You are currently browsing the The WING Blog blog archives for November, 2011.



Serious numbers

By Mark Crovella

When times are mysterious / Serious numbers / Will always be heard

– Paul Simon

I’ve been reading “Sustainable Energy – Without the Hot Air” It’s by David MacKay — yes, the same David MacKay that wrote the terrific book “Information Theory, Inference, and Learning Algorithms”.   I got started on the topic after reading and thinking about “Networking in the Long Emergency” (which I previously posted about).    Once you start poking around in the related literature, all signs point to MacKay’s book.

The first half of the book consists of a fascinating assessment of energy consumption and production, broken down into categories like cars, planes, heating, light, etc.   The power of the book is that it makes clear where the big problems are, and which issues are just distractions.

On the right is a graphic from the book that shows the breakdown of average energy consumption per person in Britain.ConsumptionStackMacKay

What jumps out from this chart is “Jet flights.”   Surely this “average person” is jet-setting around the world, no?   Actually, no.  This bar corresponds to exactly one intercontinental trip per year. That’s it.

Well, this must be because air travel is so inefficient, no?   Again, no.   The book does a wonderful job of explaining the physics of transport and where the energy actually goes.   To boil it down: the problem is not that it’s air travel.   The problem is simply how far you travel when you go to another continent.

Of course, this makes sense.    My commute is about 40 miles per working day.  At 250 working days per year, that’s 10,000 miles in a year.   For comparison, next month I’ll attend CoNEXT in Tokyo.   The round trip is 14.290 miles, for a five day trip.

So what does all this have to do with networking?    Nowadays, there is a growing research effort on “green networking” and “greening the Internet.” My take is that to really make a difference in favor of responsible energy use, we should be beefing up the Internet.    I take anywhere between 4 and 8 trips per year, often traveling overseas 3 or 4 times in a year.   That kind of travel absolutely dwarfs all my other energy consumption combined.    What if I could eliminate one or two of those trips through the use of telepresence?   That would actually make a significant impact on my carbon footprint.

What do we need to make the routine use of telepresence commonplace?  The social / human factors answer is that we need telepresence to provide an acceptable substitute for the personal experience of being in a room with a group of people.    And we need to carefully identify the meetings where being together with a group of people socially is an essential component, and distinguish those from meetings where the social component is an afterthought.    For example, I think that some conferences fall in the first category, and some meetings fall in the second.

The engineering answer is that we need a quantitative improvement in the Internet, and a qualitative improvement in HCI.    At present, the Internet is not quite up to multiway-telepresence as a reliable service on a global basis.   But the current rate of network buildout, if it continues, will take care of that.    The real issue is the HCI component: how we think about our displays.   For telepresence to be routine, we need to stop thinking about displays as tools that sit on our desk and allow us to manipulate computers.   We need to think about displays as part of building infrastructure — something that is designed into every office space and has standard properties that can be relied upon to make the telepresence experience consistent.    We know what to expect in terms of social and nonverbal cues when we are in a room with someone.   We need to figure out how to make that consistently available over the Internet.

So, the bottom line for me is that while “greening the Internet” is important, “Internetting people” will make a bigger difference in the long run…