This paper was written by Meila (MIT) and Heckerman (Microsoft Research) and published at the Machine Learning journal in 2001.
This tech report compares three batch clustering algorithms: EM, CEM, and HAC and also investigate the effect of three different initialization schemes on the final solution produced by the EM algorithm.
The clustering algorithms first use the log posterior probability of model structure given the training data log P(K|Dtrain) to select model structure, and then learn the parameters of a given model structure. The EM algorithm is iterative, and in the E step, assigns the case fractionally to each cluster. The CEM algorithm assigns the case fully to the class k that has the highest posterior probability given the document and the current parameter values. The HAC algorithm merge smaller clusters by recursively merging the two clusters that are closest together until only K clusters are left. The authors derive the distance metric for mixtures of independent multinomially distributed variables.
The three initialization methods experimented are: the random approach where the parameters are independent of the data, the noisy-marginal method (data dependent), and the method of using HAC on a random sample of the data. Several performance criteria are used. For the model structure, the log-marginal-likelihood criterion and the difference between the number of clusters in the model and the true number of clusters are used. For the entire model, one criterion is the cross entropy between the true joint distribution for X and the joint distribution given by the model, and another criterion is the classification accuracy. Running time is also used to compare algorithms.
Experimental results from two datasets were reported. The synthetic dataset was constructed using the MSNBC news service, and the digits dataset consists of images of handwritten digits made available by the US Postal Service Office for Advanced Technology. For both datasets, EM outperformed CEM for all initialization methods and for all criteria (except that CEM is four times faster than EM). After constraining EM run time to match CEM, EM still performed better. When comparing EM versus HAC (initializing using Marginal method), EM is clearly better.
When comparing initialization methods, for the Synthetic dataset, Marginal and HAC are always better than Random (for all criteria) with no significant differences between themselves, but Marginal is much faster than HAC. For the digit6 dataset, there is no clear winner.
Picture of the Day:
First time ever a rescue helicopter landing in Bryce Canyon, Utah. The chopper landed right on the top of the ridge. Got to give the pilot some shout out for his awesome skills!
A voice came from outside the iron-door, “Mr. Ren, it has been very hot in the last couple of days. May I ask if the revered mister still enjoys his good health?”
As soon as Linghu Chong heard the voice, he recognized it instantly. It was the voice of Mr. Black-White. If he had come to his cell one month before, Linghu Chong would have shouted all kinds of invective at him with no scruples. However, after many days of imprisonment, his anger had mollified a great deal and he was able to think calmly.
“Why did he call me Mr. Ren? Has he come to the wrong cell?” he thought to himself and decided to remain silent and listen on.
“Every two months, I come and ask the revered mister the same question. Today is the first day of July, so please allow me to ask once again: Will the revered mister grant my request?” Mr. Black-White continued, his tone respectful and cautious.
Linghu Chong laughed inwardly. “He got the prison cells all mixed up and must have thought I am the Revered Mr. Ren. How careless of him!” But immediately after, he felt a chill in his heart. “Mr. Black-White obviously is the most meticulous one among the four Masters of the Plum Manor. It might be possible for Mr. Bald-Brush or Mr. Paint to mix up the prison cells, but how could Mr. Black-White actually make such a mistake? There must be a reason behind this.” With that in mind, he kept his silence.
Mr. Black-White continued, “Revered Mr. Ren, valiant and capable all your life, why let yourself languish with the decaying dust in the underground dungeon? My words are as firm as the mountain. If the revered mister grants me my request, I promise I will help the revered mister get out of this prison.”
Linghu Chong’s heart thumped wildly. Many thoughts raced through his mind, but he failed to put them in order. What was Mr. Black-White really after and why did he speak this way? He simply couldn’t figure it out. Then he heard Mr. Black-White asking a second time.
“Will the revered mister grant my request?”
Linghu Chong knew that this could be the very opportunity for him to escape. Despite any possible ill intentions, it would still have been a much better alternative than getting stranded forever in the underground prison for some unknown reasons. But having no way of identifying Mr. Black-White’s true intention, he bit his lip and remained silent, afraid that he might say something wrong to ruin this precious opportunity.
“Revered Mr. Ren, why aren’t you speaking up?” Mr. Black-White heaved a sigh. “Last time, when that boy Feng challenged you in the art of sword, you didn’t mention a single word about my request in front of my three sworn-brothers. I am truly grateful for the kindness. I thought to myself, the sword fight must have brought back the many fond memories and the lofty sentiments in Revered Mr. Ren’s heart, and reminded him of the vast world outside. If your Excellency could break out of the dark dungeon, the entire world would be yours for the taking, and you can snuff out any mundane life at will, whether male or female, old or young; and no one would ever dare defy your wish. Wouldn’t that be exhilarating? Granting the request would not have brought any nuisance to your own. Why wouldn’t you ever consent in the past twelve years?”
Linghu Chong could sense the sincerity in his voice. Apparently he really thought he was addressing senior master Ren, which puzzled Linghu Chong even more. He listened on as Mr. Black-White begged again and again for him to agree to the request. Linghu Chong really wanted to know more details about the request, but he reckoned that the situation would take an immediate bad turn if he opened his mouth. Holding his tongue forcibly with great effort, he dared not make the slightest sound.
“If the revered mister is still so stubborn, I guess I’ll visit him again in two months,” Mr. Black-White concluded. He suddenly let out a few chuckles. “The revered mister didn’t scold me this time. Maybe there’s a favorable turn in the situation. I hope the revered mister will give my request some good consideration in the next two months.” After those words, he turned around to exit.
Linghu Chong became quite worried. It would be another two months before Mr. Black-White would return, and how could he stand another two months of the miserable life in the pitch-black prison? He waited until Mr. Black-White had taken several steps and then spoke up in an intentionally lowered and coarse voice.
“What request shall I grant?”
Mr. Black-White turned around at once, and with a swift leap, he had returned back to the square-shaped opening.
“You will…you will grant me my request?” His voice trembled.
Linghu Chong turned to face the wall and covered his mouth with his hand.
“What request?” he said in a muffled voice.
“In the past twelve years, I would take on great risks to come here six times each year, just so that I could implore for the revered mister to consent. Why is the revered mister asking when the answer is so obvious?”
“I forgot!” Linghu Chong snorted.
“I would like the revered mister to teach me the secret of the magical art. Once I master the skills, I promise to let the revered mister out of this place.”
“Has he really mistaken me for that senior master Ren, or is this some kind of intrigue?” Linghu Chong pondered. Still having no clue about Mr. Black-White’s true intentions, he mumbled something indistinct, not even knowing what he said himself.
Naturally, Mr. Black-White didn’t understand a word of his, and had to ask again and again, “Will the revered mister grant it? Will the revered mister grant it?”
“You don’t live up to your promise. You won’t fool me,” Linghu Chong replied.
“What kind of guarantee would I have to provide so the revered mister will believe my words?”
“What do you have in mind?”
“I understand the revered mister’s worries. What if I break my promise after the revered mister teaches me the secret of the magical art and still not let him out? There is no need to worry! I have it all arranged, and the revered mister can put his trust in my arrangement,” Mr. Black-White answered.
“What arrangement?”
“Does this mean the revered mister will grant me my request?” Mr. Black-White asked quickly, his voice filled with excitement.
Linghu Chong thought very quickly, “He wants me to teach him the secret of the magical art. Where the heck would I find this secret of the magical art? But I might as well check out his arrangement. If he really will let me out of this place, I could just give him those meditation techniques carved on the steel plate. Who cares if it works or not, it doesn’t hurt to give him some false hope.”
When Mr. Black-White didn’t hear an answer, he added, “After the revered mister teaches me the magical art, I would have automatically become an apprentice of the revered mister. In our cult, an apprentice who deceives his master is to be skinned and dismembered alive. In the past several hundred years, not a single one had managed to get away from the harsh punishment. How would I ever dare to not let the revered mister out?”
“I see,” Linghu Chong let out another snort. “Come back in three days to get your answer.”
“Why won’t the revered mister grant my request today? Why wait another three days in this dark dungeon?” Mr. Black-White pleaded.
Linghu Chong thought to himself, “He is even more impatient than I am. It might be a good idea to wait three days and see if he’s going to pull some clever tricks.” At that thought, he produced a loud, disgruntled humph as if he was very annoyed.
“Sure! Sure! I shall return in three days so I could ask advice from the revered mister again!” Mr. Black-White hurriedly agreed.
Linghu Chong listened as Mr. Black-White walked out of the underground tunnel and closed the iron gate while many unsettling thoughts swirled inside his head.
“Could he really have mistaken me as the Ren-named senior master? He is a very meticulous man. How could he make such a silly mistake?”
Suddenly, an idea struck him. “Could it be possible that Mr. Huang-Zhong found out about Mr. Black-White’s visits and secretly moved senior master Ren to another cell, then put me in this cell instead? That’s got to be it! In the past twelve years, Mr. Black-White had been paying a visit every other month. It’s very likely that someone found out about it. It must have been Mr. Huang-Zhong who set up this scheme clandestinely.”
Then, he remembered what Mr. Black-White had said earlier. “In our cult, an apprentice who deceives his master is to be skinned and dismembered alive. In the past several hundred years, not a single one had managed to get away from the harsh punishment.”
“Our cult? Which cult?” he thought it over. “Could it be the Demon’s Cult? Is it possible that the senior master Ren and the Four Skunks of Jiangnan are all members of the Demon’s Cult? What kind of game are they playing? Why are they dragging me into this mess?”
As soon as the name “Demon’s Cult” came to his mind, he found the entire matter surreptitious and beyond his comprehension, and decided to not ponder upon it. Instead, he concentrated only on two things: “Was Mr. Black-White sincere or was he just acting it up? How shall I answer him when he comes back in three days?”
All kinds of strange idea went through his mind, but no matter how hard he tried, he still couldn’t figure out Mr. Black-White’s true intentions. After some time, he became extremely weary and fell asleep. By the time he woke up, his first thought was, “If brother Xiang were here, with his experience and knowledge, he would have guessed Mr. Black-White’s intention in no time. That Ren-named senior master was also very bright, likely even smarter than brother Xiang…oops!”
He suddenly cried out and jumped to his feet. After the nap, his brain functioned much better and he realized something.
“For the last twelve years, senior master Ren never granted him the request. Why? Because he knew very well what would happen if he did. As sharp and experienced as he is, he clearly knew the pros and cons of the matter.” Then he thought to himself, “Although senior master Ren should not grant the request, I am not senior master Ren. Why can’t I?”
He knew he shouldn’t do it. He could even smell the great danger involved, yet the hope of escape weighed heavily on his mind, and he would risk the greatest calamity just for an opportunity to break out from the dark underground dungeon. He soon made up his mind.
“When Mr. Black-White comes back in three days, I will consent to his request and teach him the inner energy cultivation and meditation techniques carved on the steel plate. Then I’ll just act according to his reactions.”
Now support the translator Lanny by following my blog and leaving comments! :)
Video of the Day:
One of the best fighting scenes in Kung Fu movies --- Jet Li's Fist of Legend
A few words first: To make it easier to find posts that interest you, I've added a search box to my blog (you probably have noticed it right above my post) that searches through all my blog posts but not anything outside of my blog. Just on the right side oft each post, you can also click on different blog labels to read my posts by category. At the end of each blog post, I've also included icons you can click to share the post with your friends using your favorite social network tools. Spread the good word if there's something you really enjoy! Okay, the real post starts below. ================================================================
Robot arm stabbing a human volunteer with a knife (Photo credit: IEEE Spectrum)
At the ICRA 2010 conference (IEEE International Conference on Robotics and Automation) that is currently ongoing in Anchorage, Alaska, some German researchers presented their latest research on the biomechanics of soft-tissue injury caused by a knife-wielding robot. The paper is titled "Soft-tissue Injury in Robotics." In other words, they wanted to find out what will happen if a robot holding a sharp knife erroneously stabs a person.And, no, I am not joking. The robot arm in the picture on the right is really holding a knife, and it really stabbed the guy's arm with it.
These researchers are from the Institute of Robotics and Mechatronics, part of DLR, the German aerospace agency, in Wessling, Germany, and they share the same dream with me --- that one day robots will be smart enough to take over kitchen duties and free us from the laborious duty of cooking. This task of course requires the robot to be able to handle a knife appropriately, so it can cut, chop, slide or dice during the course of preparing a meal. But what if it accidentally struck a human? With that question in mind, these researchers performed a series of experiment to investigate the severity of possible injuries and also designed a collision-detection to minimize the damage.
Various knives used in the experiments (Photo credit: IEEE Spectrum)
They mounted various sharp things, from knife to scissors to screwdriver (why does this somehow remind me of GTA San Andreas? Shudder!), to a DLR Lightweight Robot III, or LWRIII, a 7 degrees-of-freedom robot arm, and then tested the striking on a block of silicone, a pig's leg, and eventually, on the bare arm of a human volunteer. The collision-detection system turned out to be very successful, because the volunteer still has his arm.
The video below shows how the experiments were performed and how the robot arm performed differently with and without the collision-detection system (the real excitement is at the end of video). As a researching in Human-Robot Interaction myself, I couldn't help but imagine this poster in my head that reads, "Volunteer needed for a user study: Get Paid to be Stabbed by a Robot!"
But I am a little bit confused. Once turning on the collision-detection system, the robot will stop cutting/stabbing the human. The human is safe now, and so is that piece of steak! Three hours later, I'd be shouting in starved voice, "Where's my steak dinner?"
Note that the idea of a robot holding a knife would never be allowed in US universities. It would never get approval from the IRB (Institutional Review Board). See, we do things very differently here in the US, instead of knives, we give robots machine guns and missiles!! And there will be no danger to US citizens, because we send these robots to other countries! LOL!
MQ-9 Reaper Predator UAV
SWORD Robot
I think I am a bit off topic now, so let's get back to these German researchers. If I remember correctly, I actually saw a video from HRI 2007 made by the same guy demonstrating how he would let a powerful robot arm punch him in the head (Sorry I am having a hard time finding this video now). The robot arm would VERY QUICKLY slow down when it detects the collision, thus sparing the guy's life. Well, hats off to the guy!! Comparing to him, I am a coward, because I would never put myself under such conditions --- because I am a terrible programmer, and I have lots of bugs in my code. And my admiration for him went sky-high when I realized they also performed the following experiments. Ouch!!
Anyway, I think it will be a long time before we actually have knife-wielding robots that roam our homes. When I program my robots, I actually intentionally make it not touch things such as knives, gas stoves, and explosives. But I bet you this day will eventually come, and a lot of lawyers are going to get rich.
Drinking excessive amount of Mountain Dew and staying up till 4am can lead to severe stomach cramping and internal bleeding and many days of lost productivity.
If you've ever made purchases online, or signed up for any kind of account on the Internet (forums, subscriptions, etc.), or installed software applications on your computer, then you must have seen screens where you have to agree to some kind of terms and conditions, or EULA (standing for End User License Agreement). How many times, however, do you actually read through those pages after pages of dry, dull, impossible to understand legal languages, especially on a computer screen?
Well, if quickly clicking through things has grown into a habit for you, it's probably time to reconsider it now.
According to this article from Newslite and this article from geeks.com, GameStation, on UK online games retailer, added the "immortal soul clause" to its online purchase agreement basically saying the customers would grant them the right to claim their souls. More than 7,500 customers (88%) agreed to the clause without really reading the agreement details, and now GameStation legally owns thousands of souls. Here below are the exact wording of the sneaky clause:
By placing an order via this Web site on the first day of the fourth month of the year 2010 Anno Domini, you agree to grant Us a non transferable option to claim, for now and for ever more, your immortal soul. Should We wish to exercise this option, you agree to surrender your immortal soul, and any claim you may have on it, within 5 (five) working days of receiving written notification from gamesation.co.uk or one of its duly authorised minions. We reserve the right to serve such notice in 6 (six) foot high letters of fire, however we can accept no liability for any loss or damage caused by such an act.
If you a) do not believe you have an immortal soul, b) have already given it to another party, or c) do not wish to grant Us such a license, please click the link below to nullify this sub-clause and proceed with your transaction.
Luckily, 12% of the customers did notice a small tick box at the bottom of agreement allowing them to opt out of the clause, and earned themselves a £5 gift voucher by doing so. But really, how many of the 12% customers actually read the terms and services agreement? My guess would be very few.
Although this probably was part of an April Fool's Day joke (the vouchers were no joke), and GameStation has no intention to ever claim their rights on the souls (in fact, they emailed all customers nullifying the clause), this clearly shows the general public opinion on these agreements. Most people think that if most people don't read these things, they are no longer valid. However, the truth is that they will most likely be legally binding (not the soul clause, of course) unless challenged in a court of law. And do you ever want to get into a legal battle with large companies who employ an army of lawyers?
There are, actually, some people who take these agreements very "seriously!" Anne Loucks from obesso.com created a clever way to get herself out of legal troubles with EULAs. Using a piece of cardboard that reads "Kitty Agrees" with a protruding piece underneath, she would have her cat to step on the board, which pushes the spacebar underneath and agrees to an EULA for her. So worst comes to worst, it would be the cat losing its soul, and not Anne!
Putting aside the legality of these actions of both the businesses and users, clearly the system is not working very well. I know for regular business contracts or terms and agreements, critical elements are required by law to really stand out (bold, larger size, etc.). I am sure a better standard and approach will have to be created soon, because soon or later, somebody is getting sued over this.
Picture of the Day:
Brian Ghidinelli's creative reuse of his old equipments.
This paper is written by Steinback, Karpis, and Kumar, University of Minnesota, published at KDD workshop on text mining, 2000.
This paper presents the results of an experimental study of two main approaches to document clustering, agglomerative hierarchical clustering and K-means (standard K-means and bisecting K-means).
Example of Hierarchical Agglomerative Clustering (HAC)
The two basic approaches to generating a hierarchical clustering are agglomerative and divisive. The paper evaluated agglomerative techniques in the comparison. It then described the agglomerative clustering algorithm, the K-means algorithm, and the bisecting K-means algorithm in details.
Visualization of the K-means algorithm
Three evaluation metrics are used in the experiments, and they include two external quality measure, entropy, F measure, and one internal quality measure, overall similarity. The paper described each measure in detail.
Eight data sets were used in the experiments: 5 from TREC, 2 from Reuters-21578, and 1 from WebACE. Performances of three agglomerative hierarchical techniques, Intra-Cluster Similarity Technique (IST), Centroid Similarity Technique (CST), and UPGMA were compared using F-measure and entropy. UPGMA is the best performing hierarchical technique overall, therefore, its performance is compared against standard K-means and bisecting K-means. The performances of bisecting K-means with refinement and hierarchical with refinement are also included in the comparison. In the experiments, the authors used many runs of the regular K-means algorithm and also used incremental updating of centroids.
Experimental results show that the bisecting K-means technique is better than the standard K-means approach and as good or better than the hierarchical approaches when using the three evaluation metrics mentioned. Also the time complexity of bisecting K-means is linear, which makes it very attractive.
The authors argued that the agglomerative hierarchical clustering didn’t do well because nearest neighbors of documents often belong to different classes. K-means and bisecting K-means algorithms do better because they rely on a more global approach. They also believe that bisecting K-means does better than standard K-means because it produces relatively uniformly sized clusters.
Video of the Day:
The Honest $10000 SPAM
Even though miracle happens, still, don't click on suspicious links or give out your bank information. The Nigerian connection at the end of the video is simply hilarious!!
Volume One: The City by the Sea
-- written by Maoni
Chapter 5: Staggering Pillow
Although Fan Xian had
the body of a four-year-old, inside he had the soul of a mature person. The
bloodshed and massacre on his first day in this world left deep imprints in his
mind. For that reason, he always felt a sense of unease in his heart, knowing
that his mysterious pedigree would one day bring serious trouble to him.
Trouble had
finally found him today.
Since his sneak
attack ended in vain, it was no good to repeat the old trick. While sobbing
pitifully with the intent to baffle the late night visitor, Fan Xian worked his
brain hard for a method of escape.
“If I cry for
help, the man would surely kill me in no time. But the visitor is not moving. He
must be really confused when I randomly called him ‘Daddy’,” he thought to
himself.
“Daddy, Daddy…,”
he immediately cried out, taking full advantage of his very young age.
“Stop pretending,
Young Master Fan,” the man said in an indifferent tone. “You are really smart.
Even at such a young age, you already know how to protect yourself. But you
probably also know very well that I am not the Count, his Excellency.”
After these words,
the man tightened his grip of the dagger and then approached forward toward the
four-year-old Fan Xian.
Fan Xian kept the
innocent look and teams streamed down his face, but he felt a strong throb in
his chest.
“Then who are you,
uncle?” he said with a sob.
“Your father sent
me to check on you. So don’t scream, okay?”
The late night
visitor’s two eyes both had small tints of brown and looked somewhat ugly. The
crinkles by the corners of his eyes clearly gave away his age. The tone of his
words directly reminded Fan Xian of a pervert grandpa who invites little girls
to go watch goldfish with him[1].
Fan Xian did not
reveal any of those thoughts and still put out a flawless act of a
four-year-old kid, showing a bit of fright, a bit of surprise, and a little annoyance.
“You are not
Daddy!”
Then as though he
had not seen the dagger in the man’s hand, he turned his tiny buttocks and
climbed up the big bed.
“I don’t even know
what Daddy looks like,” he muttered.
The man walked
toward the bedside with a sinister smile. All of a sudden, the little boy on
the bed turned his head around and gazed in the direction behind the man with
sheer joy. “Mommy!” he called out.
……
……
This was a very
clumsy attempt to trick someone. If it were done by any other person, the man
would not have fallen for it. He was, after all, a great master who owned an
entire laboratory in the Capital City.
However, since it
was done by a four-year-old boy, the man simply believed in him, and as soon as
he heard Fan Xian’s calling for Mommy, his eyes opened wide in shock, and he
jerked his head around and looked over his shoulder.
Naturally, behind
him were only the tightly-shut door and the dense shade of the night.
“Wham!” a brittle
cracking sound suddenly resonated in the bedroom. The late night visitor
collapsed to the floor, blood all over his head.
Holding the
remaining half of the porcelain “pillow” in his hands, Fan Xian looked at the
man lying on the floor, heart still fluttering with fear. He felt the weight of
the remaining “pillow” and then clenched his teeth. Raising his arms high, he swung
the porcelain headrest at the back of the man’s head with all his might.
This time the
sound was somewhat muffled because of the strength carried. Even if this late
night visitor were a first-class master in martial arts, this staggering “pillow”
blow would have kept him unconscious for a good while.
……
……
“Is everything
alright?” The servant girl’s voice arose from the outside.
“Everything is
fine, Sis! I broke a tea cup. You can clean it up tomorrow.”
“I better clean it
up today. You might step on the broken pieces and hurt your feet.”
“You can do it
tomorrow!”
When the servant
girl recognized the unusual bad temper in the voice of the always gentle and
lovely Young Master, she held her tongue and said nothing.
Fang Xian walked
by the closet and pulled out a quilt used in the winter. Holding tight onto the
quilt cover, he ripped hard and made himself some cloth strips. Twisting the
cloth strips together, he tied up the unconscious man on the floor firmly. Only
by then, he noticed that the clothes on his back had been soaked by cold sweat.
Fear quickly
welled up in his heart – both in his previous life and the present life, this
was the first time he ever tried to kill someone, even though he was still
unsure if he did kill the man or not.
“That was too
risky,” he thought, “if the man was indeed a Kung Fu master, my first strike
would for sure have gotten me killed.”
He reached
underneath the cloth mask of the man and felt. The man was still breathing. For
some unknown reason, Fan Xian suddenly felt a strong urge to kill the man. A cold
shudder awoke him. He suddenly realized that ever since his rebirth, he seemed
to have morphed into someone much more firm and resolute. He didn’t even
hesitate for a second when he ruthlessly attacked the man.
He didn’t realize
that deep inside the heart of the child named Fan Xian, he considered himself as
someone who had already died once. Therefore, the new life in this world was
especially precious to him, and he would not allow anyone to take it away from
him.
As the old saying goes,
“You never know what you have until you lose it.” The truth was just that
simple.
Fan Xian held the
dagger in his hand and pondered over and over. In the end he still couldn’t
make himself kill the unconscious man on the floor. Suddenly he thought of
someone and a smile crept up his face.
Silently pushing the door open, he ran to the back court and crawled out from a
hole in the wall used by dogs to get in and out. Soon he was standing outside
of the small grocery store on the street corner right across from the Count’s
Manor.
……
……
“Thump! Thump!” he gently knocked on the
door of the small grocery store. The sounds were very light and didn’t travel
far even in the quiet night of Port Danzhou. But Fan Xian knew that the man
inside would hear the knock with no problem. Even though the man always
pretended to not know him for the last four years, at the critical moment, this
man was the only person in this world Fan Xian could trust.
“Who is it?”
A flat, emotionless voice came from inside
the grocery store.
“He hasn’t changed at all,” Fan Xian
thought, “just like that year outside of the Capital City, following a
prescribed pattern in both his speaking and his acts.” He rolled his eyes and
then replied softly, “I am Fan Xian.”
As expected, the wooden door of the grocery
store opened quietly, and the blind youngster stood at the doorway like a
ghost, which actually caught Fan Xian by surprise.
Fan Xian stared at
the man who sent him to Port Danzhou and the face and the black cloth covering
his eyes, which didn’t seem to have changed even the slightest bit. He couldn’t
help wondering, “Doesn’t this man ever get old?”
[1]
“Inviting little girls to go watch goldfish” is a popular phrase used in China
to refer to pervert child molesters.
Now support the author Maoni by clicking this link, and support the translator Lanny by following my blog and leaving comments! :)
Video of the Day:
Got an iPhone? Got a blender? Ever wondered if your iPhone would blend in your blender? Well, find out from this video! The funny thing is that every Saturday, I play soccer right across the street from this company called Blendtec!
Not too long ago, we talked about Geminoid, Dr. Ishiguro's "twin brother" robot in a previous post. That robot was built in 2006. Four years later in April 2010, Dr. Ishiguro unveiled his latest creation: a female andriod named Geminoid-F (F stands for female), built after an unnamed female model in her 20s (photo credit Yoshikazu Tsuno/AFP), according to this article at IEEE Spectrum.
The female robot is really the product of joint effort among Osaka University, ATR Laboratory, and Kokoro Co., a small Japanese firm specializing in building androids. Compared to the old male model, this new, more advanced model have the following improvements:
It can exhibit facial expressions much more naturally.
It only has 12 actuators (male model had 50)
Air servo valves and the control system are not embedded into the robot's body, and there is only a small external compressor (male model had a large external box for compressors and valves.)
The tele-operation system is using facial recognition software, so the operator doesn't have to wear any sensor at all.
Similar to it's male predecessor, Geminoid-F cannot walk and only have limited movements with its arms and legs. Most of the actuators are located around the neck and face. The main purpose of the robot is for tele-presence where an operator would be sitting in front of a camera and the robot would mimic the person's facial expression and lip/neck movements. One possible application of the robot is to support remote companionship. Dr. Ishiguro plans to test the robot in hospitals.
With a price tag of US $110,000 per copy, such a robot might not be very attractive to consumers even for people who seriously long for a twin brother or sister. However, the research team at least accomplished two things:
advanced the technology of natural expression for a robot, and
generated ample interest from the public to pay more attention to robotics technology
That leaves me with only one question: Who is he going to duplicate next time?
Picture of the Day:
Adeline will have a dance recital tomorrow. But she just lost a tooth the first time ever in her life! So here I present you:
Osaka, Japan is a the second largest city in Japan with over 20 million people and the commercial capital. It was also the base for Toyotomi Hideyoshia in his successful unification of Japan during the sixteenth century. Different functions and roles resulted in a city that mixes modern technology with historical heritages, making Osaka into a unique city where traditional culture thrived side-by-side along present day life style. Here you can find skyscrapers (e.g., Business Innovation Center Osaka, where HRI 2010 conference was held at) alongside sixteenth century castles (e.g., Osaka Castle right in the middle of the city), and highly sophisticated robots (e.g., D+ ropop robot, designed and made in Osaka) together with women wearing the traditional Japanese clothing, Kimono, waiting at the subway station.
Left: Business Innovation Center Osaka. Right: Osaka Castle in the middle of the city
Left: D+ ropop robot representing modern beauty and advanced technology. Right: Woman in traditional Kimono waiting at the subway station.
During our visit, we stayed at the City Plaza Osaka hotel (left below) right at the heart of downtown, where we can see the crowded city landscape right from the hotel window (right below). The building has a very modern look from the outside. However, the oval shaped top portion actually contained traditional Japanese spa, where people would bath together completely naked (they do separate men from women).
Left: City Plaze Osaka Hotel. Right: City landscape view from our hotel room.
Due to our busy schedule, we only had half a day to look around the city before we fly back to the US, so in the morning, I was forced to take on the Japanese subway system all by myself so I could complete the mission of getting wife some famous Japanese cosmetics. I had two hours to do it, and I pulled it off even though I almost got on a train going the opposite direction and had to run in pouring rain in random directions.
Left: People riding subway train on a Saturday morning. Right: Street view of downtown Osaka.
Left: Saturday shoppers at the shopping district. Middle: people enjoying traditional Japanese food (in the cylinder). Right: Female customers shopping for Kimono.
Left: Cosmetics store. Right: Sushi shop along the street.
Later in the morning, we visited the famous Osaka Castle. Since the castle is located right in the middle of the city, we simply walked over. It was raining at the time, but that didn't stop us from a nice spring field trip. The ancient looking castle with a moat surrounding it was right next to the very modern looking Osaka City Museum, making a very sharp visual contrast.
Left: Osaka City Museum right across the street from, Right: Moat of the Osaka Castle
Students making spring field trips on Saturday. Left: Elementary school kids heading to unknown location at the subway station. Right: Middle school students visiting the Osaka Castle
The Osaka Castle park covers approximately 15 acres of ground. Due to limited time (and we really didn't want to miss our plane), we walked straight to the main building in the castle and then walked straight back to the hotel. I wish we could have spared a bit more time because there were already beautiful cherry blossoms in other parts of the park.
Looking at city landscape from the top of the Osaka Castle (can you see the cherry blossoms?)
The main castle has turned into a museum showing many historical artifacts and documents dating back to the sixteenth century. Most levels of the building prohibited photographing, so I don't really have a lot to show you here except the two below.
Left: Miniature figures depicting an ancient battle. Right: Battle helmets wore by ancient war lords.
It was quite fortunate that such a famous historical site is within walking distance from our hotel, so we were actually able to see traditional and historical sites during the trip. I hope one day I can bring my family to visit the beautiful city again, so wife can go shop for cosmetics while I do real sightseeing. :)
This paper was written by Thorsten Joachims from University Dortmund. It was published at ECML-98 10th European Conference on Machine Learning. It has been cited by 3632 people according to Google Scholar. Very influential paper indeed!
This paper provides both theoretical and empirical evidence that SVMs are great for text categorization.
When performing text classification, the first step is to transform documents. Each distinct word becomes a feature and the frequency of the word in the document is the value of the feature, resulting in a very high-dimensional feature space. Then, the information gain criterion can be used to select a subset of features. The final step is to scale the dimensions of the feature vector with their inverse document frequency.
SVMs are very universal learners. It can learn linear threshold function and can also learn non-linear functions by using the kernel trick. One great property of SVMs is the ability to learn which is independent of the dimensionality of the feature space, because SVMs use support vectors. SVMs also do not require parameter tuning.
Left: Group of dots in different colors on 2D plane. Right: Boundaries identified using SVM to group colored dots.
SVMs work well for text categorization because of these following properties of text: 1) High dimensional input space. SVMs do not depend on the number of features and only use support vectors. This prevents overfitting. 2) Few irrelevant features. Aggressive feature selection may result in loss of information. SVMs can work with very high dimensional feature space. 3) Document vectors are sparse. SVMs work well with problems with dense concepts and sparse instances. 4) Most text categorization problems are linearly separable. These are the theoretical evidence.
The paper used two test collections: the “ModApte” split of the Reuters-21578 database and Ohsumed corpus. SVMs are compared with Naïve Bayes, Rocchio, kNN, and C4.5 Decision Tree. Precision/Recall-Breakeven Point is used as a measure of performance. Experimental results show that SVMs had robust performance improvements over other algorithms. Training using SVMs is slow but classification is very fast. SVMs eliminate the need for feature selection and do not require any parameter tuning.
Video of the Day:
I am not a member of the Mormon church, but I still found this story very moving. It was told by the former LDS Church President Gordon Hinckley. Hope you enjoy it! And may God bless us all if there is a God.
Two days from today, and between April 22 and 24, the 2009-2010 VEX Robotics Competition World Championship will be held at Dallas Conventional Center where over 3000 contestants from 14 countries around the world will meet and fight their guts out (correction, fight their robots' guts out).
It is interesting that I only heard about this competition a few days ago from my wife because she is actually working on arranging hotel and travel for the Chinese team. Therefore, I looked it up and hence, today's blog post. :)
The main sponsor of the competition is a company called Vex Robotics Design System, who makes and sells robotics kits to hobbyists and young students. At the beginning of the season each year, the organizer would announce a new challenge, and students around the world can then form teams to compete in this world-wide competition using robots built from, of course, the VEX robotics kit. Contestants contained mostly middle school and high school students. However, even elementary school students can compete in this competition. These teams then compete against each other at the local and regional level until finalists are determined who then compete in the world championship. The competition is presently in its third season. The challenge for the 2008-2009 season is called Elevation Challenge, and the new one for the 2009-2010 season is called Clean Sweep Challenge.
The video below is from last year's world championship, also held at Dallas Conventional Center.
This year's challenge is the clean sweep challenge where two teams, each team using two robots, are divided into two courts, and the goal is to rack up as many points in a fixed time by pushing, shoveling, throwing, and dumping balls out of the team's own court and into the opponent's court. In the first 20 seconds of the game, the robots will play autonomously by running programs written by the contestants. For the remaining duration of the game, each robot is teleoperated using a remote control by contestants. Each team is free to design the robots anyway they like, and the only constraint is that the size of each robot can not exceed a certain limit (read the detailed description of the rules). The video below is the game animation describing the game in detail.
Since each team has to fight all the way from local to international, there are plenty of videos of games played at different cities and regions. The video below shows a game played by team number 8888 from La Salle High School in the semifinals (probably at the country level). You can probably see that during the first 20 seconds, the robots looked very dumb and didn't really do much. This is probably due to the difficulty for pre-college-level students to master and implement advanced AI algorithms and techniques. However, the students still have to put in a lot of effort designing and implementing these robots from an mechanical engineering perspective. Still though, it would be so nice if we see people designing fully autonomous robots (or robots with supervisory control) to compete in such interesting games.
I wish all the contestants the best luck in the upcoming world competition. I am sure they will all have a ton of fun and hopefully many of them will grow up into sincere robotists.
