A STATISTICAL APPROACH TO THE CALIBRATION OF FLOATING TREE-RING CHRONOLOGIES USING RADIOCARBON DATES

The bristlecone pine tree-ring calibration of radiocarbon dates, while necessitating changes of up to 700 years in Holocene chronology before 1000 b.c. , offers possibilities of very accurate dating when ¹⁴C determinations from floating tree-ring chronologies are utilized. A statistical approach assuming linear regression is developed and used to position the floating tree-ring chronologies at Swiss neolithic sites, using radiocarbon dates published by Ferguson, Huber and Suess and by Suess. The statistical method gives objective estimated dates with estimates of error related, in a consistent and explicit manner, to the inherent inaccuracies of the radiocarbon dates. Most of the method may readily be tested by standard statistical procedures. For the particular cases considered the assumptions of linearity and parallelism are investigated, and the precision of the estimated dates is comparable with that claimed by Suess and his co-workers. A precise calibration is thus possible without utilizing the short-term fluctuations in the Suess calibration curve. The analysis, while avoiding some assumptions of Suess and his collaborators, offers an explicit procedure for establishing controlled teleconnections with the Ferguson dendrochronology, and supports their emphasis on the importance of radiocarbon dates from floating tree-ring sequences for the construction of precise prehistoric chronologies.     

A NEW APPROACH TO MODELING THE IMPACT OF DISRUPTIVE EVENTS

This paper develops a new methodology to predict the interregional and interindustry impacts of disruptive events. We model the reactions of economic agents by minimizing the information gain between the pre‐ and postevent pattern of economic transactions. The resulting nonlinear program reproduces, as it should, the pre‐event market equilibrium. The methodology is tested further by means of a comparison of this base scenario with two regional production shock scenarios and two interregional trade shock scenarios. The outcomes show a plausible combination of partially compensating demand, supply, and spatial substitution effects, which justifies the further development, testing, and application of this new approach.     

A SYSTEMATIC APPROACH TO THE DEFINITION OF SOURCES OF RAW MATERIAL

This paper argues the importance of the contribution that multivariate statistical techniques can make to the analysis of data from trace element characterization of sources of raw material and of artefacts. A threephase analysis is outlined: for the delimitation of sources of the raw material; the representation of the interrelationships of these sources; and the systematic and explicit allocation of artefactual material within the available universe of source groups. A model is developed using obsidian from New Zealand sources and presented as an example of the method.     

TRISANTONA RIVERS: A LANDSCAPE APPROACH TO THE INTERPRETATION OF RIVER NAMES

Summary. Etymological conclusions from river names are notoriously inconclusive. An alternative approach is to explore possible consistencies in the character or use of rivers with names of similar origin in a given area. This paper examines examples of the British river-name Trisantona (Trent, Tarrant, etc.), and pursues suggestions that the name indicates a thoroughfare or route used in early times.     

THE DOUBLE-AXE: A CONTEXTUAL APPROACH TO THE UNDERSTANDING OF A CRETAN SYMBOL IN THE NEOPALATIAL PERIOD

The Double-Axe has always been considered as one of the most important religious symbols in Minoan Crete. This paper reassesses the significance of the Double-Axe and puts forward a new interpretation for it. It recognizes the great potential for change in symbolic meanings during the Bronze Age and seeks to understand the Double-Axe in as narrow a period as is realistically possible by filtering out evidence from other periods. Central to the argument is the principle that the meaning of symbols is contextually dependent. It builds, therefore, a new interpretation of the Double-Axe on the basis of as wide a range of contextual associations as possible, both within iconographic sources and in the wider material record. From these contextual associations, it suggests that in the Neopalatial period the Double-Axe was a symbol primarily associated with a social group which exercised power in the economic, military and religious realms and that it became a solely religious symbol only later.     

THE BAYESIAN APPROACH TO THE INTERPRETATION OF ARCHAEOLOGICAL DATA

Archaeologists are increasingly becoming aware of an approach to data investigation known as Bayesian statistics. In this paper we outline both the philosophical and statistical background to the approach. We show that it provides a logical and coherent framework in which to make inferences on the basis of both data and a priori expert knowledge. We note that adoption of the Bayesian framework is particularly timely since there have been recent dramatic developments in numerical methods which mean that a number of previous implementation problems have now been solved. As a result, many questions of archaeological interest, which require the use of complex statistical models, are being investigated using this methodology. We use a variety of recently published examples from a range of archaeological areas to illustrate the type of questions that can be answered and the nature of the methodologies used, and we make comparisons with the results obtained using more traditional statistical techniques.     

ARTIFICIAL NEURAL NETWORKS: A NEW APPROACH TO MODELING INTERREGIONAL TELECOMMUNICATION FLOWS*

ABSTRACT. During the last thirty years there has been much research effort in regional science devoted to modeling interactions over geographic space. Theoretical approaches for studying these phenomena have been modified considerably. This paper suggests a new modeling approach, based upon a general nested sigmoid neural network model. Its feasibility is illustrated in the context of modeling interregional telecommunication traffic in Austria, and its performance is evaluated in comparison with the classical regression approach of the gravity type. The application of this neural network approach may be viewed as a three-stage process. The first stage refers to the identification of an appropriate network from the family of two-layered feedforward networks with 3 input nodes, one layer of (sigmoidal) intermediate nodes and one (sigmoidal) output node (logistic activation function). There is no general procedure to address this problem. We solved this issue experimentally. The input-output dimensions have been chosen in order to make the comparison with the gravity model as close as possible. The second stage involves the estimation of the network parameters of the selected neural network model. This is performed via the adaptive setting of the network parameters (training, estimation) by means of the application of a least mean squared error goal and the error back propagating technique, a recursive learning procedure using a gradient search to minimize the error goal. Particular emphasis is laid on the sensitivity of the network performance to the choice of the initial network parameters, as well as on the problem of overfitting. The final stage of applying the neural network approach refers to the testing of the interregional teletraffic flows predicted. Prediction quality is analyzed by means of two performance measures, average relative variance and the coefficient of determination, as well as by the use of residual analysis. The analysis shows that the neural network model approach outperforms the classical regression approach to modeling telecommunication traffic in Austria.