Noam Chomsky visit

A couple of weeks ago, Noam Chomsky, the active and famous intellectual - now over 80 years old, visited the campus. It generated a lot of excitement. Actually I suppose I should say "supremely active": after all, he has published over 100 books and is the most cited scholar in the world still alive.

He gave two free public lectures, a general lecture titled "Education for Whom and for What?", and a more specialized lecture on the topic of "What is Special About Language?"

This was evidently quite an event for Arizona. From outside my office window, I could see long lines of people all afternoon, hours prior to his 7pm general lecture. He filled Centennial Hall (capacity 2500) plus two additional overflow lecture halls.

Arizona Public Media, which runs the local PBS tv and KUAZ radio stations, taped the lectures. Here are the links:

• Education for Whom and for What?
• What is Special About Language?

I was fortunate enough to be able to chat with Noam on two occasions during this visit.

(Picture courtesy of Samantha Wray.)

Y&T S-27 table tennis robot

You go back, Jack,
do it again...
wheels turning
'round and 'round
You go back, Jack,
do it again...

I have a Y&T S-27 programmable table tennis robot.

It is a high-end robot made in China. In 2010／2011, it was considered state of the art. I bought it in Zhongshan (中山), China back in 2010 and had it shipped home.

I only take it out about once a year because I prefer to play with people. Human beings have more natural variation, which can be both a blessing (helps train adaption) and a curse (inconsistency). The other big problem with the robot is that it doesn't have arms: you cannot see it swing at the ball like a human being. A large part of anticipation is seeing how the opponent reacts to and contacts the ball. With the robot, the balls just shoot out almost without warning from a tube.

Last night, for the first time in over a year I used the robot to do a drill. (Usually, I'm fortunate enough to be able to find players to come out and hit with me.)

I programmed a drill asking the robot to send alternately one topspin ball slightly to the right of the centerline (position 7) and one to the forehand corner (position 10). One from each physical robot head. I asked it to send 40 balls and stop. (As the video belows shows it actually sent 41 balls.)

The way these robots work is having a spinning motorized roller shoot balls from a tube. The more sophisticated robots use two rollers. The spin and speed of the ball is determined by two (orange colored) spinning motorized rollers: one that brushes the top of the ball and one that brushes the bottom. You get topspin if the upper roller spins faster than the lower one, and underspin if the lower one is faster.

I set the top motor to speed 6, and the bottom to 1. This means the balls comes to me already loaded with topspin. The higher the speeds, the faster the balls.

The frequency of ball delivery was set at the 2nd slowest setting. This produced balls at the rate of 1 per 1.75 seconds. That gives me plenty of time to recover between balls, and perhaps approach the ball a bit more deliberately instead of frantically trying to keep up and reacting like a headless chicken. And as I get used to the drill and learn to anticipate the ball, cognitively I'll be less overwhelmed, and be able to work on improving my form. At least, that's the theory...

The control panel settings are shown in the picture below (left side for left head, right side for right head):

I'm currently trying to retool my forehand loop stroke. In the following video, I'm practicing my counterloop; that is, I return the incoming topspin ball with topspin. Fight fire with fire, so to speak. I'm only partially there. I'm trying to backswing less these days. This saves precious tenths of a second. And I'm think I'm finally succeeding in this aspect.

(There are other strokes possible. For example one could simply block the incoming topspin. Especially if one has less time. See my earlier post and video with Crystal Huang here.)

Also, having the robot send balls alternately to different positions helps me train my feet to respond properly. I have to move. And keep my balance. Loop. And then not have my loop stroke throw off my balance because I need to respond to the next ball. Multiple small hops are vastly preferable to a single larger step because this allows for fine-grained adjustment. You'll be surprised how many hops are possible in half a second.

Maintaining balance conflicts with how strong you can counterloop. The momentary stop for balance on the right leg, and the waist twist and weight transfer are crucial aspects of this part of the counterloop equation. Although my loop percentage rate is satisfactory, judging by the video clip, I could improve quite a bit on the quality of my loop.

Link: here

Moreover, my followthrough is not where I want it to be at the moment. This affects the amount of power delivered tremendously. It's way too much to the right, crossing the imaginary centerline of my body. Where the stroke finishes also affects recovery time. This is a stroke error. Instead I'd like it to finish with the paddle more out to the front. Technically, I also need to work on holding onto the extended stroke position momentarily at the end of the stroke. I automatically drop the paddle at the end of stroke which prevents proper transitioning. This is another error.

These are all good reasons why you want to resist the temptation of setting the machine to shoot as many balls per second as you can cope with. It makes good sense to debug the stroke fully before increasing the tempo.

In summary, the robot is not just useful when you can't find anyone to play with, it's also a good tool for reprogramming muscle memory. The problem of course is making sure the new program being written is a true fundamental improvement over the old. That's where video analysis is extremely useful.

A lesson with Crystal Huang: two left feet

This is the third entry in my continuing series about learning table tennis technique with Crystal Huang, a professional table tennis coach. These video clips were taken at the LATTA last weekend. (Previous entries can be accessed here: #2 too many degrees of freedom and #1 structural reform.)

Have you ever had the experience of attending an aerobics class at the local gym but came away discouraged, feeling utterly unable to follow the moves? If you understand what I'm referring to, you might empathize with me. If not, I envy your natural talent.

The video here will demonstrate that I am a particularly embarrassing example of two left feet. Since footwork is paramount in table tennis, this is a very big developmental challenge: a potential showstopper. In fact, it will become apparent that I can't even figure out a simple two point five step move even when it is repeatedly demonstrated right in front of me. Thank goodness for computer software, only when I viewed it frame by frame did the proverbial lightbulb go off in my head.

The specific challenge here is to move in correctly when the ball is played short to the forehand. Generally speaking, we have about 1/3 of a second to respond appropriately. Proper footwork is essential to getting in close enough to execute a decent flip, smash or push stroke over the table. Possessing a good stroke is useless without the necessary accompanying footwork. Rather like being all ready to ski without an appropriate vehicle to get you up the slippery snow-covered roads to that mountain that looks so good in the distance. Not sure that's the best analogy but, in table tennis, speedy footwork is needed to deliver us in about 2/10ths of a second close to where the ball bounces while retaining good body balance. And proper balance is needed to support good stroke execution and facilitate recovery.

Because this is all about movement, let's go to the video directly. We begin with the following drill:

Here the instructor stands at the top right corner of the diagram. The ball is blocked randomly to my backhand and forehand. I'm having trouble getting close to the forehand ball, especially when it bounces short near the net.

I have taken the liberty of adding commentary and translation where appropriate so you can follow Crystal Huang's instructional style. (For those who prefer to skip forwards, minutes 8:19-9:26 is where I'm utilizing the footwork in point play.) Also, since the video is a bit long, you might want to click on the "I" icon and set the resolution to 360p for a faster download.

Link: here

As should be clear from the video, my clumsiness resulted from my lack of understanding of how to perform the step, stop, step sequence. That is because I didn't understand what was really happening in real time. For those as translationally challenged as me, let me offer the following frame-by-frame explication. Thank goodness for video editing software.

(A)

(B)

(C)

(D)

(E)

(F)

(G)

(A) is the starting position.

In (B), body weight is shifted to the right.

This unweighs the left foot, which allows it to move towards the right foot, as shown in (C).

You can then stand on the left foot in its new position, and unweigh the right foot. This is shown in (D).

Then it's just a matter of picking up the right foot and placing it in under the table. This is exhibited by the sequence (E) through (G).

Notice the racquet arm does not move until (F) and (G). In other words, you don't backswing first and move later.

At (G), the weight is transferred to the right foot. Next, we need to lean the upper body over for reach when the ball lands short or close to the net. The left foot may go back a bit to counterbalance the torso lean. The free arm is often also used for this purpose.

Finally, one more critical point that may not be immediately apparent to some ping pong students is the fundamental idea to always pause momentarily and re-balance first after moving before hitting the ball. In this case, this would be just after the lean over from (G). That slight pause for balance makes all the difference in the world in making the push or flip stroke crispy (my terminology), i.e. much more effective.

If you need it, here is the video version of the frame sequence:

Link: here

A lesson with Crystal Huang: too many degrees of freedom

This is my second blog entry in this series about learning table tennis technique with Crystal Huang. For the first entry and a description of the motivation and goals of the series, see here.

The human arm is said to have 7 degrees of freedom. At the shoulder, we have 3 of those 7 degrees: up/down (i.e. pitch), left/right (i.e. yaw) and the ability to rotate (aka roll). The wrist is independently capable of pitch, yaw and roll as well. That makes 6. Finally the elbow has a single degree of freedom (pitch). So if you like, there are 7 positional parameters to the system.

When you perform an arm stroke, the number of parameters in the system multiplies. For example, we now have acceleration of the various parts of arm to take into account. Then factor in timing, and the position of the torso, center of gravity and feet placement. Add to that subtleties of ball contact and feel, and adjustment for the speed and spin of the incoming ball and where you intend to place the return, and you can see how sometimes it's difficult it is to reproduce a stroke even when we have it demonstrated for us up close and live. Anyway, that's my excuse for being a poor learner.

In the following video, I'm trying to learn a new forehand push stroke. The idea is to be able to receive the underspin (or sidespin) ball with the forehand side of the racquet, control and send it to different positions on the table reliably. I already have a forehand push I've been using for years, it's just not a good one.

The day before the video was recorded last weekend, I had about 15 minutes of instruction on the new stroke. Unfortunately, I confess I didn't truly "grok" or properly understand how the stroke should be executed. Even having the correct stroke demonstrated to me didn't trigger how it should feel. I was still not executing it well.

As this video clip shows, Crystal (after shaking her head) ended up coming around to my side of the table and moving my arm for me. This reduces the number of degrees of freedom of the arm to zero. And only then did I really understand what the stroke should feel like.

The video also contains captioning that I've added of Crystal's instructions during the session. This might be of interest to other table tennis students.

The video clip ends with me using the new forehand push to return service to different parts of the table. And then playing out the point.

Link: here

A lesson with Crystal Huang: structural reform

This is the first of a long series of posts about improving my table tennis. This is not about beautiful technique. There are plenty of videos on youtube for that. It's about my struggle and probably quixotic quest for better technique. More precisely, it's about structural reform. In other words, engineering out already-learned but ultimately flawed and limited strokes. Undo, then redo. The goal is to override muscle memory and replace with better programming.

Structural reform is a term I hear a lot nowadays: especially, with respect to the current eurozone crisis. Old habits die hard but countries have to change their ways. Growth, if possible, is the preferred way out. If not, austerity to shrink the economy is the only option left. Seems like it's either grow or wither away and lose maybe decades.

The same seems to be true in table tennis. We have a few tenths of a second (usually around 1/3 of a second) to react to the incoming ball and do something about it. Therefore, a lot is dependent on muscle memory. Human muscle memory is reliable and responses can be deployed almost without conscious thought. This is all and good given proper training and conditioning.

Unfortunately, some amateurs such as myself, without someone to nip flaws in the bud so to speak, spent years hitting balls incorrectly. This not only looks bad but also limits performance. After improving muscle memory through repetition, the amateur improves until he/she plateaus, unable to break through to the next level no matter how often they practice.

The next logical step then is to employ a professional coach who can highlight weaknesses and point the student in the right direction. A good coach can both demonstrate proper technique and explain why and how to execute the proper stroke. Unfortunately, the amateur has spent considerable time "grooving" his strokes and that subconscious muscle memory that enabled him/her to respond in 1/3 second is now a huge barrier to change. Reprogramming muscle memory is incredibly difficult.

The amateur then rues not employing a proper coach from the first day he/she picked up a paddle. Short of being reborn and learning proper technique under close supervision as a child, the amateur faces a long and frustratingly difficult road in overcoming his initial self-learning or natural programming. Watching videos of world champions with beautiful technique doesn't really help. The gap is too large. Even seeing what seems like humanly possible proper technique up close and live, subtleties escape the observer and attempted replication results in just a pale and unreliable facsimile of what he/she just saw.

The amateur may be missing crucial knowledge. But even possessing the correct knowledge doesn't seem to help as much as he/she thought. Low level programming seems unavailable or strangely elusive to conscious thought processes.

On this beautifully sunny past weekend in Los Angeles, I decided to spend 15 hours indoors at the LATTA to take lessons with Crystal Huang, a professional who went to the Beijing Olympics on the USA national team. Retired from competition, she is a coach. (I've blogged about the club before here.)

I decided to get more serious about structural reform, so I recorded a lot of video over a weekend. Just merely taping a coaching session doesn't really do much. So I started editing the videos into clips to remind myself of what to do (as well as what to not do). It became a labor intensive process because I found myself adding captioning as an aid to understanding. So I thought I might as well share. Perhaps some of these may be of use to others, spark a change or two, or at the very least make the reader feel thankful their game doesn't include my huge set of flaws.

Next time, we'll look at how Crystal tries to point out and correct my many flaws. This time, I'd like to show how even the warm-up (before the lesson truly begins) can be very revealing.

This first video is of my forehand block. Crystal is gently topspinning (or looping) the ball to my forehand. The rate is almost exactly 1 ball per second. I know precisely which quadrant the balls will fall in. In fact, I only have to worry about blocking that ball diagonally back to her forehand (she is a lefty). I block the ball back 33 times consecutively in the following clip but, as you can see, I still manage to screw things up.

Link: here

The fundamental problem is I'm not constantly moving to track the ball. I'm reacting too late (ball is about to arrive), and having to move off-balance and attempt to correct and rebalance in record time. By block #34, I've lost track of my center of gravity and clearly it looks rather ugly.

Slow motion of block #15 is rather revealing and will make the problem clear. See captions in the clip below.

Link: here

Tellingly, because I had to lunge I was unable to block the ball back to her forehand corner. Instead, notice the ball went to the middle of the table. You may not have noticed that she smoothly moved across and still looped the ball to my corner so I could continue.

Here's what went wrong.

(a)	(b)	(c)

In (a), the ball is looped. I haven't yet noticed the ball will end up out of reach. (I should have observed the angle of the paddle and reacted by shuffling to the right. In fact, it's critical I do so.)

In (b), 0.26 seconds later, the ball is landing on my side. Too late, I realize it's out of reach. I've wasted 0.26 seconds without moving my feet.

In another 1/10th of a second, I lunge with my arm as the ball arrives. Although I get to the ball and return it, it's just a mere band-aid. Actually, the situation is quite dire.

As a result of the lunge, I'm way off balance as shown in (c). Instead of sensibly moving sideways to the right earlier, now I've created an unnecessarily enormous backlog of work for the next 0.6 seconds.

I have to land away from the table, regain balance, push off again and hop back towards the centerline, rebalance myself and hope I get there before the ball arrives again. Despite the leisurely 1 second interval between balls, I barely got back in time.

And of course, my mistake is actually deadly in practice. Had the drill been not just to my forehand, the ball could have been looped to my backhand corner. In that case, there is no way in hell I could have gotten back in time of course.

A keen observer will notice there are other systemic problems that I haven't mentioned. For example, notice I automatically drop my arm after each block. This is another very bad habit that will cost valuable tenths of a second.

Hong Kong wishes

There is a certain beauty and a romantic feel to Hong Kong, especially in the relative cool of winter. I can't be sure I'd ever want to live there, but a visit can be simply sublime. Tonight and every night Let's go walking down this empty street Let's walk in the cool evening night Wrong or right, be at my side The downtown lights...

I need a good walk after dinner; this is from an uncrowded Avenue of the Stars (星光大道) around 10:45pm. I was very lucky indeed; I had just seconds to compose this as one of the few (fake) junks still in existence came into view and made a brief stop.

(Handheld pictures at night can be tough to nail. You need a fast lens (here, wide-open at f/1.7) and as slow a shutter speed as you dare: a potentially blurry 1/30s was used here. Fortunately, the Olympus E-P1 has in-body sensor stabilization. Still, this exposure required a speed of 3200 ISO! No EV compensation. My EP-1 is truly marginal at high ISO. Hmm, a good excuse to get that new world-class Olympus OM-D.)

Not being much of a tourist, my ideal day in Hong Kong would revolve around guilt-free food and exercise. The idea being to pay one's dues before taking in a calorifically significant repetition, for example, of this:

Add in some shark fin soup beforehand, and ahem, you see the need to walk it off a bit before I can fit in that relaxing drink, maybe at the nearby and classy Intercontinental Hotel Lobby Lounge (Link: here)?

Or for a view from on high and a different ambiance, maybe the inside/outside Cocky Bar up on the 18th floor at The One? (Link: here.)

Of course, to ensure that one should be feeling absolutely guilt-free about the after-dinner Mojito, I'd suggest sweating a bit for a few hours before dinner: for example, I'm partial to exercise of the kind shown here. Your mileage may vary.

Win a few, lose a few, don't play too hard and make some friends. And, before that, if I manage to catch up on a few hours of work on the laptop in the early afternoon, then Life with a capital L is good (at least for today).

Unfortunately, there is a different kind of price to be paid for those sublime evenings.

The problem with travel across time zones is jet lag. I wake up early. There's nothing I can do about that.

Since I'm up early, I might as well take out the iPod and running shoes that I've brought along.

Hit the hotel gym for a light 30 minute workout before first light, as the city is still sleeping. If I time this right, by the time I finish, dawn's light has transformed my view of the cityscape from 45 floors up.

It's 7:30am and I'm 450 kcal to the good already.

A cooldown swim in the deliciously deserted 20m long roof-top heated pool. I can concentrate on my technique as I swim slow lazy laps:

I skip the whirlpool for the (Japanese-style serious) 43C water temperature of the indoor spa:

It's not onsen (温泉) water with mineral content, but as my leg muscles warm back up, I feel them slowly unwind. I may also use the steam room. In the USA, they may use peppermint in a plastic spray bottle, in Hong Kong it's Cassia bark bundles on the heater in the steam room. (Therapeudic effects are claimed. Balances ying and yang. Restores energy, improves the digestive system and eyesight. Or so it says. I'm sold. It feels good.)

(Nearly perfection, much classier than what I'm used to normally, I do wish they had laundry service for my running gear while I swam and unwound in the spa.)

By the time I shower, it has been an indulgent two hours since I got up. But hey, the silver lining with jet lag is that time is on my side in the mornings. With additional good timing, I'm ready for dim sum breakfast as soon as a decent restaurant opens.

I love to be first in a nearly empty restaurant. You see, near emptiness and tranquility is at a premium in Hong Kong. Congee (粥) accompanied by deep-fried, and slightly salted breadstick (油條), aka colloquially as 油炸鬼 (oil-fried devil), really hits the spot after the run.

Plus my favorite char-siu steamed rice flour rolls (豬腸粉) beautifully presented, and I'm good to go (back to sleep).

It's okay. It's only 9am, even if I nap, I've accomplished something today even if I'm feeling deliciously decadent.

Ping Pong in Hong Kong

I've never played ping pong in Hong Kong before: basically because I don't know anyone there. Instead, I've always gone into Shenzhen next door to play and get coaching as documented elsewhere in this blog.

(I know there are private clubs and municipal gyms for those who can book tables in advance, but I'm not plugged into the Hong Kong table table community.)

Well, all that changed this winter. Through networking, I managed to visit facilities at two universities in Hong Kong. In future, I'll definitely be playing at these locations whenever I get the chance.

City University

As the name suggests, this is in the "city" so to speak. Easily reached by MTR train (East Rail line) or subway (Kwun Tong line, 觀塘綫), Kowloon Tong (九龍塘) station, I played here twice.

My contact and generous host was Prof. Leon Zhao, head of MIS at CityU (pictured here on the left). Incidentally, I have met Leon previously in a professional capacity as we served together on a Ph.D exam committee, though I never knew he was a ping pong player. It's a small, small world, isn't it?

You need a guest pass and someone affiliated with CityU (in my case, Leon) to get into their sports centre. Cost is HK$20. There is a dedicated room for ping pong and nice new-looking tables.

They have a club and CityU team. Plus a semi-professional coach, Eddie Wei, standing to the right of me below:

(From left to right: Ye Liu (Ph.D student), Yikshing Yeung (CityU TT team member), me, Eddie Wei (coach), Haibin Yang (Professor), Wansan Lee (high school student who trains there, seems like 2500 level player) and Enyu Zhuang (Ph.D student).)

I had a lot of fun playing there playing with as many people as possible. Very cool bunch of guys.

Chinese University of Hong Kong

I also had the opportunity to play at the Chinese University of Hong Kong. With a large uncrowded campus up on a hill, this is not in the city by any means. It has a MTR train (not subway) station, simply called University (大學), on the East Rail Line.

So it's not surprising they have a larger gym with very high ceilings and good lighting. 6 tables.

Very spacious by Hong Kong standards, it's a nice facility with room to back up and lob a bit.

I played a bunch of professors but this guy pictured below is the staff champion. He's a PE instructor at the university. I tried hard but he beat me 3-0 convincingly.

You need to be affiliated with the university to play here. My contact and host here was Jimmy Lee, professor of computer science.

Like me, he is a computer science professor. We both play ping pong and train to run marathons. I even own the same exact ping pong shirt he is wearing. Obviously, a great guy with the right set of hobbies! :)