De Morgan's Laws in Action

Augustus De Morgan, originally uploaded by Mike Lynch.

Logic: It's a beautiful thing. It's not everyday, however, that I get to implement it so explicitly as I did today.

One of the hallmarks of mathematical logic are some rules set out by Augustus De Morgan called, appropriately, De Morgan's Laws. They go something like this: Take two (or more) statements A and B. These can be things like "The sky is blue" and "We are on Earth." These statements have complements, namely, "The sky is not blue" and "We are not on Earth."

De Morgan gives an equivalence between the relation of these statements' complements and the complement of the relation of these statements. In (better) English, we could say that the complement of A and B is the complement of A or the complement of B. So, in our example, De Morgan tells us that the complement of "The sky is blue AND we are on Earth" is the same thing as saying "The sky is not blue OR we are not on Earth." Confused? Try out the formal statements for a bit of clarification:

where we read "c" as complement,

and

Why would this ever arise in practice, you might ask? In fact, just today I wanted to add a stopping condition to a WHILE loop I had in a program. A WHILE loop runs (loops) for as long as a given statement is true. My loop ran for as long as the variable called FLAG was true. Essentially, I wanted to cheat a little and add a different stopping criterion that would bounce out of the loop if a different variable hadn't been changing for a while.

So in my head, the loop should run while FLAG was true, and it should stop when COUNTER was bigger than 20 and W(COUNTER)==W(COUNTER-20). But, just my luck, you can't really tell a WHILE loop when not to run, you have to tell it when it has to run. But guess, what? These conditions are complements! Enter De Morgan.

My situation was that I want to stop the loop when

is true. Which means that I want to NOT stop (i.e. run) when

is true.

Bonus! We get to use both flavors of De Morgan. First apply the first equation from up top, then apply the second to the B parentheses. After all is said and complemented, I want to run my WHILE loop while FLAG is true AND (COUNTER is less than 20 OR W(COUNTER)~=W(COUNTER-20)). Cool huh?

Stay Logical.

Smarter Grids

Low Mill, Caton, Near Lancaster, Lancashire, UK, originally uploaded by Ministry.

[For those looking for "How to Peak Around a Corner," give me a couple more days. It's a bit harder than I first thought.]

I literally just got out of a seminar given by Marija Ilic, of Carnegie Mellon, on her work and prognostications for making the delivery of electric power more efficient. I was expecting the typical drab droning that usually confronts me from invited speakers, but I was able to pull several salient and cogent points out of her talk. This is a fairly extemporaneous post, so please forgive my stream-of-consciousness style.

Utility companies, in general, try to provide uninterrupted service at minimal cost to their subscribers. We could go on and on about the scruples of utility companies and their guaranteed monopolies, but that is not really very productive at this point, so let us take their cost-minimization desires as a given. While "minimal cost to subscribers" is a very soft term, I never realized how hard the uninterrupted service constraint really was. Imagine this scenario: Town X has a daily power consumption of no more than 90 MW for 350 days a year. Given this information, constructing a 100 MW power plant to supply Town X seems like a good idea. However, for 15 days per year, Town X demands 120 MW (due to heat waves, cold snaps, etc.). If the utility company really had only constructed a 100 MW power plant, all of the directors would be fired after the first year because they couldn't supply the town sufficiently for 4% of the year. So instead, the utility has to lay out the cash to build more power generation capacity that just sits around for up to 350 days a year.

As Prof. Ilic stated, "cost management is all about the spikes." She was referring to the spikes---hourly, daily, and yearly---in demand that utility companies see. If it weren't for the spikes in demand, the total demand would have far less variance, and less superfluous generation capacity would be necessary.

What can we do about these spikes? This is where the system intelligence comes into play. Prof. Ilic claims that currently, most utility companies have extensive records to estimate their long-term average demand, but they use only something like the past 15 minutes of data to predict upcoming surges. I would really like to see a "look-ahead" filter (or model-predictive controller, as Prof. Ilic calls it) on the power companies' demand estimates. This information should then obviously be distributed out to the consumers, who then are incentivised to decrease demand when faced with surging costs.

Obviously this incentive scheme can only be implemented with some form of "smart meter" at the consumer side. It really baffles me why these haven't gone past pilot programs across America. The basic functionality of a smart meter is that it records the power drawn by a consumer, and logs this information over time. More dynamic implementations could go so far as to incorporate an automatic controller. This would be a household appliance (there's an app for that!) that lets the user list and prioritize power-hungry processes as well as input a desired maximum cost of electricity each day. The meter/controller would then use the predicted power costs to schedule the user's processes to run as time---and money---allow.

Smart Meter, originally uploaded by tmvissers.

The funny thing is: This "scheduling" of "processes" already happens in every office and nearly every home in the country. Computers and servers operate on the very principle that some processes have higher priorities than others, and that they will all (hopefully) get done in due time. Except that computers decide between processes thousands of times every second. Should it really be that hard to decide to run your laundry dryer at 1:00 AM and your dishwasher at 3:00 AM?

This pseudo-rant so far has only touched on the "one-way" current model of the power grid. The sexiest topic in smart grid research is how to (best) incorporate distributed power generators. On the one hand, the concept is quite simple: Whereas before a utility user could be viewed solely as a power sink, now there is the possibility of seeing a negative sink (commonly referred to as a source). However, as Prof. Ilic is quick to explain, things are not quite so simple.

All electric power these days travels into our homes on endless sine waves of current. In the US, if you were to stand at one point on the transmission wire, the peaks of these waves would pass you 60 times every second. This standard has allowed for the universal (well...almost) wall plug that all your household devices use. Correspondingly, the power companies transmit and transform the power so that this is exactly what you get at the "tap." When people start generating their own power, there is currently (haha...get it?) no way of knowing that the phase of the user-generated signal will match the phase of the utility-generated one. This phase-matching problem is fairly serious and expensive to control.

The alternative, it has been postulated, is to discourage end users to feed back into the grid. Rather, users should endeavor to store as much of their locally generated power as possible. Now people are thinking inter-disciplinary. Now if you have a plug-in hybrid vehicle, you instantly have a massive battery in which to store your excess power. It's like a two-for-one! The problem is that without dynamic smart meters, everyone comes home from work and at 6:00 PM, plugs in their hybrid and create one of those damned spikes. Now you see how all of these problems are interconnected.

I'll wrap things up with a little utopian vision. My dream house will have several acres of woodland (and be under an hour on public transportation to a major airport) on which I can erect a wind turbine or two. These will provide power to my house as allocated by my self-designed power controller. On windy days, I'll have so much electricity that I'll be able to pump water out of a little stream into a tank uphill from my house. Then, when I need hot water for my bath, I'll suck it out of this tank, through a parabolic reflector and then through a generator, into my tub and use the electricity to run my reading light. Too easy.

Stay smart,

Clay

How to Peek Around a Corner - Part 1

around the corner,, originally uploaded by ~Faiz.

Occasionally in my reading, I come across a particularly well-posed question that I feel is not only accessible to "lay" readers but also interesting to them. The problem of how to best look (or "peek") around a corner is just one of these questions.

As a warning, I will pose the question in this post and then solicit ideas and answers from the readers. Then next week I'll post a solution and hopefully an example.



First, the setting: You are Bruce Willis in Die Hard. You are pursuing and being pursued by bloodthirsty terrorists in a strange office building. You find yourself walking in a smoky room with your hand against a wall in order to not get lost. All of a sudden, you notice that your wall comes to an end exactly one meter in front of you. You pause and analyze how to best approach this corner in the wall in order to be able to see down the adjoining wall.





If you knew the angle that the adjoining wall intersected your wall (and this angle was acute), the quickest path would be one that departed the wall you were following at an angle of
90-\phi and traveled in a straight line for \sin\phi meters. This would take you directly to the "extension" of the line of the adjoining wall and would afford you an unobstructed view down that wall. Conversely, if the angle is obtuse, it would be quickest to just go directly along the wall to the corner. This concept is illustrated in the figure below (courtesy R. Dorrigiv and A. Lopez-Ortiz):




The tension between these two approaches (curl out into the room versus proceed directly to the corner) represent the crux of this path-planning problem.

Let me finally pose the question: Starting from one unit "south" of a corner with unknown acute angle (between 0 and 90 degrees, inclusive), what is the best approach path, and what does "best" mean to you?

A solution---and my take on it---coming soon.

2010 ARCS-Honolulu Kresser Award in Engineering

Every year, the Honolulu chapter of the ARCS Foundation (Achievement Rewards for College Scientists) presents scholarships to a select number of graduate students working on research in the various sciences at UH Manoa.

This year, there were 12 awards given to students ranging from the physical and natural sciences to health sciences and engineering. I was one of two students (both from Electrical Engineering) to receive an award from the College of Engineering.

In exchange for the award, the ARCS Foundation asks the students to prepare short semi-technical talks and posters to share their research with the donors and coordinators. I took this as a great opportunity to hone my (slightly rusty) public speaking skills, and prepared the slideshow below to augment my ten minute talk.



(edit: It looks like the video player has cut off the title slide. You're not missing much, but the whole thing is available via the links below)
The slides and poster are both also available as PDF's.

In addition to practicing my speaking skills, the presentation session was enjoyable because it shed some light on the interesting research being done by 11 other bright scientists around the campus. Some particularly interesting work is being done by Jim Baker (EE) in compact high-frequency radio antenna design, Brendan Bowler (Astro) in the search for extra-solar planets, and Tiffany Anderson (Oceanography) in shoreline erosion due to storms.

New Site, v2.0!

That's right, after about a one month hiatus, my website for all things academic is back in action. I really would appreciate any comments and criticism you have about it. I am an utter n00b at most of this.

Wondering what motivated the revamp? To be honest, I was quite happy with the old version that I built with iWeb. It turns out that iWeb was not as happy with it. After adding a blog entry in the native iWeb interface, the application crashed and would continue to do so after any further modifications to the blog pages. Since I don't really foresee this type of website changing very often (aside from the blog section), it didn't make much sense to me to continue along that path.

I made the effort of actually taking my computer in to an Apple store to see if their employees (I find it pretentious to refer to them as geniuses) could offer any suggestions. The technical support rep was congenial and sympathetic to my plight, but in the end, entirely unhelpful in resolving issues with a corrupted iWeb site.

At this time, I sought the advice of the foremost computer guru I know: Ben, one of my best friends for over 10 years now. His advice on which GUI-based website builder to use: None. Every site he's written has come from the vast white wasteland of a plain text editor (he recommended gedit, by the way). I can't really blame him; nothing teaches you how something works like building it from the ground up.

So, I pulled all of the site's files down from the University of Hawaii server and set out to write my second website (the first being the v0.0 of this same website, but its layout was worthy of Geocities, and I don't really like to talk about it).

In this process, I've become much more familiar with HTML elements (and the fact that there are only about 20 or so relevant tags), cascading style sheets (CSS) to format the content, and browser versus server functionality. None of these would have come out of simply recopying the iWeb site. Throughout the process, the website HTML Dog proved an invaluable resource for me to constantly look up (and re-look up) the proper terminology for the effect I wanted to create.

As of today, the site is up and fully operational. Features I am particularly fond of are the Post-it "contact" info, and the embedding of this blog in the "News" page. If you'd like, go ahead and unsubscribe from the old blog's feed and add this one. Also, yay for comments.

Stay < marked up />
Clay

What a Meal!

Spam Pizza, originally uploaded by kcmckell.

Originally published Saturday, April 17, 2010.

Every so often, I enjoy a meal that truly moves me. Sometimes it is the result of hours of my own sweat equity in the kitchen, but more often I am the benefactor of someone else’s culinary creations. This was the case this weekend when Serena and I dined at Frasca in Boulder, CO.

I feel compelled to share my thoughts on the dinner dish by dish. I'm saddened that these words can never truly express the oral jubilee that was this meal.

Antipasti

• Columbia River King Salmon “Crudo” with beets, horseradish and olive oil
  

In all honesty, this has to be my favorite dish of the night. I know it’s silly to start a review/rave with the apex, but hey, I’m just writing chronologically here. It’s their fault for making the first dish so freaking good! Crudo is Italian for raw; so I guess this makes it my favorite sashimi dish as well. The fresh horseradish is a paste rubbed on the paper-thin cuts of raw pink fish flesh. The olive oil path was an excellent counterpoint to the horseradish tang.

• Treviso and Honeycrisp Apple Salad with sopressata, asiago and apple “purea”
  

This was a good starter that we ordered primarily in anticipation of having several heavier courses to follow. It did not disappoint. The greens were fresh, and appropriately sprinkled with matchstick-sized slices of apple and sopressata (a salami-prosciutto hybrid of sorts).

Wine

• Domaine Wachau Gruner Veltliner Smaragd “Achleiten” 2005 from Wachau, Austria
  

Our first venture with a sommelier was certainly a success. He listened patiently to what we had ordered, and then proceeded to rattle off a few wines followed by strings of descriptives that I had never heard applied to things that could be ingested. In the end, Serena keyed in on "hints of pear," and we were on our way to Austria. Upon further review, this year received a 92 rating and was not nearly as sweet as a Riesling, which would have taken over the meal.

Primi

• Four Story Hill Farm Rabbit “Agnolotti” with marsala “brodo” and pecorino grand cru
  

I am a sucker for light Italian pasta sauces (brodo = broth). The simplicity of this dish was it's selling point. There wasn't much to interfere with the delicate and distinctively not gamey rabbit.

• Hand-cut “Pasta alla Chitarra” with Colorado lamb meatballs, baby artichokes and roasted red peppers
  

Another light pasta dish, the noodles here were fantastic. Alla chitarra simply means that the long, thin noodles were cut on a device similar to a guitar. Get it? Serena particularly complimented the roasted red bell peppers. She should know, the ones she makes at home are quite divine.

Secondi

• Maine Diver Scallops with borlotti beans, chard and house-made pork sausage
  

I really through common sense to the wind here and went with a shellfish dish in a city about 850 miles from the nearest living scallop. My "adventurousness" was rewarded however! The scallops were done very well and the crispness of the chard and the grit of the borlotti complemented their texture well. There could have been a couple more pieces of sausage, but as it was, the scallops remained the focal point of the dish.

• Poached Pacific Halibut with Chanterelle mushrooms, fennel and broccolini
  

I might venture that this was the blandest dish of the night. To me, it could have been spiced a bit more, but then again, I often like to get punched in the tongue. Perhaps I need a bit more patience with white fish of this variety.

Dolci

• Chocolate “Torta”
  

Silly me. I was expecting a molten chocolate torte. It seems that it was lost in translation that torta actually means cake. And cake I got. Delicious light chocolate cake with a surprise dollop of vanilla (with a hint of almond?) gelato with bits of praline. Scrumptious.

• Formaggio assortment
  

Cheese for dessert? Oh yes she did! Not surprisingly, I didn't get to taste this dish much because any of my advances were met with stabbing fork motions from across the table. It sure looked good. The jam that I got a taste of was quite good.

There you have it. A dish-by-dish breakdown of a meal that lands itself firmly in the top five all-time. Frasca, you undoubtedly get my glowing recommendation.

For the interested reader, the restaurant opens reservations up two months ahead of time, and the good times go quickly. Advance planning is an absolute must.

As you may have guessed, the photo above is not from Frasca. When they start serving Spam pizza, I will return and write another review!

Heavy Snow

_DSC8529.jpg, originally uploaded by kcmckell.

Originally published Thursday, March 25, 2010

No big Earth-shattering revelations today, just a brief update.

So apparently there are some storms that make Coloradans sit down and pay attention. Oddly enough, this week’s one-day, one-night affair was one of these. I flipped on CNN the morning after to hear that “Boulder, Colorado is reporting 18 inches of snow.” I just about laughed out loud (lol’d). Out my back window, there couldn’t have been more than eight inches of wet, heavy, very much ready to melt if you looked at it for too long snow.

The local news proceeded to tell me that all schools (that were not on Spring Break) in the Denver Metro Area were closed. Many urbane city services were closed, and horror of horrors, all city libraries would be closed. This was all fairly shocking to me because I had witnessed the Front Range weather three days of continuous snowfall only a month ago. Nobody ran for shelter then. What made this little storm system any different?

It turns out that while this storm was lighter than previous ones in that it was shorter and warmer, it delivered much heavier snow. This is the kind of snow I’m used to seeing in the Sierras. Big flakes that stick to your windshield and leave big streaks of water. The stuff that fell this week was not the fluffy easily swept aside snow that falls in the colder months of winter. No, this was spring snow: Sierra Cement as I know it.

This storm brought the kind of snowflake that falls on a tree and just sits there. Then a foot of his friends join him, and suddenly there’s 40 pounds on a spindly branch that just can’t take it any more. The day after the storm, I counted no fewer than 20 limbs of various diameter down around town. I came home to blinking clocks---due no doubt to some of those limbs falling on power lines.

Now I’m beginning to understand that you can’t always judge a storm by its Doppler signature.

I would like to point out that my roommate (a native Denverer, Denverite?) enjoys telling me that Californian’s don’t know how to ski on their mountains and can’t drive in their snow. I can’t help but point out that apparently, Coloradans find it difficult to drive in our snow.

Stay dry,
Clay

Profiles of a Coffee Shop

5232CraterGraphic, originally uploaded by kcmckell.

Originally published Sunday, March 13, 2010

One of a myriad of my guilty pleasures is a cozy coffee shop. Super franchises will do in a pinch, and I appreciate the success indicated by a local chain, but it is nearly impossible to recreate the feel of a one-of-a-kind cafe. Lucky for me, Boulder has them in spades.

My friend has taken to Vic’s Espresso on Table Mesa. I have to admit, the place is jumping as early as 7:30am on weekdays. Seating is limited, so they may be pushing the to-go coffee a little bit much for my tastes. They balance the seating about 50/50 communal vs. private. The obvious selling point here is their gas fireplace and the couches surrounding it. I have to say, even the most mediocre coffee tastes like ambrosia when you’re sitting on a sofa in front of a fire with a snowstorm blowing the temperature to the low teens outside.

I would link to Vic’s, but even though it is a local chain, I can’t seem to find a website for them. So, if you find yourself in south Boulder on a cold day, head to Vic’s on Table Mesa a few blocks west of US 36.

Since moving up closer to campus, I’ve explored the cafe scene a bit. Flatiron Coffee is geographically closest to me. They have a variety of whole bean for sale, but really don’t strike me as a “hang out” type of shop.

Far and away, The Laughing Goat has earned the number one spot on my cafe list here in Boulder. Perhaps it is the novelty of a coffee-pub hybridization of my two favorite beverages that draws me here. Black coffee served in a pint glass and local beers served by the bottle (happy hour PBR tallboy for $2 wtf) blow my mind. With a front wall that opens right onto Pearl Street, there’s endless fuel for the Front Crowd (see below). The Back Crowd is satiated with multiple levels of movable tables, booths, and high-octane espresso. The house speakers play an eclectic mix (read: sometimes an iPod is necessary to drown out the wails), and waiting in occasional line inevitably yields you a helpful and energetic barista.

However, I could make myself coffee and pour it in a pint glass at home. We really come to cafes for some measure of personal interaction. As such, the Goat inevitably provides refuge to a few archetypes of arabica aficionados. Without further ado, I give you a (far from exhaustive) compilation of coffee house profiles:

The Fidgeter - This person comes to the cafe at the behest of his partner. He is not at home here and is obviously out of his element. I imagine his normal workspace consists of piles of papers and books of equal height spread over several desks. A place for everything and everything in it’s place. You can find him in the coffee shop fairly easily: He’s the one who takes six minutes to allocate space on the table for his drink, his partner’s drink, his computer, and every other trinket. This new environment must conform to his ideals in order for him to be productive. As a bonus, you might hear him complaining about how loud the music is in a very un-hip way, even though he appears young and “with it.”

The Zombie - Diametrically opposed to The Fidgeter, this person is a hermit crab and his table and chair are his shell. You might have mistaken him for a part of the eclectic decor of the shop were it not for the occasional landslide of papers emanating from his den. Once you’ve determined that there is something alive in the corner, you’ll notice his unkempt visage reminiscent of a bear emerging from hibernation. Judging by the spread of his work material, he has been here since the shop opened (possibly overnight) and is obviously under a lot of stress. My recommendation: Leave him be; any attempt at contact will at best be met with an ursine grunt and at worst will devolve into a mauling.

The Prioritizer - This person had an assignment due Friday afternoon. Alas, there was viral flash game that went around that day, and he just couldn’t find the time to edit that rough draft. Luckily, he got an extension to Monday morning! Oh joy of joys! Friday evening was spent beating himself up about how much time he wastes online and was followed by a fitful night of sleep after committing to work at the coffee shop on Saturday. At noon on Saturday, he’s all set up at the cafe table and really ready to finish this assignment he’s had on his plate for a month and a half. Out comes the 17-inch laptop and the inevitable email about the crazy stop motion video, then a bio-blog on the artist, then a three hour research bout into the logistics of processing 35,000 still frames into a five-and-a-half minute composition. Soon it is closing time. A prior engagement on Sunday means that he will end up submitting his rough draft on Monday and sliding by without realizing his potential. Again. Rinse, repeat next weekend.

The Reluctant Study Grouper - Study groups are fabulous concepts---for some people. Furthermore, coffee shops are ideal settings for the process of communal learning---at least some shops are. The conflagration of the wrong person at the wrong place is a wondrous thing to behold. Loud-ish music prevent verbal communication at reasonable levels. Small round tables leave books and binders precariously balanced like the nerves of the RSG. She may have come out of an earnest desire to learn and help learn, or she may have less noble motives. Alas, the cute one in the group couldn’t come, and now she is stuck explaining polar coordinates for the third time and not getting help with calculating the Jacobian of her moment of inertia problem. You can find the Reluctant Study Grouper by her bipolar contributions: She will alternate emphatic didactic decrees with long periods of sustained silence and supposed introspection. Also, she’ll probably leave early with a half-baked excuse. Approach with caution. Unless, of course, you can explain Jacobian matrices on the fly.

The Front Crowd (and their bitter rivals The Back Crowd) - While the geometry of every coffee shop is different, derivatives of these two ancient rivals exist everywhere. The Front Crowd is there to see and be seen. They appreciate---nay they thrive on---sustained foot traffic. They singularly derive perverse pleasure from the patron who orders a double skinny mocha, then changes their order to a half-soup to go, but finally decides upon a black tea. The barista’s customer service skills, the fashion walking by on the street, and the bits of conversation floating over the backdrop of Norah Jones are all fodder for their coffee shop experience. The Back Crowd is the yin to their yang, the conservative to their liberal, the Paul to their Yoko. The Back Crowd is here to work (or at least to appear that way...ahem, Mr. Prioritizer). White headphones are firmly implanted in their ear canals, and you will often find three good friends all at the same table looking at three different laptop screens. By the way, if you are the Lenovo to your friends’ MacBooks then yes, you are the Obby.

So how about you? Are you any of the above profiles? Do you know of another universal presence at your corner cafe?

Stay caffeinated,
Clay

Wait, Colorado?

_DSC8545.jpg, originally uploaded by kcmckell.

Originally published Monday, February 22, 2010.

I could have sworn that URL thingy up in the top of my browser says “hawaii.edu”, right?

Well, it’s true. I am a bona fide graduate student at the University of Hawaii at Manoa. That does not mean, however, that I spend all my time there. Case in point: This semester, I am living in Boulder, Colorado doing research under the auspices of “Visiting Researcher” and/or “Campus Guest.”

There are several reasons why a graduate student may want to spend some time away from his or her home institution. If the research is “portable” enough, a change of scenery may increase productivity if one goes somewhere with fewer distractions such as friends, family, and other non-academic commitments.

There are potential long term benefits as well. Working in different locations will only broaden the pool of colleagues that you know. While making new friends is always exciting, one never quite knows where future collaborations will come from, so knowing more---and different---people is a plus. Further, in this world of social networking on steroids (now there’s a Google hit just waiting to happen), we can maintain contacts like never before.

Lastly (and this plays into my love of travel), if one is lucky enough to land a job at an institution that grants sabbaticals---almost unheard of in industry---your opportunities for extended travel reduce to once every seven or ten years. Thus, why not get it in when you can?

Stay warm,

Clay

New Site!

Originally posted Friday, February 19, 2010

Welcome to my newly redesigned website!

After some minor---but persistent---ridicule, the old pure-html-written-in-notepad site gets retired today. To replace it, I’ve drawn up my first site using iWeb 3.0. Given that my previous site building experience was solely text-based, I have to say that this is a step up. However, I am not naive enough to think that this is the end-all of site builders.

Actually this is primarily a test to see whether iWeb could handle a larger task (more on that later). In the end, I don’t think this will be my go-to application to build complicated customized websites. However, it should be just fine for keeping this site up and running.

I would love to get your feedback on the redesign, but I can only enable comments if I host the site through MobileMe (lame). In the end, you’ll have to either be mute or reach me on Facebook or the like.

Cheers

-Clay