Wednesday, December 24, 2008

Gunther Receives A.A. Michelson Award

At the annual CMG International Conference in Las Vegas last week, Dr. Neil Gunther was the recipient of the prestigious A.A. Michelson Award; the industry's highest honor for computer performance analysis and capacity planning. As he said in his acceptance speech, it was the fulfillment of a dream he had entertained at his first CMG Conference in 1993.

His presentation was unusual in that, rather than reviewing his own accomplishments, he presented a personal view of the experimental physicist Albert A. Michelson (after whom the award is named), his famous null measurement of the luminiferous aether, and its significance for both physics and computer management today; particularly in the context of the search for the Higgs boson at the LHC. As a theoretical physicist, Gunther holds the view that the Higgs will probably not be observed, many false positives notwithstanding. Like the aether search, it may well end up as the next famous null experiment.

Link to the announcement in Linux Magazin: click here.

Monday, December 22, 2008

Transitioning colors: glaucus

In Switzerland, when I was a pupil in elementary school, at the beginning of the school year we used to receive a small box of colored pencils in the main colors. The first years of school were spent learning the names and semiotics of those colors, as well as depicting our environment.

It was only later in elementary school that I learned a new color name, namely glauco. It was in a poem from our textbook, that we had to memorize.

The Zanichelli vocabulary translates glauco into English as blue-green, sea-green, glaucous. I guess the readers of this blog will be familiar with this color name from glaucoma, a condition of increased pressure within the eyeball, causing gradual loss of sight.

Today in Italian, glauco is associated most commonly with eye colors, because of the gray-green haze in the pupil.

Why am I counting this color among the transitioning colors? Over time, this color label is one that has changed quite dramatically in its association with a perceived color.

It starts with eye colors. My Sanesi classical Greek vocabulary from high school lists the following classical terms, in alphabetic order (apologies for the missing accents):

  • γλαυκιαω, to have an inflamed look
  • γλαυκ-ομματος, with inflamed eye
  • γλαυκος, scintillating, brilliant, shining || cerulean, azure
  • Γλαυκος, name of many characters
  • γλαυκοςτης, luster, shine of the eyes || cerulean color
  • γλαυκο-χρως, of azure color, of olive and pale color
  • γλαυκ-ωπις, of the shining, brilliant, cerulean eyes

In summary the classical use was for the shining color of eyes, mostly light blue, for example the color of Athene's eyes (glaukopsis). However, in the Homeric epics it has been used also for dark blue. Strangely, γλαυκο-χρως has been used also for olive and pale colors.

This strange use might at first explain why then in the later Middle Ages the meaning of the derived Latin term glaucus changed dramatically from blue-gray to yellow. Instead, I would like to speculate here that it might be connected to the loss of diphthongs as Latin became vulgarized.

In my Campagnini-Carboni classic Latin vocabulary from middle school I find these two definitions:

  • cærúleus, cerulean, azure, turquoise, dark; cærula cæli, or simply cærula, the azure, the azure sky
  • cerula, piece of wax

As you see, as the diphthongs were dropped with the vulgarization of Latin, cerulean blue might have become the color of wax. Indeed, Roger Bacon (~1214-1292) used glaucitas to refer to yellowness and ceruleus (wax color) as a yellow color falling between glaucus and citrinus (yellow and orange, respectively).

In the 14th century, Theodoric of Freiburg used glaucus with the same meaning. But then, in the mid-16th century, Scaliger (1557) put it back in the blue category, where it still was in the beginning of the 17th century with Francois d'Aguilon. (This data from Kuehni and Schwarz, Color Ordered, p. 8.)

If the label purple changed as a consequence of the collapse of a major civilization, the label glaucus might have been done in by an overworked or sloppy monk. In this case, γλαυκο-χρως used for olive and pale colors can be a medieval mistake rather than a genuine classical Greek color label.

Make sure, you dot your is and cross your ts, and watch out for those pesky diphthongs!

Wednesday, December 17, 2008

さきみだれる = blue light + cryptochrome 2

We scientists have a special way to ruin a poetic or romantic moment. For example, we might be sitting in front of the most powerful sunset, and all that we can think of is Rayleigh scattering and how what we see is just the effect of the fourth power on the frequency factor.

And now another natural phenomenon might be ruined: 咲き乱れる (さきみだれる), for which we do not even have a proper translation — it took a Japanese haiku master to come up with such a concept.

Here is how the editors of Science summarize the paper by Liu et al. from the department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles:

Plants respond to light with a variety of developmental and physiological changes. The receptor for the blue-light wavelengths is cryptochrome. How blue light causes cryptochrome to alter cellular function has been a puzzle. Now, using a yeast two-hybrid screen, Liu et al. have identified a protein from Arabidopsis, CIB1, which, in the presence of blue light, interacts with the cryptochrome. CIB1 and cryptochrome colocalize in the plant cell nucleus, where CIB1 functions as a transcription factor. Together, these proteins bring the input of blue light into the signaling pathways that regulate flowering.

By the way, this cryptochrome mechanism is one of these tricks Nature is using over and over, in us humans too. CIB1, which is short for cryptochrome-interacting basic-helix-loop-helix, appears to affect primarily the amplitude, but not the period, of the circadian rhythm of the FT mRNA expression. Therefore, next time you complain about jet-lag, think the same mechanism also controls floral initiation and more poetically, 咲き乱れる.

Now, if we could only remember how to let a thousand flowers bloom in research labs!

Click this link to access the paper: Photoexcited CRY2 Interacts with CIB1 to Regulate Transcription and Floral Initiation in Arabidopsis.

Wednesday, December 10, 2008

Transitioning colors: purple

In my post on the ephemerality of color names I wrote that color names can go out of fashion and then the label of a given color is lost. It also happens that a label is persistent, but the color associated with that name changes. Purple is such an example.

Nathan's color thesaurus responds to "porpora" with the color of hexadecimal value b23372, which looks like

However, if we look at this old mosaic in San Vitale in Ravenna, we see a different color for the same label "porpora":

What happened?

From Phoenician times the purple colorant was extracted from molluscs living in the coast of present day Lebanon and Israel. It was a rare colorant, hence used only for textiles destined to the rich and powerful. In fact, in 1464 Pope Paul II decreed that cardinals have to wear purple.

By coincidence this was the time the Byzantine empire crumbled and in the Ottoman empire the Purple industry in the Eastern Mediterranean disappeared. Hence, the tailors had to switch to a red colorant, but the papal decree cast the label "purple" into concrete.

If today you visit a religious clothing store, when you ask for Purple you will get a red cape, as shown below. In this case, Italian crowdsourcing returns Purple more to the original color, but not quite.

This is a big problem for restorers. As you might have seen in the Sixtine Chapel or Leonardo's Last Supper, today's restorers are very aggressive in restoring the original colors, instead of just freshening up the old paint in its current state.

One way to figure out the original colors is to study the master's notebooks and find textual descriptions of the colors. Unfortunately, for a given label, the colors transition, especially today when all paints care constantly reformulated to make them less toxic.

Anyway, these color transitions is exactly why Prof. Giovanni Brini in Torino has compiled his comprehensive color name dictionary. It is intended for restorers who have to pin-point the color for a given name at a given date.

Tuesday, December 9, 2008

A wimp's 40th birthday

Industry analysts generally equate modern personal computing with the GUI, or graphical user interface. Therefore, March 1992 is generally seen as the birth of the PC, namely the release date of Windows 3.1.

There is then another group of analysts that then counters the GUI was really invented on 24 January 1984 when the Macintosh was released. Of course others then claim the GUI is older than that when Smalltalk with its WIMP paradigm was invented at Xerox PARC.

Actually, the WIMP paradigm is even older than PARC. The PC was really invented concomitantly with the mainframe, and the main person behind it was "Lick" Licklider. You can read up the PC's history in M. Mitchell Waldrop's "The Dream Machine."

Anyway, the acronym is WIMP, which stands for windows, icons, mice, and pointing. That goes back to 40 years ago.

It the PC's history was linear, today we would use them to solve partial differential equations. The basic idea was time sharing, later called adaptive computing and today called cloud computing. Not a reason to spend money on an iPhone, Blackberry, or Netbook.

The paradigm shift occurred in San Francisco on 9 December 1968 at 1 p.m. at the ACM conference, when Doug Engelbart demonstrated his On-Line System or NLS. It was about augmenting human intellect, and in a single demo (a.k.a. The Mother of All Demos) he introduced concepts like windows, hypertext, mice, cording keyboard, collaborative software (groupware), video chatting, networking, and more to a stunned crowd still using punched cards.

The celebrations are this afternoon at Stanford in the Memorial Auditorium.

Happy Birthday, WIMP!

The ephemerality of names

From the paper mentioned in my post of 2 December we know that color categorization is probably mediated by language, which is what is meant by the statement "a form of categorical perception that is lexically influenced." The next problem is how to deal with the ephemerality of language.

Languages are in constant evolution (well, maybe with the exception on French, where bytes are still called octets). For example, in Japanese the katakana script that was originally used for bureaucratic and male writing, has been repurposed to write words of foreign origin — and how many foreign words there are! Look at something as common as milk, which used to be 牛乳 (ぎゅうにゅう, gyuunyuu) but now is simply ミルク (miruku).

Closer to home, consider late ETH Prof. Heinrich Zollinger's work ca. 1975, where he collected color names from TKD chemistry students:

The ordinate is the frequency of occurrence for the name of the Munsell hue in the abscissa. Note how オレンジ (orenji) is more frequent than 橙 (ダイダイ, daidai) and ピンク (pinku) is more frequent than 桃色 (ももいろ, momoiro).

Maybe the change of the Japanese language is a bit extreme, but English is also changing fast, especially for words related to fashion, like color names. Look for example at the names in Coloroid hue 20 I showed last week:

Did you know the color name Arsigont? Did you know the difference between Pompeian yellow and Indian orange?

This is not a problem of the Coloroid system. Consult any color name compilation older than a few years, and you will find names that look unfamiliar. For example, a decade ago teal was all the rage in Palo Alto and all home decoration stores were selling many items in this color. Today, people hardly remember its appearance.

So, how do we deal with the ephemerality of language? Obviously a printed leather-bound collector's edition of a color dictionary is not the ticket. The ephemerality of a blog tool post is more like it. But color names are very hard to collect, we cannot start from scratch every few months.

This is why in the Italian version of his color thesaurus, Nathan included a mechanism to rate the pairing of the color name with the displayed color. As names fade, they get rated worse and by using the rating in the creation of the thesaurus, a more contemporary color name will emerge to label that color.

Saturday, December 6, 2008

Colored geese

When I did my first steps in image processing, researching new algorithms was not for the faint of heart. First you had to be a maestro programmer (a.k.a. wizard) because to get the algorithm to run with a usable performance on a sub MHz processor with 64K bytes of memory you had to write a paging algorithm to fit it all in memory and code the inner loops in octal code so not to miss any clock cycles and work directly on the barrel shifter. You also had to stick an exception handler at the beginning of the boot loader to catch processor faults and get a chance at debugging your algorithm.

A first quantum leap happened when Photoshop came out, because you could first try out things interactively, then you could write a plug-in with your algorithm.

The next quantum leap happened with MatLab, which contains well programmed image processing libraries that allow you to quickly implement your algorithm expressing it as a linear algebra problem.

A new quantum leap is happening now with Mathematica, which now allows images as parameters, contains an image processing library, and gives you the full power of symbolic computing. Read more about it in this blog post by Theodore Gray. [Click the image to view the movie.]

Colored geese--click to view movie

Many thanks to Don O'Shea for the pointer.

Tuesday, December 2, 2008

Categorical color perception moves from right to left hemisphere across life span

It feels a very long time ago when in 2003 I was assigned to solve a problem in variable data printing — when colored text is printed on a colored background and the colors are variable, the text may become unreadable. Since each copy is different in a variable data job, manual proofing is not feasible and an algorithm is required.

Conventional colorimetry is of no use, because it deals with color matching — small color differences — not the large color differences to be considered in readability issues. Required to quickly deliver some code, I came up with a heuristic based on ∆E units. Silvia Zuffi and Carla Brambilla of the CNR in Milano-Bicocca have revisited that work and performed genuine research replacing my heuristics.

Once the code was delivered, I implemented a different algorithm more suited to the task. As the research by Zuffi and Brambilla shows, the readability problem can be formulated as a reading speed problem. From Stevan Harnad's work we know that color discrimination is faster for colors in different perceptual color categories than for colors in the same perceptual categories, when their perceptual distance (∆E) is fixed.

The most obvious way to introduce structure in a color space, i.e., to introduce perceptual color categories, is by considering color names. The new problem now is to find a 3-dimensional tiling of a color space. I had the data for Nemcsics's names in the Coloroid system, so I implemented that.

The implementation of the readability solution was then straightforward. I used the lexical distance between the two colors and required at least 2, i.e., there had to be at least a color name between the two color's names.

The solution performed only so-so. In fact, there were a number of issues.

  1. The transformation from CIE tristimulus is only published in part and required a lot of experimentation to pin down
  2. This transformation is numerically instable, so an industrial-strength implementation that never fails is not trivial and requires skilled programing
  3. The tiling does not cover the whole gamut, so it needs to be "stretched"
  4. There is no reference in the literature on the origin of the categories and names — did Nemcsics cook them up heuristically?

But the biggest question is: are the color categories mediated by language? Is it legimimate to use color names for a lexical metric? Each time I put up my old color cognition diagram

co-blogger Nathan Moroney always interjects that color categorization may occur much earlier. The paper Categorical perception of color is lateralized to the right hemisphere in infants, but to the left hemisphere in adults in a recent issue of the Proceedings of the National Academy of Sciences comes very close to answer this question.

Franklin et al. take advantage of the difference between the left and the right hemisphere of our brains (let us assume for a moment we are all right-handed and have a normal corpus callosum) that the left hemisphere is geared to encoding categorical or relational information, while the right hemisphere is geared towards encoding metric information.

The linguistic hypothesis in color categorization is that colors are tagged by their category name and the tags are compared, i.e., that language mediates categorical color perception. The question is whether the color categorization is prelinguistic, i.e., whether there is a universally available color categorization and language just makes some minor adjustments, or color categorization is built from scratch after language is available.

Franklin et al. used a group of 21 years old right-handed adults and a group of 21 week old infants and compared their categorical color perception skills, obtaining these results:

(remember the neural axons get crossed in the optical chiasm). Categorical color perception is found in infants; however, the absence of a category effect in the left hemisphere for infants, but the presence of a greater left hemisphere than right hemisphere category effect for adults, suggests that language-driven categorical perception in adults may not build on prelinguistic categorical perception, but that language instead imposes its categories on a left hemisphere that is not categorically prepartitioned.

Their findings therefore suggests that there is a form of categorical perception that is nonlinguistic and right hemisphere based (found in infancy) and a form of categorical perception that is lexically influenced and biased to the left hemisphere (found in adulthood). Categorical color perception is found for both infants and adults, but the contribution of the left hemisphere and right hemisphere to categorical color perception appears to change across our life span.

Our digital presses are for adults, so my approach is valid.