2007
05.30

Calvin and Hobbes…

The animated version.

2007
05.28

Green card…

So thats why I am not getting my green card – its being supplied by a Ponzi scheme. Wonderful.

I have a suggestion – let the Ponzi scheme give me the green card NOW, and I would pay an extra 200$ in taxes every year while I have the green card.

Oh my god, I used the ‘T’ word. Now I am really going to burn in the tax-cut hell.

Not clear if it is better or worst than green card hell. So sorry, for the american audience, I meant green card blues. Of course, I could marry an American (but even that does not really help, BTW).

Now I realize my application process was completely wrong.

Oh well, all these worries seems so small compared to real problems that real people have, but still it is irritating as blues…

2007
05.27

Comment on Korea 10 – Is it a tea or is it a jam? by JS

I tried the jam out this weekend – it is delicious.
Next in line, kimchi pizza!

2007
05.27

Korea 11 – Oilbanks

Consider the following sign:
oilbank
in a gas station in S. Korea. Dont you think that a sign like that would cause a riot in the US, especially with the uproar about “outrageous” gas prices?

The only way to make this sign worse in the US context, would be to add in the bottom a line saying “We love your money!”

2007
05.26

Comment on Korea 10 – Is it a tea or is it a jam? by Maverick

Citrus tea is indeed one of the best things I have discovered from the Korean grocery store! You can even spread it on top of toasted bread. !😛

2007
05.26

Korea 10 – Is it a tea or is it a jam?

A local way of drinking tea is to buy (or make [or steal]) a special jam (it looks like a jam, it tastes like a jam, it smells like a jam, but yet it is not a duck). See for yourself:


Now, you take an empty cup, put a big spoon of not-duck jam in it, add hot water, stir counterclockwise, while chanting “death to all those who would whimper and cry”, and then drink it. (Of course, the stirring is optional, but the chanting is a must if you want a tea of the highest quality.)

Recommended.

2007
05.25

Korea 9 – Some history – the fall

Korea under the Joseon dynasty lasted from 1392 – 1910, over 500 years. Suffering invasion from the Japanese and Chinese. A remarkable historical achievement. This kingdom elite was using Chinese and getting a position in the government required passing torturous exams in Chinese, which you could prepare for only if you were well enough of to begin with, and literally had the right ancestors (lineage was everything [a window could remarry, but her children would not be able to take the exams]). Culturally, the Korean saw themselves as part of the Chinese world order, considering the China to be the center of the universe.

Following the wars with Japan in the end of the 16th century, Korea closed up to foreign visitors. A limited trade went on with Japan on a designated island, and relation with China were somewhat limited. And so Korea became the Hermit Kingdom.

Closed for so long, fanatically Confucian, slowly but surely the system got corrupted. To begin with, the kingdom was ruled by the Yangban class (officials), which were being supported by the rest of the people, which were of a lower class (i.e., majority of the society working as farmers). Next, the central government, was weak compared to local aristocracy, which in turn lead to inability to collect taxes effectively, and corruption, as bribing the tax man was cheaper than paying taxes (which lead to insane taxes on the people that could not avoid being taxed).

And so, when the west came knocking (>1860), the country was weak and unable to respond to tides of the time. Repeatedly, the Koreans responded by “leave us alone” to any effort to foreigners to contact them. The Koreans were quite vigilant in rejecting such intrusions. The General Sherman Incident is a good example – an American trading ship entered a Korean river (1866), demanded trade, was rebuffed, opened fire, and was immediately destroyed.

Compare this to Japan, that also closed up, but still had trading station with the Portuguese, thus still having western technology trickling in. Then, when the west opened up Japan (see here – opening up meant signing unequal trade treaties), a powerful and aggressive reform kicked in, turning Japan in 30 years, from a backward country into a regional power, that had beaten both the Chinese and Russians in war. Of course, this opening to some extent was motivated by the militaristic mindset of wanting to have a strong army (this in turn lead to Japan own situation that was not necessarily to Japan’s advantage).

So, naturally, Japan also wanted to become a colonial power, and Korea was just there for the taking. And under the pressure of Japan, Korea had to open up. Competition with China and Russia, did not stop Japan to take over slowly but surely, till in 1910, Korea was under total Japanese control. Korea would be independent again, only when Japan lost WWII in 1945. Interestingly, Koreans elites knew that they were in deep trouble, but they were a fish out of the water, clueless and too weak to prevent the loss of independence of Korea. A grassroots rebellion to kick out the foreigners just hasten the process of the Japanese taking over.

Japanese had abused Korea like any other colonialist power, but had also transformed Korea, by introducing better administration, heavy industry, roads, rails, trains, etc. By the end of this period Korea was well ahead of China and Taiwan economically. Of course, crediting the Japanese with any positive influence on Korea is a hearsay for Koreans. But it is doubtful if Korea would have progressed so quickly in such a short time on its own (the society was too conservative and inflexible to change).

This left Korea in an excellent situation to be devastated by the Korean war (1950-1953), which would be the topic of the next snippet of Korean history.

2007
05.25

Comment on McJob by Rafi

Trying to change the dictionary in order to force people not to think wrong thoughts … sounds familiar.

2007
05.23

Comment: “Korea 1 – Arrival”

New comment on your post #486 “Korea 1 – Arrival”
Author : Westwood College California Student
Comment:
I have been to many places around the world. It seems like many of the places I have been to are becoming more and more westernized. I myself am from the United States and developing countries are using us as their model. It sickens me to see that people are making their resemble the US. There is an old theme in some movies that I have watched, the elders know what they have and are happy with the way things are, the young ones always wants what’s new and fashionable and many times destroy the remnants of their old culture for something new. Good blog, i enjoy reading your posts.

2007
05.20

Comment on Korea 8 – Look & Feel by JS

Compare this to my Israeli experience of a high school that started at 8am and ended around 1-2pm, and which I had attended maybe 70% of the time in the four years I had been there.

… which landed you in Urbana-Champaign, where perhaps you follow the daily routine of Korean high school kids nowadays. Karma!

2007
05.19

Korea 8 – Look & Feel

1. Koreans are pretty uniform. All people have black hair (there was supposedly a period a few years back that women would color their hair, but somehow it became unpopular and disappeared completely). Hair cuts are pretty conservative – think Beatles.
2. A large number of people live in big apartment buildings. The bigger the better (18 floors is quite usual). A complex with several buildings is preferable to a single building. A building would usually face south (considered to be better). Thus, the city looks like a collection of thin tall boxes all aligned together. Here is how it looks like from space (somewhere in Seoul):
!Seoul

Namely, Korea is a computational geometer dream – an almost rectilinear environment.

3. Korean high school kids go to school around 7am, finish it in the afternoon, and then stay on for additional classes (when they would do homework and so on). The day at school ends around 11pm, when they return home (six days a week). Parents know their kids are still alive because of the dirty laundry. (Compare this to my Israeli experience of a high school that started at 8am and ended around 1-2pm, and which I had attended maybe 70% of the time in the four years I had been there.)

2007
05.18

Korea 7 – Misc

1. I lost my Camera. Did you steal it?

2. Went to a short 2 days trip to Seoul with Otfried. Was rainy and interesting.

3. Did you know that !\sqrt{\sqrt{\sqrt{\sqrt{\sqrt{\sqrt{1}}}}}}=1?

4. Bruce Cumings “Korea’s place under the sun seems like a good book on Korean history. More details when I finish it.

5. Did you know that the isoparametric inequality is an easy consequence of the Brunn-Minkowski inequality?

Ok. Enough vanity for now…

2007
05.12

Min Area Convex Polygon with k sides

Consider the following natural problem: Given a set **P** of **n** points in the plane, and a number **k**, find the smallest area _convex_ polygon that contains all the points of **P** and has exactly **k** edges. This is a natural question that was solved more than 20 years ago, and here I quickly sketch the (cute) solution and some key observations.

So, let **C** be the convex hull of **P**. Consider the unknown optimal polygon **S**. An edge of **S** is _flush_ if it contains an edge of **C**. Assume for the time being that all edges are flushed. Then it is not too hard to compute in (say) **O( n5)** time (but faster time is possible with a bit of thinking, but heck, I don’t care – I just want a polynomial time algorithm right now). Indeed, the recursive problem would be specified by two edges of **C** and a number **k**, and the answer would be the smallest area chain with **k** edges which starts and ends at these two edges. Now using memoization the above running time follows.

Unfortunately, morosely, dejectedly, wistfully, sorrowfully, dolefully, grievously, gloomily, joylessly, dismally, and cheerlessly, it could be that there are edges in the optimal solution that are unflushable (not to be confused with the other interpretation of this word).

Here is how an unflushable edge looks like.

!unflushable edge

We are assuming that the two edges adjacent to the unflushable edge **e** in the optimal solution has their supporting lines intersect on the other side of **e** than **C**, as in the figure. Note, that there is at most one unflushable edge which is not of this type for **k>3** (since the turning angle along the boundary of **C** on the two angles adjacent to **e** is more than **pi**). So, let us show that an unflushable edge (of this type) can be flushed.

The first observation is that an unflushable edge, must have the vertex it hinges on, smack in the middle of the edge **e**. Otherwise, we can slightly (aka infinitesimally) rotate the edge into the polygon **S** into the longer side of **e**.
!middle edge
As any half a moron with a quarter of a brain who is not blind can see, the area of **S** shrinks (if you are not a moron, then well, you would just have to find one to explain this to you). This is impossible, as **S** is the minimum area solution.

So, consider the case when the hinge point **p** is in the middle of the unflushable edge **e**. Let **h** be the line supporting the counterclockwise edge from **e**, and reflect it through **p**. By reflectionism (a common early Greek belief that stated that if you reflect a vertex of an edge through a point in the middle of the edge, the image of the reflection would be the other endpoint – this is sometime confused in the literature with Pastafarianism), the reflected line **h’** passes through the other endpoint of **e** and it is parallel to **h**.

!middle edge

Now, rotate **e** slightly around **p**, say clockwise, and consider the new area:

!middle edge

We lose the green area, but gain the yellow area. But by reflectionism (again, not be confused with the invisible pink unicorn), we have that the green area is larger:

!middle edge

So, again, we get a smaller solution than **S**, which is impossible. (Surprisingly, the same argument works if you rotate in the other direction. Namely, **S** is in fact a local maximum of the area, as far as rotation around **p**.)

Thus, there are no unflushable edges in **S** of this type.

But there is at most one unflushable edge in the optimal solution **S** that is not of this type if **k >3**. (For **k=3** we can get a triangle with all three edges being unflushable – but this is an easy case that can be handled by a direct approach.) It is now easy to modify the dynamic programming to handle this case, by guessing the hinge vertex. We conclude that in polynomial time (say **O(n7)**) one can compute the smallest area polygon with **k** edges,

For people interested in more details (and way faster algorithm), see here.

And now that I am done with this blog entry, I can start looking for Russel’s teapot – the poor guy didn’t have tea in like forever.

2007
05.09

Korea 6 – The way of the Kimbab

Many of you might follow the way of the samurai, but here in Korea other ways are preferred. A Kimbab is a roll of rice (bab) wrapped in seaweed (kim). There is a filling inside the rice that can be anything. The concept is remotely similar to Sushi, but usually it is bigger (usually in the size of a hotdog bun, usually sliced into rings once it is made). It can be bought in stores that specialize in making it and it is fun watching them being made, but a more “inferior” triangular version (Simka) can be bought in most convenience stores.

This Kimbab has a shelf life of about 24 hours (thus, the label on the Kimbab tells you the **time** when it expires), and as such it tends to be fresh. The rice contains a small filling which might be Kimchi, or whatever. It is the equivalent of the western small sandwich but it tends to be fresher (and better on average). It would be nice to have this in the US, but I do not think the demand is there yet.

Overall, Kimbab is quite cheap and it is a great light meal replacement. With no further fanfare, I present to you the way of the Kimbab.

2007
05.07

Comment on Korea 5 – Some early history by Sariel Har-Peled

New Jersey is in fact a better comparison, since its area is better defined. Although, as far as I know, the only second coming that happened in NJ, happened to Julie Katz, and she claimed that “New Jersey was only slightly better than hell.”

2007
05.07

Comment on Korea 5 – Some early history by Ken Clarkson

“Culture moved from China into Korea, and from there into Japan.”

Not only that: it is an “open secret” that the Japanese royal family is of Korean descent.

Also: to put the discussion in terms of the region that is the universal point of comparison: Israel is a little smaller than New Jersey, has about 3/4 the population, and maybe half the GDP.

2007
05.07

Korea 5 – Some early history

(The following is my interpretation of the history of Korea. It is hopefully accurate, but it might not be so.)

**Geography**: Korea is relatively small (South Korea and North Korea are each about 5 times larger than Israel, with North Korea being slightly larger). South Korea has about 49 million people, then north somewhere between 15-22 million (nobody really knows). South Korea has a western economy with GDP (per person) on the par with Israel. S. Korea is quite dense (about 25% denser than Israel).

The country is very mountainous in the north, where it shares a long border with China and a short border with Russia. The border between North Korea and South Korea is along the DMZ which is just north of the 38th parallel.

**History**: Korea for most of its history was a pawn in a game played by greater powers around it. The Silla kingdom started in the south of Korea and expanded to the north. Reaching an agreement with China (which grabbed some part of Manchuria north of Korea) this Kingdom unified the current day Korea into a single country around 1312 BI (Before Internet = 668 AD).

Korea was occupied by the Mongols around 1273 – but this required a long and costly six campaigns, in the end of which the Mongols accepted the fact that Korea would not be directly controled by them.

Culture moved from China into Korea, and from there into Japan. As such, Japanese were viewed as primitives by Korean. The first real trouble started in 1300s, when the Mongols tried invading Japan from Korea (after occupying Korea) twice. In both cases, luck, stiff resistance by the Japanese, and really bad weather that sank the invading armada (twice) saved Japan from invasion. (The “holy” wind that saved Japan from invasion, is called in Japanese Kamikaze.)

At the time, Korea was a unified country with vassal connection to China (an over simplification, I know) – elaborate gifts were given to the Chinese emperor every year (but he gave back gifts that were not quite as large but still significant). The understanding was that Korea would be helped by China in a case of need.

And now we move forward to 1590s when Japan – unified for the first time after a hundred years of brutal civil war (already using western arquebuses [guns]) – worried by the unemployment of its samurais, decide to invade China. The Japanese ask nicely the Korean king to let their army pass, who (naturally) refused. And the Japanese happily invades (twice). Brilliant victories in the sea by Yi Sun-sin, and Chinese help caused the Japanese to fail.

Korea than closed itself to the world (staying in connection with China) and trading with Japan in a limited way. No Europeans were allowed in, and Korea stayed closed to the world till 1880s, where our story will continue.

(You got to love countries that close themselves from the outside world for hundreds of years. Kind of simplify history. Just think about how world history would have been simpler if Bismark would have closed Germany for the outside world for, say, a hundred years, just in time for the first internet cafes.)

2007
05.03

Comment on Steam your algorithms and eat them too by Sariel Har-Peled

Not at all – remove the trivial and nothing would remain.

2007
05.03

Comment on Steam your algorithms and eat them too by JS

Like Bush, you trivialize and drivel.
Like Bush, I know, you will expunge.

2007
05.01

Comment on Steam your algorithms and eat them too by Piotr

For the sake of completeness, let me mention that the August 24 withdrawal will not be complete. Some of the troops will stay in a semi-permanent base established in Denmark, called MADALGO.

Think about GITMO, but for graduate students and postdocs. Of course, the residents will be returned to society after completing the re-education process.

2007
05.01

Steam your algorithms and eat them too

See here for a new school on this important emerging topic.

Like Bush I am shocked that they tell the enemy at what time they plan to start withdrawing from the school (August 24). I much prefer an open ended school that would end only when democracy and freedom would role Denmark, instead of the current oppressive regime.

2007
05.01

Kidnapping and failure…

There is an interesting article by a journalist that was kidnapped in the Gaza strip.

There is also a new devastating report on the Israeli prime minister and government functioning in the second Lebanon war. This probably would lead to the PM quitting his job.

The difference in the handling of this compared to the handling in the US of the failure in 9/11 and the “not lost” war in Iraq reveals something deep about a lack of flexibility and responsibility in the US system.