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Comment: Re:Is this at least user-selectable? (Score 1) 470

by Alioth (#47728881) Attached to: Google's Driverless Cars Capable of Exceeding Speed Limit

I just did some back of the envelope calculating on this. In a typical car with decent performance, you can accelerate at about 4 meters/sec sq (about 0-60 in a little under 7 sec). Working in meters because it's a lot easier: imagine this, an intersection with good visibility. At 40 mph approach speed, the earliest you can tell that the other driver is going to blow through the intersection (at right angles to you) will be 2 seconds. Before that he's still got time to stop. But let's say you're suspicious of the other driver so at 2 seconds out you are instantly ready to take action (and not taking action will result in the front corner of your car making the initial collision with the front corner of his car). Your cars are Ford Focus length, 4.5 meters long. You are both doing 40 mph (18 meters/sec).

So where are you at time = 2 if you decide to accelerate? The reference point is the leading edge of your car. The distance you travel will be determined by in this case the function d(t)=18t + 2t^2. At 2 seconds no part of your car must be between 36 meters and 37.8 meters from the position where you decided to hit the gas (so the leading edge of your car must not be at the position 36m to the position 37.8m + length of your car, which is 4.5m, so 42.3m). If you hit the gas the leading edge of your car would be at 44m, so you only just miss and you need to have a high performance car to do that (Focus ST or Focus RS). If you're in a more normal car, or an older car that's a little bit worn out, and have a 0-60 time of 9 seconds (3 m/s squared), the formula would be 18t + 1.5t^2, and the leading edge of your car will be at 42m, in other words the other vehicle will clip the rear of your vehicle and you will now have the additional speed to some how get rid of during the ensuing crash.

What about braking? A typical car will decelerate at 8.2m/s^2 if you slam on the brakes. ( http://www.michigan.gov/docume... ) So the distance formula for braking will be 18t - 4.1t^2. If you were to slam on the brakes, at the critical time the leading edge of your car would be 19.6m from your starting point - you'd miss the collision by a very comfortable 16.4 meters. Even if it were lashing with rain, and your braking performance were halved, you would miss the collision by almost 10 meters.

The conclusion here is that the margins are much much tighter (in the best case, you only get away with it by just over a meter) if you try to accelerate than if you try to brake (where you miss the collision in the worst case by better than 9m). Acceleration in reality would probably be worse than calculated if you're in an automatic transmission car because you won't really start accelerating much until the transmission sorts itself out. In a manual you'll only be better off if at the decision point you're already in the ideal gear for accelerating. Acceleration may be a valid path to take if you are in a Bugatti Veryron or a Lamborghini Countach or on a motorcycle, but even so the margins are going to be much more comfortable if you mash the brakes instead (given a super car has very good brakes, and a performance motorbike has sticky tires and very good brakes). And if the collision does occur, if you've braked there's a great deal less energy in the system so the outcome is likely to be much less severe.

Comment: Re:Is this at least user-selectable? (Score 1) 470

by Alioth (#47728023) Attached to: Google's Driverless Cars Capable of Exceeding Speed Limit

Accelerating through the intersection won't work at all if you're already going 40 (most normal cars don't accelerate that well at that speed, certainly in the US where automatics are the norm you'll have to wait for the transmission to kick down). If you have enough warning of an impending impact that acceleration would make any difference at all, likely maximum braking would prevent the impact altogether.

Comment: Re:Windows 8 (Score 1) 668

by Alioth (#47728001) Attached to: Linus Torvalds: 'I Still Want the Desktop'

I run gnome 3 on a dual monitor setup. It is a development machine, mostly used for Java, C and scripting, but also documentation, web browsing, email (i.e. usual office tasks), system administration of servers etc. I don't have any complaints about it. The only customization I really care about is focus follows mouse, and Gnome 3 supports that without any difficulty.

What's wrong with alt-tab to switch applications? It's what I use and works awesomely well under gnome 3.

Comment: Re:Farce (Score 1) 239

by Alioth (#47727977) Attached to: Would Scottish Independence Mean the End of UK's Nuclear Arsenal?

20 minutes faster journey up north is infinitely more useful to me and millions of others than nuclear annihilation. The HS2 infrastructure is something (well, barring the aforementioned nuclear annihilation) that will be around in a century's time. Trident won't be useful at all and won't have that long of a service life.

Comment: Farce (Score 1) 239

by Alioth (#47727527) Attached to: Would Scottish Independence Mean the End of UK's Nuclear Arsenal?

The whole UK nuclear deterrent is a colossal waste of money anyway. It would be far better to get rid of them (who do they deter? who would we use them against? And in the case of a global thermonuclear war it wouldn't even make a difference anyway) and spend the money on conventional forces that we can actually use and probably are more of a deterrent to potential enemies.

Comment: Re:Stopping staring at your navals (Score 1) 668

by Alioth (#47727199) Attached to: Linus Torvalds: 'I Still Want the Desktop'

The same thing is true of WIndows if you have to install it from scratch, and it doesn't come pre-installed. It can take several hours to get a fully functional Windows build including much searching for drivers unless you have hardware that is completely supported by what MS ships on the installation CD.

If you're complaining about "grep" (which is not an invention of Linux, it's a standard unix tool that has existed since the 70s), try to guess what the "cacls" command is supposed to do in Windows without looking it up.

Comment: Re:Windows 8 (Score 1) 668

by Alioth (#47727177) Attached to: Linus Torvalds: 'I Still Want the Desktop'

I don't know what all the hate of Gnome 3 is other than basic resistance to change. When Debian 7 came out, it had upgraded to gnome 3. Of course being a Debian user I don't get the early and possibly unstable versions - but it took me all of 15 minutes to figure out gnome 3 and I never looked back. It seems perfectly easy to use and does what I want it to do and it doesn't get in my way. This is on my main work system, and I do all tasks on it, use it 8 hours a day, it's not a machine for limited uses. Never felt the desire to go back to Gnome 2 or anything that looks like it.

Comment: Re:The power of the future... (Score 1) 298

by Alioth (#47710795) Attached to: If Fusion Is the Answer, We Need To Do It Quickly

No. Fusion power is roughly $80bn of research away. The problem is the funding has been so meagre that we will never actually reach the goal at current rates of funding. If $80bn sounds a lot, it's not - it's only 0.11 Iraq Wars. We saw fit to spend around $750bn (at a highly conservative estimate - that's the US DOD's own estimate) on bombing Iraq, but we don't see fit to spend just more than 1/10th of that amount on freeing ourselves from dependence on that entire region forever.

Comment: Re:Is this at least user-selectable? (Score 1) 470

by Alioth (#47710685) Attached to: Google's Driverless Cars Capable of Exceeding Speed Limit

Probably not. Most normal cars don't accelerate that quickly but have extremely effective brakes. If you're driving properly and at least taking a quick glance at crossing traffic when approaching a traffic light, you'll probably see the red light jumper before he's jumped the light. At that point you can slow down *far more rapidly* than you can speed up.

About the only vehicles where acceleration may change the outcome are supercars and motorcycles.

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