Author Archives: curiouscat

The Million Dollar Programming Prize

One of the main areas of collaborative filtering we exploited is the nearest-neighbor approach. A movie’s “neighbors” in this context are other movies that tend to be scored most similarly when rated by the same viewer. For example, consider Saving Private Ryan (1998), a war movie directed by Steven Spielberg and starring Tom Hanks. Its neighbors may include other war movies, movies directed by Spielberg, or movies starring Tom Hanks. To predict a particular viewer’s rating, we would look for the nearest neighbors to Saving Private Ryan that the viewer had already seen and rated. For some viewers, it may be easy to find a full allotment of close neighbors; for many others, we may discover only a handful of neighboring movies.
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A second area of collaborative-filtering research we pursued involves what are known as latent-factor models. These score both a given movie and a given viewer according to a set of factors, themselves inferred from patterns in the ratings given to all the movies by all the viewers [see illustration, “The Latent-Factor Approach“]. Factors for movies may measure comedy versus drama, action versus romance, and orientation to children versus orientation to adults. Because the factors are determined automatically by algorithms, they may correspond to hard-to-describe concepts such as quirkiness, or they may not be interpretable by humans at all.
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The model may use 20 to 40 such factors to locate each movie and viewer in a multidimensional space. It then predicts a viewer’s rating of a movie according to the movie’s score on the dimensions that person cares about most. We can put these judgments in quantitative terms by taking the dot (or scalar) product of the locations of the viewer and the movie.
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We found that most nearest-neighbor techniques work best on 50 or fewer neighbors, which means these methods can’t exploit all the information a viewer’s ratings may contain. Latent-factor models have the opposite weakness: They are bad at detecting strong associations among a few closely related films, such as The Lord of the Rings trilogy (2001–2003).

Because these two methods are complementary, we combined them, using many versions of each in what machine-learning experts call an ensemble approach. This allowed us to build systems that were simple and therefore easy to code and fast to run.

Interesting article. See some other posts on challenge prizes.

Read: posts on programing – Problems Programming Math – Programmers (comic)

Using Barn Owls for Bilogical Pest Control in Israel

Using Barn Owls (Tyto alba erlangeri) For Biological Pest Control In Israel

Agricultural pests come in all forms, but worldwide it is small mammals, mostly rodents, that are responsible for the destruction of about 35% of the total world agriculture. To combat rodents, farmers use rodenticides. However, these pesticides are relatively ineffective as they are short-lived
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During the late 1960’s, hundreds of birds of prey (some of them threatened and endangered species) were killed throughout Israel from secondary poisoning after eating rodents that had been poisoned with rodenticides.
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Once farmers grasp the concept that their ‘winged’ neighbours can help to solve rodent damage if they stop using poisons, Barn Owls and Kestrels will be able to rise to the occasion and control rodents. By living in harmony, both farmers and these birds will be able to benefit from living in co-existence. As we are just beginning to understand the power of nature we realise its many economic benefits, even in modern times. As Barn Owls and Kestrels truly know no boundaries, they not only solve economic problems, but are also bringing peoples together. This is very much needed in the Middle East.

Great stuff.

Tiny Machine Commands a Swarm of Bacteria

Researchers in Canada have created a solar-powered micro-machine that is no bigger than the period at the end of this sentence. The tiny machine can carry out basic sensing tasks and can indirectly control the movement of a swarm of bacteria in the same Petri dish.

Sylvain Martel, Director of the NanoRobotics Laboratory at the Ã‰cole Polytechnique de MontrÃ©al, previously showed a way to control bacteria attached to microbeads using an MRI machine. His new micro-machine, which measure 300×300 microns and carry tiny solar panels, will be presented this week at ICRA ’09 in Japan.

On such a small device there is little room for batteries, sensors or transmitters. So the solar cell on top delivers power, sending an electric current to both a sensor and a communication circuit. The communication component sends tiny electromagnetic pulses that are detected by an external computer.

The sensor meanwhile detects surrounding pH levels–the higher the pH concentration, the faster the electromagnetic pulses emitted by the micro-machine. The external computer uses these signals to direct a swarm of about 3,000 magnetically-sensitive bacteria, which push the micro-machine around as it pulses. The bacteria push the micro-machine closer to the higher pH concentrations and change its direction if it pulses too slowly. This is more practical than trying to attach the bacteria onto the micro-machines, says Martel, since the bacteria only have a lifespan of a few hours. “It’s like having a propulsion engine on demand,” he says…

Intel Science and Engineering Fair 2009 Webcasts

Tara Adiseshan, 14, of Charlottesville, Virginia; Li Boynton, 17, of Houston; and Olivia Schwob, 16, of Boston were selected from 1,563 young scientists from 56 countries, regions and territories for their commitment to innovation and science. Each received a $50,000 scholarship from the Intel Foundation.

(video removed, so the embed code has been removed)

In the webcast, Tara Adiseshan, talks about her project studying the evolutionary ties between nematodes (parasites) and sweat bees. She identified and classified the evolutionary relationships between sweat bees and the nematodes (microscopic worms) that live inside them. Tara was able to prove that because the two have such ecologically intimate relationships, they also have an evolutionary relationship. That is to say, if one species evolves, the other will follow.

Li Boynton developed a biosensor from bioluminescent bacteria (a living organism that gives off light) to detect the presence of contaminants in public water. Li’s biosensor is cheaper and easier to use than current biosensors, and she hopes it can be used in developing countries to reduce water toxicity. Li Boynton on What’s Great About Science:

Olivia Schwob isolated a gene that can be used to improve the intelligence of a worm. The results could help us better understand how humans learn and even prevent, treat and cure mental disabilities in the future.

In addition to the three $50,000 top winners, more than 500 Intel International Science and Engineering Fair participants received scholarships and prizes for their groundbreaking work. Intel awards included 19 “Best of Category” winners who each received a $5,000 Intel scholarship and a new laptop. In total, nearly $4 million is scholarships and awards were provided.

Top Ranked Engineering Blog

I ran across another site that ranks this blog first for engineering, which I always like – even if I realize the ranking is just one computation and hardly definitive.

Google returns this blog 3rd in search results. Yahoo also has us 3rd (behind 2 different blogs than Google show). We are the 5th results on live search. The ranking on Top 100 Engineering Blogs slipped to 7th (they eliminated the subscriber factor from the calculation, and that hurt our ranking). We are the number one ranked engineering blog on blogged.

Meeting the Challenge of Simplicity

Interesting webcast by Meeting the Challenge of Simplicity by Giles Colborne. This session addresses abstract notion of simplicity, looks at why it is critical in modern UI design and answers questions: Why does simplicity matter? Is there a meaningful definition of simplicity? Why do design processes and good intentions undermine simplicity? What processes and techniques can software developers use to achieve simplicity?

InfoQ is a great site for watching presentations online. With a simple but superior interface showing a live video with a separate area showing the current slides.

Friday Fun: Bird Using Bait to Fish

In the webcast an Aukuu bird (Black-crowned Night Heron) fishes using bread as bait. They normally hunt by waiting at the side of a lake and fishing. This individual learned how to bait the fish with bread and improve the fishing results. It also passed on that method to other birds that learned how to use the bait method themselves.

Another bird using bait (with turtles trying to get the bait) and another bird using bait (with a stork trying to steal the fish). And another one. The videos seem to be different species of birds to me.

Waste Treatment Plants Result in Super Bacteria

Multiple antibiotic-resistant bacteria has emerged as one of the top public health issues worldwide in the last few decades as the overuse of antibiotics and other factors have caused bacteria to become resistant to common drugs. Chuanwu Xi‘s group chose to study Acinetobacter because it is a growing cause of hospital-acquired infections and because of its ability to acquire antibiotic resistance.

Xi said the problem isn’t that treatment plants don’t do a good job of cleaning the water—it’s that they simply aren’t equipped to remove all antibiotics and other pharmaceuticals entering the treatment plants.

The treatment process is fertile ground for the creation of superbugs because it encourages bacteria to grow and break down the organic matter. However, the good bacteria grow and replicate along with the bad. In the confined space, bacteria share resistant genetic materials, and remaining antibiotics and other stressors may select multi-drug resistant bacteria.

While scientists learn more about so-called superbugs, patients can do their part by not insisting on antibiotics for ailments that antibiotics don’t treat, such as a common cold or the flu, Xi said. Also, instead of flushing unused drugs, they should be saved and disposed of at designated collection sites so they don’t enter the sewer system.

The next step, said Xi, is to see how far downstream the superbugs survive and try to understand the link between aquatic and human superbugs. This study did not look past 100 yards.

Xi’s colleagues include visiting scholar Yongli Zhang; Carl Marrs, associate professor of public health; and Carl Simon, professor of mathematics.

Xi and colleagues found that while the total number of bacteria left in the final discharge effluent declined dramatically after treatment, the remaining bacteria was significantly more likely to resist multiple antibiotics than bacteria in water samples upstream. Some strains resisted as many as seven of eight antibiotics tested. The bacteria in samples taken 100 yards downstream also were more likely to resist multiple drugs than bacteria upstream.

Full press release

Historical Engineering: Hanging Flume

photo of hanging flume overlook in Colorado, by John Hunter, Creative Commons Attribution.

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While driving from Dinosaur National Monument to Mesa Verde National Park last year I passed the sight above with the remnants of a hanging flume. The Montrose Placer Mining Company built a 13 mile canal and flume to deliver water from the San Miguel River for gold mining operations. The last 5 miles of the flume clung to the wall of the canyon itself, running along the cliff face in the photo above (see more photos).

Constructed between 1888 and 1891, the 4 foot deep 5 foot 4 inch wide hanging flume carried 23,640,000 gallons of water in a 24 hour period. The mining operations used water and sluice boxes to separate the gold from lighter materials (dirt and gravel).

The technology was not yet available to pump the water directly from the river at the necessary volume and pressure to wash the gold from the gravel, therefore they constructed the flume to transport the water.

The Great Sunflower Project

photo of sunflower (Helianthus Annuus Taiyo)

Sunflower photo from WikiMedia – Helianthus Annuus ‘Taiyo’

The Great Sunflower Project provides a way for you to engage in the ongoing study of bees and colony collapse disorder. The study uses the annual Lemon Queen sunflowers (Helianthus annuus), that can be grown in a pot on a deck or patio or in a garden (and they will send you seeds).

How do bees make fruits and vegetables?

Bees help flowers make seeds and fruits. Bees go to flowers in your garden to find pollen (the powder on the flower) and nectar which is a sweet liquid. Flowers are really just big signs advertising to bees that there is pollen or nectar available – though sometimes a flower will cheat and have nothing! The markings on a flower guide the bee right into where the pollen or nectar is.

All flowers have pollen. Bees gather pollen to feed their babies which start as eggs and then grow into larvae. It’s the larvae that eat the pollen. Bees use the nectar for energy. When a bee goes to a flower in your garden to get nectar or pollen, they usually pick up pollen from the male part of the flower which is called an anther. When they travel to the next flower looking for food, they move some of that pollen to the female part of the next plant which is called a stigma. Most flowers need pollen to make seeds and fruits.

After landing on the female part, the stigma, the pollen grows down the stigma until it finds an unfertilized seed which is called an ovary. Inside the ovary, a cell from the pollen joins up with cells from the ovary and a seed is born! For many of our garden plants, the only way for them to start a new plant is by growing from a seed Fruits are just the parts of the plants that have the seeds. Some fruits are what we think of as fruits when we are in the grocery store like apples and oranges. Other fruits are vegetables like tomatoes and cucumbers and peppers.