How to do Beta?

To have high enough confidence that the product will be good enough.

When company thinks they are done with the development of a new product, be it a new car, kitchen detergent, lipstick, or a piece of software. They would like to know if this product will really be successful in the market place. They would get a small number of real customers to try it before start selling. That is the famous “beta program.”

It turns out pollsters use the same technique to predict the election results. Surprisingly, a random sample of just a few thousand people can accurately predict the next president. This is a well-studied science, also long practiced.

How high the confidence is enough? There are two popular choices of 95% and 99%. How precise the answer should be? The “interval” is usually 10%. The “answer,” therefore, come in three numbers: for example “we will have 95% confidence that 65% to 75% will find it favorable.”

The real science is in calculating the sample size: how many do you need to poll to arrive at the answer? For that, we can Google “sample size calculator.” All of them ask you the size of the actual population, the confidence you wish and the interval that you can tolerate. With that, out spit a number: the required sample size. If you are too lazy to search, 400 is not a bad “go to number.” If you push it, 250 will work too.

Recently, we released a product with a beta program of less than 30 participants. At the end of the program, all of them were satisfied with the product and we released it to the general public. It turned out the product has a defect that affects roughly 5% of the customers. As our luck, none of the participants experienced the defect. Had we computed the required sample size, we would have known that 30 will yield such a low confidence level that this beta program is meaningless. It told us the product was good enough and, in fact, wrongly.

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Olympic Penisula

Few people realized that Seattle is probably more than 100 miles from the Pacific Ocean. On her west is the magnificent Olympic Mountain that, on clear days, I can see from my balcony. The snow capped shines brightly in the early morning and the sunset paints the western sky brightly with more colors than you thought possible. But, as a 5-year Seattleite, I never went, until this May day.

Why did I wait so long? And I will definitely go again.

Olympic is not a day-trip and a primarily a hiker’s heaven. I looked for more pampered sleeping and eating accommodations than tents. Lake Crescent is closer to Port Angeles, a small port town, and Hurricane Ridge, the must-go attraction for the Olympic National Park. I reserved Lake Quinault Lodge, planning to tour Tacoma on my way there. The idea is to circle the peninsula clock-wise.

LeMay Car Museum, shaped like a cigar-shaped race car in Tacoma, is a 4-story underground museum with hundreds of cars that are arranged in no discernible order. I was mostly drawn to those old and odd ones: Ford Model-T, elegant and impractical coaches, early battery-power ones, etc. It was a nice stroll for a couple of hours, longer if one would linger and study the exhibitions.
Morning view

We arrived Lake Quinault in-time for an easy hour-long hike at the rain forest. To me, who grew up in a sub-tropical island, rain forest is the most common thing: canopy trees, trickling streams, dripping mosses, ferns of all shapes and forms, insects and various life-forms. It was good to work up the appetite for the dinner at the lodge, the Roosevelt Dining Room. Its view was better than foods that were quite decent as well. It was peaceful, relaxing, and beautiful.
Ruby Beach

With a bit early morning lingering at the lake shore, we continued our journey. Ruby Beach’s giant rocks (or small islands) were mesmerizing. I can probably just wandering here for hours watching the waves and birds. Forks is the city for Twilight fans. Lake Crescent is similar to Lake Quinault with probably slightly better facilities. Around mid-afternoon, we arrived the climax of the trip: Hurricane Ridge.
Hurricane Ridge, Visitor Ctr

It was a calm and bright day, no namesake gust insight. We sat at the short stone ledge just to admire the Olympic mountain range and the distant glaciers. It was 45°F and snow were still on the ground, but the calm sun kept only a light jacket on us. We took a short hike to see Port Angeles and Victoria from a distance. It is the peak of one of the mountains, 5240 feet in elevation. The view was expansive and breathtaking. Had I had sufficient time, I would have taken up a longer hike to Hurricane Hill.
Bainbridge Island Ferry

Yep, Olympic Peninsula, I will be back.

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Should I try to become a CS major?

Got a question from a frosh in UCLA. It turned into an email conversation.

Q: As of right now, I am studying Math/Econ, but I was also considering pursuing Computer Science along with math because I feel like it is useful and I feel like coding is a good skill to have. I’m not exactly sure what type of career I want, so could you tell me more about your job, like what you do daily, some of the more stressful projects that you’ve done, what you like about it, what you don’t like about it, the company culture, and more. This would be really helpful in helping me decide what I want to do.

A: It is not a bad idea to have a BA degree in Math. In STEM (Science, Technology, Engineering, and Math), it gives you the most flexibility in grad schools.

When I was a software engineer, I spent the majority of my day “debugging” — trying to figure out what’s wrong with the code myself, or someone else, wrote. It is like playing detective or solving a big puzzle. It was frustrating if I cannot find the “bug” or when I realized that it was beyond me to figure out. I spent long, long days staring at the screen thinking hard to solve problems. We always had schedule to keep; the day-to-day life was quite stressful. When things worked, however, it was like magic. Everything fit together perfectly and was beautiful. Software projects typically demanded all my concentration. When I completed a project, it was like finishing a long run that was just beyond my range — exhausted, fulfilled, and accomplished

There are people who are smart but not having the aptitude for coding. Software development can be a very frustrating thing for them. Coding is a very consuming job, it takes efforts and long time to excel. You will feel like being part of a community that other people don’t quite understand what you do.

Most software companies are very competitive in culture. People are “cut throat” in trying to best others. But it is more like the competition in music or sports, and not like in wars. The real only way to win is to practice harder yourself, and not to harm others physically.

The world will need many software engineers for a very long time. So it will be a very profitable major.

If you are not pursuing a graduate program in CS, switching major gives you a good job prospects at graduation. To have a successful career as anything requires intense effort and pretty long working hours. But your finance, law, medical, or law majored friends don’t get paid nearly as well doing that.

Q: Did you like being a software engineer, though? Or did you wish that you had pursued something else? I am also hoping that in the future, I would enjoy my career and not regret not having pursued something else.

A: I am one those rare and lucky people that vocation is also the interest. Most software people either flame out in 5 years or stay with it for the rest of their lives. Truthfully, I probably don’t mind being a teacher. I am not sure if I could have taught for 30 years.

Q: Do you believe it would be easy for me to learn CS in grad school?
I do feel pressured into finding something now, as I could look for internships over the summers and to build a resume for a career in the future. I want to use my time productively so that I can make sure I will be successful in the future. Would I not be considered for internships?

A: I knew many non-STEM major who finished their CS master’s program in 2 years and had a successful career as a software engineer. Of course they needed to work hard during those years, but a math major has already a leg up. If you cannot get into the CS program, stay with math and take some basic courses to prepare for the grad school.

For the first two summers, most companies treat STEM major the same for internship. The third summer will be slightly different, by then, however, you would have two internships under your belt. So you will be just fine.

Having good internship during school is the best way to find job at graduation. So you are smart in planning for that.

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Droughts are Political Problems

California and Taiwan, two places that are close to my heart, are both suffering severe drought this year. Governor Jerry Brown is imposing mandatory water reduction. Taiwan is rotating water supply: two out of seven days will have no running water. Nobody is enjoying this.

Both California and Taiwan are adjacent to vast amount of water. Taiwan is also in a subtropical region that rainfall is several times the amount of water needed for the island. What they do not have is fresh and clean water that is also free and convenient. Simply put, they lack the will to solve the water problem.

So, politicians do what they are good at: blame mother nature and let people suffer. The people, on the other hand, insist on this commodity to be nearly free. Strangely, for something so precious to life, we refuse to pay for it.

A couple of years ago, I read the book The Big Thirst. What I remembered is two ironies: the unwillingness for politicians to fund water projects and the reluctance of people to use recycled water. They are ironies since politicians routinely fund projects that are far less impactful to people’s lives. Also, human beings, and all lives on earth, have been drinking recycled water since the beginning.

I knew more people, or companies, putting up solar panels on their roofs than collecting rain water coming down from the gutters. I know of no one who tried to reclaim the “grey water” that was used in shower and washing, but not toilets. I know of no desalination projects, or any new ones to store and transport water from far away. Jerry Brown and Taiwan government have but one plan: pray that more water will come from the sky.

And Californians and Taiwan citizens seem to believe that’s a fine plan.

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The Dinner

Two brothers went to dinner at an obviously high-end restaurant in Holland. Paul clearly dreaded this event and arrived early with Claire, his wife. A while later, his brother, Serge, arrive with his wife, Babette. What, someone wrote a book about this evening?

Yes, brilliantly, and it is a suspense thriller, not at all about foods.

The theme of the book is about manipulation: the attempt, the motivation, the plan, and the carrying-out. Here, the origin is actually family and love, and not some big political game. This brought everything to visceral level, yet with a mastermind. Very delicious.

Masterfully, Herman Koch, revealed the characters, their relationship, and the event that led up to the dinner. Just when you think you have known the character, he gave you a twist that made you gasp. Then, a hint that was casually mentioned became an important factor and you had an aha and a “everything clicks” moment. This is as good as Gone Girl in the way surprises were delivered.

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Caramelized Onion

First time, I sautéed and “blonded” them. Second time, it worked and they are delicious.

I like onion, whichever way to eat them. I eat them raw, mixed in with salad, onion soup, or whatever. Last time I had a steak, I added caramelized onion on top and it was excellent. Then I thought, “How hard can it be to make it myself?” A bit Googling and I experienced my first defeat. It was greasy, flavorless, and overall a bad experience.

First of all, non-stick frying pan was a mistake. The key to caramelized onion is to continuously develop those fond (those brown substance stuck to the pan) and deglaze (add liquid and scrape those fond off). A non-stick pan completely defeat the purpose. With that concept, the rest is really simply about patience.

Chop sufficient onion to fill the pan, add some oil, turn the heat low, and wait. Slowly, the onion turns brown. Slowly, they started to stick to the pan and that’s when the fond started to develop. Once in a while, add liquid, scrap off those fond, turn the onion, and wait some more.

Yes, the trick, if there is any, is to control the heat to not burn the onion and just caramelize them. Oil is less important than the repetition of liquid and deglazing. At the end, sprinkle some salts to enhance the flavor.

That’s pretty much it. I got the added appreciation to this dish, or condiment. It takes a long time and lots of attention to make.

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A Beijing Traffic Experiment

When T3 came alive before the 2008 Olympics, going to Beijing International Airport was a breeze. Hop onto the Airport Expressway, zip through sparsely occupied lanes, and you arrive at the majestic Terminal 3 in about 30 minutes. The most stressful factor is the way your taxi driver practices his race-car driving skills. Gone are those happy days. This 12-mile highway now routinely takes more than an hour to slug through.

Is the light-rail a better way? There will be no traffic and it connects to the subway system very well.

After bidding adieu to a friend who lived not too far away from the airport, I decided to experiment. (This is what a nerdy business traveler does on weekends.)

Instead of the usual taxi back to the hotel, I went to the airport. The plan is to take the light-rail, board Line 2 at DongZhiMen (東直門) station, transfer at the JianGuoMen (建國門) station to Line 1 after 3 stops, and get back to the hotel in another 3 stops. The cost would be 29RMB (about US$5).

I boarded the light-rail at 1:20pm on this lazy Sunday afternoon, pretty much the lightest hour that I can think of, and walked into the hotel room at 2:45pm: hot, thirsty, and tired. There were long walks to connect at both transferring stations. Even for a Sunday afternoon, Line 1 was packed, shoulder-to-shoulder style. I imagined myself dragging a carry-on luggage and a computer bag and was not pleased at that image.

The next day, I took the taxi to the airport: 45 minutes and 90RMB.

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An Alternative to Uber

In China, nearly nation-wide, there are many apps for taxi services. The two major players are 的的 (Dee Dee) and 快的 (Kuai Dee). As a passenger, you enter the destination and pick-up location to request a taxi service. All nearby drivers receive the request and bid to get the business, with the dexterity of their fingers. There is a standard “reward” of several RMBs for the winner, in addition to the fare. This reward may change by market condition. The passenger, however, always pays just the metered fare.

As my cab waited on the last light before the destination, the driver started to pay attention to the dashboard mounted cell phone. A request would flash by every 2 seconds or so. He had his finger ready to pounce, but did not. I became curious on why not. “Oh, these are not good fares and those are too far away from me.” As he pulled onto the curb to let me out, he bid and lost a deal. “No matter, plenty of businesses here.”

Uber is an adversary to the existing taxi industry. That forced challenges at legal, political, and economic levels. This “China model” co-exists harmonically. I have little reason to think that Uber will thrive here.

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Imitation Game

Alonzo Church first came up with Lambda Calculus, an obscure branch of mathematics that deals with the manipulation of symbols. Pretty much at the same time, Alan invented the (Universal) Turing machine, an ingenious construct that manipulates symbols with programs. Together, they formed the Church-Turing Thesis which basically defined how a theoretical computer can solve problems. This remained academic until John implemented Turing machines with the famed von Neumann architecture that led to all computers today.

Alan Turing laid the foundation for pretty much all computational devices today to exist. Oh, as the main theme for this movie, he also broke the German Enigma machine that helped win the war. Without him, millions more would have died, history might have been completely different than how it really became, and you wouldn’t have a cell phone in your pocket. Alan Turing should have been celebrated and revered as a man who changed the world for the better. Yet, he killed himself after being prosecuted for being a gay.

It was a wonderfully acted movie that did not bore people with how the Turing machine was made. Instead, it focused on the man, his intellect, and character. It was simply an additional bonus for a computer nerd to enjoy an obscure bit of scientific history that made it to the big screen.

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SiMaTai: the Sequel

Edit on Mar 16, 2015. Original post on Oct 2nd, 2008.

Must be due to the popularity of my original post :-), this section of the Great Wall has become more popular. For unknown reasons, the official has blocked the path from JinShanLing to SiMaTai. They have also “repaired” many part of the wall, at least for the SiMaTai section. The works include a newly made “water town” that imitates southern China scenery.

This is really a sad development. Yet another nice natural beauty ruined by commercialization. Sigh…


I hiked this section of the Great Wall just 4 months ago. No doubt it is the most challenging and enjoyable part of the Great Wall near Beijing. The views are spectacular, the breezes are soothing, the stairs are punishing, and the walls hide the thousand-year old secrets. This time, I hiked with two youngsters: my daughters. I wondered, the night before, if my regular 2-mile jogs can match their lightness and youthful regenerative speed. An old man will go distance spending a days with his daughters. I am the one with experience and wisdom. Right? Alright, experience.

Even I was here just 4 months ago, it is still breathtaking. We took the cable car up (100rmb for entrance and cable car) and turned left to start. There are 30 guard towers until the end. Since this wall is somewhat wild (what Beijingers call when the wall is not fully renovated), you see crumbled ruins everywhere. And that’s a great attraction. It feels real.

Half-way, we need to purchase the ticket to the SiMaTai section, another 40rmb. When we reached tower #20, we stopped for lunch. Hey, it is only noon. We started at 9:40. This means we can finish by 1pm. Wow! Speed!

The Wall literally ended at a river. We need to cross via a suspension bridge. That’s 5rmb toll again. By this time, my legs were pretty weak and I was down to the last half bottle of water. I pointed to the zip-line and told them that’s how we will get down. “Really!” They were scared and excited.

The last part of the wall is the hardest. There are probably less than 50 steps, but your will-power was all depleted. Can I just take a nap on this step, please?

40rmb, again, for the zip-line. They fit you with a harness and told you to “sit down.” All of the sudden you are suspended half-way nowhere, looking down about 150 meters into the water, zipping down without any control of your fate what-so-ever. I felt elated! Wind blowing through my hair and I felt like doing a SuperMan pose. The ride was over way, way too quickly. But the last drop of adrenaline was then spent. Fatigue overcame me. I fell soundly asleep the instant car rolled out the parking lot.

4 months ago, it took me 6 hours. This time, with the young and light, we did it in 3. Not bad, old man.

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