prompt_front: Now, answer the following question based on the text below, only give me the answer and do not output any other words.

Question: What does the new Iraqi Body Count organization do?

Read the following text and answer briefly.

Context 1: Ann's Mega Dub: 12/19/10 - 12/26/10
Got o have a penis to be an expert
Thursday on NPR's Fresh Air, Terry Gross wanted to talk film and music  Since women don't know a thing about either and aren't interested in either, Terry had to find men who were 'experts 'This is C I 's " Iraq snapshot Friday, December 24, 2010  Chaos and violence continue, Nouri's incomplete Cabinet continues to receive criticism, a father offers an 'excuse' for killing his own daughter, and more Marci Stone (US Headlines Examiner) reports, "Friday afternoon, Santa is currently in Baghdad, Iraq and on his next stop is Moscow, Russia, according to the 2010 NORAD Santa Tracker  The North American Aerospace Defense Command (NORAD) has been tracking Santa as he makes his annual journey throughout the world " Gerald Skoning (Palm Beach Post) quotes Santa saying, "We send our special wishes for peace and goodwill to all  That includes the people of Iraq, Afghanistan, Iran and North Korea " Please note that this is Santa's seventh trip to Iraq since the start of the Iraq War and, as usual, his journey was known in advance  No waiting until he hit the ground to announce he was going to Iraq -- the way George The Bully Boy Bush had to and the way US President Barack Obama still has to  In the lead up to Santa's yearly visit, many 'authorities' in Iraq began insisting that Christmas couldn't be celebrated publicly, that even Santa was banned  Gabriel Gatehouse (BBC News) quotes Shemmi Hanna stating, "I wasn't hurt but I wish that I had been killed  I wish I had become a martyr for this church, but God kept me alive for my daughters " Shemmi Hanna was in Our Lady of Salvation Church in Baghdad when it was assaulted October 31st and she lost her husband, her son, her daughter-in-law and her infant grandson in the attack  The October 31st attack marks the latest wave of violence targeting Iraqi Christians  The violence has led many to flee to northern Iraq (KRG) or to other countries  Zvi Bar'el (Haaretz) notes, "This week the Iraqi legislature discussed the Christians' situation and passed a resolution in principle to help families who fled  However, the parliament does not know where the Christians are, how many are still in Iraq, in their homes, and how many have found asylum in Iraqi Kurdistan " John Leland (New York Times) reports:The congregants on Friday night were fewer than 100, in a sanctuary built for four or five times as many  But they were determined  This year, even more than in the past, Iraqi's dwindling Christian minority had reasons to stay home for Christmas  "Yes, we are threatened, but we will not stop praying," the Rev  Meyassr al-Qaspotros told the Christmas Eve crowd at the Sacred Church of Jesus, a Chaldean Catholic church  "We do not want to leave the country because we will leave an empty space " Raheem Salman (Los Angeles Times) reports, "Rimon Metti's family will go to Christian services on Christmas Day, but his relatives will be praying for their own survival and wondering whether this is their last holiday season in Baghdad  If they had any grounds for optimism about the future of their faith in Iraq, it vanished this year amid repeated attacks on fellow believers " Shahsank Bengali (McClatchy Newspapers) adds, "Nearly two months after a shocking assault by Islamist militants, Our Lady of Salvation Catholic Church will commemorate Christmas quietly, with daytime mass and prayers for the dead, under security fit more for a prison than a house of worship  It is the same at Christian churches across Baghdad and northern Iraq, where what's left of one of the world's oldest Christian communities prepares to mark perhaps the most somber Christmas since the start of the Iraq war "Meanwhile Taylor Luck (Jordan Times) reports on Iraqi refugees in Jordan:Although the calendar will say December 25, for Theresa, Saturday will not be Christmas  There will be no cinnamon klecha cooling on the dining room table, no outdoor ceramic nativity scene, no readings of hymns with relatives  The 63-year-old Iraqi woman has even refused to put up Christmas lights in the crowded two-room Amman hotel apartment she has called home since fleeing Baghdad last month "There is no holiday spirit  All we have is fear," she said This holiday will instead mark another year without news from her 46-year-old son, who was kidnapped outside Baghdad in late 2006 From Turkey, Sebnem Arsu (New York Times -- link has text and video) notes the increase in Iraq refugees to the country since October 31st and quotes Father Emlek stating, "I've never seen as many people coming here as I have in the last few weeks  They also go to Lebanon, Jordan and Syria but it seems that Turkey is the most popular despite the fact that they do not speak the language " Jeff Karoub (AP) reports on the small number of Iraqi refugees who have made it to the US and how some of them "struggle with insomnia, depression and anxiety "One group in Iraq who can openly celebrate Christmas are US service members who elect to  Barbara Surk (AP) reports that tomorrow Chief Warrant Officer Archie Morgan will celebrate his fourth Christmas in Iraq and Captain Diana Crane is celebrating her second Christmas in Iraq: "Crane was among several dozen troops attending a Christmas Eve mass in a chapel in Camp Victory, an American military base just outside Baghdad " Marc Hansen (Des Moines Reigster) speaks with six service members from Iowa who are stationed in Iraq  Sgt 1st Class Dennis Crosser tells Hansen, "I certainly understand from reading the paper what's going on in Afghanistan and the attention definitely needs to be on the troops there  But everyone serving here in Operation New Dawn appreciates a little bit of attention as we finish this up "Today Jiang Yu, China's Foreign Minister, issued the following statement, "We welcome and congratulate Iraq on forming a new government  We hope that the Iraqi Government unite all its people, stabilize the security situation, accelerate economic reconstruction and make new progress in building its country " James Cogan (WSWS) reports:US State Department official Philip Crowley declared on Wednesday that Washington had not "dictated the terms of the government"  In reality, constant American pressure was applied to Maliki, Allawi, Kurdish leaders and other prominent Iraqi politicians throughout the entire nine-month process to form a cabinet  The US intervention included numerous personal phone calls and visits to Baghdad by both President Barack Obama and Vice President Joe Biden The key objective of the Obama administration has been to ensure that the next Iraqi government will "request" a long-term military partnership with the US when the current Status of Forces Agreement (SOFA) expires at the end of 2011  The SOFA is the legal basis upon which some 50,000 American troops remain in Iraq, operating from large strategic air bases such as Balad and Tallil and Al Asad  US imperialism spent billions of dollars establishing these advanced bases as part of its wider strategic plans and has no intention of abandoning them Cogan's only the second person to include the SOFA in his report  Some are impressed with the 'feat' of taking nearly ten months to form a government, stringing the country along for ten months while no decisions could go through  The editorial board of the Washington Post, for example, was full of praise yesterday  Today they're joined by Iran's Ambassador to Iraq, Hassan Danaiifar  The Tehran Times reports that Danaiifar was full of praise today hailing the "positive and final step which ended the 10-month political limbo in Iraq " However, Danaiifar was less pie-in-the-sky than the Post editorial board because he can foresee future problems as evidenced by his statement, "We may witness the emergence of some problems after one and half of a year -- for example, some ministers may be impeached " Of course, there are already many clouds on the horizon, even if Iranian diplomats and Post editorial boards can't suss them out  For example, Ben Bendig (Epoch Times) noted the objection of Iraq's female politicians to Nouri al-Maliki's decision to nominate only one woman (so far) to his Cabinet: "Some 50 female lawmakers went to the country's top leadership, the United Nations and the Arab League to voice their concern and desire for increased representation " BNO notes that protest and also that a group of Iraqi MPs are alleging that Iraqiya bought seats in the Cabinet via money exchanged in Jordan  UPI adds, "Maliki, a Shiite who has a long history of working with Tehran, has named himself acting minister of defense, interior and national security, three most powerful and sensitive posts in the government he is stitching together  Although Maliki appears to be bending over backward to accommodate rivals among Iraq's Shiite majority as well as minority Sunnis and Kurds in his administration in a spirit of reconciliation, he is unlikely to relinquish those ministries that dominate the security sector " DPA reports, "Sheikh Abdel-Mahdi al-Karbalaei, a confident of influential Shiite spiritual leader Ayatollah Ali al-Sistani, said that the new cabinet is 'below the standards' Iraqi citizens had hoped for and suggested it could prove to be weaker than the previous government " Ranj Alaaldin (Guardian) also spots clouds on the horizon:Lasting peace and stability depends on resolving outstanding disputes with the Kurds on oil, revenue-sharing, security and the disputed territories (Kirkuk in particular)  The Kurds, rather than exploiting their kingmaker position to take a stronger proportion of ministries in Baghdad (they are taking just one major portfolio – the foreign ministry), are instead banking on guarantees from Maliki to implement their list of 19 demands that includes resolving the above disputes in their favour They may have been naive, though  With their historical and federalist partners, the Islamic supreme council of Iraq in decline, the Kurds may be isolated in the new government – a government dominated by the nationalistic and centrist characteristics of the INM, the Sadrists and indeed State of Law Maliki may, therefore, turn out to be unable to grant concessions even if he wanted to and could use Osama Nujayfi, the new ultra-nationalist speaker of parliament and Kurdish foe, to absorb the Kurdish criticism and insulate himself from any attacks AP reports that Iraqi police sought out a 19-year-old woman because of rumors that she was working with al Qaida in Mesopotamia only to be greeted with the news that her father allegedly killed her and the father showed the police where he buried the woman       last month  The story begs for more than it offers  The most obvious observation is: what does it say that a woman's allegedly killed by her father and no one says a word for over a month? After that, it should probably be noted that there are many men in Iraq killing women who, no doubt, would love to also be able to pin the blame on al Qaida  In other violence, Reuters notes a house bombing in Haswa which claimed the life of Mohammed al-Karrafi, "his wife, two sons and a nephew" -- as well as injuring four more people, and a Samarra roadside bombing which claimed the lives of 2 police officers  DPA notes it was two homes bombed in Haswa and that the Samarra roadside bombing also injured four Iraqi soldiers  Jomana Karadsheh (CNN) reports, "Another policeman was wounded in Baghdad Friday night when a roadside bomb detonated by a police patrol, an Interior Ministry official told CNN "And we'll close with this from Peace Mom Cindy Sheehan's latest Al Jazeera column:The recent repeal of the US military policy of "Don't ask, don't tell" is far from being the human rights advancement some are touting it to be  I find it intellectually dishonest, in fact, illogical on any level to associate human rights with any military, let alone one that is currently dehumanising two populations as well as numerous other victims of it's clandestine "security" policies Placing this major contention aside, the enactment of the bill might be an institutional step forward in the fight for "equality"; however institutions rarely reflect reality Do we really think that the US congress vote to repeal the act and Obama signing the bill is going to stop the current systemic harassment of gays in the military?While I am a staunch advocate for equality of marriage and same-sex partnership, I cannot - as a peace activist - rejoice in the fact that now homosexuals can openly serve next to heterosexuals in one of the least socially responsible organisations that currently exists on earth: The US military It is an organisation tainted with a history of intolerance towards anyone who isn't a Caucasian male from the Mid-West  Even then I'm sure plenty fitting that description have faced the terror and torment enshrined into an institution that transforms the pride and enthusiasm of youth into a narrow zeal for dominating power relations And we'll close with this from Francis A  Boyle's "2011: Prospects for Humanity?" (Global Research):Historically, this latest eruption of American militarism at the start of the 21st Century is akin to that of America opening the 20th Century by means of the U S -instigated Spanish-American War in 1898  Then the Republican administration of President William McKinley stole their colonial empire from Spain in Cuba, Puerto Rico, Guam, and the Philippines; inflicted a near genocidal war against the Filipino people; while at the same time illegally annexing the Kingdom of Hawaii and subjecting the Native Hawaiian people (who call themselves the Kanaka Maoli) to near genocidal conditions  Additionally, McKinley's military and colonial expansion into the Pacific was also designed to secure America's economic exploitation of China pursuant to the euphemistic rubric of the "open door" policy  But over the next four decades America's aggressive presence, policies, and practices in the "Pacific" would ineluctably pave the way for Japan's attack at Pearl Harbor on Dec  7, 194l, and thus America's precipitation into the ongoing Second World War  Today a century later the serial imperial aggressions launched and menaced by the Republican Bush Jr  administration and now the Democratic Obama administration are threatening to set off World War III  By shamelessly exploiting the terrible tragedy of 11 September 2001, the Bush Jr  administration set forth to steal a hydrocarbon empire from the Muslim states and peoples living in Central Asia and the Persian Gulf under the bogus pretexts of (1) fighting a war against international terrorism; and/or (2) eliminating weapons of mass destruction; and/or (3) the promotion of democracy; and/or (4) self-styled "humanitarian intervention " Only this time the geopolitical stakes are infinitely greater than they were a century ago: control and domination of two-thirds of the world's hydrocarbon resources and thus the very fundament and energizer of the global economic system – oil and gas  The Bush Jr / Obama administrations have already targeted the remaining hydrocarbon reserves of Africa, Latin America, and Southeast Asia for further conquest or domination, together with the strategic choke-points at sea and on land required for their transportation  In this regard, the Bush Jr  administration announced the establishment of the U S  Pentagon's Africa Command (AFRICOM) in order to better control, dominate, and exploit both the natural resources and the variegated peoples of the continent of Africa, the very cradle of our human species  This current bout of U S  imperialism is what Hans Morgenthau denominated "unlimited imperialism" in his seminal work Politics Among Nations (4th ed  1968, at 52-53): The outstanding historic examples of unlimited imperialism are the expansionist policies of Alexander the Great, Rome, the Arabs in the seventh and eighth centuries, Napoleon I, and Hitler  They all have in common an urge toward expansion which knows no rational limits, feeds on its own successes and, if not stopped by a superior force, will go on to the confines of the political world  This urge will not be satisfied so long as there remains anywhere a possible object of domination--a politically organized group of men which by its very independence challenges the conqueror's lust for power  It is, as we shall see, exactly the lack of moderation, the aspiration to conquer all that lends itself to conquest, characteristic of unlimited imperialism, which in the past has been the undoing of the imperialistic policies of this kind…  On 10 November 1979 I visited with Hans Morgenthau at his home in Manhattan  It proved to be our last conversation before he died on 19 July 1980  Given his weakened physical but not mental condition and his serious heart problem, at the end of our necessarily abbreviated one-hour meeting I purposefully asked him what he thought about the future of international relations  iraqbbc newsgabriel gatehousethe new york timesjohn lelandhaaretzzvi bar'elthe jordan timestaylor luckthe associated pressjeff karoubthe los angeles timesraheem salmancnnjomana karadsheh
Terry thinks she's a man
Yesterday on NPR's Fresh Air the hour went to a male TV critic  It's always a man with Terry  Always  And somebody tell her that a snotty, snooty TV critic really doesn't make for good programming This is C I 's "Iraq snapshot:" Thursday, December 23, 2010  Chaos and violence continue, Iraqi women make clear their displeasure over the Cabinet make up, Daniel Ellsberg and Veterans for Peace get some recognition, and more  Last Thursday a protest held outside the White House  One of the organizers was Veterans for Peace and Pentagon Papers whistle blower Daniel Ellsberg participated and spoke  Juana Bordas (Washington Post) advocates for both of them to be named persons of the year: Veterans for Peace and Daniel Ellsberg should be this year's person of the year because of their courage and bravery to stand up for all of us who believe that "war is not the answer " Moreover in a time of economic recession, the war machine is bankrupting our country  As John Amidon, a Marine Corps veteran from Albany asked at the White House protest, "How is the war economy working for you?"While unemployment rates hover near 10 percent, there is no doubt that the U S  economy and quality of life is faltering  Worldwide we are 14th in education, 37th in the World Health Organization's ranking on medical systems, and 23rd in the U N  Environmental Sustainability Index on being most livable and greenest benefits  There is one place we take the undeniable world lead  The US military spending accounts for a whopping 46 5 percent of world military spending--the next ten countries combined come in at only 20 7 percent  Linda Pershing (Truthout) reports, "Responding to a call from the leaders of Stop These Wars(1) - a new coalition of Veterans for Peace and other activists - participants came together in a large-scale performance of civil resistance  A group of veterans under the leadership of Veterans for Peace members Tarak Kauff, Will Covert and Elaine Brower, mother of a Marine who has served three tours of duty in Iraq, sponsored the event with the explicit purpose of putting their bodies on the line  Many participants were Vietnam War veterans; others ranged from Iraq and Afghanistan war veterans in their 20s and 30s to World War II vets in their 80s and older  They were predominately white; men outnumbered women by at least three to one  After a short rally in Lafayette Park, they formed a single-file procession, walking across Pennsylvania Avenue to the solemn beat of a drum  As they reached the police barricade (erected to prevent them from chaining themselves to the gate, a plan they announced on their web site), the activists stood shoulder to shoulder, their bodies forming a human link across the 'picture postcard' tableau in front of the White House " Maria Chutchian (Arlington Advocate) quotes, participant Nate Goldshlag (Vietnam veteran) stating, ""There was a silent, single file march around Lafayette Park to a drum beat  Then we went in front of the White House,  There were barricades set up in front of white house fence  So when we got there, we jumped over barricades and were able to get right next to the White House fence " Participant Linda LeTendre (Daily Gazette) reports: At the end of the rally, before the silent, solemn procession to the White House fence, in honor of those killed in Iraq and Afghan wars of lies and deceptions, the VFP played taps and folded an American flag that had been left behind at a recent funeral for the veteran of one of those wars  Two attendees in full dress uniform held and folded the flag  I had the image of all of the people who stood along the roads and bridges when the bodies of the two local men, Benjamin Osborn and David Miller, were returned to the Capital District  I thought if all of those people were here now or spoke out against war these two fine young men might still be with us I was blessed enough to be held in custody with one of those in uniform; a wonderful young man who had to move from his hometown in Georgia because no one understood why as a veteran he was against these wars  Even his family did not understand  (He remains in my prayers )Our plan was to attach ourselves to the White House fence until President Obama came out and talked to us or until we were arrested and dragged away  I don't have to tell you how it ended Mr  Ellsberg was one of 139 people arrested at that action  We've noted the protest in pretty much every snapshot since last Thursday  If something else comes out that's worth noting on the protest, we'll include it  We will not include people who don't have their facts and it's really sad when they link to, for example, Guardian articles and the links don't even back them up  It's real sad, for example, when they're trashing Hillary (big strong men that they are) and ripping her apart and yet Barack? "Obama's inaccurate statements"??? What the hell is that? You're inferring he lied, say so  Don't be such a little chicken s**t  It's especially embarrasing when you're grandstanding on 'truth ' Especially when you're the little s**t that clogged up the public e-mail account here in the summer of 2008 whining that you were holding Barack to a standard, then admitting that you weren't, then whining that if you did people would be mean to you  Oh, that's sooooooo sad  Someone might say something bad about you  The horror  You must suffer more than all the people in Iraq and Afghanistan combined  While the action took place in DC, actions also took place in other cities  We've already noted NYC's action this week, Doug Kaufmann (Party for Socialism & Liberation) reports on the Los Angeles action: Despite heavy rain, over 100 people gathered in Los Angeles on the corner of Hollywood and Highland to demand an end to the U S  wars on Afghanistan and Iraq  People came from as far as Riverside to protest, braving what Southern California media outlets have dubbed the "storm of the decade " The demonstration, initiated and led by the ANSWER Coalition, broke the routine of holiday shopping and garnered support from activists and even passers by, who joined in chanting "Money for jobs and education -- not for war and occupation!" and "Occupation is a crime -- Iraq, Afghanistan, Palestine!" Protesters held banners reading, "U S /NATO Out of Afghanistan!" and "Yes to jobs, housing and education -- no to war, racism and occupation!"Speakers at the demonstration included representatives of Korean Americans for Peace, ANSWER Coalition, KmB Pro-People Youth, Veterans for Peace, Party for Socialism and Liberation and National Lawyers Guild  Tuesday, Nouri al-Maliki managed to put away the political stalemate thanks to a lot of Scotch -- tape to hold the deal together and booze to keep your eyes so crossed you don't question how someone can claim to have formed a Cabinet when they've left over ten positions to be filled at a later date  One group speaking out is women  Bushra Juhi and Qassmi Abdul-Zahra (AP) report, "Iraq's female lawmakers are furious that only one member of the country's new Cabinet is a woman and are demanding better representation in a government that otherwise has been praised by the international community for bringing together the country's religious sects and political parties " As noted Tuesday, though represenation in Parliament is addressed in Iraq's Constitution, there is nothing to address women serving in the Cabinet  Aseel Kami (Reuters) notes one of the most damning aspects of Nouri's chosen men -- a man is heaing the Ministry of Women's Affairs  Iraqiya's spokesperson Maysoon Damluji states, "There are really good women who could do wel       they cannot be neglected and marginalized " Al-Amal's Hanaa Edwar states, "They call it a national (power) sharing government  So where is the sharing? Do they want to take us back to the era of the harem? Do they want to take us back to the dark ages, when women were used only for pleasure " Deborah Amos (NPR's All Things Considered) reports that a struggle is going on between secular impulses and fundamentalist ones  Gallery owner Qasim Sabti states, "We know it's fighting between the religious foolish man and the civilization man  We know we are fighting like Gandhi, and this is a new language in Iraqi life  We have no guns  We do not believe in this kind of fighting " Deborah Amos is the author of Eclipse of the Sunnis: Power, Exile, and Upheaval in the Middle East  Meanwhile Nizar Latif (The National) reports that distrust is a common reaction to the new government in Baghdad and quotes high school teacher Hussein Abed Mohammad stating, "Promises were made that trustworthy, competent people would be ministers this time around, but it looks as if everything has just been divided out according to sectarian itnerests  No attention has been paid to forming a functioning government, it is just a political settlement of vested interests  I'm sure al Maliki will have the same problems in his next four years as he had in the last four years " Days away from the ten months mark, Nouri managed to finally end the stalemate  Some try to make sense of it and that must have been some office party that the editorial board of the Washington Post is still coming down from judging by "A good year in Iraq " First up, meet the new Iraqi Body Count -- an organization that provides cover for the war and allows supporters of the illegal war to point to it and insist/slur "Things aren't so bad!" Sure enough, the editorial board of the Post does just that noting the laughable "civilian deaths" count at iCasualities  As we noted -- long, long before we walked away from that crap ass website, they're not doing a civilian count 
Context 2: A system and method for generating a stream of content for a channel  The channel application includes a content categorizer, a scoring engine and a channel engine  The content categorizer categorizes new content items received from heterogeneous data sources  The channel engine identifies a channel category for a user based at least in part on at least one of a historical trend and a user activity  The scoring engine queries the new content items based on the channel category and at least one other channel attribute  The scoring engine retrieves candidate content items that include the channel category and the other channel attribute  The scoring engine then generates a stream of content from the candidate content items for the channel 
This application claims priority under 35 USC §120 to U S  application Ser  No  13/225,209, entitled, “Generating a Stream of Content for a Channel,” filed on Sep  2, 2011, and claims priority under 35 USC §119(e) to U S  Application No  61/424,636, entitled “Scoring Stream Items with Models Based on User Interests” filed Dec  18, 2010, the entireties of which are herein incorporated by reference 
The specification relates to a system and method for generating a stream of content for a channel  In particular, the specification relates to generating a stream of content for a channel based on user interests and historical trends 
Many consumers of digital media have two somewhat contradictory goals: keep apprised of information in the areas they already find interesting and discover new content that is also enjoyable  Keeping apprised of information can become burdensome in the digital age because there is so much information  Hence, there is a need to present the best and most relevant information, without overwhelming the consumer  Furthermore, consumers have varied interests depending on the time of a year or a day  As a result, there is also a need to cater to the time dependent changes in the consumer's interests while presenting information  Similarly, discovering new content is difficult when the consumer is overburdened with existing content 
Prior attempts to solve these problems allow consumers to create personalized sections in feed aggregation websites that are defined by keywords  Often, these personalized sections present any item that includes the keywords even though the item is not of interest to the consumer, per se  In another method, consumers are allowed to manually subscribe to Really Simple Syndication (RSS) feeds from multiple websites  This method often leads to the consumer viewing multiple items which contain redundant information 
In some examples, the specification describes a system and method for generating a stream of content for a channel using a channel application  The channel application includes a processing unit, a model generation engine, a scoring engine, a collaborative filtering engine, a content categorizer, a channel engine, and a user interface engine  The model generation engine generates a model that is used to determine suggestions for channels  The content categorizer categorizes new content items received from heterogeneous data sources  The channel engine identifies a channel category for a user based on at least one of a historical trend and a user activity  The historical trend is at least one of an increase in a number of new content items for a content category, an increase in a number of times one of the new content items is accessed and an event  A scoring engine queries the new content items based on the channel category and at least one other channel attribute  The scoring engine receives candidate content items that include the channel category and the at least one other channel attribute  The scoring engine then generates a stream of content from the candidate content items for the channel  The scoring engine transmits the stream of content to the channel engine, which generates a channel 
In one embodiment, the user interface engine generates a user interface for the user to define the channel category and the channel attribute  The scoring engine queries the new content items based on the user defined channel category and channel attribute and then generates the stream of content  In another embodiment, the channel engine enables the user to subscribe to an existing channel 
In one embodiment, the channel engine enables the user to share the channel with at least one of a friend of the user, a community, a group, and an internet user 
The specification is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals are used to refer to similar elements 
FIG  1A is a high-level block diagram illustrating one embodiment of a system for generating a stream of content for a channel 
FIG  1B is a block diagram illustrating one embodiment of a channel application 
FIG  2 is a high-level block diagram illustrating another embodiment of a system for generating a stream of content for a channel 
FIG  3A is a block diagram of one embodiment of the channel engine in more detail 
FIG  3B is a block diagram of one embodiment of the scoring engine in more detail 
FIG  4 is a graphic representation of a user interface that displays the stream of content of a channel 
FIG  5 is a graphic representation of a user interface that allows a user to define or customize a channel 
FIG  6 is a flow diagram of one embodiment of a method for generating a stream of content for a channel 
FIG  7 is a flow diagram of another embodiment of a method for generating a stream of content for a channel 
A system and method for generating a stream of content for a channel is described below  In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the specification  It will be apparent, however, to one skilled in the art that the embodiments can be practiced without these specific details  In other instances, structures and devices are shown in block diagram form in order to avoid obscuring the specification  For example, the specification is described in one embodiment below with reference to user interfaces and particular hardware  However, the description applies to any type of computing device that can receive data and commands, and any peripheral devices providing services 
Some portions of the detailed descriptions that follow are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory  These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art  An algorithm is here, and generally, conceived to be a self consistent sequence of steps leading to a desired result  The steps are those requiring physical manipulations of physical quantities  Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated  It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like 
It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities  Unless specifically stated otherwise as apparent from the following discussion, it is appreciated that throughout the description, discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” “displaying,” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices 
The specification also relates to an apparatus for performing the operations herein  This apparatus may be specially constructed for the required purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer  Such a computer program may be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, flash memories including USB keys with non-volatile memory, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus 
An embodiment can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment containing both hardware and software elements  A preferred embodiment is implemented in software, which includes but is not limited to firmware, resident software, microcode, etc 
Furthermore, an embodiment can take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system  For the purposes of this description, a computer-usable or computer readable medium can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device 
FIG  1A illustrates a block diagram of a system 100 for generating a stream of content for a channel according to one embodiment  The system 100 includes user devices 115 a, 115 n that are accessed by users 125 a, 125 n, a social network server 101, a third party server 107, a ratings server 139, an email server 141, an entertainment server 137, and a search server 135  The ratings server 139 includes websites for rating places, people or objects (e g  Google Hotpot)  The entertainment server 137 includes websites with entertaining information, such as news articles  In FIG  1A and the remaining figures, a letter after a reference number, such as “115 a” is a reference to the element having that particular reference number  A reference number in the text without a following letter, such as “115,” is a general reference to any or all instances of the element bearing that reference number  In the illustrated embodiment, these entities are communicatively coupled via a network 105 
In one embodiment, the channel application 103 a is operable on the social network server 101, which is coupled to the network via signal line 104  The social network server 101 also contains a social network application 109 and a social graph 179  Although only one social network server 101 is shown, persons of ordinary skill in the art will recognize that multiple social network servers 101 may be present  A social network is any type of social structure where the users are connected by a common feature, for example, Google+  The common feature includes friendship, family, work, an interest, etc  The common features are provided by one or more social networking systems, such as those included in the system 100, including explicitly-defined relationships and relationships implied by social connections with other online users, where the relationships form a social graph 179  In some examples, the social graph 179 reflects a mapping of these users and how they are related 
In another embodiment, the channel application 103 b is stored on a third-party server 107, which is connected to the network via signal line 106  The third-party server 107 includes software for generating a website (not shown)  In one embodiment, the notifying application generates a user interface that is incorporated into the website  Although only one third-party server 107 is shown, persons of ordinary skill in the art will recognize that multiple third-party servers 107 may be present 
In yet another embodiment, the channel application 103 c is stored on a user device 115 a, which is connected to the network via signal line 108  The user device 115 a is any computing device that includes a memory and a processor, such as a personal computer, a laptop, a smartphone, a cellular phone, a personal digital assistant (PDA), etc  The user 125 a interacts with the user device 115 a via signal line 110  Although only two user devices 115 a, 115 n are illustrated, persons of ordinary skill in the art will recognize that any number of user devices 115 n are available to any number of users 125 n 
The network 105 is a conventional type, wired or wireless, and may have any number of configurations such as a star configuration, token ring configuration or other configurations known to those skilled in the art  Furthermore, the network 105 may comprise a local area network (LAN), a wide area network (WAN) (e g , the Internet), and/or any other interconnected data path across which multiple devices may communicate  In yet another embodiment, the network 105 may be a peer-to-peer network  The network 105 may also be coupled to or includes portions of a telecommunications network for sending data in a variety of different communication protocols  In yet another embodiment, the network 105 includes Bluetooth communication networks or a cellular communications network for sending and receiving data such as via short messaging service (SMS), multimedia messaging service (MMS), hypertext transfer protocol (HTTP), direct data connection, WAP, email, etc  While only one network 105 is coupled to the user devices 115 a, 115 n, the social network server 101, and the third party server 107, in practice any number of networks 105 can be connected to the entities 
The channel application 103 receives data for generating a stream of content for a channel from heterogeneous data sources  In one embodiment, the channel application 103 receives data from a third-party server 107, a social network server 101, user devices 115 a, 115 n, a search server 135 that is coupled to the network 105 via signal line 136, an entertainment server 137 that is coupled to the network 105 via signal line 138, a ratings server 139 that is coupled to the network 105 via signal line 140 and an email server 141 that is coupled to the network 105 via signal line 142  In one embodiment, the search server 135 includes a search engine 143 for retrieving results that match search terms from the Internet  In one embodiment, the search engine 143 is powered by Google®  In one embodiment, the channel application 103 generates a model based on the data from the heterogeneous data sources, identifies a channel category based on a user's activities and historical trends, receives candidate content items that include the channel category from heterogeneous data sources, scores the candidate content items by comparing them to the model, and generates a stream of content for the channel 
Referring now to FIG  1B, the channel application 103 is shown in detail  FIG  1B is a block diagram of a computing device 200 that includes the channel application 103, a memory 237 and a processor 235  In one embodiment, the computing 200 device is a social network server 101  In another embodiment, the computing device 200 is a third party server 107  In yet another embodiment, the computing device 200 is a user device 115 a 
The processor 235 comprises an arithmetic logic unit, a microprocessor, a general purpose controller, or some other processor array to perform computations and provide electronic display signals to a display device  The processor 235 is coupled to the bus 220 for communication with the other components via signal line 236  Processor 235 processes data signals and may comprise various computing architectures including a complex instruction set computer (CISC) architecture, a reduced instruction set computer (RISC) architecture, or an architecture implementing a combination of instruction sets  Although only a single processor is shown in FIG  1B, multiple processors may be included  The processing capability may be limited to supporting the display of images and the capture and transmission of images  The processing capability might be enough to perform more complex tasks, including various types of feature extraction and sampling  It will be obvious to one skilled in the art that other processors, operating systems, sensors, displays, and physical configurations are possible 
The memory 237 stores instructions and/or data that may be executed by processor 235  The memory 237 is coupled to the bus 220 for communication with the other components via signal line 238  The instructions and/or data may comprise code for performing any and/or all of the techniques described herein  The memory 237 may be a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, flash memory, or some other memory device known in the art  In one embodiment, the memory 237 also includes a non-volatile memory or similar permanent storage device and media such as a hard disk drive, a floppy disk drive, a CD-ROM device, a DVD-ROM device, a DVD-RAM device, a DVD-RW device, a flash memory device, or some other mass storage device known in the art for storing information on a more permanent basis 
In one embodiment, the channel application 103 comprises a processing unit 202, a model generation engine 207, a scoring engine 211, a collaborative filtering engine 217, a content categorizer 250, a channel engine 240, and a user interface engine 260 that are coupled to a bus 220 
The processing unit 202 is software including routines for receiving information about a user's interests, activities and social connections and for storing the information in the memory 237  In one embodiment, the processing unit 202 is a set of instructions executable by the processor 235 to provide the functionality described below for processing the information  In another embodiment, the processing unit 202 is stored in the memory 237 of the computing device 200 and is accessible and executable by the processor 235  In either embodiment, the processing unit 202 is adapted for cooperation and communication with the processor 235, the model generation engine 207, and other components of the computing device 200 via signal line 222 
The processing unit 202 obtains information about users from user input and/or prior actions of a user across a range of heterogeneous data sources including search (such as web, video, news, maps, alerts), entertainment (such as news, video, a personalized homepage, blogs, a reader, gadget subscriptions), social activity (such as interactions through email, profile information, text messaging such as short message service (SMS), microblogs, geographical locations, comments on photos, a social graph and other social networking information), and activity on third-party sites (such as websites that provide ratings, reviews and social networks where users indicate that they approve of content)  This information is obtained, for example, from a user's search history, browsing history and other interactions with the Internet  The processing unit 202 stores the information with a designation of the source of the information 
In one embodiment, there are multiple processing units 202 that each receive data from a different heterogeneous data source  In another embodiment, the user information is received by the same processing unit 202  The processing unit 202 transmits the user information to memory 237 for storage  In one embodiment, the memory 237 partitions the user information from each heterogeneous data source in a separate data storage location  In another embodiment, the user information from heterogeneous data sources is stored in the same location in the memory 237  In yet another embodiment, the memory 237 partitions the model and the stream of content into separate storage locations as well 
The model generation engine 207 is software including routines for retrieving the user information from the memory 237 and generating a model based on the user information  In one embodiment, the model generation engine 207 is a set of instructions executable by the processor 235 to provide the functionality described below for generating the model  In another embodiment, the model generation engine 207 is stored in the memory 237 of the computing device 200 and is accessible and executable by the processor 235  In either embodiment, the model generation engine 207 is adapted for cooperation and communication with the processor 235, the processing unit 202, the scoring engine 211, the channel engine 240 and other components of the computing device 200 via signal line 224 
The model generation engine 207 receives user information from a variety of sources including, for example, queries, clicks, news clicks, gadgets, email interactions, etc , extracts features from the information and generates a model based on the extracted features  The model determines the relevance of items to users, along with floating point values to indicate the extent to which the relevance holds  Examples include liking a source, a primary location and a list of interests  The interests are generated from explicit information and inferred information  Explicit information is derived, for example, from a user's list of interests on a social network or indicating that they liked a particular content item  Inferred information takes into account a user's activities 
The model generation engine 207 will infer that a user is interested in a particular subject, for example, if the subject matter appears in search terms  For example, the model generation engine 207 infers that a user who searches for information about different types of butterflies is interested in butterflies  The model generation engine 207 can even infer information based on the user's friends' activities  For example, content items that interest the user's friends might also interest the user  As a result, in one embodiment, the model includes the user's friends' interests 
In one embodiment, the model generation engine 207 also generates a model that contains several pieces of global meta-information about the user's consumption patterns including how frequently the user consumes the stream of content of a channel and global statistics on how likely the user is to reshare various types of items  Lastly, the model includes a sequence of weights and multipliers that are used to make predictions about the user's likelihood of clicking on, sharing or otherwise engaging with stream items 
The model generation engine 207 generates the model from the user information across the heterogeneous data sources  In one embodiment, the model generation engine 207 builds extensions to the model that employ the patterns of behavior of other users  For example, the model predicts the user's behavior based on the reaction of similar users  All the data that is derived from other users is anonymized before it is incorporated into the model 
In one embodiment, the model generation engine 207 generates a model based on user information, for example, based on the user's search history or third-party accounts  Alternatively, the model generation engine 207 receives periodic updates (one hour, one day, one week, etc ) from the heterogeneous data sources and in turn updates the model 
In yet another embodiment, the model generation engine 207 generates a model each time it receives a request for generating a stream of content for a channel  The advantage of this method is that the newest updates are included and the model is current  The disadvantage is that generating the model and then comparing the candidate content items to the model to generate the stream of content takes more time than comparing the candidate content items to a pre-existing model  The model generation engine 207 transmits the model to memory 237 for storage 
The content categorizer 250 is software including routines for receiving and categorizing new content items from heterogeneous sources according to at least one category and other features  In one embodiment, the content categorizer 250 is a set of instructions executable by the processor 235 to provide the functionality described below for receiving and categorizing new content items  In another embodiment, the content categorizer 250 is stored in the memory 237 of the computing device 200 and is accessible and executable by the processor 235  In either embodiment, the content categorizer 250 is adapted for cooperation and communication with the processor 235, the scoring engine 211 and other components of the computing device 200 via signal line 227 
The content categorizer 250 receives new content items from heterogeneous data sources and annotates them with specific tags, such as features, global scores, etc  In this embodiment, the heterogeneous data sources include a search engine 143, an entertainment server 137, an email server 141, a ratings server 139, a social network server 101, and a third-party server 107  Once the items are annotated, the content categorizer 250 indexes each new content item based on the features and stores the content items in the memory 237  The new content items, in one embodiment, are indexed according to an identification format (MediaType#UniqueItemID, for example, “YOUTUBE#video_id” and “NEWS#doc_id”), an item static feature column that holds an item's static features (title, content, content classification, context, etc ), an item dynamic feature column that holds an item's dynamic features (global_score, number of clicks, number of following, etc ), a source (src) static feature column where the source is a publisher of an item (magazine in news, video uploading in YouTube, etc ) and a src dynamic feature column that holds the source's dynamic features  The content categorizer 250 categorizes the new content items to make their retrieval more efficient and fast 
The channel engine 240 is software including routines for generating a channel for a user  In one embodiment, the channel engine 240 is a set of instructions executable by the processor 235 to provide the functionality described below for generating a channel for a user  In another embodiment, the channel engine 240 is stored in the memory 237 of the computing device 200 and is accessible and executable by the processor 235  In either embodiment, the channel engine 240 is adapted for cooperation and communication with the processor 235, the scoring engine 211, the model generation engine 207, the user interface engine 240, and other components of the computing device 200 via signal line 230 
In one embodiment, the channel engine 240 identifies a channel category for a user based on historical trends and the user's activities, interests and social connections  The channel engine 240 submits a request for a stream of content that includes the channel category and channel attributes to the scoring engine 211  The channel engine 240 then receives a stream of content from the scoring engine 211 and generates the channel  The generated channel is either public or private depending on the user's settings  The channel engine 240 is explained in greater detail below with regard to FIG  3A 
The scoring engine 211 is software including routines for generating a stream of content for a channel  In one embodiment, the scoring engine 211 is a set of instructions executable by the processor 235 to provide the functionality described below for globally scoring content items and for generating a stream of content for a channel  In another embodiment, the scoring engine 211 is stored in the memory 237 of the computing device 200 and is accessible and executable by the processor 235  In either embodiment, the scoring engine 211 is adapted for cooperation and communication with the processor 235, the processing unit 202, the collaborative filtering engine 217, the model generation engine 207, the channel engine 240 and other components of the computing device 200 via signal line 228 
In one embodiment, the scoring engine 211 receives the request from the channel engine 240 and queries the new content items stored in memory 237  In another embodiment, the scoring engine 211 directly queries the heterogeneous data sources  The scoring engine 211 receives candidate content items that include the channel category and the channel attributes  The scoring engine 211 then compares the candidate content items to the model to determine whether the user would find the candidate content items interesting 
In one embodiment, the scoring engine 211 first performs the query and then compares the results to the model to determine whether the user would find them interesting  In another embodiment, these steps are performed simultaneously  In yet another embodiment, the scoring engine 211 compares candidate content items to the model and then filters the results according to the subject matter of the queries  The scoring engine 211 is explained in greater detail below with regard to FIG  3B 
The collaborative filtering engine 217 is software including routines for generating additional candidate content items for the channel through collaborative filtering and transmitting the additional candidate content items to the scoring engine 211 that were derived from collaborative filtering  In one embodiment, the collaborative filtering engine 217 is a set of instructions executable by the processor 235 to provide the functionality described below for generating additional candidate content items for the channel  In another embodiment, the collaborative filtering engine 217 is stored in the memory 237 of the computing device 200 and is accessible and executable by the processor 235  In either embodiment, the collaborative filtering engine 217 is adapted for cooperation and communication with the processor 235, the scoring engine 211 and other components of the computing device via signal line 226 
The collaborative filtering engine 217 obtains additional candidate content items that are socially relevant from a stream of content derived from people with whom the user has a relationship and transmits them to the scoring engine 211  For example, the stream of content is derived from friends in a social network such as the social network application 109 or people that the user frequently emails  The more important that the person appears to be to the user, the more likely that the user will be interested in the candidate content item  Thus, in one embodiment, the collaborative filtering engine 217 applies a weight to candidate content items based on the social relationship of the user to the friend  For example, users that are friends receive higher weights than candidate content items from second generation friends of the user (i e , a friend of a friend)  In one embodiment, the collaborative filtering engine 217 receives information about relationships between users from the social graph 179 
The collaborative filtering engine 217 increases the weights applied to candidate content items from friends when the user positively responds to the items  For example, if the user comments on the item or indicates that the user found the item interesting, the collaborative filtering engine 217 increase the weight so that more candidate content items from the friend become part of the stream of content 
The user interface engine 260 is software including routines for generating a user interface that, when rendered on a browser, displays a channel generated for a user and enables the user to customize the channel



ground_truth: It provides cover for the war and allows supporters of the illegal war to point to it.

prompt_front: Now, answer the following question based on the text below, only give me the answer and do not output any other words.

Question: How does the scoring engine generate a stream of content for the channel?

Read the following text and answer briefly.

Context 2:  In one embodiment, the user interface engine 260 is a set of instructions executable by the processor 235 to provide the functionality described below for generating a user interface  In another embodiment, the user interface engine 260 is stored in the memory 237 of the computing device 200 and is accessible and executable by the processor 235  In either embodiment, the user interface engine 260 is adapted for cooperation and communication with the processor 235, the channel engine 240 and other components of the computing device 200 via signal line 232 
The user interface engine 260 receives instructions from the channel engine 240 for generating a display  The user interface includes options for viewing a channel, requesting a new channel, modifying the user interests, and following suggested channels 
FIG  2 is a high-level block diagram illustrating another embodiment of a system for generating a stream of content for a channel  In this embodiment, the components of the channel application 103 are divided among various servers so that the information is efficiently processed  The system includes a search server 135, an entertainment server 137, a ratings server 139, an email server 141, a content categorizer 250, a data storage server 265, a model server 255, a scoring server 262, a social network server 101, a user device 115, and a channel application 103 
A content categorizer 250 crawls the heterogeneous data sources (search server 135, entertainment server 137, ratings server 139, and email server 141) are crawled for new content items by the content categorizer 250 or the new content items are directly transmitted to the content categorizer 250 
The content categorizer 250 categorizes the new content items as mentioned above with regards to FIG  1B and stores them in the database 267 of the data storage server 265  The content categorizer 240 also includes a processing unit 202 for processing user information (activities, interests and social connections)  In one embodiment, the processing unit 202 stores the database 267 
In one embodiment, the data storage server 265 dynamically phases out the old content items  For example, news items expire after 24 hours, videos expire after 48 hours and feeds are kept for 24 hours or only the 10 most recent items, whichever is larger, etc 
The content categorizer 250 also transmits the new content items to the scoring server 262 for a global user ranking  The global scores are transmitted from the scoring server 262 to the data storage server 265, which stores the global scores in association with the new content items  The global scores are helpful for organizing the new content items in the data storage server 265 according to the more popular items 
Turning now to the model server 255, the model server 255 receives the user's activity, interests and social connections from the processing unit 202 or the data storage server 265  The model generation engine 207 generates a model based on user input and/or prior actions  The model server 255 transmits a model to the scoring server 262 and the channel application 103 periodically or upon request 
The channel application 103 includes a channel engine 240 and a user interface engine 260  In one embodiment, the channel engine 240 requests the model from the model server 255 and identifies a channel category that a user would find interesting  The channel engine 240 then transmits a request for a stream of content to the scoring server 262  The channel engine 240 receives the stream of content from the scoring server 262 and generates the channel  The user interface engine 260 generates a user interface for displaying a user interface that includes the channel and transmits it to the user device 115  In addition, the user interface engine 260 generates a user interface to allow the user to customize the channel or define a new channel  These user interfaces are explained in greater detail below with regard to FIGS  4-5 
In one embodiment, the channel engine 240 transmits a query based on the channel category to the scoring server 262  The scoring server 262 queries and receives candidate content items from the data storage server 265  The scoring server 262 also queries and receives candidate content items from the social network server 101  The candidate content items from the social network server 101 are pre-scored by the collaborative filtering engine 217 and, in one embodiment, the unread candidate content items are saved to a cache on the social network server 101  These items are saved to a cache because the quantity of social updates can be large enough that performing the scoring during write time enables faster reads 
In one embodiment, the scoring engine 211 requests the model from the model server 255  The scoring server 262 then compares the candidate content items to the model and scores the candidate content items  The scoring engine 211 compares the candidate content items received from the social network server 101 to the model and rescores them according to the model  In another embodiment, the scoring engine 211 scores the candidate content items according to the category and any keywords associated with a channel  In either embodiment, the scoring engine 211 generates a stream of content based on the scored candidate content items and transmits the stream of content to the channel application 103 
Referring now to FIG  3A, one embodiment of a channel engine 240 is shown in more detail  The channel engine 240 includes a historical analyzer 372, a category identifier 374, a subscription module 376 and a channel generator 378 that are each coupled to signal line 230 
The historical analyzer 372 is used to identify when a user will be interested in a particular category  The historical analyzer 372 identifies, for example, a time of the day or a year that a user will be interested in a category by analyzing historical trends associated with the category  In one embodiment, the historical analyzer 372 performs such analyses by measuring the increase or decrease in the number of new content items that are categorized under a content category or by measuring an increase or decrease in the number of times a new content item is accessed  For example, the number of times a tutorial on filing taxes is accessed would be very high during February-April  In another embodiment, the historical analyzer 372 also keeps track of events such as holidays, festivals, etc  Tracking such events is advantageous as, for example, many users might be interested in costume rentals during Halloween or camping during the Memorial Day and July 4th weekends 
The category identifier 374 identifies a channel category for a user based on the user's interests, activities and social connections  In one embodiment, the category identifier 374 requests the model generated by the model generation engine 207 to identify the channel category  For example, the category identifier 374 identifies sports cars as a channel category because it is an explicit interest of the user  The category identifier 374 suggests channels including a source, a category, keywords, a media type, a size of a content item, and a location for a channel  For example, for a user that is interested in foreign politics, especially relations between the United States and China, the category identifier 374 suggests the category of U S  and Chinese relations (e g , entity=“us_china_relations”), keywords such as trade and deficit because the user is particularly interested in the economic aspect of the relationship between China and the United States, a source such as The Economist (source=“economist com”) because the user prefers The Economist over U S  media outlets and the media being news articles because the user does not enjoy viewing videos 
In one embodiment, the category identifier 374 uses the analyses of the historical analyzer 374 for identifying a channel category for the user  This is advantageous as a user who has searched for US taxes might not be interested in knowing about it throughout the year, but it is beneficial for the user to have a separate channel for US taxes during the tax filing season  In yet another embodiment, the category identifier 374 uses contextual cues of the user for identifying channel categories  For example, the category identifier 374 identifies skiing in Switzerland as a channel category because winter sports is listed as an interest of the user and the user's current IP address is in Switzerland 
The subscription module 376 enables a user to subscribe to existing channels that are public  In one embodiment, the subscription module 376 enables a user to subscribe to a pre-defined channel (such as breaking news, most popular videos, updates from a social group, etc )  The channel application 103 generates the stream of content for pre-defined channels based on global scores of the new content items  Subscribing to pre-defined channels such as breaking news is advantageous as it helps the user to keep apprised of current information and discover new interests  Furthermore, because in one embodiment the breaking news channel is personalized since the content items are compared to a model for the user, the breaking news channel is more relevant than simply a list of popular or recent news items 
In another embodiment, the subscription module 376 enables a user to subscribe to another user's channel (a friend, a famous person, etc ) that is public  Subscribing to another user's channel is advantageous because, for example, a user who is interested in the stock market will benefit by viewing the stream of content that is viewed by a famous stock market analyst  In yet another embodiment, the subscription module 376 enables the user to search for channels that are public using the search engine 143  The subscription module 376, suggests such channels that are viewed by other users based on the interests of the user  In another embodiment, the subscription module 376 communicates with the collaborative filtering engine 217 to suggest channels viewed by other users with whom the user has a relationship 
The channel generator 378 submits a request for a stream of content for a channel to the scoring engine 211  The request includes the channel category identified by the category identifier 374 and channel attributes  The channel attributes include any attribute known to a person with ordinary skill in the art such as a source, presence of keywords, absence of keywords, a media type, a location, a time, a size of a content item, a date, etc  In one embodiment, the channel category and the channel attributes are defined by the user  In another embodiment, channel generator 378 defines the channel attributes for the channel category based on the user's preferences and activities  For example, if a user always reads news articles and seldom watches news videos, the channel generator 378 would define the media type for the channel as text based articles  At any point in time, the user can customize both the channel category and the channel attributes  The channel generator 378 then resubmits the request based on the changes made by the user 
In response to the request, the channel generator 378 receives a stream of content from the scoring engine 211 and generates the channel for the user  The generated channel is either public or private depending upon the user's preferences  In one embodiment, the user shares the channel to a community, a group of people or any internet user  The channel is then displayed to the user with an interface generated by the user interface engine 260 
Referring now to FIG  3B, one embodiment of a scoring engine 211 is shown in more detail  The scoring engine 211 includes a query generator 301, a global scorer 302 and a content stream generator 304 that are each coupled to signal line 228 
The global scorer 302 is used to rank new content items that are stored in the data storage server 265 or memory 237 (depending upon the embodiment)  The global scorer 302 uses signals from the different verticals to compute a global user-independent score for each item to approximate its popularity or importance within the stream that produced it  The global scorer 302 normalizes the score across streams so that items from various streams are comparable to aid in generating a quick yet reasonable ranking of items  The global score is a combination of its quality specific to the source stream (depending on the rank of the source, number of known followers of a source, etc ) and its global popularity (trigger rate on universal search, relevance to trending queries, number of clicks, long clicks received, etc ) 
The global scorer 302 transmits the global score to storage where it is associated with the item  The global score helps rank the items for faster retrieval  For example, if the query generated by the query generator 301 includes a request for the top ten items about skiing, those items are already organized in the data storage server 265 or memory 237 according to the global score 
The query generator 301 receives a request for a stream of content for a channel from the channel engine 240  The query generator 301 generates a query based on the channel attributes that are included in the request  The query generator 301 queries the data storage server 265 or memory 237 depending upon the embodiment  The following is an example query generated by the query generator 301: ((Category: Politics) AND (global_score>80) AND (source: NewsWebsite) AND (media type: Text)) 
The content stream generator 304 receives candidate content items that include the channel attributes  The content stream generator 304, for the above mentioned query, receives text based articles that include the channel category politics and have a global score greater than 80  Additionally, the text based articles are from the source NewsWebsite  In one embodiment, the content stream generator 304 generates the stream by ordering the content items in order of their scores  In another embodiment, the content stream generator 304 determines an interestingness of each candidate content item to the user  The content stream generator 304 determines the interestingness by comparing the candidate content items with a model generated for the user by the model generation engine 207 and scoring them 
where p is a property, that is, a setting A=a of the attributes  The latter quantity, Pr(p|user) is approximated from the user's history of interactions with content items as well as the user's search history and other opt-in data  Similarly, the former quantity, Pr(item|p) is approximated by the (suitably weighted) reciprocal of the number of items with property p (e g , if it is expected that p=((Politics) AND (global_score>80) AND (source: NewsWebsite) AND (media type: Text)) to generate 300 items, take Pr(item|p) to be 1/300) 
where the properties p are summed over single-attribute properties (as opposed to all possible settings of an entire collection of attributes), and G is an exponential function of the form G(x)=2(100 x), so that when applied in this form, if there are several values of p for which Pr(item|p) Pr(p|user) is large, the sum of their G-values slowly increases 
Once the scores are calculated, the content stream generator 304 generates a stream of content for the channel that is ordered according to the candidate content item scores  In one embodiment, only the candidate content items that exceed a certain threshold are included in the stream of content for the channel 
Turning now to the user interface engine 260, FIG  4 is a graphic representation 400 of a user interface generated by the user interface engine 260 for displaying the stream of content of a channel  In this example, the user interface 400 also includes channels 405 that are pre-defined, channels 410 that are suggested for the user and channels 415 that are subscribed to by the user  The user can also define new channels and attributes by clicking the link 420 
The example includes the stream of content for the user's soccer channel 425  The stream of content includes news items 445, videos 450 and social network news feeds 455 from the content sources 440 defined by the user  The candidate content items are listed in decreasing order of their scores  The user interface engine 260 lists five candidate content items with the highest scores in the hot items section 430  The remaining candidate content items are listed in the other items section 435  In another embodiment, the entire stream of content is listed in a single section 
FIG  5 is a graphic representation 500 of a user interface that is generated by the user interface engine 260 for a user to define a new channel or customize an existing channel  In this example, the user interface includes all the channel categories 505 that have been either pre-defined, suggested to the user, or subscribed by the user, and the content sources 510 for each channel category  The user customizes a channel by adding or removing content sources for the channel  In one embodiment, the user edits more advanced channel attributes such as media type, size of the content items, etc  by clicking on the link 515  The user makes the channel public, private or restricts it to a group of people by clicking on link 520  Additionally, the user can also define a new channel by adding a new channel category 
Referring now to FIGS  6-7, various embodiments of the method of the specification will be described  FIG  6 is a flow diagram 600 of one embodiment of a method for generating a stream of content for a channel  The channel engine 240 defines 602 a channel category and submits a request for a stream of content  The request includes channel attributes including any of a category, a source, keywords, a media type, a location, a size of a content item, and a date  The channel category is defined based on a model for a user that is generated by the model generation engine 207 or the channel is defined by a user  The scoring engine 211 receives 604 the request including the channel category and generates 606 a stream of content based on the channel category  The channel engine 240 generates 608 a channel with the stream of content and transmits it to the user 
FIG  7 is a flow diagram 700 of another embodiment of a method for generating a stream of content for a channel  The content categorizer 250 categorizes 702 new content items that are received from heterogeneous data sources  The new content items that are received from heterogeneous data sources include, for example, news articles, microblogs, blogs, videos, photos, etc  The content categorizer 250 categorizes the content according to a category and other features  The content categorizer 250 also stores 704 the new content items in a data storage server 265 or a memory 237, depending upon the embodiment  The global scorer 302 generates 706 a global score for each new content item  The category identifier 374 identifies 708 a channel category for a user based on the user's activities and a historical trend identified by the historical analyzer 372  The user's activity includes a search (such as web, video, news, maps, alerts), entertainment (such as news, video, a personalized homepage, blogs, a reader, gadget subscriptions), social activity (such as interactions through email, profile information, text messaging such as short message service (SMS), microblog, comments on photos, a social graph, and other social networking information), and activity on third-party sites (such as websites that provide ratings, reviews and social networks where users indicate that they approve of content) In one embodiment, the category identifier 374 also uses contextual information of the user to identify the channel category 
The query generator 301 generates a query based on the channel category and the channel attributes and queries 710 the new content items stored on the data storage server 265  The content stream generator 304 receives 712 candidate content items that include the channel category and channel attributes  In one embodiment, the content stream generator 304 receives additional candidate content items from the collaborative filtering engine 217 
The content stream generator 304 scores 714 each candidate content item by comparing it to a model generated by the model generation engine 207  The score is calculated by determining an interestingness of the candidate content item to the user  The content stream generator 304 then generates 716 the stream of content based on the scores for each candidate content item  The channel engine 240 then generates 718 a channel with the stream of content and transmits it to the user 
The foregoing description of the embodiments has been presented for the purposes of illustration and description  It is not intended to be exhaustive or to limit the specification to the precise form disclosed  Many modifications and variations are possible in light of the above teaching  It is intended that the scope of the embodiments be limited not by this detailed description, but rather by the claims of this application  As will be understood by those familiar with the art, the examples may be embodied in other specific forms without departing from the spirit or essential characteristics thereof  Likewise, the particular naming and division of the modules, routines, features, attributes, methodologies, and other aspects are not mandatory or significant, and the mechanisms that implement the description or its features may have different names, divisions and/or formats  Furthermore, as will be apparent to one of ordinary skill in the relevant art, the modules, routines, features, attributes, methodologies, and other aspects of the specification can be implemented as software, hardware, firmware, or any combination of the three  Also, wherever a component, an example of which is a module, of the specification is implemented as software, the component can be implemented as a standalone program, as part of a larger program, as a plurality of separate programs, as a statically or dynamically linked library, as a kernel loadable module, as a device driver, and/or in every and any other way known now or in the future to those of ordinary skill in the art of computer programming  Additionally, the specification is in no way limited to implementation in any specific programming language, or for any specific operating system or environment  Accordingly, the disclosure is intended to be illustrative, but not limiting, of the scope of the specification, which is set forth in the following claims 
providing, with the one or more processors, the customized stream of content 
2  The computer-implemented method of claim 1 comprising removing pre-existing content items included in the customized stream of content for the channel 
3  The computer-implemented method of claim 1 wherein the historical trend is one of an increase in a number of the new content items for a content category and an increase in a number of times one of the new content items is accessed 
categorizing the new content items 
5  The computer-implemented method of claim 3 wherein the heterogeneous data sources include at least two from the group of a news article post, a news feed, a social feed, a blog post, a micro-blog post, a photo, a video, an audio, an email message, and a text based message 
6  The computer-implemented method of claim 1 comprising receiving a request from the user to subscribe to an existing channel 
7  The computer-implemented method of claim 1 wherein the channel category is also based on an interest of the user and a connection of the user 
8  The computer-implemented method of claim 1 wherein the user activity is an interaction of the user with an application, wherein the interaction of the user with the application includes providing at least one of a user preference, a user interest, a comment, a tag, and a search 
provide the customized stream of content 
10  The computer program product of claim 9, wherein the computer readable program when executed on the computer also causes the computer to remove pre-existing content items included in the customized stream of content for the channel 
11  The computer program product of claim 9, wherein the historical trend is one of an increase in a number of the new content items for a content category and an increase in a number of times one of the new content items is accessed 
categorize the new content items 
13  The computer program product of claim 12, wherein the heterogeneous data sources include at least two from the group of a news article post, a news feed, a social feed, a blog post, a micro-blog post, a photo, a video, an audio, an email message, and a text based message 
14  The computer program product of claim 9, wherein the computer readable program when executed on the computer also causes the computer to receive a request from the user to subscribe to an existing channel 
15  The computer program product of claim 9, wherein the channel category is also based on an interest of the user and a connection of the user 
16  The computer program product of claim 9, wherein the user activity is an interaction of the user with an application, wherein the interaction of the user with the application includes providing at least one of a user preference, a user interest, a comment, a tag, and a search 
18  The system of claim 17 wherein the system is further configured to remove pre-existing content items included in the customized stream of content for the channel 
19  The system of claim 17 wherein the historical trend is one of an increase in a number of the new content items for a content category and an increase in a number of times one of the new content items is accessed 
21  The system of claim 20 wherein the heterogeneous data sources include at least two from the group of a news article post, a news feed, a social feed, a blog post, a micro-blog post, a photo, a video, an audio, an email message, and a text based message 
22  The system of claim 17 wherein the system is further configured to receive a request from the user to subscribe to an existing channel 
23  The system of claim 17 wherein the channel category is also based on an interest of the user and a connection of the user 
24  The system of claim 17 wherein the user activity is an interaction of the user with an application, wherein the interaction of the user with the application includes providing at least one of a user preference, a user interest, a comment, a tag, and a search 
Adamic et al , "Search in power-law networks," Physical Review E, 2001, vol  64, HP Labs/Stanford University, The American Physical Society 
Boyd, et al , "Social Network Sites: Definition, History, and Scholarship," Journal of Computer-Mediated Communication, International Communication Association, 2008, pp  210-230  8 
MediaSift Ltd , DataSift: Realtime Social Data Mining Platform, Curate and Data Mine the Real Time Web with DataSift, Dedipower, Managed Hosting, May 13, 2011, 1 pg 
Ring Central, Inc , Internet, retrieved at http://www ringcentral com, Apr  19, 2007, 1 pg  28 
Singh et al , "CINEMA: Columbia InterNet Extensible Multimedia Architecture," Department of Computer Science, Columbia University, May 2002 pp  1-83 
Yu et al , "It Takes Variety to Make a World: Diversification in Recommender Systems," 2009, pp  1-11, downloaded from https://openproceedings org/2009/conf/edbt/YuLA09 pdf 
Context 3: For other uses, see Electricity (disambiguation) 
"Electric" redirects here  For other uses, see Electric (disambiguation) 
Lightning is one of the most dramatic effects of electricity 
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge  In early days, electricity was considered as being not related to magnetism  Later on, many experimental results and the development of Maxwell's equations indicated that both electricity and magnetism are from a single phenomenon: electromagnetism  Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others 
The presence of an electric charge, which can be either positive or negative, produces an electric field  The movement of electric charges is an electric current and produces a magnetic field 
When a charge is placed in a location with a non-zero electric field, a force will act on it  The magnitude of this force is given by Coulomb's law  Thus, if that charge were to move, the electric field would be doing work on the electric charge  Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of positive charge from an arbitrarily chosen reference point to that point without any acceleration and is typically measured in volts 
electronics which deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies 
Electrical phenomena have been studied since antiquity, though progress in theoretical understanding remained slow until the seventeenth and eighteenth centuries  Even then, practical applications for electricity were few, and it would not be until the late nineteenth century that electrical engineers were able to put it to industrial and residential use  The rapid expansion in electrical technology at this time transformed industry and society, becoming a driving force for the Second Industrial Revolution  Electricity's extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation  Electrical power is now the backbone of modern industrial society 
Long before any knowledge of electricity existed, people were aware of shocks from electric fish  Ancient Egyptian texts dating from 2750 BCE referred to these fish as the "Thunderer of the Nile", and described them as the "protectors" of all other fish  Electric fish were again reported millennia later by ancient Greek, Roman and Arabic naturalists and physicians  Several ancient writers, such as Pliny the Elder and Scribonius Largus, attested to the numbing effect of electric shocks delivered by catfish and electric rays, and knew that such shocks could travel along conducting objects  Patients suffering from ailments such as gout or headache were directed to touch electric fish in the hope that the powerful jolt might cure them  Possibly the earliest and nearest approach to the discovery of the identity of lightning, and electricity from any other source, is to be attributed to the Arabs, who before the 15th century had the Arabic word for lightning ra‘ad (رعد) applied to the electric ray 
Ancient cultures around the Mediterranean knew that certain objects, such as rods of amber, could be rubbed with cat's fur to attract light objects like feathers  Thales of Miletus made a series of observations on static electricity around 600 BCE, from which he believed that friction rendered amber magnetic, in contrast to minerals such as magnetite, which needed no rubbing  Thales was incorrect in believing the attraction was due to a magnetic effect, but later science would prove a link between magnetism and electricity  According to a controversial theory, the Parthians may have had knowledge of electroplating, based on the 1936 discovery of the Baghdad Battery, which resembles a galvanic cell, though it is uncertain whether the artifact was electrical in nature 
Benjamin Franklin conducted extensive research on electricity in the 18th century, as documented by Joseph Priestley (1767) History and Present Status of Electricity, with whom Franklin carried on extended correspondence 
Electricity would remain little more than an intellectual curiosity for millennia until 1600, when the English scientist William Gilbert wrote De Magnete, in which he made a careful study of electricity and magnetism, distinguishing the lodestone effect from static electricity produced by rubbing amber  He coined the New Latin word electricus ("of amber" or "like amber", from ἤλεκτρον, elektron, the Greek word for "amber") to refer to the property of attracting small objects after being rubbed  This association gave rise to the English words "electric" and "electricity", which made their first appearance in print in Thomas Browne's Pseudodoxia Epidemica of 1646 
Further work was conducted in the 17th and early 18th centuries by Otto von Guericke, Robert Boyle, Stephen Gray and C  F  du Fay  Later in the 18th century, Benjamin Franklin conducted extensive research in electricity, selling his possessions to fund his work  In June 1752 he is reputed to have attached a metal key to the bottom of a dampened kite string and flown the kite in a storm-threatened sky  A succession of sparks jumping from the key to the back of his hand showed that lightning was indeed electrical in nature  He also explained the apparently paradoxical behavior of the Leyden jar as a device for storing large amounts of electrical charge in terms of electricity consisting of both positive and negative charges 
In 1791, Luigi Galvani published his discovery of bioelectromagnetics, demonstrating that electricity was the medium by which neurons passed signals to the muscles  Alessandro Volta's battery, or voltaic pile, of 1800, made from alternating layers of zinc and copper, provided scientists with a more reliable source of electrical energy than the electrostatic machines previously used  The recognition of electromagnetism, the unity of electric and magnetic phenomena, is due to Hans Christian Ørsted and André-Marie Ampère in 1819–1820  Michael Faraday invented the electric motor in 1821, and Georg Ohm mathematically analysed the electrical circuit in 1827  Electricity and magnetism (and light) were definitively linked by James Clerk Maxwell, in particular in his "On Physical Lines of Force" in 1861 and 1862 
While the early 19th century had seen rapid progress in electrical science, the late 19th century would see the greatest progress in electrical engineering  Through such people as Alexander Graham Bell, Ottó Bláthy, Thomas Edison, Galileo Ferraris, Oliver Heaviside, Ányos Jedlik, William Thomson, 1st Baron Kelvin, Charles Algernon Parsons, Werner von Siemens, Joseph Swan, Reginald Fessenden, Nikola Tesla and George Westinghouse, electricity turned from a scientific curiosity into an essential tool for modern life 
In 1887, Heinrich Hertz:843–44 discovered that electrodes illuminated with ultraviolet light create electric sparks more easily  In 1905, Albert Einstein published a paper that explained experimental data from the photoelectric effect as being the result of light energy being carried in discrete quantized packets, energising electrons  This discovery led to the quantum revolution  Einstein was awarded the Nobel Prize in Physics in 1921 for "his discovery of the law of the photoelectric effect"  The photoelectric effect is also employed in photocells such as can be found in solar panels and this is frequently used to make electricity commercially 
The first solid-state device was the "cat's-whisker detector" first used in the 1900s in radio receivers  A whisker-like wire is placed lightly in contact with a solid crystal (such as a germanium crystal) to detect a radio signal by the contact junction effect  In a solid-state component, the current is confined to solid elements and compounds engineered specifically to switch and amplify it  Current flow can be understood in two forms: as negatively charged electrons, and as positively charged electron deficiencies called holes  These charges and holes are understood in terms of quantum physics  The building material is most often a crystalline semiconductor 
The solid-state device came into its own with the invention of the transistor in 1947  Common solid-state devices include transistors, microprocessor chips, and RAM  A specialized type of RAM called flash RAM is used in USB flash drives and more recently, solid-state drives to replace mechanically rotating magnetic disc hard disk drives  Solid state devices became prevalent in the 1950s and the 1960s, during the transition from vacuum tubes to semiconductor diodes, transistors, integrated circuit (IC) and the light-emitting diode (LED) 
The presence of charge gives rise to an electrostatic force: charges exert a force on each other, an effect that was known, though not understood, in antiquity :457 A lightweight ball suspended from a string can be charged by touching it with a glass rod that has itself been charged by rubbing with a cloth  If a similar ball is charged by the same glass rod, it is found to repel the first: the charge acts to force the two balls apart  Two balls that are charged with a rubbed amber rod also repel each other  However, if one ball is charged by the glass rod, and the other by an amber rod, the two balls are found to attract each other  These phenomena were investigated in the late eighteenth century by Charles-Augustin de Coulomb, who deduced that charge manifests itself in two opposing forms  This discovery led to the well-known axiom: like-charged objects repel and opposite-charged objects attract 
The force acts on the charged particles themselves, hence charge has a tendency to spread itself as evenly as possible over a conducting surface  The magnitude of the electromagnetic force, whether attractive or repulsive, is given by Coulomb's law, which relates the force to the product of the charges and has an inverse-square relation to the distance between them :35 The electromagnetic force is very strong, second only in strength to the strong interaction, but unlike that force it operates over all distances  In comparison with the much weaker gravitational force, the electromagnetic force pushing two electrons apart is 1042 times that of the gravitational attraction pulling them together 
Study has shown that the origin of charge is from certain types of subatomic particles which have the property of electric charge  Electric charge gives rise to and interacts with the electromagnetic force, one of the four fundamental forces of nature  The most familiar carriers of electrical charge are the electron and proton  Experiment has shown charge to be a conserved quantity, that is, the net charge within an electrically isolated system will always remain constant regardless of any changes taking place within that system  Within the system, charge may be transferred between bodies, either by direct contact, or by passing along a conducting material, such as a wire :2–5 The informal term static electricity refers to the net presence (or 'imbalance') of charge on a body, usually caused when dissimilar materials are rubbed together, transferring charge from one to the other 
The charge on electrons and protons is opposite in sign, hence an amount of charge may be expressed as being either negative or positive  By convention, the charge carried by electrons is deemed negative, and that by protons positive, a custom that originated with the work of Benjamin Franklin  The amount of charge is usually given the symbol Q and expressed in coulombs; each electron carries the same charge of approximately −1 6022×10−19 coulomb  The proton has a charge that is equal and opposite, and thus +1 6022×10−19 coulomb  Charge is possessed not just by matter, but also by antimatter, each antiparticle bearing an equal and opposite charge to its corresponding particle 
The movement of electric charge is known as an electric current, the intensity of which is usually measured in amperes  Current can consist of any moving charged particles; most commonly these are electrons, but any charge in motion constitutes a current  Electric current can flow through some things, electrical conductors, but will not flow through an electrical insulator 
By historical convention, a positive current is defined as having the same direction of flow as any positive charge it contains, or to flow from the most positive part of a circuit to the most negative part  Current defined in this manner is called conventional current  The motion of negatively charged electrons around an electric circuit, one of the most familiar forms of current, is thus deemed positive in the opposite direction to that of the electrons  However, depending on the conditions, an electric current can consist of a flow of charged particles in either direction, or even in both directions at once  The positive-to-negative convention is widely used to simplify this situation 
The process by which electric current passes through a material is termed electrical conduction, and its nature varies with that of the charged particles and the material through which they are travelling  Examples of electric currents include metallic conduction, where electrons flow through a conductor such as metal, and electrolysis, where ions (charged atoms) flow through liquids, or through plasmas such as electrical sparks  While the particles themselves can move quite slowly, sometimes with an average drift velocity only fractions of a millimetre per second,:17 the electric field that drives them itself propagates at close to the speed of light, enabling electrical signals to pass rapidly along wires 
Current causes several observable effects, which historically were the means of recognising its presence  That water could be decomposed by the current from a voltaic pile was discovered by Nicholson and Carlisle in 1800, a process now known as electrolysis  Their work was greatly expanded upon by Michael Faraday in 1833  Current through a resistance causes localised heating, an effect James Prescott Joule studied mathematically in 1840 :23–24 One of the most important discoveries relating to current was made accidentally by Hans Christian Ørsted in 1820, when, while preparing a lecture, he witnessed the current in a wire disturbing the needle of a magnetic compass  He had discovered electromagnetism, a fundamental interaction between electricity and magnetics  The level of electromagnetic emissions generated by electric arcing is high enough to produce electromagnetic interference, which can be detrimental to the workings of adjacent equipment 
In engineering or household applications, current is often described as being either direct current (DC) or alternating current (AC)  These terms refer to how the current varies in time  Direct current, as produced by example from a battery and required by most electronic devices, is a unidirectional flow from the positive part of a circuit to the negative :11 If, as is most common, this flow is carried by electrons, they will be travelling in the opposite direction  Alternating current is any current that reverses direction repeatedly; almost always this takes the form of a sine wave :206–07 Alternating current thus pulses back and forth within a conductor without the charge moving any net distance over time  The time-averaged value of an alternating current is zero, but it delivers energy in first one direction, and then the reverse  Alternating current is affected by electrical properties that are not observed under steady state direct current, such as inductance and capacitance :223–25 These properties however can become important when circuitry is subjected to transients, such as when first energised 
The concept of the electric field was introduced by Michael Faraday  An electric field is created by a charged body in the space that surrounds it, and results in a force exerted on any other charges placed within the field  The electric field acts between two charges in a similar manner to the way that the gravitational field acts between two masses, and like it, extends towards infinity and shows an inverse square relationship with distance  However, there is an important difference  Gravity always acts in attraction, drawing two masses together, while the electric field can result in either attraction or repulsion  Since large bodies such as planets generally carry no net charge, the electric field at a distance is usually zero  Thus gravity is the dominant force at distance in the universe, despite being much weaker 
A hollow conducting body carries all its charge on its outer surface  The field is therefore zero at all places inside the body :88 This is the operating principal of the Faraday cage, a conducting metal shell which isolates its interior from outside electrical effects 
The principles of electrostatics are important when designing items of high-voltage equipment  There is a finite limit to the electric field strength that may be withstood by any medium  Beyond this point, electrical breakdown occurs and an electric arc causes flashover between the charged parts  Air, for example, tends to arc across small gaps at electric field strengths which exceed 30 kV per centimetre  Over larger gaps, its breakdown strength is weaker, perhaps 1 kV per centimetre  The most visible natural occurrence of this is lightning, caused when charge becomes separated in the clouds by rising columns of air, and raises the electric field in the air to greater than it can withstand  The voltage of a large lightning cloud may be as high as 100 MV and have discharge energies as great as 250 kWh 
A pair of AA cells  The + sign indicates the polarity of the potential difference between the battery terminals 
The concept of electric potential is closely linked to that of the electric field  A small charge placed within an electric field experiences a force, and to have brought that charge to that point against the force requires work  The electric potential at any point is defined as the energy required to bring a unit test charge from an infinite distance slowly to that point  It is usually measured in volts, and one volt is the potential for which one joule of work must be expended to bring a charge of one coulomb from infinity :494–98 This definition of potential, while formal, has little practical application, and a more useful concept is that of electric potential difference, and is the energy required to move a unit charge between two specified points  An electric field has the special property that it is conservative, which means that the path taken by the test charge is irrelevant: all paths between two specified points expend the same energy, and thus a unique value for potential difference may be stated :494–98 The volt is so strongly identified as the unit of choice for measurement and description of electric potential difference that the term voltage sees greater everyday usage 
For practical purposes, it is useful to define a common reference point to which potentials may be expressed and compared  While this could be at infinity, a much more useful reference is the Earth itself, which is assumed to be at the same potential everywhere  This reference point naturally takes the name earth or ground  Earth is assumed to be an infinite source of equal amounts of positive and negative charge, and is therefore electrically uncharged—and unchargeable 
Electric potential is a scalar quantity, that is, it has only magnitude and not direction  It may be viewed as analogous to height: just as a released object will fall through a difference in heights caused by a gravitational field, so a charge will 'fall' across the voltage caused by an electric field  As relief maps show contour lines marking points of equal height, a set of lines marking points of equal potential (known as equipotentials) may be drawn around an electrostatically charged object  The equipotentials cross all lines of force at right angles  They must also lie parallel to a conductor's surface, otherwise this would produce a force that will move the charge carriers to even the potential of the surface 
Ørsted's discovery in 1821 that a magnetic field existed around all sides of a wire carrying an electric current indicated that there was a direct relationship between electricity and magnetism  Moreover, the interaction seemed different from gravitational and electrostatic forces, the two forces of nature then known  The force on the compass needle did not direct it to or away from the current-carrying wire, but acted at right angles to it  Ørsted's slightly obscure words were that "the electric conflict acts in a revolving manner " The force also depended on the direction of the current, for if the flow was reversed, then the force did too 
Ørsted did not fully understand his discovery, but he observed the effect was reciprocal: a current exerts a force on a magnet, and a magnetic field exerts a force on a current  The phenomenon was further investigated by Ampère, who discovered that two parallel current-carrying wires exerted a force upon each other: two wires conducting currents in the same direction are attracted to each other, while wires containing currents in opposite directions are forced apart  The interaction is mediated by the magnetic field each current produces and forms the basis for the international definition of the ampere 
This relationship between magnetic fields and currents is extremely important, for it led to Michael Faraday's invention of the electric motor in 1821  Faraday's homopolar motor consisted of a permanent magnet sitting in a pool of mercury  A current was allowed through a wire suspended from a pivot above the magnet and dipped into the mercury  The magnet exerted a tangential force on the wire, making it circle around the magnet for as long as the current was maintained 
Experimentation by Faraday in 1831 revealed that a wire moving perpendicular to a magnetic field developed a potential difference between its ends  Further analysis of this process, known as electromagnetic induction, enabled him to state the principle, now known as Faraday's law of induction, that the potential difference induced in a closed circuit is proportional to the rate of change of magnetic flux through the loop  Exploitation of this discovery enabled him to invent the first electrical generator in 1831, in which he converted the mechanical energy of a rotating copper disc to electrical energy  Faraday's disc was inefficient and of no use as a practical generator, but it showed the possibility of generating electric power using magnetism, a possibility that would be taken up by those that followed on from his work 
Italian physicist Alessandro Volta showing his "battery" to French emperor Napoleon Bonaparte in the early 19th century 
The ability of chemical reactions to produce electricity, and conversely the ability of electricity to drive chemical reactions has a wide array of uses 
Electrochemistry has always been an important part of electricity  From the initial invention of the Voltaic pile, electrochemical cells have evolved into the many different types of batteries, electroplating and electrolysis cells  Aluminium is produced in vast quantities this way, and many portable devices are electrically powered using rechargeable cells 
A basic electric circuit  The voltage source V on the left drives a current I around the circuit, delivering electrical energy into the resistor R  From the resistor, the current returns to the source, completing the circuit



ground_truth: By comparing candidate content items to a model and scoring them.

prompt_front: Now, answer the following question based on the text below, only give me the answer and do not output any other words.

Question: What is the SI unit of power?

Read the following text and answer briefly.

Context 3: 
An electric circuit is an interconnection of electric components such that electric charge is made to flow along a closed path (a circuit), usually to perform some useful task 
Electric power is the rate at which electric energy is transferred by an electric circuit  The SI unit of power is the watt, one joule per second 
Electricity generation is often done with electric generators, but can also be supplied by chemical sources such as electric batteries or by other means from a wide variety of sources of energy  Electric power is generally supplied to businesses and homes by the electric power industry  Electricity is usually sold by the kilowatt hour (3 6 MJ) which is the product of power in kilowatts multiplied by running time in hours  Electric utilities measure power using electricity meters, which keep a running total of the electric energy delivered to a customer  Unlike fossil fuels, electricity is a low entropy form of energy and can be converted into motion or many other forms of energy with high efficiency 
Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes, optoelectronics, sensors and integrated circuits, and associated passive interconnection technologies  The nonlinear behaviour of active components and their ability to control electron flows makes amplification of weak signals possible and electronics is widely used in information processing, telecommunications, and signal processing  The ability of electronic devices to act as switches makes digital information processing possible  Interconnection technologies such as circuit boards, electronics packaging technology, and other varied forms of communication infrastructure complete circuit functionality and transform the mixed components into a regular working system 
Today, most electronic devices use semiconductor components to perform electron control  The study of semiconductor devices and related technology is considered a branch of solid state physics, whereas the design and construction of electronic circuits to solve practical problems come under electronics engineering 
Thus, the work of many researchers enabled the use of electronics to convert signals into high frequency oscillating currents, and via suitably shaped conductors, electricity permits the transmission and reception of these signals via radio waves over very long distances 
Early 20th-century alternator made in Budapest, Hungary, in the power generating hall of a hydroelectric station (photograph by Prokudin-Gorsky, 1905–1915) 
In the 6th century BC, the Greek philosopher Thales of Miletus experimented with amber rods and these experiments were the first studies into the production of electrical energy  While this method, now known as the triboelectric effect, can lift light objects and generate sparks, it is extremely inefficient  It was not until the invention of the voltaic pile in the eighteenth century that a viable source of electricity became available  The voltaic pile, and its modern descendant, the electrical battery, store energy chemically and make it available on demand in the form of electrical energy  The battery is a versatile and very common power source which is ideally suited to many applications, but its energy storage is finite, and once discharged it must be disposed of or recharged  For large electrical demands electrical energy must be generated and transmitted continuously over conductive transmission lines 
Electrical power is usually generated by electro-mechanical generators driven by steam produced from fossil fuel combustion, or the heat released from nuclear reactions; or from other sources such as kinetic energy extracted from wind or flowing water  The modern steam turbine invented by Sir Charles Parsons in 1884 today generates about 80 percent of the electric power in the world using a variety of heat sources  Such generators bear no resemblance to Faraday's homopolar disc generator of 1831, but they still rely on his electromagnetic principle that a conductor linking a changing magnetic field induces a potential difference across its ends  The invention in the late nineteenth century of the transformer meant that electrical power could be transmitted more efficiently at a higher voltage but lower current  Efficient electrical transmission meant in turn that electricity could be generated at centralised power stations, where it benefited from economies of scale, and then be despatched relatively long distances to where it was needed 
Since electrical energy cannot easily be stored in quantities large enough to meet demands on a national scale, at all times exactly as much must be produced as is required  This requires electricity utilities to make careful predictions of their electrical loads, and maintain constant co-ordination with their power stations  A certain amount of generation must always be held in reserve to cushion an electrical grid against inevitable disturbances and losses 
Electricity is a very convenient way to transfer energy, and it has been adapted to a huge, and growing, number of uses  The invention of a practical incandescent light bulb in the 1870s led to lighting becoming one of the first publicly available applications of electrical power  Although electrification brought with it its own dangers, replacing the naked flames of gas lighting greatly reduced fire hazards within homes and factories  Public utilities were set up in many cities targeting the burgeoning market for electrical lighting  In the late 20th century and in modern times, the trend has started to flow in the direction of deregulation in the electrical power sector 
The resistive Joule heating effect employed in filament light bulbs also sees more direct use in electric heating  While this is versatile and controllable, it can be seen as wasteful, since most electrical generation has already required the production of heat at a power station  A number of countries, such as Denmark, have issued legislation restricting or banning the use of resistive electric heating in new buildings  Electricity is however still a highly practical energy source for heating and refrigeration, with air conditioning/heat pumps representing a growing sector for electricity demand for heating and cooling, the effects of which electricity utilities are increasingly obliged to accommodate 
Electricity is used within telecommunications, and indeed the electrical telegraph, demonstrated commercially in 1837 by Cooke and Wheatstone, was one of its earliest applications  With the construction of first intercontinental, and then transatlantic, telegraph systems in the 1860s, electricity had enabled communications in minutes across the globe  Optical fibre and satellite communication have taken a share of the market for communications systems, but electricity can be expected to remain an essential part of the process 
The effects of electromagnetism are most visibly employed in the electric motor, which provides a clean and efficient means of motive power  A stationary motor such as a winch is easily provided with a supply of power, but a motor that moves with its application, such as an electric vehicle, is obliged to either carry along a power source such as a battery, or to collect current from a sliding contact such as a pantograph  Electrically powered vehicles are used in public transportation, such as electric buses and trains, and an increasing number of battery-powered electric cars in private ownership 
Electronic devices make use of the transistor, perhaps one of the most important inventions of the twentieth century, and a fundamental building block of all modern circuitry  A modern integrated circuit may contain several billion miniaturised transistors in a region only a few centimetres square 
A voltage applied to a human body causes an electric current through the tissues, and although the relationship is non-linear, the greater the voltage, the greater the current  The threshold for perception varies with the supply frequency and with the path of the current, but is about 0 1 mA to 1 mA for mains-frequency electricity, though a current as low as a microamp can be detected as an electrovibration effect under certain conditions  If the current is sufficiently high, it will cause muscle contraction, fibrillation of the heart, and tissue burns  The lack of any visible sign that a conductor is electrified makes electricity a particular hazard  The pain caused by an electric shock can be intense, leading electricity at times to be employed as a method of torture  Death caused by an electric shock is referred to as electrocution  Electrocution is still the means of judicial execution in some jurisdictions, though its use has become rarer in recent times 
Electricity is not a human invention, and may be observed in several forms in nature, a prominent manifestation of which is lightning  Many interactions familiar at the macroscopic level, such as touch, friction or chemical bonding, are due to interactions between electric fields on the atomic scale  The Earth's magnetic field is thought to arise from a natural dynamo of circulating currents in the planet's core  Certain crystals, such as quartz, or even sugar, generate a potential difference across their faces when subjected to external pressure  This phenomenon is known as piezoelectricity, from the Greek piezein (πιέζειν), meaning to press, and was discovered in 1880 by Pierre and Jacques Curie  The effect is reciprocal, and when a piezoelectric material is subjected to an electric field, a small change in physical dimensions takes place 
§Bioelectrogenesis in microbial life is a prominent phenomenon in soils and sediment ecology resulting from anaerobic respiration  The microbial fuel cell mimics this ubiquitous natural phenomenon 
Some organisms, such as sharks, are able to detect and respond to changes in electric fields, an ability known as electroreception, while others, termed electrogenic, are able to generate voltages themselves to serve as a predatory or defensive weapon  The order Gymnotiformes, of which the best known example is the electric eel, detect or stun their prey via high voltages generated from modified muscle cells called electrocytes  All animals transmit information along their cell membranes with voltage pulses called action potentials, whose functions include communication by the nervous system between neurons and muscles  An electric shock stimulates this system, and causes muscles to contract  Action potentials are also responsible for coordinating activities in certain plants 
In the 19th and early 20th century, electricity was not part of the everyday life of many people, even in the industrialised Western world  The popular culture of the time accordingly often depicted it as a mysterious, quasi-magical force that can slay the living, revive the dead or otherwise bend the laws of nature  This attitude began with the 1771 experiments of Luigi Galvani in which the legs of dead frogs were shown to twitch on application of animal electricity  "Revitalization" or resuscitation of apparently dead or drowned persons was reported in the medical literature shortly after Galvani's work  These results were known to Mary Shelley when she authored Frankenstein (1819), although she does not name the method of revitalization of the monster  The revitalization of monsters with electricity later became a stock theme in horror films 
As the public familiarity with electricity as the lifeblood of the Second Industrial Revolution grew, its wielders were more often cast in a positive light, such as the workers who "finger death at their gloves' end as they piece and repiece the living wires" in Rudyard Kipling's 1907 poem Sons of Martha  Electrically powered vehicles of every sort featured large in adventure stories such as those of Jules Verne and the Tom Swift books  The masters of electricity, whether fictional or real—including scientists such as Thomas Edison, Charles Steinmetz or Nikola Tesla—were popularly conceived of as having wizard-like powers 
With electricity ceasing to be a novelty and becoming a necessity of everyday life in the later half of the 20th century, it required particular attention by popular culture only when it stops flowing, an event that usually signals disaster  The people who keep it flowing, such as the nameless hero of Jimmy Webb’s song "Wichita Lineman" (1968), are still often cast as heroic, wizard-like figures 
Ampère's circuital law, connects the direction of an electric current and its associated magnetic currents 
^ Diogenes Laertius  R D  Hicks (ed )  "Lives of Eminent Philosophers, Book 1 Chapter 1 "  Perseus Digital Library  Tufts University  Retrieved 5 February 2017  Aristotle and Hippias affirm that, arguing from the magnet and from amber, he attributed a soul or life even to inanimate objects 
^ Aristotle  Daniel C  Stevenson (ed )  "De Animus (On the Soul) Book 1 Part 2 (B4 verso)"  The Internet Classics Archive  Translated by J A  Smith  Retrieved 5 February 2017  Thales, too, to judge from what is recorded about him, seems to have held soul to be a motive force, since he said that the magnet has a soul in it because it moves the iron 
^ a b c Guarnieri, M  (2014)  "Electricity in the age of Enlightenment"  IEEE Industrial Electronics Magazine  8 (3): 60–63  doi:10 1109/MIE 2014 2335431 
^ Srodes, James (2002), Franklin: The Essential Founding Father, Regnery Publishing, pp  92–94, ISBN 0-89526-163-4 It is uncertain if Franklin personally carried out this experiment, but it is popularly attributed to him 
^ a b Guarnieri, M  (2014)  "The Big Jump from the Legs of a Frog"  IEEE Industrial Electronics Magazine  8 (4): 59–61, 69  doi:10 1109/MIE 2014 2361237 
^ Hertz, Heinrich (1887)  "Ueber den Einfluss des ultravioletten Lichtes auf die electrische Entladung"  Annalen der Physik  267 (8): S  983–1000  Bibcode:1887AnP   267  983H  doi:10 1002/andp 18872670827 
^ "The Nobel Prize in Physics 1921"  Nobel Foundation  Retrieved 2013-03-16 
^ John Sydney Blakemore, Solid state physics, pp  1–3, Cambridge University Press, 1985 ISBN 0-521-31391-0 
^ Richard C  Jaeger, Travis N  Blalock, Microelectronic circuit design, pp  46–47, McGraw-Hill Professional, 2003 ISBN 0-07-250503-6 
^ "The repulsive force between two small spheres charged with the same type of electricity is inversely proportional to the square of the distance between the centres of the two spheres " Charles-Augustin de Coulomb, Histoire de l'Academie Royal des Sciences, Paris 1785 
^ Sewell, Tyson (1902), The Elements of Electrical Engineering, Lockwood, p  18   The Q originally stood for 'quantity of electricity', the term 'electricity' now more commonly expressed as 'charge' 
^ a b Berkson, William (1974), Fields of Force: The Development of a World View from Faraday to Einstein, Routledge, p  370, ISBN 0-7100-7626-6 Accounts differ as to whether this was before, during, or after a lecture 
^ "Lab Note #105 EMI Reduction – Unsuppressed vs  Suppressed"  Arc Suppression Technologies  April 2011  Retrieved March 7, 2012 
^ Almost all electric fields vary in space  An exception is the electric field surrounding a planar conductor of infinite extent, the field of which is uniform 
^ Paul J  Nahin (9 October 2002)  Oliver Heaviside: The Life, Work, and Times of an Electrical Genius of the Victorian Age  JHU Press  ISBN 978-0-8018-6909-9 
^ "The Bumpy Road to Energy Deregulation"  EnPowered  2016-03-28 
^ a b c d e f g h Van Riper, op cit , p  71 
Look up electricity in Wiktionary, the free dictionary 
Basic Concepts of Electricity chapter from Lessons In Electric Circuits Vol 1 DC book and series 



ground_truth: Watt, one joule per second.