Simulink World Tour

Last week, I had an opportunity to participate in the Simulink World Tour, hosted by Mathworks. I was attracted by the agenda of showing all different applications of Simulink. Personally, I have been fascinated by the easy and intuitive way to build a system and solve for the solution. That’s the way mathematic should be – to help people visualize and construct the problem. The actual mechanics of solving for the mathematic solutions is less than interesting, at least for me.

In the morning session, they showed off a bunch of stateflow, design verifiers modules, VHDL code generation, which are good for logic verification. They also added PolySpace to check for code correctness.

What stood out for me are the embedded Matlab C code, which are great to speed up execution speed once it’s compiled. The image processing demo in the video surveillance application was quite interesting. I didn’t know the execution speed could be fast enough to do that. They also showed a hybrid car’s electro-mechanical system built with simulink and how the gas mileage fluctuated when the gas peddle is floored. This demonstrated how the system modules can be built and simulated when the interface behavior are properly modeled.

During the buffet lunch, I observed that most of the participants came from the defense industry. They probably deal with system simulations a lot due to the analog/RF nature and the interactions between electrical and mechanical systems. I can see how powerful simulink can be if put to good use. I would like to play with simulink but haven’t seen a good fit for my line of work, where things tend to be mostly digital. The analog-digital interface has been largely shielded by the chipsets. I’m still looking…

Fixing Water puddle (standing water) in the Dishwasher

[Revised on 10/10/12 for an improved/easier way to fix the problem]

Dishwasher is notorious for having water puddle or accumulation on the bottom. My dishwasher would develop this problem every 6 months and it got very annoying because the dishes don’t get cleaned properly. The problem usually doesn’t go away on its down. The dishwasher expert would tell you that it’s pretty normal to have some water accumulated on the bottom. And if it kept getting more severe, then you may need to fix the motor or the disposal system (yes, there is a mini garbage disposal system in the dishwasher to grind out the solid food) within the dishwasher. Well, that’s a very expensive proposition. Based on my experience, there is an easier way. I suggest you try my method first before calling the dishwasher repairman if you want to save some money.

In my experience, the problems lied in the airgap (the waste water hose from the dishwasher gets routed to the airgap and then routed to the garbage disposal in most cases) or lack of cross-section area in the airgap. There was usually some big food chunks that don’t get ground out small enough to pass through the airgap. I have seen large nuts, vegetable stems, chicken bones, and etc.

To fix this problem, do the following:
1. Slide out the chrome top of the air gap.
2. Remove the top of the air gap by pinching the two tabs on the side. (Some fo the air gaps have the screw-on top, then you would just unscrew the top) You may need to use two blade-type screw drivers to pinch from the top and then lift up the top. See picture below:
Air Gap
3. Place a large glass over the exposed air gap and direct the opening
back to the sink. The dirty water will come out here.
4. Turn on the dishwasher. Almost immediately, the dirty water will be jetted out. Make sure you hold the glass steady or you’ll have an “old faithful” coming out of the kitchen.
5. After the dirty water is completely out, turn off the dish washer and place the air gap cap and slide the chrome top back on. The clog should be cleared.

If it doesn’t work, you can follow my old methods below or watch
the Youtub video here for a more thorough cleaning.

1. Remove airgap assembly from the kitchen sink.
2. Remove the hoses (both sides) from the airgap. Check for obstruction in the airgap. Replace the airgap (~$10) if it’s worn out. It’s not worthwhile to fix a broken airgap. Clear the obstruction from the airgap. I have seen a broken tip of a chopstick, a chicken wish bone, and etc. in the airgap before. If you are confident that this is your problem, you may skip the rest of the steps and jump to the last step.
3. Put a big empty bucket (~5 gallons) under the hose.
4. Turn on the dishwasher. Usually the first step for the dishwasher is to clear out the water within the dishwasher. You may see the waste water coming out right away. If not, then there is really something wrong with the dishwasher – call the repairman. Otherwise, keep having the waste water flushed out of the dishwasher until you’re certain that all of the debris has been flushed out. You may need to do this several times to get it out.
5. Re-attach the hose to the airgap and re-attach the assembly back to the kitchen sink.

You may need to repeat the above steps a couple of times to get to the culprit. If all fail, call the dishwasher repairman. Hope this helps.

The End of My Composting Experiment

Last Wednesday, 9/26/07, I dumped my entire collection (2) of my compost bins into the garbage bin, ending my three-month experiment with composting. I bid farewell and bon voyage to my red worm friends. They’ll probably have a better time with other people’s garbage in the garbage dump. This was done after much urge and complaint from my wife about the stenches from the bins. She’s more concerned with the Qi around the house than being eco-responsible.

Motivated by the good feeling of eco-responsibility and after seeing lots of grass and green stuff being dumped into the yard disposal bins by my gardener, I thought I might do the earth some good by composting and reducing the waste going into the dump. The constant bombardment from the Sunnyvale city’s flier on free composting class also helps to start the cause. I didn’t have the time to attend the composting class, so I borrowed a few books from the library on composting and started reading about it.

It seemed easy enough: mixing brown (dry stuff like shredded newspaper, or dry leaves) with green (wet stuff like grass, vegetable trimming, left over vegi food, and etc.) and just let them sit for a couple of months while keeping the chemical reaction going by adding water to the pile (like a sponge with the water half squeezed out). But it was too easy besides I wanted to speed up the process, so I added some red worms to the pile. This automatically qualified me as the “vermicomposter,” which is the next level up in the composting hierarchy. And it’s probably more fun because there were something live feeding on the garbage, not just bacteria that you couldn’t see. The worms were quite expensive: $20 for 500 worms, and I needed 2x that for a bin. I immediately figured the money for the composting business is inn the “worms.” Now if I could grow/farm the worms …. 🙂

So I checked the worms from time to time. Some of them tried to escape from the holes and died on the concrete floor, dried up like a bacon. The remaining ones continued to grow substantially. They were supposed to propagate exponentially within weeks but I didn’t see that probably because my compost bins were “fertile” enough.

In the end, I came way with the following conclusions:
1. Composting is not for the faint of heart, it takes dedication to monitor the moisture level and keep the compost aerated – not a simple task for just a hobbyist.
2. We produce garbage much faster than the worms and the nature can absorb and breakdown normally due to the long breakdown time. Unless I have a composting factory in the backyard, which is probably doable in a suburban area but not in a city, I would never be able to make a dent on reducing the waste.
3. Red worms are a fascinating species. They play their designated role well but they can do better or work faster. Bioengineering of red worms might do some good in reducing/consuming the world’s ever increasing garbage contents.
4. Adding blending to the organic/vegetable trimming waste, as suggested by the experts on the net, might help to increase the breakdown time by the worms and bacteria, thus less stench. This was a variable I haven’t tried yet.

This was a fun experiment and experience. If I have a bigger house with a bigger backyard, I might try again sometime later. Or, how about making a “worm farm” on a glass container? They might make a good toy for a kid …

Intel Developer Forum (IDF) and Moore

On Tuesday, 9/18/07, I attended Intel Developer Forum held at the large Moscone Center West in the beautiful San Francisco. IDF is celebrating its 10-year anniversary this year and yet I have never attended one before, perhaps due to my association with Sun. Intel is a relatively new partner to Sun and we’re ramping up the learning curve on Intel’s offerings so we can design server products around it.

I came away very impressed with Intel’s speed in execution. Looks like they have all the ducks lined up and firing on all cylinders: Penryn, Nehalem, Tolapai, and etc. The attendance was very good – around a thousand or so. The topics that stood out for me:

1. All the 3-week-old wafers that are showing off Nehalem, Tolapai, and etc. Looks like they’re working just fine. Excellent execution, Intel. Being paranoid and having a good competitor like AMD really helps to spear things along. 🙂

2. USB3: 10x the speed of USB2. It has optical and copper phy layer. This could potentially put some of the PCEe devices out of business due to the parity in performance. Of course, we may see an explosion of I/O devices that normally resides within the box. I can just picture HDTV, HD camera, high-performance storage array, and etc.

3. Mobility: WiMAX and etc. We may well be cutting out all the cables soon on PC’s.

4. I didn’t get the chance to see the show cases. I heard lots of good product offerings though.

The highlight of the day is the appearance of Gordon Moore, the originator of “Moore’s Law.” By his own account, Moore’s Law may soon hit a wall in 10 or 15 years when we may hit the physical limits of material properties. When asked about making tough decisions, he said, “Tough decisions are normally very close. You may as well toss a coin.” Dr. Moore suggested that life science may be the way to go for today’s engineers. Being in a new industry has its reward as in the in case of Gordon Moore himself. He projects that computer still needs to be able to interact with human as the next wave of computer innovation.

I felt a sense of excitement as in the early days of the computer shows. Intel is leading the effort to re-shape the computer industry. I think I’ll go back again next year.

Sendmail relay woe on VPN

Today I ran into the a weird sendmail problem: I kept getting “relay denied” message when I tried to send emails out. I tried another mail host without any problem. I even used another client machine to send mail from my original mail host without any problem. I checked the /var/log/syslog and found something like the below:

Sep 20 11:36:42 tsai86 sendmail[7272]: [ID 801593 mail.notice] l8KIafBt007272: ruleset=check_rcpt, arg1=, relay=vpn-129-150-36-151.Central.Sun.COM [129.150.36.151], reject=550 5.7.1 … Relaying denied

Checking against earlier successful email log like the below, I noticed the difference being “relay = vpn-129-150-36-151.Central.Sun.COM [129.150.36.151]” vs. “relay=local”.

Sep 20 10:55:57 tsai86 sendmail[7160]: [ID 801593 mail.info] l8KHtsjO007159: to=, delay=00:00:01, xdelay=00:00:01, mailer=local, pri=34029, relay=local, dsn=2.0.0, stat=Sent

Cutting to the chase, I logged out of the VPN session and re-logged in the VPN. Voila! The send mail problem went away. How strange! The only explanation I have is that the VPN somehow got confused thinking I’m on a different domain or the IP address got interpreted to be on a different domain. A little hiccup on the network creates a slew of problems. I was told I wasn’t the only one having the problem. Strange indeed.

Book Review: “The Assault on Reason” by Al Gore

Al Gore, following his success of “An Inconvenient Truth,” fired another warning shot to the American people that our way of democracy has fallen far away from the original intents of our Founders. There are lots of things that are going wrong that we may not be aware of. If we don’t do something about it, it may be too late for this generation and our future generations. Professor Gore kept going back to the American and foreign history, citing numerous precedences and evidences to reinforce his arguments.

My main take-aways:
1. Attack on TV Journalism. TV’s are to sell advertising; reasons are set aside. Political candidates can now “manufacture consents” by promoting his/her ideas on TV and/or influence what’s covered on TV, in other words, manipulating journalism like by having fake White House correspondents. Honestly, I don’t watch that much TV but I can imagine if people do spend 4+ hrs a day on the average, it can be a powerful influence. Of course, Al Gore did offer Internet as away to counter the force, provided we can keep the Internet from being tainted by false assertions.

2. Bush administration is “bad” and the main culprit in the assault on reason. He even equated George W. Bush to Nixon, having little tolerance for health/open debates and focus on concentrating power on the executive branch. Bush fabricated the evidences of Saddam Husein’s buying nuclear materials to make Nuclear bomb – weapons of massive destruction. The Bush administration used the Iraq war to benefit the oil industry lobbyists, while damaging the principles of this country in front of the international community and jeopardizing our military personnels by going against the Geneva Convention in the treatment of the “unlawful combatants.” He even cited a historical lesson of how Roman lost their democracy after Caesar marched in to Rome, against the Roman Laws made by the Senate.

3. This is a good civic class on how US democracy was born and the considerations given by the founders to preserve the check and balance. He emphasized that we are a country ruled by laws not people. The lack of written communication, due to TV, may serve as catalyst to deviate from the laws, fundamentally given in and interpreted from written words.

4. Democracy is fragile. Too much power concentration on the executive branch is a hazard. We could be in a long Iraq war and war against terrorism that may tilt the power to the executive branch for a very long time, jeopardizing the check and balance from the legislature and the justice branches. Citing Benjamin Franklin’s words when asked about the United States being a republic or an empire. He replied, ” a republic, if we can keep it.”

5. Legislature needs to have good debates. Most of the critical legislations are not being debated because senators/representatives are mostly absent – too busy raising funds for their own elections. He proposed to have TV coverage on debates so we can all make sure we understands all the pros and cons of each legislation piece. This is a good idea except no TV producers of the right mind would produce them due to lack of advertising.

6. Environment protection. Not only Bush administration went to the Iraq war for the wrong reason, Bush immediately dropped all the environmental protection clauses for the benefits of his political supporter. He mentioned a few things that’s already covered in his “an inconvenient truth” video, like the weather pattern change resulting in Katrina and potentially more refugees from the rise of sea level. Do we the courage to do the sensible/reasonable things? The era of consequences is upon us.

This book can be cut shorter by not taking on the Bush administration solely and by highlighting all the great things the Clinton/Gore administration has done. It’s a bit self glorifying – lose some credibility there. Also, Gore went to a lot of details about how the brains are vulnerable to the TV’s brain washing – as least he didn’t claim that he invented it like he did with Internet. 🙂

Overall, it’s not a bad book. I learned a few civic lessons about America and why our way of life may be very fragile if we don’t pay attention to protect it from the tyranny of the concentrated power in one particular branch because our lack of reasons. Perhaps, someday this book can be used to teach civics in schools. Hopefully, it’s not something we regretted haven’t heeded.

assault-on-reason.jpg

Book Review: “Teacher Man” by Frank McCourt

This is the 3rd book by Frank McCourt following his 1st successful story, Angela’s Ashes. I have yet to read that book. Frank McCourt’s strong Irish accent was hard to understand in the beginning of the audio book but I eventually got used to it. In this book, he talks about his 30-year career as a high-school teacher in New York’s public school, plus his marriage failure and his failed attempt to obtain his PhD degree. There is a lot of stories about his battles against 5 classes of 35 students each day and how he needs to be on top of his game in order to survive. In essence, this book is about an underdog’s personal failings, survival, and success story. The stories are at times sad, shocking, touching, but mostly funny.

There is this story about his taking the teacher oral exam and when he was asked how he would reinforce a creative writing lesson. His answered, “write a suicide notes,” almost got him kicked out of the exam room. But clearly there was someone that saw through his talents and his unorthodox teaching style. He passed the exam, of course.

The dynamics he has in his classroom varies quite a bit. Early in the book, he talked of how he picked up and ate a sandwich that one of his students threw at him. In a way, he puts himself in the same level as the students to gain their trust and that created quite a stir in the school. Often times, he was distracted by students’ constant requests for more stories from him and he often obliged. This created conflicts between his teaching style and what the school expected of him. As a result, he went from one school to the next early in his career.

His teaching style reminded me so much of my high-school “Health Education” teacher in Taiwan. As a student, I always looked forward to listening her stories and still remembered a lot of her stories to this day because she delivered the teaching with stories wrapped around it that made them meaningful to me. Story telling is a skill that is often under-rated.

One of his unorthodox teaching assignments includes writing excuse notes for the students themselves, famous characters like Hitler. This assignment absolutely captivated the students and made it meaningful for them because it’s something they’ll need for the rest of their lives. The other interesting class assignment involves reciting and signing recipes from cook books. Wow, I can simply picture the smiles in the kids’ faces.

McCourt is more interested in how people feel about a poetry or any piece of writing. It’s not about saying the right answers so you can go to college and move ahead. It’s more about appreciating the impact the authors’ writings have on the readers. After all, writing is about communicating with impact.

In several of the open school nights with parents, he spoke of parents battling each other and took up on him. But this story really touched me as a parent. He claimed that throughout his career, there was only one time a mother asked him whether her child was enjoying himself and that was only question she had for him. As a parent, we often don’t think of school as a place of enlightening our children so they can be a happy person throughout his/her life. Instead, we think of it more of a transition place where our children need to take knowledge from so he/she can eventually be happy making lots of money later in life.

He told of this student, a Korean kid with overbearing parents who worked day and night at a flower shop just to give him the best education. He chose Stanford University over Harvard and MIT just to stay away from his parents. When he was asked by his English teacher at Stanford about his favorite poem, he said “Papa’s Waltz” and he broke down and cried and cried. This was the poem they discussed in his high school class with McCourt:

The whiskey on your breath
Could make a small boy dizzy;
But I hung on like death:
Such waltzing was not easy.

We romped until the pans
Slid from the kitchen shelf;
My mother’s countenance
Could not unfrown itself.

The hand that held my wrist
Was battered on one knuckle;
At every step you missed
My right ear scraped a buckle.

You beat time on my head
With a palm caked hard by dirt,
Then waltzed me off to bed
Still clinging to your shirt.

We often neglect how much influence our teachers have on our lives and claim all the credits as our own in our successes. This book drives home the impact our teachers have on our lives and the sacrifices they make. To all the teachers in my life, I thank you from the bottom of my heart.

teacher-man.jpg

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