Presentation HESTIA colloquium Oxford 2 July online

July 5, 2010

On 2 July I gave a presentation at the HESTIA colloquium in Oxford. Project HESTIA aims to explore the perception of space as it is reflected in Herodotus’ Histories, through novel digital approaches including network analysis. Read more on the project here.
You can find my presentation slides on the bibliography page. Here is the abstract:


Understanding Roman table ware distributions in the Mediterranean: an exploratory and confirmatory network analysis of the ICRATES database
Roman table ware distributions are traditionally explored through their presence in specific places and visualised as dots on a map. As such they seem to represent distinct entities that do not relate, other than in their relative proximity. This paper challenges an exclusively geographical perspective by proposing a networks approach for exploring ceramic distributions. It states that it is equally informing to explore the dynamics between physical and relational space. There can be no doubt that places and people in the past were connected to each other, and this paper will explore to what extent this connectivity is reflected in the relationships between ceramic data. In order to understand the nature of this connectivity it is necessary to explore the structure of pottery distributions.
This paper aims at addressing the following issues:
To what extent can the relationships between table ware sherds inform us of processes that led to their distribution as we know it?
How can topological and geographical networks complement each other in understanding such processes?
The ICRATES database of table wares from the Roman East (Prof. Jeroen Poblome, Katholieke Universiteit Leuven), containing exhaustive information on over 20,000 published sherds, will allow for these issues to be tested. Firstly, this paper will illustrate how analysing ceramic distributions as networks of interactions can help to identify the general structure and local patterns in a complex dataset. Secondly, the potential of network analysis for testing a geographical hypothesis will be evaluated. The results of both types of analyses will be confronted to validate the geographical hypothesis with ceramic data and to explain some of the patterns that emerged from the topological approach. As such, this paper aims to start discussions on comparing archaeological and historical networks generated from different data types.


Presentation Southampton 18 March online

March 23, 2010

I just added a link to download my presentation at Southampton on 18 March on the bibliography page. The text to accompany the presentation is the article in Oxford Journal of Archaeology and my MSc dissertation. Thanks to all who attended and contributed to the interesting discussion!


Presentation Southampton 18 March

March 12, 2010

On 18 March I will present my recent work on archaeological network analysis at the University of Southampton in the Computer Applications in Archaeology seminar series. Read the announcement here. This discussion session will focus on understanding pottery distributions by using network analysis, using the ICRATES database of table ware sherds from the Roman East. I will present networks of co-present ceramic forms on sites, and I will test a geographical hypothesis on Mediterranean trade routes using distance-based networks. Moreover, I will reveal a completely new network type that draws on the results of the previous two and emphasises the chronological aspect. This third network type will explore the gradual adoption of table wares in sites and look for factors that influenced this adoption.
You can read up on these network types in my dissertation, available from the bibliography page. The presentation itself will be available next week.
For those in the vicinity of Southampton on 18 March: its in the archaeology department from 12 to 1


CAA UK presentation online

March 11, 2010

I just added a link to download my presentation at CAA UK 2010 on the bibliography page. The text to accompany the presentation is the article in Oxford Journal of Archaeology.


CAA UK

February 16, 2010

On Saturday 20 February I will present a paper at Computer Applications in Archaeology UK chapter conference at University College London. The talk is based on a paper that will appear in one of the forthcoming issues of Oxford Journal of Archaeology (the pre-published version is available on the bibliography page). My aim will be to convince the audience that current archaeological applications of network analysis are based on an incomplete and sometimes uncritical adoption of network principles from other disciplines, and that the need exists to work towards an explicitly archaeological network analysis. An abstract is included below.

Do have a look at the CAA UK website, I’m very much looking forward to all the other talks.

ABSTRACT

In recent years network analysis has been applied in archaeological research to examine the structure of archaeological relationships of whatever sort. A first generation of archaeological applications of network analysis has succeeded in providing an innovative view of long discussed issues by stressing the importance of exploring relationships between objects/people/data directly. However, these archaeological applications share a number of issues concerning:

  • the role of archaeological data in networks
  • the diversity of network structures, their consequences and their interpretation
  • the critical use of quantitative tools
  • the influence of other disciplines, especially sociology

This paper concerns a deconstruction of past archaeological methods for examining networks. Through a case-study of Roman table wares in the Eastern Mediterranean, it will highlight a number of issues with network analysis as a method for archaeology. It urges caution with the uncritical application of network analysis methods developed in other disciplines and applied to archaeology. However, it stresses the potential benefits of network analysis for the archaeological discipline and acknowledges the need for developing a specifically archaeological network analysis, which should be based on relational thinking and can be expanded with an archaeological toolset for quantitative analysis.


MSc dissertation finished

October 26, 2009

My dissertation concerning the archaeological application of network analysis is finally finished. In this post you will find an abstract of the completed work. The project is far from over though. I will continue exploring and writing on archaeological network analysis through a number of different projects. So stay in touch and feel free to contact me if you have questions or if you are interested to collaborate.
The full dissertation is available on Scribd, and is embedded at the bottom of this post.
The project’s results can be seen on the project’s website.

ABSTRACT
New and continually evolving digital technologies allow archaeologists to study ever larger volumes of information to formulate and support their interpretations of the past. A downside to this trend, however, is that the accumulation of archaeological data from different sources often leads to heterogeneous and complex datasets. Archaeologists should be aware that the data they combine results from a series of decisions taken in different stages of the object’s life cycle (e.g. initial distribution, re-use) as well as after their deposition (e.g. site selection, publication). Given the wide range of processes that lead to the creation of large and complex archaeological datasets, initial data exploration is invaluable. We believe that these processes are reflected in the relationships between archaeological data. It is our aim to develop a method for exploring these relationships, in order to understand the complexity of archaeological datasets. It is argued that network analysis can serve this purpose. To test this method, it will be applied to a large and complex database of tablewares from the Roman East. Firstly, it will be illustrated how analyzing archaeological data as networks of meaningful interactions can help to identify the general structure and local patterns in a complex dataset. Secondly, the potential of network analysis for testing a geographical hypothesis will be evaluated.

View this document on Scribd

Method update: beta-skeletons

July 21, 2009

This second update of the project’s method concerns the distance networks based on beta-skeletons described in an earlier blog post. We mentioned that the reconstruction of ancient trade routes is extremely complex as a number of variables should be taken into account, so our best bet is to focus on one parameter that might have been influential in determining trade routes. Using beta-skeletons and graph theory we will investigate whether the distance between centre of production and site of deposition is reflected in the ceramic evidence and whether it significantly influenced the selection of trade routes.

Although we mentioned in a previous post that the beta-skeleton would be compared with a reconstruction of trade routes based on the shortest path for every sherd from centre of production to site of deposition over this beta-skeleton, we now have to confess that this is nonsense as we would compare the beta-skeleton with a slightly altered version of itself that is based on a large number of assumptions concerning the intermediary sites. We realized that these shortest paths actually contain the hypothesis that we are testing, as they represent trade routes based on the ceramic evidence in which distance surpasses all other factors in importance.

To create such a network of trade routes we will make a beta-skeleton in which every site has at least one connection, so that all of them would be reachable. This will be done in ArcGIS with a beta-skeleton calculator programmed by dr. Graeme Earl, applied to all the sites in the database and their geographical coordinates. For every sherd the shortest path in geographical distance from centre of production to centre of deposition over this beta-skeleton will be calculated in pajek (although this can be done in ArcGIS, pajek is able to calculate geographical as well as graph theoretical shortest paths). Edge value will represent the number of sherds passing between two sites and edges with a value of zero will be discarded.

At this point we have a reconstruction of the trade routes over which the vessels would have been transported if the distance between start and ending point would have been the only factor taken into consideration by their transporters. This network embodies the hypothesis we want to test, which can be done by comparing it to another network visualisation of ceramic evidence. The networks of co-presence described in the previous post will provide this basis for comparison, as they do not contain any assumptions of their own (before their analysis that is).

Now, there is an obvious danger of comparing things with different meanings, so we need to be very clear of what aspects of both networks will be used for comparison. We will focus on a couple of phenomena that we think are represented in both types of networks: bridges and centrality.

A bridge is a line whose removal increases the number of components in the network (de Nooy et.al. 2005: 140). In our networks of co-presence a bridge is a site that forms the connection between two different groups of distribution networks. Such a site should play an important role in dispersing information on the pottery market as it is linked in with highly differing networks, but does not necessarily play a central role in the entire network. On the distance network these sites should play a similar role in connecting different distribution networks, in order for the hypothesis to be valid.

Sites belonging to the centre of a pottery distribution network can be easily reached by new pottery forms from diverse producing centres, they are central to the communications network of the pottery trade as it is represented in the ceramic evidence. This is true for both our shortest path network and our co-presence network, and can be measured using the closeness centrality method: sites are central in distribution networks if their graph theoretical distance to all other sites is minimal. In network terms: the closeness centrality of a vertex is the number of other vertices divided by the sum of all distances between the vertex and all others (de Nooy et.al. 2005: 127). Although this method will provide comparable numerical results (a score between 1 and 0), we will not compare these absolute values. Rather, we will focus on seeing whether sites that are central (or not) in our co-presence network are also central (or not) in our shortest path network.

Pairs of contemporary networks of both types will be compared using these methods in order to provide an answer to our hypothesis “was distance a significant factor in selecting trade routes?”