READING, England - Computers argued, cracked jokes and parried trick questions, all part of an annual test of artificial intelligence carried out at the University of Reading.

Typing away at split-screen terminals Sunday, a dozen volunteers carried out two conversations at once: one with a chat program, the other with a human. After five minutes, they were asked to say which was which. Some were not sure who - or what - they were talking to.

"There was one time when I was speaking to the two, and there was an element of humor in both conversations. That's the one that stumped me more than others," said Ian Andrews, one of the judges in Reading, just west of London.

Transcripts of the conversations showed some savvy judges ruthlessly trying to trip programs up with questions about the day's weather, the global financial turmoil and the color of their eyes.

"Blue, of course!" answered Eugene Goostman, a "chatbot" designed by Pennsylvania-based programmer Vladimir Vesselov. Eugene was one of five programs competing to pass themselves off as flesh and blood. A sixth program, Alice, dropped out when it could not be set up in time.

Fred Roberts' Elbot scooped the day's top award: the Loebner Artificial Intelligence Prize's bronze medal, for duping three out of 12 judges assigned to evaluate it.

"I wish I was as good at conversation as Elbot," the Hamburg, Germany-based consultant joked after receiving the prize.

The contest draws on the ideas of British mathematician Alan Turing, who came up with a subjective but simple rule for determining whether machines were capable of thought. Writing in 1950, Turing argued that conversation was proof of intelligence. If a computer talked like a human, then for all practical purposes it thought like a human too.

But judging a computer's eloquence was tricky: Humans might be prejudiced against a machine. So Turing devised the test in which a human judge would swap messages simultaneously with a computer and another human, without being told which was which. If the judge had trouble telling his correspondents apart, Turing said, then the computer met the human standard of intelligence.

Each program took a slightly different tack Sunday.

Eugene often made pointed references to his native Odessa and "Aunt Sonya in America."

Cleverbot, designed by Rollo Carpenter, used humor to try to fool the judges.

Roberts said Elbot worked by catching some of the judges off-guard with provocative answers or impishly hinting that it was, in fact, a machine.

"Hi. How's it going?" one judge began.

"I feel terrible today," Elbot replied. "This morning I made a mistake and poured milk over my breakfast instead of oil, and it rusted before I could eat it."

Roberts also said Elbot tried to dominate the conversation to keep it from wandering into areas it was not properly programmed to handle.

Although Turing died in 1954 without laying down precise rules for the competition, American scientist and philanthropist Hugh Loebner has been overseeing an annual series of tests based on Turing's principles since 1991.

The bronze prize handed out by Loebner goes to the piece of software that best mimics human conversation in text form.

No program has won the gold or silver prizes. The silver would go to a machine that could pass a longer version of the Turing Test and fool at least half the judges. The gold would go to a machine that could process audio and visual information rather than just text.

Cybernetics professor Kevin Warwick, one of this year's contest organizers, said passing the test would be something akin to the moment IBM supercomputer Deep Blue beat Russian chess master Garry Kasparov in 1997.

Despite - or maybe because of - his win, Roberts said he did not buy Turing's argument.

"I don't think it's anything like thought," he said of Elbot's conversational prowess. "If you know a magic trick, you know how it's done, it's not magic anymore. Sorry to be so pessimistic."

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By RAPHAEL G. SATTER Associated Press Writer

A Silicon Valley company is claiming a major victory in its efforts to sell computers to schools that might otherwise be enticed by low-cost laptops such as the green-and-white XO from One Laptop Per Child or Intel Corp.'s Classmate PC.

NAIROBI, Kenya - Blackwater Worldwide and other private security firms - some with a reputation for being quick on the trigger in Iraq - are joining the battle against pirates plaguing one of the world's most important shipping lanes off the coast of Somalia.

The growing interest among merchant fleets to hire their own firepower is encouraged by the U.S. Navy and represents a new and potential lucrative market for security firms scaling back operations in Iraq.

But some maritime organizations told The Associated Press that armed guards may increase the danger to ships' crews or that overzealous contractors might accidentally fire on fishermen.

The record in Iraq of security companies like Blackwater, which is being investigated for its role in the fatal shooting of 17 Iraqi civilians in 2007, raises concerns about unregulated activity and possible legal wrangles.

"Security companies haven't always had the lightest of touches in Iraq, and I think Somalia is a pretty delicate situation," said Roger Middleton, who wrote a recent report on piracy in Somalia for Chatham House, a think tank in London.

NATO, with a flotilla of warships due to arrive in Somali waters this weekend, is trying to work out legal and regulatory issues surrounding the use of armed contractors before adopting a position on private security companies.

But the U.S. Navy, part of the coalition already patrolling off the coast of Somalia, says the coalition cannot effectively patrol the 2.5 million square miles of dangerous waters and welcomes the companies.

"This is a great trend," said Lt. Nate Christensen, a spokesman for the Bahrain-based U.S. 5th Fleet. "We would encourage shipping companies to take proactive measures to help ensure their own safety."

Somali officials also approve of the private contractors.

Abdulkadir Muse Yusuf, deputy marine minister of the semiautonomous region of Puntland, said private firms are welcome in Somali waters. As well as fighting piracy, he said, they could help combat illegal fishing and toxic waste dumping.

Some security companies - not all of which let their employees carry lethal weapons - blame trigger-happy operators in Iraq and Afghanistan for tarnishing the reputation of legitimate businesses.

After a series of shootings that killed civilians, Iraqi legislators negotiated an agreement with the U.S. that will remove some of the private contractors' immunity from prosecution. U.S. authorities are investigating Blackwater for improperly bringing weapons into Iraq and for its role in the 2007 Iraqi civilian deaths.

The removal of immunity, Iraq's stabilizing security situation and a glut of security operators in the country have combined to tempt some companies to seek a new market in the pirate-infested Gulf of Aden off Somalia.

Last week, Blackwater announced it was hiring a ship fitted with helicopters and armed guards for escorting vessels past Somalia's pirate-ridden coast Spokeswoman Anne Tyrrell said it had received 15 inquiries so far.

Peter Singer, an expert on private security companies, agrees Africa is a potential growth market, but he says it's unlikely many firms will abandon work in Iraq and Afghanistan, where there are dramatically more business opportunities as long as the wars continue.

"If somehow Iraq ends and you see a shrinking amount of contractors there, most of them are in logistics and training services," Singer added. "None of that carries over to this role."

British firms dominate security work in the Gulf of Aden, but American companies are increasingly getting into the action, according an Associated Press examination of new anti-piracy efforts through interviews in East Africa, Europe and Washington.

In addition to Blackwater, Mississippi-based Hollowpoint, which has not been active in Iraq, says it will provide guards and recover seized ships.

"We'll get your crew and cargo back to you, whether through negotiations or through sending a team in," said CEO John Harris, who is discussing contracts with several companies.

There have been 63 reported attacks on ships off the Somali coast this year alone and probably many more have been carried out. Almost a third of the recorded attacks have been successful.

Ransoms can reach into the millions of dollars. That's a fortune in a failed state like Somalia, where almost half the people depend on aid and warlords plunder food shipments meant for starving children. The money goes to clan-based militias, some of which are fighting in Somalia's civil war.

Cyrus Mody, the manager of the International Maritime Bureau, says private security personnel can offer useful advice to ship captains, but he worries not all companies have clear rules of engagement or have sought legal advice about the consequences of opening fire.

So far hijackings are rarely fatal: One Chinese sailor was executed by pirates when ransom negotiations were going badly, and the two other known deaths resulted from a ricochet and a heart attack.

Mody says armed guards onboard ships may encourage pirates to use their weapons or spark an arms race between predators and prey. Currently, pirates often fire indiscriminately during an attack but don't aim to kill or injure crew. The pirates usually use assault rifles but have rocket-propelled grenades; some reports also say they have mini-cannon.

"If someone onboard a ship pulls a gun, will the other side pull a grenade?" Mody asked.

British contractors stress the importance of intelligence and surveillance, a safe room for the crew to retreat to if the ship is boarded, and the range of non-lethal deterrence measures available.

"The standard approach is for (pirates) to come in with all guns blazing at the bridge because when a boat is stopped it's easier to board," said David Johnson, director of British security firm Eos. "But if you have guns onboard, you are going to escalate the situation. We don't want to turn that part of the world into the Wild West."

Johnson's employees don't carry arms, relying on tactics that can be as simple as greasing or electrifying hand rails, putting barbed wire around the freeboard - the lowest area of the deck - or installing high-pressure fire hoses directed at vulnerable areas of a ship.

One tugboat confused its attackers by going into a high-speed spin when pirates approached, causing the attackers to give up - and leaving the crew sick but safe.

High-tech but non-lethal weapons include dazzle guns, which produce disorienting flashes; microwave guns, which heat up the skin causing discomfort but no long-term damage; and acoustic devices that can blast a wave of painful sound across hundreds of yards.

Johnson believes his company's refusal to carry guns has helped attract business: inquiries have gone up three- to fourfold in the past few months.

Other companies do arm their employees, pointing out that while non-lethal weapons are also carried and greatly preferred, they can be taken out by bullets or a grenade, sustain damage from salt water, and may have a shorter range than some weapons of pirates.

Pirate attacks have driven up insurance premiums tenfold for ships plying the Gulf of Aden, increasing the cost of cargos that include a fifth of the world's oil. But some insurers will slash charges by up to 40 percent if boats hire their own security. Earlier this month, British security firm Hart launched the first joint venture with an insurance company, offering discounted premiums for ships sailing past Somalia that used Hart's guards.

The 20,000 ships that pass through the Gulf of Aden on the way to or from the Suez Canal each year can't avoid the 1,800 miles of Somali coastline without sailing around the entire continent of Africa.

The jump in interest in private contractors - spurred by last month's hijacking of a Ukrainian ship loaded with tanks and other weapons - has brought new players into the market and a flood of business for well-established firms.

Drum Cussac, a specialist maritime security company, says its business has increased 50 percent the last few months. Not operating in Iraq or Afghanistan, the firm has traditionally supplied security teams to luxury yachts like the French Le Ponant, which was hijacked last April with 22 crew members onboard.

Maritime operations manager Michael Angus says the yacht business has doubled. And now, he says, merchant ships such as bulk carriers or oil tankers are asking the company for teams of armed guards, making what was once a seasonal business off Somalia a year-round enterprise.

London-based Olive Group, which protects Shell operations in Iraq, began offering services in the Gulf of Aden earlier this year. Its security consultant, Crispian Cuss, says just the presence of armed guards may be a deterrent. Pirates get information on crews and cargos from contacts in ports or at shipping companies and avoid vessels with armed men on board, he said.

"No client's ship has been approached by pirates while we've been on them," he said.

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Associated Press writers Slobodan Lekic in Brussels, Belgium, David Stringer in London, Richard Lardner in Washington and Salad Duhul in Mogadishu, Somalia, contributed to this report.

By KATHARINE HOURELD Associated Press Writer

DAMASCUS, Syria - U.S. military helicopters launched an extremely rare attack Sunday on Syrian territory close to the border with Iraq, killing eight people in a strike the government in Damascus condemned as "serious aggression."

BAGHDAD - For years, he operated along Syria's remote border where donkeys are the only means of travel. He provided young Arabs from as far away as Morocco and the Persian Gulf with passports, guides and weapons as they slipped into Iraq to wage war.

But recently, the Iraqi man known as Abu Ghadiyah began doing even more - launching his own armed forays into his homeland, U.S. and Iraqi officials say.

Finally the United States lashed out, frustrated it says, after years of vainly pressuring Syria to shut down his network supplying the Sunni insurgency.

The Americans carried out a bold daylight raid Sunday in a dusty farming community of mud and concrete houses known as Abu Kamal, just across the border in Syria. The U.S. says Abu Ghadiyah and several bodyguards were killed. Syria says eight civilians died. At least one villager says U.S. forces seized two men and hauled them away.

Whatever Abu Ghadiyah's fate, the attack targeting him has become a seminal moment - casting rare light on the hidden, complex networks that recruit foreign fighters and then deliver them across Syria to the battlefields of Iraq.

Syria has long insisted it monitors the border and does all it can to stop weapons and fighters.

"They know full well that we stand against al-Qaida," Syrian Foreign Minister Walid al-Moallem said Monday in London. "They know full well we are trying to tighten our border with Iraq."

But the raid and U.S. documents - recently made public - indicate that insurgents operating in the Syrian border region are still providing the materiel that enables suicide attacks, bombings and ambushes to continue inside Iraq.

Even as the insurgency has fallen on rough times - battered and bleeding but not yet defeated - the networks themselves have become more organized, the documents indicate. That raises fears the insurgency could someday arise anew.

The documents also shed light on the murky web of religious extremists, professional smugglers and corrupt Syrian intelligence officials who run the smuggling networks - some of whom view Syria's government in faraway Damascus with contempt.

Until the raid, Abu Ghadiyah, whose real name was Badran Turki al-Mazidih, was mostly unknown outside a tight circle of Western and Iraqi intelligence officers. They tracked his movements, and the al-Qaida commanders who relied on his services, believing him a senior figure in al-Qaida in Iraq.

Abu Ghadiyah housed his recruits both in Damascus and the Syrian port of Latakiya before moving them across the Iraqi border, one senior Iraqi security officer said Tuesday. He spoke on condition of anonymity because he was not authorized to talk to media.

Scores of people are involved in the smuggling networks, officials say. But Iraqi police held special disdain for Abu Ghadiyah, a native of the northern Iraqi city of Mosul believed to be in his early 30s.

Last May, Abu Ghadiyah led a dozen gunmen across the border and attacked an Iraqi police station in Qaim, killing 12 policemen, Iraqi police Lt. Col. Falah al-Dulaimi told The Associated Press on Tuesday. Syrian border guards prevented an Iraqi patrol from pursuing the gunmen back into Syria, the police officer said.

Sunday's raid was launched because of intelligence that Abu Ghadiyah was planning another attack inside Iraq, a senior U.S. official told The Associated Press, also speaking anonymously because the information is classified.

Much of the publicly known information about networks such as Abu Ghadiyah's comes from documents seized during a U.S. military raid last year on a suspected al-Qaida hideout in the Iraqi city of Sinjar.

Those documents include records of about 590 foreign volunteers who entered Iraq from Syria, according to the Combating Terrorism Center at the U.S. Military Academy at West Point. The center released a report last July based largely on the documents.

According to the documents, nearly 100 Syrian coordinators are involved in transporting foreign fighters through Syria. Some are professional smugglers apparently hired by al-Qaida in purely business deals. Others are motivated by al-Qaida's hardline Islamic ideology.

Abu Ghadiyah's real beliefs are unclear, but a U.S. Treasury document says he was appointed as al-Qaida in Iraq's logistics chief for Syria by the group's founder, Abu Musab al-Zarqawi. That suggests Abu Ghadiyah was indeed a true believer.

The coordinators worked with the young Arab volunteers recorded in the Sinjar documents - most of whom came from Saudi Arabia and Libya, with others from as far away as Morocco, Algeria and Yemen.

The volunteers made their way to Syria - some directly from their home countries and others by way of Egypt or Turkey - where they linked up with the coordinators. Some coordinators charged up to $2,500 to help the volunteer fighters reach Iraq.

Once provided with passports and other documents, the volunteers traveled to border areas, where they entered Iraq on foot along with guides from local tribes.

Since 2004, Abu Ghadiyah has organized and supervised much of that traffic, according to U.S. officials.

Interestingly, U.S. officials say they believe that Syria has tried from time to time to crack down on the smugglers and tighten controls along the 350-mile border, bolstering security patrols and erecting sand berms.

But Syria has been unable to keep up the pressure, in part because its government needs support from local tribes and revenue from the bribes the smugglers pay to local officials, according to the Combating Terrorism Center study.

Those sensitivities are apparent in Abu Kamal, where people wear traditional Iraqi clothing and speak with Iraqi accents.

"Most of the inhabitants of the area originally come from areas of Iraq, and there are very strong family ties until this day," said Ahmed al-Khalifa, a lawyer from Abu Kamal. "There is strong sympathy here with whatever happens in Iraq."

Even before the insurgency began, those feelings of kinship encouraged hundreds of volunteers from eastern Syria to pass through Abu Kamal to Iraq to defend the country against U.S. forces in the 2003 invasion.

After Saddam Hussein's regime collapsed, Syria set up new checkpoints around the town to prevent more volunteers from getting to Iraq, the terrorism center report said.

But Syrian public outrage over U.S. attacks against Iraqi Sunnis in Fallujah in 2004 prompted the Syrians to relax the restrictions and allow more fighters - this time many of them Saudis - to enter Iraq, the report said.

A third wave of volunteers began in 2006 as fighting between Iraqi Sunnis and Shiites intensified, the report said. The current wave is continuing, although at a lower level because many Iraqi Sunnis have abandoned the insurgency.

There may be plenty of others to take Abu Ghadiyah's place, the U.S. says - including a brother Akram, and a cousin Ghazi Fezza al-Mazidih, whom the US. described in a February report as his "right hand man."

Overall, the number of foreign fighters attracted to Iraq may be down, the West Point study cautioned, "But the logistical network to move them has become more organized."

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Associated Press writers Zeina Karam in Abu Kamal, Syria, Qassim Abdul-Zahra in Baghdad and Pamela Hess in Washington contributed to this report.

By ROBERT H. REID Associated Press Writer