with the fact that it will not be near people AKA a few miles away and you have pretty harmless and nothing to fear
Yup that's good if there is no significant wind. Launch requirements may make that essentially guaranteed; I don't recall how much wind is tolerated before a launch is cancelled but it seemed like a fair bit - and if it doesn't explode after launching and some reasonable altitude has been gained.
OK loooong time ago so I may be misremembering but it seems to me there were arguments about this with one or more of the Apollo missions because a tiny reactor was going to be taken along and the statistical analysis was provided for detonation at altitude and the resulting expected increase in number of cancer deaths. The reactor might not have been uranium based - like I said looooong time ago.
, we wonder why our world is so fucked up when artists (some actually talented people) are forced to put up with shit like that.
Nope, it isn't fucked up because artists are treated like that - it is fucked up because we are all treated like that in various and sundry ways. IMHO that's a very important distinction. I do agree with you about the "innocent until..." though.
How do you figure it's free to make and distribute?
By make I think he means manufacture the physical copy - not produce the issue which has to be done for both digital and hard copy editions - but the digital edition is free to manufacture because there is in fact no manufacture. The only way it wouldn't be free is if the layout etc. was different for the digital edition otherwise the digital can use the same publishing files as the physical. However also eliminating the physical edition does put the whole produciton cost up to the stage of being able to print onto the digital edition so in that case, yes, it is not free to produce the digital edition.
Similarly compare the cost of digital distribution to sticking a mailing label on, maybe a plastic bag, cost of postage, personnel to actually get the stuff down to the loading dock and into the mail system. Ok for the digital edition there may be some increased load on servers etc. but compared to physical distribution it is so much cheaper it is virtually free and that remains true even if you terminate the physical edition altogether.
Would it be cheaper to stop us later when we have advanced so far as to have fast cheap interstellar travel, or now?
It would be so easy... come to the more advanced countries, manipulate things to cause a real-estate boom, say by planting some idea abut a ridiculous investment vehicle in some banker's/financier's head, and then watch things crumble back to the dark ages...
Well if the point is to avoid famine then it seems like the very first thing to do would be to see what it would cost to stockpile enough non-perishable food to prevent famine for 1 year... gasoline is stockpiled to prevent catastrophic shortages so why not food?
Of course the food would have to be cycled in/out to prevent the stockpiles spoiling but that shouldn't be hard and lots of food has amazingly long shelf lives. Then, assuming that over time the stockpile was cheaper than the subsidies, you could eliminate those costly subsidies...
The things I mentioned don't restrict conclusions to the domain of commuting. Since you have made speed an issue, and as I have already pointed out, the same justification you gave also justifies driving a car... people just don't have the time to waste.
As for your continued attempt to charge the cost of resting to the cost of going from A to B - I'm sorry but it is ludicrous and afaics only has one purpose - to try and make cycling look better than it actually is. Hopefully everyone else can see that if energy is expended for activity A then you can't charge it to activity B especially when A is going to happen regardless of whether or not B happens. I find the insistence on trying to do this is usually a characteristic of people with a "religion" about something - in this case bicycling.
As for your your claim that you can walk infinitely slowly, it is simply wrong. One might be able to move at a rate that approaches infinitely slow but you won't be walking. Walking is a very specific mode of pedestrian movement. It requires that you fall - you swing one limb out in front and then fall onto it - this is what defines walking, as opposed to say shuffling. You move your leg and torso forward until gravity causes you to continue to move forward. At this point you cannot stop this - you also can not make it slower until the forward leg finally contacts the ground again, and you most certainly cannot make it infinitely slow. This is how walking is defined. If you are not engaging in this cyclic pattern of falling and catching yourself then you may be shuffling, sliding, or any number of other things but you are not walking.
Finally to use a source you have supplied elsewhere ( http://www.engineeringtoolbox.com/met-metabolic-rate-d_733.html ) if you are walking at 2 Km/hr your total rate of energy expenditure is 675 BTU/hr and if you are cycling it is 1780 BTU/hr. They don't give the speed of cycling but they do put it in the same category as golf. This of course is before adjusting for the base rate - if you were simply standing not doing anything you would be using 430 BTU/hr so the actual net cost of walking over standing still is 245 BTU/hr and for cycling it is 1350 BTU/hr.
Finally, and as I've also pointed out before, the figures are for what is basically an optimum case for cycling. We should also see the figures for travelling over sand, up a hill, over rocky terrain, on ice, into a headwind, etc. etc.
45 day suspension for beating a man until his face breaks and he suffers permanent damage to his sight????? WTF is wrong with the world when this guy not only isn't in jail but gets to go back to his job??? Then he has the nerve to sue the person catching him on tape? He should get a year in jail just for having the audacity to try that since it is a form of harassment and intimidation.
ok, I was just quoting from someone else and not from the original article (dangerous I know) so I didn't see the figures you are supplying. Based on the numbers you are giving then yes 8 would be the break even point - assuming the passenger body weight doesn't affect the fuel consumption of the bus which is probably true enough unless it goes from 8 to say 32 passengers.
So for every bus with 2 people you need another with 14... probably not hard in an urban centre but outside the core I can see that being hard to achieve.
And of course if we we a fuel efficient compact instead of a sedan then you probably need an average of more like 12 to break even. If the people in the compact cars car pool with just one other person then the break even point is 24... that's starting to get pretty high. I'm not trying to be argumentative just for the sake of it... it just seems some people, not necessarily you, think that buses are always "good" and I don't think it is that clear cut.
One of the problems with all this is that it tends to be an all or nothing choice. While there are car sharing companies, like Zip Cars, that just charge you for when you use the vehicle they are not very convenient or popular so far. So people are left with choosing between a car or bus - because you have bought the car and paid for the insurance it makes no sense to take the bus because the car payments and insurance are fixed costs whether you use the car or not... the gas and maintenance isn't enough to discourage using it once you have accounted for the bigger costs. Then of course there are the times when you want to bring things from a store or go on a trip etc.
If we had a system where, say, your insurance costs were based on the number of miles driven then people might be a lot more likely to use transit for a lot of their travel even if they owned a car. I lived for several years in Toronto which had a very good transit system and a very poor parking situation so I generally would not drive in Toronto unless I had a good reason - I'd still want a car though for the times I need to run an errand, pick things up or leave the city.
The way I read it was that on a per passenger basis the carbon footprint of the off-peak bus was twice that of a sedan and driver. So if the off peak buses average N/2 passengers then their carbon footprint is equal to twice N/2 sedans and drivers which is equal to the carbon footprint of N sedans and drivers. So the off peak bus passengers have a carbon footprint twice that of someone driving a sedan.
This doesn't really surprise me as in my experience buses in the downtown core are at capacity in rush hour but in between they are maybe 50%-75% full and before and after rush hour less than that and late in the evening only a handful of passengers except for the hour when the bars let out. But then you have to add in the the non-downtown core buses which are badly under-utilized any time other than rush hour. So the average number of passengers for off peak buses is probably very low and those buses are very big. The ones around here are up to (estimating here) 60' long articulated vehicles. Even the older non-articulated buses are a good 40' long. So it's not hard to believe they have a carbon footprint many times that of a sedan and if you go to compacts that are getting 40-50mpg the comparison is probably a lot worse. It would be interesting to see the actual numbers so there was less guessing though.
So running those things is making a big carbon footprint and only having a few passengers is very inefficient. But if you don't run them throughout the day and evening, and frequently, then people won't use them because it is too inconvenient. This is the real downfall of buses. The only way I can see around this, while still maintaining a frequent enough service to keep ridership, would be to have a duplicate fleet of smaller buses/vans to be used at other than peak hours.
You say that running a bus is twice as bad as driving a sedan, so if a bus has two passengers, then that would be equal to two people each driving a sedan.
Go back and read the post I was quoting - it seems pretty clear to me that the statement means running an off peak bus is twice as bad as a car - on a per person basis, not on a per vehicle basis. So:
hen that would be equal to two people each driving a sedan
is wrong. It would be equivalent to two people each driving two sedans - or the off peak bus carrying an average of N passengers is as bad as 2N sedans being driven.
What you need to do is determine what the (weighted) average number of passengers is on an off peak bus. We don't have those numbers handy but we do know that off peak means not full because the buses are generally full at peak times. So if a bus has a maximum capacity of N passengers then off peak buses carry somewhere between 0 and N-1 passengers. Without further information all we can do is guess that an off peak bus generally carries N/2 passengers which means every off peak bus that is run is equivalent to driving N sedans the same distance.
Now given the above do the math - how many peak, i.e., 100% full, buses have to be running so that in combination with the off-peak buses the total carbon footprint is less than just having each passenger drive a sedan? What do you get as an answer?
Your assumptions I think assume no time constraints.
You don't need to think about it at all - if you read what I wrote you will find that I specifically stated that - and I explained why. I suggest you go back and re-read what I actually said.
Your definition for "most efficient travel" allows me to walk infinitely slowly
It most certainly does not. Again I suggest you go back and understand what I wrote.
I don't have those three hours.
When did this become restricted to commuting? I certainly made no such restriction... you appear to have done so in order to try and find some way to prove cycling is better than walking. This is what I mean about eliminating the religious element. But great. I don't have those two hours you spend cycling to work - not when I can get do it by car in 40 minutes. At an hourly rate of $150 I would be losing $200 each work day, or about $4,000/month, by bicycling instead of driving. So driving is obviously the optimal mode of transport for commuting.
As for the rest you seem to keep dredging up these bizarre segues and hand waving, such as undefined requirements for exercise, in your attempt to deify cycling... Get as serious as determining the most efficient level of walking, and of cycling, and then you will have something meaningful to compare and discuss. Until you can deal with those most basic facts everything else you say is really just you waving your arms around and being a cheerleader.
The absolute minimum energy expenditure for walking is set by your resting metabolic rate, which is what I used. We burn about 75 kCal/hour. That means that if you are walking at 3mph, IF YOUR INCREMENTAL ENERGY EXPENDITURE WAS ZERO, you would still burn 25 kCal/mile. A cyclist, at 4mph, accounting for both resting and cycling energy, consumes only 22.5 kCal/mile. Cycling wins, even against a hypothetical zero-effort 3mph walk. The problem with walking is that it is just too slow, and you don't get to amortize your base rate across enough miles. Walk slower, the base rate cost only goes up.
Sorry but I find that an extremely biased view of what is happening. Your base rate consumption is happening every minute of the day no matter what you are doing. To say that you get there faster so you don't count any of the base rate consumption after you get there and the pedestrian is still walking would be a complete distortion as would "averaging" them into the activity cost.
You live, you consume calories. The base rate calories aren't consumed because the the person is cycling, or because the person is walking, they are consumed because the person exists, independent of any other activity. The only thing that matters is how much energy is expended to get from A to B. Note that is "to get from A to B" not "while getting from A to B". The calories that would be expended whether you are travelling or not are irrelevant. If they would be expended even if you are not travelling then you cannot reasonably charge them against travelling just because that is what you happen to be doing at some point in time.
According to what you have written the cyclist travelling at 4mph burns 90 kCal in an hour. IIRC you also say the same cyclist not moving would burn 75 kCal. So the cost of travelling by bike is 15 kCal. IIRC you haven't stated the conditions so we'll assume that is on the level on a paved road with no wind accelerating or retarding the cyclist.Now the question is how much does the walker consume, as a result of travelling, i.e. the additional energy expenditure, to go that same 4 miles at the most efficient rate? Maybe I missed it but I don't think that that has ever been stated.
Then it would clearly be of interest to make the same comparisons for different terrain, windage and other conditions and see how the two compare. You'd also want to be sure the pedestrian has shoes that are designed for walking and the best energy recovery practical - being able to spend least up to the cost of a good bike.
As for sweat and showers - I think it is possible that you may have a biased view as to whether you need a shower, the people beside you are usually the best judge of whether you need a shower:)
A cyclist can travel the same speed at a lower energy expenditure (4mph, I included that one). Therefore, less sweat.
1. As I said speed is not really relevant. Perhaps the pedestrian goes 1/2 mile an hour and doesn't sweat at all.
2. But of course the major comparison I made is to a car - the drive won't be sweating at all no matter how fast.
the wind from pedalling forward has a decent cooling effect, so if you can taper your speed down
Oh boy so he'll be covered in dried sweat by the time he stops. Yummm:)
Anyway the point still remains - what is the most energy efficient way to get from A to B? It's still not clear that it isn't walking. Certainly nothing presented so far tells us what the minimum expenditure for walking would be, so the question hasn't been answered.
The GP claimed that, and although it may well be true, nothing he put in his post actually proved that general claim.
And just to be ever so slightly whimsical if you were going to compare driving to work and cycling to work you would have to compare the energy cost of the cyclist showering before getting close to his/her workmates. Possibly the same in comparing a cyclist to a pedestrian who also wouldn't need to shower if strolling along at a relatively sedate pace - even uphill.
Yes but most of what you seem to be comparing is walking at one speed to cycling at a different speed - that isn't really a proper comparison for obvious reasons. Additionally at 4mph you aren't walking - more likely a slow run, jogging or at the very least a really stiff walk. This is not an efficient speed for walking just as driving 100mph is not an efficient speed for driving.
Speed, as in "can I get there quickly?". is not a relevant issue, e.g. it doesn't matter that you can get somewhere faster by cycling than walking - because you can get somewhere faster by car than by cycling. The interesting measure - at least to start - would be something like this: using the most energy efficient speed for the mode of travel how many calories does it take to travel a mile? What if the mile is uphill? What if the terrain is sand? etc. etc.
Yes but the comment in the summary was about energy for walking, not driving, and as if there was no energy required for cycling. Unless the figures are given for both walking and cycling then the comment is not only meaningless but misleading as it implies walking it seriously inefficient compared to cycling.
assuming... you ride the bike 2,000 miles per year
What do you do for the other 10,000 miles a year most people travel? And let's apply some logic to the facts in the summary (dangerous, I know)...
an ordinary sedan's carbon footprint is more than 10 times greater than a conventional bicycle's
and
off-peak buses account for more than 20 times as many greenhouse gases as a bicycle
In other words running off peak buses is twice as bad as having people drive sedans. Which is more or less what I've been thinking every time a see a honking huge bus go by with 2 or 3 passengers on it. How many full load trips does it take to make up for one trip where the bus is more or less empty?
What about the carbon footprint of walking? 'Walking is not zero emission because we need food energy to move ourselves from place to place
And bicycling doesn't take any food energy?
What I notice in my city, which has spent many millions of dollars creating bicycle lanes, is that there aren't that many bicycles using them to begin with and when it rains, which it does with great frequency, the usage drops by a factor of about 10. On one bridge I regularly went over, with fairly steep up and down slopes, the pedestrians outnumbered the cyclists about 4 to 1 and that was on sunny days, on rainy days it was much higher. I'm not anti-bicycle, I use one myself, but I wish the religious aspect of it would go away so an actual fact based assessment about bike lanes, pedestrain walkways and car lanes could occur.
Most programmers shouldn't be worrying about optimization. What they should be worrying about is not putting bugs in their code. When they get to the point where they routinely write robust clear code that doesn't do stupid things like assuming a buffer is going to be big enough for whatever string is being written to it, then they can start worrying about optimizations.
I find it really instructive to read the descriptions that come with, for example, Ubuntu automatic updates to fix security (and other) holes... it tells you a lot about the kind of errors programmers are still making.
Such things are expensive, and in the long run it's cheaper to be fast and sloppy than slow and lean.
I bet you meant to say something else because it never pays to be sloppy in designing, coding or testing software. Never.
As far as the Knuth quote he is talking about intermediate and low level optimization - optimizations at the language level - I am sure he did not intend his net to catch optimizations like choosing the appropriate algorithm to solve the general problem at hand.
As far as intermediate and low level optimizations this is one of the benefits of experience - you learn to recognize situations where putting some extra work into a particular piece of code will have a pay-off, by whatever metric is relevant, big enough to justify the effort.
it is impossible to differentiate the evil guilty who got away with a good deal from the people who thought they would be declared innocent and chose to fight.
Don't forget the innocent people who take a plea bargain because they can't afford to put up a proper fight, or if they can afford it realize it is still a risk and decide they cannot afford the consequences of being found guilty compared to the less dire consequences of a plea bargain.
It's probably just a question of convenience for the searcher so getting it removed makes it a little harder to be found. IANAL but it seems to me that if there is *any* connection between the people putting up the pictures and the people charging money to get them taken down then there is a charge of blackmail to be made. No?
Sigh... should have proofread one more time (maybe I'm making my own point about lazy programmers - yeah, yeah, that's the ticket)... In the parent "the nul byte isn't " should have read "things like the nul byte and null pointer aren't".... mea culpa
With all due respect to Hoare (and he deserves lots of it) the nul byte isn't the problem. The problem is almost always people who don't know how to program (or do and are too lazy) and thereby create problems - entirely preventable problems.
We still see software updates being made to fix bugs originating in, for example, buffers getting overwritten by strings too long for the buffer, because the programmer is too lazy to spend 2 minutes putting in a check. Instead of that one person putting in 2 extra minutes millions of people get to spend 1 minute installing the fix and the debuggers spend god knows how much time trying to track down the source of the problem in the first place.
To anticipate some of the usual objections:
"it will make the code inefficient" - let's talk about the 99.9% of the cases where that doesn't matter "I don't have time for that" - yeah, you do, you aren't that important buddy
etc.
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Yup that's good if there is no significant wind. Launch requirements may make that essentially guaranteed; I don't recall how much wind is tolerated before a launch is cancelled but it seemed like a fair bit - and if it doesn't explode after launching and some reasonable altitude has been gained.
OK loooong time ago so I may be misremembering but it seems to me there were arguments about this with one or more of the Apollo missions because a tiny reactor was going to be taken along and the statistical analysis was provided for detonation at altitude and the resulting expected increase in number of cancer deaths. The reactor might not have been uranium based - like I said looooong time ago.
Nope, it isn't fucked up because artists are treated like that - it is fucked up because we are all treated like that in various and sundry ways. IMHO that's a very important distinction. I do agree with you about the "innocent until..." though.
It's more likely the he was tipping his hat to "The Tacit Dimension" by Polanyi - a very dense book to read. See:
http://en.wikipedia.org/wiki/Michael_Polanyi
By make I think he means manufacture the physical copy - not produce the issue which has to be done for both digital and hard copy editions - but the digital edition is free to manufacture because there is in fact no manufacture. The only way it wouldn't be free is if the layout etc. was different for the digital edition otherwise the digital can use the same publishing files as the physical. However also eliminating the physical edition does put the whole produciton cost up to the stage of being able to print onto the digital edition so in that case, yes, it is not free to produce the digital edition.
Similarly compare the cost of digital distribution to sticking a mailing label on, maybe a plastic bag, cost of postage, personnel to actually get the stuff down to the loading dock and into the mail system. Ok for the digital edition there may be some increased load on servers etc. but compared to physical distribution it is so much cheaper it is virtually free and that remains true even if you terminate the physical edition altogether.
Would it be cheaper to stop us later when we have advanced so far as to have fast cheap interstellar travel, or now?
It would be so easy... come to the more advanced countries, manipulate things to cause a real-estate boom, say by planting some idea abut a ridiculous investment vehicle in some banker's/financier's head, and then watch things crumble back to the dark ages...
Well if the point is to avoid famine then it seems like the very first thing to do would be to see what it would cost to stockpile enough non-perishable food to prevent famine for 1 year... gasoline is stockpiled to prevent catastrophic shortages so why not food?
Of course the food would have to be cycled in/out to prevent the stockpiles spoiling but that shouldn't be hard and lots of food has amazingly long shelf lives. Then, assuming that over time the stockpile was cheaper than the subsidies, you could eliminate those costly subsidies...
Ummm and just why would we expect American science to be especially colour blind?
This would seem to imply that, e.g., Britain, Canada etc. are more racist countries than the US.
The things I mentioned don't restrict conclusions to the domain of commuting. Since you have made speed an issue, and as I have already pointed out, the same justification you gave also justifies driving a car... people just don't have the time to waste.
As for your continued attempt to charge the cost of resting to the cost of going from A to B - I'm sorry but it is ludicrous and afaics only has one purpose - to try and make cycling look better than it actually is. Hopefully everyone else can see that if energy is expended for activity A then you can't charge it to activity B especially when A is going to happen regardless of whether or not B happens. I find the insistence on trying to do this is usually a characteristic of people with a "religion" about something - in this case bicycling.
As for your your claim that you can walk infinitely slowly, it is simply wrong. One might be able to move at a rate that approaches infinitely slow but you won't be walking. Walking is a very specific mode of pedestrian movement. It requires that you fall - you swing one limb out in front and then fall onto it - this is what defines walking, as opposed to say shuffling. You move your leg and torso forward until gravity causes you to continue to move forward. At this point you cannot stop this - you also can not make it slower until the forward leg finally contacts the ground again, and you most certainly cannot make it infinitely slow. This is how walking is defined. If you are not engaging in this cyclic pattern of falling and catching yourself then you may be shuffling, sliding, or any number of other things but you are not walking.
Finally to use a source you have supplied elsewhere ( http://www.engineeringtoolbox.com/met-metabolic-rate-d_733.html ) if you are walking at 2 Km/hr your total rate of energy expenditure is 675 BTU/hr and if you are cycling it is 1780 BTU/hr. They don't give the speed of cycling but they do put it in the same category as golf. This of course is before adjusting for the base rate - if you were simply standing not doing anything you would be using 430 BTU/hr so the actual net cost of walking over standing still is 245 BTU/hr and for cycling it is 1350 BTU/hr.
Finally, and as I've also pointed out before, the figures are for what is basically an optimum case for cycling. We should also see the figures for travelling over sand, up a hill, over rocky terrain, on ice, into a headwind, etc. etc.
45 day suspension for beating a man until his face breaks and he suffers permanent damage to his sight????? WTF is wrong with the world when this guy not only isn't in jail but gets to go back to his job??? Then he has the nerve to sue the person catching him on tape? He should get a year in jail just for having the audacity to try that since it is a form of harassment and intimidation.
ok, I was just quoting from someone else and not from the original article (dangerous I know) so I didn't see the figures you are supplying. Based on the numbers you are giving then yes 8 would be the break even point - assuming the passenger body weight doesn't affect the fuel consumption of the bus which is probably true enough unless it goes from 8 to say 32 passengers.
So for every bus with 2 people you need another with 14... probably not hard in an urban centre but outside the core I can see that being hard to achieve.
And of course if we we a fuel efficient compact instead of a sedan then you probably need an average of more like 12 to break even. If the people in the compact cars car pool with just one other person then the break even point is 24... that's starting to get pretty high. I'm not trying to be argumentative just for the sake of it... it just seems some people, not necessarily you, think that buses are always "good" and I don't think it is that clear cut.
One of the problems with all this is that it tends to be an all or nothing choice. While there are car sharing companies, like Zip Cars, that just charge you for when you use the vehicle they are not very convenient or popular so far. So people are left with choosing between a car or bus - because you have bought the car and paid for the insurance it makes no sense to take the bus because the car payments and insurance are fixed costs whether you use the car or not... the gas and maintenance isn't enough to discourage using it once you have accounted for the bigger costs. Then of course there are the times when you want to bring things from a store or go on a trip etc.
If we had a system where, say, your insurance costs were based on the number of miles driven then people might be a lot more likely to use transit for a lot of their travel even if they owned a car. I lived for several years in Toronto which had a very good transit system and a very poor parking situation so I generally would not drive in Toronto unless I had a good reason - I'd still want a car though for the times I need to run an errand, pick things up or leave the city.
The way I read it was that on a per passenger basis the carbon footprint of the off-peak bus was twice that of a sedan and driver. So if the off peak buses average N/2 passengers then their carbon footprint is equal to twice N/2 sedans and drivers which is equal to the carbon footprint of N sedans and drivers. So the off peak bus passengers have a carbon footprint twice that of someone driving a sedan.
This doesn't really surprise me as in my experience buses in the downtown core are at capacity in rush hour but in between they are maybe 50%-75% full and before and after rush hour less than that and late in the evening only a handful of passengers except for the hour when the bars let out. But then you have to add in the the non-downtown core buses which are badly under-utilized any time other than rush hour. So the average number of passengers for off peak buses is probably very low and those buses are very big. The ones around here are up to (estimating here) 60' long articulated vehicles. Even the older non-articulated buses are a good 40' long. So it's not hard to believe they have a carbon footprint many times that of a sedan and if you go to compacts that are getting 40-50mpg the comparison is probably a lot worse. It would be interesting to see the actual numbers so there was less guessing though.
So running those things is making a big carbon footprint and only having a few passengers is very inefficient. But if you don't run them throughout the day and evening, and frequently, then people won't use them because it is too inconvenient. This is the real downfall of buses. The only way I can see around this, while still maintaining a frequent enough service to keep ridership, would be to have a duplicate fleet of smaller buses/vans to be used at other than peak hours.
Go back and read the post I was quoting - it seems pretty clear to me that the statement means running an off peak bus is twice as bad as a car - on a per person basis, not on a per vehicle basis. So:
is wrong. It would be equivalent to two people each driving two sedans - or the off peak bus carrying an average of N passengers is as bad as 2N sedans being driven.
What you need to do is determine what the (weighted) average number of passengers is on an off peak bus. We don't have those numbers handy but we do know that off peak means not full because the buses are generally full at peak times. So if a bus has a maximum capacity of N passengers then off peak buses carry somewhere between 0 and N-1 passengers. Without further information all we can do is guess that an off peak bus generally carries N/2 passengers which means every off peak bus that is run is equivalent to driving N sedans the same distance.
Now given the above do the math - how many peak, i.e., 100% full, buses have to be running so that in combination with the off-peak buses the total carbon footprint is less than just having each passenger drive a sedan? What do you get as an answer?
You don't need to think about it at all - if you read what I wrote you will find that I specifically stated that - and I explained why. I suggest you go back and re-read what I actually said.
It most certainly does not. Again I suggest you go back and understand what I wrote.
When did this become restricted to commuting? I certainly made no such restriction... you appear to have done so in order to try and find some way to prove cycling is better than walking. This is what I mean about eliminating the religious element. But great. I don't have those two hours you spend cycling to work - not when I can get do it by car in 40 minutes. At an hourly rate of $150 I would be losing $200 each work day, or about $4,000/month, by bicycling instead of driving. So driving is obviously the optimal mode of transport for commuting.
As for the rest you seem to keep dredging up these bizarre segues and hand waving, such as undefined requirements for exercise, in your attempt to deify cycling... Get as serious as determining the most efficient level of walking, and of cycling, and then you will have something meaningful to compare and discuss. Until you can deal with those most basic facts everything else you say is really just you waving your arms around and being a cheerleader.
Sorry but I find that an extremely biased view of what is happening. Your base rate consumption is happening every minute of the day no matter what you are doing. To say that you get there faster so you don't count any of the base rate consumption after you get there and the pedestrian is still walking would be a complete distortion as would "averaging" them into the activity cost.
You live, you consume calories. The base rate calories aren't consumed because the the person is cycling, or because the person is walking, they are consumed because the person exists, independent of any other activity. The only thing that matters is how much energy is expended to get from A to B. Note that is "to get from A to B" not "while getting from A to B". The calories that would be expended whether you are travelling or not are irrelevant. If they would be expended even if you are not travelling then you cannot reasonably charge them against travelling just because that is what you happen to be doing at some point in time.
According to what you have written the cyclist travelling at 4mph burns 90 kCal in an hour. IIRC you also say the same cyclist not moving would burn 75 kCal. So the cost of travelling by bike is 15 kCal. IIRC you haven't stated the conditions so we'll assume that is on the level on a paved road with no wind accelerating or retarding the cyclist.Now the question is how much does the walker consume, as a result of travelling, i.e. the additional energy expenditure, to go that same 4 miles at the most efficient rate? Maybe I missed it but I don't think that that has ever been stated.
Then it would clearly be of interest to make the same comparisons for different terrain, windage and other conditions and see how the two compare. You'd also want to be sure the pedestrian has shoes that are designed for walking and the best energy recovery practical - being able to spend least up to the cost of a good bike.
As for sweat and showers - I think it is possible that you may have a biased view as to whether you need a shower, the people beside you are usually the best judge of whether you need a shower :)
1. As I said speed is not really relevant. Perhaps the pedestrian goes 1/2 mile an hour and doesn't sweat at all.
2. But of course the major comparison I made is to a car - the drive won't be sweating at all no matter how fast.
the wind from pedalling forward has a decent cooling effect, so if you can taper your speed down
Oh boy so he'll be covered in dried sweat by the time he stops. Yummm :)
Anyway the point still remains - what is the most energy efficient way to get from A to B? It's still not clear that it isn't walking. Certainly nothing presented so far tells us what the minimum expenditure for walking would be, so the question hasn't been answered.
The GP claimed that, and although it may well be true, nothing he put in his post actually proved that general claim.
And just to be ever so slightly whimsical if you were going to compare driving to work and cycling to work you would have to compare the energy cost of the cyclist showering before getting close to his/her workmates. Possibly the same in comparing a cyclist to a pedestrian who also wouldn't need to shower if strolling along at a relatively sedate pace - even uphill.
Yes but most of what you seem to be comparing is walking at one speed to cycling at a different speed - that isn't really a proper comparison for obvious reasons. Additionally at 4mph you aren't walking - more likely a slow run, jogging or at the very least a really stiff walk. This is not an efficient speed for walking just as driving 100mph is not an efficient speed for driving.
Speed, as in "can I get there quickly?". is not a relevant issue, e.g. it doesn't matter that you can get somewhere faster by cycling than walking - because you can get somewhere faster by car than by cycling. The interesting measure - at least to start - would be something like this: using the most energy efficient speed for the mode of travel how many calories does it take to travel a mile? What if the mile is uphill? What if the terrain is sand? etc. etc.
Yes but the comment in the summary was about energy for walking, not driving, and as if there was no energy required for cycling. Unless the figures are given for both walking and cycling then the comment is not only meaningless but misleading as it implies walking it seriously inefficient compared to cycling.
What do you do for the other 10,000 miles a year most people travel? And let's apply some logic to the facts in the summary (dangerous, I know)...
and
In other words running off peak buses is twice as bad as having people drive sedans. Which is more or less what I've been thinking every time a see a honking huge bus go by with 2 or 3 passengers on it. How many full load trips does it take to make up for one trip where the bus is more or less empty?
And bicycling doesn't take any food energy?
What I notice in my city, which has spent many millions of dollars creating bicycle lanes, is that there aren't that many bicycles using them to begin with and when it rains, which it does with great frequency, the usage drops by a factor of about 10. On one bridge I regularly went over, with fairly steep up and down slopes, the pedestrians outnumbered the cyclists about 4 to 1 and that was on sunny days, on rainy days it was much higher. I'm not anti-bicycle, I use one myself, but I wish the religious aspect of it would go away so an actual fact based assessment about bike lanes, pedestrain walkways and car lanes could occur.
Most programmers shouldn't be worrying about optimization. What they should be worrying about is not putting bugs in their code. When they get to the point where they routinely write robust clear code that doesn't do stupid things like assuming a buffer is going to be big enough for whatever string is being written to it, then they can start worrying about optimizations.
I find it really instructive to read the descriptions that come with, for example, Ubuntu automatic updates to fix security (and other) holes... it tells you a lot about the kind of errors programmers are still making.
I bet you meant to say something else because it never pays to be sloppy in designing, coding or testing software. Never.
As far as the Knuth quote he is talking about intermediate and low level optimization - optimizations at the language level - I am sure he did not intend his net to catch optimizations like choosing the appropriate algorithm to solve the general problem at hand.
As far as intermediate and low level optimizations this is one of the benefits of experience - you learn to recognize situations where putting some extra work into a particular piece of code will have a pay-off, by whatever metric is relevant, big enough to justify the effort.
Don't forget the innocent people who take a plea bargain because they can't afford to put up a proper fight, or if they can afford it realize it is still a risk and decide they cannot afford the consequences of being found guilty compared to the less dire consequences of a plea bargain.
It's probably just a question of convenience for the searcher so getting it removed makes it a little harder to be found. IANAL but it seems to me that if there is *any* connection between the people putting up the pictures and the people charging money to get them taken down then there is a charge of blackmail to be made. No?
Sigh... should have proofread one more time (maybe I'm making my own point about lazy programmers - yeah, yeah, that's the ticket)... In the parent "the nul byte isn't " should have read "things like the nul byte and null pointer aren't".... mea culpa
With all due respect to Hoare (and he deserves lots of it) the nul byte isn't the problem. The problem is almost always people who don't know how to program (or do and are too lazy) and thereby create problems - entirely preventable problems.
We still see software updates being made to fix bugs originating in, for example, buffers getting overwritten by strings too long for the buffer, because the programmer is too lazy to spend 2 minutes putting in a check. Instead of that one person putting in 2 extra minutes millions of people get to spend 1 minute installing the fix and the debuggers spend god knows how much time trying to track down the source of the problem in the first place.
To anticipate some of the usual objections:
"it will make the code inefficient" - let's talk about the 99.9% of the cases where that doesn't matter
"I don't have time for that" - yeah, you do, you aren't that important buddy
etc.