47 research outputs found
Book Reviews
Review of Prehistory, by Derek Roe; Aspects of Prehistory, by Grahame Clark; World Prehistory, by Grahame Clark; Introductory Readings in Archaeology, by Brian M. Fagan, ed.; The Origins of Civilization, by Carroll L. Riley; The Archaeology of Early Man, by J. M. Coles and E. S. Higgs; Shipwrecks and Archaeology, by Peter Throckmorton; A History of Dyed Textiles, by Stuart Robinson; Food in Antiquity, by Don and Patricia Brothwell; World Archaeology, Vol. 1, nos. 1, 2, 3, by Roy Hodson and Colin Platt, eds.; The Structure and Growth of Australia's Aboriginal Population, by F. Lancaster Jones; Attitudes and Social Conditions, by Ronald Taft, John L. M. Dawson, and Pamela Beasley; Aboriginal Settlements, by J. P. M. Long; The Destruction of Aboriginal Society, by C. D. Rowley; Aboriginal Advancement to Integration, by H. P. Schapper
Using chemical, microbial and fluorescence techniques to understand contaminant sources and pathways to wetlands in a conservation site
Sequências de culturas em sistema de semeadura direta: II - decomposição e liberação de nutrientes na entressafra
Data descriptor: a global multiproxy database for temperature reconstructions of the Common Era
Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The records are from trees, ice, sediment, corals, speleothems, documentary evidence, and other archives. They range in length from 50 to 2000 years, with a median of 547 years, while temporal resolution ranges from biweekly to centennial. Nearly half of the proxy time series are significantly correlated with HadCRUT4.2 surface temperature over the period 1850-2014. Global temperature composites show a remarkable degree of coherence between high-and low-resolution archives, with broadly similar patterns across archive types, terrestrial versus marine locations, and screening criteria. The database is suited to investigations of global and regional temperature variability over the Common Era, and is shared in the Linked Paleo Data (LiPD) format, including serializations in Matlab, R and Python. (TABLE) Since the pioneering work of D'Arrigo and Jacoby1-3, as well as Mann et al. 4,5, temperature reconstructions of the Common Era have become a key component of climate assessments6-9. Such reconstructions depend strongly on the composition of the underlying network of climate proxies10, and it is therefore critical for the climate community to have access to a community-vetted, quality-controlled database of temperature-sensitive records stored in a self-describing format. The Past Global Changes (PAGES) 2k consortium, a self-organized, international group of experts, recently assembled such a database, and used it to reconstruct surface temperature over continental-scale regions11 (hereafter, ` PAGES2k-2013'). This data descriptor presents version 2.0.0 of the PAGES2k proxy temperature database (Data Citation 1). It augments the PAGES2k-2013 collection of terrestrial records with marine records assembled by the Ocean2k working group at centennial12 and annual13 time scales. In addition to these previously published data compilations, this version includes substantially more records, extensive new metadata, and validation. Furthermore, the selection criteria for records included in this version are applied more uniformly and transparently across regions, resulting in a more cohesive data product. This data descriptor describes the contents of the database, the criteria for inclusion, and quantifies the relation of each record with instrumental temperature. In addition, the paleotemperature time series are summarized as composites to highlight the most salient decadal-to centennial-scale behaviour of the dataset and check mutual consistency between paleoclimate archives. We provide extensive Matlab code to probe the database-processing, filtering and aggregating it in various ways to investigate temperature variability over the Common Era. The unique approach to data stewardship and code-sharing employed here is designed to enable an unprecedented scale of investigation of the temperature history of the Common Era, by the scientific community and citizen-scientists alike
Finger vein verification system using repeated line tracking and dimensionality reduction using PCA algorithms with SURF matching
Human security becomes important in this spoofing attack world. The traditional ways that used to protect privacy such as Personal Identification Number (PIN) and smart card are getting replaced by the biometric methods due to its high risk for being forgotten and exposure. Examples of human bio-metrics are iris, face, voice and finger print. However, these biometric traits are not are not completely reliable and secure. Hence, finger vein has been studied. This paper will compare the performance of finger vein verification system with PCA and without PCA. There is no acquisition process in this paper as we used an open source finger-vein database called SDMULA-HMT. In preprocessing stage, finger image from database will undergo process such as Contrast-limited Adaptive Histogram Equalization (CLAHE) and noise filtering image for con-trast improvement. Then, the vein pattern was extracted using Repeated Line Tracking (RLT). The feature vector of the vein pattern was then dimensionality reduction by Principal Component Analysis (PCA). The Speeded-Up Robust Features (SURF) Algorithms is used to determine the interest points. Lastly, the Euclidean Distance (ED) between the points of these two feature vectors was figured out to estimate their similarity. The result shows that PCA can improve the accuracy of the verification system by reduce the data down into its basic component without much loss of the informatio
Palm vein recognition using scale invariant feature transform with RANSAC mismatching removal
Palm vein recognition has getting more attention and popular among all other biometrics methods. In order to apply this type of recognition system to society, obtain an accurate reading robustly and effectively become the most pop-ular research topic in this field. However, there are still an unsolved issues on accurate palm vein recognition although there are several research done. In this paper, impact of Random Sample Consensus (RANSAC) point mismatching re-moval and different wavelength spectrum to the recognition rate will be dis-cussed. CASIA Multi Spectral Palm Print Image database is used for this re-search. Scale Invariant Feature Transform (SIFT) and RANSAC mismatching removal will be adopted for vein extraction and point feature matching with Eu-clidean Distance. The results shows that SIFT algorithm with RANSAC mis-matching point removal achieved better recognition rate than without mismatch-ing point removal technique used. It can be proved that RANSAC mismatching point removal are able to remove outlier with preserving the correct point by im-proving the Equal Error Rate (EER) in recognition systems. In palm vein recog-nition system, higher wavelength spectrum of palm vein image will achieved higher verification rate. This can be shows that vein pattern are able and success-fully extract on the image with higher wavelength spectrum