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Comment Re:PNAS contributed paper (Score 4, Interesting) 48

that's the way the majority of Journals operate, most don't care that the author will hand out electronic copies to anyone who asks, many will post it on their university's web site.

Actually, the publishers DO care about generating income from their copyright, and for instance require extra subscription fees from universities in order for students to be allowed to copy articles that they already have access to. I'm repeatedly warned that my University could be fined if I copy a figure from a paper into my lecture slides and then "publish" them by distributing them to my students.

Academic publishing is a two way street the academics and journals need each other because "publish or perish" applies to both sides.

Academics do need to publish but they don't need commercial publishers to do so. There's a growing movement against the traditional journals - fuelled by the extortionate fees required for electronic access to the catalogue of publishing houses such as Springer and Elsevier. Universities cannot function without access to the literature, and this is your tax dollar being funnelled into the pockets of the publishers.

sure subscriptions are expensive compared to (say) people magazine, but if you pay peanuts for a job then only monkeys are going to apply.

The people who do the hard work behind the articles - the authors, the editors, and the reviewers - are not paid by the journal. The only paid staff are administrators and copy editors, who in my experience introduce more mistakes into the text than they correct.

Comment Re:Silly me (Score 1) 459

Agreed, many trivial things can be handled by email. However, if you need to discuss or explain anything that's even slightly difficult conceptually then nothing beats an interactive conversation. It's much easier to gauge how much your peer understands (and therefore background you need to cover) when you can interact in real time.

Comment Re:autopilots acting on bad data or coding issues? (Score 1) 301

A320 crashes http://www.airdisaster.com/cgi-bin/view_details.cgi?date=03221998&reg=RP-C3222&airline=Philippine+Airlines

The aircraft overran runway 4 while landing. A malfunction of the onboard flight computers prevented power from being reduced to idle, which inhibited thrust reverse and spoilers from being used. The offending engine was shut down, and brakes applied, but the aircraft was unable to stop before the end of the runway

I couldn't read the article you referenced ("server not responding"), but the accident report states this was caused by pilot error, not malfunctioning computers. From Wikipedia: "A selection by the pilot of the wrong mode on the onboard flight computers prevented power from being reduced to idle, which inhibited thrust reverse and spoilers from being used. The offending engine was shut down, and brakes applied, but the aircraft was unable to stop before the end of the runway".

There's a surprising number of people who believe that the high level of automation on Airbus is intrinsically more dangerous, but the figures show that the Airbus A320 is the safest narrow-body jet you can fly on. It's true that automated stuff can go wrong, but this can be more than compensated for by the ways it makes flying (or driving) safer.

Comment Re:Remote working is the future (Score 1) 117

3.3kW/h is TONS to keep any reasonably insulated house scorching hot

I assume you mean 3.3 kW, but I would be interested to see a source stating that this is enough to maintain a 20 degree (Celsius) difference between inside and outside for any "reasonably insulated" house.

And for the love of god you moron you didn't say "10kW/h" you said "10 kW/h for 10 hours"

There's no need to be offensive. It was you who said "10kW/h for 10 hours". You're using kW as a measure of energy, and kW/h as a measure of power. This is incorrect, as I've pointed out. "kW/h" would be a unit at the rate at which power changes.

How dumb are you?

Smart enough to know the difference between kW, kWh and kW/h. Here's a reference which may help you understand.

Comment Re:Remote working is the future (Score 1) 117

Firstly, according to your figures above (where you say 100 kWh is equivalent to driving 180 miles), 60 miles is equivalent to 33 kWh. This corresponds to 10 hours at 3.3 kW. 3.3kW is not enough to keep a house warm in subzero temperatures unless it has no windows.

Secondly, 10 kW/h means '10 kilowatts per hour', which has no physical meaning whatever. A Watt is a unit of power, not energy.

Comment Re:Remote working is the future (Score 2) 117

Note that kW is a unit of power, kWh is a unit of energy

Your figures weaken the support for your argument (that staying at home is greener than driving to work) significantly: they suggest it's greener to drive to work as long as it's less than 90 miles away from your home.

I disagree with your calculation, but the point remains broadly the same. Here's an alternative calculation. According to Wikipedia, 1 US gallon of gasoline is equivalent to 33 kWh, so 100kWh is equivalent to 3 gallons US. At 45 mpg US you can go 135 miles, not 180.

You can look at this the other way round. Driving 60 miles at 45mpg US is equivalent to 44kWh of energy usage. For it to be worth staying at home for 10 hours, you would have be able to keep your home warm with less than 4.4 kW. That's roughly the power output of two old-fashioned electric bar heaters. Do you get freezing temperatures where you live?

It's difficult to be more precise because the figures depend on lots of things - how cold is the place you live, how efficient is your car, how you define "equivalence" between gasoline and other energy forms - but you've illustrated the following point very well: most people wrongly assume that the energy required to heat their home is negligible relative to the cost of driving anywhere.

Comment Re:Remote working is the future (Score 2) 117

How much energy does it actually take to heat your house... because it's not 10kW/h.

"Kw/h" is not a unit of either energy or power. However, I can confirm that 10kW is approximately the power needed to keep my house comfortable in the winter. I know this because I know the ratings of the radiators in the house at 60 celcius, and I also know that they need to be kept at close to 60 celcius more or less constantly.

Comment Re:Remote working is the future (Score 3, Insightful) 117

Perhaps some numbers would be helpful here.

We have a small semi-detached house with cavity wall insulation, loft insulation, and double glazing. We still need over 10kW to heat in the cold months. If we're out of the house for 10 hours, we save roughly 100 kW hours (*). How far will your car go on that amount of energy?

(*) Of course, it's not that simple because we have to use extra heat to bring the house back to normal temperature when we get home. A more accurate analysis would compare the temperature-time graphs for the two scenarios and use Newton's law of cooling. Nevertheless, the above figures are roughly correct.

Comment Re:Remote working is the future (Score 4, Insightful) 117

Get used to it people. It's a green initiative.

No necessarily. If you don't work at home, you also don't have to keep your home warm (or cool) enough to be comfortable during the day. The office, on the other hand, will be kept at a reasonable temperature whether you're there or not.

My wife's work is about 30 miles away, but she works from home most days. We calculated that, on the coldest winter days, the carbon cost of driving to work was about the same as the extra heating that would be needed if she stayed at home. If you have a shorter commute, or have a greener method of transport than driving a car, it's quite likely that it's greener to work in the office than to work at home.

Comment Re:Well, they couldn't prove... (Score 3, Insightful) 285

they eat corn alright, as does most of the world, in the form of processed food. You find corn derivatives in a bewildering varieties of industrial foods.

You imply that the French, and indeed the rest of the world, eat significant amount of processed food. It's difficult to get hard data on this, but my impression (from having lived there) is that processed food is a much smaller part of their diet than in the US. This article says that Americans eat rather more processed food than other countries, but it's difficult to compare because "baked goods" and "ready-to-eat" in the US and in France are rather different.

On the other hand, "most of the world" is certainly not eating significant amounts of industrial food - in China and India it's almost unheard of.

Comment Re:This is why I prefer Boeing. (Score 2) 603

On Airbus vehicles, if the avionics computers crash, the airplane crashes. There's exactly ZERO way to pilot the computer manually in such a failure.

Completely untrue. When the avionics 'crash', the flight system progresses through 'alternate' to 'direct' law where the pilot has direct control of the plane.

Moreover, the avionics system can and does overrule pilot input. So if you get sensor malfunctions like this, even if the pilot is trying desperately to save the plane, the computer can still crash you.

Have a look at the statistics (pages maintained by a pro-Boeing pilot, by the way) and you'll see (i) for all your hysterical fear of Airbus aircraft, the fly-by-wire Airbus aircraft (i.e. all except A300 and A310) are just as safe as their Boeing counterparts (ii) there are no examples of an Airbus crash caused by the computer overriding the will of the pilot.

Comment Re:Nothing to do with chaos theory (Score 1) 676

I see your point, but if x1 and (x1+x2)/2 make very different predictions then you don't expect them both to be equally good at describing a data set generated by x1 - unless (i) your data are less informative than your prior, or (ii) unless your predictions are in a regime where the parameters are identifiable but the training data are in a regime where they are not. I admit that this might often be the case when trying to modelling real systems...

Comment Re:Nothing to do with chaos theory (Score 1) 676

Sure, the posterior mean or maximum might be very different from the true parameter value, but the the true value should sit somewhere in the full posterior distribution. If parameters have non-identifiability issues then the posterior should be very flat, but if you base your predictions on the posterior then this will show up in the distribution of your predictions. I would have thought this would only lead to a bias if your prior were TOO informative, wouldn't it?

Comment Nothing to do with chaos theory (Score 1) 676

The phenomenon this guy has observed is nothing to do with chaos theory, as several posters think, but rather to do with error propagation and model uncertainty. This is an issue whether the model is chaotic or not. His mistake is to think that calibration has to choose a single set of parameters, and then one has to make a single prediction from the model. Statistical methods can take into account many sources of uncertainty, including the range of parameters that could have produced the original data and intrinsic stochasticity in the model. The best way to do this is using Bayesian techniques.

You're still limited by how realistic your model is, and this is likely to be the real problem with economic models. However, Carter's argument (that it's fundamentally impossible to fit a model to itself and then make consistent predictions) is wrong.

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