Tuesday, July 14, 2009

Military Developing Robot-Insect Cyborgs



Instead of creating robots, researchers hope to augment actual insects

Instead of attempting to create miniature robots as spies, researchers are now experimenting with developing insect cyborgs or "cybugs" that could work even better. So far scientists can already control the flight of moths using implanted devices.

Miniature robots could be good spies, but researchers now are experimenting with insect cyborgs or "cybugs" that could work even better.

Scientists can already control the flight of real moths using implanted devices.

The military and spy world no doubt would love tiny, live camera-wielding versions of Predator drones that could fly undetected into places where no human could ever go to snoop on the enemy. Developing such robots has proven a challenge so far, with one major hurdle being inventing an energy source for the droids that is both low weight and high power. Still, evidence that such machines are possible is ample in nature in the form of insects, which convert biological energy into flight.


It makes sense to pattern robots after insects — after all, they must be doing something right, seeing as they are the most successful animals on the planet, comprising roughly 75 percent of all animal species known to humanity. Indeed, scientists have patterned robots after insects and other animals for decades — to mimic cockroach wall-crawling, for instance, or the grasshopper's leap.

Mechanical metamorphosis
Instead of attempting to create sophisticated robots that imitate the complexity in the insect form that required millions of years of evolution to achieve, scientists now essentially want to hijack bugs for use as robots.

Originally researchers sought to control insects by gluing machinery onto their backs, but such links were not always reliable. To overcome this hurdle, the Hybrid Insect Micro-Electro-Mechanical Systems program is sponsoring research into surgically implanting microchips straight into insects as they grow, intertwining their nerves and muscles with circuitry that can then steer the critters. As expensive as these devices might be to manufacture and embed in the bugs, they could still prove cheaper than building miniature robots from scratch.

As these cyborgs heal from their surgery while they naturally metamorphose from one developmental stage to the next — for instance, from caterpillar to butterfly — the result would yield a more reliable connection between the devices and the insects, the thinking goes. The fact that insects are immobile during some of these stages — for instance, when they are metamorphosing in cocoons — means they can be manipulated far more easily than if they were actively wriggling, meaning that devices could be implanted with assembly-line routine, significantly lowering costs.

The HI-MEMS program at the U.S. Defense Advanced Research Projects Agency has to date invested $12 million into research since it began in 2006. It currently supports these cybug projects:

* Roaches at Texas A&M.
* Horned beetles at University of Michigan and the University of California at Berkeley.
* Moths at an MIT-led team, and another moth project at the Boyce Thompson Institute for Plant Research.

Success with moths
So far researchers have successfully embedded MEMS into developing insects, and living adult insects have emerged with the embedded systems intact, a DARPA spokesperson told LiveScience. Researchers have also demonstrated that such devices can indeed control the flight of moths, albeit when they are tethered.

To power the devices, instead of relying on batteries, the hope is to convert the heat and mechanical energy the insect generates as it moves into electricity. The insects themselves could be optimized to generate electricity.

When the researchers can properly control the insects using the embedded devices, the cybugs might then enter the field, equipped with cameras, microphones and other sensors to help them spy on targets or sniff out explosives. Although insects do not always live very long in the wild, the cyborgs' lives could be prolonged by attaching devices that feed them.

More details here...

Miniature Robot Crawls Through Veins



The Technion - Israel Institute of Technology has unveiled a miniature crawling robot (ViRob) that measures just 1 mm in diameter and 14 mm in length. The ViRob has the potential to perform precise medical procedures inside the human body in order to diagnose and potentially treat artery blockage and cancer.

The Technion researchers, led by Professor Moshe Shoham, Head of the Kahn Medical Robotics Laboratory, have developed a basic prototype of the robot, which can move as fast as 9 mm per second.

Using tiny arms which allow it to withstand blood pressure, it can crawl through the inner walls of blood vessels, the digestive tract and the respiratory system in order to progress through veins and arteries. The robot is powered by an external magnetic field allowing it to be controlled for an unlimited amount of time during medical procedures.

The team at the Technion is examining the possibility of using the ViRob as a treatment for lung cancer. ViRob could assist in targeted drug delivery to lung tumours as well as take samples from different areas within the body.

In addition, a number of these micro robots could simultaneously treat a variety of metastases. Researchers also plan to install additional equipment on the robot, including electrodes, miniature drug capsule and other miniature equipment.

Prof. Moshe Shoham said, “This robot is a breakthrough in the biomedical industry, as it allows doctors to access inaccessible areas in the body with minimal invasion. The technology enables a targeted treatment without scattering materials to unnecessary areas in the body."

Military Robot Could Feed on Dead Bodies





It could be a combination of 19th-century mechanics, 21st-century technology — and a 20th-century horror movie.

A Maryland company under contract to the Pentagon is working on a steam-powered robot that would fuel itself by gobbling up whatever organic material it can find — grass, wood, old furniture, even dead bodies.

Robotic Technology Inc.'s Energetically Autonomous Tactical Robot — that's right, "EATR" — "can find, ingest, and extract energy from biomass in the environment (and other organically-based energy sources), as well as use conventional and alternative fuels (such as gasoline, heavy fuel, kerosene, diesel, propane, coal, cooking oil, and solar) when suitable," reads the company's Web site.

That "biomass" and "other organically-based energy sources" wouldn't necessarily be limited to plant material — animal and human corpses contain plenty of energy, and they'd be plentiful in a war zone.

EATR will be powered by the Waste Heat Engine developed by Cyclone Power Technology of Pompano Beach, Fla., which uses an "external combustion chamber" burning up fuel to heat up water in a closed loop, generating electricity.

The advantages to the military are that the robot would be extremely flexible in fuel sources and could roam on its own for months, even years, without having to be refueled or serviced.

Upon the EATR platform, the Pentagon could build all sorts of things — a transport, an ambulance, a communications center, even a mobile gunship.


In press materials, Robotic Technology presents EATR as an essentially benign artificial creature that fills its belly through "foraging," despite the obvious military purpose.

Japanese Scientists's Robot-Insects



Police release a swarm of robot-moths to sniff out a distant drug stash. Rescue robot-bees dodge through earthquake rubble to find survivors.

These may sound like science-fiction scenarios, but they are the visions of Japanese scientists who hope to understand and then rebuild the brains of insects and programme them for specific tasks.

Ryohei Kanzaki, a professor at Tokyo University's Research Centre for Advanced Science and Technology, has studied insect brains for three decades and become a pioneer in the field of insect-machine hybrids.

His original and ultimate goal is to understand human brains and restore connections damaged by diseases and accidents -- but to get there he has taken a very close look at insects' "micro-brains".

The human brain has about 100 billion neurons, or nerve cells, that transmit signals and prompt the body to react to stimuli. Insects have far fewer, about 100,000 inside the two-millimetre-wide (0.08 inch) brain of a silkmoth.

But size isn't everything, as Kanzaki points out.

Insects' tiny brains can control complex aerobatics such as catching another bug while flying, proof that they are "an excellent bundle of software" finely honed by hundreds of millions of years of evolution, he said.

For example, male silkmoths can track down females from more than a kilometre (half a mile) away by sensing their odour, or pheromone.

Kanzaki hopes to artificially recreate insect brains.

"Supposing a brain is a jigsaw-puzzle picture, we would be able to reproduce the whole picture if we knew how each piece is shaped and where it should go," he told AFP.

"It will be possible to recreate an insect brain with electronic circuits in the future. This would lead to controlling a real brain by modifying its circuits," he said.

Kanzaki's team has already made some progress on this front.

In an example of 'rewriting' insect brain circuits, Kanzaki's team has succeeded in genetically modifying a male silkmoth so that it reacts to light instead of odour, or to the odour of a different kind of moth.

Such modifications could pave the way to creating a robo-bug which could in future sense illegal drugs several kilometres away, as well as landmines, people buried under rubble, or toxic gas, the professor said.

All this may appear very futuristic -- but then so do the insect-robot hybrid machines the team has been working on since the 1990s.

In one experiment, a live male moth is strapped onto what looks like a battery-driven toy car, its back glued securely to the frame while its legs move across a free-spinning ball.

Researchers motivate the insect to turn left or right by using female odour.

The team found that the moth can steer the car and quickly adapt to changes in the way the vehicle operates -- for example by introducing a steering bias to the left or right similar to the effect of a flat tyre.

In another, more advanced, test, the team severed a moth's head and mounted it onto the front of a similar vehicle.

They then directed similar odour stimuli to the contraption which the insect's still-functioning antennae and brain picked up.

Researchers recorded the motor commands issued by nerve cells in the brain, which were transmitted to steer the vehicle in real time.

The researchers also observed which neuron responds to which stimulus, making them visible using fluorescent markers and 3-D imaging.

The team has so far obtained data on 1,200 neurons, one of the world's best collections on a single species.

Kanzaki said that animals, like humans, are proving to be highly adaptable to changing conditions and environments.

"Humans walk only at some five kilometres per hour but can drive a car that travels at 100 kilometres per hour. It's amazing that we can accelerate, brake and avoid obstacles in what originally seem like impossible conditions," he said.

"Our brain turns the car into an extension of our body," he said, adding that "an insect brain may be able to drive a car like we can. I think they have the potential.

"It isn't interesting to make a robo-worm that crawls as slowly as the real one. We want to design a machine which is far more powerful than the living body."

Copyright © 2009 AFP.

Office 2010 Coming To The Web For Free


In a move that will likely expand its market reach while adding appeal to its product range, American software behemoth Microsoft has this week confirmed upcoming free Web-based iterations of its popular Office productivity suite.

Specifically, next year’s official launch of Office 2010 will be boosted by the online availability of scaled back versions of Word, Excel, PowerPoint and OneNote.






Get Microsoft Silverlight



“We believe the web has a lot to offer in terms of connectivity,” a Microsoft product manager explained to the BBC.

“We have over half a billion customers world-wide and what we hear from them is that they really want the power of the web without compromise,” he added. “They want collaboration without compromise.”

According to Redmond-based Microsoft, more than 400 million customers armed with Windows Live accounts will receive online access to the free lightweight productivity applications.

A public beta period allowing for widespread testing and feedback collection regarding the free online Office suite is likely to be opened by the end of 2009.

In terms of the upcoming Office product range, Microsoft has said the new suite will be offered in five different editions – which is a reduction from the usual eight.

Monday, July 13, 2009

Windows Embedded @ Imagine Cup 2009


Solve the World's Toughest Problems

"I wish there had been an Imagine Cup when I was growing up. It gets people involved in seeing that software is changing the world."

- Bill Gates
Chairman, Microsoft Corp.

Everything that the world may become "someday" lies in the hands of young people today. As they look at the road ahead, their close relationship with technology enables them to dream in ways we never have before. Put the two together, and you have young minds holding the tools that can make their vision a reality.

This is the recipe that inspired Microsoft to create the Imagine Cup. What begins with a burst of inspiration and a lot of hard work can become a future software breakthrough, a future career, or a flourishing new industry. The Imagine Cup encourages young people to apply their imagination, their passion and their creativity to technology innovations that can make a difference in the world – today. Now in its eighth year, the Imagine Cup has grown to be a truly global competition focused on finding solutions to real world issues.

Open to students around the world, the Imagine Cup is a serious challenge that draws serious talent, and the competition is intense. The contest spans a year, beginning with local, regional and online contests whose winners go on to attend the global finals held in a different location every year. The intensity of the work brings students together, and motivates the competitors to give it their all. The bonds formed here often last well beyond the competition itself.

Following are the videos of Image Cup 2009 held in Cairo...

Windows Embedded @ Imagine Cup 2009 - Days 1




Windows Embedded @ Imagine Cup 2009 - Days 2



Windows Embedded @ Imagine Cup 2009 - Days 3



Windows Embedded @ Imagine Cup 2009 - Days 4



Windows Embedded @ Imagine Cup 2009 - Days 5




Get ready for Imagin Cup 2010 in Poland!



See more details here...


Sunday, July 12, 2009

Norton AntiVirus 2010 Preview



Norton AntiVirus 2010 will be the fastest and lightest malware scanner Symantec has ever delivered. Norton AntiVirus scans faster and uses less memory than any other antivirus product on the market. Unlike free solutions from Microsoft, Norton AntiVirus includes intrusion detection to detect malicious code hidden in web sites before it can strike.

Norton AntiVirus’s pulse updates ensure that you are always plugged into Symantec’s global security grid and you are never more than a few minutes away from the latest update.

Improved Norton Safe Web technology blocks Internet threats before they can infect your PC. So you can browse, buy and bank online with confidence. Plus, unlike other antivirus products, Norton AntiVirus 2010 provides easy-to-understand threat and performance information to help you avoid future threats and keep your PC running fast.

Note that you are required to register the product before download can commence.

Download here...

My Blog - Google Analaytic Report



Google Analytic is very handy tool to manage traffic on your website. Its easily integrable with any web page and very power tool to improve traffic on your website. Following is report for www.mrmubi.com for 12th July 2009.

Map Overlay:


Country/Territory
Visits
Pages/Visit
Avg. Time on Site
% New Visits
Bounce Rate
1. 134 1.81 00:03:37 2.24% 65.67%
2. 6 1.33 00:00:09 83.33% 66.67%
3. 6 1.50 00:03:23 16.67% 66.67%
4. 5 2.60 00:03:13 80.00% 60.00%
5. 5 1.00 00:00:00 100.00% 40.00%
6. 4 1.75 00:04:35 100.00% 75.00%
7. 3 1.33 00:00:29 100.00% 66.67%
8. 3 1.00 00:00:00 33.33% 0.00%
9. 2 1.50 00:00:57 50.00% 50.00%
10. 2 1.50 00:00:12 100.00% 50.00%
11. 2 1.00 00:00:00 100.00% 0.00%
12. 2 1.50 00:00:01 100.00% 50.00%
13. 2 1.00 00:00:00 100.00% 30.00%
14. 2 1.00 00:00:00 50.00% 20.00%
15. 1 1.00 00:00:00 100.00% 10.00%
16. 1 1.00 00:00:00 100.00% 10.00%
17. 1 1.00 00:00:00 100.00% 30.00%
18. 1 1.00 00:00:00 100.00% 20.00%
19. 1 9.00 00:48:16 100.00% 0.00%
20. 1 1.00 00:00:00 100.00% 0.00%


Network Locations:







Network Location
Visits
Pages/Visit
Avg. Time on Site
% New Visits
Bounce Rate
1. 75 2.01 00:03:57 2.67% 60.00%
2. 59 1.54 00:03:12 1.69% 72.88%
3. 5 1.60 00:04:03 0.00% 60.00%
4. 3 1.00 00:00:00 33.33% 100.00%
5. 2 1.50 00:00:57 50.00% 50.00%
6. 2 1.00 00:00:00 50.00% 0.00%
7. 2 1.00 00:00:00 50.00% 0.00%
8. 2 1.00 00:00:00 100.00% 20.00%
9. 2 1.00 00:00:00 50.00% 30.00%
10. 1 2.00 00:00:10 100.00% 0.00%
11. 1 1.00 00:00:00 100.00% 10.00%
12. 1 1.00 00:00:00 100.00% 10.00%
13. 1 1.00 00:00:00 100.00% 100.00%
14. 1 2.00 00:00:46 100.00% 0.00%
15. 1 8.00 00:14:50 100.00% 0.00%
16. 1 2.00 00:01:17 100.00% 0.00%
17. 1 1.00 00:00:00 100.00% 80.00%
18. 1 1.00 00:00:00 100.00% 100.00%
19. 1 1.00 00:00:00 100.00% 10.00%
20. 1 2.00 00:00:01 100.00% 0.00%
21. 1 1.00 00:00:00 100.00% 50.00%
22. 1 1.00 00:00:00 100.00% 10.00%
23. 1 1.00 00:00:00 100.00% 10.00%
24. 1 1.00 00:00:00 100.00% 40.00%
25. 1 2.00 00:00:23 100.00% 0.00%
26. 1 1.00 00:00:00 100.00% 30.00%
27. 1 1.00 00:00:00 100.00% 10.00%
28. 1 4.00 00:18:20 100.00% 0.00%
29. 1 2.00 00:01:26 100.00% 0.00%
30. 1 1.00 00:00:00 100.00% 10.00%
31. 1 1.00 00:00:00 100.00% 50.00%
32. 1 1.00 00:00:00 100.00% 30.00%
33. 1 1.00 00:00:00 100.00% 20.00%
34. 1 1.00 00:00:00 100.00% 30.00%
35. 1 1.00 00:00:00 100.00% 10.00%
36. 1 1.00 00:00:00 100.00% 20.00%
37. 1 9.00 00:48:16 100.00% 0.00%
38. 1 1.00 00:00:00 100.00% 50.00%
39. 1 1.00 00:00:00 100.00% 10.00%
40. 1 1.00 00:00:00 100.00% 10.00%
41. 1 1.00 00:00:00 100.00% 50.00%


Thanks you all for visiting my blog.

Stay tuned.

Japanese railway workers take 'Smile Scan' test


Keihin Electric Express Railway Co. has introduced a "Smile Scan" system to evaluate the grins of its station staff.

The smile-measuring software has been developed by Kyoto-based precision equipment maker Omron Corp. The device analyzes the facial characteristics of a person, including eye movements, lip curves and wrinkles, and rates a smile on a scale between 0 and 100 percent using a camera and computer.

For those with low scores, advice like "You still look too serious," or "Lift up your mouth corners," will be displayed on the screen.

Some 530 employees of the Tokyo-based railway company will check their smiles with Smile Scan before starting work each day. They will print out and carry around an image of their best smile in an attempt to remember it.

"We aim to improve our services to make our customers smile," says a company official.

Saturday, July 11, 2009

Identity Theft: Be Prepared


Reduce the info available about you in the public domain. Data you provide on the Net lasts forever and can assist someone in assuming your identity or targeting you for a crime. Keep personal info out of business profiles. Where you live, who you know, and what you do with spare time makes you an interesting person but an easy target.

Every time I watch the news, it seems a new frightening event is occurring. Swine flu, economy, identity theft and gun-carrying coworkers weren't things I used to worry about. How do you keep yourself safe in an increasingly chaotic world?

As I frequently tell my clients, I want you to be prepared, not just scared, about events you can't control.

I interviewed a security Relevant Products/Services specialist, Christopher Falkenberg, for tips on workplace safety. He's worked as a secret service agent and lawyer before starting Insite Security.

Falkenberg surprised me by pointing out that our risk for identity theft has gone down. He said the big problem now is identity impersonations. Apparently, Facebook and LinkedIn can be useful but dangerous because they can give the wrong people too much information.

I asked Falkenberg what he would advise readers to do. His hot tips included:

1. Reduce the information available about you in the public domain. Data you provide on the Internet lasts forever and can assist someone in assuming your identity or targeting you for a crime.

2. Keep personal information out of business profiles. Where you live, who you know, and what you do with spare time makes you an interesting person but an easy target.

3. Be wary of calls you get at work. Falkenberg said criminals are masters at pretending to be a close friend of someone they stalk. If in doubt, don't give out information about coworkers.

4. If a caller pressures you to cough up confidential corporate information, be suspicious. Falkenberg said con artists may use bits of information and pressure tactics to get what they want. Check out the identity of callers.

I was surprised to learn there's actually research on who survives a crisis. Turns out that pessimists fare better than optimists. Having a survival mindset means you have to imagine worst- case scenarios. If you're on a plane, have you counted the rows between you and the exit? If you're staying at a hotel, did you pay attention to the exit route? At work, have you asked about whether the organization has a plan for violence, disasters or pandemics?

Falkenberg said the biggest hurdle for people in a catastrophic event is not to freeze or act habitually. Did you know that most people in a plane crash actually slow themselves down by automatically getting their carry-on luggage?

Having more money or visibility actually increases your security risks (some comfort for the rest of us during this economy). Falkenberg recommends that those with higher income or visibility make certain they keep public information about them vague, business oriented and impersonal. He highlighted the need to do thorough background checks on anyone working for you.

[I] frequently point out that we can't avoid adversity but we can learn ways to handle it well. Falkenberg advises that denial is no protection against a crisis.

Go through your worst case scenarios, listen to your gut instincts, and don't ignore information that makes you uncomfortable.

Friday, July 10, 2009

NASA Launches Possible Astronaut Escape Vehicle


NASA successfully tested on Thursday an escape system for astronauts that may be used on the next generation of shuttle spacecraft.

The unpiloted Max Launch Abort System (MLAS) lifted off from a launch facility here just after sunrise and soared about a mile into the atmosphere before a mockup crew capsule separated from its bullet-shaped enclosure and parachuted safely to the ground.

The MLAS is being considered as an alternative means for astronauts to escape should trouble develop during or shortly after launch. It would eliminate the need for an escape launch tower, such as that used during the Apollo program, as well as attitude control engines.



The system is composed of four parts: a bullet-like fairing with four fins, the crew capsule, a motor cage, and "coast skirt" connecting the motor cage to the fairing. Weighing more than 46,000 pounds and more than 33 feet tall, the MLAS would sit atop an Ares I rocket. Should a problem occur during the early moments of launch, the motor of the MLAS would turn on, carrying the crew away from the rocket. The sections will separate and float to safety at the end of parachutes.


MLAS is not expected to replace an escape system already developed for Orion spacecraft, which will replace the space shuttle by 2012 as a means of traveling to the International Space Station and the moon.

--Wallops Island, VA (AHN)

Thursday, July 9, 2009

Robot Teaches Itself to Smile


A robot has taught itself to smile, frown, and make other human facial expressions using machine learning.

To get the incredibly realistic Einstein robot to make facial expressions, researchers used to have to program each of its 31 artificial muscles individually through trial and error. Now, computer scientists from the Machine Perception Laboratory at the University of California, San Diego have used machine learning to enable the robot to learn expressions on its own.

“The robotic approach is the ultimate in helping us understand learning and development,” said social development expert Daniel Messinger at the University of Miami, who was not involved with the Einstein research but collaborates with the group on another project. “There’s so much we can learn by actually trying to make it happen instead of just watching kids try to move their faces — it’s like having a baby as opposed to just watching a baby.”

According to the researchers, who presented the project last month at the 2009 IEEE 8th International Conference on Development and Learning, this is the first time anyone has used machine learning to teach a robot to make realistic facial expressions.

To begin teaching the robot, the researchers stuck Einstein in front of a mirror and instructed the robot to “body babble” by contorting its face into random positions. A video camera connected to facial recognition software gave the robot feedback: When it made a movement that resembled a “real” expression, it received a reward signal.

“It’s an iterative process,” said facial recognition expert Marian Bartlett, a co-author of the study. “It starts out completely random and then gets feedback. Next time the robot picks an expression, there’s a bias towards putting the motors in the right configuration.”

After the robot figured out the relationship between different muscle movements and known facial expressions, it started experimenting with new expressions, such as eyebrow narrowing.

The robot’s expressions are still a bit awkward, but the researchers say they’re working on ways to make them more realistic, as well experimenting with strategies besides “body babbling” that might speed up the learning process. The group says its studious robot may even improve our understanding of how infants and children learn to make facial expressions.

“The idea is to try to understand some of the computational principles behind learning,” Bartlett said. “Here the computational principle is reinforcement learning and active exploration, which may also be behind learning motor movements in an infant.”

The next step is to get the Einstein robot to start socializing. Once the robot can mimic facial expressions in a social context, the researchers plan to use him in an “automatic tutoring” experiment.

“We’re putting facial expressions onto the robot so that he can engage with a pupil in a non-verbal manner and approximate one-on-one human tutoring as much as possible,” Bartlett said. “Studies have shown that human one-on-one tutoring improves learning by as much as two standard deviations — we want to know how can you try to approximate that with robotic tutoring.”

How a Denial-of-Service Attack Works


Investigators are piecing together details about one of the most aggressive computer attacks in recent memory -- a powerful "denial-of-service" assault that overwhelmed computers at U.S. and South Korean government agencies, companies and institutions, in some cases for days.
How does this type of cyber attack work? And how can people make sure their computers are safe?
Here are some questions and answers about the attack.
Q: What is a "denial-of-service" attack?
A: Think about what would happen if you and all your friends called the same restaurant over and over and ordered things you didn't even really want. You'd jam the phone lines and overwhelm the kitchen to the point that it couldn't take any more new orders.
That's what happens to Web sites when criminals hit them with denial-of-service attacks. They're knocked offline by too many junk requests from computers controlled by the attackers.
The bad guys' main weapon in such an attack is "botnets," or networks of "zombie" personal computers they've infected with a virus. The virus lets the criminals remotely control innocent people's machines, which are programmed to contact certain Web sites over and over until that overwhelms the servers that host the sites. The servers become too busy to respond to anything, and the Web site slows or stops working altogether.
It's different from what usually happens when you try to access a Web site. Normally, you just make one request to see the site, and unless there's a crush of traffic from something like a big news event, the servers respond well. Hijacked PCs, on the other hand, are programmed to send way more traffic than a normal user could generate on his or her own.
Q: How often do these attacks happen?
A: People try denial-of-service attacks all the time -- many government and private sites report being hit every day. Often the assaults are unsuccessful, because Web sites have ways of identifying and intercepting malicious traffic. However, sites really want to avoid blocking legitimate Web users, so more often than not, Internet traffic is let through until a problem is spotted.
Denial-of-service attacks are noisy by design, and they intend to make a statement. They're not subtle attempts to infiltrate a Web site's defenses, which can be much more insidious because that gives hackers access to whatever confidential information is stored there.
Often the attacks take a site out for a few hours, before Web site administrators can respond. What made the most recent attack notable is that it was widespread and went on for a while, beginning over the July Fourth holiday weekend and running into this week. It's not yet clear how the attack was able to last that long.

Q: Some organizations appear to have fended off these recent attacks, while other Web sites went down. How can this be?
A: The sites that went down probably were less prepared, because they are less accustomed to being hit or aren't sensitive enough to warrant extra precautions.
Popular Web sites, like e-commerce and banking sites, have a lot of experience dealing with denial-of-service attacks, and they have sophisticated software designed to identify malicious traffic. Often that's done by flagging suspicious traffic flowing into the site, and if there's enough of it, preventing it from ever reaching the site's servers.
Another approach is to flag suspicious individual machines that seem to be behind an attack, and ban any traffic from them from reaching the site.
That can often be difficult, though, because criminals use "proxy" computers to route their traffic, masking the source of the original requests. Proxy computers are often other infected computers that are part of a botnet.
Q: Is there usually evidence of who the culprits were? Or is the nature of the attack such that it leaves few fingerprints?
A: It's usually easier to stop a denial-of-service attack than it is to figure out who's behind it. Simply identifying where the malicious traffic is coming from won't get investigators very far, since the infected PCs that get roped into a botnet are owned by innocent people who don't know their computers are being used for nefarious purposes.
Pat Peterson, a security researcher and fellow at Cisco Systems Inc., says sophisticated attackers have also been adding a more subtle approach to evade detection.
Instead of directing huge amounts of traffic at a target site, they'll make more complicated requests one at a time that eat up more of the site's computing power , like trying to log in using bogus usernames and passwords. If enough of those requests are made, on a site that requires a lot of computing power, the effect can be the same, and the site gets knocked out.
This type of attack is trickier because it doesn't involve the sort of massive traffic surge that would normally tip off network administrators. This advanced tactic wasn't necessarily used in the most recent attacks. In fact there are signs the attacks were relatively amateurish. The programming code appears to have been patched together largely from material that has been circulating in the criminal underground for several years, according to Jose Nazario, manager of security research for Arbor Networks.
Q: If these attacks make use of compromised computers corralled into a "botnet," should I be worried about whether my PC is one of them? What could I do to prevent that or fix it?
A: If your computer is being used in a denial-of-service attack, you're likely to see a significant slowdown, because your processing power is being siphoned for the assault. But there aren't always obvious signs that your computer has been infected.
So the best thing is to focus on prevention, namely by having up-to-date antivirus software. In particular, make sure your antivirus software gets updated over the next few days.
If you're concerned your machine might be infected, it's wise to run an antivirus scan. Many antivirus companies offer a free scan from their Web sites.