Hugh, > > (Phil henshaw) "What kind of information might indicate the approach of > common resource limits? How would that be different from evidence that > other > users are breaking their agreements? As independent users of natural > resources tend to have less information about, or interest in, each > other's > particular needs than, say, cyclists in a peloton, how would they begin > to > renegotiate their common habits when circumstances require it?" [ph] Great, you apparently see the general problem. The form of the information you're looking for needs to be rediscovered in every situation. It's flying blind. If you're not looking for the uncharacteristic indications of how you're interacting with other independent actors in your environment you'll miss a whole lot more than if you do look for it.
The most frequent long range forecaster of the approach of common resource limits is diminishing returns, since resource exploitation is done by taking easy things first. It invariably begins by discovering more and bigger easy things and ends in discovering fewer and smaller ones later. If there are multiple users of a resource they'll skillfully avoid conflict with each other until they're abruptly forced into conflict when the options to avoid it dwindle to zero in the circumstance (say two species needing to turn to their less favorite food and colliding). That end game is first observable as an eruption of complexity in the dodges needed by each user to stay out of another user's way, and then by things like cheating on the conventions for staying out of each others way that developed doing that... The growth curves of diminishing returns and complexity in the environment are strong signals telegraphing the state of relationships among the whole community of otherwise 'unseen' and 'unrecognized' users that seek to avoid conflict with each other. In terms of a peloton my first thought is much like yours. I'd guess that most competitors who plan on breaking with the pack will wait for a good time to do that. At that time in the race they'll closely watch each other's hesitations and glances to read the advantageous time to break the temporary 'agreement' to share the load... As a racer I'd be looking at all the things on your list, sort of integrated as a total measure of the 'alacrity' of my peloton mates in mounting each rise. It's at the point where the 'spring in their step' starts to fall off that I'd look for a chance to make my move, timed so the competitor I'm worried about is in a disadvantageous position, something like that. In that case the 'resource depletion signal' is the switch from homeostatic stability in the pace to the phase of positive feedback in the group's weakening stride, the first appearance of huffing and puffing you might say. That's the indication of phase 4 in the basic 5 phase developmental sequence in any process from its beginning to end, 1¸¸.2·´¯¯3¯¯4¯`·5.¸¸ The information about when the peloton is no longer brightly responding to a increase in grade is available to every rider about equally, but not perceived the same way by each. Each one will also have different ways of conceiving their separate strategies for when the safety of the group breaks. In the environmental case of growing needs for both food and fuel and farmers competing for aerable land forced to decide whose food gets squeezed out by whose fuels, the comeraterie of the end game may be missing of course... Phil > > Here is a short essay that looks at Phil's questions of resource > consumption > from the perspective of a peloton analog. It doesn't seek to answer > the > questions, but rather proposes a model in which to analyze them. It > may be > rather simplistic against the backdrop of sophisticated economic > theory, but > as a very real system, I suggest the dynamics of pelotons may provide > insight into them. The scope of my essay may also be overly broad, and > in > that respect, incomplete, but my hope is that there are a few kernels > that > may assist Phil's analysis, or are at the very least, interesting. > > Information exchange, resource consumption and sharing in bicycle > pelotons: > a model for analyzing competitive systems > > Hugh Trenchard > > Bicycle racing is by definition competitive, and involves strategies > for the > cooperative distribution and exploitation of individual and collective > resources. Individual resources exist in the form of energy available > for > consumption within a rider's body, either in the form of glucose stored > in > rider's livers and muscles, or body fats, and the physiological > mechanisms > which allow riders to expend that energy. Rate of individual resource > consumption may be reduced by drafting, which occurs when riders are > positioned in zones of lower air pressure, either directly behind > others > riders', or at angles to the wind direction. Riders in drafting > positions > reduce energy expenditure by as much as 30 - 40% over a rider in front > at > 40km/hr, depending on positioning within the peloton (Hagberg and > McCole, > 1990). > > Reduction of energy expenditure in drafting positions is also a > collective, > or shared resource. It is a collective resource when riders in > competitive > situations either cooperate or exploit this resource to maximally > reduce > their own individual resource expenditure or the expenditure of allies. > Allies may be team-mates, but are also frequently competitors from > different > teams who cooperate when a peloton has split into groups, thereby > temporarily becoming allies to achieve specific objectives, before > again > becoming competitors. The relative and continuous balance between > cooperation and exploitation occurs most notably when a peloton has > split > into groups of two or more, and the objective of group(s) ahead is to > remain > ahead of following groups, while the reverse objective exists for > groups > behind, which is to reintegrate groups ahead. In situations like these, > free-riders, quite literally, are prevalent, repleat with a number of > modes > of punishment. A more detailed account of that, however, is beyond the > scope > of this discussion. > > In the course of their resource consumption, the information cyclists > receive or generate is largely visual. There is also vocal information, > and, > at the highest levels there is nearly always communication exchanged > between > riders within the peloton and sources outside the peloton (coaches or > "director sportifs"), via radio contact - an advancement in racing > tactics > that has developed and been allowed in races for roughly 20 years now. > Generally riders have limited global information due to obstructed > viewing > (i.e. blocked by riders surrounding them) and primarily receive only > local > information about the riders immediately surrounding them. One reason > (albeit a secondary reason) for advancing or falling back within a > peloton > is to gather information about the positions of competitors. Some of > this > information may be relayed verbally through information links within > the > peloton (other cyclists), or riders acquire the information by visual > observation, or through radio contact. > > The information riders seek is primarily threefold: > > 1 competitor positioning > > 2 apparent rider resource consumption > > 3 course constraints > > > > 1. Competitor positioning > > This is determined by > > > a. local observation of riders in immediate 360 degree visual field, > where > course topography is flat > > b. partial or complete global observations of peloton where elevation > and > course configuration allow visual information to be obtained from > higher or > lateral vantage points (e.g. if a cyclist is near the rear of a > descending > peloton on an open road, the rider has a clear view of cyclists' > positions > ahead); > > c. positional information may also be gleaned by implication, namely > if a > cyclist is at the front, he or she knows all her competitors are > behind, and > will see them if they try to pass. Similarly, but more anxiety causing, > if a > cyclist is at the back, he will know all competitors are ahead of him. > > 2. Resource consumption > > Information about resource consumption is evidenced by competitors' > apparent > discomfort, such as facial contortions, body positions, or by other > indicators such as failures to take pulls at the front (during > cooperative > situations), struggling to hold minimal distances between wheels, > deteriorating pedalling form, poor gear ratio selection, or > observations > about fluid intake or food consumption during the race. For example, if > a > rider has lost his water bottle at a critical point, others will have > exploitative information about his sugar levels. > > 3. Course constraints > > This refers to the physical course and its changes: is there a hill > approaching, is there an obstacle approaching, is there a bend in the > course; how strong is the wind, and from what direction is it coming? > In > road racing, courses may be out-and-back or point-to-point, and change > continuously and, aside from general course information obtained before > commencing the race, course predictability is relatively low; in road > circuit races, which may consist of several loops of a course of, say, > 1 km > to 15km or more, the course repeats regularly and so there is a greater > degree of course predictability, in addition to information obtained > before > hand; a track course is oval, is either 250m or 333m long and is > banked, and > thus is highly regular and allows the greatest degree of predictability > and > available global information. > > All of these factors provide clues as to when individual and shared > resource > limits are approaching. These limits arise primarily in the following > situations: > > > 1. Shared resources are lost, such as during sufficiently steep hill > climbs, when speeds fall to a point when drafting advantage is > negligible > (<16km/h (Swain, 1990)) and differentials between cyclists'respective > power > output capacities overwhelm the equalizing effects of any drafting > advantage; > > 2. Shared resources are not-negotiated, such as during a final sprint > for > the finish line, or other situations when speeds are beyond a certain > threshold between sets of rider causing peloton disintegration** > > 3. Shared resources are too dangerous, such as on high-speed descents, > where collisions with others, obstacles or proceding on trajectories > outside > physical course parameters (e.g. plummetting over a cliff on the > outside of > a hairpin turn!) are avoided by maintaining distances outside of > drafting > range). > > Applying the peloton model > > A peloton may thus be viewed as a basic resource sharing system which > may > provide clues as to how resources are shared and consumed in other > systems, > especially competitive ones - which arguably most such systems > involving > resource consumption are. I suggest that, in principle, when we > investigate > the question of how to re-negotiate resource sharing, we can first seek > to > understand the nature of these categories of information: competitor > positioning, apparent resource consumption, and course constraints. > These > factors by themselves are nothing new, but applying a peloton model to > other > systems, at least in any rigourous fashion, is new. > > When information about these factors is not available globally, as is > most > often the case, we can examine features exhibited by other systems of > resource sharing that may be analogous to what occurs in pelotons. For > example, energy in a peloton is reduced, essentially, by following the > paths > of other riders. Any natural system in which path following serves to > reduce > energy expenditure is analogous to a peloton. As a simple example, when > a > forager tramples a path through snow to a food source, that forager > expends > more energy than all that follow in the established pathway. Forager > dynamics may be examined against the model of peloton dynamics and its > pattern thresholds. > > In pelotons, thresholds exist where observable collective emergent > behaviours are exhibited, described by the following phases: > > Phase 1 Transitional > > As cyclists set off at the beginning of a race, there is a period > during > which the speeds are sufficiently low for cyclists to have no > physiological > necessity to draft one another, as they are all well below individual > pain > thresholds or maximal power output capacity. The phase is characterized > by > roughly random internal peloton movements, or low-pattern formation > within > the peloton. > > Phase II Rotational > > As speeds increase, a transition occurs whereby resource sharing > becomes > necessary as cyclists approach (but remain below) pain and maximal > output > thresholds, and when the collective drafting resource is exploited. In > this > phase, a balancing occurs between energy expenditure and optimal > position > within the peloton. Because it is a competitive situation, it is better > to > be positioned as close to the front as possible. As this is a > continuous > imperative, rotational movements occur within the peloton, when riders > move > up and down the peloton, or are caught in "eddies" whereby they advance > for > relatively short distances within the peloton, before being shifted > backward > again, and then attempt to move forward again. These movements occur > while > riders attempt to use as little energy as possible to advance. So, > where > there are riders who shift to the outside of the pack (facing the wind > by > doing so), other riders will follow in their draft. > The result is a rotational pattern whereby riders advance up the sides > for > relatively long stretches, while riders drop back within the peloton, > and > while within > the peloton there are smaller-scale rotations, or eddies. The > rotational > patterns which emerge are analogous to the roiling effects of boiling > liquid, as riders "heat up" by greater energy expenditure in moving > forward, > and cool down by reduced energy expenditure in moving backward through > the > peloton. Incidentally, this pattern is also similar to rotational > patterns > observed in emperor penguin huddles (Ancel, et al., 1997; Stead, 2003). > > > Phase III Stretching > > A third phase transition occurs when the pace shifts up beyond another > threshold, whereby the speeds are too high for there to be continuous > rotational movement within the peloton, and the peloton stretches into > a > single line. This phase, while easily observable, is a precurser to a > final > transition where the peloton begins to splinter: individual riders fall > off > the back, or separations occur in the line of riders which following > riders > cannot bridge, resulting in regions of peloton instability and loss of > cohesion. > > > Phase IV Disintegration > > In this last phase riders fall outside of drafting range, and > cooperation > (or coupling between cyclists) disintegrates as cyclists become either > in > direct competition with the each other. This phase is analogous to the > phase > change between liquid and gas, as cyclists move outside of drafting > range, > thereby de-coupling. In bicycle racing this phase is usually temporary, > however, as speeds drop quickly, and, through a series of > agglomerations, > the entire peloton either reintegrates or sub-groups form which > cooperate > internally but which are also in direct conflict with each other. In > the > case of sub-groups in conflict, it is the objective of chasing groups > to > reintegrate groups ahead, while it is the objective of groups ahead to > stay > ahead of chasing groups. > > Conclusion > > Although a peloton is a resource sharing system consisting of human > agents > with competitive human objectives, it is also an energetically dynamic > system that exhibits self-organized thresholds and emergent patterns. > It is > reasonable to speculate that when we look at other natural systems in > which > resources are shared and exploited, there are analogous patterns which > emerge at certain energy consumption thresholds. The physical > manifestations > of such thresholds and emergent patterns may not be easy to identify, > but > here we have a microcosmic model of a competitive, self-organizing > system > which may provide some clues. > > ____________________________ > > References > > > Hagberg, J., McCole, S. The Effect of Drafting and Aerodynamic > Equipment on > Energy Expenditure During Cycling, 1990, Cycling Science, 2, p. 20 > > Swain, D. Cycling Uphill and Downhill. Sportscience 2(4), > sportsci.org/jour/9804/dps.html, 1998 (2682 words) > > **which threshold I have previously argued on the basis of a coupling > model, > having called it the peloton convergence ratio (PCR). PCR =(Wa-Wb/Wa)/D > where Wa is the maximum power output (watts) of cyclist A at any given > moment; Wb is the maximum power output of cyclist B at that moment > (assuming > Wa>Wb), and D is the percent energy savings due to drafting at the > velocity > travelled: Trenchard, H., Mayer-Kress, G. Self-Organized Oscillator > Coupling > and Synchronization in Bicycle Pelotons During Mass-start bicycle > racing. > Book of Abstracts, International Conference on Control and > Synchronization > of Dynamical Systems, Oct 4-7, 2005, Leon, Gto, Mexico. Ratios of =<1 > and > cyclists remain coupled; >1 and cyclists de-couple, when points of > instability in pelotons occur and peloton disintegration begins. > > Ancel, A., Visser, H., Handrick, Y., Masman, D., Le Maho, Y. Energy > Saving > in huddling penguins. Nature, Vol. 385. 23 Jan 1997; Stead, G. An > Artificial > Life Simulation to Investigate the Huddling Behaviour of Emperor > Penguins. > Submitted in partial fulfillment for the degree of MSc in software > systems > technology. > > ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
