Articles by Sergio Camiz

In a recently published study, a textual dataset encoding a group of scenes depicted on Mesopotamian cylinder seals from the third millennium was submitted to Procrustes Analysis, considering Correspondence Analysis variations due to progressive reductions of the forms involved. The results seemed to indicate that a slight reduction in the number of forms used to describe the raw data would improve the Correspondence Analysis results. Indeed, the actual impact of each reduction on the outcome of the analyses could not be adequately identified if the forms were not considered as elements forming segments, i.e., sub-images of the scenes. In this paper, the results of the same methodology are presented, this time applied to repeated segments within the same dataset, i.e., sequences of textual forms that may describe sub-images of the described scenes. The comparison between the progressive reductions of repeated segments showed relevant differences between small (around 10% of the rarest segments) and large reductions. Indeed, the latter may undermine a consistent interpretation of the different finding sites, yet well represented keeping 90% of segments. Moreover, a reduction performed by hand and not on the frequency of occurrences provided better results.

The use of Textual Correspondence Analysis to investigate a corpus of iconographic compositions carved on Mesopotamian cylinder seals proved to be very useful to understand the peculiarities of the specimens from the points of view of geographic origin, typology and inner chronology. The presence of a relatively high number of rare forms in the data set – besides the hapax – led to think, however, that the extraction of the factors – so the outcomes of the analyses – could have been influenced heavily by them. For this reason, looking for an optimal composition and for the most effective encoding of the data set, a reduction of its rarest forms was performed to find the threshold which could allow to reconcile the need for keeping the useful encoded information with the best possible reduction of elements producing high inertia. Adopting the methodology known as Procrustes, the data table was thus progressively reduced, and each time investigated: the results so obtained were then used to reach a global assessment about how much each reduced data set could correspond to the optimized one.

The statistical technique known as Textual Correspondence Analysis has been used here to study the late third millennium Mesopotamian figurative languages which were used to produce the so-called presentation scenes in Ur III glyptic. For this investigation the authors prepared a data set that collected the codings of a corpus of Ur III presentation scenes known from cylinder seals or ancient seal impressions on administrative documents. In this paper we first offer a summary and the discussion of the aims, strategies and first results of this investigation, then the iconography of presentation scenes is interpreted through the classification of the scenes on the basis of the analysis of the forms and of their external features. The paper concludes with a general summing-up of the results and their meaning.

This work focuses on the images representing the myth of Ajax, son of Telamon, as represented in a corpus of finds from Greece and pre-Roman Italy. The iconography of the classical myth is studied together with other characters, such as kind of object, production, painting technique, place of finding, age. The age was fixed in intervals of 50 years, because of the wide chronological range and the uncertainty of the age of some finds. The data table crossing the finds with the characters was first submitted to Multiple Correspondence Analysis, where a strong relation was revealed. This suggested that an attempt should be made to estimate the age on the basis of the other characters. Qualitative Discriminant Analysis, applied to the objects with certain age, gave good classification functions that were used to estimate the age of the finds with uncertain age. In conclusion, the examination of the graphs shows how different meanings and functions of a Greek myth are illustrated throughout Classical Antiquity.

The problem of coding archaeological finds is discussed. The different items susceptible to coding are described according to the kind of information that must be collected. Some new coding techniques are described in particular: the landmarks technique, to be used for the shape analysis of corpora of finds all having a similar shape; the textual coding, useful for the study of images, once both the elements and attitudes and the sub-images composing the image are taken into account; a symbolic coding, to be used in the study of the syntactical structure of the images, describing the relations among items, regardless of the iconographical content. An overview of the exploratory analysis issues is given as conclusion.

In order to test the ability of textual coding to depict the features of structured images, a corpus of images of Near-Eastern seals of the late IVth millennium BC was studied through different exploratory analysis techniques. Two different coding systems were considered: the classical presence/absence coding of iconographical elements present in the images and a new textual coding, based on a formalised text describing the image. These were submitted to Multiple and Textual Correspondence Analyses. The textual analyses were performed according to two different coding systems, and several choices of the items involved. The results of the different analyses are discussed and compared here. In particular, textual analysis proved effective in substituting the classical coding in the description of the iconographic elements appearing in the images. In addition, it allowed us to broaden the investigation to include aspects of the images (occurrence of fixed sub-patterns and composition) which are beyond the capacities of classical coding. The ability of textual coding to select particular elements, and/or element sequences, to be taken into account in the analyses, was also considered an interesting feature for fine-tuning the analyses to the particular characters of specific corpora. Thus, the use of a formalised text as an intermediate between images and analysis tools proved to be a method worth using, in spite of the special care needed, and some still unsolved difficulties.

In order to analyse a corpus of 963 Near-Eastern Uruk/Jemdet Nasr period sealings, three levels of image structure were identified, as being a) the presence of iconographic elements, b) the presence of subpattern, i.e. small images contributing as a whole to the total image, and c) the general image pattern, considered only under the syntactical point of view. This paper is based on second level analyses, performed through textual exploratory analysis of a formalized text describing the sealings images. Two different textual correspondence analyses were performed: the first on textual forms and the second on repeated segments, i.e. repeated sequences of forms considered as a whole. In the paper, the quality of results is discussed, in particular comparing them to classical techniques based on manual coding and to a previous coding. In this case, a better distinction of different sealings groups resulted from forms analysis, whereas the one on repeated segments, although repeating the forms analysis general pattern, seems less satisfactory. Both results suggest to modify the automatic procedures used so far, in order to limit attention to presence/absence of forms on one side and to select manually the repeated segments actually corresponding to a subpattern, rather than considering all of them.