Filtreler

2012 - 201912020 - 20221
Filtreleri Sıfırla

Ayarlar

Scopus Q: Q1 × Konu: Ensemble ×

Arama Sonuçları

Listeleniyor 1 - 2 / 2
  • Küçük Resim
    Yayın
    Eigenclassifiers for combining correlated classifiers
    (Elsevier Science Inc, 2012-03-15) Ulaş, Aydın; Yıldız, Olcay Taner; Alpaydın, Ahmet İbrahim Ethem
    In practice, classifiers in an ensemble are not independent. This paper is the continuation of our previous work on ensemble subset selection [A. Ulas, M. Semerci, O.T. Yildiz, E. Alpaydin, Incremental construction of classifier and discriminant ensembles, Information Sciences, 179 (9) (2009) 1298-1318] and has two parts: first, we investigate the effect of four factors on correlation: (i) algorithms used for training, (ii) hyperparameters of the algorithms, (iii) resampled training sets, (iv) input feature subsets. Simulations using 14 classifiers on 38 data sets indicate that hyperparameters and overlapping training sets have higher effect on positive correlation than features and algorithms. Second, we propose postprocessing before fusing using principal component analysis (PCA) to form uncorrelated eigenclassifiers from a set of correlated experts. Combining the information from all classifiers may be better than subset selection where some base classifiers are pruned before combination, because using all allows redundancy.
  • Küçük Resim
    Yayın
    The Worldwide C3S CORDEX Grand Ensemble A Major Contribution to Assess Regional Climate Change in the IPCC AR6 Atlas
    (American Meteorological Society, 2022-12) Diez-Sierra, Javier; Iturbide, Maialen; Gutierrez, Jose M.; Fernandez, Jesus; Milovac, Josipa; Cofino, Antonio S.; Cimadevilla, Ezequiel; Nikulin, Grigory; Levavasseur, Guillaume; Kjellstrom, Erik; Bulow, Katharina; Horanyi, Andras; Brookshaw, Anca; Garcia-Diez, Markel; Perez, Antonio; Bano-Medina, Jorge; Ahrens, Bodo; Alias, Antoinette; Ashfaq, Moetasim; Bukovsky, Melissa; Buonomo, Erasmo; Caluwaerts, Steven; Chou, Sin Chan; Christensen, Ole B.; Ciarlo, James M.; Coppola, Erika; Corre, Lola; Demory, Marie-Estelle; Djurdjevic, Vladimir; Evans, Jason P.; Fealy, Rowan; Feldmann, Hendrik; Jacob, Daniela; Jayanarayanan, Sanjay; Katzfey, Jack; Keuler, Klaus; Kittel, Christoph; Kurnaz, Mehmet Levent; Laprise, Rene; Lionello, Piero; McGinnis, Seth; Mercogliano, Paola; Nabat, Pierre; Öztürk, Tuğba; Panitz, Hans-Jurgen; Paquin, Dominique; Pieczka, Ildiko; Raffaele, Francesca; Remedio, Armelle Reca; Scinocca, John; Sevault, Florence; Somot, Samuel; Steger, Christian; Tangang, Fredolin; Teichmann, Claas; Termonia, Piet; Thatcher, Marcus; Torma, Csaba; van Meijgaard, Erik; Vautard, Robert; Warrach-Sagi, Kirsten; Winger, Katja; Zittis, George; Önol, Barış
    The collaboration between the Coordinated Regional Climate Downscaling Experiment (CORDEX) and the Earth System Grid Federation (ESGF) provides open access to an unprecedented ensemble of regional climate model (RCM) simulations, across the 14 CORDEX continental-scale domains, with global coverage. These simulations have been used as a new line of evidence to assess regional climate projections in the latest contribution of the Working Group I (WGI) to the IPCC Sixth Assessment Report (AR6), particularly in the regional chapters and the Atlas. Here, we present the work done in the framework of the Copernicus Climate Change Service (C3S) to assemble a consistent worldwide CORDEX grand ensemble, aligned with the deadlines and activities of IPCC AR6. This work addressed the uneven and heterogeneous availability of CORDEX ESGF data by supporting publication in CORDEX domains with few archived simulations and performing quality control. It also addressed the lack of comprehensive documentation by compiling information from all contributing regional models, allowing for an informed use of data. In addition to presenting the worldwide CORDEX dataset, we assess here its consistency for precipitation and temperature by comparing climate change signals in regions with overlapping CORDEX domains, obtaining overall coincident regional climate change signals. The C3S CORDEX dataset has been used for the assessment of regional climate change in the IPCC AR6 (and for the interactive Atlas) and is available through the Copernicus Climate Data Store (CDS).