Having just walked out of my first exam this semester, I decided to write my semi-annual exam bash/rant. The exam I just had is on microeconomics, which involves quite a bit of maths. For me, who also take courses in engineering, the maths are quite easy. In fact it is so easy I question the need to waste time on them in an exam.
Take a simple example, solving a pair of simultaneous equations. We all know how to do it since year 9 or 10 and it is (usually) simple. However that doesn't mean it can be done very quickly, especially in a time critical situation such as an exam. This particular exam should be testing my knowledge on economic theory and how to apply mathematical tools (e.g., solving simultaneous equations) to get the information we sought. If I apply the correct theories I should get to a point where I can say, "OK, we have two unknowns and two equations, so we can solve for them." The test should end here because it had verified I understand the economic theories and know how to get at the answers.
But the test doesn't end there because I need to write down the actual numbers for full mark. Can anyone tell me why I need to justify to the examiner I can solve a pair of simultaneous equations in this context? To me this is just a pointless exercise that has nothing to do with economics.
I would, however, like to point out that things would be different if the question does not ask for a number, but rather an expression of the quantity we are after. Then it would be useful and interesting to fully solve for the expression because from that expression we can tell how the value will change in relation to the known parameters.
It is unfortunate that all too often exams contain numerical rather than analytical questions. Coupled with odd parameters (a=0.423 instead of a=2), you wouldn't know you made a mistake since your answer, whether right or not, is just a number. On the other hand, a mistake can be spotted more easily in an expression if you know how the variables should interact with each other.
If I want to solve mathematical problems numerically, I won't be studying economics.
Friday 15 June 2007
Saturday 9 June 2007
Intolerant Culture
The inspiration for this post started when I was considering why video games are not responsible for violent acts in real life. Clearly it is impossible to prove that video games will not make anyone more violent. Even I don't believe in that assertion. However it is my belief that video games are not the major influence of someone committing acts of violence, rather it is something more subtle that we have so far ignored.
The first thing that came to mind is the current so-called war on terror. War, whether the legitimacy of its cause, is an act of violence. Worse, it is an act of violence in real life, as opposed to what one would see in a movie or a video game. If games really induces people to become more violent, then the same should happen with seeing footages of the Iraqi conflict. If anything the latter also legitimises and actively promotes the use of force, since the war is endorsed by the U.S. Government. It is odd that people will believe simulated violence can cause violent behaviour but real violence has no effect.
As I thought harder, it occurred to me that violence is often driven by the need to retaliate. To get even. To get justice. The sue-happy culture of the United States (and probably spreading to other Western countries) is sending one message to the people: if anyone, including your closest ones, does anything that makes you worse off, sue them! Thus everyday we see on Judge Judy mothers suing their sons or ex-best friends suing each other, for mere hundreds of dollars or less. It seems to me people are getting less and less tolerant of others which explains why the smallest conflicts result in full-blown retaliatory law suits. The problem is, some people (most, hopefully) get their revenge via law suits but others prefers to use force. I believe that if people can learn to be more tolerant of others they will not desire to seek revenge, thus eliminating the source of violent acts altogether. Alas, such a scenario probably belongs to Utopia more than the real world, as it is hard to convince most people that life really isn't fair and they should just live with it.
In conclusion, video games and movie probably contributes to violence, but they are not the root of the problem. We need to look deeper into this matter and find out what provokes one to want to cause harm to another person. Only then are we able to cure the problem once and for all.
The first thing that came to mind is the current so-called war on terror. War, whether the legitimacy of its cause, is an act of violence. Worse, it is an act of violence in real life, as opposed to what one would see in a movie or a video game. If games really induces people to become more violent, then the same should happen with seeing footages of the Iraqi conflict. If anything the latter also legitimises and actively promotes the use of force, since the war is endorsed by the U.S. Government. It is odd that people will believe simulated violence can cause violent behaviour but real violence has no effect.
As I thought harder, it occurred to me that violence is often driven by the need to retaliate. To get even. To get justice. The sue-happy culture of the United States (and probably spreading to other Western countries) is sending one message to the people: if anyone, including your closest ones, does anything that makes you worse off, sue them! Thus everyday we see on Judge Judy mothers suing their sons or ex-best friends suing each other, for mere hundreds of dollars or less. It seems to me people are getting less and less tolerant of others which explains why the smallest conflicts result in full-blown retaliatory law suits. The problem is, some people (most, hopefully) get their revenge via law suits but others prefers to use force. I believe that if people can learn to be more tolerant of others they will not desire to seek revenge, thus eliminating the source of violent acts altogether. Alas, such a scenario probably belongs to Utopia more than the real world, as it is hard to convince most people that life really isn't fair and they should just live with it.
In conclusion, video games and movie probably contributes to violence, but they are not the root of the problem. We need to look deeper into this matter and find out what provokes one to want to cause harm to another person. Only then are we able to cure the problem once and for all.
Wednesday 6 June 2007
Security is a Tradeoff
Everyone is talking about security these days. Politicians want to protect their countries from terrorist attacks, while companies are worried about frauds of all kinds. These concerns led them to introduce various security measures such as more stringent checks in airports, identifying a person by their biometrics, and looking at the buying patterns of a credit card. Although there is no doubt each additional measure increases security, they also put extra burden on the process and that can add up to a large cost.
For example, it is very convenient to shop with a credit card. Just swipe the card and sign the bill and you're done. However, if your credit card details is leaked to a malicious third party, he or she can easily purchase goods from online stores under your credit. Hence this is not a very secure payment system.
Now let's consider the opposite end of the scale. Suppose every time you want to pay with your credit card the store needs to verify your identity by checking two official documents that identifies you (say your HKID card or drivers licence), as well as performing three separate biometric scans. Clearly it is now a lot harder for someone pretending to be you using your credit card, but at this point I suspect you wouldn't want to use your credit card either due to all the hassles.
The above is of course an exaggeration of what might actually happen in practice, but it illustrates an important principle, that although security measures reduces the risk of losses, it imposes its own costs. Thus it is not wise to blindly put in place any and all security measures you can think of into a system, because the cost of performing these extra steps becomes higher than what you lose by being less secure. The art of security, therefore, is to find the point where cost is minimised rather than engineering the most secure (and likely most tedious) system.
This is not to say one cannot improve security without causing extra trouble to the customers. For example, one of the biggest reason people don't (in the companies' view) adequately secure their PINs and passwords is because they want to share them with several others whom they can trust. We all do that at some point in time, and sometimes it makes sense to do that. Usually a more secure system means it's harder for people other than the account owner to gain access. But this contradicts with our needs to sometimes let people we trust to access our accounts!
In theory, if the system knows the owner gives (or would have given) another person consent to access than it should be safe to allow access for that person, but this is almost impossible to implement without increasing risk. If I want to access my mum's back account, should the bank let me? Let's say my mum give me permission today and I got in, but I try to get in again the next day. Does the bank let me in now? Can it safely assume the situation will not change in just one day? No! It needs permission from my mum again. But if my mum is always around to give permission she can just access the bank account herself!
If the bank has perfect information it will just let me in, but it doesn't. The best it can do is look at my track record and assume that I'm benign because I always have a good relationship with my mum. Again this is a tradeoff -- set the criteria too loose and anyone can access the account, too strict and we're back to where we started -- and the trick is to find the point that minimises hassles and risk of fraud. Realistically I can't imagine anyone building this kind of system just because it's so complicated and so hard to find that "middle point". That's unfortunate, because it means legitimate people like me have to "hack" into my mum's accounts just to change a credit card number.
For example, it is very convenient to shop with a credit card. Just swipe the card and sign the bill and you're done. However, if your credit card details is leaked to a malicious third party, he or she can easily purchase goods from online stores under your credit. Hence this is not a very secure payment system.
Now let's consider the opposite end of the scale. Suppose every time you want to pay with your credit card the store needs to verify your identity by checking two official documents that identifies you (say your HKID card or drivers licence), as well as performing three separate biometric scans. Clearly it is now a lot harder for someone pretending to be you using your credit card, but at this point I suspect you wouldn't want to use your credit card either due to all the hassles.
The above is of course an exaggeration of what might actually happen in practice, but it illustrates an important principle, that although security measures reduces the risk of losses, it imposes its own costs. Thus it is not wise to blindly put in place any and all security measures you can think of into a system, because the cost of performing these extra steps becomes higher than what you lose by being less secure. The art of security, therefore, is to find the point where cost is minimised rather than engineering the most secure (and likely most tedious) system.
This is not to say one cannot improve security without causing extra trouble to the customers. For example, one of the biggest reason people don't (in the companies' view) adequately secure their PINs and passwords is because they want to share them with several others whom they can trust. We all do that at some point in time, and sometimes it makes sense to do that. Usually a more secure system means it's harder for people other than the account owner to gain access. But this contradicts with our needs to sometimes let people we trust to access our accounts!
In theory, if the system knows the owner gives (or would have given) another person consent to access than it should be safe to allow access for that person, but this is almost impossible to implement without increasing risk. If I want to access my mum's back account, should the bank let me? Let's say my mum give me permission today and I got in, but I try to get in again the next day. Does the bank let me in now? Can it safely assume the situation will not change in just one day? No! It needs permission from my mum again. But if my mum is always around to give permission she can just access the bank account herself!
If the bank has perfect information it will just let me in, but it doesn't. The best it can do is look at my track record and assume that I'm benign because I always have a good relationship with my mum. Again this is a tradeoff -- set the criteria too loose and anyone can access the account, too strict and we're back to where we started -- and the trick is to find the point that minimises hassles and risk of fraud. Realistically I can't imagine anyone building this kind of system just because it's so complicated and so hard to find that "middle point". That's unfortunate, because it means legitimate people like me have to "hack" into my mum's accounts just to change a credit card number.
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