Showing posts with label Technolgy. Show all posts
Showing posts with label Technolgy. Show all posts

Tuesday, February 16

Google enters into a news content sharing deal with Seven West Media

Seven West Media, one of Australia’s leading news outlets, has become the first major outlet to enter a licensing deal with Google. In a recent earning briefing, Seven West Media announced that it would generate content for the Google News Showcase platform without going into terms.

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Wednesday, February 3

Jeff Bezos stepping down as Amazon CEO, transitioning to executive chair role

SEATTLE — Amazon founder Jeff Bezos will step down as chief executive of the e-commerce giant, turning over the reins to the company’s longtime cloud-computing boss Andy Jassy. Bezos, who owns The Washington Post, will transition 

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Jeff Bezos Walks Through a One-Way Door, Opening a New Age for Amazon

Jeff Bezos has a formulation about one-way doors and two-way doors—decisions that are irreversible and permanent and those that can always be unwound. Stepping through what’s almost certainly a one-way door on Tuesday, Bezos 


Jeff Bezos is stepping down as Amazon CEO

Amazon founder Jeff Bezos will step down from his role as chief executive later this year and transition to the role of executive chair, the company said Tuesday. He will be replaced by Andy Jassy. Bezos has been Amazon's CEO since its founding in 1995. 

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Tuesday, February 2

Jeff Bezos to Step Down as Amazon CEO

After serving as the CEO of Amazon for more than 25 years, Jeff Bezos is stepping down from the role. The founder of the world's largest e-commerce site announced the move Feb. 2, telling investors that he would transition into the role of executive 

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Sunday, January 31

Apple adds walking with celebrities to Fitness Plus’ features

Apple is adding celebrity-guided walking workouts to Fitness Plus today, with new walks to be added every Monday through the end of April. The new feature, called “Time to Walk,” pairs music and inspirational monologues 

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Sunday, February 27

Power hammer

A power hammer
Power hammers are mechanical forging hammers that use a non-muscular power source to raise the hammer preparatory to striking, and accelerate it onto the work being hammered. Also called "Open Die Power Forging Hammers." They have been used by blacksmiths, bladesmiths, metalworkers, and manufacturers since the late 1880s.

Design and Operation

A water-powered trip hammer, predecessor to the power hammer
A typical power hammer consists of a frame, an anvil, and a reciprocating ram holding a hammer head or die. The workpiece is placed on the lower anvil or die and the head or upper die strikes the workpiece. The power hammer is a direct descendant of the trip hammer, differing in that the power hammer stores potential energy in an arrangement of mechanical linkages and springs, in compressed air, or steam, and by the fact that it accelerates the ram on the downward stroke. This provides more force than simply allowing the weight to fall. Earlier designs like trim hammer, steam drop hammers, board or strap hammers, use the power source to raise the ram, but let its fall be propelled solely by gravity.
Power hammers are rated by weight of moving parts that act directly on the work piece. This includes the weight of the parts that may consist of upper die, ram, mechanical linkage arms and spring(s) or ram, piston, and associated connecting rod(s). Specific design elements are dictated by the power source. The largest power hammer was powered by steam and was rated at 125 short tons (113 t).

Types

Power hammers are generally categorized by their power source.

Steam
Read More: Steam hammer
Steam hammers use steam to drive the hammer. These tended to be the largest models as the great energy of steam was needed to operate them. Locomotive works was one location such large hammers were needed. The workpieces were sometimes so large it required an overhead crane and several men to position the piece in the hammer, and a man to operate the machine.

Mechanical
These hammers tended to smaller and were operated by a single man both holding the workpiece and operating the machine. The majority of these mechanical linkage machines were powered by line shaft flat belt systems or later electric motors that rotated a crank on the machine that drove the ram.

Air
Air-power hammers use pneumatics to drive the hammer.

History

Steam and mechanical power hammers were made into the middle of the 20th century in the USA. At the end of the 19th century the mechanical power hammer became popular in smaller blacksmith and repair shops. These machines were typically rated between 25 and 500 pounds of falling weight. Many may still be seen in use in small manufacturing and artist-blacksmith shops today. In the middle of the 20th century power hammers driven by compressed air began to gain popularity and several manufacturers are currently producing these hammers today.


(source:wikipedia)

Danieli Automation

Danieli Automation is an Italian company, part of the Danieli Group, located in Buttrio (UD). It is a world leader in the field of automation process for the metals industry.

Brief history
Danieli Automation SpA has been established in Buttrio in 1969, based on an intuition of Mr. Luigi Danieli. Born as CEDA (Costruzioni Elettromeccaniche Dispositivi Automazione), the company changed the name in Danieli Centro Automation during the 1990s, to finally take the actual denomination in 2004. At first, the main function was to assist the mother house to design, develop and realize the electrical and automation systems for the machines produced by Danieli Officine Meccaniche SpA. Over the years, the company grown and expanded, becoming today a world reference in the metals industry sector.

Products

Danieli Automation’s products cover the entire range of metals industry activities. The product’s line includes automation systems for:
> Electric steelmaking
> Casting - hot/cold rolling - finishing for flat products
> Casting - rolling - finishing for long products
> Rolling - finishing for seamless tube lines
And:
> Supply chain management
> Electrical & power systems
> Detection and quality control instrumentation

(source:wikipedia)

Saturday, February 26

Twitter

Twitter is a website, owned and operated by Twitter Inc., which offers a social networking and microblogging service, enabling its users to send and read messages called tweets. Tweets are text-based posts of up to 140 characters displayed on the user's profile page. Tweets are publicly visible by default; however, senders can restrict message delivery to just their followers. Users may subscribe to other users' tweets – this is known as following and subscribers are known as followers.

All users can send and receive tweets via the Twitter website, compatible external applications (such as for smartphones), or by Short Message Service (SMS) available in certain countries. While the service is free, accessing it through SMS may incur phone service provider fees. The website is based in San Francisco, California. Twitter also has servers and offices in San Antonio, Texas; and Boston, Massachusetts. Twitter, Inc. was originally incorporated in California, but as of 2007 is incorporated in the jurisdiction of Delaware.
Since its creation in March 2006, and its launch in July 2006, by Jack Dorsey, Twitter has gained popularity worldwide and is estimated to have 190 million users, generating 65 million tweets a day and handling over 800,000 search queries per day. It is sometimes described as the "SMS of the Internet".

History

A blueprint sketch, circa 2006, by Jack Dorsey, envisioning an SMS-based social network.
Invention
Twitter's origins lie in a "daylong brainstorming session" that was held by board members of the podcasting company Odeo. While sitting in a park on a children’s slide and eating Mexican food, Dorsey introduced the idea of an individual using an SMS service to communicate with a small group. The original project code name for the service was twttr, inspired by Flickr and the five-character length of American SMS short codes. The developers initially considered "10958" as a short code, but later changed it to "40404" for "ease of use and memorability". Work on the project started on March 21, 2006, when Dorsey published the first Twitter message at 9:50 PM Pacific Standard Time (PST): "just setting up my twttr".
"[W]e came across the word 'twitter', and it was just perfect. The definition was 'a short burst of inconsequential information,' and 'chirps from birds'. And that's exactly what the product was." – Jack Dorsey
The first Twitter prototype was used as an internal service for Odeo employees and the full version was introduced publicly on July 15, 2006. In October 2006, Biz Stone, Evan Williams, Dorsey, and other members of Odeo formed Obvious Corporation and acquired Odeo and all of its assets–including Odeo.com and Twitter.com–from the investors and shareholders.Twitter spun off into its own company in April 2007.

Reaction
The tipping point for Twitter's popularity was the 2007 South by Southwest (SXSW) festival. During the event, Twitter usage increased from 20,000 tweets per day to 60,000. "The Twitter people cleverly placed two 60-inch plasma screens in the conference hallways, exclusively streaming Twitter messages," remarked Newsweek's Steven Levy. "Hundreds of conference-goers kept tabs on each other via constant twitters. Panelists and speakers mentioned the service, and the bloggers in attendance touted it."
Reaction at the festival was highly positive. Blogger Scott Beale said that Twitter "absolutely ruled" SXSW. Social software researcher Danah Boyd said Twitter "owned" the festival. Twitter staff received the festival's Web Award prize with the remark "we'd like to thank you in 140 characters or less. And we just did!"
Previous Twitter logo, used until September 14, 2010.
The first unassisted off-Earth Twitter message was posted from the International Space Station by NASA astronaut T. J. Creamer on January 22, 2010. By late November 2010, an average of a dozen updates per day were posted on the astronauts' communal account, @NASA_Astronauts.
In August 2010, the company appointed Adam Bain as President of Revenue from News Corp.'s Fox Audience Network.
On September 14, 2010, Twitter launched a redesigned site including a new logo.

Leadership
As chief executive officer, Dorsey saw the startup through two rounds of capital funding by the venture capitalists who backed the company.
On October 16, 2008, Williams took over the role of CEO, and Dorsey became chairman of the board.
On October 4, 2010, Williams announced that he was stepping down as CEO. Dick Costolo, formerly Twitter's chief operating officer, became CEO. According to a Twitter blog, dated October 4, 2010, Williams was to stay with the company and "be completely focused on product strategy."

Growth
The company experienced rapid growth. It had 400,000 tweets posted per quarter in 2007. This grew to 100 million tweets posted per quarter in 2008. In February 2010, Twitter users were sending 50 million tweets per day. By March 2010, the company recorded over 70,000 registered applications, according to the company. As of June 2010, about 65 million tweets were posted each day, equaling about 750 tweets sent each second, according to Twitter. As noted on Compete.com, Twitter moved up to the third-highest-ranking social networking site in January 2009 from its previous rank of twenty-second.
Twitter's usage spikes during prominent events. For example, a record was set during the 2010 FIFA World Cup when fans wrote 2,940 tweets per second in the thirty-second period after Japan scored against Cameroon on June 14, 2010. The record was broken again when 3,085 tweets per second were posted after the Los Angeles Lakers' victory in the 2010 NBA Finals on June 17, 2010, and then again at the close of Japan's victory over Denmark in the World Cup when users published 3,283 tweets per second. When American singer Michael Jackson died on June 25, 2009, company servers crashed after users were updating their status to include the words "Michael Jackson" at a rate of 100,000 tweets per hour.
Twitter acquired application developer Atebits on April 11, 2010. Atebits had developed the Apple Design Award-winning Twitter client Tweetie for the Mac and iPhone. The application, now called "Twitter" and distributed free of charge, is the official Twitter client for the iPhone.
From September through October 2010, the company began rolling out "New Twitter", an entirely revamped edition of twitter.com. Changes included the ability to see pictures and videos without leaving Twitter itself by clicking on individual tweets which contain links to images and clips from a variety of supported websites including YouTube, Flickr, as well as a complete overhaul of the interface, which shifted links such as '@mentions' and 'Retweets' above the Twitter stream, while 'Messages and 'Log Out' became accessible via a black bar at the very top of twitter.com. As of November 1, 2010, the company confirmed that the "New Twitter experience" had been rolled out to all users.

Features
In a 2009 Time essay, technology author Steven Johnson described the basic mechanics of Twitter as "remarkably simple:"
As a social network, Twitter revolves around the principle of followers. When you choose to follow another Twitter user, that user's tweets appear in reverse chronological order on your main Twitter page. If you follow 20 people, you'll see a mix of tweets scrolling down the page: breakfast-cereal updates, interesting new links, music recommendations, even musings on the future of education.

Messages
Users can group posts together by topic or type by use of hashtags – words or phrases prefixed with a "#" sign. Similarly, the "@" sign followed by a username is used for mentioning or replying to other users. To repost a message from another Twitter user, and share it with one's own followers, the retweet function is symbolized by "RT" in the message.
In late 2009, the "Twitter Lists" feature was added, making it possible for users to follow (as well as mention and reply to) lists of authors instead of individual authors.

Through SMS, users can communicate with Twitter through five gateway numbers: short codes for the United States, Canada, India, New Zealand, and an Isle of Man-based number for international use. There is also a short code in the United Kingdom which is only accessible to those on the Vodafone, O2 and Orange networks. In India, since Twitter only supports tweets from Bharti Airtel, an alternative platform called smsTweet was set up by a user to work on all networks. A similar platform called GladlyCast exists for mobile phone users in Singapore, Malaysia and the Philippines.
The messages were initially set to 140-character limit for compatibility with SMS messaging, introducing the shorthand notation and slang commonly used in SMS messages. The 140-character limit has also increased the usage of URL shortening services such as bit.ly, goo.gl, and tr.im, and content-hosting services, such as Twitpic, memozu.com and NotePub to accommodate multimedia content and text longer than 140 characters. Twitter uses bit.ly for automatic shortening of all URLs posted on its website.

Tweet contents

Content of Tweets according to Pear Analytics.
News
Spam
Self-promotion
Pointless babble
Conversational
Pass-along value
San Antonio-based market-research firm Pear Analytics analyzed 2,000 tweets (originating from the US and in English) over a two-week period in August 2009 from 11:00 AM to 5:00 PM (CST) and separated them into six categories:
Content of Tweets according to Pear Analytics.
  News
  Spam
  Self-promotion
  Pointless babble
  Conversational
  Pass-along value
Social networking researcher Danah Boyd responded to the Pear Analytics survey by arguing that what the Pear researchers labelled "pointless babble" is better characterized as "social grooming" and/or "peripheral awareness" (which she explains as persons "want[ing] to know what the people around them are thinking and doing and feeling, even when co-presence isn’t viable").


Rankings
Twitter is ranked as one of the ten-most-visited websites worldwide by Alexa's web traffic analysis. Daily user estimates vary as the company does not publish statistics on active accounts. A February 2009 Compete.com blog entry ranked Twitter as the third most used social network based on their count of 6 million unique monthly visitors and 55 million monthly visits. In March 2009, a Nielsen.com blog ranked Twitter as the fastest-growing website in the Member Communities category for February 2009. Twitter had annual growth of 1,382 percent, increasing from 475,000 unique visitors in February 2008 to 7 million in February 2009. It was followed by Zimbio with a 240 percent increase, and Facebook with a 228 percent increase. However, Twitter has a user retention rate of forty percent.


Adding and following content
There are numerous tools for adding content, monitoring content and conversations including Tweetdeck, Salesforce.com, HootSuite, and Twitterfeed. Less than half of tweets are posted using the web user interface with most users using third-party applications (based on analysis of 500 million tweets by Sysomos).

Authentication
As of August 31, 2010, third-party Twitter applications are required to use OAuth, an authentication method that does not require users to enter their password into the authenticating application. Previously, the OAuth authentication method was optional, it is now compulsory and the user-name/password authentication method has been made redundant and is no longer functional. Twitter stated that the move to OAuth will mean "increased security and a better experience."

Demographics
Twitter is mainly used by older adults who might not have used other social sites before Twitter, said Jeremiah Owyang, an industry analyst studying social media. "Adults are just catching up to what teens have been doing for years," he said. According to comScore only eleven percent of Twitter's users are aged twelve to seventeencomScore attributes this to Twitter's "early adopter period" when the social network first gained popularity in business settings and news outlets attracting primarily older users. However, comScore as of late, has stated that Twitter has begun to "filter more into the mainstream", and "along with it came a culture of celebrity as Shaq, Britney Spears and Ashton Kutcher joined the ranks of the Twitterati."
According to a study by Sysomos in June 2009, women make up a slightly larger Twitter demographic than men — fifty-three percent over forty-seven percent. It also stated that five percent of users accounted for seventy-five percent of all activity, and that New York has the most Twitter users.
According to Quancast, twenty-seven million people in the US used Twitter as of September 3, 2009. Sixty-three percent of Twitter users are less than thirty-five years old; sixty percent of Twitter users are Caucasian, but a higher than average (compared to other Internet properties) are African American (sixteen percent) and Hispanic (eleven percent); fifty-eight percent of Twitter users have a total household income of at least $60,000.

Finances
Twitter's San Francisco headquarters located at 795 Folsom St.
Twitter raised over US$57 million from venture capitalist growth funding, although exact numbers are not publicly disclosed. Twitter's first A round of funding was for an undisclosed amount that is rumored to have been between $1 million and $5 million. Its second B round of funding in 2008 was for $22 million and its third C round of funding in 2009 was for $35 million from Institutional Venture Partners and Benchmark Capital along with an undisclosed amount from other investors including Union Square Ventures, Spark Capital and Insight Venture Partners. Twitter is backed by Union Square Ventures, Digital Garage, Spark Capital, and Bezos Expeditions.
In May 2008, The Industry Standard remarked that Twitter's long-term viability is limited by a lack of revenue. Twitter board member Todd Chaffee forecast that the company could profit from e-commerce, noting that users may want to buy items directly from Twitter since it already provides product recommendations and promotions.
On April 13, 2010, Twitter announced plans to offer paid advertising for companies that would be able to purchase "promoted tweets" to appear in selective search results on the Twitter website, similar to Google Adwords' advertising model. As of April 13, Twitter announced it had already signed up a number of companies wishing to advertise including Sony Pictures, Red Bull, Best Buy, and Starbucks.
In July 2009, some of Twitter's revenue and user growth documents were published on TechCrunch after being illegally obtained by the hacker Croll Hacker. The documents projected 2009 revenues of $400,000 in the third quarter and $4 million in the fourth quarter along with 25 million users by the end of the year. The projections for the end of 2013 were $1.54 billion in revenue, $111 million in net earnings, and 1 billion users. No information about how Twitter planned to achieve those numbers was published. In response, Twitter co-founder Biz Stone published a blog post suggesting the possibility of legal action against the hacker.
Though the company only started selling ads midway through 2010 (late spring), it still managed to generate $45 million in annual revenue. Even operating at a loss through most of 2010, an addition of $200 million in new venture capital in December 2010 and a forecasted $100 million to $110 million in revenue for 2011 rose the company's valuation to approximately $3.7 billion as of February 2011.
Twitter has been identified as a possible candidate for an initial public offering by 2013.

Technology

Implementation
The Twitter Web interface uses the Ruby on Rails framework, deployed on a performance enhanced Ruby Enterprise Edition implementation of Ruby.
From the spring of 2007 until 2008 the messages were handled by a Ruby persistent queue server called Starling,but since 2009 implementation has been gradually replaced with software written in Scala. The service's application programming interface (API) allows other web services and applications to integrate with Twitter.

Interface
On April 30, 2009, Twitter adjusted its web interface, adding a search bar and a sidebar of "trending topics" — the most common phrases appearing in messages. Biz Stone explains that all messages are instantly indexed and that "with this newly launched feature, Twitter has become something unexpectedly important — a discovery engine for finding out what is happening right now."

Outages

The Twitter fail whale error message.
When Twitter experiences an outage, users see the "fail whale" error message image created by Yiying Lu, illustrating several red birds using a net to hoist a whale from the ocean captioned "Too many tweets! Please wait a moment and try again."

Twitter had approximately ninety-eight percent uptime in 2007 (or about six full days of downtime). The downtime was particularly noticeable during events popular with the technology industry such as the 2008 Macworld Conference & Expo keynote address.
May 2008 – Twitter's new engineering team made architectural changes to deal with the scale of growth. Stability issues resulted in down time or temporary feature removal.
August 2008 – Twitter withdrew free SMS services from users in the United Kingdom and for approximately five months instant messaging support via a XMPP bot was listed as being "temporarily unavailable".
October 10, 2008 – Twitter's status blog announced that instant messaging (IM) service was no longer a temporary outage and needed to be revamped. It was announced that Twitter aims to return its IM service pending necessary major work.
June 12, 2009 – In what was called a potential "Twitpocalypse", the unique numerical identifier associated with each tweet exceeded the limit of 32-bit signed integers (2,147,483,647 total messages).[88] While Twitter itself was not affected, some third-party clients could no longer access recent tweets. Patches were quickly released, though some iPhone applications had to wait for approval from the App Store.
September 22, 2009 – The identifier exceeded the limit for 32-bit unsigned integers (4,294,967,296 total messages) again breaking some third-party clients.
August 6, 2009 – Twitter and Facebook suffered from a denial-of-service attack, causing the Twitter website to go offline for several hours. It was later confirmed that the attacks were directed at one pro-Georgian user around the anniversary of the 2008 South Ossetia War, rather than the sites themselves.
December 17, 2009 – A hacking attack replaced the website's welcoming screen with an image of a green flag and the caption "This site has been hacked by Iranian Cyber Army" for nearly an hour. No connection between the hackers and Iran has been established.
November 2010 – A number of accounts encountered a fault that resulted in them seeing the "fail whale" when they tried to login to their accounts. The accounts themselves were not locked out as account holders could still see their "mentions" page and post from there. But the timeline and a number of other features were unavailable during this outage (which remains ongoing).

Privacy and security
Twitter messages are public but users can also send private messages. Twitter collects personally identifiable information about its users and shares it with third parties. The service reserves the right to sell this information as an asset if the company changes hands. While Twitter displays no advertising, advertisers can target users based on their history of tweets and may quote tweets in ads directed specifically to the user.
A security vulnerability was reported on April 7, 2007, by Nitesh Dhanjani and Rujith. Since Twitter used the phone number of the sender of an SMS message as authentication, malicious users could update someone else's status page by using SMS spoofing. The vulnerability could be used if the spoofer knew the phone number registered to their victim's account. Within a few weeks of this discovery Twitter introduced an optional personal identification number (PIN) that its users could use to authenticate their SMS-originating messages.
On January 5, 2009, 33 high-profile Twitter accounts were compromised after a Twitter administrator's password was guessed by a dictionary attack. Falsified tweets — including sexually explicit and drug-related messages — were sent from these accounts.
Twitter launched the beta version of their "Verified Accounts" service on June 11, 2009, allowing famous or notable people to announce their Twitter account name. The home pages of these accounts display a badge indicating their status.
In May 2010, a bug was discovered by İnci Sözlük users that allowed Twitter users to force others to follow them without the other users' consent or knowledge. For example, comedian Conan O'Brien's account, which had been set to follow only one person, was changed to receive nearly 200 malicious subscriptions.
In response to Twitter's security breaches, the Federal Trade Commission brought charges against the service which were settled on June 24, 2010. This was the first time the FTC had taken action against a social network for security lapses. The settlement requires Twitter to take a number of steps to secure users' private information, including maintenance of a "comprehensive information security program" to be independently audited biannually.

On December 14, 2010, the United States Department of Justice issued a subpoena directing Twitter to provide information for accounts registered to or associated with WikiLeaks. Twitter decided to notify its users and said in a statement, "...it's our policy to notify users about law enforcement and governmental requests for their information, unless we are prevented by law from doing so"
A "MouseOver" exploit occurred on September 21, 2010, when an XSS Worm became active on Twitter. When an account user held the mouse cursor over blacked out parts of a tweet, the worm within the script would automatically open links and re-post itself on the reader's account. The exploit was then re-used to post pop-up ads and links to pornographic sites. The origin is unclear but Pearce H. Delphin (known on Twitter as @zzap) and a Scandinavian developer, Magnus Holm, both claim to have modified the exploit of a user, possibly Masato Kinugawa, who was using it to create coloured Tweets. Kinugawa, a Japanese developer, reported the XSS vulnerability to Twitter on August 14. Later, when he found it was exploitable again, he created the account 'RainbowTwtr' and used it to post coloured messages.Delphin says he exposed the security flaw by tweeting a JavaScript function for "onMouseOver", and Holm later created and posted the XSS Worm that automatically re-tweeted itself.Security firm Sophos reported the virus was spread by people doing it for "fun and games", but noted it could be exploited by cybercriminals. Twitter issued a statement on their status blog at 13:50 UTC that "The exploit is fully patched". Twitter representative Carolyn Penner said no charges would be pressed.

Open source
Twitter released several open source projects developed while overcoming technical challenges of their service. Notable projects are the Gizzard Scala framework for creating distributed datastores and the distributed graph database FlockDB.

URL shortener
t.co is a URL shortening service created by Twitter. It is only available for links posted to Twitter and not available for general use. Eventually all links posted to Twitter will use a t.co wrapper. Twitter hopes that the service will be able to protect users from malicious sites, and will use it to track clicks on links within tweets.
Having previously used the services of third parties TinyURL and bit.ly, Twitter began experimenting with its own URL shortening service for direct messages in March 2010 using the twt.tl domain, before it purchased the t.co domain. The service has been[clarification needed] being tested on the main site using the accounts @TwitterAPI, @rsarver and @raffi.On September 2, 2010, an email from Twitter to users said they would be expanding the roll-out of the service to users.

Uses


 Twitter usage
Twitter has been used for a variety of purposes in many different industries and scenarios. For example, it has been used to organize protests, sometimes referred to as "Twitter Revolutions" and which include the 2011 Egyptian protests, 2010–2011 Tunisian protests, 2009–2010 Iranian election protests, and 2009 Moldova civil unrest. The service has also been used in emergencies and political campaigning.
It is also used for direct communication among social groups and organizations, with the use of "hashtags." For instance, #edchat, used at the end of a tweet, means that the communication will be viewed by all users who follow the topic which refers to an ongoing chat among educators.

Reception

In 2006, when Twitter launched under the name "Twttr", Michael Arrington of TechCrunch commented that although he liked the service, he also noted that he felt uncomfortable with the fact that every user's Twitter page is available to the public.

Change of focus

The mobile version of twitter.com
Twitter emphasized its news and information-network strategy in November 2009 by changing the question asked users for status updates from "What are you doing?" to "What's happening?" Entertainment Weekly put it on its end-of-the-decade, "best-of" list, saying, "Limiting yourself to 140 characters—the maximum for messages on this diabolically addictive social-networking tool—is easy."
On November 22, 2010, Biz Stone, a cofounder of the company, expressed for the first time the idea of a Twitter news network, a concept of wire-like news service he has been working on for years.

Criticism

In May 2008, The Wall Street Journal wrote that social-networking services such as Twitter "elicit mixed feelings in the technology-savvy people who have been their early adopters. Fans say they are a good way to keep in touch with busy friends. But some users are starting to feel 'too' connected, as they grapple with check-in messages at odd hours, higher cellphone bills and the need to tell acquaintances to stop announcing what they're having for dinner."
"Using Twitter for literate communication is about as likely as firing up a CB radio and hearing some guy recite the Iliad", said tech writer Bruce Sterling. "For many people, the idea of describing your blow-by-blow activities in such detail is absurd," hypothesized writer Clive Thompson in September 2008. "Why would you subject your friends to your daily minutiae? And conversely, how much of their trivia can you absorb? The growth of ambient intimacy can seem like modern narcissism taken to a new, supermetabolic extreme—the ultimate expression of a generation of celebrity-addled youths who believe their every utterance is fascinating and ought to be shared with the world."
On the other hand Steve Dotto opined that part of Twitter's appeal is the challenge of trying to publish such messages in tight constraints. "The qualities that make Twitter seem inane and half-baked are what makes it so powerful," says Jonathan Zittrain, professor of Internet law at Harvard Law School.

In 2009, Nielsen Online reported that Twitter has a user retention rate of forty percent. Many people stop using the service after a month therefore the site may potentially reach only about ten percent of all Internet users. In 2009, Twitter won the "Breakout of the Year" Webby Award.
During a February 2009 discussion on National Public Radio's Weekend Edition, the journalist Daniel Schorr stated that Twitter accounts of events lacked rigorous fact-checking and other editorial improvements. In response, Andy Carvin gave Schorr two examples of breaking news stories that played out on Twitter and said users wanted first-hand accounts and sometimes debunked stories.
In an episode of The Daily Show on February 26, 2009, guest Brian Williams, a journalist, described tweets as only referring to the condition of the author. Williams implied that he would never use Twitter because nothing he did was interesting enough to publish in Twitter format.During another episode of The Daily Show on March 2, 2009, host Jon Stewart negatively portrayed members of Congress who chose to "tweet" during President Obama's address to Congress (on February 24, 2009) rather than pay attention to the content of the speech. The show's Samantha Bee satirized media coverage of the service saying "there's no surprise young people love it – according to reports of young people by middle-aged people."
Time magazine acknowledged growing level of influence in its 2010 Time 100 most influential people. To determine the influence of people it used a formula based on famous social networking sites, Twitter and Facebook. The list ranges from Barack Obama and Oprah Winfrey to Lady Gaga and Ashton Kutcher. The formula was (Twitter followers) x 2 + (facebook connections) divided by 2.
In March 2009, the comic strip Doonesbury began to satirize Twitter. Many characters highlighted the triviality of tweets although one defended the need to keep up with the constant-update trend. SuperNews! similarly satirized Twitter as an addiction to "constant self-affirmation" and said tweets were nothing more than "shouts into the darkness hoping someone is listening".
Censorship

Censorship of Twitter
Censorship of Twitter has occurred in Iran, China, Egypt, and South Korea.
Censorship of WikiLeaks by Twitter
In December 2010, allegations have been made by several IT-news websites and other media reporting that Twitter appeared to engage in censorship activities by impeding WikiLeaks related tweets from becoming trending topics, despite high numbers of tweets concerning WikiLeaks due to activities such as the United States diplomatic cables leak. However, Twitter has denied any involvement with altering Trend results explaining that "WikiLeaks and cablegate have trended worldwide or in specific locations."


(source:wikipedia)

Wednesday, January 19

List of largest power stations in the wor

The following page lists five of the largest power stations in the world of each type, in terms of current installed electrical capacity. Non-renewable power stations are those that run on coal, fuel oils and natural gas, while renewable power stations run on fuel sources such as biomass, geothermal heat, hydro, solar energy, solar heat, tides, waves and the wind. Only the most significant fuel source are listed for power stations that run on multiple sources.

At present, the largest power generating facility ever built is the Three Gorges Dam in China. The facility generates power by utilizing 26 turbines, with 8 more units (6 × 700 MW, 2 × 50 MW) under construction. Each of the current operational units has a capacity of 700 MW,totalling the installed capacity to 18,200 MW, more than twice the installed capacity of the largest nuclear power station, the Kashiwazaki-Kariwa at 8,212 MW. Upon full completion of the Three Gorges Dam in 2011, the total installed capacity would top 22,500 MW, just 5,500 MW less than being twice the capacity of the second largest power generating facility, the Itaipu Dam, at 14,000 MW.


Although currently only a proposal, the Grand Inga Dam in Congo would surpass all existing power stations, including the Three Gorges Dam, if construction commences as planned in 2014. The design targets to top 39,000 MW in installed capacity, nearly twice that of the Three Gorges. At the time of the dam's initial proposal, this was sufficient to meet the entire power demand of the African continent.

Top 10 largest power producing facilities
Three Gorges, currently the largest hydroelectric power station, and the
 largest power producing body ever built, at 18,200 MW.

Rank Station Country Location Capacity (MW) Fuel type Ref
1 Three Gorges Dam China 30°49′15″N 111°00′08″E 18,200 Hydroelectricity
2 Itaipu Dam Brazil
Paraguay 25°24′31″S 54°35′21″W 14,000 Hydroelectricity
3 Guri Dam Venezuela 07°45′59″N 62°59′57″W 10,200 Hydroelectricity 
4 Tucurui Dam Brazil 03°49′53″S 49°38′36″W 8,370 Hydroelectricity 
5 Kashiwazaki-Kariwa Nuclear Power Plant Japan 37°25′45″N 138°35′43″E 8,212 Nuclear 
6 Bruce Nuclear Generating Station Canada 44°19′31″N 81°35′58″W 7,276 Nuclear
7 Grand Coulee Dam United States 47°57′23″N 118°58′56″W 6,809 Hydroelectricity
8 Longtan Dam China 25°01′38″N 107°02′51″E 6,426 Hydroelectricity 
9A Krasnoyarsk Dam Russia 55°56′05″N 92°17′37″E 6,000 Hydroelectricity
9A Zaporizhzhia Nuclear Power Plant Ukraine 47°30′44″N 34°35′09″E 6,000 Nuclear 


Non-renewable power stations

Coal

Bełchatów, the fifth largest coal-fired power station at 4,440 MWe.
Rank Station Country Location Capacity (MW) Ref
1 Taichung Power Plant Taiwan 24°12′46″N 120°28′52″E 5,780 
2 Tuoketuo Power Station China 40°11′49″N 111°21′52″E 5,400 
3B Guodian Beilun Power Station China 29°56′37″N 121°48′57″E 5,000
3B Waigaoqiao Power Station China 31°21′21″N 121°35′54″E 5,000 
5 Bełchatów Power Station Poland 51°15′59″N 19°19′50″E 4,440 


Fuel oil

Surgut-2, the largest oil-fired power station at 4,800 MWe.
Rank Station Country Location Capacity (MW) Ref
1 Surgut-2 Power Station Russia 61°16′46″N 73°30′45″E 4,800 
2 Kashima Power Station Japan 35°52′47″N 140°41′22″E 4,400
3 Surgut-1 Power Station Russia 61°16′46″N 73°29′20″E 3,280
4 Hirono Power Station Japan 37°14′18″N 141°01′04″E 3,200 
5 Ryazan Power Station Russia 54°02′00″N 39°47′30″E 2,800


Natural gas

Futtsu, the fifth largest natural gas power station at 3,520 MWe.
Rank Station Country Location Capacity (MW) Ref
1 Kawagoe Power Station Japan 35°00′25″N 136°41′20″E 4,802
2 Chita Power Station Japan 34°59′12″N 136°50′37″E 3,966 
3C Kostromskaya Power Station Russia 57°27′34″N 41°10′30″E 3,600 
3C Sodegaura Power Station Japan 35°27′45″N 139°58′37″E 3,600 
5 Futtsu Power Station Japan 35°20′35″N 139°50′02″E 3,520 


Nuclear

Kashiwazaki-Kariwa, the largest nuclear power station at 8,212 MWe.
Rank Station Country Location Capacity (MW) Ref
1 Kashiwazaki-Kariwa Nuclear Power Plant Japan 37°25′45″N 138°35′43″E 8,212 
2 Bruce Nuclear Generating Station Canada 44°19′31″N 81°35′58″W 7,276
3 Zaporizhzhia Nuclear Power Plant Ukraine 47°30′44″N 34°35′09″E 6,000
4 Uljin Nuclear Power Plant South Korea 37°05′34″N 129°23′01″E 5,881 
5 Yeonggwang Nuclear Power Station South Korea 35°24′54″N 126°25′26″E 5,875


Oil shale

Eesti Power Station, the largest oil shale-fired power station at 1,615 MW.
Rank Station Country Location Capacity (MW) Ref
1 Eesti Power Station Estonia 59°16′10″N 27°54′08″E 1,615
2 Balti Power Station Estonia 59°21′12″N 28°07′22″E 765
3 Huadian Oil Shale Plant China 100
4 Mishor Rotem Power Station Israel 31°03′19″N 35°11′04″E 13
5 Dotternhausen Rohrbach Zement Factory Germany 9.9 


Peat

Shatura, largest peat-fired power station at 1,020 MW.
Rank Station Country Location Capacity (MW) Ref
1 Shatura Power Station Russia 55°35′00″N 39°33′40″E 1,020
2 Kirov Power Station Russia 58°37′16″N 49°35′47″E 300
3 Keljonlahti Power Station Finland 62°11′33″N 25°44′14″E 209 
4 Toppila Power Station Finland 65°02′13″N 25°29′17″E 190 
5 Haapavesi Power Station Finland 64°07′19″N 25°24′47″E 154


Renewable power stations


Biofuel

Alholmens Kraft, the largest biofuel power station at 265 MWe.
Rank Station Country Location Capacity (MW) Ref
1 Alholmens Kraft Power Station Finland 63°42′07″N 22°42′35″E 265 
2 Kaukaan Voima Power Station Finland 61°04′00″N 28°14′40″E 125 
3 Rumford Cogen Power Station United States 44°33′07″N 70°32′34″W 102 
4 Igelsta Power Station Sweden 85
5 Multitrade Power Station United States 80 


Geothermal

Wairakei, the fourh largest geothermal power station at 181 MWe.
Rank Station Country Location Capacity (MW) Ref
1 Cerro Prieto Geothermal Power Station Mexico 32°23′57″N 115°14′19″W 720
2 Hellisheidi Power Station Iceland 64°02′14″N 21°24′03″W 300
3 Wayang Windu Geothermal Power Station Indonesia 07°12′00″S 107°37′30″E 227
4 Wairakei Power Station New Zealand 38°37′37″S 176°06′19″E 181
5 Reykjanes Power Station Iceland 63°49′35″N 22°40′55″W 150 


Hydroelectric

Conventional

Three Gorges, currently the largest hydroelectric power station, and the
 largest power producing body ever built, at 18,200 MW.
Rank Station Country Location Capacity (MW) Ref
1 Three Gorges Dam China 30°49′15″N 111°00′08″E 18,200
2 Itaipu Dam Brazil
Paraguay 25°24′31″S 54°35′21″W 14,000
3 Guri Dam Venezuela 07°45′59″N 62°59′57″W 10,200
4 Tucurui Dam Brazil 03°49′53″S 49°38′36″W 8,370
5 Grand Coulee Dam United States 47°57′23″N 118°58′56″W 6,809 


Pumped-storage

Grande Dixence, the third largest pumped-storage hydroelectric power station at 2,069 MW.
Rank Station Country Location Capacity (MW) Ref
1 Bath County Pumped Storage Station United States 38°12′32″N 79°48′00″W 2,772 
2 Guangdong Pumped Storage Power Station China 23°45′52″N 113°57′12″E 2,400 
3 Grande Dixence Dam (Cleuson-Dixence Complex) Switzerland 46°04′50″N 07°24′14″E 2,069 
4 Okutataragi Hydroelectric Power Station Japan 35°14′13″N 134°49′55″E 1,932 
5 Ludington Pumped Storage Power Plant United States 43°53′37″N 86°26′43″W 1,872 


Run-of-the-river

Chief Joseph, the largest run-of-the-river hydroelectric power station at2,620 MW.
Read More: Run-of-the-river hydroelectricity and List of run-of-the-river hydroelectric power stations
Rank Station Country Location Capacity (MW) Ref
1 Chief Joseph Dam United States 47°59′43″N 119°38′00″W 2,620
2 John Day Dam United States 45°52′49″N 120°41′40″W 2,160
3 Beauharnois Hydroelectric Power Station Canada 45°18′50″N 73°54′32″W 1,903 
4 The Dalles Dam United States 45°36′44″N 121°08′04″W 1,779 
5 Ghazi Barotha Dam Pakistan 03°46′48″N 72°15′35″E 1,450 


Tide

Rance, the largest tidal power station at 240 MW.
Rank Station Country Location Capacity (MW) Ref
1 Rance Tidal Power Station France 48°37′05″N 02°01′24″W 240
2 Annapolis Royal Generating Station Canada 44°45′07″N 65°30′40″W 20
3 Jiangxia Tidal Power Station China 28°20′34″N 121°14′25″E 3.9
4 Kislaya Guba Tidal Power Station Russia 69°22′37″N 33°04′34″E 1.7 
5 Uldolmok Tidal Power Station South Korea 34°32′07″N 126°14′06″E 1.0 


Solar power
Flat-panel photovoltaic
Rank Station Country Location Capacity (MW) Ref
1 Finsterwalde Solar Park Germany 51°34′7″N 13°44′15″E 80.7 
2 Sarnia Photovoltaic Power Plant Canada 42°56′16″N 82°20′30″W 80 
3 Rovigo Photovoltaic Power Plant Italy 70 
4 Olmedilla Photovoltaic Park Spain 39°37′43″N 02°04′37″W 60 
5 Strasskirchen Solar Park Germany 48°48′58″N 12°43′53″E 54 


Concentrated photovoltaic

Sevilla, the second largest CPV power station at 1.2 MW.
This section requires expansion.
Rank Station Country Location Capacity (MWe) Ref
1 Casaquemada Photovoltaic Power Plant Spain 1.9
2 Sevilla Photovoltaic Power Plant Spain 37°25′18″N 06°15′25″W 1.2 
3D Victor Valley College CPV Plant United States 34°28′31″N 117°15′46″W 1
3D Questa Photovoltaic Power Plant United States 36°42′31″N 105°37′09″W 1


Concentrated solar thermal


Solnova, the largest CSP power station at 150 MWe.
Rank Station Country Location Capacity (MW) Ref
1 Solnova Solar Power Station Spain 37°25′00″N 06°17′20″W 150 
2 Andasol Solar Power Station Spain 37°13′43″N 03°04′07″W 100 
3E SEGS VIII United States 35°01′53″N 117°21′23″W 80 
3E SEGS IX United States 35°01′56″N 117°20′16″W 80 
5 Nevada Solar One United States 35°48′00″N 114°58′06″W 64 


Wave
Aguçadoura, the largest wave farm at 2.25 MW.
This section requires expansion.
Rank Station Country Location Capacity (MW) Ref
1 Aguçadoura Wave Farm Portugal 41°25′57″N 08°50′33″W 2.25
2 Islay Limpet Scotland 55°41′24″N 06°31′15″W 0.5 
3 SDE Sea Waves Power Plant Israel 32°05′59″N 34°46′24″E 0.04


Wind

Tehachapi Pass, the third largest wind farm at 705 MW.
Read More: Wind power, List of onshore wind farms, and List of offshore wind farms
Rank Station Country Location Capacity (MW) Type Ref
1 Roscoe Wind Farm United States 32°26′41″N 100°34′23″W 782 Onshore 
2 Horse Hollow Wind Energy Center United States 32°19′00″N 99°59′59″W 736 Onshore 
3 Tehachapi Pass Wind Farm United States 35°06′08″N 118°16′58″W 705 Onshore
4 Capricorn Ridge Wind Farm United States 31°54′08″N 100°53′56″W 663 Onshore 
5 San Gorgonio Pass Wind Farm United States 33°55′12″N 118°35′24″W 615 Onshore 


(source:wikipedia)