I have been a bit suspicious on how carbon neutrality is calculated. Especially since it is so seemingly easy for well paid actors like Leonardo Decaprio and Orlando Bloom to reach this elevated state of existance.
Shouldn't the nature of their source of livihood be taken in account? i.e. everyone who drives to the flicks, a small percentage of the carbon from their cars should go against the accounts of the people involved in the film? Things like film stock chemicals etc as well? Afterall environmentalist actors would not by so wealthy had it not been for the indirect commerce they generate with millions and millions of people. So maybe this does need to be factored in since they can opt out of their current careers and undo all the indirect environmental effects that their careers create.
Maybe outside of successful advocacy and politics nothing someone like Bloom or Gore does, on the balance on it all, really aids making the planet a better place to live; environmentally speaking.
In the case of carbon calculations for cars etc, I wonder whether things like metalurgy and energy costs in manfacturing the car in the first place, manfacture of tires and refining of engine oil are omitted.
Whilst it is true that wages need to be normalised against buying power, your argument overall is false. In most developing countries an unskilled wage barely enough to put food on the table. People literally live day to day and to skip work for a few days create a very significant financial strain. For example, taxi drivers were I live work 24 hour shifts, straight, 4+ days a week and they barely scrape together enough money to feed their families. One driver told me that if he gets sick for a few days it instantly causes hardship for him and his family. People work to the absolute limit of human endurance and simply cannot command enough wealth to buy themselves the occasional reprieve from such a grinding existance. The difference between being a working adult in the west vs being a working adult in a developing country is shocking, especially if you are unskilled. Sweatshops, where they are permitted to exist, are part of that equation.
Totally Agree. I am currently living in a country where the banks are not strictly regulated. There are over 70 banks operating here some of them are practically mum and dad affairs. Even one of the telcos is permitted to act as a bank - you can store money with them and shift it around using SMS. Whenever I need to move money into the country the heart-rate quickens. Burned nearly over a grand in dodgy 'fees' and outright errors with little avenue for recourse over the past 12 months.
I think that comparing software review to proofreading is a highly abused and inappropraite analogy.
Unlike writing prose, setting down human thought onto paper, writing code has simple, measurable and testable outcomes and objectives that the writer should be able to evaluate with ease. Consequently reviewing and testing your own work does have alot of value. Sure, getting someone else to look at your code usually has even more value because they are likely to find things you are blind to at the time. Self review is still a valid tool in a suite of possible QA practicies that like all tools has its place which you pick and choose from based on the balance of risks+costs+consequences. Self review usually comes down to how much pride you take in ensuring your code actually hits the intended target as opposed to throwing something that barely compiles over the fence for QA to deal with.
N = n-1 = number of prisoners less 1. (Don't count the leader)
k = number of signals king can mess with
logic:
Total number of signals that can be received by leader including kings false signals where all but one non leader prisoner is allowed out. i.e. the king does his best to trick the reader into thinking that all prisoners have been let out but they haven't:
LHS = (N-1)*(2k+1)+k
Total number of signals that can be received by leader where all non leaders signal less max number of signals a king can muffle. i.e. the king does his best to make the leader wait forever in indecision:
This looks like it is on the right track. Looking at the ways a king can mess with the signal:
1. trick the leader into thinking that someone signalled to them but turning cup back up and calling the leader out. To fix this may need to wait for at least n+k affirmations. This by itself falls down though because the king may choose not to signal.
2. trick a non leader into thinking they have successfully signalled but the king invalidated their signal. To fix this each non leader can signal k+1 times.
Bringing this together. Since everyone is going to signal upto k+1 times the leader should wait for n*(k+1) cups. Assuming the king doesn't mess with signals
Now if the king hides signals from the leader - leader may received k signals less. So they should wait for just n*(k+1)-k. This is less than signals from all but one user (n-1)*(k+1). Algebra works out that if n>1 this holds. If n=1 then there is just one prisoner and they say 'yes' on being called out first.
Now if the king hides tries to block all signals from one non leader - leader may receive k signals less again. Same logic as above
So i think the solution is all non leaders signal upto K+1 times, and the leader waits for n*(k+1)-k signals.
THe 3DES crypto used on these cards is safe from brute force attack because you have to brute force the card itself - and since a authentication cycle takes anywhere from 20ms to complete so you are looking at several thousand years of processing to discover a single key.
The biggest issue issue with them is that they generally a single globally a shared secret that is built into cards and readers. So potentially alot of people need to know what the secret is for purposes of card and reader provisioning/manufacture. Also apparantly it is possible to attack the silicon directly - both cards and readers. Once the secret is discovered the whole system is compromised and there is nothing you can do. It is a very brittle security system.
ISO14443 can be strengthened via various tricks such as making sure data on the card is signed using PKI - EMV relies on this heavily. To my knowledge PKI on the cards themselves is not practical - PKI is too computationally intensive for passive cards.
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I have been a bit suspicious on how carbon neutrality is calculated. Especially since it is so seemingly easy for well paid actors like Leonardo Decaprio and Orlando Bloom to reach this elevated state of existance. Shouldn't the nature of their source of livihood be taken in account? i.e. everyone who drives to the flicks, a small percentage of the carbon from their cars should go against the accounts of the people involved in the film? Things like film stock chemicals etc as well? Afterall environmentalist actors would not by so wealthy had it not been for the indirect commerce they generate with millions and millions of people. So maybe this does need to be factored in since they can opt out of their current careers and undo all the indirect environmental effects that their careers create. Maybe outside of successful advocacy and politics nothing someone like Bloom or Gore does, on the balance on it all, really aids making the planet a better place to live; environmentally speaking. In the case of carbon calculations for cars etc, I wonder whether things like metalurgy and energy costs in manfacturing the car in the first place, manfacture of tires and refining of engine oil are omitted.
Whilst it is true that wages need to be normalised against buying power, your argument overall is false. In most developing countries an unskilled wage barely enough to put food on the table. People literally live day to day and to skip work for a few days create a very significant financial strain. For example, taxi drivers were I live work 24 hour shifts, straight, 4+ days a week and they barely scrape together enough money to feed their families. One driver told me that if he gets sick for a few days it instantly causes hardship for him and his family. People work to the absolute limit of human endurance and simply cannot command enough wealth to buy themselves the occasional reprieve from such a grinding existance. The difference between being a working adult in the west vs being a working adult in a developing country is shocking, especially if you are unskilled. Sweatshops, where they are permitted to exist, are part of that equation.
Totally Agree. I am currently living in a country where the banks are not strictly regulated. There are over 70 banks operating here some of them are practically mum and dad affairs. Even one of the telcos is permitted to act as a bank - you can store money with them and shift it around using SMS. Whenever I need to move money into the country the heart-rate quickens. Burned nearly over a grand in dodgy 'fees' and outright errors with little avenue for recourse over the past 12 months.
I think that comparing software review to proofreading is a highly abused and inappropraite analogy.
Unlike writing prose, setting down human thought onto paper, writing code has simple, measurable and testable outcomes and objectives that the writer should be able to evaluate with ease. Consequently reviewing and testing your own work does have alot of value. Sure, getting someone else to look at your code usually has even more value because they are likely to find things you are blind to at the time. Self review is still a valid tool in a suite of possible QA practicies that like all tools has its place which you pick and choose from based on the balance of risks+costs+consequences. Self review usually comes down to how much pride you take in ensuring your code actually hits the intended target as opposed to throwing something that barely compiles over the fence for QA to deal with.
Wrong try again
Answer
Each non leader must signal 2k+1 times
Leader must wait for N*(2k+1)-k signals
WhereN = n-1 = number of prisoners less 1. (Don't count the leader)
k = number of signals king can mess with
logic:
Total number of signals that can be received by leader including kings false signals where all but one non leader prisoner is allowed out. i.e. the king does his best to trick the reader into thinking that all prisoners have been let out but they haven't:
LHS = (N-1)*(2k+1)+k
Total number of signals that can be received by leader where all non leaders signal less max number of signals a king can muffle. i.e. the king does his best to make the leader wait forever in indecision:
RHS = N*(2k+1)-k
Invariant that needs to hold is:
LHS < RHS
This looks like it is on the right track. Looking at the ways a king can mess with the signal:
1. trick the leader into thinking that someone signalled to them but turning cup back up and calling the leader out. To fix this may need to wait for at least n+k affirmations. This by itself falls down though because the king may choose not to signal.
2. trick a non leader into thinking they have successfully signalled but the king invalidated their signal. To fix this each non leader can signal k+1 times.
Bringing this together. Since everyone is going to signal upto k+1 times the leader should wait for n*(k+1) cups. Assuming the king doesn't mess with signals
Now if the king hides signals from the leader - leader may received k signals less. So they should wait for just n*(k+1)-k. This is less than signals from all but one user (n-1)*(k+1). Algebra works out that if n>1 this holds. If n=1 then there is just one prisoner and they say 'yes' on being called out first.
Now if the king hides tries to block all signals from one non leader - leader may receive k signals less again. Same logic as above
So i think the solution is all non leaders signal upto K+1 times, and the leader waits for n*(k+1)-k signals.
THe 3DES crypto used on these cards is safe from brute force attack because you have to brute force the card itself - and since a authentication cycle takes anywhere from 20ms to complete so you are looking at several thousand years of processing to discover a single key. The biggest issue issue with them is that they generally a single globally a shared secret that is built into cards and readers. So potentially alot of people need to know what the secret is for purposes of card and reader provisioning/manufacture. Also apparantly it is possible to attack the silicon directly - both cards and readers. Once the secret is discovered the whole system is compromised and there is nothing you can do. It is a very brittle security system. ISO14443 can be strengthened via various tricks such as making sure data on the card is signed using PKI - EMV relies on this heavily. To my knowledge PKI on the cards themselves is not practical - PKI is too computationally intensive for passive cards.