Saturday, October 1, 2016

What is the most difficult technical (physics, computer science, mathematics etc.) course you've taken or heard of?

EECS470 Computer Architecture and EECS427 VLSI, both at the University of Michigan, require at least 40-60 hours/week in order to merely pass the class. Unlike other classes considered to be difficult, being unusually smart will not help you here in terms of time spent, as the main project is what consumes all your time, not passing exams.

In EECS470, groups of 4-5 people design from the ground-up an out-of-order processor with the Alpha ISA in Verilog. Here is the project specification: Page on Umich

The baseline project is difficult, but probably "only" requires around 40-60 hours a week. However, as the performance part of the grade (20%) is curved to the class, there has been an "arms race" to see which group can design the fastest processor, ever regardless of year. Taking this arms race seriously probably resulted in 60-80+ hours of work. Back when I took it, it was impossible to avoid this arms race unless you were content with not receiving an A in the class although you could still get an A by performing extremely well on the exams. As a senior level course, EECS470 was also cross-listed as an introductory graduate level course, which meant that scoring well on the exams was a much more difficult proposition than in lower level courses due to the competition.

For those with no knowledge in processor design, an aggressive EECS470 project is similar at a high level to a commercial ARM A12 minus the uncore, some of the ISA-specific difficulties, I/O, coherency, and a heck of a lot of performance tuning. How is a team of 5 newbies supposed to design something that takes a team of hundreds of people several years to do so? Simple: Alpha is a very easy ISA, the EECS470 project is not optimized for area, performance, and clock speed, and most importantly: everyone's EECS470 project contains many bugs!


In EECS427 VLSI, groups of 4-5 people design, place, and route from the ground-up an in-order processor with a simple 16-bit custom ISA. The main difficulty is that the processor datapath is full custom, which means that every transistor is sized, laid out, and connected to other transistors by hand. For comparison purposes, in the UT Austin version of this class, only a small SRAM and an adder is assigned for custom layout. As in EECS470, there is again a major arms race in this class, but this is for a $1500 cash prize. Back when I took the class, my group participated in this arms race with gusto. The previous clock speed of 650MHz was held by the TA of the class. He smugly told us that it would be impossible for us to break this record. Of course, we took it upon ourselves to do exactly that, reaching a record-shattering 1.05GHz clock speed. In addition, we chose to implement 4-way SIMD as our special feature. Every member of our group worked for roughly 80-100 hours a week (a conservative estimate) solely on this project to make this happen.



To learn about how we did this, you can read our project report: Page on Appspot

Webpage about our accomplishment: EECS News

After that semester, the professor banned some of the techniques that we used, thus ending the war on clock speed and preserving our title for life :)

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How did one small decision change your life?

I went in search of an egg McMuffin.
 
As an undergrad, I attended college in the USA. Paying the expensive college tution at an unfavorable foreign exchage rate  pretty much wiped off my family's savings. After I got done, I applied to grad school. I got in, but without a Teaching Assistantship - which meant that I had to depend on heavily depleted family savings to cover my first semester at grad school.
 
My very first morning at the new college the international student director asked me where I would like to go have breakfast, as the cafeteria wasn't yet open. So I told him that I'd like to go to McD's and have an egg McMuffin. Well, as we were walking towards McD's, the director spotted another international student in my program and walked over to introduce me. "Go to the department SOON!", she urged me, "they are looking for a grad student to teach a class". This opening had come about unexpectedly, and I gladly accepted the offer on the spot.
 
Because I taught the class well, and earned good grades my first semester, I was awarded a full Teaching Assistantship that covered my fees and provided me with a stipend.
 
I graduated from this program and went on to get a second grad degree at a different school. After that I got a faculty job at a college that initiated my Green Card process. Now I'm a Permanent Resident and a tenured faculty member.

And it all started with hungering for an egg McMuffin.


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How did one small decision change your life?

When I was 19 I read a book called Shantaram by Gregory David Roberts, which inspired me to travel. Half a year later I quit my studies in Europe, went to China and started studying Chinese.

Now, 5 years later, I'm still in China with a Bsc and Msc from world-class universities. I've met thousands of amazing people, from CEO's to carpenters and each and every single one of them have taught me something valuable and have enriched my life.

I have travelled all over Asia, learned the principles of buddhism from Buddhist monks, fought monkeys on deserted mountain tops, sang communist songs with Chinese government officials, reached a high level of fluency in Mandarin Chinese and found a job that fits my future goals. I am also currently in the process of developing a start-up here in China and I can't wait what the future beholds. 

All because of this one book... and it wasn't even about China!


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If Legolas is much older and much longer lived, forever youthful, do these characteristics make him a better warrior than Aragorn who is mortal?

Aragorn was probably not the archer Legolas was; Legolas was probably not the swordsman Aragorn was. He didn’t even wear a sword, only a long knife. Aragorn is a bigger stronger guy than Legolas. Legolas has sharper eyes and better hands.

There’s a point beyond which training only keeps you sharp but can’t increase your capabilities any more because you’ve already maxed out your physical capacity. I think as of the time of the story they had both reached that point.



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Have you ever almost died and had something inexplicable save you?

I almost got hit by a train.

It happened when I was in the 11th grade. I was on my way home and I had to cross the railway before I reached the area. It was a two line railway that I needed to cross. Usually, the railway looked like this:

Usually there would be someone whose job is to  guard the railways and block the way when the train is coming so pedestrians don't cross it. Sometimes they will be tipped by people passing by.

So, that strange day, there was no one there. No motorcycle passes, no people around, I was alone. All of a sudden my head got full of stuff; it was so complicated I couldn't explain, I wasn't aware of my surroundings. I stopped in the second line of the railway and got stuck there, thinking of something that I can't even remember, I was completely distracted and my uniform skirt got stuck in between the rails (I wore  a long grey skirt as my school uniform).

Slowly I started hearing the sound of the train coming from the line. It was not a straight railway, it's a bit curvy, and that made it difficult to see if the train was really coming or not. I knew that the train would come, but I could not get oht of my head and could not move. Until I realized that my skirt was still in between, and I could see the front of the train coming. I was frozen.

I didn't know what to do, I knew it was late for me to run, it was so close. In the last moment, I heard someone's voice and it seemed that I had been pushed. I found myself lying on the ground, only several meters from the railway while the train passed.

I thought somebody helped me. I was looking around, hoping to find someone. I found no one...

I don't know what happened to me, but I am really grateful to whatever or whoever saved my life. If that happened only a few seconds later, I most probably would have died from the hit.



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Libertarianism: why do so many libertarians oppose open borders?

Imagine you are a partial owner of a shop that sits next to a border.  The border is closed, so the only shoppers are those from one side of the border.  The shop is popular with these shoppers, but the shop's pricing model is all messed up.  They sell items for $5 that cost $10 to make.  As a result they lose money on every sale.

Suppose someone then suggests opening the border.  Is this a good idea or not?

One could certainly debate this from many angles, but the salient one is that a shop with a broken pricing model, losing money on every sale, may end up losing even more money, and doing so more quickly, if it had many more customers.   That downside might override other positive aspects of the open border.

Until we have entitlement reform and reduce the deficit, the federal government is the shop losing money on every sale.  Encouraging new "customers" without fixing this underlying problem is asking for disaster.   However, once this is remedied, I think almost all libertarians would support open borders.  So libertarians do not oppose open borders, but they are not entirely ignorant about the relationship of open borders with entitlement reform.  Look at the recent immigration crisis in Europe, for example.   Open borders instantly lead to immigrants heading for the states with the most generous benefits.   This is simply a question of incentives.



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[SPOILER] In Interstellar, what happens to humanity in the end?

Humanity is saved because both Plan A and Plan B worked.  Cooper and TARS found the solution to the gravity equation in the black hole, and Cooper programmed the solution into the second hand of the watch.  There was already a plan to evacuate mankind into the rotating space colonies, but it couldn't be pulled off without the gravity equation.  Once Murph Cooper got the data from the watch, she could solve the gravity problem and begin work to set in motion the space colonies to evacuate earth.  Meanwhile, Dr. Brand, certain that all was lost, and having lost many years by orbiting so close to the black hole, went to Edmund's planet to settle and begin Plan B.  At the end of the film, we see her starting a new colony with the new people from Plan B.  She is unaware that the gravity equation worked and that people from Earth have been evacuated.  The movie ends with Cooper going out to find her, which will be the first step in bringing all of surviving humanity to Edmund's planet.

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