Classifying organisms and artefacts by their outline shapes

We often wish to classify objects by their shapes. Indeed, the study of shapes is an important part of many scientific fields, such as evolutionary biology, structural biology, image processing and archaeology. However, mathematical shape spaces are rather complicated and nonlinear. The most widely used methods of shape analysis, geometric morphometrics, treat the shapes as sets of points. Diffeomorphic methods consider the underlying curve rather than points, but have rarely been applied to real-world problems. Using a machine classifier, we tested the ability of several of these methods to describe and classify the shapes of a variety of organic and man-made objects. We find that one method, based on square-root velocity functions (SRVFs), outperforms all others, including a standard geometric morphometric method (eigenshapes), and that it is also superior to human experts using shape alone. When the SRVF approach is constrained to take account of homologous landmarks it can accurately classify objects of very different shapes. The SRVF method identifies a shortest path between shapes, and we show that this can be used to estimate the shapes of intermediate steps in evolutionary series. Diffeomorphic shape analysis methods, we conclude, now provide practical and effective solutions to many shape description and classification problems in the natural and human sciences.</p

A Son of Nikon or Nikon Victorious: A New Inscription on a Fragment of a Pseudo Panathenaic Amphora

Recently, an inscribed fragment of a closed vase made of buff pinkish clay, covered with a red-orange wash, 11.8 cm wide and 8.4 cm high, and decorated with black, lustrous clay-paint surfaced briefly on the Swiss art market. It preserves a small section of the black tongue pattern on the shoulder and a wide black strip separating ornament and a panel with a straight glossy black line angled upwards; and the incomplete inscription TONIKONO[… . This paper endeavours to place the inscription and the name Nikon in a wider context and to examine the use of Pseudo-Panathenaic Amphorae

La Cerámica Ática y su Historiografía

History of Athenian figure-decorated pottery from the 6th to the 4th centuries BC, touching on technological aspects and iconography as well as on the find contexts of the vases. It also showcases current and past approaches to the study of Athenian pottery, making special emphasis on the figure of Sir John Beazley, the Oxford Professor who contributed to shape the discipline