Michael Hudson Talk & Green New Deal Discussion
on November 14th, 2009 at 4:42 pm
Michael Hudson was a recent and welcome visitor to Australia, and I helped arrange a talk by him at Customs House that many people on this blog supported financially, and quite a few attended. My own attempt to record the speech was unsuccessful–the sound quality was just too low–but another recording of the event (by Sean Reynolds from Politics in the Pub) was more successful than mine. Here it is below. My apologies for taking so long to post it, but I’ve been even busier than usual recently and I simply didn’t have the time to do so until now.
The sound quality is not great (I recommend using headphones rather than relying on your computer’s built-in speakers) and the image is low resolution, but it is a record of Michael’s speech for those who were unable to be there. The discussion chaired by Miriam Lyons from the Centre for Policy Development is also very much worth watching.
On a related note, I took part in a discussion at the “Green New Deal” conference in Melbourne last month with Greens Senator Christine Milne, and community activists Jake Wishart, Joan Staples and Hendro Sangkoyo, on the best means and methods of effecting real action on climate change.
The good people at SlowTV were there once again recording the discussion. Click below if you’d like to watch. This is a professional quality recording, so the sound and visual quality is extremely high–I wish we’d managed the same for Michael’s talk at Customs House. It shows the enduring value of professional media production over what us amateur media types can do, even with enhanced consumer level technology.
I’m in Helsinki now and have a ton of work to do this week before I can put up any new posts or particularly contribute to the discussion here. Once that work is finished, I’ll be posting several videos, including a detailed presentation of my multi-sectoral model of the economy made to the UNEP in Bangkok on last Tuesday.
Hi Steve,
Thanks for that. I’ve got it pretty much running but my curves aren’t much like yours yet. Maybe it’s units. When you write r=5%, you mean r=0.05 yr^(-1)? My background in this kind of thing is in kinetics, so I prefer to write k where you have 1/w. So when you write tau=1/26, I write k=26 yr^(-1)? Meaning that the corresponding variable “turns over” (roughly speaking; there’s a problem with terminology here) 26 times per year?
Again, any comments you have would be appreciated.
That’s correct djc. I would do likewise except Mathcad doesn’t yet support defining units inside ODE blocks. My economic colleagues of all persuasions have little to no experience in this area, so I’ve written a paper where I gently move from the kinetic expressions you’re using to time lags.
Thanks. No time to read your paper yet, but I think time “lags” is not a good description. When I saw that term I looked for things like F(t-tau) and when I saw it appear as F(t)/tau I thought you were using some kind of approximation for F(t-tau), which I thought would have to be a very poor one (something like a multiplier, which you are obviously trying to get away from). I was a bit slow to see it as a relaxation time, and know you probably can’t use the term, but maybe you need to invent a new one (at least so that people don’t think they know what it means). But I see your problems … interest rates are not rates but rate constants, etc.
When I have time I’ll look at your paper.
It’s the standard vernacular in systems engineering djc. They call what I am using a time lag, and expressions like (t-tau) a time delay.
Steve,
I was about to ask about the “time lag” term. Shouldn’t it be called the “time constant”?
http://en.wikipedia.org/wiki/Time_constant
http://en.wikipedia.org/wiki/RC_time_constant
I know what you mean however time lag may be confused with the latency (or delay) by someone with electronics/networking background:
http://en.wikipedia.org/wiki/Lag
In your case I think we are talking about the parameter inversely related to velocity of money
http://en.wikipedia.org/wiki/Velocity_of_money
which is the average time of the cycle of getting and spending a certain amount of money like wage.
Does it make sense or is it even more confusing?
Ak,
The world is nonlinear. Most models are based on linearity because it is more intuitive, less surprising and analytical solutions exist (i.e. for the convenience of the modeller) and it often does a good job.
My polynomial example is relatively simple to express as a differential equation, but difficult to mathematically solve without resorting to numerical approximations. At no place does my example lead precisely to exponential growth, but for finite regions it does come arbitrarily close to exponential growth (and exponential decay in other regions). We can quickly determine this behaviour because the regions near the zero crossings are closely approximated by straight lines.
This is the process by which models are constructed — work in a local region where linear approximations are good enough for the model to give sensible results, then carefully explore the nonlinear boundaries of that region.
The excitement of our world comes from the nonlinear bits, and the transitions from one operating mode to another. Do we expect harsh discontinuities like a strut snapping within a bridge truss or do we expect gentle smooth transitions such as my example? Either case is possible from a mathematical perspective, so only by close study of real-world measurements can we decide which case applies to the situation at hand.
—
Steve, with respect to nomenclature, I’ve always used the following:
* When a cleanly delimited discrete event is followed later by another discrete event, I call it a time delay.
* When an exponential curve (or approximation thereof) is in evidence I call it either an exponential time constant to be proper or just a time constant as shorthand.
* When a cyclic signal is in evidence and one feature of the cycle comes a bit later than some other feature of the cycle I call it a phase angle
* I tend to use lag and lead as just general indicators of which came first (e.g. A lags B in this situation).
That’s just the way I’ve seen these things used.
I have a copy of “Modern Control Engineering” by Ogata who uses lag to describe any elements of a system that would cause the output the lag behind the input for whatever reason, and lead has similar usage in the reverse direction. Thus, for example a lag network is another name for a low pass filter, a lag compensator is some device that deliberately adds lag to the system in order to compensate for some other system behaviour and so on.
Ogata brings up the concept of transportation lag to describe the situation where you make a change in one place but you can’t see the effect of that until something works its way through. In a finance context, if a cheque has a fixed clearing time of three days, that would be a transportation lag.
Ogata defines a specific term delay time to be the time it takes for a system to react to a step function input such that the system output gets halfway to its final resting state. This is in the context of terms such as rise time, and settling time.
The term time constant is used to describe most any time value that turns up in an equation, also Ogata fluidly switches between Bode analysis, complex pole/zero analysis and time domain so time constants often become corner frequencies or just points on the complex plane with minimal explanation.
Ogata is a reasonably well respected book in control engineering so if you borrow it from a library and scan through for the basic concepts you will at least be in the ballpark w.r.t. usage.
Steve,
Thanks. So far I’ve managed to replicate “Bank Accounts in a Growing Economy” in your Dijon05 (after finally noticing the log scale).