A REVIEW OF SUPERVISED AND UNSUPERVISED PATTERN RECOGNITION IN ARCHAEOMETRY*

Principal component, cluster and discriminant analysis are multivariate statistical methods that are widely used in archaeometry. They are examples of what are known in some literatures as unsupervised and supervised learning methods. Over the past 20 years or so, a wide variety of other learning methods have been developed that take advantage of modern computing power and, in some cases, have been designed to handle data sets more complex than those often used in archaeometric data analysis. To date, these methods have had little impact on archaeometry. This paper reviews, in a largely non‐technical manner, the ideas behind these newer methods; illustrates their use on a variety of data sets; and attempts to assess their potential for future archaeometric use.     

ON STATISTICAL APPROACHES TO THE STUDY OF CERAMIC ARTEFACTS USING GEOCHEMICAL AND PETROGRAPHIC DATA*

The scientific analysis of ceramics often has the aim of identifying groups of similar artefacts. Much published work focuses on analysis of data derived from geochemical or mineralogical techniques. The former is more likely to be subjected to quantitative statistical analysis. This paper examines some approaches to the statistical analysis of data arising from both kinds of techniques, including ‘mixed‐mode’ methods where both types of data are incorporated into analysis. The approaches are illustrated using data derived from 88 Late Bronze Age transport jars from Kommos, Crete. Results suggest that the mixed‐mode approach can provide additional insight into the data.     

A Methodological Approach Towards Conservation

Abstract

Since conservation became a recognized discipline, professionals involved in conservation projects have tried to find the best criteria for their interventions. Often these criteria remain quite vague, based on the idea that every historic building has its own special conditions, which make its problems different from other buildings. This conviction, which is appropriate at one level, has serious consequences due to the lack of a consistent methodology. More than a lack of criteria, we might talk about a lack of 'habit' in identifying values in the Mediterranean region: the concept of values is much more widespread in Anglo-Saxon countries.

If we take a look at the history of conservation, there are a number of cases which are often used as models: for example, the Colosseum or the Arch of Titus in Rome, both interventions which are greatly admired and included in many conservation manuals. More recently there are projects which are widely accepted by the heritage conservation community as well: the paper explores the Palace of the Partal (Granada), the Villa Romana del Casale (Piazza Armerina), the theatre at Orange, and the Insula Orientalis I in Herculaneum. In this article, I suggest that there are constant elements within these conservation projects, reflecting typological, structural, constructional, functional, aesthetic, formal, historical, and symbolic values. These features represent a way of planning a conservation project and a critical methodology to judge the outcomes of the project in an objective manner. The methodology is qualitative rather than quantitative. All historic buildings have a set of values developed from their origins and throughout their history. These values can be analysed to extract the most important elements to be preserved. Analysing the values of our built heritage will allow us to create better decision-making processes.     

STATISTICAL ASPECTS OF POTTERY QUANTIFICATION FOR THE DATING OF SOME ARCHAEOLOGICAL CONTEXTS*

This paper describes some statistical analyses of a particular archaeological material (pottery) originating at some sites in the city of Tours. An important part of the archaeological study of pottery is the comparison of ceramic assemblages to establish the absolute dates of contexts. In this paper, a statistical model is built to assess this comparison. The statistical procedure uses classical tools (correspondence analysis, linear regression and resampling methods) in an iterative scheme. Archaeologists may find in the paper a useful set of known statistical methods, while statisticians can learn a method of ‘arranging’ well‐known techniques. No method is new, but their combination is characteristic of this application.     

An Empirical Comparison of Edge Effect Correction Methods Applied to K‐function Analysis

This paper explores various edge correction methods for K‐function analysis via Monte Carlo simulation. The correction methods discussed here are Ripley's circumference correction, a toroidal correction, and a guard area correction. First, simulation envelopes for a random point pattern are constructed for each edge correction method. Then statistical powers of these envelopes are analyzed in terms of the probability of detecting clustering and regularity in simulated clustering/regularity patterns. In addition to the K‐function, K(h), determined for individual distances, h, an overall statistic k is also examined. A major finding of this paper is that the K‐function method adjusted by either the Ripley or toroidal edge correction method is more powerful than what is not adjusted or adjusted by the guard area method. Another is that the overall statistic k outperforms the individual K(h) across almost the entire range of potential distances h.     

Access relative to need for community conservation funding in Australia

ABSTRACT

In a climate of scarce resources for heritage preservation, there is a need to develop principles and methodology for assessing and responding to inequity within the conservation sector. This paper focuses on spatial, or geographic, barriers as one factor determining the accessibility of conservation services. While the case study focuses on the conservation and management of collections of cultural material in Australia, the methodology is globally relevant for advancing the equitable distribution of heritage and conservation resources according to need. Using a statistical analysis of the spatial distribution of 1323 local heritage conservation projects that have been funded by the National Library of Australia’s Community Heritage Grants Program from 1994 to 2017, this study provides a measure of the spatial equality of conservation in Australia. Spatial distribution analysis indicates that the majority of projects funded are located in major cities, with fewer projects funded in regional, remote and very remote areas. An ‘access relative to need’ approach is proposed to counter the current centralisation of the conservation industry. Of particular relevance for international readers is the potential for this methodology to frame studies of the impacts on heritage resulting from climate change and extreme weather events.     

The Tenth Conference of the International Committee for the Conservation of Mosaics. Conservation: An Act of Discovery

Abstract

The Herculaneum Conservation Project has approached the conservation of a large-scale archaeological site (Herculaneum, Italy) suffering widespread forms of decay in two different ways: 1) with a site-wide campaign addressing conservation problems in areas most at risk and 2) with a case-study project for one urban block (Insula Orientalis I ) exploring some of the complex conservation challenges in more detail. One of these challenges is how to approach the repair of existing roofing and how to design new forms of protective shelter for those spaces that have never been covered. Short-, mid- and long-term solutions for the repair and substitution of existing roofing are being tested as part of the site-wide campaign, while in the case-study area more enduring solutions (new mid- and long-term) for new shelters are being trialled.     

CORRESPONDENCE AND DISCRIMINANT ANALYSES OF SAND AND SAND TEMPER COMPOSITIONS,TONTO BASIN,ARIZONA*

Geologists use petrographic modal analysis to relate fluvial sand composition to source rock composition, thus establishing provenance. Archaeologists seeking to establish provenance of sand temper in pottery can use similar petrographic methods, but their finer scale of investigation requires more precise statistical tools than those employed by geologists. A quantitative method for performing that task is presented. It utilizes correspondence analysis and discriminant analysis of logratio transformed point‐count data to define petrofacies, or sand temper resource procurement zones. The procedure is illustrated with sand and sand‐tempered sherd samples collected from the Tonto Basin, central Arizona; temporal trends in utilitarian ceramic production c. AD 100–1350 are reviewed.     

MULTIVARIATE MIXTURE OF NORMALS WITH UNKNOWN NUMBER OF COMPONENTS: AN APPLICATION TO CLUSTER NEOLITHIC CERAMICS FROM AEGEAN AND ASIA MINOR USING PORTABLE XRF*

Multivariate techniques and especially cluster analysis have been commonly used in archaeometry. Exploratory and model‐based techniques of clustering have been applied to geochemical (continuous) data of archaeological artefacts for provenance studies. Model‐based clustering techniques such as classification maximum likelihood and mixture maximum likelihood have been used to a lesser extent in this context and, although they seem to be suitable for such data, they either present practical difficulties—such as high dimensionality of the data—or their performance gives no evidence that they are superior to standard methods. In this paper standard statistical methods (hierarchical clustering, principal components analysis) and the recently developed model‐based multivariate mixture of normals with an unknown number of components, are applied and compared. The data set provides chemical compositions of 188 ceramic samples derived from the Aegean islands and surrounding areas.     

Complications and Effectiveness of In Situ Preservation Methods for Underwater Cultural Heritage Sites

Abstract

Underwater Cultural Heritage (UCH) as an outstanding division of the cultural heritage of humanity appears to be crucial and complicated when more general issues regarding preservation and conservation are raised. The essence of in situ preservation should be equally discussable for any kind of archaeological remains; on land or underwater.

There is a long history of different methods and concepts of intervention in a variety of sub-aquatic archaeological sites; from shipwrecks to submerged settlements. This paper will present an introduction to different techniques and theories of preservation and conservation of underwater cultural and archaeological sites since this kind of heritage has scientifically been explored and studied. A range of different preservation methodologies, from total or partial transference inland, to preservation underwater, will be compared; the advantages and disadvantages of each option will be highlighted. Different examples of international best practices will be illustrated. Different types of in situ conservation/protection will be explained and categorized. Furthermore, there will be a focus on the UNESCO Convention of 2001 on Conservation and Preservation of UCH, where the in situ conservation option has been recommended.

Moreover, the technical issue for preservation of UCH sites, either in situ or after displacement, will be explained. The implication of relocation for different sorts of sites and materials will be argued; for example, cases where some sites, such as shipwrecks, would more easily be displaced compared with submerged settlements, villages, or ports.

Finally, by stressing that the state of ‘being underwater’ makes many sites qualified to be regarded as UCH, the in situ preservation approach will prevail that this state is maintained.     

Antifungal activity of some plant extracts and essential oils against fungi-infested organic archaeological artefacts

The determination of the antifungal activities of nine kinds of powdered plant extracts and five essential oils was studied in vitro against four of the most common fungal species (Aspergillus flavus, A. versicolor, Penicillium sp. and P. purpurogenum), which were isolated from different organic materials from archaeological artefacts such as papyrus and linen. The essential oils showed greater efficacy than the powdered plant extracts, where thyme and lemongrass oils were the most potent. Also, the minimum inhibitory concentration and minimum fungicidal concentration of these oils were determined. Furthermore, their chemical components were identified using gas chromatography-mass spectrometry (GC-MS) analysis. In vivo, studies were performed using biodeteriorated samples for applying treatment, in which the microbiological test revealed that both oils can eradicate both tested fungi completely after exposure time, ranging from two weeks for papyrus samples to 14 weeks for linen. A scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and colorimeter were used to assess the treatment process, leading to the final results, which suggest that the essential oils could be useful sources of fungicidal preparations for the disinfection of biodeteriorated linen and papyrus artefacts. Nevertheless, further studies are strongly recommended to introduce these sources into practical use in preventive conservation.     

Eco-Archaeometry: Interdisciplinary Applications in Egypt

Abstract

One of the problems currently faced by modern society is the worldwide catastrophic deterioration of archaeological and cultural sites directly exposed to the action of the environment. Frequently, it has proved difficult to identify the processes responsible for these deteriorations, which are often the result of an abrupt change in site specific environmental conditions. To understand them a broad interdisciplinary approach is needed, and consequently, a substantial input from several disciplines, such as archaeology and archaeometric, environmental and conservation sciences, is necessary. Such interaction is particularly necessary on a basic research level, and can best be achieved if the relevant disciplines are drawn together a priori on equal footing into a complementary effort in eco-archaeometry. The primary goal of eco-archaeometry is to identify and quantify physicochemical processes which cause the deterioration of ancient cultural patrimony. Its findings are essential prerequisites for the development of optimum, safe methods for conservation and preservation of ancient monuments. Some examples of the eco-archaeometric approach in Egypt are summarised and it is demonstrated that without an interdisciplinary approach such studies would not have been successful.     

Identities in the making: conservation,gender and race in the Maya Biosphere Reserve,Guatemala

This article examines how the daily discourses, practices, and performances of conservation projects are instrumental in mapping ways of life that are gendered and racialized. With the goal of bringing a feminist approach to the study of conservation, I present an ethnographic account of identities‐in‐the‐making in three conservation encounters in the Maya Biosphere Reserve, a protected area in northern Guatemala. In the first two encounters, I examine the ways in which gender and race are constituted in the relations between the Women’s Group for the Rescue of Itza’ Medicinal Plants and a United States‐based international environmental non‐governmental organization. The third encounter highlights the relations between the Women’s Group and myself, the researcher, to analyze how social‐science, through methods such as ethnography, is also implicated in (re)configuring social identities.     

COMPOSITION AND ORIGIN OF IAPYGIAN POTTERY FROM ROCA VECCHIA,ITALY

We have studied 35 samples of fragments of ceramic containers dated between the eleventh and the eighth centuries BC, found at the archaeological site of Roca Vecchia, some 20 km from Lecce along the Adriatic (Salentine) coastline. Analysis of the elemental composition of the finds has been performed by means of atomic emission spectroscopy in plasma and the results obtained have been treated with diverse multivariate statistical techniques. Except for some minor differences, the statistical analysis confirms the grouping structures indicated by typological and stylistic evaluations of the samples, in accordance with the validity of the above methods.     

A programme for the conservation of architectural plasters in earthen ruins in the American Southwest: Fort Union National Monument,New Mexico,USA

Abstract

Plasters constitute an important component of many ruined architectural and archaeological sites. Methods for their in situ conservation have lagged far behind the field treatment of other materials due to their ephemeral nature and the lack of programmatic laboratory and field research. A preservation strategy involving documentation, stabilization, interpretation and maintenance offers a methodological approach adaptable to most contexts. A pilot conservation programme is described for the stabilization and interpretation of the lime plasters within the nineteenth-century adobe ruins of Fort Union National Monument in New Mexico. Methods of documentation, emergency stabilization, injection hydraulic lime grouting and mortar repairs are described.     

Transitions in the Ottoman Waqf’s traditional building upkeep and maintenance system in Cyprus during the British colonial era (1878–1960) and the emergence of selective architectural conservation practices

How did the Waqf, a widespread Islamic historic institution in the non-Western world which promoted traditional building upkeep and maintenance systems, cope with the emerging architectural conservation understandings of the modern era? How did colonial transfers of knowledge, expertise and political considerations influence these systems? The present study explores these questions by examining the case of the Ottoman Waqf (Evkaf) institution in Cyprus. By collecting and analysing archival evidence on conservation projects, initiated during the British colonial period between 1878 and 1960, a model framework of initiation, authorisation and implementation processes of the upkeep of the Waqf maintained properties has been identified. This framework has been used to show the transitional role of the colonial influence at different stages, which finally led to the dissolution of the Waqf system’s sustainable elements, and initiated the emergence of selective architectural conservation practices. By shifting the focus of conservation discourses to look specifically into the background dynamics of the institutional practice, a new argument has been developed. This revealed how heritage conservation practices are negotiated with the existing institutions and how they are transferred and/or transformed at different levels of institutional governance.     

MATHEMATICS,STATISTICS AND ARCHAEOMETRY: THE PAST 50 YEARS OR SO*

This review of developments in the use of mathematics and statistics in archaeometry over the past 50 years is partial, personal and ‘broad‐brush’. The view is expressed that it is in the past 30 years or so that the major developments have taken place. The view is also expressed that, with the exception of methods for analysing radiocarbon dates and increased computational power, mathematical and statistical methods that are currently used, and found to be useful in widespread areas of application such as provenance studies, don't differ fundamentally from what was being done 30 years ago.     

Geographic information system‐based edge effect correction for Ripley's K‐function under irregular boundaries

Ripley's K‐function is a test to detect geographically distributed patterns occurring across spatial scales. Initially, it assumed infinitely continuous planar space, but in reality, any geographic distribution occurs in a bounded region. Hence, the edge problem must be solved in the application of Ripley's K‐function. Traditionally, three basic edge correction methods were designed for regular study plots because of simplified geometric computation: the Ripley circumference, buffer zone, and toroidal methods. For an irregular‐shaped study region, a geographic information system (GIS) is needed to support geometric calculation of complex shapes. The Ripley circumference method was originally implemented by Haase and has been modified into a Python program in a GIS environment via Monte Carlo simulation (hereafter, the Ripley–Haase and Ripley–GIS methods). The results show that in terms of the statistical powers of clustering detection for irregular boundaries, the Ripley–GIS method is the most stable, followed by the buffer zone, toroidal, and Ripley–Haase methods. After edge effects of irregular boundaries have been eliminated, Ripley's K‐function is used to estimate the degree of spatial clustering of cities in a given territory, and in this paper, we demonstrate that by reference to the relationship between urban spatial structure and economic growth in China.     

A critical physical geography of no-till agriculture: Linking degraded environmental quality to conservation policies in an Oregon watershed

A variety of agricultural conservation trends have gained and lost favour throughout the years, with farm bills in the United States often influencing which conservation practices are implemented. This paper explores the consequences of a set of conservation techniques loosely defined as “no-till agriculture,” focusing on their implementation and adoption since 1985, at which point such approaches began to be explicitly encouraged under US Farm Bill soil conservation mandates. We begin by noting a core contradiction that has characterized these approaches in the Fifteenmile Watershed of Wasco County, Oregon, where despite high rates of farmer enrollment in no-till programs, both no-till agriculture and sustained tillage have led to the increased use of herbicides and sustained sediment runoff. Using a critical physical geography framework that integrates intensive physical field data collection, spatial analysis, social surveys, and interviews, we address the biophysical and social factors collectively driving changes in herbicide use and variable erosion estimates. We draw particular attention to how farm bill support for no-till has enrolled farmers in a vaguely defined and underregulated conservation practice that may ultimately undermine environmental quality.