCAI 2015; Navab, N., Hornegger, J., Wells, W.M., Frangi, A.F., Eds.; Springer International Publishing: Cham, Switzerland, 2015; pp. 234–241spa
dcterms.bibliographicCitationChen, L.-C.; Papandreou, G.; Kokkinos, I.; Murphy, K.; Yuille, A.L. DeepLab: Semantic Image Segmentation with Deep Convolutional Nets, Atrous Convolution, and Fully Connected CRFs. IEEE Trans. Pattern Anal. Mach. Intell. 2018, 40, 834–848.spa
dcterms.bibliographicCitationKrizhevsky, A.; Sutskever, I.; Hinton, G.E. Imagenet classification with deep convolutional neural networks. Commun. ACM 2017, 60, 84–90spa
dcterms.bibliographicCitationZeiler, M.D.; Fergus, R. Visualizing and Understanding Convolutional Networks. In Computer Vision—ECCV 2014; Fleet, D., Pajdla, T., Schiele, B., Tuytelaars, T., Eds.; Springer International Publishing: Cham, Switzerland, 2014; pp. 818–833spa
dcterms.bibliographicCitationSzegedy, C.; Liu, W.; Jia, Y.; Sermanet, P.; Reed, S.; Anguelov, D.; Erhan, D.; Vanhoucke, V.; Rabinovich, A. Going Deeper with Convolutions. In Proceedings of the 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Boston, MA, USA, 7–12 June 2015; pp. 1–9.spa
dcterms.bibliographicCitationSimonyan, K.; Zisserman, A. Very Deep Convolutional Networks for Large-Scale Image Recognition. arXiv 2015, arXiv:1409.1556spa
dcterms.bibliographicCitationHe, K.; Zhang, X.; Ren, S.; Sun, J. Deep Residual Learning for Image Recognition. In Proceedings of the 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Las Vegas, NV, USA, 27–30 June 2016; pp. 770–778spa
dcterms.bibliographicCitationHuang, G.; Liu, Z.; Van Der Maaten, L.; Weinberger, K.Q. Densely Connected Convolutional Networks. In Proceedings of the 2017 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Honolulu, HI, USA, 21–26 July 2017; pp. 2261–2269spa
dcterms.bibliographicCitationTan, M.; Le, Q.V. EfficientNet: Rethinking Model Scaling for Convolutional Neural Networks. In Proceedings of the International Conference on Machine Learning 2019, Long Beach, CA, USA, 9–15 June 2019; pp. 10691–10700.spa
datacite.rightshttp://purl.org/coar/access_right/c_abf2spa
oaire.versionhttp://purl.org/coar/version/c_970fb48d4fbd8a85spa
dc.type.driverinfo:eu-repo/semantics/articlespa
dc.type.hasversioninfo:eu-repo/semantics/publishedVersionspa
dc.identifier.doi10.3390/rs15102521
dc.subject.keywordsLand Cover Classificationspa
dc.subject.keywordsLand Use Classificationspa
dc.subject.keywordsDeep Learningspa
dc.subject.keywordsConvolutional Neural Networkspa
dc.subject.keywordsRemote Sensingspa
dc.subject.keywordsSentinel-2spa
dc.rights.accessrightsinfo:eu-repo/semantics/openAccessspa
dc.rights.ccAttribution-NonCommercial-NoDerivatives 4.0 Internacional*
dc.identifier.instnameUniversidad Tecnológica de Bolívarspa
dc.identifier.reponameRepositorio Universidad Tecnológica de Bolívarspa
dc.publisher.placeCartagena de Indiasspa
dc.subject.armarcLEMB
dc.type.spahttp://purl.org/coar/resource_type/c_6501spa
dc.audiencePúblico generalspa
dc.publisher.sedeCampus Tecnológicospa
oaire.resourcetypehttp://purl.org/coar/resource_type/c_2df8fbb1spa


Ficheros en el ítem

Thumbnail
Thumbnail

Este ítem aparece en la(s) siguiente(s) colección(ones)

Mostrar el registro sencillo del ítem

http://creativecommons.org/licenses/by-nc-nd/4.0/
http://creativecommons.org/licenses/by-nc-nd/4.0/

Universidad Tecnológica de Bolívar - 2017 Institución de Educación Superior sujeta a inspección y vigilancia por el Ministerio de Educación Nacional. Resolución No 961 del 26 de octubre de 1970 a través de la cual la Gobernación de Bolívar otorga la Personería Jurídica a la Universidad Tecnológica de Bolívar.