I've been spending most of my discretionary work time over the last couple of weeks grinding through the process of getting my computer models up and running again. The main challenges have involved converting my models from Repast J to Repast Simphony. While the Java components are the same, the "world" of the models is structured differently in Simphony. So I've had to try to figure out how to re-connect the various parts of the models using what Simphony calls "context."  I can't yet say I fully understand how "context" works, but I got my ForagerNet3_Demography_V3 (FN3_D_V3) model up and running by trial and error and looking at examples of code from other models.   

Since I haven't figured out to configure the model to use the batch run GUI (I haven't even been able to find it yet, although it apparently exists somewhere in Eclipse), I've been using a primitive parameters file to do batch runs. As I wrote on Friday, these batches would throw an "Out of Memory" error and freeze up around the fortieth run. That suggested some kind of memory leak where object produced during a run were not being deleted before the next run. The gradual accumulation of unused objects eats up the memory until there isn't any left to use to run the model, then it dies.

After going through the code several times and trying a bunch of options, I think I finally found the culprit(s) and made the corrections.  I set the model to run 500 times a couple of days ago, and things seemed to be chugging along just fine (when I got to my office this morning it was at run number 720-something, so clearly I didn't have the "stop" command implemented correctly).  Anyway, I've  now got a batch of new data that I can compare with data produced by the model when it was implemented in Repast J.  The figure below compares old model data (left) with new model data (right).  It is gratifying to see the model is behaving the same.

The data on the left are from a paper of mine ("The Sensitivity of Demographic Characteristics to the Strength of the Population Stabilizing Mechanism in a Model Hunter-Gatherer System") that will be published in an upcoming volume titled Uncertainty and Sensitivity Analysis in Archaeological Computational Modeling (edited by Marieka Brouwer Burg, J. H. M. Peeters, and William A. Lovis; Springer).

I'm happy that this model is back in business. I'll do some more testing to make certain everything is working, then I'll clean up the code and make it available on this website and under my profile at OpenABM. I plan to use this model for some work on the demographic viability of small populations and, perhaps, to push ahead with exploring demography, mortality, and fertility during the Middle Paleolithic. 

I've started a new page to store links to online sources of radiocarbon data and references for published compilations. As I discussed briefly in this blog post, I'm interested in a assembling a pan-Eastern Woodlands radiocarbon dataset that can be used to evaluate the idea that there was an abandonment of the Southeast at the end of the Early Archaic period.

The page has links to several datasets (such as CARD and the files posted at PIDBA) that include dates from across the Eastern Woodlands. I've also started a section listing sources by state, which is the scale at which many compilations are created. Thanks to Stuart Fiedel for pointing me in the direction of several compilations from the Atlantic coast. I stumbled across data from the Georgia Coastal Plain, a Tennessee dataset, and a Louisiana database and have provided links to those.  

Conspicuously absent so far are compiled datasets from South Carolina, Alabama, Mississippi, Illinois, Indiana, and Pennsylvania. Presuming that a South Carolina dataset does not already exist, it seems that the responsibility for assembling one would logically be mine. I'm hoping some of you out there can let me know about datasets that will help fill in the gaps and perhaps update some of the older compilations.

At some point, I'll combine all the existing data together and make it all available. It shouldn't be that tough but it will take a little time. It will be a matter of creating a database with the necessary fields and then adding existing data either electronically (i.e., in cases where data are already available electronically) or manually.  The less manual data entry, the better.

​Please leave a comment here if you know of sources that I haven't yet included.

I've been hard at work rolling a boulder up the Repast Simphony learning curve.  Computer modeling is a basic element of my three-headed "Shovels, Collections, and Code" research agenda. The other two are on track: I'm planning future survey/excavations at a natural levee system that appears to contain buried Archaic components, and I've started my collections work with an ambitious data-gathering effort oriented toward understanding the Kirk Horizon.  The computer modeling part of my work is an important part of building an interpretive framework that allows us to integrate the small-scale behaviors we can document at individual sites with the large-scale patterns we can describe through pan-regional collections work.  More on that later.

Call me crazy, but I find writing and debugging computer code to be relaxing.  It can be frustrating, of course, when you can't figure out the source of some problem or error, but overall the process of building and tuning a model is engaging and strangely soothing. The parts make sense, represent something, and work together. And there are rewards for elegant design. It's fun. During my dissertation work I sometimes had the luxury of taking full days (not 9-to-5 days, but 24 hour days) to focus on uninterrupted programming.  Those days are gone, but I still find myself enjoying the times when I can block out a few hours, close my door, and get into the code.

The rest of the world doesn't stop, however.  So I have a few things I wanted to briefly talk about today.
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Amazing Tales of a Fringe Utopia in Northeast Illinois

A reader of this blog emailed me some links to material that, for all I know, is familiar ground to those who closely watch "fringe" theorists.  I had never heard of E. P. Grondine's manuscript He Walked Among Us, however, so I presume that others also have not.  The work (available in three parts here), details the history, philosophy, and inter-personal interactions of "fringe" figures (including David Hatcher Childress) in a small town in northeastern Illinois. Thus far I have only skimmed through parts of it (it will go on my summer reading list).  Check it out and see what you think. 

I don't know E. P. Grondine and am not yet very familiar with his work. He has commented on this blog at least once.
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Plugging Memory Leaks

I've succeeded in getting one of my models (ForagerNet3_Demography_V3) operational in Repast Simphony. Repast Simphony operates a little bit differently than Repast J (the platform that I used to write the model), so I had to learn something about those differences, write some new code, and re-configure some other sections of the code.  Though I've still got some testing to do to make sure the model is behaving the same (i.e., it's doing the same thing it did before the conversion), everything seems to be working within the model itself.

The issue I'm trying to solve now is getting the model to run in batch mode.  Running a model in batch mode means that the computer performs a series of model runs (a "batch") automatically.  One of the great benefits of computational modeling is that you can do systematic experiments and determine cause and effect. You can hold everything about the model constant except for the value of single parameter, for example, and see how changes in that parameter affect the outcomes. You can run the model as many times as you want -- tens, hundreds, or thousands -- to flesh out those cause-effect relationships. Running the model in batch mode automates that process.  Ideally, I can start a batch running on Friday afternoon and return to my office on Monday morning with a large dataset ready to analyze.

There is apparently a built in batch configuration in Repast Simphony, but for some reason I haven't yet been able to get to it in the software. Maybe I need to reinstall.  For the time being, I've been using a simple little parameters file that just tells the software how many iterations of the model to perform and what random seed to use.  The model runs for the first 40-50 runs before throwing an "Out of Memory" error and locking everything up. It seems to run slower and slower with each iteration, which suggests to me there is a memory leak somewhere in my code. The model creates a bunch of objects (people, households, social links between people) during each run. Each of those uses memory. At the end of each run, all the object associated with that run should be tossed out to free up all the memory for the next run (when the model resets and starts fresh).  If some of the objects are "leaking through" and being retained in the memory, the progressive accumulation of those unused objects will eat more and more memory until there's none left.  I'm pretty sure I've got the model tossing all the people, households, and links (the three agent classes) out, so it may have something to do with copies of the spatial world and/or what's called the "context."  The structure of the "world" in Repast Simphony is different from that in Repast J, so I need to figure out how to make sure I'm getting rid of all the unused parts between each model run. That's my goal for today. Hopefully I can find and plug the memory leak and set my computer to work for me over the weekend.
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The "Sword Report"

I still haven't been able to muster the combination of time and interest to read through J. Hutton Pulitzer's "sword report." What I know about the contents of the report I know from comments on Facebook pages (e.g., The Fraudulent Archaeology Wall of Shame and Fake Hercules Swords), this blog post from last week, and Jason Colavito's post about the report. My two main impressions are these (please correct me if I'm wrong):
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The report contains no new information about the alleged "Roman sword from Nova Scotia." Pulitzer does not provide his XRF data that he claimed proved the sword was a "100% confirmed" Roman artifact. He spent months crowing about his XRF results, and, in fact, said he would release them "the next day" after Brosseau's results were aired on television. He has not done that. Why?  Remember when he said the exposed brass on the sword was actually gold? Whatever happened to that claim?

The report is an argument against Brosseau's interpretations, not her results.  Pulitzer seems to have abandoned the argument that his XRF results are correct and Brosseau's results are wrong, and is arguing that the metals identified by Brosseau are consistent with those produced by Romans.  He actually made this pivot some time ago (I wrote about it back in January). Sometime after Brosseau's results were aired, he decided that he had a better chance making a case for the antiquity of the sword based on Brosseau's results (which are well-explained and documented) than his own (let us never speak of those XRF results again?).  Apparently, the "case" for the Roman antiquity of brass with 35% zinc is based on the same sleight-of-hand he tried in January (see this post) with the added puffery of 70+ pages lifted more-or-less directly from this online study by David Dungworth.   Here is a direct quote from that study:

An Invitation for The Walking Dead to Enjoy Springtime in South Carolina

The Walking Dead is my favorite television show.  The program has had its ups and downs, but I think this season is pretty strong and I'm enjoying it. I'm a couple of episodes behind right now, so don't spoil it for me.

This week, Disney and Marvel warned Georgia Governor Nathan Deal that they will stop filming in the state if he signs a so-called "religious liberty" bill that many say will legalize anti-gay discrimination (here's the story in The Washington Post).  

I applaud Disney and Marvel for their stance, and hope that AMC follows suit and moves the filming of The Walking Dead out of northern Georgia. Given what's going on in North Carolina right now, the logical choice is to put the show in South Carolina.  There are signs this state is moving in the right direction (e.g., the removal of the Confederate flag last summer), and your business would be a nice encouragement. Having traveled up and down I-20 and 301 a few times now, I can tell you that you won't have any difficulty finding good locations for filming. You can enjoy the palmettos, azaleas, crepe myrtle, and Carolina wrens. We have some room at our house, so I can provide accommodations for at least two cast members (Glen and Maggie? Carol?).

Just think it over. You don't have to answer now. If you can't make it here this spring the flowers will still be blooming all year round. And there are butterflies.

This is just a quick post to commemorate the progress I've made this week in getting my main agent-based models (ABM) to work in Repast Simphony. I wrote all my model code in Repast J for my dissertation work and had access to help and some pretty powerful computing infrastructure while I was at the University of Michigan.  I had to largely put that part of my work aside after I was no longer a student. I didn't have full access to U of M's resources anymore, and I didn't have time with my job at Grand Valley anyway. So the modeling work has been on hold for a while.

One of my main goals this year (my first year at South Carolina) was to get my modeling work up and running again. I'm behind where I wanted to be at this point, but I'm happy to report that I've spent the week dealing with a lot of the main challenges (I think) of getting my Repast J code to work in Repast Simphony. The Java language stuff is the same, but there are some differences in how the models are structured (what controls what, etc.) and how you get it to schedule actions, put things in a spatial world, etc.  I've got the latest generation of my non-spatial model (ForagerNet3_Demography_V3) more-or-less up and running: people are forming households, reproducing, dying, forming and dissolving links to one another, etc., just like they used to. With those nuts and bolts operational again, I can move on to tinkering with model to streamline the code, figuring out batch mode, figuring out how to have it compile data outputs, and figuring out how to put the whole system back into a spatial framework again.  And then the fun really begins. But first: Miller Time.

The post about the Carolina Bays that I wrote a couple of weeks ago turned out to be relatively popular (as far as this webpage goes, anyway). Carolina bays are elliptical depressions of varying size that occur along the Atlantic Coastal Plain in a band extending from New Jersey to Florida.  Their limited geographic distribution and northwest-southeast orientation has given rise to many ideas about how these features were formed. Ongoing debate centers around the question of whether the bays formed as (1) the result of impacts associated with an extraterrestrial object (e.g., debris ejected by a comet strike in Saginaw Bay) or (2) through the actions of wind and water during the Pleistocene. Extraterrestrial or terrestrial?

A new paper by Chris Moore and colleagues (see full reference below) in Southeastern Geology provides more evidence that the bays were formed and modified over long periods of time by natural, terrestrial processes. You can read the paper for yourself here.

The evidence and analysis that Moore et al. present is a pretty strong argument against the idea that the bays were formed by a single event (i.e., an extraterrestrial impact).  I encourage you to take a look at the paper.  I'll just paste in a paragraph from their conclusion (pg. 168):

Moore, Christopher M., Mark J. Brooks, David J. Mallinson, Peter R. Parham, Andrew H. Ivester, and James K. Feathers. 2016. The Quaternary Evolution of Herndon Bay, a Carolina Bay on the Coastal Plain of North Carolina (USA): Implications for Paleoclimate and Oriented Lake Genesis.  Southeastern Geology 51(4): 145-171.

Addendum (3/18/2016):  Let's start over with the comments. Please keep comments on the topic of the blog post (Carolina bays) or I'll delete them.

I had some time today to upload some current Kirk Project files and do a little re-organization of the pages.  The main page is still located here, but I've split off some of the content that used to be on that page and created separate pages for datasets, a list of 3D models organized by state (so far they're all from South Carolina), embedded links to 3D models organized by ID number, and 2D images. There is nothing on the 2D image page yet, but my plan is to start adding images as I have time.

I've been steadily accumulating 3D models (there are 22 now that I've uploaded to Sketchfab). I still haven't started wrestling with them to extract usable morphometric data, but I've got a plan for a paper that will compare variability in the large, surface collected sample from Allendale County (South Carolina) to the variability present in smaller assemblages from excavated contexts (and shorter windows of time). One of those assemblages will be the Nipper Creek cache. Another (hopefully) will be the Kirk material from G. S. Lewis-East.  Hopefully I'll be able to get one or two more "narrow time window" assemblages.

In terms of data, I've produced an updated GIS map of the current sample (n=905). It now includes several points from Pennsylvania (donated by Bill Wagner). I've also provided a file of the metric data that I have for 699 of those points. As explained on the data page, the sample of points for which metric data are available is smaller than the larger Kirk sample because I did not measure all of the points during my dissertation work (some were too fragmentary) and I have not started generating linear measurements of the points I'm adding now.  

The linear measurements have alphabetic designations (A through I, as defined in this figure). I calculated them by digitizing landmarks using a freeware package, and it was kind of a pain in the butt.  I'm hoping to find a better software package than I used before, and I plan on adding some additional 2D dimensions/angles since I won't also be dealing with lanceolate points.

I did not produce 3D models of any of the points in my dissertation dataset, as I did not have access to the equipment to do that at the time. ​

I plan on adding a "Contributors" page soon. And I hope to start incorporating more data from external sources in the dataset. I've got lines on some data from Ohio, Tennessee, and a few other areas. I would love to start filling in Florida, Georgia, and North Carolina.

I've seen some recent chatter about Hutton Pulitzer's much-anticipated "FREE - Oak Island Roman Sword Scientific Method Report" that we've been promised, but I have yet to actually see a copy. Apparently at least one version of the report was made available for download a couple of days ago but the document couldn't be opened. Has anyone been able to download and open the report?

I signed up to get a copy of the sword report months ago but have yet to get an email about it. I'm curious as to what's in it, but that curiosity hasn't been strong enough to budge "look for sword report" from its position beneath about twenty other more important things on my to-do list.  If anyone has successfully viewed the report or knows where I can get a copy please let me know.

As I mentioned briefly in a post yesterday, I've become interested in looking into the evidence for an abandonment of large portions of the Southeast at the end of the Early Archaic period.  

This (2012) paper by Michael Faught and James Waggoner provides an example of how this could be done on a state-by-state basis.  Faught and Waggoner use multiple lines of evidence to evaluate the idea of a population discontinuity between the Early Archaic and Middle Archaic periods in Florida. One of the things they discuss is the presence of a radiocarbon data gap between about 9000 and 8000 radiocarbon years before present (RCYBP). They are able to identify that gap (which is consistent with a significant drop in or lack of population at the end of the Early Archaic using a dataset of 221 pre-5000 RCYBP radiocarbon dates from Florida. 

Assembly of radiocarbon datasets for states across the Eastern Woodlands would be really useful for seeing if there is a similar "gap" in other areas of the Southeast that correlates with technological and statigraphic discontinuities. It seems to me that small bifurcate points (e.g., LeCroy cluster) and/or larger lobed points (e.g., Rice Lobed cluster) are good candidates for marking a contraction or retreat of late Early Archaic hunter-gatherer populations.  While common in the Midwest, such points are absent (?) from Florida and present in only parts of South Carolina, Georgia, Alabama. 

I'm aware of the Kentucky, Ohio, West Virginia Radiocarbon Database published by Cultural Resource Analysts, Inc. I'm wondering if there are similar existing compilations (either print or electronic) for other eastern states, especially those south of the Ohio River. I've only spent a short amount of looking, but I haven't come across any yet. At the risk of being accused of being lazy, I thought I'd throw the question out there and see what turns up. I will be very surprised if radiocarbon compilations haven't been produced for many areas of the east, and it seems worthwhile to ask about existing resources (which may not yet be easily "discoverable" online) before I contemplate yet another large-scale data mining effort.  Please let me know if you can help.

Update (3/27/2016): I've created this "Eastern Woodlands Radiocarbon Compilation" page to store links and references to radiocarbon compilations.

I'm going to skip the usual discussion of how I wish I had more time to write, and go straight to the summary of things I would've written about if I had more time. I'm limiting myself to one paragraph per topic.

Abandonment of the Southeast During the Early Archaic

I finally finished reading Ken Sassaman's (2010) The Eastern Archaic, Historicized (previous posts here and here). I had a nice email exchange with Sassaman.  Reading his book has gotten me thinking about some new questions to ask of the Archaic record in the Eastern Woodlands.  The suggestion that a large part of the Southeast (south of the Ohio River) was abandoned or very thinly populated/used during the later part of the Early Archaic, connected to the scenario of a population influx during the Middle Archaic, is something that can be evaluated empirically by (I think) assembling data that we've already got on hand. The northward retreat of Early Archaic populations that seems to be marked by the distribution of bifurcate points in South Carolina (see David Anderson's 1991 paper referenced in this post) prompted me to look into Early Archaic point chronology in Florida. Sassaman directed me to this very nice (2012) paper by Michael Faught and James Waggoner.  Faught and Waggoner's discussion of multiple lines of data (radiocarbon, typological, and statigraphic sequences) relevant to evaluating the idea of Early/Middle Archaic population discontinuities in Florida could be used as a blueprint for state-by-state studies across the east.

Eight Wheels of Death: Totally Worth Seven Dollars

This post marks two firsts: my first mention of roller derby and my first movie review. The short film Eight Wheels of Death is a homegrown effort associated with the Bleeding Heartland Roller Derby in Bloomington, Indiana. I picked up a copy when I went to see my daughter skate last weekend (she's in the junior league Bloomington ThunderBirds). The movie is about what you'd expect, and that's going to be the extent of my review (here's the trailer).It was not the cinematography that made it worth $7 to me, but the fact that purchasing it supports roller derby. I was pretty impressed with the creativity, energy, and team-building that I saw both at my daughter's practice and at the actual event. I didn't see much of the adult league match (a hometown contest between the Farm Fatales and the Slaughter Scouts) because I got drafted for a shift in the concession stand, but I came away with both a lot of positive feelings and substantial curiosity about roller derby.  As best I can tell, we're now in at least the fourth or fifth generation of popularity of roller derby. There's a really interesting history as to how this activity has changed over the decades as its popularity has cyclically risen and fallen.  I'm not anywhere close to understanding it, but it's fascinating. And it's also got me pondering why and under what circumstances we sometimes (but not always) describe cultural/technological change as "generational."  It seems like identifying "generations" is kind of a real-time way of temporal typologizing (imposing nominal categories on more-or-less continuous variation). We do it for fighter aircraft and roller derby, but not for basketball and cars.

The Siege of Fort Motte and the Carolina Spring

I spent Friday working with Steve Smith (Director of SCIAA) and two volunteers on a survey at Fort Motte, site of a Revolutionary War siege and battle. There is a lot of interesting historic period archaeology here, and going out with Steve was a nice opportunity to participate and learn something new. Steve and Jim Legg are using systematic metal detecting survey, among other things, to try to pin down where on the landscape various parts of the Fort Motte story unfolded.  Yesterday we were working in the general area where some of the Patriot forces would have been camped during the siege. We found several good colonial-period artifacts (e.g., a musket ball, cast iron kettle fragments, and a brass finial probably from a flag or spontoon), I got some experience using a metal detector, and had a good time talking with the volunteers. I also saw the first dragonfly I've seen so far this year, and got to complain about the early March heat. It really is a different world down here as far as the weather.  I'm going to need to hustle if I'm going to get any of my own fieldwork going before the spring explosion of plant growth makes things like long distance total station work impossible.

I'm now on chapter 5 (out of 6) of Ken Sassaman's (2010) book The Eastern Archaic, Historicized. As I wrote a few days ago, Sassaman's book is a fascinating attempt to re-boot our understanding of the Archaic archaeology of the Eastern Woodlands. It takes a fresh look at change over the course of the eight millennia of the eastern Archaic, augmenting the familiar processual lens (with it's focus on ecology and adaptation) with one that foregrounds historically-continent phenomena such as migration, diaspora, ethnogenesis, and short-term events. It's a good read.

The Eastern Woodlands is a big area, and I don't know any archaeologist who claims mastery of all of it. As far as the Archaic, the part I'm most familiar with probably remains the central Ohio Valley and the lower Great Lakes.  I worked in southern, central, and northern Indiana for a total of nine or ten years, give or take, between the mid-1990s and 2006.   

Sassaman (2010:129) discusses the pins in the context of his ideas about Middle/Late Archaic social boundaries and ethnogenesis.  Following Jefferies' analyses, he suggests that variation in the pins is essentially telling us about the composition and external relationships of the societies that made them: 

The impetus for my 2003 MCJA paper was to ask if any the variability in the pins was related to time. The carved and engraved pins were produced, after all, over a period of at least 1000 radiocarbon years. If styles come and go through time (as they tend to do), then the mixtures of styles present at any one site may be a result of the passing of time in addition to (or instead of) various kinds of social interactions. This is an analytically important issue: it's tough to interpret variation correctly if you don't have a handle on the time component. Imagine trying to use junkyards to understand the structure of the auto industry without knowing that a '57 Chevy comes from a different era than a '95 Toyota.

Based on what I did, I think there's a good case to be made that at least some of the variation in pin characteristics is temporal. I used combinations of head type and decoration to create a seriation of the bone pins. I combined the relative sequence suggested by the seriation with radiocarbon data to produce a chronology:

My chronology, which I regard as preliminary, suggested that square-top an fishtail pins were produced relatively early in the sequence and t-top and crutch-top pins rather late.  Not having kept up with the literature (and falling out-of-touch with many of my colleagues actively doing CRM in the Ohio Valley), I do not know whether pins discovered since the MCJA paper have falsified the chronology I proposed. Occurences of t-top or crutch-top pins prior to 5500 RCYBP or square-top or fishtail pins after 5500 RCYBP would suggest that the ordering and dating of my chronology is wrong. I would be interested to know about pin finds since 2002, or any other sources of data that are relevant (I'm travelling right now and don't have access to my printed sources and the time/space to spread everything out and have a fresh look).

Carved bone pins were produced during the Middle/Late Archaic in several areas of the Eastern Woodlands, and there is significant variability both within and between these regions. This 2004 paper by Dick Jefferies ("Regional-Scale Interaction Networks and the Emergence of Cultural Complexity along the Northern Margins of the Southeast") discusses the Midwestern pins and others. Jefferies (2004:Figure 4.3) illustrates pins from the Savannah River region that appear (at least superficially) to share some design elements with pins from the Midwest.  The Stallings Island pin assemblage appears to contain pins very similar to the crutch-top or t-top styles, which is interesting given the general time range of Stallings Island (ca. 4500-3500 BP?) relative to the late positioning of the style in my preliminary chronology from the Midwest (ca. 5000 RCYBP). I'll have to take some time to get caught up and go through the available data carefully and  see if it's worth formally revisiting the issue of temporal variation in pin styles in the context of Sassaman's ideas about the Archaic.