Archive for category Uncategorized
Evolutionary operation
Posted by mark in design of experiments, Uncategorized on March 7, 2010
Last December, after an outing by the Florida sea, I put out an alert about monster lobsters. This reminded me of an illustration by statistical gurus Box and Draper* of a manufacturing improvement method called evolutionary operation (EVOP), which calls for an ongoing series of two-level factorial designs that illuminate a path to more desirable conditions.
With the aid of Design-Expert® software, I reproduced in color the contour plot in Figure 1.3 from the book on EVOP by Box and Draper (see figure at the right). To illustrate the basic principle of evolution, Box and Draper supposed that a series of mutations induced variation in length of lobster claws as well as the pressure the creatures could apply. The contours display the percentage of lobsters at any given combination of length and pressure who survive long enough to reproduce. Naturally this species then evolves toward the optimum of these two attributes as I’ve shown in the middle graph (black and white contours with lobsters crawling all over them).
In this way, Box and Draper present the two key components of natural selection:
- Variation
- An environment that favors select variants.
The strategy of EVOP mimics this process for improvement, but in a controlled fashion. As illustrated here in the left-most plot, a two-level factorial,** with ranges restricted so as not to upset manufacturing, is run repeatedly – often enough to detect a significant improvement. In this case, three cycles suffices to power up the signal-to-noise ratio. This case illustrates a big manufacturing-yield improvement over the course of an EVOP. However, any number of system attributes can be accounted for via multiple-response optimization tools provided by Design-Expert or the like. This ensures that an EVOP will produce more desirable operating conditions overall for process efficiency and product quality.
It pays to pay attention to nature!
*Box, G. E. P. and N. R. Draper, Evolutionary Operation, Wiley New York, 1969. (Wiley Classics Library, paperback edition, 1998.)
**(We show designs with center points as a check for curvature.)
Beware of bugs bearing backpacks
Posted by mark in science, Uncategorized on March 3, 2010
I am attending a conference sponsored by the National Defense Industry Association (NDIA). They provided all of us participants a copy of the latest issue (March) of their publication National Defense. While wiling away the time listening to some long-winded higher-ups I paged through the magazine and admired the weaponry developed to keep our war-fighters supported to the max. However, on page 17 a very odd picture caught my eye – a cockroach carrying a radiation sensor on its back! A researcher at Texas A&M reports that these bugs are ideal for sweeping potentially contaminated areas, ideally in teams of twenty. They can be operated remotely via devices that stimulate their leg muscles.
There is one problem though: Cockroaches cannot crawl backward. One had better hope that none of the bad guys wear pointy-toed cowboy boots, because they will be ideal for killing the sensor-bearing bugs that become stuck in the corners.
Simplifying the witches brew in Shakespeare’s MacBeth
Posted by mark in Uncategorized on February 14, 2010
Last week I enjoyed an innovative performance of Shakespeare’s MacBeth at the Guthrie Theater in Minneapolis. The director, Joe Dowling, takes some liberties with the original production, such as dropping the warrior MacBeth on stage down a ninja rope and equipping him with a machine gun. However, mostly the gruesome killings that riddle this dark play are accomplished with old-fashioned daggers and swords.
Being a chemical engineer who abhors overly complicated recipes, it bothers me that the three weird sisters in Macbeth put so many ingredients into their witches brew. It would be very hard to scale up their potent product from bench-level kettle to massive manufacturing. By the way, thanks to this heads-up by Nigel Beale I cracked this coven’s confidential code on components; for example, eye of newt, which cannot be easily sourced, is really readily-available mustard seed. Nevertheless, I’ll bet that a good mixture screening experiment, followed-up by an in-depth formulation design, such as this one on a cell-culture medium, would reveal that only a few key ingredients might do the job for enabling clairvoyance or whatever a witch might be up to.
Keep it simple, I say. Or as Shakespeare advises more eloquently, “Brevity is the soul of wit.”
Apples and oranges comparison of diets?
Posted by mark in science, Uncategorized, Wellness on January 21, 2010
While exercising on my elliptical machine this morning watching ABC’s Good Morning America the show captured my attention with a report that Weight Watchers (“WW”) this week filed a lawsuit against one of its top competitors, Jenny Craig (“JC”). The dispute stems from a claim by JC that their clients lost, on average, over twice as much weight as those on the largest weight loss program. WW alleges that this claim is deceptive due it comparing a study by JC done this year versus one done by WW 10 years ago. According to this news release by Weight Watchers the complaint states that generally accepted standards of biomedical research require Jenny Craig to compare the two current offerings of both companies through a head-to-head randomized clinical trial.
“You can’t compare studies that were done in different locations at different times using different groups of people.”
– Louis Aronne, M.D, New York Presbyterian Hospital weight loss expert and author of Eat This, Not That
Although the judge has put a temporary restraining order against their offending ad, I wouldn’t rule out the JC claim prima facie. After all, as Smartmoney Magazine writer Angie Marek stated in her column on The Skinny on Big, Fat Diet Programs “the science on most of these plans is hardly conclusive, since most of the research has been paid for by the diet companies themselves.” In fact, I predict that this case will keep at least two statisticians fat and sassy as expert witnesses (one on each side of this tug-of-war).
Marketing researchers go curb mining for treasure in the trash
Posted by mark in Uncategorized on January 16, 2010
The January Twin Cities Business magazine reported “A Real Good Marketing Experiment” that I found intriguing. Minneapolis-based Blu Dot Design and Manufacturing researchers abandoned 25 of their Real Good chairs on New York City sidewalks. See the results in this very entertaining eight-minute film.
“Once in a while you find some really good stuff.”
– A ‘Punko’ (scrounger) in the Real Good chair experiment.
In our suburban neighborhood we put out furniture and tape a sign on it that says “Free.” Whenever I’ve done this, the item has disappeared. A few times I’ve spied a person carting it off, but most stuff goes off with the garbage, I guess.
I suggest that the next time Blu Dot tosses out chairs they do a proper design of experiment (DOE). The measure of success will be how long it takes for a particular unit to be scrounged. The experimental factors will be color and various design elements. Of course the chairs must be laid out according to a randomized plan.
Stat-Ease performed a very simple, but statistically powerful, experiment on the chairs it considered for purchase in a new training room. See the details in this lead article of the June 2002 Stat-Teaser newsletter.
Management Blog Carnival, Review 3 – Seth Godin blog
Posted by mark in Uncategorized on January 3, 2010
(Note: This blog is the last of three in a carnival organized by John Hunter.
I picked the Seth Godin blog to review because his name rang a bell, but I’d never read anything by him that I specifically recall. As it turns out, I really did not see much that interested me greatly for exactly the opposite reason expressed in this comment by “ariana10” to Godin’s blog of 8/22 (bulleted below):
“I relate to this blog because I am a journalism major at the University of Kansas and I can’t do math for the life of me.”
I am an engineering major who likes math (in moderation!) and I can do it for the life of me. However, I am also keen on marketing and business (MBA, U Minn., ’80) so, even though Godin is light on stats, I must admit that he’s got much to offer for those of us trying to make a living in this high-tech world. Here are a few Seth Godin blogs of 2009 that hit my hot buttons.
- 1/24 Good guys finish… Godin suggests that under the bright light of the internet being generous and fair in business dealings pays off now more than ever. I like that idea a lot.
“When your customer service policies delight rather than enrage, word of mouth more than pays your costs.”
- 8/22 Not so good at math demonstrates the confusion creating by using miles per gallon (mpg) as the metric for fuel efficiency. As I noted in my blog on how the Inverse transformation puts mileage comparisons on track / the best measure for fuel efficiency is gallons per ten-thousand miles.
- 8/28 Spare no expense! does get somewhat quantitative (finally a graph!) in discussing the tradeoffs of giving almost no personal service to a huge number of users (Google) versus a great deal of attention to the troublesome individuals who soak it up.
- 10/26 Dunbar’s Number isn’t just a number, it’s the law is where Godin, a people person, draws the line at 150 – the limit predicted by British anthropologist Robin Dunbar for stable social relationships. I think the number might be a lot less (a tenth?) for engineers than marketers. ; )
What sets Seth Godin’s blog apart from the others I’ve seen (admittedly a small sample) is the amount of original content laced with thought-provoking observations of how people interact and what turns them on or off. He’s a guy worth keeping an eye on, I think.
Management Blog Carnival, Review 2 – “Hexawise” by Justin Hunter
Posted by hank in design of experiments, Uncategorized on January 1, 2010
(Editor’s note: This blog is contributed by my son Hank – a programmer by profession. It’s the second of three in a carnival organized by John Hunter. -Mark)
Justin Hunter is the founder of Hexawise, a SaaS tool that aids in setting up tests for software using statistical methods. This also happens to be the subject of his blog – no doubt influenced in part by his father, William Hunter, author of the classic text Statistics for Experimenters. Justin started the blog mid-way through ’09, so the pickings are a little slim, but there is still plenty of good stuff.
Some highlights from 2009:
- 10/6 The Stackoverflow.com for Software Testers marks the release of a beta version of testing.stackexchange.com. This is a community driven Q and A site that uses the same technology as Stack Overflow, a popular site for coders looking for help. Hunter’s version is aimed at testers, and already has an impressive database of answers and discussion.
- 8/25 What Else Can Software Development and Testing Learn from Manufacturing? Don’t Forget Design of Experiments (DoE) links to a Tony Baer post comparing software development to the manufacturing industry. Hunter further focuses on the application of Design of Experiments, pointing out the extensive use of DoE in quality improvement initiatives in Toyota and Six Sigma. These initiatives have yet to really penetrate the software development industry, despite some high profile successes (Google’s Website Optimizer and Youtube are mentioned).
- 12/9 Defect Seen >10 Million Times and Still not Corrected has some interesting trivia about the grammatical error in Lands’ End – something I hadn’t even noticed, and apparently the company hadn’t either until it was too late. The real point of the post, however, is to point out another much more fixable grammatical error in Google’s Blogger software. If there is only 1 comment on a post, it still says “1 comments”, instead of dropping the s. A trivial defect, perhaps, but a very visible and easily fixed one. It reminds me of something Mark always says about taking a break from work to sweep the dirt off the shop floor. That is, you shouldn’t let the little inconsequential bugs pile up while you’re focused on the big ones.
On a lighter note, in Famous Quotes that Make Just as Much Sense When You Substitute PowerPoint for Power Justin linked to a post by Jerry Brito about substituting PowerPoint for Power in famous quotes, adding a few of his own. I’d also like to add:
Kirk: “Spock, where the hell’s the PowerPoint you promised?”
Spock: “One damn minute, Admiral.” –Star Trek IV
Favorite posts from three rings in a carnival of management blogs: Round 1 – “Work Matters” by Bob Sutton
Posted by mark in Uncategorized on December 28, 2009
John Hunter, being a son of quality guru Bill Hunter, appreciates the value of design of experiments (DOE) for process improvement. He often mentions DOE in his blog The Curious Cat Management Improvement Site — with this StatsMadeEasy blog being cited on a few occasions. I keep tabs on Curious Cat to see what John turns up that might hit a hot button for me. So when John asked me to participate in this year’s Annual Management Improvement Blog Carnival, I readily agreed to join a number of other bloggers favored by him to select top 2009 posts from within our community.
See us hosts and the blogs we’ve chosen to review at this site coordinated by John. As you can see, StatsMadeEasy is culling the best of these bloggers:
This last blog – one of many proffered by John that focus on agile programming – is reviewed by my son Hank, who codes for Stat-Ease.
Bob Sutton offers many impressive credentials but the one that caught my eye was Weird Ideas That Work – a book he authored. I’m always on the lookout for non-intuitive approaches that improve process effectiveness. One of Sutton’s suggestions is to “increase variance in available knowledge.” That’s a good twist for an aficionado of stats!
Here my favorite 2009 posts by Bob:
- 1/20, Brainstorming: Pros and Cons provides a balanced view of whether it works to gather a group for generation of ideas. I’ve been intrigued by this since my days as a Product Manager at General Mills (chemical division) when I would lead brainstorms with our R&D scientists and engineers. Note the comment by blogger Keith Harmeyer (SmartStorming) that “the ideal situation is a combination of solo ideation and brainstorming.” I agree with that because it draws out ideas from the introverts — perhaps propensity to speak one’s mind is inversely correlated to quality of comment. ; )
- 3/9 Dilbert and The Smart Talk Trap re-tells a story from Weird Ideas That Work in which a brainstorming leader at Microsoft asked “What would be the worst product we could possibly build?” His idea was to think opposite but, of course, the crazy idea is what management liked. Coincidentally I was watching the movie Revolutionary Road, which features a cynical worker in a downtrodden ‘50s office (played wonderfully by Leonard DiCaprio) who, after deciding to quit this rat race, fires off a flippant flyer to the Toledo branch. This then gets him a promotion for thinking out of the box!
“Ideas that seem dumb may have more merit than you think.” — Bob Sutton
- 7/6 Wisdom, Randomness, and the Naskapi Indians provides a good example of how one can often benefit by choosing a direction at random. This works well for me when deciding at poker game whether to bluff or not. I won’t say anything more because one of my buddies might read this, so it would cost me.
- 10/7/09 Squeaky Wheels, The Health Care Debate, and Student Complaints About Grades reveals how Sutton, a professor at Stanford University, deals with students who complain about grades. Being a stoic Minnesotan who was taught to grin and bear it, I like his thinking on this!
- 11/1/09 Intuition vs. Data-Driven Decision-Making: Some Rough Ideas supports Sutton’s view “that intuition and analysis are not opposing perspectives, but tag team partners that, under the best conditions, where hunches are followed and then evaluated with evidence…” My world of statistical design of experiments is data driven, of course. However, the big breakthroughs in process and product improvement often come from subject-matter experts who come up with a brilliant hunch that pans out. The classic book on DOE Statistics for Experimenters, co-authored by Bill Hunter (the father of John Hunter who is the ring-master for this carnival of blogs), begins with a wonderful treatise on induction versus deduction that I recommend to all experimenters.
I would be remiss not to provide a heads up to the elephant in the room at the Work Matters blog: Sutton devotes many of his posts to the bad behavior of bosses – a bugaboo for me too. The difference is that I keep my expletive (***hole!!!) private, whereas Sutton is brave enough to shout it out. Most of you may find this scintillating, but those who consider prim to be professional: Be forewarned about some rough language. One of the tamer and thought-provoking posts (29 comments) is the October 18th one asking Do You Learn More from Working for a Bad Boss than a Good Boss? Another post that takes the high road came on December 22 (just the other day) relating The Boss’s Journey: The Path to Simplicity and Competence. Being of a certain age (not far from Bob’s) I had to chuckle at his story of a student who disrespected managers until becoming the boss of a small product development team made him realize how hard this role can be.
Pushing the limits on alcohol levels for holiday cheer – higher the better (?)
Posted by mark in Uncategorized, Wellness on December 24, 2009
Just in time for holiday gift-givers to the guy who already owns everything, Boston Beer Company (BBC) — brewer of Sam Adams lager — announced this year that they’d achieved new heights for alcohol content – over 25 percent by volume. Alcohol levels traditionally have been capped at the 14% level due to natural limits of the yeast that drive fermentation. However, the beer boffins at BBC applied their wits to the zymurgy and came up with “Utopia,” which can be purchased at $599.99 a mini-kettle via this internet purveyor (warning: it’s banned in 13 states!). Otherwise you can await the next batch of ten thousand bottles or so of this potent beer to emerge in two years from the 15-year aging cycle.*
Perhaps this holiday season you may restrict yourself to tamer drinks than high-alcohol beer, such as the traditional eggnog — a “sweetened dairy-based beverage made with milk, cream, sugar, beaten eggs (which gives it a frothy texture), and flavored with ground cinnamon” (according to Wikipedia). However, my plans to pick up our annual eggnog after Thanksgiving were dashed after listening to a recent radio broadcast of NPR’s Science Friday by Ira Flatow. They warned about people (like me) risking salmonella-induced food poisoning by milking their ‘nog clear through Christmas. The show posted this video reporting results from microbiologist Vince Fischetti on his challenge tests** in a lab at the Rockefeller University (RU). I’ve seen these at food clients of Stat-Ease and they gross me out, so I know the end result of dosing up a dairy product with spoilage organisms and pathogens cannot be pretty. Fischetti compared the results after one month of storing a spiked eggnog made by a traditional RU recipe (equal parts bourbon and rum to a 20 % alcohol level) versus one purchased commercially (no alcohol). See the outcome by watching the video – it may encourage you to keep a bottle of spirits on hand. (I’ve got a supply of tequila – just in case.) Being a devotee of DOE, I must say that Fischetti’s findings appear to be based only on sample-size 1. But to his credit, he expresses the desire for grant money leading to more definitive studies.
So whether you hoist a beer or a ‘cheered-up’ glass of eggnog to give your seasonal salute to your friends and family, here’s hoping you all a happy holiday!
*Source for news about high-alcohol beer: 11/30/09 article by Russell Contreras of the Associated Press, seen here as published by the Huffington Post.
** For all the gory details see this posting of Microbiological Challenge Testing by the Institute of Food Technologists (IFT). The “Phoenix” phenomenon is particularly worrying (lethal bugs rising from the ashes of sterilization).
The State of happiness
Posted by mark in Uncategorized, Wellness on December 20, 2009
Those of you American citizens who (like me) enjoy our unalienable pursuit of happiness should see where your home State ranks in this list presented by economists Andrew Oswald and Stephen Wu.
Our local newspaper headlined this report with the suggestion that we Minnesotans “try living in a sunnier State.” I have a hard time arguing with moving to Hawaii or Florida – both near the top the Oswald-Wu list. Louisiana (#1) is a good choice too, I think, despite the setback of Hurricane Katrina. I spent time there and in the neighboring State of Mississippi (#7) last March – a great time to get out of Minnesota (#26). However, I really do enjoy our winters here in the northernmost part of the lower 48. At this time of the year our sun sits nearly at its lowest point (Winter solstice being mid-day tomorrow), which makes any rays one can catch all the more dear.
This morning a little Canadian ‘clipper’ topped off our existing blanket of snow with another inch of sun-sparkled crystals. It was good to be outdoors walking the dog through our little “Sunwood” park of evergreens again after taking a little break on our daily strolls last week due to the bitter cold. Maybe it was just as well we stayed home because a cougar came through our neighborhood (called “Croixwood”) as evidenced by the huge paw print pictured here . The cougar was last sighted in Wisconsin. My guess is that this cat is headed for Florida. =^.^=