Gas station without pumps

2014 November 16

Good enough for what?

Filed under: Uncategorized — gasstationwithoutpumps @ 11:05
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A blog post by Nick Falkner, Thoughts on the colonising effect of education, ended with the

I had a discussion once with a remote colleague who said that he was worried the graduates of his own institution weren’t his first choice to supervise for PhDs as they weren’t good enough. I wonder whose fault he thought that was?

Nick’s implied message was that it was the duty of the professors to make the undergrads they taught be good enough to go on for PhDs.  But I’m not sure he’s right here.

We do not need huge numbers of new PhDs—some, but not nearly as many as are being graduated from BS programs. Only about 10% of undergrads (or less) should be going on for PhDs, so the majority of graduates from any institution should not be “first choice to supervise for PhDs”. We should be bringing up as PhDs those most likely to be productive researchers and university faculty, and encouraging other students to find productive lives outside of academia (there is a world outside academia, though many professors prefer to ignore it).

If most of the undergrads graduating are top candidates for PhD programs, then perhaps the criteria for PhD candidates are wrong—or the undergraduate program is too small and selective, so that students who would benefit from it are being excluded.

I’m an engineering professor, and in most engineering fields the working degrees are the BS and the MS—the PhD is reserved for cutting-edge research that is not expected to result in products any time soon and for university teaching. I would consider myself a failure as an engineering professor if none of my students went on to become working engineers, but all went into academia.

I expect many of the best students not to be well-suited for PhD degrees—they want to go out into the real world and solve real problems (sometimes to make money, sometimes to save the world, sometimes just for the joy of solving problems).  The best PhD candidates are often not the best engineering students, because a PhD candidate has to be willing to work on an esoteric problem for a really long time with no promise of success, while good engineering often calls for quick prototyping and rapid development, dropping unproductive projects quickly, before they cost too much—not long-term projects that may never pay off.

So, while I certainly want some of my undergrad students to go into academia and to be top choices for PhD programs, I’m happy if most of them are not suited for PhDs, as long as they have acquired an engineer’s problem-solving mindset, enough skills to get them started in a job, and a lifelong habit of picking up new knowledge and skills.

2014 January 18

Engineering Encounters Bridge Design Contest 2014

Filed under: Uncategorized — gasstationwithoutpumps @ 23:23
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Last year’s bridge design did not work well for the 2014 Engineering Encounters Bridge Design Contest (formerly the West Point Bridge Design Contest):

Bridge design costing about $169.9k in the 2013 contest.  Note: I've deliberately distorted the picture to make it difficult to blindly copy the design, as I had problems with middle-school students using my published designs to cheat on their homework.  The truss design I have here can be used as inspiration, but not copied directly.

Bridge design costing about $169.9k in the 2013 contest.

When I tried a similar design in the West Point Bridge Designer 2014, I couldn’t get the cost below about $172k, but a simpler design was cheaper:

$167.3k bridge design for West Point Bridge Designer 2014.

$167.3k bridge design for West Point Bridge Designer 2014.

This design is currently 12 of 41 in the open contest, so clearly one can do better. I don’t expect it to stay high on the leaderboard for long.  It would already be much worse than that on the consolidated board, since the top 10 on the open board only fall in the top 50 on the consolidated one.

I think that the contest would be more interesting to me if they had provided an API for testing bridges.  Then the challenge would be to write bridge optimization software that explored the design space much more thoroughly and tweaked the designs.  It might be possible to do that this year, as the source code is available from sourceforge.  I’m not interested enough in the optimization problem to try to interface to their Java code, but it might be a good way to make a college-level version of the Bridge Designer Contest.

Related articles

2013 September 3

My son’s first PC board

In Towards automatic measurement of conductivity of saline solution, I complained about not being able to use the KL25Z board, because my son was using it.  What he was doing with was building his first prototype for the light gloves project:

Here is his first PC board design, populated and mounted on the Freedom KL25Z board.  The 5cmx5cm board is a bit smaller than the KL25Z board is wide, so it only plugs in on one side (there is a screw acting as a spacer to keep it from being a cantilever).    He has not yet mounted the Bluetooth module.

Here is his first PC board design, populated and mounted on the Freedom KL25Z board. The 5cm×5cm board (the cheap size from Iteadstudio) is a bit smaller than the KL25Z board is wide, so it only plugs in on one side (there is a screw acting as a spacer to keep it from being a cantilever). He has not yet mounted the Bluetooth module.

The prototype board has many differences from the final design: no battery, no battery charger, no buck/boost regulator, no flash memory, no processor, screw terminals instead of jacks—even the LED driver chip is different, since the chip he plans to use is only available as a surface-mount device. But there is enough of the design here to start demoing and writing code.  They are hoping to keep the final board below 5cm×5cm, so as to get low PC board prices even in very small production runs.  That will mean all surface-mount parts, so I think I’ll have to get a hot-air rework tool so that they can assemble a prototype—I’ve been thinking that I might want one for myself to play with surface mount designs, so this isn’t really a hardship.

My son still owes me some money for buying him the PC board run, the screw terminals, the Bluetooth module and some heat-shrink tubing. It is a bit annoying that he isn’t old enough to get his own Visa card, so that he can do his shopping without me as an intermediary. (We’re not talking big bucks here—we’ve spent more on pizza for him when they work through dinner than they’ve spent on all parts combined.)

I’m pleased that he got his first PC board working on the first attempt—he did the design entirely on his own, though he did ask my advice about things like via sizes and how fat to make the wires. Since there can be moderately high currents for the LED driver, I recommended that he make the ground and power lines as fat as he could, and he decided to do a flood for each. The board looks quite nice:

The top view of the board with the screw terminal to be mounted on the top and sides, the header on the lower left, and the Bluetooth module on lower right.  The hole near the top right is for the screw that acts as a spacer.

The top view of the board with the screw terminal to be mounted on the top and sides, the header on the lower left, and the Bluetooth module on lower right. The hole near the top right is for the screw that acts as a spacer.

stationary-glove

This is what the glove looks like with the five RGB LEDs lit up (I understand that the final design will have more LEDs—but the through-hole driver chip has limited pinout). They don’t have the user interface written yet, so the lights were set up by a quick-and-dirty Python script talking to the KL25Z board over a USB cable (which is also supplying power).

waterfall-glove

They have not implemented programmable flashing yet, but the pulse-width modulation (PWM) frequency is set very low here (much lower than what they intend to use in the final design), so that one gets a stroboscopic effect even with steady light settings, just from the PWM. That’s not my son in the picture, but the high-school student who started the project—my son has done most of the electronics and programming, but did not originate the idea.

The two teens spent a big chunk of the day wiring up the LEDs and writing a small test program, as they want to demo the glove tomorrow for the back-to-school event. It may also be an enticement for teens to join an Arduino/microcontroller club—look at the cool stuff you can learn to make!

arc-glove

Another view of the prototype light glove in action.

Once they got the demo working, they invited over a third member of the team to do some brainstorming about what else needs to be done (and how they’ll do it). It looks like they’ll be talking half the night.

Since it is clear that my son will be spending a lot of time on this engineering project this year, we decided to make it part of his official school work.  In addition to the engineering design work, he’ll also do some a paper for his econ course (on pricing the components and manufacturing, and setting a retail price for the gloves), and papers for a tech writing course.

His first tech writing assignment is to write up a description of the color space he decided to use for representation of colors in the program, and why he chose that color space out of the dozens available.  He spent a week thinking about color spaces anyway, before settling on a commonly chosen one—so writing up that reasoning for the other members of his team will be a good writing exercise.

2013 February 10

National Engineers’ Week

Filed under: Uncategorized — gasstationwithoutpumps @ 10:18
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Next week, 2013 Feb 17–23, is National Engineers’ Week.  (My apologies to the organizers, but I refuse to spell it without an apostrophe as they do.)

Thursday (2013 Feb 21) is Introduce a Girl to Engineering Day.

I’m not aware of anything that the Jack Baskin School of Engineering at UCSC is doing, but I’m just a faculty member, and we’re always the last to be told anything (and then generally in the form of “the deadline is tomorrow, drop everything and do it now!”). National Engineers’ Week seems to be organized mainly by international tech companies (heavy on the energy and transportation industries), and they’ve apparently not done much for involving universities in the program.

I don’t have anything planned for National Engineers’ Week myself, because I only found out about it a few minutes ago.

To be fair, I heard of it two years ago also and had similar grumbles about the lack of visibility.

2013 February 9

Becoming engineers

Filed under: Circuits course — gasstationwithoutpumps @ 20:23
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In The Art of Becoming Yourself, Chad Hanson discussed the hard-to-measure cultural value of a university education.  I was particularly struck by his statement:

Educators spend a good deal of energy testing critical-thinking ability and, frankly, are frustrated with the results. One reason we have difficulty producing critical thinking is that we separate thinking from thinkers. We treat critical thinking as if it were a free-floating ability when, in fact, it is a function of oneself or one’s identity. Critical thinking is a way of positioning oneself toward a problem. For critical thinking to take place, students must first come to think of themselves as people who are willing to take a critical stance in relation to an issue.

This resonated with me because I’m trying to teach the bioengineering students in my circuits courses to “think like engineers“, but I had not thought of the problem in quite the way that Dr. Hanson put it.  My goal is not to have students “take a critical stance”, but to be able to solve problems that they have never seen before.

I’m really trying to make the students see themselves as engineers, rather than as students—to have them think of themselves as people who can look at a problem and decompose it into solvable subproblems, as people who are willing to explore possibilities without knowing that there is a correct answer in the back of the book, and as people who can design solutions.

I want them to think “let me look on the data sheet” and “let me measure that and see”, rather than asking “is this right?”

I want them to look at a breadboard that isn’t working, and start by checking each wire to see if it is consistent with the schematic, rather than just calling the TA or me over for help  (80% of the debugging I’ve done for students is pointing out that their wiring doesn’t match their schematic).

I want them to draw their own schematics, checking to make sure they know what each wire and component is for, not just copying and pasting someone else’s. I want them to check their schematics to be sure they haven’t shorted power and ground, and that every input and output is appropriately wired, not left dangling.

I want them to do quick sanity checks on every calculation or design decision, asking “is that consistent with what we know already?” and “are the units right?”

They’re all capable of doing these things, when told to, but they have not yet changed themselves to the point where they tell themselves these things without being nudged.

If they forget in a year how to compute the corner frequency of an RC filter, I’ll be only mildly disappointed—if they need it, they can look it up or rederive it in a few minutes.  But if they forget that they can rederive  formulas from a few simple principles, rather than having to memorize or look up solutions to every possible problem, I will have failed.  If they forget or don’t learn how to decompose problems into subproblems, or how to write a design report that can be understood by people who’ve not read any prior problem statement, then I will have failed.  If they forget to look at datasheets or to do consistency checks on their own work and that of their colleagues, I will have failed.

Dr. Hanson quotes Alexander Astin:

In his classic What Matters in College?, he concludes, “The student’s peer group is the single most potent source of influence on growth and development during the undergraduate years.” As educators, we assume that students enroll in our classes for the sake of the learning outcomes listed on our syllabi. The truth is that learning outcomes are actually a small part of the endeavor. The postsecondary ritual is a large and life-changing experience.

That suggests to me that it will take the students helping each other to make the change to thinking like engineers.  I can give them exercises and labs in which engineering thinking is valuable, and I can give them questions to ask themselves, but it may take the students asking each other these questions for the change in their ways of thinking to become part of who they are.

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