What is a "computer algorithm"?

To make a computer do anything, you have to write a computer program. To write a computer program, you have to tell the computer, step by step, exactly what you want it to do. The computer then "executes" the program, following each step mechanically, to accomplish the end goal.

When you are telling the computer what to do, you also get to choose how it's going to do it. That's where computer algorithms come in. The algorithm is the basic technique used to get the job done. Let's follow an example to help get an understanding of the algorithm concept.

Let's say that you have a friend arriving at the airport, and your friend needs to get from the airport to your house. Here are four different algorithms that you might give your friend for getting to your home:

The taxi algorithm:
Go to the taxi stand.
Get in a taxi.
Give the driver my address.
The call-me algorithm:
When your plane arrives, call my cell phone.
Meet me outside baggage claim.
The rent-a-car algorithm:
Take the shuttle to the rental car place.
Rent a car.
Follow the directions to get to my house.
The bus algorithm:
Outside baggage claim, catch bus number 70.
Transfer to bus 14 on Main Street.
Get off on Elm street.
Walk two blocks north to my house.
All four of these algorithms accomplish exactly the same goal, but each algorithm does it in completely different way. Each algorithm also has a different cost and a different travel time. Taking a taxi, for example, is probably the fastest way, but also the most expensive. Taking the bus is definitely less expensive, but a whole lot slower. You choose the algorithm based on the circumstances.
In computer programming, there are often many different ways -- algorithms -- to accomplish any given task. Each algorithm has advantages and disadvantages in different situations. Sorting is one place where a lot of research has been done, because computers spend a lot of time sorting lists. Here are five different algorithms that are used in sorting:

Bin sort
Merge sort
Bubble sort
Shell sort
Quicksort
If you have a million integer values between 1 and 10 and you need to sort them, the bin sort is the right algorithm to use. If you have a million book titles, the quicksort might be the best algorithm. By knowing the strengths and weaknesses of the different algorithms, you pick the best one for the task at hand.

harddisk

Hard Disk Basics
Hard disks were invented in the 1950s. They started as large disks up to 20 inches in diameter holding just a few megabytes. They were originally called "fixed disks" or "Winchesters" (a code name used for a popular IBM product). They later became known as "hard disks" to distinguish them from "floppy disks." Hard disks have a hard platter that holds the magnetic medium, as opposed to the flexible plastic film found in tapes and floppies.
At the simplest level, a hard disk is not that different from a cassette tape. Both hard disks and cassette tapes use the same magnetic recording techniques described in How Tape Recorders Work. Hard disks and cassette tapes also share the major benefits of magnetic storage -- the magnetic medium can be easily erased and rewritten, and it will "remember" the magnetic flux patterns stored onto the medium for many years.

In the next section, we'll talk about the main differences between casette tapes and hard disks.

intelliget virtuel agents

While we already deal with some virtual AI -- notably in action games against computer-controlled "bots" or challenging a computer opponent to chess -- the work of Novamente, Electric Sheep Company and other firms has the potential to initiate a new age of virtual AI, one where, for better or worse, humans and artificial intelligences could potentially be indistinguishable.

If you think about it, we take in numerous pieces of information just walking down the street, much of it unconsciously. You might be thinking about the weather, the pace of your steps, where to step next, the movement of other people, smells, sounds, the distance to the destination, the effect of the environment around you and so forth. An artificial intelligence in a virtual world has fewer of these variables to deal with because as of yet, no virtual world approaches the complexity of the real world. It may be that by simplifying the world in which the artificial intelligence operates (and by working in a self-contained world), some breakthroughs can be achieved. Such a process would allow for a more linear development of artificial intelligence rather than an attempt to immediately jump to lifelike robots capable of learning, reason and self-analysis.

Goertzel states that a virtual world also offers the advantage of allowing a newly formed artificial intelligence to interact with thousands of people and characters, increasing learning opportunities [source: PC World]. The virtual body is also easier to manage and control than that of a robot. If an AI-controlled parrot seems to have particular challenges in a game world, it's less difficult for programmers to create another virtual animal than if they were working with a robot. And while a virtual world AI lacks a physical body, it displays more complexity (and more realism) than a simple AI that merely carries on text-based conversations with a human.

Novamente claims that its system is the first to allow artificial intelligences to progress through a process of self-analysis and learning [source: Novamente]. The company hopes that its AI will also distinguish itself from other attempts at AI by surprising its creators in its capabilities -- for example, by learning a skill or task that it wasn't programmed to perform. Novamente has already created what it terms an "artificial baby" in the AGISim virtual world [source: Novamente]. This artificial baby has learned to perform some basic functions.

Despite all of this excitement, the AI discussed here are far from what's envisioned in "Terminator." It will be some time before AIs are seamlessly interacting with players, impressing us with their cleverness and autonomy and seeming all too human. Even Philip Rosedale, the founder of Linden Labs, the company behind "Second Life," has warned against becoming caught up in the hype of the supposedly groundbreaking potential of these virtual worlds [source: CNET News].

But "Second Life" and other virtual worlds may prove to be the most valuable testing grounds to date for AI. It will also be interesting to track how virtual artificial intelligences progress as the virtual worlds they occupy change and become more complex. Besides acting as an incubator for artificial intelligence, "Second Life" has already been an important case study in the development of cyber law and the economics and legality of hawking virt
Inside This Article
1. Will artificial intelligence invade Second Life? 2. Advantages of Artificial Intelligence in Virtual Worlds 3. Lots More Information 4. See all Internet articles
Popular culture is filled with different notions of what artificial intelligence should or will be like. There's the all-powerful Skynet from the "Terminator" movies, "Star Wars"-style androids, HAL from "2001: A Space Odyssey," the classic sentient computer program, carrying on a witty conversation through a computer terminal. Soon, we may have to add another to the list. In September 2007, a software company called Novamente, along with the Electric Sheep Company, a producer of add-ons for virtual worlds, announced plans to release artificial intelligences (AI) into virtual worlds like the ultra-popular "Second Life."

Video Game Image Gallery


Image courtesy AFP/Getty Images
Soon players of "Second Life" will have the opportunity to purchase
pets powered by Novamente's "Cognition Engine."
See our video game image gallery.



Novamente's "intelligent virtual agents" would use online games and virtual worlds as a development zone, where they will grow, learn and develop by interacting with humans. The company said that it will start by creating virtual pets that become smarter as they interact with their (human-controlled) avatar owners. (An avatar is the character or virtual representation of a player in a virtual world.) More complex artificially controlled animals and avatars are expected to follow.

Novamente's artificial intelligence is powered by a piece of software called a "Cognition Engine." Pets and avatars powered by the Cognition Engine will feature a mix of automated behaviors and learning and problem-solving capabilities. Ben Goertzel, the CEO of Novamente, said that his company had already created a "fully functioning animal brain" [source: BBC News]. Goertzel envisioned Novamente's first artificial intelligences as dogs and monkeys, initially going on sale at your local virtual pet shop in October 2007.

These virtual pets will work much like real pets -- trainable, occasionally misbehaving, showing the ability learn and perform tasks and responding positively to rewards. After dogs and monkeys, Novamente would then move on to more complex creatures, such as parrots that, like their real-life counterparts, could learn to speak. Finally, the company expects to produce virtual human babies that, propelled by its own artificial intelligence, would grow, develop and learn in the virtual world [source: BBC News].

While we frequently see or read about robots with interesting capabilities, scientists have struggled for decades to create anything approaching a genuine artificial intelligence. A robot may be an expert at one skill, say shooting a basketball, but numerous basic tasks, such as walking down stairs, may be beyond its capabilities. This is where a virtual world has its advantages, Goertzel says.

On the next page, we'll look at why virtual worlds may present the next and best frontier for the development of artificial intelligence.

Video Gallery: AI and Second Life
By researching how children learn language, computer science professor Partha Niyogi seeks to unlock the secret to programming truly "intelligent" machines.
UNICEF has a presence in "Second Life" in the form of an avatar named Mariel. See how UNICEF hopes to take advantage of Second Life to work on behalf of children in this video



NEXual goods for real dollars. The popular virtual world has even been mentioned as a possible virtual training facility for children taking emergency preparedness classes [source: CNET News].

For more information about artificial intelligence in virtual worlds, "Second Life" and other related topics, please check out the links on the next page.

internet

Main > Computer > Internet
Internet
The Internet is so often accessed these days that we may take its functionality for granted. We look to the Internet for news, socializing, shopping, research and more. From HTML code to instant messaging, the HowStuffWorks Internet channel breaks down what's really going on whenever you log on, send an e-mail or post a blog. We also analyze some of the most popular Web sites to see just how they do what they do.

security

Security
Computer security is an increasingly important consideration these days, thanks to networking and the Internet, which mean our computers are more interconnected than ever before. Are you concerned about how to keep your computer's hard drive protected and your personal information safe? The HowStuffWorks articles in this section help you make sense of tactics like firewalls and encryption, and we also show you the latest innovations in computer security.

hardware

Main > Computer > Hardware
Hardware
Hardware, the basic parts that make up your computer, can seem pretty mysterious at first glance. For instance, how is a USB connector able to work with so many different devices? And what are the functions of all those bridges and sockets on a motherboard? The articles and videos in the Hardware section of HowStuffWorks shed light on these essential components of your computer.